U.S. patent application number 17/654753 was filed with the patent office on 2022-06-23 for systems and methods for operating unmanned aerial vehicles.
The applicant listed for this patent is SZ DJI TECHNOLOGY CO., LTD.. Invention is credited to Zongyao QU, Tao WU.
Application Number | 20220197309 17/654753 |
Document ID | / |
Family ID | 1000006196753 |
Filed Date | 2022-06-23 |
United States Patent
Application |
20220197309 |
Kind Code |
A1 |
QU; Zongyao ; et
al. |
June 23, 2022 |
SYSTEMS AND METHODS FOR OPERATING UNMANNED AERIAL VEHICLES
Abstract
An unmanned aerial vehicle (UAV) includes a central body, an
arm, and a propulsion unit. The arm extends outwardly from the
central body. The propulsion unit is coupled to the arm. At least
one of the arm or the propulsion unit is adjustable in response to
a change in a center of gravity of the UAV.
Inventors: |
QU; Zongyao; (Shenzhen,
CN) ; WU; Tao; (Shenzhen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SZ DJI TECHNOLOGY CO., LTD. |
Shenzhen |
|
CN |
|
|
Family ID: |
1000006196753 |
Appl. No.: |
17/654753 |
Filed: |
March 14, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16271530 |
Feb 8, 2019 |
11275389 |
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17654753 |
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PCT/CN2016/095708 |
Aug 17, 2016 |
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16271530 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G05D 1/0011 20130101;
G05D 1/085 20130101; B64C 2201/14 20130101; G01M 1/12 20130101;
B64C 2201/146 20130101; B64C 2201/141 20130101; G05D 1/0094
20130101; B64C 17/02 20130101; B64C 39/024 20130101; B64C 2201/027
20130101; B64C 27/02 20130101 |
International
Class: |
G05D 1/08 20060101
G05D001/08; B64C 39/02 20060101 B64C039/02; B64C 27/02 20060101
B64C027/02; G01M 1/12 20060101 G01M001/12; B64C 17/02 20060101
B64C017/02; G05D 1/00 20060101 G05D001/00 |
Claims
1. An unmanned aerial vehicle (UAV) comprising: a central body; an
arm extending outwardly from the central body; and a propulsion
unit coupled to the arm, at least one of the arm or the propulsion
unit being adjustable in response to a change in a center of
gravity of the UAV.
2. The UAV of claim 1, wherein: a distance of the propulsion unit
from a reference point on the central body is adjustable by
manipulating a configuration of the arm in response to the change
in the center of gravity of the UAV; and the configuration of the
arm includes a length of the arm.
3. The UAV of claim 2, wherein the arm is extendable.
4. The UAV of claim 2, wherein the propulsion unit includes a
rotor, and the distance of the propulsion unit from the reference
point includes a distance from a rotational axis of the rotor to
the reference point.
5. The UAV of claim 2, further comprising: a payload; wherein the
change in the center of gravity of the UAV includes a change in a
configuration of the payload.
6. The UAV of claim 5, wherein the payload includes a telescoping
feature.
7. The UAV of claim 1, wherein: the propulsion unit includes a
rotor and a set of rotor blades coupled to the rotor; and an
angular velocity of the set of rotor blades is adjustable in
response to the change in the center of gravity of the UAV.
8. An unmanned aerial vehicle (UAV) attitude control method
comprising: determining that a change in a center of gravity of the
UAV occurs; and changing a configuration of at least one of an arm
or a propulsion unit arranged at the arm to counter the change in
the center of gravity of the UAV.
9. The method of claim 8, wherein determining that the change in
the center of gravity of the UAV occurs includes: receiving a
signal indicating the change in the center of gravity of the
UAV.
10. The method of claim 9, wherein the signal indicates a change in
a configuration of a payload of the UAV.
11. The method of claim 10, wherein the signal indicates at least
one of a change in a mass of the payload or a redistribution of the
mass of the payload.
12. The method of claim 10, wherein the signal indicates an
extension or retraction of a telescoping feature of the
payload.
13. The method of claim 12, wherein the telescoping feature
including at least one of a telescoping arm, a telescoping lens
unit, or a telescoping nozzle of the payload.
14. The method of claim 8, wherein changing the configuration of
the at least one of the arm or the propulsion unit includes
changing the configuration of the arm to change a distance of the
propulsion unit from a reference point on the central body to
counter the change in the center of gravity.
15. The method of claim 14, wherein: the distance is a first
distance; and changing the configuration of the arm includes
positioning the propulsion unit at a second distance further away
from the reference point on the central body to counter the change
in the center of gravity.
16. The method of claim 14, wherein the reference point is at a
center of the central body.
17. The method of claim 14, wherein changing the configuration of
the arm includes changing a length of the arm.
18. The method of claim 8, further comprising: determining a change
in an angular velocity of a rotor of the propulsion unit.
19. The method of claim 8, further comprising: receiving
information from a sensor on the UAV to determine the change in the
configuration of the arm.
20. A controller for controlling an attitude of an unmanned aerial
vehicle (UAV) comprising: a center of gravity controller configured
to determine a change in a configuration of an arm or a propulsion
unit in response to a change in a center of gravity of the UAV.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
16/271,530, filed on Feb. 8, 2019, which is a continuation
application of International Application No. PCT/CN2016/095708,
filed on Aug. 17, 2016, the entire contents of both of which are
incorporated herein by reference.
BACKGROUND
[0002] Unmanned vehicles, such as unmanned aerial vehicles (UAV),
can have a wide variety of civilian, commercial and/or military
applications. A UAV may be used, for example, in aerial
photography, landscape analysis, environmental sensing,
surveillance, reconnaissance, and/or exploration tasks. UAV flight
stability may be desirable for various applications in which UAVs
are used.
SUMMARY
[0003] Redistribution of and/or changes in the mass of any portion
of the UAV may affect the stability of the UAV flight. For example,
change in the configuration state of a payload of the UAV may cause
a change in the center of gravity of the UAV. Changes in the center
of gravity of the UAV may affect the stability of the UAV flight.
Operation of the UAV may involve adjustment in the control of the
UAV to account for the changes in the center of gravity. Reliance
upon adjustment of only the angular velocity of one or more rotors
of the UAV may limit the ability of the UAV to respond to changes
in the center of gravity. The present disclosure provides systems
and methods for improved operating a movable vehicle, including an
unmanned vehicle, such as an unmanned aerial vehicle (UAV), such
that the UAV demonstrates increased ability to respond to changes
in the center of gravity of the UAV.
[0004] According to some aspects, a controller for controlling
operation of an unmanned aerial vehicle may include an input
configured for receiving a first signal indicating a change in a
center of gravity of the unmanned aerial vehicle, wherein the
unmanned aerial vehicle comprises a plurality of arms, at least one
of the plurality of arms extending from a central body, and a
plurality of propulsion units, at least one of the plurality of
propulsion units being positioned on a corresponding arm at a
distance from a reference point on the central body. The controller
can include a processor configured to determine, in response to the
change in the center of gravity, a change in a configuration of the
corresponding arm of the unmanned aerial vehicle to change the
distance of the at least one of the plurality of propulsion units
from the reference point to counter the change in the center of
gravity.
[0005] In some embodiments, the change in the configuration of the
corresponding arm is configured to position the at least one of the
plurality of propulsion units at a second distance further away
from the reference point on the central body to counter the change
in the center of gravity. some embodiments, the reference point is
at a center of the central body. In some embodiments, the distance
is a distance between a rotational axis of the at least one of the
plurality of propulsion units and the reference point. In some
embodiments, the change in the configuration of the corresponding
arm comprises a change in a length of the corresponding arm. In
some embodiments, the change in the configuration of the
corresponding arm comprises extending the corresponding arm.
[0006] In some embodiments, the processor is configured to
determine a change in an angular velocity of a rotor of the at
least one of a plurality of propulsion units. In some embodiments,
the rotor is distinct from a rotor of the at least one of a
plurality of propulsion units.
[0007] In some embodiments, the input is further configured to
receive information from at least one sensor on the unmanned aerial
vehicle for determining the change in the configuration of the
corresponding arm. In some embodiments, wherein the processor is
configured to determine the change in the configuration of the at
least one arm based on the information from the at least one
sensor. In some embodiments, the information from the at least one
sensor comprises at least one of a roll angle, pitch angle, yaw
angle, roll angle velocity, pitch angle velocity and yaw angle
velocity.
[0008] In some embodiments, each propulsion unit coupled to a
corresponding one of the plurality of arms comprises a rotor, and
wherein the processor is further configured to determine a
corresponding angular velocity for each rotor. In some embodiments,
wherein the processor is configured to set each corresponding
angular velocity greater than a threshold angular velocity to a new
angular velocity, wherein the new angular velocity is the threshold
angular velocity. In some embodiments, the processor is configured
to determine a length of the at least one arm using the new angular
velocity.
[0009] In some embodiments, the first signal comprises information
received from at least one of a gyroscope, inertial measurement
unit, mass sensor, accelerometer and GPS sensor.
[0010] In some embodiments, the processor is further configured to
determine change in configuration of more than one of the plurality
of arms.
[0011] In some embodiments, the first signal indicates a change in
configuration of a payload of the unmanned aerial vehicle. In some
embodiments, the first signal comprises a signal indicating at
least one of a change in mass of the payload and a redistribution
of mass of the payload. In some embodiments, the first signal
comprises a signal indicating an extension or retraction of a
telescoping feature of the payload. In some embodiments, the first
signal comprises a signal indicating an extension or retraction of
at least one of a telescoping arm, telescoping lens unit and
telescoping nozzle of the payload.
[0012] According to some aspects, a method of controlling an
unmanned aerial vehicle can include receiving a first signal
indicating a change in a center of gravity of the unmanned aerial
vehicle, wherein the unmanned aerial vehicle comprises a plurality
of arms, at least one of the plurality of arms extending from a
central body, and a plurality of propulsion units, at least one of
the plurality of propulsion units being positioned on a
corresponding arm at a distance from a reference point on the
central body; and determining, in response to the change in the
center of gravity, a change in a configuration of at least one of
the plurality of arms of the unmanned aerial vehicle to change the
distance of the at least one of the plurality of propulsion units
from the reference point to counter the change in the center of
gravity.
[0013] In some embodiments, the change in the configuration of the
at least one arm is configured to position the at least one of the
plurality of propulsion units at a second distance further away
from the reference point on the central body to counter the change
in the center of gravity. In some embodiments, the reference point
is at a center of the central body. In some embodiments,
determining comprises determining a change in a length of the at
least one arm.
[0014] In some embodiments, the method includes determining a
change in an angular velocity of a rotor of a propulsion unit
coupled to the at least one arm.
[0015] In some embodiments, the method includes receiving
information from at least one sensor on the unmanned aerial vehicle
for determining the change in the configuration of the at least one
arm. In some embodiments, determining comprises determining the
change in the configuration of the at least one arm based on the
information from the at least one sensor. In some embodiments,
receiving the information from the at least one sensor comprises at
least one of a roll angle, pitch angle, yaw angle, roll angle
velocity, pitch angle velocity and yaw angle velocity.
[0016] In some embodiments, the first signal comprises information
received from at least one of a gyroscope, inertial measurement
unit, mass sensor, accelerometer and GPS sensor.
[0017] In some embodiments, the first signal indicates a change in
configuration of a payload of the unmanned aerial vehicle. In some
embodiments, the first signal comprises a signal indicating at
least one of a change in mass of the payload and a redistribution
of mass of the payload. In some embodiments, the first signal
comprises a signal indicating an extension or retraction of a
telescoping feature of the payload. In some embodiments, the first
signal comprises a signal indicating an extension or retraction of
at least one of a telescoping arm, telescoping lens unit and
telescoping nozzle of the payload.
[0018] According to some aspects, a controller for controlling an
unmanned aerial vehicle, can include an input for receiving a first
signal comprising information relating to a payload of the unmanned
aerial vehicle, wherein the unmanned aerial vehicle comprises a
plurality of arms, at least one of the plurality of arms extending
from a central body, and a plurality of propulsion units, at least
one of the plurality of propulsion units being positioned on a
corresponding arm at a distance from a reference point on the
central body; and a memory for storing predetermined values; and a
processor configured to retrieve a predetermined value from the
memory based on the first signal for determining a change in the
distance of the at least one of the plurality of propulsion units
from the reference point.
[0019] In some embodiments, the input is further configured to
receive information indicating an absence of the payload. In some
embodiments, the input is further configured to receive information
indicating a payload type. In some embodiments, the input is
further configured to receive information of a configuration state
of the payload.
[0020] In some embodiments, the memory comprises a table, and the
process is configured to retrieve the predetermined value from the
table of the memory. In some embodiments, in the predetermined
value indicates the distance of the at least one of the plurality
of propulsion units from the reference point. In some embodiments,
the predetermined value indicates a length of the corresponding arm
to which the at least one of the plurality of propulsion units is
coupled.
[0021] In some embodiments, the processor is further configured to
perform a calculation using the predetermined value and generate a
second signal for changing a configuration of the corresponding arm
based on a result of the calculation.
[0022] In some embodiments, the input is configured to receive the
first signal from at least one sensor on the unmanned aerial
vehicle. In some embodiments, the input is configured to receive
the first signal from a user input.
[0023] According to some aspects, a method of controlling an
unmanned aerial vehicle can include receiving a first signal
comprising information relating a payload of the unmanned aerial
vehicle, wherein the unmanned aerial vehicle comprises a plurality
of arms, at least one of the plurality of arms extending from a
central body, and a plurality of propulsion units, at least one of
the plurality of propulsion units being positioned on a
corresponding arm at a distance from a reference point on the
central body. The method can include retrieving a predetermined
value from a memory of the unmanned aerial vehicle based on the
information of the first signal; and generating a second signal for
changing the configuration of the corresponding arm to change the
distance of the at least one of the plurality of propulsion units
from the reference point based on the predetermined value.
[0024] In some embodiments, receiving the first signal comprises
receiving information indicating an absence of the payload. In some
embodiments, receiving the first signal comprises receiving
information indicating a payload type. In some embodiments,
receiving the first signal comprises receiving information of a
configuration state of the payload.
[0025] In some embodiments, retrieving the predetermined value
comprises retrieving a value indicating a length of the
corresponding arm. In some embodiments, receiving the first signal
comprises receiving the first signal from at least one sensor on
the unmanned aerial vehicle
[0026] In some embodiments, receiving the first signal comprises
receiving the first signal from a user input.
[0027] In some embodiments, the method can include performing a
calculation using the predetermined value and generating the second
signal for changing the configuration of at the corresponding arm
comprises generating a signal based on a result of the
calculation.
[0028] In some embodiments, generating the second signal for
changing the configuration of at least one arm of the plurality of
arms comprises generating a signal comprising an instruction to
change a length of the at least one arm.
[0029] According to some aspects, a unmanned aerial vehicle can
include a central body; a plurality of arms, at least one of the
plurality of arms extending outwardly from the central body; and a
plurality of propulsion units, the plurality of propulsion units
being coupled to corresponding arms, and a distance of at least one
of the plurality of propulsion units from a reference point on the
central body being adjustable by manipulating a configuration of at
least one of the corresponding arms in response to a change in a
center of gravity of the unmanned aerial vehicle.
[0030] In some embodiments, the configuration of at least one
corresponding arms comprises a length of the at least one
corresponding arms. In some embodiments, the at least one
corresponding arms is extendable.
[0031] In some embodiments, wherein each of the propulsion units
comprises a rotor, and the distance of the at least one of the
plurality of propulsion units from the reference point is a
distance from a rotational axis of the rotor to the reference
point.
[0032] In some embodiments, the unmanned aerial vehicle can include
a plurality of rotors and a plurality of sets of rotor blades,
wherein each of the propulsion units comprises a corresponding
rotor, and each of sets of rotor blades is coupled to a
corresponding rotor, and wherein an angular velocity of at least
one set of rotor blades is adjustable in response to the change in
the center of gravity of the unmanned aerial vehicle.
[0033] In some embodiments, the unmanned aerial vehicle can include
a payload, wherein the change in the center of gravity of the
unmanned aerial vehicle comprises a change in a configuration of
the payload. In some embodiments, the payload comprises a
telescoping feature.
[0034] According to some aspects, an unmanned aerial vehicle (UAV),
can include a central body; a plurality of arms, at least one of
the plurality of arms extending outwardly from the central body;
and a plurality of propulsion units, each of the plurality of
propulsion units being coupled to a corresponding arm, and a
configuration of at least one of the corresponding arms being
adjustable in response to a change in a center of gravity of the
UAV.
[0035] According to some aspects, a method of operating an unmanned
aerial vehicle can include receiving a first signal indicating a
change in a center of gravity of the unmanned aerial vehicle,
wherein the unmanned aerial vehicle comprises a central body, a
plurality of arms, at least one of the plurality of arms extending
outwardly from the central body, and a plurality of propulsion
units, the plurality of propulsion units being coupled to
corresponding arms. The method can include adjusting a distance of
at least one of the plurality of propulsion units from the central
body by manipulating a configuration of at least one of the
corresponding arms in response to the change in a center of gravity
of the unmanned aerial vehicle.
[0036] In some embodiments, manipulating the configuration of at
least one corresponding arms comprises adjusting a length of the at
least one corresponding arms. In some embodiments, manipulating the
configuration of least one corresponding arms comprises extending
the at least one corresponding arms.
[0037] In some embodiments, each of the propulsion units comprises
a rotor, and wherein adjust the distance comprises adjusting a
distance from a rotational axis of the rotor to the central
body.
[0038] In some embodiments, the unmanned aerial vehicle further
comprises a plurality of rotors and a plurality of sets of rotor
blades, wherein each of the propulsion units comprises a
corresponding rotor, and each of sets of rotor blades is coupled to
a corresponding rotor, and further comprising adjusting an angular
velocity of at least one set of rotor blades in response to the
change in the center of gravity of the unmanned aerial vehicle.
[0039] In some embodiments, the unmanned aerial vehicle further
comprises a payload, and wherein manipulating a configuration of at
least one of the corresponding arms in response to the change in a
center of gravity of the unmanned aerial vehicle comprises
manipulated the configuration in response to a change in a
configuration of the payload.
INCORPORATION BY REFERENCE
[0040] All publications, patents, and patent applications mentioned
in this specification are herein incorporated by reference to the
same extent as if each individual publication, patent, or patent
application was specifically and individually indicated to be
incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the present disclosure will be obtained
by reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the disclosure
are utilized, and the accompanying drawings of which:
[0042] FIG. 1 is a schematic diagram showing an example of forces
which can be exerted upon a UAV, according to some embodiments
[0043] FIG. 2 shows schematic diagrams of a UAV comprising one or
more arms in various configuration states, according to some
embodiments.
[0044] FIG. 3 shows schematic diagrams of a UAV comprising a
payload which has a telescoping arm, according to some
embodiments.
[0045] FIG. 4 is a flowchart of a method for changing the length of
one or more arms of the UAV during flight, according to some
embodiments.
[0046] FIG. 5 is a flowchart of a method for determining a change
in the length of one or more arms to counter a shift in the center
of gravity of a UAV, according to some embodiments.
[0047] FIG. 6 is a process flow diagram of an example of a process
for changing the configuration of one or more arms of a UAV prior
to flight, according to some embodiments.
[0048] FIG. 7 is a block diagram of an example of a system
configured to effect a change in the configuration of one or more
arms of a UAV, according to some embodiments.
[0049] FIG. 8 is a block diagram of a feedback loop for controlling
operation of a UAV, according to some embodiments.
[0050] FIG. 9 is a schematic diagram of an example of a movable
object including a carrier and a payload.
[0051] FIG. 10 is a schematic diagram of an example of a system for
controlling a movable object.
DETAILED DESCRIPTION
[0052] The present disclosure provides improved systems and methods
for operating a movable vehicle, including an unmanned vehicle,
such as an unmanned aerial vehicle (UAV). A configuration of one or
more components of a UAV may be adjusted in response to or in
anticipation of a change in the center of gravity of the UAV. The
center of gravity of the UAV may change due to the coupling,
decoupling or change in configuration of a payload of the UAV. The
configuration of one or more components of the UAV may be adjusted
such that the center of thrust of the UAV can be shifted in
response to or in anticipation of the change in the center of
gravity of the UAV. The configuration of one or more components of
the UAV may be adjusted so as to position of the center of thrust
of the UAV at or proximate to the new center of gravity. As
described herein, a component of the UAV may be an arm of the UAV
and the length of the arm may be adjusted to position the center of
thrust of the UAV at or proximate to the new center of gravity. The
configuration of one or more components may be adjusted prior to
flight, such as when the UAV is on a landing surface, and/or during
flight. Adjustment in the configuration of the one or more
components may be performed repeatedly throughout the flight to
counter changes in the center of gravity of the UAV.
[0053] A UAV as described herein may comprise a plurality of arms
extending outwardly from a central body. Each of the plurality of
arms can be coupled to one or more propulsion units. Each
propulsion unit may comprise a rotor, and a set of rotor blades can
be coupled to each of the rotors. A distance from one or more of
the rotors, and the set of rotor blades coupled to each of the one
or more rotors, to the central body can be adjusted to shift the
center of thrust of the UAV. For example, the distance from the
rotational axis of a rotor to the central body can be adjusted so
as to shift the center of thrust of the UAV. The aforementioned
distance can be defined relative to any point on the central body.
In some instances, a point on the central body may serve as a
reference point from which the distance is defined. The reference
point may be located, for example at the center of the central
body. Alternatively, the reference point may be located at an edge
of the central body. In some cases, the aforementioned distance can
be defined relative to one or more planes. The one or more planes
may intersect the central body. The planes may be orthogonal to one
another. For example, a yaw axis, pitch axis, and roll axis of the
central body of the UAV may lie on orthogonal planes intersecting
the central body. In some embodiments, the one or more planes need
not be orthogonal to one another. For example, the planes may be
oblique to one another.
[0054] In some embodiments, a configuration of a corresponding arm
to which the one or more rotors is coupled can be changed to change
the distance between a rotor and the central body. For example, one
or more of the plurality of arms coupled to the rotors can be
configured to be extendable or retractable. The one or more arms
may be extended or retracted to position the corresponding rotors
further away from or closer to the central body of the UAV,
respectively, such that the center of thrust of the UAV can be
shifted to counter the shift in the center of gravity of the UAV.
In some embodiments, the angular velocity of one or more sets of
rotor blades may be adjusted, in combination with the length of the
one or more arms, to counter the shift in the center of gravity of
the UAV. For example, the angular velocities of the rotor blades
and the lengths of the arms can be adjusted (in various
combinations) to shift the center of thrust in accordance with the
shift in center of gravity of the UAV.
[0055] In some embodiments, (1) the length of the one or more arms
and/or (2) the angular velocity of one or more sets of rotor blades
of the UAV, can be adjusted while the UAV is in flight. For
example, the length of the one or more arms and/or the angular
velocity of the one or more sets of rotor blades can be adjusted
during flight prior to, during, or after a shift in the center of
gravity of the UAV, to counter the shift in center of gravity. A
shift in the center of gravity of the UAV may occur during flight,
for example, due to a transformation in the configuration of a
payload. A transformation in the configuration of the payload may
occur during flight due to a change in the distribution of mass of
the payload, and/or an increase or decrease in the mass of the
payload, as described in further details herein. The length of the
one or more arms and/or the angular velocity of the one or more
sets of rotor blades can be adjusted prior to, during, or after the
change in the configuration of the payload to shift the center of
thrust of the UAV.
[0056] In some embodiments, the length of one or more arms coupled
to a rotor can be adjusted prior to flight. The adjustment in the
length of the one or more arms can be performed prior to flight in
anticipation of a change in the center of gravity due to the
presence of a payload or a change in the configuration state of the
payload. The length of one or more arms coupled to a rotor can be
adjusted prior to flight to facilitate providing a center of thrust
at or proximate to the center of gravity of the UAV when the UAV is
in flight. In some embodiments, prior to flight, one or more
processors onboard the UAV may receive information relating to the
type and/or configuration state of the payload, and the processors
may determine an adjustment in the length of one or more arms of
the UAV based on values stored in a memory table using the
information of relating to the type and/or configuration state of
the payload. For example, values stored in the memory may comprise
values indicating the length of each of the arms of the UAV
corresponding to different types of payloads and/or different
payload configuration states. In some embodiments, values stored in
the memory may comprise values indicating the change in length of
one or more arms for corresponding payload types and/or payload
configuration states.
[0057] Adjustment in the length of one or more arms of the UAV to
provide a desired shift in the center of thrust of the UAV may
reduce or eliminate the need to significantly change the angular
velocity of one or more rotors to shift the center of thrust of the
UAV. The rate at which the angular velocity of a rotor can be
changed in response to shifts in the center of gravity, and/or the
magnitude of change in the angular velocity of a rotor that can be
made, may be hampered or limited by one or more electrical
components. For example, the ability of one or more electrical
components to deliver current to a rotor to effectuate the changes
in angular velocity may be limited by one or more properties of the
electrical component. A current supply may be limited, for example,
due to a material composition of such electrical components.
Materials used for such electrical components may exhibit
degradation and/or damage above certain current thresholds, for
example limiting the power supply to the UAV rotors, thereby
adversely affecting flight stability of the UAV. Relying only upon
the change in angular velocity of one or more rotors may thereby
reduce the ability of the UAV to shift its center of thrust to
counter a shift in the center of gravity. A UAV demonstrating a
reduced ability to shift its center of thrust may be unstable
during flight. A UAV with a reduced ability to adjust its center of
thrust may also contribute to uneven wear of one or more of its
components, including one or more of its propulsion units. Reliance
only upon the angular velocity of one or more rotors may contribute
to increased consumption of battery power.
[0058] One or more systems and/or methods described herein
utilizing a change in the length of one or more arms to shift the
center of thrust of the UAV can provide a UAV with improved ability
to position the center of thrust at or proximate to the center of
gravity of the UAV. Improved ability to position the center of
thrust at or proximate to the center of gravity of the UAV can
provided improved UAV stability during flight, and reduced uneven
wear on one or more components of the UAV and/or reduced rate of
battery power consumption.
[0059] It will be understood that while embodiments in the present
disclosure may be primarily described with reference to unmanned
aerial vehicles which are quadcopters, the methods and/or systems
described herein are also applicable to unmanned aerial vehicles,
such as multi-rotors, having a different number of rotors. The
systems and/or methods described herein may be applied to unmanned
aerial vehicles with more than four or fewer than four rotors. In
some embodiments, the methods and/or systems described herein may
be applied to tricopters, pentacopter, hexacopters and/or
octocopters.
[0060] FIG. 1 is a schematic diagram showing an example of the
forces which can be exerted upon a UAV 100, according to some
embodiments. The UAV 100 is shown as a quadcopter in FIG. 1,
comprising four propulsion units. Each of the four propulsion units
can comprise a rotor, and a corresponding set of rotor blades
coupled to each of the rotors. A rotor and a corresponding set of
rotor blades can be positioned at a first rotor position 102,
second rotor position 104, third rotor position 106 and fourth
rotor position 108. Each of the rotors, and the sets of rotor
blades coupled to the rotors, can be at an initial distance from an
initial center of gravity of the UAV 100. For example, the first
rotor position 102, second rotor position 104, third rotor position
106 and fourth rotor position 108 can be on the rotational axis of
each of the respective rotors, such that the distance between the
rotational axis of the first rotor, second rotor, third rotor, and
fourth rotor, and an initial center of gravity 110 are l.sub.1,
l.sub.2, l.sub.3, and l.sub.4, respectively. Each set of rotor
blades and corresponding rotor may rotate about a rotational axis,
such that the distance between the rotational axes of the first,
second, third and fourth set of rotor blades, and an initial center
of gravity 110 are given by l.sub.1, l.sub.2, l.sub.3, and l.sub.4,
respectively.
[0061] Each of the four rotors may be supported on and/or coupled
to a corresponding arm of the UAV 100. For example, the UAV 100 may
have four arms extending outwardly from a central body. Each of the
four rotors can be coupled to a corresponding arm of the UAV 100
such that the rotors are positioned at a desired distance from the
central body. Torque can be applied to each of the four rotors to
rotate each of the sets of rotor blades around a corresponding
rotational axis so as to provide an upward force, or thrust, along
the rotational axis. The thrust which can be generated by spinning
the sets of rotor blades are shown as F.sub.1, F.sub.2, F.sub.3 and
F.sub.4 in FIG. 1. Angular velocity of each of the sets of rotor
blades can be adjusted to control the thrust F.sub.1, F.sub.2,
F.sub.3 and F.sub.4 exerted upon the UAV 100.
[0062] A torque in the direction of rotation of each of the rotors
may be exerted upon the UAV 100 due to rotation of each of the
rotors around the corresponding rotational axis. The torque exerted
upon the UAV 100 by each of the four sets of rotors is shown as
T.sub.1, T.sub.2, T.sub.3 and T.sub.4, respectively. As shown in
FIG. 1, adjacent rotors can be rotated in opposing directions such
that the corresponding torques are in opposite directions. During
flight, F.sub.1, F.sub.2, F.sub.3, F.sub.4, T.sub.1, T.sub.2,
T.sub.3 and T.sub.4 can be adjusted to control the attitude of the
UAV 100, for example by adjusting the angular velocity of the
corresponding rotor.
[0063] The UAV 100 can have an initial center of gravity at its
initial center of gravity position 110, and the magnitude of the
force exerted by gravity upon the UAV 100 is shown as F.sub.g1. In
some cases, the initial center of gravity position 110 can be at an
intersection of a first line extending between the first rotor and
the third rotor, such as between the rotational axes of the first
and third rotors, and a second line extending between the second
rotor and the fourth rotor, such as between the rotational axes of
the second and fourth rotors. In some embodiments, the first and
second lines can be orthogonal to one another. In some embodiments,
the first and second lines bisect each other such that the initial
center of gravity position 110 is at a midpoint on both the first
and second lines. In some embodiments, the initial center of
gravity position 110 of the UAV 100 can be at the center of the
central body. In some embodiments, the initial center of gravity
position 110 of the UAV 100 can be at a position other than the
center of the central body.
[0064] In some embodiments, the center of gravity of the UAV 100
can shift from the initial center of gravity position 110. For
example, as shown in FIG. 1, the center of gravity of the UAV 100
can change from its initial center of gravity position 110 to a
second center of gravity position 112, and the force exerted upon
the UAV 100 after the shift in center of gravity of the UAV 100 is
shown as F.sub.g2. In some embodiments, a shift in the center of
gravity of the UAV 100 can be accompanied by a change in mass of
the UAV 100 such that F.sub.g1 and F.sub.g2 are different. In some
embodiments, a shift in the center of gravity of the UAV 100 is not
accompanied by a change in mass of the UAV 100, such that F.sub.g1
is equal to F.sub.g2. The change in center of gravity of the UAV
100 can occur due to a change in configuration of one or more
components of the UAV 100. For example, a change in the center of
gravity can occur due to coupling or decoupling (e.g., attachment
or release) of a payload from the UAV 100. In some embodiments, a
shift in the center of gravity of the UAV 100 can occur due to a
change in configuration of a payload of the UAV 100. For example,
the payload may comprise a telescoping feature which may be
extended or retracted, and that can change the configuration of the
payload. As shown in FIG. 1, according to some embodiments, a
telescoping feature of the payload may be extended a length
.DELTA.l.sub.g such that a distal portion of the telescoping
feature is at an extended position 114. This extension of the
telescoping feature cause the initial center of gravity position
110 of the UAV 100 to shift to the second center of gravity
position 112.
[0065] The center of thrust of the UAV 100 (not shown) may be
adjusted to counter the shift in the center of gravity of the UAV
100. In some embodiments, the initial position for the center of
thrust of the UAV 100 may be at or proximate to the initial center
of gravity position 110. The center of thrust of the UAV 100 may be
shifted from its initial position to a second position to counter
the shift in the center of gravity. For example, the center of
thrust of the UAV 100 may be shifted to a second position such that
its second position is at or proximate to the second center of
gravity position 112. The position of one or more of the first,
second, third and fourth rotors can be adjusted to shift the center
of thrust of the UAV 100. For example, one or more of the first,
second, third and fourth rotors can be positioned closer to or
further away from the central body of the UAV 100 to shift the
center of thrust. In some embodiments, the positions of one or more
of the rotors can be adjusted relative to a reference point on the
central body. The reference point may be located anywhere on the
central body. For example, the reference point can be at the center
of the central body. In some alternative embodiments, the reference
point may be located external to the central body. One or more of
the lengths l.sub.1, l.sub.2, l.sub.3, and l.sub.4 can be adjusted
to shift the center of thrust. In some embodiments, the length of
one or more arms of the UAV 100 can be adjusted to achieve to
desired change in one or more of l.sub.1, l.sub.2, l.sub.3, and
l.sub.4. For example, the one or more arms of the UAV 100 can be
extended or retracted to place one or more corresponding rotors at
the desired positions.
[0066] Referring to FIG. 1, as an example, the first and second
rotors can be repositioned to achieve the desired shift in the
center of thrust of the UAV 100. For example, the lengths l.sub.1
and can be changed to counter the change of the center of gravity
from the first center of gravity position 110 to the second center
of gravity position 112. The lengths l.sub.1 and l.sub.2 can be
changed by .DELTA.l.sub.1 and .DELTA.l.sub.2, respectively, such
that the center of thrust of the UAV 100 can be positioned at or
proximate to the second center of gravity position 112. A
configuration of the corresponding arms to which the first and
second rotors are coupled can be changed to reposition the first
and second rotors, such as by extending each of the corresponding
arms. A change to the configuration of one or more arms can be made
prior to and/or during flight. For example, the change to the
configuration can be made during flight prior to, during, or after
the change in the center of gravity has occurred. In some
embodiments, the change to the configuration can be made prior to
flight based on information relating to the type and/or
configuration state of the payload.
[0067] A configuration of one or more arms of the UAV 100 can be
changed to shift the center of thrust of the UAV 100, in order to
counter a shift in the center of gravity of the UAV 100. The
configuration of the one or more arms can be changed such that that
the center of thrust of the UAV 100 can be at or proximate to the
new center of the gravity. Changing the configuration of the arms
to change the center of thrust of the UAV 100 can reduce
operational burden on the rotors (and rotor blades). This can
advantageously provide a UAV 100 demonstrating increased uniformity
in wear of components of the UAV 100, for example such that none of
the rotors exhibit increased wear relative to other rotors of the
UAV 100. Reduced burden on the rotors (and rotor blades) may
provide reduced consumption of battery power, and/or improved
stability during flight.
[0068] As previously mentioned, a change in the center of gravity
of UAVs can occur due to coupling or decoupling of a payload,
and/or a change in configuration of a payload. In some embodiments,
a payload can be coupled to or decoupled from a UAV prior to
flight. For example, the configuration of one or more arms of the
UAV can be adjusted prior to flight to account for the coupling or
decoupling of the payload. In some embodiments, a change in the
configuration of the payload can occur due to a change in the
distribution of mass of the payload during flight. In some
embodiments, a change in the distribution of mass of the payload
may result from movement of the content of the payload. The content
may be a solid or a fluid. In some embodiments, the payload may be
carrying content that becomes rearranged during flight, such as
shifting around of items in a container (e.g., a sack, a bottle,
and/or a box) carried by the payload.
[0069] In some embodiments, the change in distribution of mass of
the payload may be due to a change in a configuration state of the
payload. The change in the configuration state of a telescoping
feature of the payload may result in a change in the center of
gravity of the UAV. For example, a telescoping feature of the
payload can extend or retract during flight, changing the
distribution of mass of the payload, and thereby shifting the
center of gravity of the UAV. In some embodiments, the telescoping
feature can be a telescoping arm, or a foldable arm. For example, a
foldable arm in an extended state may be configured to carry one or
more instruments at a distal portion away from the central body of
the UAV to deliver the one or more instruments to a target. The
foldable arm may be retracted when the UAV is on a landing surface
and/or when the UAV is in flight traveling to a target destination,
and can be extended to deliver the one or more instruments to a
target after the UAV reaches the target destination. After delivery
of the instrument to the target and/or completion of the task using
the one or more instruments at the target destination, the foldable
arm may be retracted. The foldable arm may be folded into a reduced
profile configuration when not in use to facilitate movement and/or
storage of the UAV. A variety of instruments may be delivered by
the foldable arm, including but not limited to, cleaning
instruments, cutting instruments, and/or containers.
[0070] In some embodiments, the telescoping feature may be a part
of an imaging device comprising an extendable lens unit, such as an
extendable lens barrel. For example, the payload may comprise a
camera or other imaging device comprising an extendable lens unit.
The lens unit may be extended or retracted to change the focal
length of the lens unit so as to facilitate imaging of targets. The
extension and/or retraction of the lens unit can shift the
distribution of mass of the payload, thereby shifting the center of
gravity of the UAV. In some embodiments, a telescoping feature may
comprise a retractable spray nozzle, for example for use in various
agricultural applications for delivering one or more chemical
compounds to any number of crops, such as on UAVs used as crop
dusters. For example, the retractable nozzle may be extended after
the UAV reaches the target destination for delivering the one or
more chemical compounds to the target destination, and may be
subsequently retracted after completion of the delivery. Changes in
configuration state of the payload other than extension and
retraction of a telescoping feature may also result a shift in the
center of gravity of a UAV, including a rotation of one or more
components of the payload, and/or a translational movement of the
payload.
[0071] In some embodiments, a change in the configuration of the
payload can occur due to a gain and/or loss in the mass of the
payload. For example, content of the payload may be increased
and/or decreased during flight. In some embodiments, the content of
the payload may be dispensed and/or refilled during flight. In some
embodiments, the payload can pick up or drop off a portion or all
of its content. The gain and/or loss of mass of the payload may
cause a shift in the center of gravity of the UAV such that the
configuration of one or more arms of the UAV coupled to a rotor can
be changed to counter the shift in the center of gravity, such as
by extending or retracting the one or more arms.
[0072] Referring to FIG. 2, schematic diagrams of a UAV 200
comprising one or more arms in various configuration states are
shown. In Part A of FIG. 2, the UAV 200 is shown in an initial
state, or a first state. The UAV 200 may be landed on a surface or
in flight in its initial state, including in flight and in motion
or in flight and hovering at a spot. The UAV 200 can have a central
body 202, and a plurality arms extending outwardly form the central
body 202. The UAV 200 may be a quadcopter, including a first arm
204, a second arm 206, a third arm 208 and a fourth arm 210,
extending outwardly from the central body 202. Each of the arms
204, 206, 208 and 210 may comprise a corresponding propulsion unit
coupled to the arm. Each propulsion unit may comprise a rotor to
which a set of rotor blades are coupled. For example, a first set
of rotor blades 214, second set of rotor blades 216, third set of
rotor blades 218 and fourth set of rotor blades 220 may be coupled
to a rotor on each of the first arm 204, second arm 206, third arm
206 and fourth arm 208, respectively. For illustrative purposes,
the central body 202 of the UAV 200 is shown to have a square or
substantially square shape, each of the four arms 204, 206, 208 and
210 extending outwardly from a connection portion between adjacent
sides of the square. The central body 202 may have other suitable
shapes, such as a rectangular shape, and/or a rounded shape. The
arms may extend from the central body 202 at positions other than
from the connection portion between adjacent lateral sides.
[0073] The UAV 200 in its first state can have an initial center of
gravity at CG.sub.1. CG.sub.1 can be at a position on central body
202 of the UAV 200. In some embodiments, the center of thrust of
the UAV 200 can be at or proximate to CG.sub.1 in its first state.
As described herein, adjusting the angular velocity of one or more
rotors of a UAV 200 can be used to adjust the center of thrust of
the UAV 200. Part A of FIG. 2 shows a top down schematic diagram of
a zone 222 within which the center of thrust of the UAV 200 can be
adjusted by changing the angular velocity of one or more rotors of
the UAV 200, without changing the length of any of the arms 204,
206, 208 and 210. For example, the zone 220 may comprise a lateral
boundary having sides which extend between the rotational axes of
adjacent rotors, such that adjusting the angular velocity of one or
more rotors may allow shifting of the center of thrust of the UAV
200 to a point within the zone 222, or a point on the boundary of
the zone 222.
[0074] Part B of FIG. 2 shows the UAV 200 in a second state. In
Part B of FIG. 2, the center of gravity of the UAV 200 in the
second state is shown as having shifted to a second position
CG.sub.2. As described herein, a shift in the center of gravity can
be due to coupling or decoupling of a payload and/or a change in
configuration of a payload of the UAV 200. One or more of the
rotors of the UAV 200 can be repositioned in response to the change
in the center of gravity. As shown in Part B of FIG. 2, the
configuration of an arm can be changed, such as by extending the
length of an arm of the UAV 200, in response to the shift in the
center of gravity of the UAV 200. For example, in the second state,
the length of the first arm 204 of the UAV 200 may be extended to
shift the center of thrust of the UAV 200 in response to the shift
in the center of gravity of the UAV 200.
[0075] Extension of one or more arms of the UAV 200 may expand the
zone within which the center of thrust of the UAV 200 can be
shifted. For example, as shown in Part B of FIG. 2, the zone 224
within which the center of thrust of the UAV 200 may be shifted
while the UAV 200 is in its second state may be larger than the
zone 222 as described with reference to Part A. The zone 224 may
comprise a lateral boundary comprising sides extending between
rotational axes of adjacent rotors of the UAV 200, including
between the rotational axis of the rotor coupled to extended first
arm 204 and rotors coupled to corresponding adjacent arms 206, 210.
The zone 224 can encompass a space larger than that of the zone 220
described with reference to Part A of FIG. 2, for example, as the
rotor coupled to the extended first arm 204 is positioned further
away from the central body 202 of the UAV 200. The second center of
gravity position CG.sub.2 may be outside of the zone 222 of the UAV
200 in its initial state, while remaining within the zone 224 of
the UAV 200 in the second state. Extending the first arm 204 may
facilitate adjusting the position of the center of thrust of the
UAV 200 such that it is positioned at or proximate to the third
center of gravity position CG.sub.2. In some embodiments, extending
one or more arms of the UAV 200 may expand the zone within which
its center of thrust can be shifted, improving the ability of the
UAV 200 to respond to changes in its center of gravity.
[0076] In some embodiments, the configuration of more than one of
the arms of the UAV 200 can changed in response to a shift in the
center of gravity of the UAV 200. For example, two of the arms of
the UAV 200 may be extended for adjusting the center of thrust of
the UAV 200 in response to a shift in the center of gravity of the
UAV 200. Part C of FIG. 2 shows the UAV 200 in a third state. In
Part C of FIG. 2, the center of gravity of the UAV 200 is shown to
have shifted to a third center of gravity position CG.sub.3. The
configuration of two of the arms of the UAV 200, such as the third
arm 208 and fourth arm 210 can be adjusted to counter the shift in
the center of gravity. The third arm 208 and fourth arm 210 may be
extended to reposition the corresponding rotors coupled to the
third arm 208 and the fourth arm 210 in response to the change in
the center of gravity. For example, the third arm 208 and fourth
arm 210 may be extended to reposition the corresponding rotors such
that the third center of gravity position CG.sub.3 can be within
the zone 226 within which the center of thrust of the UAV 200 can
be shifted. The zone 226 within which the center of thrust can be
positioned may comprise a lateral boundary having sides extending
between rotational axes of adjacent rotors, including rotors
coupled to the extended third arm 208 and fourth arm 210. Extending
the arms 208, 210 may facilitate adjusting the position of the
center of thrust of the UAV 200 such that it is positioned at or
proximate to the third center of gravity position CG.sub.3.
[0077] In some embodiments, one or more arms of the UAV 200 can be
further adjusted in response to a subsequent change in the center
of gravity of the UAV 200. For example, after retraction of an
extended telescoping feature of a payload, the one or more extended
arms of the UAV 200 may be retracted in response to the change of
the center of gravity of the UAV 200 back to the initial state. In
some embodiments, the angular velocity of one or more rotors of the
UAV 200 may be adjusted, in combination with a change in the length
of the one or more arms, to counter a shift in the center of
gravity of the UAV 200. In some embodiments, the one or more rotors
may be rotors coupled to the one or more extended or retracted
arms. In some embodiments, the one or more rotors are on one or
more other arms of the UAV 200.
[0078] FIG. 3 show schematic diagrams of a UAV 300 supporting a
payload 310 which has a telescoping arm 312. The UAV 300 may have
one or more features of other UAVs described herein. For example,
the UAV 300 may be a quadcopter comprising four arms 304 extending
from a central body 302, each of the arms 302 supporting a
corresponding rotor 306, and a set of rotor blades 308 coupled to
each of the rotors 306. As shown in Part A and Part B of FIG. 3,
the telescoping arm 312 may be extended or retracted. A cleaning
instrument 314 may be coupled to a distal portion of the
telescoping arm 312, for example for delivery of the cleaning
instrument 314 to a target destination (e.g., a dirty window). The
cleaning instrument 314 is shown for illustrative purposes. Any
number of other implements suited to the task for which the UAV 300
is applied may be carried by the telescoping arm 312. For example,
the telescoping arm 312 may assume a reduced profile configuration
during travel to and/or away from the target destination, such as
shown in Part A, for example to facilitate movement of the UAV 300.
The telescoping arm 312 may assume an extended configuration, such
as shown in Part B, prior to, including immediately prior to,
after, including immediately after, the UAV 300 has reached the
target destination, or as the UAV 300 is approaching the target
destination, so as to facilitate contact of the cleaning instrument
314 with one or more surfaces at the target destination.
[0079] The center of gravity of the UAV 300 may shift due to the
extension and/or retraction of the telescoping arm 312. Extension
or retraction of one or more arms 304 of the UAV 300, along with
adjustment in the angular velocity of one or more rotors 306
coupled to the arms of the UAV 300, can be used to shift the center
of thrust of the UAV 300 to counter the shift in the center of
gravity of the UAV 300. As shown in Part B, two of the four arms
304 of the UAV 300 extending from the side of the central body 302
on which the telescoping arm 312 is extended, can be lengthened to
reposition the rotors 306 coupled to the two arms 304. For example,
the rotors 306 at the distal portions of the two arms 304 can be
positioned further away from the central body 302 to facilitate the
shift in the center of thrust of the UAV 300.
[0080] One or more processors of a UAV can be configured to
determine the change in length of one or more arms of a UAV in
response to a shift in center of gravity of the UAV. Referring to
FIG. 4, a flowchart of an exemplary 400 for changing the length of
one or more arms of the UAV during flight is provided. In block
402, one or more processors of the UAV can receive a signal
indicating a change in the center of gravity of the UAV will occur,
is occurring or has occurred. In some embodiments, a signal
indicating a change in the center of gravity has occurred may
comprise information measured by and/or derived from values
measured by one or more sensors on the UAV, such as one or more
sensors configured to provide information relating to the position
and/or orientation of the UAV. For example, the processors may
receive information from a gyroscope, inertial measurement unit
(IMU), mass sensor, accelerometer, magnetometer, global positioning
system (GPS) receiver, combinations thereof, and/or the like. One
or more signals from the sensors of the UAV may provide attitude
information indicating that the UAV has experienced a shift in
position and/or orientation. In some embodiments, the signal
indicating a change in the center of gravity (i) will occur, (ii)
is occurring or (iii) has occurred may comprise a signal indicating
a change in the configuration of a payload carried by the UAV will
occur, is occurring or has occurred. In some embodiments, the
signal may comprise information relating to the configuration state
of the payload prior to and/or after the configuration change. For
example, the signal may include information indicating that a
telescoping feature of the payload will be, is being, or has been
extended or retracted, and information regarding the extent to
which the telescoping feature will be, is being, or has been
extended or retracted. In some embodiments, the signal may comprise
information relating to the gain or loss of mass by the payload. In
some embodiments, the signal may include information relating to
the redistribution of mass of content of the payload.
[0081] In response to the received signals from the one or more
sensors, the processors may perform various calculations to
determine the change in length of one or more arms. Referring back
to FIG. 4, in block 404, the processors can calculate a change in
the length of one or more arms of the UAV coupled to one or more
rotors. As described in further detail herein, the processors of
the UAV may receive various measurements from one or more sensors
on the UAV for use in the calculation of the change in the length
of the one or more arms. In block 406, the processors may send an
instruction signal to an actuator based on the calculated change in
the length of the one or more arms, so as to extend or retract the
one or more arms of the UAV to shift the center of thrust of the
UAV in response to the change in the center of gravity of the UAV.
The actuator for extending or retracting the one or more arms may
be a linear actuator. The linear actuator may be on the central
body and/or on the one or more arms. The linear actuator may be
configured to apply a linear force upon a portion of the one or
more arms to extend or retract the one or more arms. In some
embodiments, angular velocity of one or more of the rotors of the
UAV may be adjusted, in combination with the change in length of
the one or more arms, to shift the center of thrust of the UAV to
counter the change in the center of gravity. The center of thrust
of the UAV may be shifted in response to the shift in the center of
gravity of the UAV such that the center of thrust can be at or
proximate to the new center of gravity of the UAV.
[0082] Determination of the change in the length of one or more
arms of the UAV can be performed using equations which characterize
the translational and rotational motion of the UAV. The
translational motion of a UAV, such as a multi-rotor UAV, can be
characterized by equation (1), where {umlaut over (x)}, and {umlaut
over (z)}, are the translational acceleration of the UAV along the
x-axis, y-axis and z-axis in the world coordinate system,
respectively. m in equation (1) is the mass of the UAV and g is the
earth gravitational acceleration constant. F.sub.p is the thrust
provided by rotation of the rotor blades of the UAV. F.sub.p is
expressed in the body frame coordinate system of the UAV, and the
equation for characterizing F.sub.p is shown in equation (2). R is
the transform matrix for transforming coordinates in the body frame
coordinate system to coordinates in the world coordinate system, or
the inertial frame coordinate system. The equation for R is shown
in equation (3).
[ x y z ] = R F p m - [ 0 0 g ] = k m .times. i = 1 4 .times.
.omega. 2 .function. [ cos .times. .times. .PSI.sin.THETA.cos.PHI.
+ sin .times. .times. .PSI.sin.PHI. sin .times. .times.
.PSI.sin.THETA.cos .times. .times. .PHI. - sin .times. .times.
.PHI.cos .times. .PSI. cos .times. .times. .THETA.cos .times. .PHI.
] m - [ 0 0 g ] ( 1 ) F p = [ 0 0 k m .times. i = 1 4 .times.
.omega. 2 ] ( 2 ) R = [ cos .times. .times. .PSI.sin .times.
.THETA. .times. cos .times. .times. .PHI. + sin .times. .times.
.PSI.sin .times. .PHI. sin .times. .times. .PSI.sin .times. .THETA.
.times. cos .times. .times. .PHI. - sin .times. .times. .PHI.cos
.times. .PSI. cos .times. .times. .THETA.cos .times. .PHI. ] ( 3 )
##EQU00001##
[0083] In equation (2), k.sub.m is a constant coefficient for
relating angular velocity .omega. of the rotors to the output
thrust, and .omega..sub.i is the angular velocity of rotor i of the
UAV. In equation (3), .PHI. is the roll angle, or rotation of the
UAV around the x-axis, .THETA. is the pitch angle, or the rotation
of the UAV around the y-axis, and .PSI. is the yaw angle, or the
rotation of the UAV around the z-axis.
[0084] The rotational motion of the UAV around the x-axis, y-axis
and z-axis, or the roll, pitch, and yaw of the UAV, respectively,
can be characterized by equation (4). {umlaut over (.PHI.)} is the
roll angular acceleration, or the angular acceleration of the UAV
rotation around the x-axis. {umlaut over (.THETA.)} is the pitch
angular acceleration, or the angular acceleration of the UAV
rotation around the y-axis, and {umlaut over (.PSI.)} is the yaw
angular acceleration, or the angular acceleration of the UAV
rotation around the z-axis.
[ .PHI. .THETA. .PSI. ] = [ { l 4 .times. k m .times. .omega. 4 2 -
l 2 .times. k m .times. .omega. 2 2 + .THETA. . .times. .PSI. .
.function. ( l y - l z ) } / l x { l 3 .times. k m .times. .omega.
3 2 - l 1 .times. k m .times. .omega. 1 2 + .PHI. . .times. .PSI. .
.function. ( l z - l x ) } / l y { k d .times. .omega. 1 2 - k d
.times. .omega. 2 2 + k d .times. .omega. 3 2 - k d .times. .omega.
4 2 + .PHI. . .times. .THETA. . .function. ( l x - l y ) } / l z ]
( 4 ) ##EQU00002##
[0085] Equation (4) can be used to characterize the rotational
motion of a UAV with four sets of rotors coupled to four
corresponding arms, where is the distance between the rotational
axis of rotor i and the center of gravity of the UAV, and co, is
the angular velocity of rotor i, where i=1, 2, 3 and 4. {dot over
(.PHI.)}, {dot over (.THETA.)}, and {dot over (.PSI.)} are the
roll, pitch and yaw angular velocities of the UAV, or the angular
velocities of the UAV around the x-, y- and z-axis, respectively.
I.sub.x, I.sub.y, and I.sub.z are the moments of inertia along the
x-axis, the y-axis and the z-axis, respectively, of the UAV. In
some embodiments, I.sub.x, I.sub.y, and I.sub.z may be approximated
using predetermined constants. K.sub.d can be a constant
coefficient for relating the output torque of the rotors and
angular velocity .omega. of the rotors.
[0086] The equations described herein can be used to determine the
length to which one or more of the arms of the UAV are to be
adjusted and/or the extent of the change to the length of the one
or more arms. One or more processors of the UAV may receive one or
more measurements and/or one or more values derived from
measurements made by one or more sensors of the UAV as input to the
equations described herein. For example, the processors may receive
measurements for and/or derive values based on measurements
received for roll angle (.PHI.), pitch angle (.THETA.), yaw angle
(.PSI.), and angular velocities for .PHI., .THETA. and .PSI., from
one or more sensors on the UAV. In some embodiments, the processors
can receive information from one or more of a gyroscope, inertial
measurement unit (IMU), accelerometer, and mass sensor, GPS sensor,
combinations thereof, and/or the like. The processors may use such
measurements and/or values derived from such measurements in one or
more equations described herein for calculating a change in the
length of one or more arms of the UAV. In some embodiments, the
processors may use such measurements and/or values derived from
such measurements in equations described herein for calculating
both a change in the length of one or more arms of the UAV and a
change in the angular velocity of one or more rotors of the
UAV.
[0087] Referring to FIG. 5, a flowchart of another exemplary method
500 for determining a change in the length of one or more arms to
counter a shift in the center of gravity of a UAV during flight is
shown. In block 502, one or more processors of the UAV can receive
one or more measurements and/or one or more values derived from
measurements received from one or more sensors on the UAV. In some
embodiments, the one or more measurements may include one or more
of the pitch angle, roll angle and yaw angle of the UAV. In some
embodiments, the one or more measurements can include one or more
of the pitch angular velocity, roll angular velocity and yaw
angular velocity of the UAV. The one or more sensors may include,
for example, a gyroscope, inertial measurement unit (IMU),
accelerometer, and mass sensor, GPS sensor, combinations thereof,
and/or the like. In block 504, the processors can calculate the
angular velocity .omega..sub.i for each rotor of the UAV using the
one or more measurements and/or one or more values derived from
measurements received from the one or more sensors. The equations
characterizing the translational and rotational motion of the UAV
as described herein can be used to calculate the angular velocities
.omega..sub.i. Previously known values for the distances of the
rotational axes of each of the rotors from the center of gravity of
the UAV can be used for the calculations. For example, the angular
velocities .omega..sub.i for each of the rotors of a quadcopter,
where =1, 2, 3, 4, can be determined.
[0088] In block 506, the calculated angular velocity .omega..sub.i
values for each of the rotors can be compared to a threshold
angular velocity value .omega..sub.t. In some embodiments, the
threshold angular velocity value Wt can be selected based on
characteristics of one or more electrical components of the UAV.
The angular velocity of each of the rotors may be limited at least
in part by the ability to supply current to one or more electrical
components, such as to an electrical rotor for spinning the rotors.
In some embodiments, the value of Wt may be selected to avoid or
prevent excess load placed upon the one or more electrical
components. For example, Wt may be selected such that the current
supplied to a rotor remains below an upper current limit. In some
embodiments, the upper current limit may be a current above which
the one or more electrical components of the UAV may be damaged
and/or degraded, such as one or more electrical components for
supplying current to the rotor. In some embodiments, .omega..sub.t
may be selected to provide desired battery performance, for example
so as to provide reduced battery consumption. In some embodiments,
Wt can be about 500 radians/second. In other embodiments, Wt can be
greater than or less than 500 radians/second.
[0089] In block 508, if any of the calculated angular velocities
.omega..sub.i is greater than .omega..sub.t, the angular velocity
.omega..sub.i for each of the sets of rotor blades where
.omega..sub.i is greater than the predetermined angular velocity
threshold .omega..sub.t can be set to equal the predetermined
angular velocity threshold Wt. For example, each of the angular
velocity values .omega..sub.i greater than 500 radians/second may
be set to 500 radians/second. In block 510, the distance l.sub.i
can be recalculated to determine new values for each of l.sub.i
using the new angular velocity values (i.e., where .omega..sub.i
has been set to equal .omega..sub.t). In block 512, the processors
can initiate a control signal to set the new angular velocities for
those sets of rotor blades where the angular velocity was set to
wt, and to adjust the arm length for any affected arms based on the
new values for l.sub.i. For example, a control signal may be
generated to set the angular velocity of one or more rotors to 500
radians/second and to set the length of one or more arms to the
recalculated l.sub.i.
[0090] In block 514, if all of the angular velocity values
.omega..sub.i calculated in block 504 are less than or equal to Wt,
the processors can initiate a control signal to set the one or more
angular velocities for each of the rotors to the calculated values
.omega..sub.i, without changing the length of any of the arms of
the UAV. In some embodiments, as shown in block 516, the steps of
calculating .omega..sub.i and/or l.sub.i can be repeated any number
of times in response to additional or subsequent shifts in the
center of gravity of the UAV.
[0091] As described herein, in some embodiments, the length of one
or more arms of the UAV can be adjusted prior to flight. One or
more arms of the UAV coupled to one or more rotors may be extended
or retracted while on a landing surface in anticipation of a change
in the center of gravity of the UAV that would otherwise occur. For
example, a change in the center of gravity of the UAV may occur
after take-off due to the presence or absence of a payload and/or a
configuration state of the payload, which has not been accounted
for. For example, prior to flight, one or more processors of the
UAV may receive information indicating that a payload has been
detected or that a payload is absent, and/or that the configuration
state of a payload is different from a previously known state of
the payload. The processors can determine, based on the information
relating to the presence and/or configuration state of the payload,
whether the length of any arms of the UAV coupled to a propulsion
unit is changed, as well as the change to the length of the one or
more arms. In some embodiments, the length of the one or more arms
of the UAV may be adjusted prior to flight or after take-off to
facilitate positioning the center of thrust of the UAV at or
proximate to the center of gravity of the UAV.
[0092] Referring to FIG. 6, a flowchart of an exemplary method 600
is shown for changing the configuration of one or more arms of a
UAV prior to flight. In block 602, one or more processors of the
UAV can receive information regarding the absence of a payload, or
the type and/or configuration of a payload. In some embodiments,
the UAV may receive the information from one or more sensors on the
UAV indicating whether a payload is absent or present. For example,
the UAV may comprise various sensors to determine whether coupling
components of a payload are present within corresponding mating
components. If a payload is present, the processors may receive
from one or sensors information relating to the type and/or
configuration of the payload. In some embodiments, the processors
may be able to communicate with the payload such that the
processors can receive from the payload information regarding the
type and/or configuration state of the payload. In some
embodiments, the type and/or configuration of the payload may be
manually entered by a user through a user interface on the UAV, or
via a remote user terminal that is configured to control the
UAV.
[0093] In block 604, the processors can retrieve one or more
predetermined values for determining the change in the
configuration of one or more arms of the UAV, based on the
information received regarding the absence of a payload, or the
type and/or configuration of a payload. In some embodiments, the
predetermined values can comprise values indicating which one or
more arms are affected and the change to the configuration of the
affected arms, such as the change in length of the one or more
arms. In some embodiments, the one or more predetermined values can
be used in the calculations for determining the change in the
length of one or more arms. In some embodiments, the predetermined
values may be stored in a memory of the UAV, such as a table in
memory that is accessible by the processors. For example, in
response to information received regarding the absence, or the type
and/or configuration state of the payload, the UAV may select from
the table in the memory predetermined values indicating the length
of which one or more arms of the UAV should be adjusted and the
change in the length for the one or more arms. In some embodiments,
further calculations are performed using values stored in the
memory onboard the UAV to determine which of the one or more arms
are to be extended or retracted, and the change in the length of
the one or more arms. In block 606, an instruction signal can be
sent by the processors to an actuator for changing the
configuration of the one or more arms based on the predetermined
values.
[0094] One or more methods for changing the configuration of one or
more arms, and/or angular velocities of one or more rotors of a UAV
may be implemented using one or more systems as described herein.
FIG. 7 is a schematic diagram of an example of a system 700
configured to effect a change in the configuration of one or more
arms coupled to one or more corresponding rotors, and/or a change
in the angular velocities of one or more rotors, of a UAV. For
example, the system 700 may be onboard a UAV as described herein.
The system 700 can include a controller 702 in electrical
communication with a sensor system 704, a memory 706 and an
actuation unit 708. The controller 702 can be configured to receive
information from the sensor system 704. For example, the sensor
system 704 may be configured to provide information as described
herein, such as information used by the controller 702 for
determining the change in configuration of one or more arms, and/or
the change in the angular velocity of one or more rotors. In some
embodiments, the sensor system 704 may comprise one or more sensors
configured to provide information relating to a configuration
state, orientation and/or position of one or more components of the
UAV, such as a payload, and/or an orientation and/or position of
the UAV. In some embodiments, the sensor system 704 may comprise a
gyroscope, inertial measurement unit (IMU), accelerometer, and mass
sensor, GPS sensor, combinations thereof, and/or the like. In some
embodiments, the controller 702 may retrieve one or more
predetermined values from the memory 706 for one or more
calculation processes. In some embodiments, one or more
predetermined values stored in the memory 706 may correspond to
values indicating the desired change in the one or more arms and/or
rotors. The memory 706 is shown as being distinct from the
controller 702. In some embodiments, the memory 706 may be a part
of the controller. The memory 706 can be removable from the system
700. One or more processors for performing various calculations
using the information from the sensor system 704 may be a part of
the controller 702. Based on calculations performed by the
controller 702 and/or values retrieved from the memory 706, the
controller 702 may generate one or more control signals for
communicating to the actuation unit 708. The actuation unit 708 may
be configured to receive the one or more control signals, and
effect the change to the angular velocity of one or more rotors of
the UAV and/or the change to the configuration of one or more arms
of the UAV based on the one or more control signals. For example,
the actuation unit 708 may be configured to effect a change in the
length of the one or arms.
[0095] In some embodiments, one or more processes for controlling
the operation of a UAV can include use of a feedback control loop.
In some embodiments, a feedback control loop can be used to adjust
the length of one or more arms of the UAV and/or the angular
velocity of one or more rotors of the UAV so as to adjust the
center of thrust of the UAV. FIG. 8 is a block diagram of an
example of a feedback control loop 800 for controlling a UAV. The
feedback control loop 800 may be used to adjust the length of one
or more arms and the angular velocity of one or more rotors of the
UAV to control the center of thrust of the UAV such that the UAV
may maintain a desired orientation in response to shifts in the
center of gravity of the UAV. For example, the feedback control
loop 800 can be used to adjust the angular velocity of one or more
rotors and/or the length of one or more arms based on measurements
from one or more sensors on the UAV configured to provide
information relating to the orientation of the UAV. Based on
orientation information of the UAV provided by one or more sensors
on the UAV, the feedback control loop 800 can determine adjustments
in the length of one or more arms and/or angular velocity of one or
more rotors to maintain the orientation of the UAV within desired
set-point values. For example, the feedback control loop 800 can be
configured to compare rotation of the UAV around one or more of the
x-, y-, and z-axes, or the roll, pitch, and yaw angles,
respectively, with corresponding roll angle, pitch angle, and yaw
angle set point values. Based on comparison of the roll angle,
pitch angle, and/or yaw angle with one or more corresponding
predetermined set point angle values, one or more processors of the
feedback control loop 800 can determine an output torque to be
applied to a rotor and/or force to be applied to a linear actuator
for extending or retracting an arm, so as to achieve the UAV
orientation and center of thrust. The feedback control loop can be
implemented using one or more of a proportional (P) controller, a
proportional-derivative (PD) controller, a proportional-integral
(PI) controller, a proportional-integral-derivative (PID)
controller, or combinations thereof.
[0096] The feedback loop 800 can include a processor 802 (e.g., a
digital signal processor (DSP)), a UAV orientation sensor 804, a
linear actuator 822, and a rotor 808. The processor 802 can be
located, for example on the central body of the UAV. The UAV
orientation sensor 804 can be any sensor suitable for obtaining
data indicative of the orientation of the UAV. In some embodiments,
the orientation sensor 804 can comprise one or more of an
accelerometer, a gyroscope, and/or an IMU. The UAV orientation
sensor 804 may be configured to provide information relating to the
rotation of the UAV around one or more of the x-, y-, and z-axes. A
plurality of sensors can be used, with each sensor providing
measurements along a different axis of motion.
[0097] The processor 802 can receive input angle set point value
810. The input angle set point value 810 can include a set point
angle value for the rotation of the UAV around one or more of the
x-, y- and z-axes. The processor 802 can also receive from the UAV
orientation sensor 804 a current angle value 812 indicating a
current or instantaneous angle at which the UAV is rotated around
one or more of the x-, y- and z-axes. The processor 802 can
calculate the difference between the input angle set point value
810 and the current angle value 812, also referred to as the
"error" in the rotational angle 814. The error in the rotational
angle 814 can be input into a PD controller 816. The PD controller
816 can be implemented according to methods known to those of skill
in the art. The PD controller 816 can output a rotor output 818
and/or a linear actuator output 820. The rotor output 818 can be
provided to a rotor 808 and the linear actuator output 820 can be
provided to a linear actuator 822. The rotor output 818 can be
configured such that a torque is generated at the rotor 808 to
rotate a set of corresponding rotor blades 824 at a desired angular
velocity. The linear actuator output 820 can be configured such
that the linear actuator 822 provides sufficient linear force upon
an arm 826 of the UAV to achieve desired extension or retraction of
the arm 826. The rotation of the rotor blades 824 and the extension
of the arm 826 are selected so as to provide the desired center of
thrust for the UAV, thereby achieve the desired UAV
orientation.
[0098] In some embodiments, an external disturbance to the rotor
808 and/or one or more components coupled to the rotor (e.g., a set
of rotor blades) may result in a disturbance torque 806 being
applied to the rotor 808, such that the actual amount of torque
applied to the rotor 808 may be the sum of the output torque
applied by the rotor 808 and the disturbance torque 806. Thus, it
can be seen that the additional disturbance torque 806 may cause
the angular velocity that is actually achieved by the rotor blades
824 to be different from the angular velocity that would otherwise
be achieved by applying the rotor output 818. These discrepancies
may be detrimental to accurate control of the UAV orientation. In
some embodiments, the feedback control loop 800 can include an
estimate for the disturbance torque 806 such that the torque
applied to the rotor 808 can be adjusted to account for the
disturbance torque 806.
[0099] FIG. 9 illustrates a movable object 900 including a carrier
902 and a payload 904, in accordance with embodiments. Although the
movable object 900 is depicted as an aircraft, this depiction is
not intended to be limiting, and any suitable type of movable
object can be used, as previously described herein. One of skill in
the art would appreciate that any of the embodiments described
herein in the context of aircraft systems can be applied to any
suitable movable object (e.g., a UAV), including a UAV as described
herein. In some instances, the payload 904 may be provided on the
movable object 900 without requiring the carrier 902. The movable
object 900 may include propulsion mechanisms 906, a sensing system
908, and a communication system 910.
[0100] The propulsion mechanisms 906 can include one or more of
rotors, propellers, blades, engines, motors, wheels, axles,
magnets, or nozzles, as previously described. For example, the
propulsion mechanisms 906 may be self-tightening rotors, rotor
assemblies, or other rotary propulsion units, as disclosed
elsewhere herein. The movable object may have one or more, two or
more, three or more, or four or more propulsion mechanisms. The
propulsion mechanisms may all be of the same type. Alternatively,
one or more propulsion mechanisms can be different types of
propulsion mechanisms. The propulsion mechanisms 906 can be mounted
on the movable object 900 using any suitable means, such as a
support element (e.g., a drive shaft) as described elsewhere
herein. The propulsion mechanisms 906 can be mounted on any
suitable portion of the movable object 900, such on the top,
bottom, front, back, sides, or suitable combinations thereof.
[0101] In some embodiments, the propulsion mechanisms 906 can
enable the movable object 900 to take off vertically from a surface
or land vertically on a surface without requiring any horizontal
movement of the movable object 900 (e.g., without traveling down a
runway). Optionally, the propulsion mechanisms 906 can be operable
to permit the movable object 900 to hover in the air at a specified
position and/or orientation. One or more of the propulsion
mechanism 900 may be controlled independently of the other
propulsion mechanisms. Alternatively, the propulsion mechanisms 900
can be configured to be controlled simultaneously. For example, the
movable object 900 can have multiple horizontally oriented rotors
that can provide lift and/or thrust to the movable object. The
multiple horizontally oriented rotors can be actuated to provide
vertical takeoff, vertical landing, and hovering capabilities to
the movable object 900. In some embodiments, one or more of the
horizontally oriented rotors may spin in a clockwise direction,
while one or more of the horizontally rotors may spin in a
counterclockwise direction. For example, the number of clockwise
rotors may be equal to the number of counterclockwise rotors. The
rotation rate of each of the horizontally oriented rotors can be
varied independently in order to control the lift and/or thrust
produced by each rotor, and thereby adjust the spatial disposition,
velocity, and/or acceleration of the movable object 900 (e.g., with
respect to up to three degrees of translation and up to three
degrees of rotation).
[0102] The sensing system 908 can include one or more sensors that
may sense the spatial disposition, velocity, and/or acceleration of
the movable object 900 (e.g., with respect to up to three degrees
of translation and up to three degrees of rotation). The one or
more sensors can include any of the sensors previously described
herein, including GPS sensors, motion sensors, inertial sensors,
proximity sensors, or image sensors. The sensing data provided by
the sensing system 908 can be used to control the spatial
disposition, velocity, and/or orientation of the movable object 900
(e.g., using a suitable processing unit and/or control module, as
described below). Alternatively, the sensing system 908 can be used
to provide data regarding the environment surrounding the movable
object, such as weather conditions, proximity to potential
obstacles, location of geographical features, location of manmade
structures, and the like.
[0103] The communication system 910 enables communication with
terminal 912 having a communication system 914 via wireless signals
916. The communication systems 910, 914 may include any number of
transmitters, receivers, and/or transceivers suitable for wireless
communication. The communication may be one-way communication, such
that data can be transmitted in only one direction. For example,
one-way communication may involve only the movable object 900
transmitting data to the terminal 912, or vice-versa. The data may
be transmitted from one or more transmitters of the communication
system 910 to one or more receivers of the communication system
912, or vice-versa. Alternatively, the communication may be two-way
communication, such that data can be transmitted in both directions
between the movable object 900 and the terminal 912. The two-way
communication can involve transmitting data from one or more
transmitters of the communication system 910 to one or more
receivers of the communication system 914, and vice-versa.
[0104] In some embodiments, the terminal 912 can provide control
data to one or more of the movable object 900, carrier 902, and
payload 904 and receive information from one or more of the movable
object 900, carrier 902, and payload 904 (e.g., position and/or
motion information of the movable object, carrier or payload; data
sensed by the payload such as image data captured by a payload
camera). In some instances, control data from the terminal may
include instructions for relative positions, movements, actuations,
or controls of the movable object, carrier and/or payload. For
example, the control data may result in a modification of the
location and/or orientation of the movable object (e.g., via
control of the propulsion mechanisms 906), or a movement of the
payload with respect to the movable object (e.g., via control of
the carrier 902). The control data from the terminal may result in
control of the payload, such as control of the operation of a
camera or other image capturing device (e.g., taking still or
moving pictures, zooming in or out, turning on or off, switching
imaging modes, change image resolution, changing focus, changing
depth of field, changing exposure time, changing viewing angle or
field of view). In some instances, the communications from the
movable object, carrier and/or payload may include information from
one or more sensors (e.g., of the sensing system 908 or of the
payload 904). The communications may include sensed information
from one or more different types of sensors (e.g., GPS sensors,
motion sensors, inertial sensor, proximity sensors, or image
sensors). Such information may pertain to the position (e.g.,
location, orientation), movement, or acceleration of the movable
object, carrier and/or payload. Such information from a payload may
include data captured by the payload or a sensed state of the
payload. The control data provided transmitted by the terminal 912
can be configured to control a state of one or more of the movable
object 900, carrier 902, or payload 904. Alternatively or in
combination, the carrier 902 and payload 904 can also each include
a communication module configured to communicate with terminal 912,
such that the terminal can communicate with and control each of the
movable object 900, carrier 902, and payload 904 independently.
[0105] In some embodiments, the movable object 900 can be
configured to communicate with another remote device in addition to
the terminal 912, or instead of the terminal 912. The terminal 912
may also be configured to communicate with another remote device as
well as the movable object 900. For example, the movable object 900
and/or terminal 912 may communicate with another movable object, or
a carrier or payload of another movable object. When desired, the
remote device may be a second terminal or other computing device
(e.g., computer, laptop, tablet, smartphone, or other mobile
device). The remote device can be configured to transmit data to
the movable object 900, receive data from the movable object 900,
transmit data to the terminal 912, and/or receive data from the
terminal 912. Optionally, the remote device can be connected to the
Internet or other telecommunications network, such that data
received from the movable object 900 and/or terminal 912 can be
uploaded to a website or server.
[0106] FIG. 10 is a schematic illustration by way of block diagram
of a system 1000 for controlling a movable object, in accordance
with embodiments. A movable object may include a UAV as described
herein. The system 1000 can be used in combination with any
suitable embodiment of the systems, devices, and methods disclosed
herein. The system 1000 can include a sensing module 1002,
processing unit 1004, non-transitory computer readable medium 1006,
control module 1008, and communication module 1010.
[0107] The sensing module 1002 can utilize different types of
sensors that collect information relating to the movable objects in
different ways. Different types of sensors may sense different
types of signals or signals from different sources. For example,
the sensors can include inertial sensors, GPS sensors, proximity
sensors (e.g., lidar), or vision/image sensors (e.g., a camera).
The sensing module 1002 can be operatively coupled to a processing
unit 1004 having a plurality of processors. In some embodiments,
the sensing module can be operatively coupled to a transmission
module 1012 (e.g., a Wi-Fi image transmission module) configured to
directly transmit sensing data to a suitable external device or
system. For example, the transmission module 1012 can be used to
transmit images captured by a camera of the sensing module 1002 to
a remote terminal.
[0108] The processing unit 1004 can have one or more processors,
such as a programmable processor (e.g., a central processing unit
(CPU)). The processing unit 1004 can be operatively coupled to a
non-transitory computer readable medium 1006. The non-transitory
computer readable medium 1006 can store logic, code, and/or program
instructions executable by the processing unit 1004 for performing
one or more steps. The non-transitory computer readable medium can
include one or more memory units (e.g., removable media or external
storage such as an SD card or random access memory (RAM)). In some
embodiments, data from the sensing module 1002 can be directly
conveyed to and stored within the memory units of the
non-transitory computer readable medium 1006. The memory units of
the non-transitory computer readable medium 1006 can store logic,
code and/or program instructions executable by the processing unit
1004 to perform any suitable embodiment of the methods described
herein. For example, the processing unit 1004 can be configured to
execute instructions causing one or more processors of the
processing unit 1004 to analyze sensing data produced by the
sensing module. The memory units can store sensing data from the
sensing module to be processed by the processing unit 1004. In some
embodiments, the memory units of the non-transitory computer
readable medium 1006 can be used to store the processing results
produced by the processing unit 1004.
[0109] In some embodiments, the processing unit 1004 can be
operatively coupled to a control module 1008 configured to control
a state of the movable object. For example, the control module 1008
can be configured to control the propulsion mechanisms of the
movable object to adjust the spatial disposition, velocity, and/or
acceleration of the movable object with respect to six degrees of
freedom. Alternatively or in combination, the control module 1008
can control one or more of a state of a carrier, payload, or
sensing module.
[0110] The processing unit 1004 can be operatively coupled to a
communication module 1010 configured to transmit and/or receive
data from one or more external devices (e.g., a terminal, display
device, or other remote controller). Any suitable means of
communication can be used, such as wired communication or wireless
communication. For example, the communication module 1010 can
utilize one or more of local area networks (LAN), wide area
networks (WAN), infrared, radio, WiFi, point-to-point (P2P)
networks, telecommunication networks, cloud communication, and the
like. Optionally, relay stations, such as towers, satellites, or
mobile stations, can be used. Wireless communications can be
proximity dependent or proximity independent. In some embodiments,
line-of-sight may or may not be required for communications. The
communication module 1010 can transmit and/or receive one or more
of sensing data from the sensing module 1002, processing results
produced by the processing unit 1004, predetermined control data,
user commands from a terminal or remote controller, and the
like.
[0111] The components of the system 1000 can be arranged in any
suitable configuration. For example, one or more of the components
of the system 1000 can be located on the movable object, carrier,
payload, terminal, sensing system, or an additional external device
in communication with one or more of the above. Additionally,
although FIG. 10 depicts a single processing unit 1004 and a single
non-transitory computer readable medium 1006, one of skill in the
art would appreciate that this is not intended to be limiting, and
that the system 1000 can include a plurality of processing units
and/or non-transitory computer readable media. In some embodiments,
one or more of the plurality of processing units and/or
non-transitory computer readable media can be situated at different
locations, such as on the movable object, carrier, payload,
terminal, sensing module, additional external device in
communication with one or more of the above, or suitable
combinations thereof, such that any suitable aspect of the
processing and/or memory functions performed by the system 1000 can
occur at one or more of the aforementioned locations.
[0112] The systems, devices, and methods described herein can be
applied to a wide variety of movable objects. As previously
mentioned, any description herein of an aerial vehicle may apply to
and be used for any movable object. A movable object of the present
disclosure can be configured to move within any suitable
environment, such as in air (e.g., a fixed-wing aircraft, a
rotary-wing aircraft, or an aircraft having neither fixed wings nor
rotary wings), in water (e.g., a ship or a submarine), on ground
(e.g., a motor vehicle, such as a car, truck, bus, van, motorcycle;
a movable structure or frame such as a stick, fishing pole; or a
train), under the ground (e.g., a subway), in space (e.g., a
spaceplane, a satellite, or a probe), or any combination of these
environments. The movable object can be a vehicle, such as a
vehicle described elsewhere herein. In some embodiments, the
movable object can be mounted on a living subject, such as a human
or an animal. Suitable animals can include avines, canines,
felines, equines, bovines, ovines, porcines, delphines, rodents, or
insects.
[0113] The movable object may be capable of moving freely within
the environment with respect to six degrees of freedom (e.g., three
degrees of freedom in translation and three degrees of freedom in
rotation). Alternatively, the movement of the movable object can be
constrained with respect to one or more degrees of freedom, such as
by a predetermined path, track, or orientation. The movement can be
actuated by any suitable actuation mechanism, such as an engine or
a motor. The actuation mechanism of the movable object can be
powered by any suitable energy source, such as electrical energy,
magnetic energy, solar energy, wind energy, gravitational energy,
chemical energy, nuclear energy, or any suitable combination
thereof. The movable object may be self-propelled via a propulsion
system, as described elsewhere herein. The propulsion system may
optionally run on an energy source, such as electrical energy,
magnetic energy, solar energy, wind energy, gravitational energy,
chemical energy, nuclear energy, or any suitable combination
thereof. Alternatively, the movable object may be carried by a
living being.
[0114] In some instances, the movable object can be a vehicle.
Suitable vehicles may include water vehicles, aerial vehicles,
space vehicles, or ground vehicles. For example, aerial vehicles
may be fixed-wing aircraft (e.g., airplane, gliders), rotary-wing
aircraft (e.g., helicopters, rotorcraft), aircraft having both
fixed wings and rotary wings, or aircraft having neither (e.g.,
blimps, hot air balloons). A vehicle can be self-propelled, such as
self-propelled through the air, on or in water, in space, or on or
under the ground. A self-propelled vehicle can utilize a propulsion
system, such as a propulsion system including one or more engines,
motors, wheels, axles, magnets, rotors, propellers, blades,
nozzles, or any suitable combination thereof. In some instances,
the propulsion system can be used to enable the movable object to
take off from a surface, land on a surface, maintain its current
position and/or orientation (e.g., hover), change orientation,
and/or change position.
[0115] The movable object can be controlled remotely by a user or
controlled locally by an occupant within or on the movable object.
In some embodiments, the movable object is an unmanned movable
object, such as a UAV. An unmanned movable object, such as a UAV,
may not have an occupant onboard the movable object. The movable
object can be controlled by a human or an autonomous control system
(e.g., a computer control system), or any suitable combination
thereof. The movable object can be an autonomous or semi-autonomous
robot, such as a robot configured with an artificial
intelligence.
[0116] The movable object can have any suitable size and/or
dimensions. In some embodiments, the movable object may be of a
size and/or dimensions to have a human occupant within or on the
vehicle. Alternatively, the movable object may be of size and/or
dimensions smaller than that capable of having a human occupant
within or on the vehicle. The movable object may be of a size
and/or dimensions suitable for being lifted or carried by a human.
Alternatively, the movable object may be larger than a size and/or
dimensions suitable for being lifted or carried by a human. In some
instances, the movable object may have a maximum dimension (e.g.,
length, width, height, diameter, diagonal) of less than or equal to
about: 2 cm, 5 cm, 10 cm, 50 cm, 1 m, 2 m, 5 m, or 10 m. The
maximum dimension may be greater than or equal to about: 2 cm, 5
cm, 10 cm, 50 cm, 1 m, 2 m, 5 m, or 10 m. For example, the distance
between shafts of opposite rotors of the movable object may be less
than or equal to about: 2 cm, 5 cm, 10 cm, 50 cm, 1 m, 2 m, 5 m, or
10 m. Alternatively, the distance between shafts of opposite rotors
may be greater than or equal to about: 2 cm, 5 cm, 10 cm, 50 cm, 1
m, 2 m, 5 m, or 10 m.
[0117] In some embodiments, the movable object may have a volume of
less than 100 cm.times.100 cm.times.100 cm, less than 50
cm.times.50 cm.times.30 cm, or less than 5 cm.times.5 cm.times.3
cm. The total volume of the movable object may be less than or
equal to about: 1 cm.sup.3, 2 cm.sup.3, 5 cm.sup.3, 10 cm.sup.3, 20
cm.sup.3, 30 cm.sup.3, 40 cm.sup.3, 50 cm.sup.3, 60 cm.sup.3, 70
cm.sup.3, 80 cm.sup.3, 90 cm.sup.3, 100 cm.sup.3, 150 cm.sup.3, 200
cm.sup.3, 300 cm.sup.3, 500 cm.sup.3, 750 cm.sup.3, 1000 cm.sup.3,
5000 cm.sup.3, 10,000 cm.sup.3, 100,000 cm.sup.3, 1 m.sup.3, or 10
m.sup.3. Conversely, the total volume of the movable object may be
greater than or equal to about: 1 cm.sup.3, 2 cm.sup.3, 5 cm.sup.3,
10 cm.sup.3, 20 cm.sup.3, 30 cm.sup.3, 40 cm.sup.3, 50 cm.sup.3, 60
cm.sup.3, 70 cm.sup.3, 80 cm.sup.3, 90 cm.sup.3, 100 cm.sup.3, 150
cm.sup.3, 200 cm.sup.3, 300 cm.sup.3, 500 cm.sup.3, 750 cm.sup.3,
1000 cm.sup.3, 5000 cm.sup.3, 10,000 cm.sup.3, 100,000 cm.sup.3, 1
m.sup.3, or 10 m.sup.3.
[0118] In some embodiments, the movable object may have a footprint
(which may refer to the lateral cross-sectional area encompassed by
the movable object) less than or equal to about: 32,000 cm.sup.2,
20,000 cm.sup.2, 10,000 cm.sup.2, 1,000 cm.sup.2, 500 cm.sup.2, 100
cm.sup.2, 50 cm.sup.2, 10 cm.sup.2, or 5 cm.sup.2. Conversely, the
footprint may be greater than or equal to about: 32,000 cm.sup.2,
20,000 cm.sup.2, 10,000 cm.sup.2, 1,000 cm.sup.2, 500 cm.sup.2, 100
cm.sup.2, 50 cm.sup.2, 10 cm.sup.2, or 5 cm.sup.2.
[0119] In some instances, the movable object may weigh no more than
1000 kg. The weight of the movable object may be less than or equal
to about: 1000 kg, 750 kg, 500 kg, 200 kg, 150 kg, 100 kg, 80 kg,
70 kg, 60 kg, 50 kg, 45 kg, 40 kg, 35 kg, 30 kg, 25 kg, 20 kg, 15
kg, 12 kg, 10 kg, 9 kg, 8 kg, 7 kg, 6 kg, 5 kg, 4 kg, 3 kg, 2 kg, 1
kg, 0.5 kg, 0.1 kg, 0.05 kg, or 0.01 kg. Conversely, the weight may
be greater than or equal to about: 1000 kg, 750 kg, 500 kg, 200 kg,
150 kg, 100 kg, 80 kg, 70 kg, 60 kg, 50 kg, 45 kg, 40 kg, 35 kg, 30
kg, 25 kg, 20 kg, 15 kg, 12 kg, 10 kg, 9 kg, 8 kg, 7 kg, 6 kg, 5
kg, 4 kg, 3 kg, 2 kg, 1 kg, 0.5 kg, 0.1 kg, 0.05 kg, or 0.01
kg.
[0120] In some embodiments, a movable object may be small relative
to a load carried by the movable object. The load may include a
payload and/or a carrier, as described in further detail below. In
some examples, a ratio of a movable object weight to a load weight
may be greater than, less than, or equal to about 1:1. In some
instances, a ratio of a movable object weight to a load weight may
be greater than, less than, or equal to about 1:1. Optionally, a
ratio of a carrier weight to a load weight may be greater than,
less than, or equal to about 1:1. When desired, the ratio of an
movable object weight to a load weight may be less than or equal
to: 1:2, 1:3, 1:4, 1:5, 1:10, or even less. Conversely, the ratio
of a movable object weight to a load weight can also be greater
than or equal to: 2:1, 3:1, 4:1, 5:1, 10:1, or even greater.
[0121] In some embodiments, the movable object may have low energy
consumption. For example, the movable object may use less than
about: 5 W/h, 4 W/h, 3 W/h, 2 W/h, 1 W/h, or less. In some
instances, a carrier of the movable object may have low energy
consumption. For example, the carrier may use less than about: 5
W/h, 4 W/h, 3 W/h, 2 W/h, 1 W/h, or less. Optionally, a payload of
the movable object may have low energy consumption, such as less
than about: 5 W/h, 4 W/h, 3 W/h, 2 W/h, 1 W/h, or less.
[0122] As used herein A and/or B encompasses one or more of A or B,
and combinations thereof such as A and B.
[0123] While some embodiments of the present disclosure have been
shown and described herein, it will be obvious to those skilled in
the art that such embodiments are provided by way of example only.
Numerous variations, changes, and substitutions will now occur to
those skilled in the art without departing from the disclosure. It
should be understood that various alternatives to the embodiments
of the disclosure described herein may be employed in practicing
the disclosure. It is intended that the following claims define the
scope of the invention and that methods and structures within the
scope of these claims and their equivalents be covered thereby.
* * * * *