U.S. patent application number 17/532453 was filed with the patent office on 2022-03-17 for laser radar scanning and positioning mechanisms for uavs and other objects, and associated systems and methods.
The applicant listed for this patent is SZ DJI TECHNOLOGY CO., LTD.. Invention is credited to WEI REN, JIEBIN XIE, ZHIPENG ZHAN.
Application Number | 20220083061 17/532453 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-17 |
United States Patent
Application |
20220083061 |
Kind Code |
A1 |
XIE; JIEBIN ; et
al. |
March 17, 2022 |
LASER RADAR SCANNING AND POSITIONING MECHANISMS FOR UAVS AND OTHER
OBJECTS, AND ASSOCIATED SYSTEMS AND METHODS
Abstract
Example embodiments include a motion mechanism that can be
coupled between the main body of an unmanned movable object and the
optoelectronic scanning module. The motion mechanism can include,
e.g., a spinning device and a tilting device. The spinning device
can be operable to rotate the scanning module relative to the main
body about a spin axis. The tilting device can be operable, e.g.,
in response to a tilt angle input, to rotate the scanning module
about an additional axis that is transverse to the spin axis.
Further example embodiments include an orientation sensor installed
on the main body of the unmanned movable object. Some embodiments
also provide a controller that is configured to receive an
orientation signal from the orientation sensor and, based at least
in part on the orientation signal, determine a tilt value for the
tilt angle input for the tilting device in the motion
mechanism.
Inventors: |
XIE; JIEBIN; (SHENZHEN,
CN) ; REN; WEI; (SHENZHEN, CN) ; ZHAN;
ZHIPENG; (SHENZHEN, CN) |
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Applicant: |
Name |
City |
State |
Country |
Type |
SZ DJI TECHNOLOGY CO., LTD. |
Sshenzhen |
|
CN |
|
|
Appl. No.: |
17/532453 |
Filed: |
November 22, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16283551 |
Feb 22, 2019 |
11188079 |
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17532453 |
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PCT/CN16/97540 |
Aug 31, 2016 |
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16283551 |
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International
Class: |
G05D 1/00 20060101
G05D001/00; B64C 39/02 20060101 B64C039/02; B64D 47/08 20060101
B64D047/08; G01S 17/89 20060101 G01S017/89; G01S 17/933 20060101
G01S017/933 |
Claims
1.-36. (canceled)
37. An unmanned movable object, comprising: a main body; an
orientation sensor carried by the main body; a scanning element
carried by the main body; a controller configured to receive an
orientation signal from the orientation sensor and, based at least
in part on the orientation signal, determine an input value; and a
motion mechanism coupled between the main body and the scanning
element, and operable to move the scanning element relative to the
main body according to the input value; wherein the controller is
configured to maneuver the unmanned movable object in response to
terrain or an obstacle detected by the scanning element.
38. The unmanned movable object of claim 37, wherein the motion
mechanism including a spinning device operable to rotate the
scanning element relative to the main body about a spin axis and a
tilting device operable to rotate the scanning element about an
additional axis that is transverse to the spin axis, and the motion
mechanism further includes an intermediate platform that the
spinning device is configured to rotate, and wherein the tilting
device is carried by the intermediate platform.
39. The unmanned movable object of claim 38, wherein the spinning
device is configured to rotate the scanning element via the
intermediate platform.
40. The unmanned movable object of claim 38, wherein the spinning
device carries the tilting device.
41. The unmanned movable object of claim 37, wherein the motion
mechanism including a spinning device operable to rotate the
scanning element relative to the main body about a spin axis and a
tilting device operable to rotate the scanning element about an
additional axis that is transverse to the spin axis, and the motion
mechanism further includes an intermediate platform that the
tilting device is configured to rotate, and wherein the spinning
device is carried by the intermediate platform.
42. The unmanned movable object of claim 37, wherein the motion
mechanism including a spinning device operable to rotate the
scanning element relative to the main body about a spin axis and a
tilting device operable to rotate the scanning element about an
additional axis that is transverse to the spin axis, and the
controller is configured to tilt the scanning element toward a
direction of travel of the unmanned movable object.
43. The unmanned movable object of claim 37, wherein the controller
is configured to compensate for a tilt angle of the main body when
the main body is not level.
44. The unmanned movable object of claim 37, wherein the controller
is configured to compensate for a tilt angle of the main body by
determining the input value to cause the scanning element to become
level.
45. The unmanned movable object of claim 37, wherein the controller
is configured to adjust a tilt angle of the scanning element by
determining the input value to cause the scanning element to become
level at least once per revolution of the scanning element when the
scanning element spins.
46. The unmanned movable object of claim 37, wherein the scanning
element includes a scanner and a scanning platform that carries the
scanner.
47. The unmanned movable object of claim 37, wherein the scanning
element includes a scanner, the scanner being configured to perform
terrestrial survey, obstruction detection, or a combination
thereof.
48. The unmanned movable object of claim 37, wherein the scanning
element comprises a light detection and ranging (LIDAR) system.
49. The unmanned movable object of claim 48, wherein the LIDAR
system includes a single-line laser emitter.
50. The unmanned movable object of claim 37, wherein the controller
is configured to: direct the unmanned movable object to become
level; rotate the scanning element to perform a first scan at a
first tilt angle; and rotate the scanning element to perform a
second scan at a second tilt angle.
51. The unmanned movable object of claim 37, wherein the scanning
element is weight balanced relative to a spin axis.
52. The unmanned movable object of claim 37, further comprising a
plurality of thrusters carried by the main body and positioned to
maneuver the unmanned movable object in response to inputs from the
controller.
53. The unmanned movable object of claim 52, wherein the controller
is configured to: tilt the scanning element toward a direction of
travel of the unmanned movable object; and maneuver the object in
response to terrain or an obstacle detected by a sensor carried by
the scanning element.
54. A non-transitory computer readable medium storing instructions
which, when executed, cause a controller to: receive an orientation
signal from an orientation sensor carried by a main body of an
unmanned movable object; determine an input value based at least in
part on the orientation signal; output the input value to a motion
mechanism carried by the unmanned movable object, wherein the
motion mechanism is operable to move a scanning element relative to
the main body according to the input value; and maneuver the
unmanned movable object in response to terrain or an obstacle
detected by the scanning element.
55. A method for operating an unmanned movable object, the method
comprising: directing the unmanned movable object to become level;
rotating a scanning element carried by the unmanned movable object
to perform a scan; and maneuvering the unmanned movable object in
response to terrain or an obstacle detected by the scanning
element.
56. The method of claim 55, further comprising: tilting the
scanning element toward a direction of travel of the unmanned
movable object.
Description
TECHNICAL FIELD
[0001] The present disclosure is directed generally to unmanned
movable apparatuses, and more specifically, to unmanned aerial
vehicles with optoelectronic scanning modules, and associated
components, systems and methods.
BACKGROUND
[0002] With their ever-increasing performance and lowering cost,
unmanned aerial vehicles (UAVs) are now extensively used in many
fields. Representative missions include crop surveillance, real
estate photography, inspection of buildings and other structures,
fire and safety missions, border patrols, and product delivery,
among others. To improve flight safety as well as the user's
experience (e.g., by making flight controls easier), it is
important for UAVs to be able to detect obstacles independently
and/or to automatically engage in evasive maneuvers. Laser radar
(LIDAR) is a reliable and stable detection technology because it is
able to function under nearly all weather conditions. However,
traditional LIDAR devices are typically expensive and heavy, making
most traditional LIDAR devices unfit for small and medium sized UAV
applications.
[0003] Accordingly, there remains a need for improved techniques
and systems for implementing LIDAR scanning functionality in UAVs
and other objects.
SUMMARY
[0004] The following summary is provided for the convenience of the
reader and identifies several representative embodiments of the
disclosed techniques. An unmanned aerial vehicle (UAV) apparatus in
accordance with a representative embodiment includes a main body,
an orientation sensor carried by the main body, a scanning element
carried by the main body, a controller, and a motion mechanism
coupled between the main body and the scanning element. The motion
mechanism includes a spinning device and a tilting device. The
spinning device can be operable to rotate the scanning element
relative to the main body about a spin axis. The tilting device can
be operable to rotate the scanning element about an additional axis
that is transverse to the spin axis in response to a tilt angle
input. The controller can be configured to receive an orientation
signal from the orientation sensor and, based at least in part on
the orientation signal, determine a tilt value for the tilt angle
input. In some examples, the spin axis is perpendicular to the
additional axis. The orientation sensor can be one or more of a
rotary encoder, or a Hall effect sensor.
[0005] In some embodiments, the motion mechanism includes an
intermediate platform that the spinning device is configured to
rotate. Some embodiments provide that the tilting device can be
carried by the intermediate platform. In certain implementations,
the spinning device can be configured to rotate the scanning
element via the intermediate platform. In one or more
configurations, the spinning device can carry the tilting
device.
[0006] In one or more embodiments, the controller is configured to
tilt the scanning element toward a direction of travel of the
object. In accordance with certain embodiments, the controller is
configured to compensate for a tilt angle of the main body when the
main body is not level. In some examples, the controller is
configured to compensate for a tilt angle of the main body by
directing the scanning element to become level. One or more
implementations provide that the controller is configured to adjust
a tilt angle of the scanning element by directing the scanning
element to become level at least once per revolution when the
scanning element spins.
[0007] The scanning element can be configured to spin continuously
at a generally constant rate. For example, the scanning element can
be configured to spin at approximately 10 to 20 revolutions per
second. In accordance with some embodiments, the tilting device
comprises a servo motor positioned to tilt the scanning element.
The scanning element can be weight balanced relative to the spin
axis.
[0008] The scanning element can include a scanner. In a number of
embodiments, the scanning element further includes a scanning
platform that carries the scanner. In many implementations, the
scanner is configured to perform a terrestrial survey, obstruction
detection, or a combination thereof. Certain embodiments of the
present technology also include the controller configured to
maneuver the object in response to the terrain or an obstacle
detected by the scanner. Some embodiments of the scanner can
include a light detection and ranging (LIDAR) system, and in some
examples, the LIDAR system can include a semiconductor laser diode
configured to emit light at a pulse rate of approximately 1000 Hz
or 3600 Hz. In accordance with many embodiments, the LIDAR system
includes a single-line laser emitter. In a number of examples, the
scanner includes a light emitting module and a light sensing
module. The light emitting module can include an infrared (IR)
light emitting diode (LED). The light sensing module can include a
photodiode.
[0009] The controller, according to some implementations, can be
configured to operate in a survey mode by performing a method that
includes directing the object to level, rotating the scanning
element to perform a first scan at a first tilt angle, and rotating
the scanning element to perform a second scan at a second tilt
angle.
[0010] In a variety of embodiments, a plurality of thrusters can be
carried by the main body and positioned to maneuver the object in
response to inputs from the controller. The controller can be
configured to, in a number of examples, tilt the scanning element
toward a direction of travel of the object, and maneuver the object
in response to the terrain or an obstacle detected by a sensor
carried by the scanning element. For example, the thrusters can
include airfoils, and in some cases, the thrusters can include four
propellers.
[0011] Embodiments of the present technology can also include a
radio frequency module, coupled to the controller, to receive
maneuvering commands from a remote controlling device.
[0012] Further embodiments include a method of controlling a system
that includes any and all combinations of the devices described
above, as well as a computer-readable medium that embodies computer
instructions that implement such a method. Still a further
embodiment includes manufacturing any and all combinations of the
devices described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1A is a schematic illustration of a representative
system having a moveable object with elements configured in
accordance with one or more embodiments of the present
technology.
[0014] FIG. 1B is a schematic illustration of the movable object of
FIG. 1A carrying a representative optoelectronic scanning module,
in accordance with an embodiment of the present technology.
[0015] FIG. 2 is an enlarged view of a laser radar (LIDAR) light
emitting module having multiple laser beam emitters used to scan
vertically to cover potential obstacles at different altitudes.
[0016] FIGS. 3A-3B illustrate an example deficiency observed in an
embodiment implementing a single-line laser using a single-axis
rotation mechanism in operation.
[0017] FIG. 4 is a schematic illustration of an approach that
employs a dual-axis motion mechanism to perform both horizontal and
vertical scans, in accordance with an embodiment of the present
technology.
[0018] FIG. 5 illustrates an embodiment implementing a dual-axis
motion mechanism operating in accordance with embodiments of the
present technology.
[0019] FIGS. 6A-6C illustrate devices in accordance with several
embodiments of the present technology.
[0020] FIG. 7 illustrates an additional function that embodiments
of the present technology can be configured to perform.
DETAILED DESCRIPTION
[0021] It is important for unmanned aerial vehicles (UAVs) to be
able to independently detect obstacles and/or to automatically
engage in evasive maneuvers. Light detection and ranging (LIDAR) is
a reliable and stable detection technology because LIDAR can remain
functional under nearly all weather conditions. However,
traditional LIDAR devices are typically expensive and heavy, making
most traditional LIDAR devices unsuitable for many UAV
applications.
[0022] Accordingly, the present technology is directed to
techniques for implementing a motion mechanism for carrying and
operating an optoelectronic scanning module (e.g., a LIDAR module).
The present technology enables the use of a single-line laser LIDAR
module for three-dimensional scanning, thus lowering the cost to
implement LIDAR on smaller or cheaper UAVs, while still producing
advantages (e.g., high precision, and all-weather operation) the
same as or similar to those associated with more expensive
multi-line LIDAR variants. Example embodiments of the various
techniques described herein include a motion mechanism that can be
coupled between the main body of an unmanned movable object and the
optoelectronic scanning module. The motion mechanism can include,
e.g., a spinning device and a tilting device. The spinning device
can be operable to rotate the scanning module relative to the main
body about a spin axis. The tilting device can be operable, e.g.,
in response to a tilt angle input, to rotate the scanning module
about an additional axis that is transverse to the spin axis.
Further example embodiments include an orientation sensor installed
on the main body of the unmanned movable object. Some embodiments
also provide a controller that is configured to receive an
orientation signal from the orientation sensor and, based at least
in part on the orientation signal, determine a tilt value for the
tilt angle input for the tilting device of the motion
mechanism.
[0023] In the following description, the example of a UAV is used,
for illustrative purposes only, to explain various techniques that
can be implemented using a motion mechanism to carry a simpler
LIDAR scanning module (e.g., a single-line LIDAR), to reduce or
eliminate the need of traditional LIDAR implementations (e.g.,
multi-line LIDARs). In other embodiments, the techniques described
here are applicable to other suitable scanning modules, vehicles,
or both. For example, even though one or more figures described in
connection with the techniques illustrate a UAV, in other
embodiments, the techniques are applicable in a similar manner to
other type of movable objects including, but not limited to, an
unmanned land or water vehicle, a hand-held device, or a robot. In
another example, even though the techniques are particularly
applicable to laser beams produced by laser diodes in a LIDAR
system, other types of light sources (e.g., other types of lasers,
or light emitting diodes (LEDs)) can be applicable in other
embodiments.
[0024] In the following description, numerous specific details are
set forth to provide a thorough understanding of the presently
disclosed technology. In other embodiments, the techniques
described here can be practiced without these specific details. In
other instances, well-known features, such as specific fabrication
techniques, are not described in detail in order to avoid
unnecessarily obscuring the present technology. References in this
description to "an embodiment," "one embodiment," or the like, mean
that a particular feature, structure, material, or characteristic
being described is included in at least one embodiment of the
present disclosure. Thus, the appearances of such phrases in this
specification do not necessarily all refer to the same embodiment.
On the other hand, such references are not necessarily mutually
exclusive either. Furthermore, the particular features, structures,
materials, or characteristics can be combined in any suitable
manner in one or more embodiments. Also, it is to be understood
that the various embodiments shown in the Figures are merely
illustrative representations and are not necessarily drawn to
scale.
[0025] Several details describing structures or processes that are
well-known and often associated with UAVs and corresponding systems
and subsystems, but that can unnecessarily obscure some significant
aspects of the disclosed techniques, are not set forth in the
following description for purposes of clarity. Moreover, although
the following disclosure sets forth several embodiments of
different aspects of the present disclosure, several other
embodiments can have different configurations or different
components than those described in this section. Accordingly, the
described techniques can have other embodiments with additional
elements or without several of the elements described below.
[0026] Many embodiments of the present disclosure described below
can take the form of computer- or controller-executable
instructions, including routines executed by a programmable
computer or controller. Those skilled in the relevant art will
appreciate that the described techniques can be practiced on
computer or controller systems other than those shown and described
below. The techniques described herein can be embodied in a
special-purpose computer or data processor that is specifically
programmed, configured or constructed to perform one or more of the
computer-executable instructions described below. Accordingly, the
terms "computer" and "controller" as generally used herein refer to
any data processor and can include Internet appliances and handheld
devices (including palm-top computers, wearable computers, cellular
or mobile phones, multi-processor systems, processor-based or
programmable consumer electronics, network computers, mini
computers and the like). Information handled by these computers and
controllers can be presented at any suitable display medium,
including a liquid crystal display (LCD). Instructions for
performing computer- or controller-executable tasks can be stored
in or on any suitable computer-readable medium, including hardware,
firmware or a combination of hardware and firmware. Instructions
can be contained in any suitable memory device, including, for
example, a flash drive, USB device, and/or other suitable
medium.
[0027] The terms "coupled" and "connected," along with their
derivatives, can be used herein to describe structural
relationships between components. It should be understood that
these terms are not intended as synonyms for each other. Rather, in
particular embodiments, "connected" can be used to indicate that
two or more elements are in direct contact with each other. Unless
otherwise made apparent in the context, the term "coupled" can be
used to indicate that two or more elements are in either direct or
indirect (with other intervening elements between them) contact
with each other, or that the two or more elements co-operate or
interact with each other (e.g., as in a cause and effect
relationship), or both.
1. Overview
[0028] FIG. 1A is a schematic illustration of a representative
system 100 having elements in accordance with one or more
embodiments of the present technology. The system 100 includes a
movable object 110 and a control system 140. Although the movable
object 110 is depicted as an unmanned aerial vehicle (UAV), this
depiction is not intended to be limiting, and any suitable type of
movable object can be used in other embodiments, as described
herein.
[0029] The moveable object 110 can include a main body 111 (e.g.,
an airframe) that can carry a payload 120, for example, an imaging
device or an optoelectronic scanning device (e.g., a LIDAR device).
In particular embodiments, the payload 120 can be a camera, for
example, a video camera and/or still camera. The camera can be
sensitive to wavelengths in any of a variety of suitable bands,
including visual, ultraviolet, infrared and/or other bands. In
still further embodiments, the payload 120 can include other types
of sensors and/or other types of cargo (e.g., packages or other
deliverables). In many of these embodiments, the payload 120 is
supported relative to the main body 111 with a carrying mechanism
125. The carrying mechanism 125, in some embodiments, can allow the
payload 120 to be independently positioned relative to the main
body 111. For instance, the carrying mechanism 125 can permit the
payload 120 to rotate around one, two, three, or more axes. In
other embodiments, the carrying mechanism 125 can permit the
payload 120 to move linearly along one, two, three, or more axes.
The axes for the rotational or translational movement may or may
not be orthogonal to each other depending upon the particular
embodiment. In this way, when the payload 120 includes an imaging
device, the imaging device can be moved relative to the main body
111, e.g., to photograph, video or track a target.
[0030] In some embodiments, the payload 120 can be rigidly coupled
to or connected with the movable object 110 such that the payload
120 remains generally stationary relative to the movable object
110. For example, the carrying mechanism 125 that connects the
movable object 110 and the payload 120 may not permit the payload
120 to move relative to the movable object 110. In other
embodiments, the payload 120 can be coupled directly to the movable
object 110 without requiring the carrying mechanism 125. In some
examples, the carrying mechanism can include a mechanical
mechanism, such as a pan head or a ball head, that allows for
adjustments in one or more axes. A pan head, also known as a
pan-and-tilt head, may allow independent rotation of the payload
about two or three perpendicular axes. A ball head may include a
ball and socket type joint for orientation control; for example,
the ball can sit in a socket, which can be tightened to lock the
ball in place. Some implementations of the carrying mechanism can
provide the ability to restrict movement to a single axis.
Additionally, some carrying mechanisms may include
electromechanical components to provide automated or assisted
target tracking functionality.
[0031] One or more propulsion units 130 can enable the movable
object 110 to move, e.g., to take off, land, hover, and move in the
air with respect to up to three degrees of freedom of translation
and up to three degrees of freedom of rotation. In some
embodiments, the propulsion units 130 can include one or more
rotors. The rotors can include one or more rotor blades coupled to
a shaft. The rotor blades and shaft can be rotated by a suitable
drive mechanism, such as a motor. Although the propulsion units 130
of the moveable object 110 are depicted as propeller-based and can
have four rotors (as shown in FIG. 1B), any suitable number, type,
and/or arrangement of propulsion units can be used depending upon
the particular embodiment. For example, the number of rotors can be
one, two, three, four, five, or even more. The rotors can be
oriented vertically, horizontally, or at any other suitable angle
with respect to the moveable object 110. The pitch angle of the
rotors can be fixed or variable. The propulsion units 130 can be
driven by any suitable motor, such as a DC motor (e.g., brushed or
brushless) or an AC motor. In some embodiments, the motor can be
configured to mount and drive a rotor blade.
[0032] The movable object 110 is configured to receive control
commands from the control system 140. In an embodiment shown in
FIG. 1A, the control system 140 includes some components carried on
the moveable object 110 and some components positioned off the
moveable object 110. For example, the control system 140 can
include a first controller 142 carried by the moveable object 110
and a second controller 144 (e.g., a human-operated, remote
controller) positioned remote from the moveable object 110 and
connected via a communication link 146 (e.g., a wireless link such
as a radio frequency (RF) based link). The first controller 142 can
include a computer-readable medium 143 that executes instructions
directing the actions of the moveable object 110, including, but
not limited to, operation of the propulsion system 130 and the
payload 120 (e.g., a camera). The second controller 144 can include
one or more input/output devices, e.g., display and control
buttons. The operator manipulates the second controller 144 to
control the moveable object 110 remotely, and receives feedback
from the moveable object 110 via the display and/or other
interfaces of the second controller 144. In other representative
embodiments, the moveable object 110 can operate autonomously, in
which case the second controller 144 can be eliminated, or can be
used solely for operator override functions.
[0033] FIG. 1B schematically illustrates the moveable object 110 of
FIG. 1A carrying a representative optoelectronic scanning module
(or scanning element) 150. The scanning module 150 can be carried
by a motion mechanism 126. The motion mechanism 126 can be the same
as or similar to the carrying mechanism 125 for the payload 120,
described above with reference to FIG. 1A. For example, as
illustrated in FIG. 1B, the motion mechanism 126 includes a
spinning device 127 (e.g., an electric motor) and a support rod
129. The motion mechanism 126 is coupled between the main body of
the moveable object 110 and the scanning module 150 so as to
connect the two together. Further, in a number of embodiments, the
motion mechanism 126 is operable (e.g., either by control from the
second controller 144 (FIG. 1A) or autonomously by programming) to
rotate the scanning module 150 relative to the main body about a
spin axis 102. Accordingly, the scanning module 150 can perform
horizontal scans (e.g., 360 degree horizontal scans).
[0034] The optoelectronic scanning module 150 can include a
scanning platform 152 carrying a light emitting module 154 and a
light sensing module 156. The light emitting module 154 is
positioned to emit light, and the light sensing module 156 is
positioned to detect a reflected portion of the emitted light. In
many implementations, the optoelectronic scanning module 150 is a
LIDAR module, and the light emitting module 154 includes a
semiconductor laser diode (e.g., a P-I-N structured diode). The
light sensing module 156 can include photodetectors, e.g., solid
state photodetectors (including silicon (Si)), avalanche
photodiodes (APD), photomultipliers, or combinations of the
foregoing. In some implementations, the semiconductor laser diode
can emit a laser light at a pulse rate of approximately 1000 Hz or
3600 Hz.
[0035] In various embodiments, the scanning module 150 can perform
a three-dimensional (3D) scanning operation, covering both
horizontal and vertical directions, in order to detect obstacles
and/or to conduct terrestrial surveys. Objects that can be detected
typically include any physical objects or structures, including
geographical landscapes (e.g., mountains, trees, or cliffs),
buildings, vehicles (e.g., aircraft, ships, or cars), or indoor
obstacles (e.g., walls, tables, or cubicles). Other objects include
live subjects such as people or animals. The objects can be moving
or stationary.
[0036] FIG. 2 shows an enlarged view of a laser radar (LIDAR) light
emitting module 254 having multiple laser beam emitters 254a-254d
used to scan vertically to cover potential obstacles at different
altitudes. As discussed above, a 3D laser radar typically scans in
two planes, e.g., horizontal and vertical. In the horizontal plane,
an electric motor (e.g., a spinning device 127, shown in FIG. 1B)
can be used to drive the laser beams emitted by a light emitting
module 254 to rotate and scan in a 360-degree range.
[0037] In the vertical plane, in order to cover potential obstacles
at different altitudes, one approach (as shown in FIG. 2) is to use
multiple laser beams, with each laser beam configured to cover
obstacles at a different altitude. This approach requires multiple
laser emitters (e.g., emitters 254a-254d) to operate
simultaneously, which increases cost, power consumption, and weight
of the unit. Moreover, in many applications (e.g., those where one
of the primary objectives for utilizing LIDAR is collision
avoidance from stationary objects during flight), using multiple
laser emitters in the LIDAR may be not only costly but also
wasteful. Often times, in these applications, a single laser
emitter is sufficient for purposes of the specific application
(e.g., for performing obstacle detection and avoidance during
flight) because only obstacles ahead in a single direction (e.g.,
the flight direction) are of interest. However, using a single-line
LIDAR module may also have drawbacks.
[0038] FIGS. 3A-3B illustrate an example deficiency observed in an
embodiment implementing a single-line laser using a single-axis
rotation mechanism in operation. As shown in FIGS. 3A-3B, to detect
an obstacle 360 in front of a UAV 310, a single-line LIDAR module
with a single laser emitter 354 (that emits a single-line laser
signal 355) is installed on a single-axis rotation mechanism 326
via a scanning platform 352.
[0039] Specifically, in the example shown in FIG. 3A, the laser
emitter 354 emits the laser signal 355 at a frequency (e.g., 1000
Hz or 3600 Hz), under the control of a program executed by a main
control unit (e.g., the controller 142, shown in FIG. 1A). When the
signal 355 encounters the obstacle 360, the signal 355 is reflected
by the obstacle 360, and the reflected signal is detected by a
light sensor 356 in the LIDAR module. Via a spinning device 327
(e.g., an electric motor), the single-line LIDAR can perform
scanning (e.g., a 360-degree scan) in the horizontal plane. The
scanning frequency (e.g., expressed as revolutions per second) can
be controlled by the rotating electric motor, either manually
through a remote controller (e.g., controller 144, FIG. 1A) or a
computer program stored in the storage medium (e.g., medium 143,
FIG. 1A) coupled to the controller onboard the UAV 310. In this
way, the main controller or another module can calculate the
distance from the UAV 310 to the obstacle 360 based on a time
difference between the emittance of the laser light 355 and the
detection of the reflected laser light. This process accordingly
implements a single-direction obstacle detection and range
estimation function. Note that, because the LIDAR module is
connected to the UAV 310 through a single-axis rotation mechanism
326 (e.g., via a bracket), the scanning platform 352 that carries
the LIDAR module is generally parallel to the main body 311 of the
UAV 310, such that the scanning plane of the single-line LIDAR can
be parallel to the main body 311.
[0040] However, as shown in FIG. 3B, during flight of the UAV 310,
the vehicle's pitch angle or attitude 370 can change with the
flight speed and acceleration in a given direction. For example,
typically when the UAV 310 flies at a low and constant speed, the
vehicle's attitude 370 can be roughly parallel to the ground;
however, when the same vehicle flies at a higher speed or
accelerates, the vehicle's attitude 370 may decrease so that the
vehicle is tilted down (e.g., by about 30 degrees). If there is an
obstacle 360 in the motion direction 375 of the UAV 310 during an
acceleration and the scanning direction (as represented by the
single-line laser signal 355) of the LIDAR deviates significantly
from the motion direction 375, then the single-line LIDAR may be
unable to detect the obstacle 360.
2. Representative Embodiments
[0041] Techniques described below implement a multi-axis (e.g.,
dual-axis) motion mechanism that, in addition to the spinning
device described above (e.g., the spinning device 127, shown in
FIG. 1B), includes at least a tilting device to provide an
additional degree of freedom. The tilting device can be configured
to adjust the scanning direction such that the single-line laser
can consistently aim in the direction of travel (e.g., at least
once per revolution), regardless of the attitude of the main body
of the vehicle. The adjustment can be performed based on, for
example, an orientation sensor (e.g., an inertial measurement unit
(IMU)) carried by the main body of the vehicle. The IMU can
include, for example, a gyroscope, an accelerometer, a rotary
encoder, a Hall effect sensor, or any suitable combination thereof.
In some embodiments, through the multi-axis motion mechanism, the
single-line laser can be instructed to aim at other directions as
well, e.g., for purposes of range estimation of a certain object or
for conducting 3D scanning of the local terrain. Because this
approach enables implementing LIDAR obstacle detection using as few
as one pair of laser emitting and sensing devices, the cost and
complexity of the LIDAR module on the UAV can be greatly reduced,
making a single-line LIDAR module more suitable than the
traditional multi-line LIDAR scanners for cost-sensitive, small to
medium sized unmanned aerial vehicle applications.
[0042] FIG. 4 is a schematic illustration of an approach that
employs a multi-motor (e.g., dual-motor) mechanism 426 on a UAV 410
to perform both horizontal and vertical scans, in accordance with
an embodiment of the present technology. FIG. 5 illustrates an
embodiment implementing a single-line laser using a dual-motor
mechanism in operation. With simultaneous reference to FIGS. 4 and
5, embodiments of the present technology are further described
below.
[0043] Specifically, the dual-motor motion mechanism 426 can
include a spinning motor 427 and a tilting motor 428 to perform
both horizontal and vertical scans. This approach can achieve 3D
scanning using a single-line laser (e.g., from a single laser
diode). The UAV 410 carries a single-line LIDAR module 450.
Included in the LIDAR module 450 is a laser emitter 454, which can
contain a laser diode and one or more lenses for collimating or
other purposes. In a manner that same as or similar to the
single-line LIDAR modules described above, the LIDAR module 450 can
be controlled by a main control unit (e.g., controller 142, shown
in FIG. 1A) on the UAV 410 to emit a pulse laser signal. The LIDAR
module 450 further includes a light sensor 456, which can include,
e.g., a focusing lens, a photodiode, and an analog-to-digital
converter (ADC). The ADC can convert a detected optical signal into
an electrical signal and output the electrical signal to the main
control unit, which can in turn perform, for example, obstacle
detection, terrain survey, or collision avoidance. Elements of the
LIDAR module 450 including, for example, the light emitter 454 and
the light sensor 456, are installed on or otherwise carried by a
scanning platform 453.
[0044] As shown in FIG. 4, a single-line LIDAR module 450 with a
single laser emitter 454 is installed on a multi-axis motion
mechanism 426 via the scanning platform 453. The motion mechanism
426 includes at least two servo motors (e.g., electric motors),
e.g., a spinning motor 427 and a tilting motor 428. The spinning
motor 427 and the tilting motor 428 can be used to control the
scanning operation of the LIDAR module 450 in the horizontal plane
and the vertical plane, respectively. Similar to the motion
mechanism 126 described above with respect to FIG. 1B, the spinning
motor 427 is operable to rotate the scanning LIDAR module 450
relative to the main body 411 of the UAV 410 about a spin axis 402.
In some embodiments, the spinning motor 427 can spin the LIDAR
module 450 at a generally constant rate (e.g., .+-.10%). In certain
examples, the rate is approximately 10 to 20 revolutions per second
(r.p.s.). Depending on the implementation, the spinning can be
either controlled by the main controller onboard the UAV 410 or by
another suitable circuit. In other embodiments, the spinning motor
427 can be a simple constant speed motor. In particular embodiments
(e.g., where the scanning module 450 is constantly spinning), the
scanning module 450 together with the motion mechanism 426 can be
weight balanced relative to the spin axis 402.
[0045] The tilting motor 428 can be operable to rotate the scanning
LIDAR module 450 about an additional axis 404 that is transverse to
the spin axis 402, in response to a tilt angle input. In some
examples, the additional axis 404 is perpendicular to the spin axis
402. Further, an orientation sensor 412 can be carried by the main
body 411. Examples of the orientation sensor 412 can include an
IMU, which may include a gyroscope, an accelerometer, a rotary
encoder, a Hall effect sensor, or any combination of sensors
suitable for detecting the pitch angle of the main body 411 in a
timely and accurate manner. According to a number of embodiments of
the present technology, a controller on the UAV 410 (e.g., the main
controller 142, shown in FIG. 1A) can be configured to receive an
orientation signal from the orientation sensor 412 and, based at
least in part on the orientation signal, determine a tilt value for
the tilt angle input of the tilting motor 428. Through the
orientation sensor 412 installed on the UAV 410, a current attitude
(or pitch angle) 570 of the vehicle 410 can be obtained. The
controller can be configured to compensate for the pitch angle 570
of the main body 411 when the main body 411 is not level, for
example, by directing the tilting motor 428 to cause the scanning
platform 453 to become level. Therefore, during operation of the
UAV 410, the controller can obtain the pitch angle 570 and use that
information to control the tilting motor 428 to compensate for the
pitch angle. Accordingly, the direction of the LIDAR laser beam
emitted by the LIDAR module 450 can be consistently aligned with
the direction of the flight of the vehicle 410, so as to detect the
obstacle 360. In this way, the motion mechanism 426 and the
scanning LIDAR module 450 are able to detect obstacles even when
the main body 411 is tilted.
[0046] Note that, during operation, the motion mechanism 426 may
cause the scan plane of single-line LIDAR module 450 to change, and
more specifically, to become conical rather than flat. However,
this result generally does not adversely affect the obstacle
detection and collision avoidance processes, because the scanning
platform 452c becomes level at least once each time the scanning
LIDAR module 450 rotates 360 degrees. In other words, as long as
the tilt angle is adjusted by the controller such that the scanning
LIDAR module 450 is level (or otherwise aligned with the vehicle
direction of motion) at least once per revolution as the scanning
module 450 spins, it is generally sufficient for the module 450 to
detect the obstacle 360 in the direction of flight.
[0047] FIGS. 6A-6C illustrate several systems in accordance with
embodiments of the present technology. As shown in FIG. 6A, the
system can include a motion mechanism 626a having a dual-axis
configuration that includes an intermediate platform 652a that is
rotated by a spinning device 627a. A tilting device 628a is carried
by the intermediate platform 652a to tilt a scanning platform 653a.
That is to say, the spinning device 627a is configured to rotate
the scanning element (e.g., the LIDAR module 450) via the
intermediate platform 652a, with the spinning device 627a carrying
the tilting device 628a.
[0048] FIG. 6B illustrates another embodiment that includes a
motion mechanism 626b having a dual-axis configuration. A
corresponding intermediate platform 652b is simplified to have the
shape/configuration of a rod. The intermediate platform 652b is
rotated by a corresponding spinning device 627b. A corresponding
tilting device 628b is carried by the intermediate platform 652b
and is positioned to tilt a corresponding scanning platform
653b.
[0049] FIG. 6C illustrates a corresponding motion mechanism 626c
configured in accordance with another embodiment of the present
technology. The motion mechanism 626c is also a dual-axis motion
mechanism; however, in this embodiment, it is a tilting device 628c
that carries a corresponding spinning device 627c. Specifically,
the tilting device 628c can tilt an intermediate platform 653c,
which in turn carries the spinning device 627c. The spinning device
627c, carried by the intermediate platform 653c, rotates a
corresponding scanning platform 652c. That is to say, the tilting
device 627c is configured to tilt the scanning element (e.g., the
LIDAR module 450) via the intermediate platform 653c.
[0050] FIG. 7 illustrates an additional function that embodiments
of the present technology can perform. In particular, with the
multi-axis motion mechanism described herein, embodiments of the
present technology can enable 3D scanning using a single-line
LIDAR. Specifically, when the vehicle 410 is stationary (e.g.,
hovering in flight or positioned on the ground), the optoelectronic
scanning platform can be tilted (e.g., by the tilting motor 428) to
aim at any angle, thereby achieving 3D scanning of the terrain 765
and obstacle range detection for various altitudes that are within
the range of the tilting device.
[0051] For example, after directing the UAV 410 to level, the
controller onboard the UAV 410 can first cause the spinning device
427 of the motion mechanism 426 to rotate the single-line LIDAR for
360 degrees while the tilting device 428 is at a first tilt angle,
thereby performing a first scan 755a. Afterwards, the controller
onboard the UAV 410 can cause the spinning device 427 to rotate the
single-line scanning element (e.g., scanning module 450) 360
degrees with the tilting device 428 at different tilt angle,
thereby performing subsequent scans (e.g., scans 755b and 755c) at
different altitudes. In this way, a 3D depth drawing (such as is
shown by the contours of the terrain 765 in FIG. 7) can be plotted,
by gradually changing the vertical scanning direction. With the
motion mechanism described herein, a single-line LIDAR scanner can
be configured to perform terrestrial survey, obstruction detection,
or more.
[0052] In some embodiments, the detected terrain information can be
used in combination with other data such as other vehicle
orientation information produced by sensors onboard the UAV, and
the controller can maneuver the UAV in response to the terrain or
obstacle detected by the scanner, thereby achieving independent
positioning and autonomous flying.
3. Conclusion
[0053] From the foregoing, it will be appreciated that specific
embodiments of the technology have been described herein for
purposes of illustration, but that various modifications can be
made without deviating from the technology. In representative
embodiments, the LIDAR devices can have configurations other than
those specifically shown and described herein, including other
semiconductor constructions. The optical devices described herein
may have other configurations in other embodiments, which also
produce the desired beam shapes and characteristics described
herein. While representative embodiments were described above in
the content of small to medium sized UAVs, aspects of the
technology described herein can be applied to other UAVs and/or
other vehicles in other embodiments.
[0054] Certain aspects of the technology described in the context
of particular embodiments may be combined or eliminated in other
embodiments. For example, aspects of the optical structure
described in the context of FIGS. 6 and 7 may be applied to
embodiments other than those specifically shown in the Figures.
Further, while advantages associated with certain embodiments of
the technology have been described in the context of those
embodiments, other embodiments may also exhibit such advantages,
and not all embodiments need necessarily exhibit such advantages to
fall with within the scope of the present technology. Accordingly,
the present disclosure and associated technology can encompass
other embodiments not expressly shown or described herein.
[0055] To the extent any materials incorporated herein by reference
conflict with the present disclosure, the present disclosure
controls.
[0056] At least a portion of the disclosure of this patent document
contains material which is subject to copyright protection. The
copyright owner has no objection to the facsimile reproduction by
anyone of the patent document or the patent disclosure, as it
appears in the Patent and Trademark Office patent file or records,
but otherwise reserves all copyright rights whatsoever.
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