U.S. patent application number 11/534838 was filed with the patent office on 2007-01-25 for compact robotic joint.
This patent application is currently assigned to DISNEY ENTERPRISES, INC.. Invention is credited to Akhil Jiten Madhani, Bryan S. Tye.
Application Number | 20070021031 11/534838 |
Document ID | / |
Family ID | 34740094 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070021031 |
Kind Code |
A1 |
Madhani; Akhil Jiten ; et
al. |
January 25, 2007 |
Compact Robotic Joint
Abstract
In one aspect, a supported walking system is disclosed,
comprising a robotic walking figure and a wheeled support that at
least partially supports the robotic walking figure. The supported
walking system may be driven and controlled by a human operator.
Computer algorithms automatically control the robot's walking
functions so that it may step forwards, backwards, and sideways in
synchronicity with the movements of the cart while driving and
turning at varying speeds.
Inventors: |
Madhani; Akhil Jiten;
(Burbank, CA) ; Tye; Bryan S.; (Burbank,
CA) |
Correspondence
Address: |
DISNEY ENTERPRISES, INC.;C/O HOGAN & HARTSON LLP
1200 SEVENTEENTH STREET
ONE TABOR CENTER, SUITE 1500
DENVER
CO
80202
US
|
Assignee: |
DISNEY ENTERPRISES, INC.
500 S. Buena Vista Street
Burbank
CA
|
Family ID: |
34740094 |
Appl. No.: |
11/534838 |
Filed: |
September 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10757797 |
Jan 14, 2004 |
|
|
|
11534838 |
Sep 25, 2006 |
|
|
|
60440291 |
Jan 14, 2003 |
|
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Current U.S.
Class: |
446/377 |
Current CPC
Class: |
A63H 11/00 20130101;
B62D 57/032 20130101; B62D 57/028 20130101 |
Class at
Publication: |
446/377 |
International
Class: |
A63H 7/00 20060101
A63H007/00 |
Claims
1. A compact robotic joint having two rotational degrees of
freedom, comprising: a first link; a second link, wherein the first
link is rotatably mounted to the second link and movable relative
to the second link about a first axis; and a third link rotatably
mounted to the second link and movable relative to the second link
about a second axis; wherein the first link and the third link each
comprises a rotary actuator.
2. The compact robotic joint of claim 1, wherein the rotary
actuator comprises an electric motor.
3. The compact robotic joint of claim 2, wherein the rotary
actuator further comprises a gearbox.
4. The compact robotic joint of claim 1, wherein the rotary
actuator is a hydraulic actuator.
5. The compact robotic joint of claim 1, wherein the first axis is
substantially perpendicular to the second axis.
6. The compact robotic joint of claim 5, wherein the first axis
intersects or nearly intersects the second axis in the second
link.
7. The compact robotic joint of claim 1, wherein the electric motor
drives the gearbox in each of the first and third links, the
gearbox providing an output with a reduction of an operating speed
of the electric motor.
8. The compact robotic joint of claim 7, wherein each of the first
and third links further comprise a mechanism turning the output of
the gearbox about 90 degrees.
9. The compact robotic joint of claim 8, wherein the output turning
mechanism comprises a right-angle bevel gear pinion.
10. The compact robotic joint of claim 1, wherein the second link
comprises a main block upon which is mounted first and second
mechanisms for receiving power transmitted by the electric motors
of the first and third links, respectively, to rotate the first and
third links about the first and second axes.
11. The compact robotic joint of claim 10, wherein the first and
second mechanisms each comprise a bevel gear sector.
12. The compact robotic joint of claim 1, wherein each of the first
and third links further comprises an elongate housing in which the
electric motor and the gearbox are positioned with their outputs
provided along a longitudinal axis of the housing and wherein the
housing is substantially rigid relative to the longitudinal
axis.
13. A robotic joint, comprising: a first link comprising an
electric motor providing an output; a second link, wherein the
first link is mounted to the second link to allow rotation of the
first link about a first axis based on the output of the first link
electric motor; and a third link comprising an electric motor
providing an output, wherein the third link is mounted to the
second link to allow rotation of the third link about a second axis
based on the output of the third link electric motor and further
wherein the first axis is transverse to the second axis.
14. The robotic joint of claim 13, wherein the first and second
axes are proximal and are at right angles.
15. The robotic joint of claim 13, wherein the first and third
links each further comprise a gearbox driven by the output of the
electric motor, the gearbox being configured to provide an output
having a speed less than a speed of the output of the electric
motor.
16. The robotic joint of claim 15, wherein for each of the first
and third links the output of the electric motor and the output of
the gearbox are provided about a single axis and further wherein
each of the first and third links comprises a mechanism for
providing the gearbox output in a plane transverse to the single
axis.
17. The robotic joint of claim 16, wherein the transverse plane is
rotated about 90 degrees from the single axis and wherein the
mechanism comprises a right-angle bevel gear pinion.
18. A robotic joint having two rotational degrees of freedom,
comprising: a first joint assembly comprising a drive mechanism for
rotating a shaft; a second joint assembly; and a third joint
assembly comprising a drive mechanism for rotating a shaft, wherein
the first joint assembly and the third joint assembly are mounted
to the second joint assembly to rotate about first and second
rotation axes, respectively, when the shafts are rotated by the
drive mechanisms and wherein planes containing the first and second
rotation axes are substantially perpendicular.
19. The robotic joint of claim 18, wherein the central axis of the
shaft of the first joint assembly intersects and is substantially
perpendicular to the first rotation axis and the central axis of
the shaft of the third joint assembly intersects and is
substantially perpendicular to the second rotation axis.
20. The robotic joint of claim 19, wherein the second joint
assembly comprises surfaces for mating with first and second
right-angle gear pinions driven, respectively, by the shafts of the
first and third joint assemblies, whereby outputs of the drive
mechanisms is turned about 90 degrees to rotate the first and third
joint assemblies about the first and second rotation axes.
21. The robotic joint of claim 18, wherein the drive mechanisms
each comprise an electric motor driving a planetary gear assembly
that provides a gear reduction to rotate the shaft at a lower speed
relative to an output speed of the electric motor.
22. The robotic joint of claim 21 wherein the first and third joint
assemblies each comprise a rigid tubular housing in which the
planetary gear assembly and the electric motor are positioned.
23. The robotic joint of claim 21, wherein the first and second
rotation axes intersect or nearly intersect in the second joint
assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 10/757,797, filed Jan. 14, 2004, which claims the benefit of
U.S. Provisional Application No. 60/440,291, filed Jan. 14, 2003,
both of which are hereby incorporated by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] An animatronic supported walking system and method is
generally disclosed.
[0004] 2. General Background
[0005] Animatronic figures are those which employ electronics or
other mechanical, hydraulic, and pneumatic parts to animate
puppets. Animatronic characters are popular in entertainment venues
such as theme parks. For example, animatronic characters are often
employed in shows or rides found in a theme park. However, the
animatronic characters are generally in a fixed position. The
animatronic character's head or arms may move, but the character is
generally not capable of freely roaming or walking from one place
to another.
SUMMARY OF THE INVENTION
[0006] It is therefore desirable for such characters to walk freely
and independently through a theme park, parade or other venue and
interact with people and/or things. Furthermore, it is desirable
for such an animatronic character to appear quite realistic.
[0007] However, there are several specific problems to be solved
when developing such an animatronic walking figure.
[0008] First, real animals can and do fall over. However, in a
public venue such as a theme park where safety to each guest,
including small children, must be ensured, an animatronic figure
must not fall over. It is therefore an object to create a walking
robot which looks like an animal, but which cannot fall over and
injure guests.
[0009] Complex robotic systems also require electronics and
computers to function. A mobile system also requires a power supply
(battery, engine, etc). It is difficult to place these systems
inside the skin, (onboard) the actual robotic figure. If these are
placed outside the figure, we must find a way to hide these
components while maintaining the illusion that the figure is a real
animal. For example, electrical cords cannot be seen exiting the
figure.
[0010] Ideally, a single operator should command the animatronic
figure to move forwards, backwards, and to turn left and right. A
robot that looks like an animal might have over 40 individual
motors. This is too many for a single operator to simultaneously
control. A method or computer algorithm must therefore be created
which translates these simple commands into individual joint
trajectories that allow the system to walk.
[0011] Furthermore, the mechanical understructure of such
animatronic figures is necessarily robotic. That is, they are made
of joints, gears, actuators, hoses, electrical wiring, and
metallic, plastic, or composite structural elements. To make these
systems appear lifelike, they must be somehow covered, either by
clothing, or by an artificial skin, whether it be smooth, or
covered with fur, feathers or scales.
[0012] A supported walking system is thereby disclosed, comprising
a robotic walking figure and a wheeled support that at least
partially supports the robotic walking figure. The supported
walking system is driven and controlled by a human operator.
[0013] In one embodiment, the walking figure is designed to look
like a dinosaur, and the wheeled support is themed to look like an
old fashioned wooden cart. The result creates the illusion that the
dinosaur is pulling the cart, rickshaw style, when in fact the cart
partially supports the walking machine and houses a human driver,
computers, electronics, and batteries.
[0014] In one embodiment, the skin of the walking figure is
supported by a unique skeletal support system comprising
fiberglass, plastic and aluminum rings that are attached to each
other and to the walking machine skeleton via a combination of
rigid attachments and flexible rubber attachments. The effect is a
realistic-looking skin that floats over the mechanical skeleton
giving the appearance of a living animal.
[0015] Very few two-legged, freely walking robots have been created
at all, and all of these may be tipped over. By attaching a robotic
figure to a mobile cart, a number of issues associated with
creating a large walking figure are addressed,
[0016] In one embodiment, the walking figure is further attached to
cart via a "yoke." By attaching the walking figure to a cart via a
"yoke", the robot is partially supported, and prevented from
falling, ensuring the safety of people around it.
[0017] Furthermore, because the walking figure contains many
individual actuators, the electronics, computers, and power source
are too large to place inside the walking robot, The cart provides
a convenient location for these components. They are connected to
the walking robot by wiring that is hidden inside the yoke.
[0018] In an exemplary embodiment, the cart has two driven wheels
and a swiveling caster. This allows the cart to drive its own
weight and provides a stable base to support the walking robot.
This configuration also allows a human operator to drive the cart
using a simple joystick, to move forwards, backwards, to steer, and
to turn in place.
[0019] Computer algorithms automatically control the robot's
walking functions so that it may step forwards, backwards, and
sideways in synchronicity with the movements of the cart while
driving and turning at varying speeds.
[0020] The attached descriptions of exemplary and anticipated
embodiments of the invention have been presented for the purposes
of illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed. Many modifications and variations are possible in light
of the teachings herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a sketch of an exemplary embodiment of a supported
walking system.
[0022] FIG. 2 is a kinematic drawing of the supported walking
system.
[0023] FIGS. 3a and 3b are CAD drawings of the supported walking
figure without any theming elements.
[0024] FIG. 4 illustrates an exemplary embodiment of the skeletal
support structure.
[0025] FIG. 5 is a CAD drawing illustrating the rings which form
the skeletal support structure.
[0026] FIG. 6 is a close-up view illustrating an exemplary
embodiment of the skeletal support structure.
[0027] FIG. 7 is a CAD drawing of the skeletal support
structure.
[0028] FIG. 8 is a sketch of the skeletal support structure.
[0029] FIGS. 9a, 9b and 9c are CAD drawings of an exemplary
embodiment of a compact robotic joint.
[0030] FIG. 10 shows how an articulated structure may be created by
linking a series of exemplary joints together.
DETAILED DESCRIPTION OF THE INVENTION
[0031] In one aspect, a supported walking system is disclosed,
comprising a robotic walking figure and a wheeled support that at
least partially supports the robotic walking figure. The supported
walking system may be driven and controlled by a human operator. It
should be noted that the walking figure need not resemble any shape
presently known or recognizable. It may be entirely fanciful or
utilitarian, depending on the effect desired, or the use intended
for the system. Even though the embodiment depicted is a dinosaur
that may be presented in a theme park, the inventors in no way
intend this to be a limitation.
[0032] FIG. 1 is a skeleton of an exemplary embodiment of the
supported walking system. In one embodiment, the walking figure
(100) is designed to look like a dinosaur, and the wheeled support
(110) is themed to look like an old fashioned wooden cart. The
dinosaur (100) is attached to the cart with a yoke (120). The
resulting vehicle is designed to create the illusion that the
dinosaur (100) is pulling the cart (110), rickshaw style, when in
fact the cart partially supports the walking machine and also
houses a human driver, computers, electronics, and batteries.
[0033] Supported Walking Figure--Kinematics
[0034] The following is a brief kinematic description of one
embodiment of a supported walking system. In such an embodiment,
the supported walking system comprises of a two-legged walking
machine which is partially supported by a three-wheeled cart.
[0035] FIG. 2 is a kinematic diagram of one embodiment of a
supported walking system. The wheeled cart is shown as a square
frame (201). A first wheel (202) and a second wheel (203) are
mounted on each side to the side of the cart and rotate about axis
A. The first wheel (202) and second wheel (203) are powered. A
third wheel (205) is mounted to the front of the cart. The third
wheel (205) can roll and rotate freely about a vertical axis to
allow movement in any direction. A rigid yoke (204a-c) is attached
to the cart so that the yoke and the walking figure can pivot
freely about axis A. The yoke consists of two side beams (204a and
204b), and a curved member (204c) which fits around the walking
machine. A clevis (204d) is fixed rigidly to the curved member. To
this clevis is attached a link (205) which freely pivots relative
to the yoke about horizontal axis B. The body of the walking
machine (206) also has a clevis (206a) attached to it which pivots
freely about link (205) through axis C. In one embodiment, axes B
and C are perpendicular to each other. In this way, the body has
two degrees of freedom relative to the yoke. Rigidly attached to
the body are two additional clevises, (206b) and (206c). To these
clevises are attached the right and left legs of the walking
machine, respectively.
[0036] Considering the right leg, link (207) is attached to the
body through levis (206b) and is free to pivot about axis D. In a
current embodiment, this joint is powered. Link (208) is then
attached to link (207) so that it is free to pivot about axis E.
This joint is also powered. Axis D and E are perpendicular to each
other. Link (209) is attached via a pivot to link (208) so that it
may pivot about axis F, which is perpendicular to axes D and E.
This joint is powered. Link (210) is attached to link (209) such
that it may pivot about axis G. This joint is powered. Link (211)
is attached to link (210) such that it may pivot about axis H. In
the current embodiment, this link is constrained via a
parallelogram linkage (not shown) such that its orientation
relative to link (209) is fixed. Links (212) and (213) are attached
to link (211) such that they may pivot independently about I and J
respectively. These joints are also powered. The left leg is a
mirror image of the right leg.
[0037] The following is a more detailed description of the
mechanics in one embodiment of the supported walking system.
[0038] FIGS. 3a and 3b show illustrations of an exemplary
embodiment of a supported walking system.
[0039] In one aspect, a two-legged, robotic machine, (100) is
attached via a yoke (308) to a wheeled cart (110). As shown in
FIGS. 3a and 3b, the supported walking machine consists of two legs
(307), connected to a body (306). To this body are also attached a
neck (305), and a tail (303). The body of the walking machine
consists of a rigid tube. Each leg is a mechanism comprised of six
computer-controlled electric motors that operate a series of links,
and joints that allow the leg to arbitrarily position its foot at
any position and orientation relative to the body, within a
constrained volume. (Note that only one leg is shown in the
figures.) The neck (305) is a mechanism comprised of seven
computer-controlled electric motors operating a series of links and
joints. The neck supports a head (321), which itself contains a
number of additional motors. These motors operate for example, the
eyes, eyelids, mouth, and other facial features. Finally, a tail
mechanism is attached to the rear end of the body tube (303).
Similar in design to the neck, the tail is comprised of six
electric motors that operate a series of links and joints.
[0040] The cart consists of a steel frame (311), to which two drive
wheels (312) and a swiveling caster (310) are mounted. (Note that
only one driven wheel is shown in the figures.) The drive wheels
are each powered by an electric motor and a belt reduction
mechanism (322). The cart also houses electronics mounted in
enclosures (317), a battery pack power source (313), a joystick
(316), and a puppeting interface (315). A human operator sits in a
seat (314) and uses the joystick to drive the cart, and the
puppeting interface to control the movements of the walking
machine's body, neck and head. Even though circular wheels are
described herein, they could actually be other shapes (e.g. ovals)
to provide desired effects, and could be tracked systems as well.
The word "wheel" is to be understood in this way.
[0041] As the operator drives the cart, all of functions of the
walking machine are controlled automatically by a series of
computer algorithms to move synchronously with the cart. For
example, these algorithms calculate when and where each foot must
step, the speed and trajectory of each step and the body, neck,
head and tail motions tat accompany the stepping motions to create
realistic-looking walking. The operator may override some of these
automatically created motions, particularly those of the head and
neck, by using the puppeting interface during walking. Depending on
the use intended for the system, one or more functional arms or
other appendages may be included, these arms having functions such
as holding, pushing, lifting, etc. The tail and head could be
eliminated or replaced with other structures. To facilitate
operation of the system, the walking mechanism is equipped with
cameras (319) and microphones (320) mounted in the head. The
operator has a monitor (318) to view the video images, and
headphones to hear sounds that allow the operator to better
interact with guests standing near and talking to the system. The
operator may also be positioned away from the walking mechanism, in
a remote location, with remote control instrumentation. A wooden
decorative frame covers the entire cart, to give the illusion that
it is simply a traditional cart.
[0042] The cart and the walking machine are connected by a rigid
yoke (308) via three unpowered joints. This yoke is connected to
the cart via a hinge (309), and to the walking machine via a
two-axis "universal" joint, (304). The hinge at the cart allows the
walking machine to vary its height by extending its legs. The
universal joint allows the walking machine to pitch its body
forwards or backwards relative to the yoke, and to roll its body
side to side. The combination of these three joints allows the
walking machine to have a wide range of motion required for
realistic looking walking and motion, while preventing the system
from falling side-to-side, forwards, or backwards, even if all
motors were to completely shut down and power off. The yoke
attachment also incorporates a spring counterbalance mechanism
(322). This mechanism applies a rotational torque to the yoke about
hinge (309) that partially supports the weight of the walking
machine.
[0043] Walking Algorithm
[0044] A system and method of controlling the supported walking
system and causing the figure to walk is also disclosed.
[0045] In an exemplary embodiment, the supported walking system is
driven by a human operator using a common two-axis joystick. The
supported walking system can be viewed as a single vehicle with two
driven wheels and two legs, each of which has several independent
actuators.
[0046] The problem then, is how to generate a plurality of
independent motion profiles from two joystick inputs. For example,
it is a goal to create motions that make the system walk in a
straight line, while turning, and at varying speeds.
[0047] The operator uses the joystick input to drive the cart, and
the motions of the walking figure's legs are calculated by a
computer algorithm in response to the cart motions. A brief
description of this algorithm follows.
[0048] In an exemplary embodiment, a standard joystick that can be
moved along two axes, either left/right, or forward/backward is
used. The joystick directly controls the velocities of the two cart
wheels. For example, if the joystick is moved to the left only, the
left cart wheel will rotate backwards and the right wheel will
rotate forwards. The cart will then rotate about a vertical axis
directly between the two wheels, counterclockwise as viewed from
above. If the joystick is moved to the right only, the wheels move
in the opposite directions so that the cart will rotate clockwise
when viewed from above. The velocity of the wheels is controlled by
the distance the joystick is moved from its center position.
[0049] If the joystick is moved forward only, both wheels will
rotate forward at the same velocity, and the cart will move
forward. If the joystick is moved backward only, both wheels will
rotate backward at the same velocity, and the cart will move
backward.
[0050] If the joystick is moved at an angle, for example forward
and to the right, the above motions are combined linearly so that
the cart will move forward and turn to the right at the same time.
Again the speed of the motion is controlled by how far the joystick
is moved away from its center position.
[0051] The cart and the walking figure are attached by a rigid yoke
with three freely-rotating joints, and at all times, one or both of
the feet of the walking figure rest on the ground. Thus, the cart,
the yoke, the walking figure, and the ground on which the system
rests form one closed kinematic chain. (A closed kinematic chain is
any series of rigid links and joints which closes upon itself to
form a loop.)
[0052] As the cart moves (as driven by the operator), the walking
figure must move its legs relative to it's body in order to
maintain the integrity of the kinematic chain. If the legs do not
move appropriately, some portion of the kinematic chain will break,
typically by feet slipping or losing contact with the ground. For
example, if the cart moves forward, the feet must move backward
relative to the body, without rotating relative to the ground in
order that remain planted on the ground.
[0053] Sensors are incorporated on every moving joint in the cart,
yoke, legs and body of the supported walking system. Because the
dimensions of the system are known, the appropriate leg motions
necessary to maintain the integrity of the kinematic chain can
therefore be calculated. This is done using standard robotics
techniques.
[0054] It should be noted that by using these techniques, the body
of the walking figure can be moved even while the cart is
stationary. In particular, corresponding to the un-actuated joints
of the yoke, body can be tipped forward, as if bending forward to
eat from the ground. The body can also be rolled about a
longitudinal axis, or the body raised up or down to stand the
walking figure higher or lower. To command such motions of the
body, appropriate motions of the legs which both move the body and
which maintain the integrity of the closed kinematic chain formed
by the cart, yoke, walking figure and ground are calculated.
[0055] Because the legs of the walking figure have a limited range
of motion, at some point the walking figure must take steps in
order to accommodate the movement of the cart. To generate these
steps, a computerized walking algorithm is used. A reference line
is first chosen. In an exemplary embodiment, the reference line is
a vertical line that passes through the pivots which attach the
yoke to the figure. The walking figure uses this reference line and
moves relative to this line. This line passes vertically through
the center of the walking figure body.
[0056] As an example, consider a forward step. If the cart is moved
forward, the body of the walking figure will also move forward and
the feet will remain stationary on the ground, but will move
backward relative to the reference line. When either foot moves
behind the reference line, the algorithm commands the most rearward
foot to move to a specified distance in front of the reference
line. This distance is a function of the cart velocity. Larger cart
velocities will therefore generate larger steps. The foot which
remains on the ground cannot step until the other foot has safely
planted on the ground, at which point if it is behind the reference
line, it will step forward. The trajectory of the leg while in the
air is partially pre-determined. The height of the step is
pre-determined, while the step length and step time are functions
of the cart velocity when the step is commanded. The exact
trajectory of the step is calculated as a function of these
parameters.
[0057] At the conclusion of a step, when the foot comes in contact
with the ground, the vertical motion of the foot is stopped when a
preset foot/ground force threshold is exceeded. This allows the
figure to walk on uneven surfaces by stopping the foot's vertical
motion when it meets the ground instead of at a prescribed vertical
position. The force applied is sensed indirectly by reading the
current commanded to actuators in the legs. Since current applied
to these motors is proportional to motor torque, an estimate of the
force applied to the ground can be made.
[0058] If the cart were, for example, turning left while moving
forward, then the foot would be placed both forward and to the left
of the reference line, again as a function of the cart
velocity.
[0059] In this way, steps can be made in any combination of
forward/backward and left/right in order to steer the cart and
walking figure. The steps so generated result in walking motions
which give the illusion that the walking figure is in fact pulling
the cart.
[0060] In another embodiment, a scripting language can be used to
coordinate the movements of the walking figure (100). The scripting
language can be a computer language that allows the user to provide
a set of commands to the walking figure (100). In one embodiment,
the scripting language provides for a combination of puppetry and
fixed shows. Puppetry refers to a user's ability to provide
interactive commands to a puppet. In addition, a fixed show is a
predetermined sequence of movements that a robotic figure can be
programmed to perform without interaction from the user. The
scripting language allows Lucky to simultaneously respond to
puppeting instructions from a user's input and to perform a fixed
show. For example, the walking figure (100) can be preprogrammed to
sneeze at certain time intervals. At the same time the user can
provide interactive instructions for the movement of the walking
figure (100).
[0061] One potential application of the scripting language is for
use with robotics on an assembly line. Many products are
manufactured with robots that perform predetermined movements to
accomplish a task on the assembly line. However, part of the
assembly process may require some human interaction that cannot be
automated. A user may want the flexibility to perform quality
control on the product at the same time that the robot is
assembling it. For instance, as the left arm of the robot performs
a predetermined assembling routine on a product, the right arm can
at the same time receive instructions from a human user to perform
some quality control tests.
[0062] In addition, the scripting language can smooth out the
trajectories of the movements of the walking figure (100). The
scripting language provides robots with the ability to make
smoother movements than can ordinarily be provided for. Traditional
robots have awkward movements and sometimes even respond with
inaccurate movements when receiving an unfamiliar command. The
scripting language solves this problem by providing a trajectory
even in the case that a command is unfamiliar. In one embodiment,
the scripting language is applied in settings where the precise
movements of a robot are critical for productivity and safety. For
instance, in a hazardous waste setting, an inaccurate command by a
user to a robot can result in harmful spillage of waste. If the
robot was instructed to move in a relatively smooth trajectory,
there would be less risk of accidental spillage. The use of the
scripting language to produce smoother movements in the robotics
field can be applied to a wide variety of fields where precision is
of the utmost importance.
[0063] The scripting language can also provide for real time
optimization. Previous scripting languages allocated memory and
other computer resources as needed. These allocations can block the
computer for arbitrary lengths of time. If memory is not allocated
properly, the robot stops functioning. The scripting language here
has a memory allocation method that prevents the computer from
being blocked. Real time performance means that the task must be
performed in a specified period of time. In one embodiment, the
real time optimization technique is used with robots to ensure that
robots do not unnecessarily stop functioning for a period of time.
For instance, if a robot that is carrying hazardous waste even
momentarily stops functioning, spillage may result.
[0064] Further, the scripting language can include an improved
transformation technique. When a user provides a command to a robot
instructing the robot to move in a certain way, a mathematical
transformation between the user's instruction and the actual joint
movements necessary to carry out the user's instruction must take
place. The scripting language provides an interface that allows
users to intuitively instruct the robot to move in a certain
direction. Further, the interface simplifies the complexity of
combining motions such as vertical and horizontal motions. For
example, the robot may respond to an instruction of "walk straight"
as opposed to "lift left leg vertically y feet, move left leg
horizontally x feet".
[0065] One of ordinary skill in the art will recognize that the
techniques that are used by the scripting language are not limited
to scripting languages as opposed to other computer languages.
These techniques can also be employed in different types of
computer languages. Further, the scripting language is not limited
to a particular type of graphical user interface ("GUI"). Any
number of GUIs can be used in conjunction with the scripting
language. Any method, hardware, software, or circuitry needed to
provide computerized instructions to the walking figure (100) can
be utilized. One of ordinary skill in the art will recognize that
any controller or memory needed to implement the scripting language
can be utilized. Further, one of ordinary skill in the art will
recognize that the scripting language can be stored within the
walking figure (100) itself or at a remote location from which
instructions are sent to the walking figure (100). As discussed
above, the scripting language can be used in other applications
besides the supported walking system.
[0066] Skeletal Support Structure & Skin
[0067] Further completing the overall image of a realistic looking
robotic or animatronic character is the skin and skeletal
structure.
[0068] Traditionally, animatronic figures have used hydraulic
actuators, because of their very high power to size ratio. However,
hydraulic systems have several disadvantages. Hydraulic oil tends
to leak from these systems, damaging delicate skins and other
outside coverings. They also require pressurization at pressures
between 500 and 6000 psi. These high pressure systems must be kept
away from people because ruptures in pressurized hydraulic lines
can cause dangerous fluid jets. Hydraulic systems also support
force on columns of hydraulic oil, which are necessarily compliant.
This compliance limits the bandwidth of response of hydraulic
systems. Finally, hydraulic systems require a significant
infrastructure of pumps, oil reservoirs, manifolds, valves and
accumulators.
[0069] It is, therefore, advantageous to use electric motors for
robotics and animatronic figures. Electric motors, however,
typically have a lower power to size ratio than do hydraulic
actuators. Therefore, the weight of an electrically driven robotic
or animatronic system becomes a critical issue and must be kept as
low as possible.
[0070] There are several other problems which make the development
of an understructure to support animatronic skins difficult. Real
creatures have very large ranges of motion of their joints. This
means to create realistic motions, skins and the structures
supporting them must accommodate significant stretch and
compression. Real creatures have a large number of
degrees-of-freedom, especially in features such as a neck or a
tail. It is costly to have as many joints in an animatronic figure
as would exist in the real creature. So it is advantageous if the
skin and supporting structure can enhance the look of the figure by
making it appear as though there are more joints than are in the
underlying mechanism. Real creatures are biological and therefore
have complex outer shapes. A skin and supporting structure must
maintain these shapes while looking realistic despite considerable
movement, stretch and compression.
[0071] Therefore, it is advantageous for the skin and its
supporting structure to occupy as little space as possible. Because
the robotic mechanism strength is related to its size, if the skin
and its supporting structure occupy a great deal of space, very
little is left over for the mechanism, making it difficult to make
sufficiently strong and rigid. Finally, the skin and its supporting
structure should be easy to manufacture.
[0072] Therefore, a mechanism which will support animatronic skins
through large ranges of motion with significant flexing and
compression is needed. It is further desirable for the skin support
mechanism to hide the underlying robotic structure. It is further
desirable for the skin support structure to accommodate complex
shapes. It is further desirable for the skin support structure to
be extremely lightweight. It is further desirable for the skin
support structure to occupy a small amount of space between the
internal robotic mechanism and the skin itself. Finally, it is
desirable that the skin support structure be simple to
manufacture.
[0073] A skeletal support structure for a mechanical or robotic
figure is therefore also disclosed. The skeletal support structure
is a system that supports skins for animatronic figures which
allows for a large range of motion, is compact in size, is
lightweight, may be made in complex shapes, and is easy to
manufacture. In an exemplary embodiment, a painted foam-latex skin
covers the skeletal support structure.
[0074] FIGS. 4-8 illustrate exemplary embodiments of a skeletal
support structure and overlying skin. FIG. 4 illustrates the
realistic looking result achieved by the skin and skeletal
structure in one embodiment.
[0075] In the embodiment shown in FIG. 4, the walking FIG. 100 is
in the form of a dinosaur pulling a cart 110. The dinosaur is
attached to the cart using a yoke 120. A painted foam latex skin
130 covers the skeletal support structure of the walking FIG. 100.
The skin 130 is fabricated by pouring foam-latex into molds that
represent the outside shape of the desired character. In the case
of a dinosaur, the neck and tail portion of the dinosaur should
move flexibly in many directions. In order for the dinosaur's
movements to look real, a unique skeletal structure is used for the
neck and tail portions. The effect is a realistic-looking skin that
floats over the mechanical skeleton giving the appearance of a
living animal.
[0076] The skeletal support structure comprises a plurality of
rings that are attached to each other and at various points to the
figure. The rings are attached to each other using flexible
attachments, and to the figure at various locations using rigid or
fixed attachments.
[0077] In one embodiment, the skin is supported by a skeletal
support system comprising fiberglass, plastic and aluminum rings
that are attached to each other and to the walking machine skeleton
via a combination of rigid attachments and flexible rubber
attachments.
[0078] FIG. 5 is an illustration of the skeletal support structure
as found underneath the system illustrated in FIG. 4. Note that the
head and tail portions are covered with a structure made of a
plurality of rings. FIG. 6 is an enlarged view of the skeletal
support structure in the tail. FIG. 7 is an illustration of the
rings themselves. The rings are attached to each other by flexible
elements. In our current embodiment, we have used pieces of latex
surgical tubing. They are oriented to allow simple attachment to
the rings using plastic tie wraps. This orientation also allows the
rings to compress and expand upon one another with very little
force. They may also rotate relative to each other, to allow a tail
or neck to twist about its longitudinal axis. The tube orientation,
however, tends to prevent the rings from shifting or shearing
relative to each other.
[0079] In one embodiment, the rings are fabricated by first making
a computer scan of the tooling used to mold the flexible skin.
Then, in a CAD program, the rings are designed by "slicing" the
computer scanned surface. The rings are, for example, CNC milled
from panels made by laminating carbon fiber sheeting to a nomex
honeycomb core. These types of panels are commonly used in the
aircraft industry as they are very stiff for their weight. By
assembling the structure from rings made in this way, the complex
skin shape is ensured to fit the structure which supports it.
Furthermore, due to the thinness of the rings and flexibility of
the flexible elastic tubing used to join them, the structure can
accommodate a large degree of flexing and compression, as required
when the underlying joints move through a large range of
motion.
[0080] To mount the ring structure to the underlying tail
mechanism, one ring per link of the structure is mounted to each
link of the tail mechanism. In this way, the ring structure floats
over the tail mechanism. In one embodiment, these rings are made
from aluminum for strength.
[0081] FIG. 8 shows a schematic representation of this system
mounted to a tail with three joints and four mechanical links.
Rings (801), (802), (803) and (804) are mounted to tail links
(805), (806), (807) and (808) respectively. The remaining rings,
examples of which are labeled (809), are mounted to each other and
to the fixed rings, but otherwise allowed to float over the tail
mechanism. To enable the skin to slide smoothly over the ring
structure, a Lycra.RTM. sock is mounted over the rings and
underneath the skin. The rings, covered with Lycra.RTM., produce a
relatively smooth, continuous surface to support the tail skin,
hiding the underlying tail mechanism and giving the illusion that
there are many more than three actuated joints.
[0082] Compact Robotic Joint
[0083] Further in accordance with the supported walking system as
has been described so far, a novel robotic joint is disclosed that
is compact in size, incorporates two degrees-of-freedom at right
angles to each other, and may be powered using electric
actuators.
[0084] As mentioned earlier, it is advantageous to use electric
motors for robotics and animatronic figures. However, electric
motors operate most efficiently at high speeds. Since most robotic
and animatronic systems have desired joint speeds many times less
than the optimal operating speed of an electric motor, reduction
gearing is required. It is also the case that the form factor of
electric motors does not lend itself to simple packaging solutions
to fit into the envelope required by many animatronic figures.
[0085] Specifically, it is often advantageous to turn the output of
an electric motor by 90 degrees to optimally package it in a
slender animatronic arm, neck or tail. Furthermore, it is
advantageous to provide joints whose axes intersect or very nearly
intersect, and are at right angles to each other. This is because
the joints of animals' backs, necks, and tails consist of vertebrae
which bend in at least two directions and it is necessary to
represent these joints in an animatronic figure.
[0086] A compact robotic joint is therefore provided. The compact
robotic joint has two rotational degrees-of-freedom where the axes
of rotation intersect or nearly intersect and are at right angles
with one another. The compact robotic joint may be powered using
electric motors. The compact robotic joint further accommodates a
significant gear reduction.
[0087] FIGS. 9a, 9b, 9c and 10 illustrate an exemplary embodiment
of the compact robotic joint.
[0088] The joint consists of three links which may be actuated to
move relative to each other. A first link (Link 1) moves relative
to a second link (Link 2) along axis A. A third link (Link 3) moves
relative to the second link along axis B. Note that in this
embodiment, first and third links are identical. While this need
not he the case, making these links identical reduces manufacturing
and inventory costs and is one of the features of this joint.
[0089] The first link (Link 1) is comprised of an electric motor
(902) to the rear of which is attached a rotary encoder (901) to
measure motor position. A planetary gearbox (903) is attached to
the front of the motor. This assembly is attached to clevis (908)
via an adapter plate (904). A coupler shaft (905) is rigidly
attached to the shaft of the gearbox and a right-angle bevel gear
pinion (907) is rigidly fixed to the coupling using a dowel pin
(not shown). The coupler shaft is rotatably mounted into the clevis
using a combination of rotary and thrust bushings (906).
[0090] The second link (Link 2) is comprised of a main block (914),
to which is mounted bevel gear sectors (911) and (918) and motion
stops (909) and (919). Flanged bushings (910), (913), (915), and
(917) are also pressed into the first link.
[0091] The first link is rotatably mounted to the second link using
a shaft (916). The third link is similarly rotatably mounted to the
second link using a shaft (912).
[0092] Power is transmitted from the first link to the second link
through pinion (907) to gear (911). By controlling the orientation
of motor (902), the orientation of the second link is controlled
relative to the first link. Similarly, power is transmitted from
the third link to the second link through pinion (921) to gear
(918). By controlling the position of motor (926), the orientation
of the third link is controlled relative to the second link.
[0093] A controllable, articulated structure may be created by
linking a series of these joints together, see FIG. 10.
[0094] While the system has been described in detail and with
reference to specific embodiments, it will be apparent to those
skilled in the art that various changes and modifications can be
made therein without departing from the spirit and scope thereof.
Thus, it is intended that the claimed invention not be limited to
any specific description above, and that it includes modifications
and variations provided they come within the scope of the appended
claims and their equivalents.
[0095] Other embodiments and implementations may be utilized and
structural and functional changes may be made without departing
from the respective scope of the claimed invention. The attached
description of exemplary and anticipated embodiments have been
presented for the purposes of illustration and description. They
are not intended to be exhaustive or to limit the invention to the
precise forms disclosed.
[0096] Many modifications and variations are possible in light of
the teachings herein. Many other forms of the invention exist, each
differing from the others in mattes of detail only. The invention
is to be determined by the following claims.
* * * * *