In-Line Legged Robot Vehicle and Method for Operating

• US 20110231050A1
• Filed: 03/21/2011
• Published: 09/22/2011
• Est. Priority Date: 03/22/2010
• Status: Active Grant

• Current Assignee: John R. Goulding
• Original Assignee: John R. Goulding
• Inventors: Goulding, John R.
• Granted Patent: US 8,457,830 B2
• Time in Patent Office: Days
• US Class Current: 701/26
• CPC Class Codes: B25J 5/00 Manipulators mounted on wheels or on carriages B25J1/00 takes precedence; programme-controlled manipulators B25J9/00 ; vehicle aspects B60, B62, e.g. remote-controlled steering for motor vehicles B62D1/24; control of position of vehicles G05D1/00
• CPC Class Codes: B25J 9/1633 compliant, force, torque control, e.g. combined with position control
• CPC Class Codes: B25J 9/1674 characterised by safety, monitoring, diagnostic
• CPC Class Codes: B62D 57/00 Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track sledges B62B; motor sledges B62M
• CPC Class Codes: B62D 57/02 with ground-engaging propulsion means, e.g. walking members
• CPC Class Codes: B62D 57/024 specially adapted for moving on inclined or vertical surfaces endless-track vehicles for ascending or descending stairs B62D55/075; hand-carts with provision for travelling up or down stairs B62B5/02
• CPC Class Codes: B62D 57/032 with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid B62D57/024 takes precedence
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• CPC Class Codes: G05D 1/0891 specially adapted for land vehicles
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

A legged vehicle includes a body, wherein the body includes a major axis corresponding to a primary direction of travel; a plurality of leg mechanisms attached to the body, wherein each leg is attached at its proximal end at one or more discrete attachment points, wherein the attachment points are arranged in-line, one behind the other, with respect to the body, each of the legs including actuators attached between the legs and the body and between adjacent leg members, said legs being actuated for movement of a distal end in three dimensions; a control system in communication with the leg mechanisms to coordinate movements of the leg mechanisms according to approximately single track foot placement, and movement of the legged vehicle in three dimensions over the ground; and a power source connected to and driving the control system components and the plurality of actuators and joints which drive the legs.

Claims

1. A legged vehicle comprises:

a frame, wherein the frame includes a major axis corresponding to and generally parallel to a forward/backward direction of travel;

a plurality of jointed leg mechanisms attached to the frame, one behind the other, wherein each leg is attached at its proximal end at one or more discrete attachment points, wherein the attachment points are arranged substantially parallel to the major axis of the frame and the forward/backward direction of travel, each of the legs including actuators attached between the legs and the frame and between adjacent leg members, said legs being actuated for movement of a distal end in three dimensions, wherein forward/backward movement of the legged vehicle is according to approximately single track foot placement;

a control system in communication with the leg mechanisms and receiving sensed data to determine possible future states of the legged vehicle and to coordinate movements of the leg mechanisms and frame, and movement of the legged vehicle in three dimensions over the ground; and

a power source connected to and driving the control system components and the plurality of actuators which drive the legs.

2. The legged vehicle of claim 1, wherein the number of legs is three.

3. The legged vehicle of claim 1, wherein the number of legs is more than three.

4. The legged vehicle of claim 1, wherein each of the plurality of legs includes a foot at the distal end.

5. The legged vehicle of claim 1, wherein the feet include at least one of plates, skids, spikes, wheels, skates, skies, slides, floats, hydroplanes, and fingers.

6. The legged vehicle of claim 1, wherein the frame is a single piece unit.

7. The legged vehicle of claim 1, wherein the frame is jointed and includes two or more segments, each having a major axis corresponding to and generally parallel to a forward/backward direction of travel.

8. The legged vehicle of claim 1, wherein

control of movement of the frame and leg-positioning along the major axis corresponding to the pitch axis is decoupled from the movement of the frame and leg-positioning normal to the major axis and corresponding to the roll axis.

9. The legged vehicle of claim 1, wherein the control system further comprises

at least one accelerometer and at least one gyroscope mounted on the frame and in communication with the control system, the control system receiving sensed data from the at least one accelerometer and at least one gyroscope to sense velocity, acceleration, attitude, and gravitational forces.

10. The legged vehicle of claim 1, wherein each leg mechanism includes position-measuring components providing feedback to the control system.

11. The legged vehicle of claim 1, wherein each leg mechanism includes force-measuring components providing feedback to the control system.

12. The legged vehicle of claim 1, wherein each leg mechanism includes torque-measuring components providing feedback to the control system.

13. The legged vehicle of claim 1, wherein legged movement of the vehicle is according to a gait model, wherein at least one gait model is stored in the read-only memory of the control unit.

14. The legged vehicle of claim 1, wherein the control system further comprises an omni-directional guidance, navigation, and control algorithm.

15. The legged vehicle of claim 1, wherein the forward velocity and body height parameters are adapted for the at least one gait model using sensed or a priori ground terrain data.

16. The legged vehicle of claim 1, wherein the movement range for each of the legs defines a working envelope, each of the feet having sufficient reach and movement range in length, width and height, relative to the frame to position two feet generally perpendicular to the major axis of the frame, with one foot positioned to the left of and one to the right of the projected center of gravity of the frame to provide stability in the roll axis.

17. The legged vehicle of claim 1, wherein the movement range for each of the legs defines a working envelope, each of the feet having sufficient reach and movement range in length, width and height, relative to the frame to position the first, second and third feet in a triangular tripedal stance, wherein the projected center of gravity of the frame is located within the tripedal stance, providing stability in both the pitch and roll axes.

18. The legged vehicle of claim 1, wherein the movement range for each of the legs provides range-of-motion overlap in length, width and height of the working envelopes of each adjacent foot, one in front of and one behind the other.

19. The legged vehicle of claim 1, wherein the feet of two adjacent legs, one in front of and one behind the other, are positionable side-by-side to form a generally bipedal stance along a center of pressure line generally normal to the frame and normal to the line of motion to achieve a bipedal stance.

20. The legged vehicle of claim 1, further comprising:

a control unit having an operator interface, in communication with the control system, the control system receiving sensed data from the operator.

21. The legged vehicle of claim 20, wherein the operator interface components provide at least steering angle, throttle and braking inputs into the control system.

22. The legged vehicle of claim 20, wherein inputs to the operator interface control stability of balance in the roll axis.

23. A method of operating a legged vehicle including a frame having a major axis corresponding to a forward/backward direction of travel;

a plurality of leg mechanisms attached to the frame, one behind the other, wherein each leg is attached at its proximal end at one or more discrete attachment points, wherein the attachment points are arranged substantially parallel to the major axis of the frame and the forward/backward direction of travel, each of the legs including actuators attached between the legs and the frame and between adjacent leg members, said legs being actuated for movement of a distal end in three dimensions, wherein forward/backward movement of the legged vehicle is according to approximately single track foot placement;

a control system in communication with the leg mechanisms and receiving sensed data to determine possible future states of the legged vehicle and to coordinate movements of the leg mechanisms and frame, and movement of the legged vehicle in three dimensions over the ground; and

a power source connected to and driving the control system components and the plurality of actuators and joints which drive the legs, the method comprising the steps of;

developing reaction forces, torques, and thrusts in a stance phase wherein leg/foot-to-ground interaction is transferred through the leg to stabilize the frame in the pitch, roll, and yaw axes and to propel the frame in the x, y, and z axes, respectively, the foot/distal end of the leg being generally stationary with respect to the ground during the stance phase and moving generally opposite to the major direction of frame motion, of a monopedal stance, a bipedal stance and a tripedal stance, according to the control system;

unloading reaction forces through the leg/foot in a stance-to-flight phase wherein the foot is lifted off the ground, controlling leg velocities, according to the control system;

repositioning the leg/foot in a flight phase wherein the distal end of the leg/foot is moved generally in the same direction as the frame and generally at a faster rate, relative to the ground, as the major direction of frame motion, controlling foot placement and leg movement to maintain an upright posture and meet foot placement constraints and desired trajectory requirements for the frame and legged vehicle, according to the control system; and

placing the leg/foot to the ground and developing reaction forces, torques, and thrusts in a flight-to-stance phase;

wherein movement of each leg includes each of the four phases for each leg.

24. The method of operating the legged vehicle of claim 23, further comprising:

during the flight phase for at least one leg, controlling leg movement, torque, extension velocity and retraction to use the mass of the at least one leg to impart forces and torques to the frame in at least one dimension or axis.

25. The method of operating the legged vehicle of claim 23, further comprising the steps of:

decoupling leg-positioning along the length of the frame, corresponding to the major axis, from the leg-positioning along the width of the frame and normal to the major axis and parallel to the ground; and

controlling stability of balance over time in the roll direction primarily, wherein the plurality of leg mechanisms attached to the frame, one behind the other, along the major axis reduce the need for pitch control.

26. The method of operating the legged vehicle of claim 23, further comprising:

leaning the vehicle into a desired direction of turn, wherein a projected center of gravity is laterally displaced inwardly from a point within a triangle defined by foot contact with the ground, wherein a torque is developed around the roll axis in the direction of the lean;

displacing one or more feet normal to and spatially distant from the projected center of gravity in the opposite direction of the lean to develop an outward torque about the roll axis to counteract the inward lean, wherein the trajectory becomes a curved line.

27. The method of operating the legged vehicle of claim 23, further comprising:

developing torque from at least one leg or a combination of two or more legs to rotate the frame along a curved trajectory.

28. The method of operating the legged vehicle of claim 23, further comprising:

sensing with at least one of a gyroscope and accelerometer an induced roll condition from an external force; and

leaning the vehicle into the direction from which the external force is applied, wherein the roll condition is neutralized, according to the control system.