Dynamic balancing mobile robot

• US 7,847,504 B2
• Filed: 10/10/2007
• Issued: 12/07/2010
• Est. Priority Date: 10/10/2006
• Status: Active Grant

• Current Assignee: Carnegie Mellon University
• Original Assignee: Carnegie Mellon University
• Inventors: Hollis, Ralph L.
• Primary Examiner(s): Benson; Walter
• Assistant Examiner(s): Paul; Antony M
• Application Number:
  US11/973,685
• Publication Number:
  US 20080084175A1
• Time in Patent Office: 1,154 Days
• Field of Search: 318/568.12, 318/568.11, 901/1, 180/252
• US Class Current: 318/568.12
• CPC Class Codes: B25J 5/007 mounted on wheels
• CPC Class Codes: G05D 1/0891 specially adapted for land vehicles

Abstract

A mobile robot having a height-to-width ratio approximating a normal adult human balances and maneuvers atop a single, spherical wheel. Dynamic balancing techniques incorporating fiber-optic gyroscopes and micro-electromechanical accelerometers measure a number of parameters which, along with data from motor shaft encoders, enable a computer to calculate the forces needed to be applied to the spherical wheel to maintain the robot upright as it maneuvers or remains in place.

Claims

1. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground and the sole support for said platform, said platform configured such that said mobile robot has a height-to-width ratio approximating an average adult human, said platform carrying;

a sensor;

a motor;

means for coupling a torque generated by said motor to said wheel;

a control system responsive to said sensor for controlling the torque provided by said motor to said wheel; and

a power supply for supplying power to said robot.

2. The robot of claim 1 wherein said wheel comprises a rubber-coated metal ball.

3. The robot of claim 1 wherein said wheel is comprised of a urethane-coated, hollow, aluminum sphere.

4. The robot of claim 1 wherein said sensor comprises a sensor for providing pitch and roll angles and rates.

5. The robot of claim 1 additionally comprising a plurality of motors positioned above said wheel, and a plurality of means for coupling, each for coupling a torque generated by one of said plurality of motors to said wheel.

6. The robot of claim 5 wherein each of said means for coupling comprises a roller in contact with said wheel and a belt connecting said roller to a motor.

7. The robot of claim 6 wherein rollers are positioned to operate in pairs located opposite one another on said wheel.

8. The robot of claim 1 wherein said control system comprises an inner control loop for controlling wheel velocity and an outer control loop for controlling stability of the robot.

9. The robot of claim 1 additionally comprising a plurality of legs carried by said platform and means for automatically moving said legs between a deployed position for supporting said platform when said platform is un-powered, and a stowed position when said platform is powered.

10. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground and the sole support for said platform, said platform carrying;

a plurality of motors;

means for coupling torques generated by said motors to said wheel;

a plurality of gyroscopic sensors and accelerometers for providing pitch, pitch rate, roll, roll rate, and yaw rate data;

a control system responsive to said plurality of sensors for generating signals for controlling the torques developed by said plurality of motors, said control system implementing an inner control loop for controlling wheel velocity and an outer control loop for controlling stability of the robot; and

a power supply for supplying power to said robot.

11. The robot of claim 10 additionally comprising a plurality of shaft encoders each responsive to one of said plurality of motors for producing shaft position information, said control system further responsive to said shaft position information.

12. The robot of claim 10 additionally comprising extrinsic sensors for producing information about said robot'"'"'s environment, said control system further responsive to said extrinsic sensors.

13. The robot of claim 10 additionally comprising a yaw motor and an absolute shaft encoder responsive to said yaw motor, said control system responsive to said absolute shaft encoder for generating signals for controlling a torque developed by said yaw motor.

14. The robot of claim 10 wherein said plurality of motors is positioned above said wheel, and wherein each of said means for coupling comprises a roller in contact with said wheel and a belt connecting said roller to a motor.

15. The robot of claim 14 wherein rollers are positioned to operate in pairs located opposite one another on said wheel.

16. The robot of claim 10 additionally comprising a plurality of legs carried by said platform and means for automatically moving said legs between a deployed position for supporting said platform when said platform is un-powered, and a stowed position when said platform is powered.

17. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground, said platform carrying;

a plurality of motors;

means for coupling forces generated by said plurality of motors to said wheel;

a plurality of sensors;

a control system responsive to said plurality of sensors for controlling the forces provided by said motors to said wheel;

a plurality of legs, said legs being moveable between a stowed position and a deployed position;

means for moving said plurality of legs, said means for moving being responsive to said control system; and

a power supply for supplying power to said robot.

18. The robot of claim 17 additionally comprising a wheel on the end of each of said plurality of legs for contacting the ground.

19. The robot of claim 17 additionally comprising a switch on the end of each of said plurality of legs for indicating contact with the ground.

20. The robot of claim 19 additionally comprising a plurality of limit switches for indicating that said legs are in the stowed position.

21. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground, said platform configured such that said mobile robot has a height-to-width ratio approximating an average adult human, said platform carrying;

a sensor;

a plurality of motors positioned above said wheel;

a plurality of means for coupling, each for coupling a force generated by one of said motors to said wheel, wherein each of said means for coupling comprises a roller in contact with said wheel and a belt connecting said roller to one of said plurality of motors;

means for coupling a torque generated by said motor to said wheel;

a control system responsive to said sensor for controlling the torque provided by said motor to said wheel; and

a power supply for supplying power to said robot.

22. The robot of claim 21 wherein rollers are positioned to operate in pairs located opposite one another on said wheel.

23. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground, said platform configured such that said mobile robot has a height-to-width ratio approximating an average adult human, said platform carrying;

a sensor;

a motor;

means for coupling a torque generated by said motor to said wheel;

a control system responsive to said sensor for controlling the torque provided by said motor to said wheel;

a plurality of legs carried by said platform and means for automatically moving said legs between a deployed position for supporting said platform when said platform is un-powered, and a stowed position when said platform is powered; and

a power supply for supplying power to said robot.

24. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground, said platform carrying;

a plurality of motors;

means for coupling forces generated by said motors to said wheel, said plurality of motors is positioned above said wheel, and wherein each of said means for coupling comprises a roller in contact with said wheel and a belt connecting said roller to a motor;

a plurality of gyroscopic sensors and accelerometers for providing pitch, pitch rate, roll, roll rate, and yaw rate data;

a control system responsive to said plurality of sensors for generating signals for controlling the forces developed by said plurality of motors, said control system implementing an inner control loop for controlling wheel velocity and an outer control loop for controlling stability of the robot; and

a power supply for supplying power to said robot.

25. The robot of claim 24 wherein rollers are positioned to operate in pairs located opposite one another on said wheel.

26. A dynamic balancing mobile robot, comprising:

a single spherical wheel;

a platform positioned above and resting on said wheel such that said single wheel is the sole contact point between said platform and the ground, said platform carrying;

a plurality of motors;

means for coupling forces generated by said motors to said wheel;

a plurality of gyroscopic sensors and accelerometers for providing pitch, pitch rate, roll, roll rate, and yaw rate data;

a control system responsive to said plurality of sensors for generating signals for controlling the forces developed by said plurality of motors, said control system implementing an inner control loop for controlling wheel velocity and an outer control loop for controlling stability of the robot;

a plurality of legs carried by said platform and means for automatically moving said legs between a deployed position for supporting said platform when said platform is un-powered, and a stowed position when said platform is powered; and

a power supply for supplying power to said robot.