Gait generation system of legged mobile robot

• US 6,301,524 B1
• Filed: 06/10/1998
• Issued: 10/09/2001
• Est. Priority Date: 07/25/1996
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Takenaka, Toru
• Primary Examiner(s): Gordon, Paul P.
• Assistant Examiner(s): CABRERA, ZOILA E
• Application Number:
  US09/095,438
• Time in Patent Office: 1,217 Days
• Field of Search: 700/245, 700/250, 318/568.12
• US Class Current: 700/245
• CPC Class Codes: B62D 57/02 with ground-engaging propulsion means, e.g. walking members
• 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

Abstract

In a gait generation system for a legged mobile robot, in particular a legged mobile robot having a body and a plurality of legs links each connected to the body through a joint, it is configured such that gaits comprising motion parameters and floor reaction force parameters are varied freely on a real-time basis during walking. In order to effect this, various standard gaits have been prepared on an off-line computer and an approximated value such as a weighted average thereof is calculated in response to a demand for gait, and gaits are generated. Moreover, the gaits are corrected using an inverted pendulum model such that positions and the velocities are continuous at the boundary of the gaits. With the arrangement, it becomes possible to generate gaits having the floor reaction force freely on a real-time basis to effect a stride or turning angle as desired. It also becomes possible to make the displacements and velocities of various portions of the robot continuous at the boundary of the gaits. In addition, it becomes possible to control the legged mobile robot based on the gaits thus generated on a real-time basis.

Claims

1. A system for generating a gait of a legged mobile robot having at least a body and a plurality of leg links each connected to the body through a joint comprising:

a. standard gait storing means for storing, in memory, a plurality of standard gaits, including at least a gait to start walking, a gait for constant speed walking, and a gait to stop walking, each comprising a set of parameters including a parameter relating to a floor reaction force;

b. gait demanding means for making a demand for gait; and

c. gait generating means for generating an approximated gait which satisfies the demand for gait by selecting one or a plurality of the standard gaits in response to the demand for gait, and by conducting approximation on at least one of the parameters of the selected standard gait or gaits.

2. A system according to claim 1, wherein said gait generating means generates the approximated gait by calculating a weighted average of at least one of the parameters of the selected gaits.

3. A system according to claim 1, wherein said gait generating means generates the approximated gait by using a parameter sensitivity of one of the parameters to another of the parameters of the selected gait or gaits.

4. A system according to claim 1, wherein said gait generating means generates the approximated gait by calculating a weighted average of at least one of the parameters of the selected gaits and by using a parameter sensitivity of one of the parameters to another of the parameters of the selected gait or gaits.

5. A system according to claim 3, wherein said gait generating means includes:

d. change amount determining means for determining an amount of change in the one parameter relative to a unit amount of change in the another parameter in at least one of the standard gaits, as the parameter sensitivity of the selected gait and for storing the parameter sensitivity in memory;

and generates the approximated gait by using the stored parameter sensitivity.

6. A system according to claim 1, wherein said gait generating means includes:

e. describing means for describing a relationship of perturbation of one of the parameters relative to the parameter relating to the floor reaction force in the standard gaits;

and corrects the approximated gait based on the described relationship of perturbation to generate gaits which satisfy the demand for gait in such a manner that at least one of the displacements and velocities in the generated gaits is continuous at a boundary of the gaits.

7. A system according to claim 6, wherein the perturbation of one of the parameters is a perturbation of a horizontal body position.

8. A system according to claim 6, wherein the relationship is described by a linear model.

9. A system according to claim 8, wherein the relationship is described by an inverted pendulum model.

10. A system according to claim 6, wherein the relationship is described by time-series tabulated data.

11. A system according to claim 1, wherein said gait generating means generates the approximated gait by excluding the parameter relating to the floor reaction force if the parameter relating to the floor reaction force is under a predetermined condition.

12. A system according to claim 1, wherein said gait generating means includes;

f. joint angle command calculating means for calculating a joint angle command of the robot based on the generated gait; and

g. joint controlling means for controlling the joint of the robot such that it traces the calculated joint angle command.

13. A system according to claim 12, wherein said joint angle command calculating means includes;

h. detecting means for detecting a state of the robot; and

i. correcting means for correcting a position and an orientation of the robot in response to the detected state;

and calculates the joint angle command such that the corrected position and the orientation are effected.

14. A system according to claim 5, wherein said gait generating means includes;

describing means for describing a relationship of perturbation of one of the parameters relative to the parameter relating to the floor reaction force in the standard gaits;

and corrects the approximated gait based on the described relationship of perturbation to generate gaits which satisfy the demand for gait in such a manner that at least one of the displacements and velocities in the generated gaits are continuous at a boundary of the gaits.

15. A system according to claim 14, wherein the perturbation of one of the parameters is a perturbation of a horizontal body position.

16. A system according to claim 14, wherein the relationship is described by a linear model.

17. A system according to claim 16, wherein the relationship is described by an inverted pendulum model.

18. A system according to claim 14, wherein the relationship is described by time-series tabulated data.

19. A system according to claim 5, wherein said gait generating means generates the approximated gait by excluding the parameter relating to the floor reaction force if the parameter relating to the floor reaction force is under a predetermined condition.

20. A system according to claim 6, wherein said gait generating means generates the approximated gait by excluding the parameter relating to the floor reaction force if the parameter relating to the floor reaction force is under a predetermined condition.

21. A system according to claim 5, wherein said gait generating means includes;

joint angle command calculating means for calculating a joint angle command of the robot based on the generated gait; and

joint controlling means for controlling the joint of the robot such that it traces the calculated joint angle command.

22. A system according to claim 6, wherein said gait generating means includes;

joint angle command calculating means for calculating a joint angle command of the robot based on the generated gait; and

joint controlling means for controlling the joint of the robot such that it traces the calculated joint angle command.

23. A system according to claim 21, wherein said joint angle command calculating means includes;

detecting means for detecting a state of the robot; and

correcting means for correcting a position and an orientation of the robot in response to the detected state; and

calculates the joint angle command such that the corrected position and the orientation are effected.

24. A system according to claim 22, wherein said joint angle command calculating means includes;

detecting means for detecting a state of the robot;

correcting means for correcting a position and an orientation of the robot in response to the detected state; and

calculates the joint angle command such that the corrected position and the orientation are effected.

25. A system for generating a gait of a legged mobile robot having at least a body and a plurality of leg links each connected to the body through a joint, comprising:

standard gait storing means for storing, in memory, a plurality of standard gaits, including at least a gait to start walking, a gait for constant speed walking, and a gait to stop walking, each comprising a set of parameters including a parameter relating to motion of the robot;

gait demanding means for making a demand for gait; and

gait generating means for generating an approximated gait which satisfies the demand for gait by selecting one or a plurality of the standard gaits in response to the demand for gait, and by conducting approximation on at least one of the parameters of the selected standard gait or gaits.

26. A system according to claim 25, wherein said gait generating means generates the approximated gait by calculating a weighted average of at least one of the parameters of the selected gaits.

27. A system according to claim 25, wherein said gait generating means generates the approximated gait by using a parameter sensitivity of one of the parameters to another of the parameters of the selected gait or gaits.

28. A system according to claim 25, wherein said gait generating means generates the approximated gait by calculating a weighted average of at least one of the parameters of the selected gaits and by using a parameter sensitivity of one of the parameters to another of the parameters of the selected gait or gaits.

29. A system according to claim 27, wherein said gait generating means includes:

change amount determining means for determining an amount of change in the one parameter relative to a unit amount of change in the other parameter in at least one of the standard gaits, as the parameter sensitivity of the selected gait and for storing the parameter sensitivity in memory;

and generates the approximated gait by using the stored parameter sensitivity.

30. A system according to claim 25, wherein said gait generating means includes:

joint angle command calculating means for calculating a joint angle command of the robot based on the generated gait; and

joint controlling means for controlling the joint of the robot such that it traces the calculated joint angle command.

31. A system according to claim 30, wherein said joint angle command

calculating means includes:

detecting means for detecting a state of the robot; and

correcting means for correcting a position and an orientation of the robot in response to the detected state;

and calculates the joint angle command such that the corrected position and the orientation are effected.