Gait pattern generating device for legged mobile robot

• US 20040044440A1
• Filed: 05/16/2003
• Published: 03/04/2004
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Takenaka, Toru
• Granted Patent: US 6,876,903 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• 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

A gait generation system of a legged mobile robot, in particular a biped robot that has the dynamic model expressing the relationship between the motion of the body and leg and the floor reaction force, and provisionally determines the current time gait parameters including at least parameters that determine leg trajectory and the like in response to a demand, supposes the parameters of a periodic gait, corrects the current time gait parameters such that the body trajectory determined from the dynamic model and the parameters of the current time gait, etc., converges to a body trajectory determined from the parameters of the periodic gait, and determines instantaneous values of the current time gait based on the corrected current time gait parameter. With this, the system can generates a gait of any stride, turning angle and walking period, including the floor reaction force acting on the legged mobile robot, that satisfies the dynamic equilibrium condition. Further, the system can generates a gait in such a manner that the displacement and velocity of each robot part are continues at the boundary of the generated gait and that succeeding thereto, can generate a gait that is high in the margin of stability, can predict future behavior of the robot and generate a gait such that no disadvantages such as posture divergence occurs.

Claims

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

a. a dynamic model that expresses relationship between motion of the leg and the body, and a floor reaction force;

b. current time gait parameter provisionally-determining means for provisionally determining parameters of a current time gait including at least parameters determining a trajectory of the leg and a trajectory of the floor reaction force, in response to at least a demand;

c. periodic gait parameter supposing means for supposing the parameters of a periodic gait succeeding to the current time gait in response to at least the demand;

d. current time gait parameter correcting means for correcting at least the provisionally determined parameters of the current time gait such that the trajectory of the body determined based on the dynamic model and the parameters of the current time gait and the periodic gait succeeding thereto substantially converges or becomes equal to a trajectory of the body of the periodic gait determined from the parameters of the periodic gait; and

e. current time gait instantaneous value determining means for determining instantaneous values of the current time gait based on at least the corrected parameters of the current time gait.

3. A system according to claim 1 or 2, wherein a transitional gait is inserted between the current time gait and the periodic gait succeeding thereto.

4. A system according to claim 3, wherein the transitional gait includes a standstill gait.

9. A system according to any of claims 1 to 5 and 8, wherein the floor reaction force includes at least a ZMP.

10. A system according to any of claims 1 to 9, wherein the inverted pendulum is a linear model.

2. A system for generating a gait of a legged mobile robot having at least a body and a plurality of legs each connected to the body, comprising:

a. a dynamic model that expresses relationship between motion of the leg and the body, and a floor reaction force;

b. current time gait parameter provisionally-determining means for provisionally determining parameters of a current time gait including at least parameters determining a trajectory of the leg and a trajectory of the floor reaction force, in response to at least a demand;

c. periodic gait parameter supposing means for supposing the parameters of a periodic gait succeeding to the current time gait in response to at least the demand;

d. periodic gait boundary divergent component determining means for determining a periodic gait boundary divergent component that is a value indicating a divergent component at gait boundary when behavior of the body of the periodic gait is approximated by the dynamic model, based on the parameters of the periodic gait;

e. current time gait parameter correcting means for correcting the parameters of the current gait such that the divergent component becomes equal to or becomes substantially equal to each other at terminal of the current gait generated with use of the dynamic model; and

f. current time gait instantaneous value determining means for determining instantaneous values of the current time gait based on at least the corrected parameters of the current time gait.

5. A system for generating a gait of a legged mobile robot having at least a body and a plurality of legs each connected to the body, comprising:

a. leg reaction force calculating means for calculating a leg reaction force that is a resultant force of inertial force and gravity induced by a motion of the leg, without depending on behavior of the body;

b. inverted pendulum model supporting point position calculating means for calculating a position of a supporting point of an inverted pendulum that describes dynamic behavior of the body, from at least the calculated leg reaction force and a desired floor reaction force;

c. inverted pendulum displacement calculating means for calculating displacement of the inverted pendulum based on at least the calculated position of the supporting point of the inverted pendulum;

d. body position calculating means for calculating a position of the body based on at least the calculated displacement of the inverted pendulum; and

e. gait generating means for generating a gait based on at least the calculated position of the body.

6. A system for generating a gait of a legged mobile robot having at least a body and a plurality of legs each connected to the body, comprising:

a. leg ZMP calculating means for calculating a leg ZMP that is corresponding to a ZMP of the leg that is a pseudo value of a resultant force of inertial force and gravity induced by a motion of the leg, without depending on behavior of the body;

b. inverted pendulum model supporting point position calculating means for calculating a position of a supporting point of an inverted pendulum that describes dynamic behavior of the body, from at least the calculated ZMP and a desired ZMP;

c. inverted pendulum displacement calculating means for calculating displacement of the inverted pendulum based on at least the calculated position of the supporting point of the inverted pendulum;

d. body position calculating means for calculating a position of the body based on at least the calculated displacement of the inverted pendulum; and

e. gait generating means for generating a gait based on at least the calculated position of the body.

7. A system according to claim 6, wherein the inverting pendulum model supporting point calculating means calculates the supporting point of the inverted pendulum by subtracting a product obtained by multiplying the leg ZMP by a second coefficient from a product obtained by multiplying the desired ZMP by a first coefficient.

8. A system for generating a gait of a legged mobile robot having at least a body and a plurality of legs each connected to the body, comprising:

a. a dynamic model having;

a leg reaction force calculating means for calculating a leg reaction force that is a resultant force of inertial force and gravity induced by a motion of the leg, without depending on behavior of the body;

inverted pendulum model supporting point position calculating means for calculating a position of a supporting point of an inverted pendulum that describes dynamic behavior of the body, from at least the calculated leg reaction force and a desired floor reaction force;

inverted pendulum displacement calculating means for calculating displacement of the inverted pendulum based on at least the calculated position of the supporting point of the inverted pendulum; and

body position calculating means for calculating a position of the body based on at least the calculated displacement of the inverted pendulum;

b. current time gait parameter provisionally-determining means for provisionally determining parameters of a current time gait including at least parameters determining a trajectory of the leg and a trajectory of the floor reaction force, in response to at least a demand;

c. periodic gait parameter supposing means for supposing the parameters of a periodic gait succeeding to the current time gait in response to at least the demand;

d. periodic gait boundary divergent component determining means for determining a periodic gait boundary divergent component that is a value indicating a divergent component at gait boundary when behavior of the body of the periodic gait is approximated by the dynamic model, based on the parameters of the periodic gait;

e. current time gait parameter correcting means for correcting the parameters of the current gait such that the divergent component becomes equal to or becomes substantially equal to each other at terminal of the current gait generated with use of the dynamic model; and

f. current time gait instantaneous value determining means for determining instantaneous values of the current time gait based on at least the corrected parameters of the current time gait.