GAIT CREATION DEVICE OF LEG-TYPE MOBILE ROBOT

• US 20090312867A1
• Filed: 10/31/2006
• Published: 12/17/2009
• Est. Priority Date: 12/12/2005
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Ohno, Nobuyuki, Hasegawa, Tadaaki
• Granted Patent: US 8,204,625 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 provisional desired motion trajectory of an object is determined based on a moving plan of the object. Then, it is determined whether a robot leg motion can satisfy a necessary requirement. The requirement is related to a position/posture relationship between the object and the robot, and a determination of whether the requirement can be satisfied is made at a future, predetermined step. A restrictive condition related to robot leg motion is satisfied at each step up to the predetermined number of steps. If the requirement is satisfied, then a desired gait is generated on the basis of the provisional desired motion trajectory. Otherwise, a desired gait is generated on the basis of a desired motion trajectory of the object according to a corrected moving plan.

Claims

1. A gait creation device of a leg-type mobile robot for generating a desired gait to make a leg-type mobile robot, which is equipped with a plurality of legs extended from a body thereof, perform an operation of moving an object, comprising:

a future object motion provisionally determining means which determines a first provisional desired motion trajectory of the object in a future predetermined period, which includes a period of a plurality of steps of the robot, based on at least a moving plan for the object when generating a desired gait anew for the robot to follow; and

a determining means which determines whether a motion of a leg of the robot that satisfies a necessary requirement is possible for the object, which moves according to the determined first provisional desired motion trajectory, based on at least the first provisional desired motion trajectory and the necessary requirement, the necessary requirement being such that a predetermined requirement related to a position/posture relationship between the object and the robot when the object is moved is satisfied at least at a step of a predetermined number of steps of two or more of the robot in a future and a predetermined restrictive condition related to the motion of the leg of the robot is satisfied at each step up to the step of the predetermined number of steps,

wherein, when a determination result of the determining means is affirmative, the desired gait of the robot is generated such that the necessary requirement is satisfied with respect to the object, which moves according to the first provisional desired motion trajectory, or when the determination result of the determining means is negative, the moving plan is corrected, a second provisional desired motion trajectory of the object in the predetermined period is determined anew based on at least the corrected moving plan, and the desired gait of the robot is generated such that the necessary requirement is satisfied with respect to the object, which moves according to the second provisional desired motion trajectory.

2. The gait creation device of a leg-type mobile robot according to claim 1,

wherein the predetermined requirement includes a requirement that defines a position/posture relationship between a landing position/posture of a leg on a free leg side of the robot and the position/posture of the object, and the predetermined restrictive condition includes a restrictive condition that defines relative landing position/posture of the leg on the free leg side of the robot with respect to a leg on a supporting leg side, and

the determining means comprises a means which determines first provisional predicted landing position/posture of the leg on the free leg side of the robot up to the step of the predetermined number of steps based on the determined first provisional desired motion trajectory of the object and the predetermined requirement such that the requirement is satisfied at each step up to the step of the predetermined number of steps, a means which determines second provisional predicted landing position/posture obtained by restricting the first provisional predicted landing position/posture at each step up to the step of the predetermined number of steps by the predetermined restrictive condition, and a means which determines whether the first provisional predicted landing position/posture and the second provisional predicted landing position/posture at the step of the predetermined number of steps agree or substantially agree with each other and in a case of disagreement, this means correcting the second provisional predicted landing position/posture at least at one step before the step of the predetermined number of steps based on a difference between the first provisional predicted landing position/posture and the second provisional predicted landing position/posture at the step of the predetermined number of steps within a range in which the predetermined restrictive condition is satisfied, and the gait creation device determines whether the motion of the leg of the robot that satisfies the necessary requirement is possible by determining whether the second provisional predicted landing position/posture at the step of the predetermined number of steps can be corrected to the position/posture that agree or substantially agree with the first provisional predicted landing position/posture at the step of the predetermined number of steps within the range, in which the predetermined restrictive condition is satisfied, by the correction at least at the one step.

3. The gait creation device of a leg-type mobile robot according to claim 2, comprising a means which determines anew the predicted landing position/posture of the leg on a free leg side at the step of each number of steps up to the step of the predetermined number of steps such that the landing position/posture of the leg on the free leg side at least one step before the step of the predetermined number of steps are different from the first provisional predicted landing position/posture and that the necessary requirement is satisfied when the determination result of the determining means is affirmative and the first provisional predicted landing position/posture and the second provisional predicted landing position/posture at the step of the predetermined number of steps do not agree or substantially agree with each other, wherein the desired gait of the robot is generated based on the predicted landing position/posture of the leg on the free leg side up to the newly determined step of the predetermined number of steps.

4. The gait creation device of a leg-type mobile robot according to claim 2, comprising:

a means that determines, when a determination result of the determining means is negative, third provisional predicted landing position/posture of the leg on the free leg side of the robot up to the step of the predetermined number of steps so as to bring the predicted landing position/posture of the leg on the free leg side of the robot at the step of the predetermined number of steps close to the first provisional predicted landing position/posture at the step of the predetermined number of steps within the range in which the predetermined restrictive condition is satisfied;

a means which estimates a first predicted moving path of the object that satisfies the predetermined requirement with respect to the determined third provisional predicted landing position/posture;

a means which estimates a second predicted moving path of the object that satisfies the predetermined requirement with respect to the first provisional predicted landing position/posture; and

a means which corrects a velocity command value of the object in the moving plan based on a movement distance of the object in a first predetermined period when it is assumed that the object is moved according to the first predicted moving path, the time of the first predetermined period, a movement distance of the object in a second predetermined period when it is assumed that the object is moved according to the second predicted moving path, and the time of the second predetermined period.

5. The gait creation device of a leg-type mobile robot according to claim 4, wherein the means for correcting the velocity command value of the object in the moving plan uses the movement distance of the object in the first predetermined period in a case, where it is assumed that the object is moved along a path obtained by projecting the first predicted moving path in the direction of the second predicted moving path, in place of the movement distance of the object in the first predetermined period when the direction of the first predicted moving path does not agree with the direction of the second predicted moving path.

6. The gait creation device of a leg-type mobile robot according to claim 3, comprising:

a means that determines, when a determination result of the determining means is negative, third provisional predicted landing position/posture of the leg on the free leg side of the robot up to the step of the predetermined number of steps so as to bring the predicted landing position/posture of the leg on the free leg side of the robot at the step of the predetermined number of steps close to the first provisional predicted landing position/posture at the step of the predetermined number of steps within the range in which the predetermined restrictive condition is satisfied;

a means which estimates a first predicted moving path of the object that satisfies the predetermined requirement with respect to the determined third provisional predicted landing position/posture;

a means which estimates a second predicted moving path of the object that satisfies the predetermined requirement with respect to the first provisional predicted landing position/posture; and

a means which corrects a velocity command value of the object in the moving plan based on a movement distance of the object in a first predetermined period when it is assumed that the object is moved according to the first predicted moving path, the time of the first predetermined period, a movement distance of the object in a second predetermined period when it is assumed that the object is moved according to the second predicted moving path, and the time of the second predetermined period.

7. The gait creation device of a leg-type mobile robot according to claim 6, wherein the means for correcting the velocity command value of the object in the moving plan uses the movement distance of the object in the first predetermined period in a case, where it is assumed that the object is moved along a path obtained by projecting the first predicted moving path in the direction of the second predicted moving path, in place of the movement distance of the object in the first predetermined period when the direction of the first predicted moving path does not agree with the direction of the second predicted moving path.