Gait generator of legged mobile robot

• US 7,734,377 B2
• Filed: 07/28/2005
• Issued: 06/08/2010
• Est. Priority Date: 10/15/2004
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Hasegawa, Tadaaki
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): KING, RODNEY P
• Application Number:
  US11/576,656
• Publication Number:
  US 20080133055A1
• Time in Patent Office: 1,776 Days
• Field of Search: 700/245, 700/252, 700/54, 901/1, 901/47
• US Class Current: 700/252
• 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 generator determines a desired motional trajectory and a desired object reaction force trajectory of an object 120 for a predetermined period after the current time by using an object dynamic model while supplying, to the object dynamic model, a model manipulated variable (estimated disturbance force) for bringing a behavior of the object 120 on the object dynamic model close to an actual behavior, and provisionally generates a gait of a robot 1 for a predetermined period by using the aforesaid determined trajectories. Based on the gait and an object desired motion trajectory, a geometric restrictive condition, such as interference between the robot 1 and the object 120, is checked, and a moving plan for the object 120 or a gait parameter (predicted landing position/posture or the like) of the robot 1 is corrected as appropriate according to a result of the check, so as to generate a gait of the robot 1. Thus, a desired gait that satisfies a predetermined geometric restrictive condition related to the interference between the robot 1 and an object is generated by reflecting an actual environmental condition in real time while carrying out the operational control of the robot 1.

Claims

1. A gait generator of a legged mobile robot for generating a desired gait for causing the legged mobile robot equipped with a plurality of leg bodies extended from its body to perform an operation for moving an external object while actuating the robot such that the desired gait is followed, the gait generator comprising:

an object dynamic model representing a relationship between forces acting on an object and motions of the object;

a model manipulated variable determining means for determining a model manipulated variable to be imparted to the object dynamic model in order to bring a behavior of the object on the object dynamic model close to a behavior of the actual object while observing the behavior of the actual object when actuating the robot such that the desired gait is followed;

a between-robot-and-object action force trajectory provisionally determining means for provisionally determining, on the basis of at least a moving plan of the object and a motion state amount of the object on the object dynamic model, the trajectory of a desired action force between the robot and the object, which is a desired trajectory of an action force between the object and the robot in a predetermined period after the present time such that the motion state amount follows the motion state amount of the object based on the moving plan while imparting the determined model manipulated variable to the object dynamic model when generating a new desired gait to be followed by the robot;

an object motion trajectory provisionally determining means for provisionally determining a desired motion trajectory of the object in the predetermined period by using the object dynamic model by inputting the provisionally determined trajectory of the desired action force between the robot and the object to the object dynamic model while imparting the determined model manipulated variable to the object dynamic model;

a robot gait provisionally generating means for provisionally determining a gait parameter to be used to generate a desired gait of the robot on the basis of at least the provisionally determined desired motion trajectory of the object and the provisionally determined trajectory of the desired action force between the robot and the object, and for provisionally generating a desired gait of the robot in the predetermined period by using the provisionally determined gait parameter;

a restrictive condition determining means for determining whether a predetermined geometric restrictive condition related to at least one of the object and the robot is satisfied on the basis of the provisionally determined desired motion trajectory of the object and a motion trajectory of the provisionally generated desired gait of the robot; and

a correcting means for selecting at least one of the moving plan, the provisionally determined gait parameter, and the provisionally determined desired motion trajectory of the object as a correction target and for correcting the correction target so as to satisfy the geometric restrictive condition if the geometric restrictive condition is not satisfied,

wherein the new desired gait is generated by using the correction target that has been corrected.

2. The gait generator of a legged mobile robot according to claim 1, wherein the model manipulated variable determining means is a means for estimating, as the model manipulated variable, a disturbance force other than a force acting on an object from the robot out of a force acting on an actual object.

4. The gait generator of a legged mobile robot according to claim 1, wherein the gait parameter to be corrected by the correcting means includes a predicted landing position of a leg body of the robot.

5. The gait generator of a legged mobile robot according to claim 2, wherein the gait parameter to be corrected by the correcting means includes a predicted landing position of a leg body of the robot.

3. A gait generator for generating a desired gait for causing the legged mobile robot equipped with a plurality of leg bodies extended from its body to perform an operation for moving an external object while actuating the robot such that the desired gait is followed, the gait generator comprising:

an object dynamic model representing a relationship between motions of the object and forces acting on the object;

a disturbance force estimating means for estimating a disturbance force, other than a force acting on the object from the robot, of a force acting on an actual object while observing a behavior of the actual object when actuating the robot such that the desired gait is followed;

a motion state amount provisionally determining means for provisionally determining a desired motion state amount that defines a desired motion trajectory of the object in a predetermined period after the present time on the basis of at least the moving plan of the object when generating a new desired gait to be followed by the robot;

an object action force trajectory provisionally determining means for provisionally determining an object action force desired trajectory, which is a desired trajectory of a force to be applied to the object in the predetermined period after the present time, by inputting the provisionally determined desired motion state amount to the object dynamic model and by using the object dynamic model;

a between-robot-and-object action force trajectory provisionally determining means for provisionally determining the trajectory of a desired action force between the robot and the object, which is a desired trajectory of an action force between the object and the robot in the predetermined period on the basis of the provisionally determined object action force desired trajectory and the estimated disturbance force;

a robot gait provisionally generating means for provisionally determining a gait parameter to be used to generate a desired gait of the robot on the basis of at least a desired motion trajectory of the object defined by the provisionally determined desired motion state amount and the provisionally determined trajectory of the desired action force between the robot and the object, and for provisionally generating a desired gait of the robot in the predetermined period by using the provisionally determined gait parameter, the estimated disturbance force, and the provisionally determined desired action force between the robot and the object;

a restrictive condition determining means for determining whether a predetermined geometric restrictive condition related to at least one of the object and the robot is satisfied on the basis of the desired motion trajectory of the object defined by the provisionally determined desired motion state amount and a motion trajectory of the provisionally generated desired gait of the robot; and

a correcting means for selecting at least one of the moving plan, the provisionally determined gait parameter, and the desired motion trajectory of the object that is defined by the provisionally determined desired motion state amount as a correction target and for correcting the correction target so as to satisfy the geometric restrictive condition if the geometric restrictive condition is not satisfied,

wherein the new desired gait is generated by using the correction target that has been corrected.