Method for gait generation and tracking control for a bipedal walking robot
First Claim
1. A method for controlling a legged robot with torque-controlled or position controlled joints, comprising:
- determining a foot hold location on a support surface for a foot of the legged robot;
generating a set of joint trajectories for joints of the legged robot to achieve the foot hold location;
computing desired torques to provide the set of joint trajectories; and
generating actuator commands to operate actuators on the legged robot to provide the desired torques to move the foot of the legged robot to the foot hold location,wherein the determining of the foot hold location includes performing nonlinear optimization with forward simulation using the state of the legged robot as a first input and a mathematical model of the legged robot providing constraints for the nonlinear optimization as a second input.
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Abstract
A control method that executes a numerical non-linear optimization procedure with forward simulation of the full dynamics of the bipedal robot (including ground collisions) to compute a foothold, which produces the desired center of mass velocity during the next step of the walking cycle. The controller includes a gait generator that outputs desired joint trajectories designed to track a desired foothold provided by the foot placement algorithm. A torque calculator is included to output desired joint torques designed to track the desired joint trajectories provided by the gait generator. Additionally, the controller includes an actuator controller that produces the desired joint torques determined by the torque calculator at each joint on the physical robot, which may be a legged robot with torque-controlled joints. The foot placement algorithm may use nonlinear optimization that is solvable using a mathematical model of the dynamics of the controlled robot.
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Citations
23 Claims
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1. A method for controlling a legged robot with torque-controlled or position controlled joints, comprising:
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determining a foot hold location on a support surface for a foot of the legged robot; generating a set of joint trajectories for joints of the legged robot to achieve the foot hold location; computing desired torques to provide the set of joint trajectories; and generating actuator commands to operate actuators on the legged robot to provide the desired torques to move the foot of the legged robot to the foot hold location, wherein the determining of the foot hold location includes performing nonlinear optimization with forward simulation using the state of the legged robot as a first input and a mathematical model of the legged robot providing constraints for the nonlinear optimization as a second input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A robot controller for providing actuator control signals to motors or actuators used to drive joints or linkages of a legged robot during walking on a surface, comprising:
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a foot placement algorithm module generating a foot-hold location on the surface for a foot of the legged robot, wherein the foot-hold location is generated by processing a state of the legged robot and a set of dynamic constraints of the legged robot; a gait generation algorithm module generating a desired state of the legged robot based on the foot-hold location and the state of the legged robot; and a torque control module generating commands to the motors or actuators of the legged robot to achieve the desired state of the legged robot including positioning the foot at the foot-hold location on the surface. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method for controlling a bipedal robot, comprising:
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with a processor running a foot placement algorithm, determining a foot hold location for the biped robot based on a sensed present state of the bipedal robot and on a mathematic model of the biped robot including torque limits and joint limits; with the processor running a gait generator, generating a desired movement for the bipedal robot to move a foot of the bipedal robot to the foot hold location; with a torque calculator module run by the processor, determining desired torques for joints of the bipedal robot to achieve the desired movement of the bipedal robot; and generating actuator commands to operate actuators on the bipedal robot to provide the desired torques on the bipedal robot. - View Dependent Claims (20, 21, 22, 23)
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Specification