Human motion tracking control with strict contact force constraints for floating-base humanoid robots

摘要

A controller for floating-base humanoid robots that can track motion capture data while maintaining balance. Briefly, the controller includes a proportional-derivative (PD) controller that is adapted to compute the desired acceleration to track a given reference trajectory at every degree-of-freedom (DOF) of the robot including the six unactuated ones of the floating base. Second, the controller includes a component (joint torque optimization module) that computes the optimal joint torques and contact forces to realize the desired accelerations given by the first component (i.e., the PD controller). The joint torque optimization module performs this computation considering the full-body dynamics of the robot and the constraints on contact forces. The desired accelerations may not be feasible for the robot due to limits in normal contact forces and friction (e.g., the robot sometimes cannot exactly copy or perform the modeled human motion defined by motion capture data).

主权项

1. A method for controlling a floating-base robot to track a reference motion, comprising:
sensing the state of the floating-base robot with reference to an operating environment; with a processor, determining desired joint and contact link accelerations based on the reference motion and the state of the floating-base robot; with the processor, computing contact wrenches and joint torques to generate the desired joint and contact link accelerations; with the processor, controlling the floating-base robot to track the reference motion using the contact wrenches and joint torques from the computing step; and repeating the sensing of the state, the determining of desired joint and contact link accelerations, and the computing contact wrenches and joint torques for each control cycle for the floating-base robot.