Hybrid motion control of humanoid robot for leader-follower cooperative tasks

Abstract

This paper presents a framework for leader-follower type cooperative transportation of an object by multiple humanoid robots or a single robot and a human. The emphasis in this paper is on the hybrid control algorithm and motion generation of the follower robot, while the influence of the leader has been simulated as external force acting on the follower's hands. The presented approach uses impedance controller to provide compliant behaviour of robot arms and it is an extension of our previous work on dual-mode impedance controller for safe humanrobot interaction. Synthesis of the follower's legs and trunk motion is based on the reconfigurable adaptive motion primitives, which are defined as simple, parameterized motion building blocks that can be combined in a sequence or in parallel to generate complex motion. It has been already proven that motion generation, based on reconfigurable adaptive primitives enables the robot to modify gait parameters online, at any time instant, and synthesize dynamically balanced walk. Motion of the follower is based on the reactive approach, where the gait parameters (walking velocity, direction and step length) depend on intensity and direction of the external force vector. Robot end-effectors are compliant in horizontal plain, adapting to the physical guidance of the leader, while being stiff in vertical direction in order to compensate the external force in negative z-direction. The proposed framework has been tested by numerical simulations involving a dynamic robot model.

Torque control of a wheeled humanoid robot with dual redundant arms

“…A compliance control algorithm adopted for a kinesthetic teaching of a humanoid robot TORO (TOrque-controlled humanoid RObot) using hidden Markov model for recording data was illustrated by Ott et al 8 External forces and disturbances were integrated into the controller. A balancing control and a velocity control developed for a wheeled humanoid robot used in clustered environment were given by Nagarajan et al 9 A sliding mode control scheme adopted for a humanoid upper-body robot to control manipulation tasks was carried out by Savić et al 10 Uncertainties and external disturbance were considered during the controller design. A nonlinear controller strategy combining a feedback PD controller and a feed-forward controller were developed by Amin et al 11 for a humanoid robot to imitate human-like motions.…”