A Kinematic Control Framework for Asymmetric Semi-autonomous Teleoperation Systems

Abstract

<p>This thesis presents a unified framework for coordination and control of human-in-the-loop asymmetric semi-autonomous robotic systems. It introduces a highly general teleoperation system configuration involving any number of operators, haptic interfaces, and robots with possibly different degrees of mobility. The proposed framework allows for mixed teleoperation/autonomous control of user-defined subtasks by establishing position/force tracking as well as kinematic constraints among relevant <em>teleoperation control frames</em>. Three layers of velocity-based autonomous subtasks at different priority levels with respect to human teleoperation are integrated into the control system design. The control strategy is hierarchical comprising of a high-level teleoperation coordinating controller and low-level joint velocity controllers. A Lyapunov-based adaptive joint-space velocity controller is presented as one candidate for the low-level control. The approach utilizes idempotent, generalized pseudoinverse and weighting matrices, as well as a soft-switching rank changing algorithm in order to achieve new performance objectives that are defined for such asymmetric semi-autonomous teleoperation systems. A detailed analysis of system performance and stability is presented. The proposed framework constitutes the most general formulation and solution for the teleoperation control problem to date. It yields many interesting and useful system configurations never studied before, in addition to those already considered in the literature. In particular, seven system configurations arising from the proposed teleoperation architecture are analyzed and studied in detail. Experimental results are provided to demonstrate the desired system response in these configurations. Moreover, human factors experiments are carried out to assess operator(s) performance in maneuverability and grasping under various teleoperation system configurations. The results show statistically significant performance improvement in teleoperation of a nonholonomic mobile robot and telegrasping using a twin-armed manipulator.</p>