A Test Bed to Compare Two Forms of Kinematic Algorithms for Tele-robotic Control Applications

The conventional method of position control of a tele-robot is by rotation and translation of the end-effector point of resolution (EE POR) using an inverse kinematics algorithm. A new method of POR control is proposed at the wrist joint (WR POR). The two inverse kinematics algorithms are implemented in a tele-operated robot system and a systems approach is used to develop the robotic system along with subject-based performance studies and a comparison of the mental workload induced on the operator to study the efficacy of the implementations. The construction of the tele-robotic test bed is detailed with information on the input devices, inverse kinematics algorithms and their integration. The inverse kinematics provides the operator with continuous position control of the POR. Understanding the interaction of these algorithms with humans is critical. User performance while operating the system with these two modes of control is evaluated by obtaining tracking, time and error data during object insertion tasks. Subjective mental workload data was obtained using the NASA-Task Load Index (TLX). The focus of this study is to gain a deeper understanding of the effects of placing the POR at the end-effector or the wrist on the end-user. Metrics for use in tele-operated robots derived from this study are stated. Mental workload was found to be lower with control at the wrist POR along with task completion time. Reversal errors and distance measures did not return very significantly different results.