An obstacle avoidance control scheme for the "Moray arm" on the basis of posture space analysis

Moray arm is a slider-installed manipulator that has large degrees of kinematic redundancy, thus possesses unconventional features such as the ability to enter a narrow space while avoiding obstacles. In this study, an obstacle avoidance control scheme for the Moray arm is proposed, which is based on the 2-DOF Moray drive control method and the posture space analysis. The 2-DOF Moray drive control derogates the control problem of the hyper-redundant degrees of freedom (DOFs) to the simple one of 2 DOFs: one of the control variables signifies the linear combination of the objective initial and final postures of the arm, while another one expresses the amount of the pull-out-displacement when pulling the arm out of the housing slider. The obstacle collision-free trajectory is generated for the Moray arm by analyzing a defined "posture space" that is determined by the above-stated two variables. Simulations are executed to verify the proposed scheme, and show that the scheme works well in the case of the static environment. (C) 2000 Elsevier Science B.V. All rights reserved.