Modulation of dynamic behavior of anthropomorphic robot: A biomimetic approach with force redundancy

Abstract

The biomimetic approach to robotics is an attempt to apply solutions created by the evolution of biological systems to technical systems. We investigate the feedforward modulation methodology of the dynamic behavior of an anthropomorphic manipulator, which inherently possess abundant actuators. In this work, we explain that for complete modulation of the dynamic behavior of such a system, redundant actuation is essential. Redundant actuation enables the system to modulate the stiffness or weighted stiffness properties such as motion frequency, and even modulates the damping ratio of the system. Thus, the modulation capability of the stiffness property plays an important role. We also address the need for the incorporation of active damper for complete modulation of the dynamic behavior. An illustrative example of a biomimetic, 2-degrees of freedom manipulator resembling the musculoskeletal structure of the human upper-extremity and driven by six actuators, is given. The modulation capability of motion frequencies and damping ratios is verified through a virtual trajectory planning that represents a point-to-point motion accomplished by the progressive movement of the equilibrium posture. To show the effectiveness of the proposed algorithms, several simulation results are illustrated. (C) 2010 Elsevier Ltd. All rights reserved.