Impedance Matching for Serial Link Manipulators

Abstract

In this paper, we propose a new index of manipulator's dynamic capability named Impedance Matching Ellipsoid, or IME, for serial link manipulators. Several indexes have been proposed in the past to illustrate statically and dynamically capability of a robot manipulator. For example, Dynamic Manipulability Ellipsoid (DME) describes a distribution of hand acceleration produced by normalized joint torque. Manipulating-Force Ellipsoid (MFE) denotes static force transmission from joints to a hand. On the other hand, the proposed IME illustrates dynamic torque-force transmission efficiency from actuators at joints to an object held at a hand. The concept of the IME involves a wide range of proposed indexes proposed as measures of manipulator's capability. The DME and MFE are both derived as a typical representation of the IME. This paper demonstrates the IME with numerical examples including optimal leg posture for a jump robot, optimum active stiffness control, and an extension to a free-flying manipulator.