Impedance matching for a serial link manipulator

We propose a new index for dynamic performance analysis of serial link manipulators named impedance matching ellipsoid, or IME. Several indexes have been proposed for indicating static and dynamic performance of robot manipulators. For example, dynamic manipulability ellipsoid (DME) characterizes distributions of hand acceleration produced by normalized joint torque. manipulating-force ellipsoid (MFE) denotes static torque-force transmission efficiency from actuators at joints to a hand. On the other hand, the proposed IME characterizes dynamic torque-force transmission efficiency from actuators at joints to a load held at the hand of the manipulator. The IME includes a wide range of concepts proposed so far as measures of manipulator's performance. The DME and the MFE are both derived from the IME as limiting forms about the load mass. In this paper, we demonstrate the IME with some numerical examples including the selection of an optimal leg posture for jump robots, optimum active stiffness control, and an extension for manipulators mounted on satellites in outer space.