Cooperation of Robots in Manipulation of Unknown Objects with Multiple Impedance Control

Parameter identification techniques are particularly attractive to determine the inertial parameters of robot manipulators and manipulated payloads. These parameters are particularly needed in implementation of a model-based controller for robot manipulators. In this paper, the inertial parameters of a manipulated rigid-body object have been estimated. The Newton-Euler equations will be employed to relate the measured joint forces and torques via acceleration-dependent coefficients to the inertial parameters. These parameters will then be estimated on-line by least square method with 100 data points. The Multiple Impedance Control (MIC) is an advanced model-based algorithm which enforces designed impedance on both a manipulated object, and all cooperating manipulators. The MIC is implemented here on a system of two cooperating Puma560 manipulators. As simulation results show, the response of the MIC algorithm in the occurrence of an impact due to collision with an obstacle is smooth, even with noticeable estimation error in moments of inertia parameters; which emphasizes the robustness of MIC algorithm.