Analysis and Experimental Verification of a Fourth Order Plant Model for Manipulator Force Control

Abstract

The analysis and experimental verification of a fourth order model of the arm/sensor/environment system plant, to be used in evaluation of force control strategies are presented. Both the undamped and underdamped eases are investigated. Approximations and qualifications, based on the reality of our experimental system, help reduce the solution to just a few dominant terms. Comparing these terms with experimental data of the system undergoing small oscillations yields approximate values for all of the parameters in the model. To justify the obtained values and thereby the approximations used, two measures are taken. First, a simulation of the fourth order model is performed, and compared against experimental data obtained from the CMU DD Arm II system. Second, a stability analysis of several force control schemes acting on the modelled plant is reviewed and compared against experimental tests of the controllers. In both cases, the simulation and analysis match closely with the experimental results, confirming the validity of the plant model.