Development and evaluation of simulation model for force-free control strategies

Construction and evaluation of the two different strategies of force-free control of industrial type robot arm is presented in this paper. First, robot arm dynamic model for two link model and basic structure of force-free control method are described. Then two different force-free control architectures are illustrated. Two different force-free control strategies are force-free control by dynamic external torque and force-free control by dynamic torque independent compensation, respectively. Analysis of the each type of force-free control strategy is carried out for the single link and two links perspectives of industrial robot arm configurations by means of simulations under Matlab/Simulink environment. The model characteristics of the force-free control are exploited to discuss the application scenarios. Moreover, analysis of the force-free control is carried out by using real robot parameters throughout the simulations. Since the force-free control deals with external forces applied on the robot arm, it can be used to illustrate the interactive force control between a human and a robot arm by passive motion over an external force.