Impedance Control of a Flexible Link Robot for Constrained and Unconstrained Maneuvers Using Sliding Mode Control (SMC) Method

In this paper, the modeling and impedance-control of a one link flexible robot is presented. the concept of impedance control of flexible link robots is rather new and is being addressed for the first time. the control algorithm is valid for both constrained and unconstrained maneuvers. first, equations of motion and the associated boundary conditions are derived using hamilton's principle. a linear finite dimensional model is, then, generated in the cartesian coordinates, using the assumed mode method and by introduction of a proper coordinate transformation. the target impedance is, then, introduced in the cartesian coordinate system and a control law is designed to realize the proposed target impedance for a given frequency range, using the sliding mode control theory. a set of computer simulations are carried out to demonstrate the effectiveness of the proposed control law. simulations are carried out with various contact stiffness. as the results show, when the environmental surface stiffness is smaller than, or comparable to, that of the link, the control system is able to achieve stable behavior and the link vibration diminishes rather rapidly. however, when the environmental stiffness is much greater than that of the stiffness of the link, although the robot achieves stable behavior during contact, the vibrations tend to increase.