Impedance control for human-robot interaction with an adaptive fuzzy approach

In order to guarantee the safety of the human-robot interaction, an impedance control with adaptive fuzzy approach is proposed in this paper. First, by introducing a coordinate transformation, the control objective to track a desired impedance model is converted to the convergence of an error signal. Then a filter is used to set up the relationship between the error signal and the control input of the robot dynamics. By doing this, a control law is obtained with fuzzy logic systems to approximate unknown nonlinear dynamical functions, and adaptive laws are designed to guarantee the stability of the closed-loop system. The control law is concise in structure and clear in design process, by which the impedance error will converge to an arbitrarily small neighborhood of origin. Simulation studies are conducted to verify the validity of the proposed approach.