Adaptive impedance control of the industrial robot

Summary form only given. The paper presents a strategy for controlling an industrial manipulator to comply with the environment and to exert the desired forces at the end-effector. The impedance control strategy is utilized ensuring a mass-spring-damper behavior of the robot end-effector. Since the industrial robots are commonly position controlled and because usually there is no access to direct actuator current control, the position-based impedance control approach is employed. This class of impedance controllers consists of inner/outer loop configuration. The inner loop presents the position servo supplied by the robot manufacturer, while the outer loop uses force feedback signal modifying the inputs to the position servo and at the same time satisfying the impedance dynamic equation. Within the controller presented, the commanded trajectory delivered to the position servo is generated by an impedance filter and additional adaptive controller. To overcome the problem of lack of information about the environment, MRAC is used.