A new method for implementing active stiffness control of robot manipulator by using sliding mode

Active stiffness control is one of the control strategy used for force control. However, such control scheme has a drawback that its controller gain setting is directly proportional to its desired stiffness. This inherently implies that the robustness of system performance will be traded off by the range of desired stiffness. In addition, such control scheme is sensitive to environment stiffness. This paper presents a new approach of implementing active stiffness control using the sliding mode control strategy. By defining a special switching surface and using theory of variable structure control, the desired stiffness is decoupled with the controller gain, and the system is also robust to environment stiffness changing. Simulation results show good potential of these methods