Sliding mode hybrid impedance control of robot manipulators interacting with unknown environments using VSMRC method

In the present paper, the objective of hybrid impedance control is specified and a robust hybrid impedance control approach is proposed. Based on the concept of hybrid control, the task space is decomposed into position and force controlled subspaces. Impedance control is used in the position controlled subspace. Desired inertia and damping are applied in the force controlled subspace to meliorate the dynamic behavior of robot manipulator. Robust controller using the variable structure model reaching control (VSMRC) is introduced that can realize the objective impedance in the sliding mode in finite time. In order to overcome the chattering effect due to sliding mode approach, fuzzy logic methodology is employed in the control system. In addition, the reaching transient response is undertaken with prescribed quality. Simulating the control system for a 6DOF PUMA560 robot confirms the validity and effectiveness of the proposed control system.