Dynamics Decoupling and Control of a 3-DOF Force-Controlled End-Effector Based on Force Sensors

A 3-DOF force-controlled end-effector based on a parallel mechanism is an effective approach for high-precision polishing in industrial applications. However, the dynamic modeling of rigid-flexible coupling in parallel mechanisms, as well as the decoupled control of friction and coupling forces, remains a challenging task. This paper proposes a dynamic decoupling control method for a 3-DOF force-controlled end-effector. The method utilizes multiple force sensors to acquire joint forces in the end-effector's active joints. It compensates for internal coupling and frictional forces from components such as the branch links and slide rails, thus eliminating the need for a complex dynamic model. The proposed method is validated within a force-position hybrid control framework combined with a decoupling controller. Experimental results demonstrate the significant advantages of this method in terms of transient force response and steady-state force tracking. Moreover, the decoupling method using force sensors has been shown to improve positional accuracy. This approach enhances the end-effector's force control and positional accuracy without requiring a complex dynamic model.