Abstract: With regards to robot grinding and polishing, it is significant to control the contact force between the end tool and the workpiece surface as expected value, especially in the dynamic process of robot surface tracking. Aiming at the problem that the normal contact force is not stable, which is caused by the past force signal is difficult to compensate for the future contour changes, a compliance control method based on force feedback and priori inclination of contour is proposed. Firstly, the robot surface tracking contact model based on the impedance control equation is established to describe the position/force relationship between the end tool and the workpiece surface. Secondly, the mapping relationship between controlling velocity of normal direction and the feedback force is constructed. Thirdly, the priori normal velocity, which is calculated by the priori inclination of contour, is combined with a designed online trajectory generator and applied to correct the controlling velocity of normal direction. The experimental results show that, both of concave and convex surface of the workpiece, the method with priori velocity correction can decrease the vibration of the contact force effectively. Furthermore, compared with the method without priori velocity correction, the force variance of the proposed method is reduced by more than 55%.

Key words: surface tracking, compliant control, priori inclination of contour, controlling velocity of normal direction