Controller Design and Shaft Torque Vibration Suppression for Servomechanism With Elasticity

This paper proposes a novel controller design method for servomechanism with elasticity to guarantee the position and speed response damping as well as dynamic. The disturbance observer (DOB), offering extra torque shaft feedback, promotes the natural frequency of the speed loop to attain anti-resonant frequency. The speed reference is compensated reasonably in speed loop output, taking the optimal amplitude-frequency response into account. The position loop proportional and feedforward gain are designed to achieve good position response using the polynomial design method. However, a high dynamic response may impose the speed controller saturates, which inevitably induces severe motor speed and shaft torque oscillation. The auxiliary proportional-derivative (PD) controller is proposed to compensate for the dynamic of shaft torque under the controller saturation, which achieves the protection of the drive train. The parameter design method in the proposed controller is simple and distinct. Experimental results validate the effectiveness of the proposed strategy.