Gravity compensation for an ilpmsm driver based on a robust uncertainty controller with system delay compensation

Gravity compensation for an ironless linear permanent magnet synchronous motor (ILPMSM) driver based on a robust uncertainty controller with system delay compensation is presented. In the proposed control scheme, the robust uncertainty controller includes an inverse of the designed first order reference model with an input deduction and integral term; the system delay compensation adopts an inverse system delay model to compensate the system transport delay effect. The proposed controller can reduce disturbance and modeling uncertainty due to the difference between the reference model and the real system model, and the proposed controller does not require knowing precise system parameters. The system response that can be achieved is similar to that of the designed reference model, where DC gain is one. Therefore, DC gain of the controlled closed-loop system is denoted as one, so the proposed controller does not need to be combined with other control algorithms. In this paper, first, the proposed control scheme is used for ILPMSM system current control to reduce disturbance due to the d-q axis coupling effect and modeling uncertainty. Next, it is used for ILPMSM system velocity control to reduce modeling uncertainty and disturbances of friction and gravity force. The effectiveness of the proposed control scheme is verified by the simulation and experimental results.