Control of the 2-degree-of-freedom servo system with iterative feedback tuning

In this article, the controller parameter tuning method of a large inertia 2-degree-of-freedom motion mechanism is presented. The proportional-integral controller is adopted to implement the system control. For the reason of load coupling of the two freedoms, fixed proportional-integral parameters cannot always get satisfied control performance. Based on this problem, the iterative feedback tuning method is applied to tune the controller parameters. This method makes the system output error decrease along the negative gradient direction, and the system cost function will reach local minimum after a few iterations. In order to improve the convergence speed of the iterative process, a gold ratio-based method is proposed to speed up the convergence of the iteration process. The simulation and comparison experiments are performed on the azimuth freedom, and the results show that the iterative feedback tuning method can achieve much higher control performance compared to classical tuning method, and it has the similar effect to the adaptive robust method.