Iterative feedback tuning of controllers for a two-mass spring system with friction

In this paper, we present a two-degree-of-freedom controller tuning for two-mass spring systems with friction based on the IFT (iterative feedback tuning) approach. While two-mass spring systems are widely used, they sometimes have severe friction. In such a case, the existing IFT methods may not work very well because they heavily rely on the linearity of the plants. In order to cope with such cases, we adopt two strategies. One is the separate tuning of the feedback and feedforward controller. The other is to introduce a quasi-Newton method into a parameter renewal law. The effectiveness of the proposed method is demonstrated through numerical simulations and an experiment