PI-funnel control for two mass systems
We model a two mass system as a functional differential equation so that it encompasses friction and hysteretic effects. The structural properties, such as bounded zero dynamics, are investigated. We then propose three simple controllers (separately and in conjunction): a funnel controller, a PI-controller and a high-pass filter. As opposed to previous control strategies of two mass systems which invoke identification mechanisms or neural networks, the controllers in the present paper are based on structural properties of the system only. Despite the simplicity of the controllers, prespecified output behaviour with prespecified accuracy is guaranteed by the funnel controller, active damping of the shaft oscillation by the high-pass filter, zero tracking output error in the steady state by the PI-controller and bounded input disturbances are rejected. Finally, the controllers are implemented on a real plant, an electrical drive.