Noise attenuation motivated controller design. Part I: Speed control

The paper deals with an experimental evaluation of a modular design of the disturbance observer (DO) based filtered PI control with scalable filtering properties (DO-FPI). Based on simple one-parameter tuning methods it compares outcomes of its application to the speed servo control using incremental position sensor towards the alternative solution based on the two-degree-of-freedom (2DOF) PI control. Under the first tuning scenario, noise filters added to the DO and the P-controller paths may take arbitrary order by simultaneously keeping fixed chosen disturbance response dynamics. This enables a simple noise attenuation adjustment and a significant performance improvement both in the setpoint response, as well as in the noise attenuation. Performance improvements towards the 2DOF PI control reaching to double-figures were confirmed also under the second tuning scenario based on keeping an equal noise attenuation corresponding to a constant impact of a torque ripple.