Open flexible PD-controller design for different filtering properties

The paper represents first part of two contributions dealing with simplified modular design of filtered PD (FPD) and disturbance observer (DO) based filtered PID control (FPID) illustrated by example of positional servo control. This first part is devoted to analysis of the FPD controller tuned for different types of nonmodelled or filter dynamics. Openness of the approach means that different order filters required for implementation of these controllers and noise attenuation may be introduced without necessity to repeat in the nominal case analysis of the optimal and critical tuning. By simpler means, flexible approach enabling to fit filtering requirements of particular loop is proposed. Achieved performance is evaluated by newly introduced measures for deviations from monotonic and two-pulse shapes of transients typical for control of plants with dominant 2nd order dynamics.