An expanded proximate time-optimal servo controller design for fast set-point motion

This paper proposes an alternative design of expanded proximate time-optimal servomechanism (PTOS) controller for typical servo systems characterized by an integrator cascaded with a damping block. The control law is parameterized by the damping ratio and natural frequency of the closed-loop poles within a speed-dependent linear region. The control scheme aims to accomplish maximum acceleration or braking whenever appropriate and then smoothly switches into a linear control law to achieve a smooth settling. An extended state observer (ESO) is also included to estimate the speed and disturbance simultaneously for the purpose of feedback and compensation. The control scheme is applied to a permanent magnet DC motor servo system for set-point position regulation. MATLAB simulation is carried out, and then experimental verification is conducted using a TMS320F28335 digital signal controller board. The results confirm that the servo system can track a wide range of target references with superior transient performance and steady-state accuracy.