Expanded proximate time-optimal servo control for motor position regulation

This paper extends the existing Proximate Time-optimal Servomechanism (PTOS) control methodology to the more typical second-order servo systems with a damping element. A parameterized design of expanded PTOS control law with a speed-dependent linear region is presented for rapid and smooth set-point tracking using a bounded input signal. The control scheme uses the time-optimal bang-bang control law to accomplish maximum acceleration or braking whenever appropriate and then smoothly switches into a linear control law to achieve a bumpless settling. The control scheme is then applied to the position-velocity control loop in a permanent magnet synchronous motor servo system for set-point position regulation. Numerical simulation has been conducted, followed by experimental verification based on a TMS320F2812 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.