Robust proximate time-optimal servomechanism with speed constraint for rapid motion control

• A robust proximate time-optimal controller based on extended state observer for motion systems with practical speed constraint is presented with stability analysis.
• Experiments on a DSP-controlled PMSM servo system demonstrate the near-optimal performance and robustness.
• The parameterized design can be easily applied to other servo motion.

A control scheme is proposed to achieve fast and accurate set-point servo motion in typical double integrator systems subject to disturbances and speed constraint. The controller consists of a Proximate Time-optimal Servomechanism (PTOS) control law and a compensation term for the unknown disturbance. An extended state observer is adopted to estimate the un-measured velocity signal and the unknown disturbance. In the presence of speed constraint, a speed regulation stage is incorporated between the PTOS acceleration and deceleration stages. The closed-loop stability is analyzed theoretically. The control scheme is then applied to the position-velocity control loop in a permanent magnet synchronous motor servo system for set-point tracking. MATLAB simulation has been conducted, followed by experimental verification based on the TMS320F2812 DSP controller board. The results confirm that the proposed control scheme can track a wide range of target references fast and accurately, and has good performance robustness with respect to the disturbance and parameter variations.