Robust Digital Position Control of a DC Servo System

Description

This project involved the design, simulation, and implementation of a robust digital controller for a DC servo motor. The aim was to meet strict performance requirements — including fast response, minimal overshoot, zero steady-state error, and reliable operation under plant variations such as added mass or braking.

The work was divided into two key phases: system identification and controller design. System modelling was carried out using experimental step, ramp, and sinusoidal inputs to characterise the motor's dynamics. Based on this, a cascaded controller structure was developed, with an inner loop for velocity control and an outer PI loop for position control.

The controller was tuned and validated through both simulation and laboratory experiments, showing excellent tracking, disturbance rejection within one second, and robustness to parameter variations. The project demonstrated practical application of classical and digital control theory in real-world engineering contexts.