Robust speed control of DC servomotors using fuzzy reasoning

In the speed control of DC servomotors, using an equivalent disturbance torque observer, speed control ability is affected by the estimation error of the equivalent disturbance torque observer. The authors propose a robust speed control scheme for DC servomotors using fuzzy reasoning to consider the estimation error of the torque observer. In order to compensate the estimation error, they combine the equivalent disturbance torque observer and a feedback controller. The influence of the estimation error is restrained by the feedback controller introducing fuzzy reasoning. The reason why they introduce fuzzy control is that the estimation error for the observer has heavy nonlinearity and cannot be detected by a linear error estimator. In this case, it is very convenient to use fuzzy reasoning to identify the estimation error. Simulation and experimental results confirm the validity of the proposed control technique