Robust adaptive speed control for DC motor using novel weighted E-modified MRAC

Novel Adaptive law modification termed “weighted e-modification” for MRAC is presented in this paper. Speed control of DC motor with mismatched disturbance load torque is considered; totally unknown model parameters and only upper bounded fast load torque are dealt with. The proposed modification approached the advantages of the performance of the non-modified MRAC and the robustness of the e-modified MRAC. The simulations results showed that weighted e-modification technique speed response has better performance than classical e-modification technique and the non-modified MRAC because it gathered the advantage of the two of performance and robustness; control action resulting from weighted e-modification had better performance than e-modification and avoided the robustness failure due to adaptive gains drift of the non-modified MRAC. MRAC adaptive gains drifted up to unbounded limit due to disturbance while uniform boundedness of adaptive gains are achieved by e-modification and weighted e-modification.