New method for compensating uncertainty of control plant

Aim at the issue that vehicle bench test system uncertainty in contradiction with its performance specifications, new method of compensation plant uncertainty is proposed. By analyzing the cause of uncertainty and its bad effect on system performance, according to structure invariance, using feedback control theory and combining with H°° mixed sensitivity, then the so-called Tracking output Signal of Normalized Model (TOSNM) method is produced. The reasons for uncertainty reduction are discussed and its decreasing is quantified. The simulation result shows the proposed method can effectively reduce uncertainty. In the low frequency band, with this method, uncertainty could be reduced to one percent of the original.