Abstract: The diesel auxiliary power unit (APU) for series HEV is a multiple-input multiple-output complex nonlinear system. For its controller design, a simple identification method for robust control is presented. As the modeling approach for gain scheduling control, the APU is considered as a linear parameter varying system and the model parameters are gridded into a finite set. In each operating point, the system model is identified with the model uncertainty modeling technique, which is expressed as a nominal model and an uncertainty region. Finally, identification tests are performed with the proposed method on the APU bench and experimental results show its validity.

Key words: Robust identification, Auxiliary power unit, Gain-scheduling control, Hybrid electric vehicle, Adhesion coefficient, Slip-dependent friction, Wheel/rail relationship, Creep versus creep-force curve