Multimodel H∞ Loop shaping control of a DC motor under variable loads

The multimodel and multicontrol approaches are two powerful techniques which are often useful in literature, to the analyse, the modeling and the control of complex systems. Indeed, the operating range of the process is partitioned into a set of operating regions. For each operation region a local model or/and controller is applied. The effective control applied to the process is a fusion of all these local control laws. In this paper, a multimodel H_∞ Loop shaping controller (MM-HILSC) is designed and applied to a variably loaded DC motor. In order to use the system in variable load applications such as robot actuators, a multi-model controller is designed based on the H_∞ Loop shaping controllers (HILSC). Simulation results show a notable improvement relatively to the classical HILSC. The design controller is simplified by considering a reduced model obtained by decomposition of the global system into two time-scales singularly perturbed model of the DC motor.