Variable structure control law design for helicopter based on output feedback

In this paper, a sliding mode control law for helicopter is presented. The control law is based on the newly developed sliding mode control theory which is called sliding mode output feedback control (SMOFC). The iterative linear matrix inequality (ILMI) method is used to solve a set of bilinear matrix inequalities (BLMI) which are introduced by SMOFC. As for the model of helicopter, the linear perturbation model is employed for designing procedure and a reference model is used to guarantee the dynamic responses. The linear control law, which has been working for many years, is also preserved as the siding mode. Thus the system will perform similarly to the original system after the practical system settles in the sliding mode surface. The simulation results illustrate the feasibility and efficacy of this method.