Disturbance Attenuation Control of A Class of Unceractuated Systems with Acceleration Measurement

In this paper, a new kind of disturbance attenuation controller design method, based on the acceleration measurement, is proposed for a class of underactuated systems by combining with the backstepping and H_infin technique. Comparing with the traditional high gain acceleration feedback control method, where the acceleration feedback loop is important but difficult to design, the acceleration measurement in the new controller is only used to obtain the disturbance signals. Simultaneously, in order to overcome the heavy noise accompanied with the acceleration measurement and the algebraic loop problem, a linear pre-filter is introduced. The designing process concerns both nonlinear H_infin controller and linear filter theory, which make the disturbance be attenuated from the concepts of both linear filter in frequency domain and input-output finite gain L₂ stability in time domain. In the end, simulations are conducted with respect to the tracking control of unmanned model helicopter. The results are compared with those obtained by the tracking control without acceleration measurement to verify the feasibility of it.