Dynamic surface control for a class of nonlinear systems. (English) Zbl 0991.93041
Summary: A new method is proposed for designing controllers with arbitrarily small tracking error for uncertain, mismatched nonlinear systems in the strict feedback form. This method is another “synthetic input technique”, similar to backstepping and multiple surface control methods, but with an important addition, $r-1$ low pass filters are included in the design, where $r$ is the relative degree of the output to be controlled. It is shown that these low pass filters allow a design where the model is not differentiated, thus ending the complexity arising due to the “explosion of terms” that has made other methods difficult to implement in practice. The backstepping approach, while suffering from the problem of “explosion of terms” guarantees boundedness of tracking errors globally; however, the proposed approach, while being simpler to implement, can only guarantee boundedness of tracking errors semiglobally when the nonlinearities in the system are non-Lipschitz.
|93C10||Nonlinear control systems|