Nonlinear uncertain systems with nonlinear control channel and unilateral input constraints

ABSTRACT

In this paper, we study the constraints of control inputs, which is important to system performance, but rarely noticed. To deal with the constraints in practical situations, a new approach is proposed based on using diffeomorphism, which is the first introduced. Based on this transformation, the control input can be regarded as a function of an auxiliary variable. As a result, the value of control input is limited to a prescribed bound by choosing the proper bounded function. That is, it provides a new aspect to deal with the inequality control input constraints. The range of the input bounds is related to the uncertainties and can be designed according to the actual situation. This novel control is proven to guarantee uniform boundedness and uniform ultimate boundedness. In the simulation, we show this control renders a superior performance at a lower control cost, comparing with the LQR control.

KEYWORDS:

• Nonlinear systems
• uncertainty
• input constraint
• boundary control
• time-varying disturbance

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported in part by the Fundamental Research Funds for the Central Universities, CHD under Grant (Nos. 300102250507 and 300102258305), in part by the Natural Science Foundation of Anhui Province under Grant (No. 1908085QE194), and in part by the Fundamental Research Funds for the Central Universities of China, HFUT, under Grant (No. JZ2019HGTA0042).