Research On Control Design Of Uncertain Nonlinear Systems

It is well known that uncertainty and randomness are almost everywhere in the real industrial systems,and nonlinear systems are more accurate and more able to show the essential characteristics of the systems compared with linear systems.Therefore,the control design of nonlinear systems has always been the focus and difficulty in the field of control theory which is widely used in robot systems,power systems,aerospace systems and biochemical systems.Considering the limitations of the actual conditions,it is necessary to realize the asymptotic stability of the systems with the condition of uncertainty.Moreover,compared with asymptotic stability,the finite-time stability of the system has stronger robustness,self-adaptability and anti-interference,and it has extensive practical applications in aerospace,military manufacturing and parts processing and so on.Therefore,the design of asymptotic stability and finite-time stability of nonlinear systems are both theoretical and practical.The main contents of this paper are mainly carried out from the following two aspects:?.Research on global output feedback stabilization of stochastic nonlinear systems based on double gain designThis part mainly investigates the solution of global output feedback stabilization for a class of stochastic nonlinear systems with time-varying measurement error of output.Under linear growth conditions,a new double-domination method is proposed for the first time to construct an output feedback stabilizing controller.Different from the related results,the design of the observer is performed without using the information on the output function and nonlinearities.Another contribution of this section is that a new viewpoint of using feedback stabilization to eliminate the continuous measurement error originating from inaccurate detection of system state is proposed.Finally,an numerical simulation example is presented to demonstrate the effectiveness of control strategy.?.Global fast finite-time adaptive stabilization for high-order uncertain nonlinear systemsThis part studies the problem of global finite-time adaptive stabilization for a class of high-order uncertain nonlinear systems.By developing a fast finite-time stability lemma and extending the idea of continuous domination to adaptive fashion,a state feedback controller with an adaptive mechanism is constructed to globally stabilize the nonlinear systems with fast finite-time convergence.The main novelty of this part is to give an analytic design method in organizing the adaptive fast finite-time stabilizer while providing a less conservative estimation of convergent time.Finally,an numerical simulation example is presented to demonstrate the effectiveness of control strategy.