Research And Application Of Control Of Several Kinds Of Nonlinear Systems

Compared with the nonlinear strict feedback system,the nonlinear pure feedback system is a more general system,which can reflect the situation of actual things more,and has received extensive attention and become a hot research object.For a class of nonlinear pure feedback systems,because of the existence of non-affine structures,the conventional coordinate transformation methods are no longer applicable.From this point of view,the article proposes a non-traditional coordinate transformation from another perspective.Based on the non-traditional coordinate transformation studied the following:1.Controller design problem for a class of nonlinear pure feedback systems is studied.By introducing a first-order auxiliary system to handle the diversity of control inputs,combined with the non-traditional coordinate transformation,the controller is introduced.Through the simulation example analysis,this kind of pure feedback system not only makes the state globally bounded,but also the tracking error is asymptotic.It tends to be stable,and is more advantageous than the method provided by the recently published article.2.Design of a predetermined performance controller for a class of nonlinear pure feedback systems is studied.In order to make the pure feedback system have predetermined performance,the paper proposes two functions and new states about time to form a Lyapunov-type with root number and logarithm.Using the unconventional coordinate transformation and the introduced controller,combined with simulation examples,it can be seen that the global pure feedback system is globally bounded and the tracking error is between the two set functions and is asymptotically stable.It can also be known that the nonlinear pure feedback system has predetermined performance.3.Adaptive controller design problem for a class of uncertain pure feedback systems is studied.In order to deal with unknown parameters,the article sets a function about time to estimate the error of the parameters;using non-traditional coordinate transformation and adaptive control methods,the controller is designed.Simulation results show that the designed controller can make the system globally bounded and the tracking error is stable;the adaptive law estimation follows the parameters;and finally it is applied to the Buck converter.Compared with the related literature,the trackingerror and the estimated effect are more precise.illustrates the effectiveness and superiority of the algorithm.4.Problem of output regulation of a class of nonlinear pure feedback systems is studied.The article designs an internal model to suppress external nuisance,and then uses a non-traditional coordinate transformation method to push out the controller.Combined with theoretical and simulation examples,it can be seen that the control law can make the system globally asymptotically bounded and track the tracking signal generated by the external system under the condition of suppressing external interference.5.Spacecraft attitude and disturbance suppression controller design problems are studied.By designing the nonlinear internal model to estimate the unknown nonlinear external system,using adaptive theory to process the uncertain parameters,and combining the stability analysis method of Lyapunov function,an adaptive law and controller are designed.Through simulation,it is verified that the control algorithm can make the aircraft In the case of suppressing interference,the global state of the aircraft model can also be made stable,and the designed internal model can estimate the unknown nonlinear external system.