Research On Adaptive Sliding Mode Control Of Uncertain Descriptor Time-delay Systems Based On Observe

The control problem of singular delayed systems has been one of the research hotspots in the control field and fruitful research results have been achieved till now.In addition,taking the robustness to the uncertainties which satisfy the matched conditions into consideration,extensive attention has been increasingly attracted on sliding mode control(SMC)strategy.In most practical situations,state variables are often not easily obtained directly.By incorporating the SMC and state estimation,observer-based SMC or sliding mode observer(SMO)has been presented to achieve the effect of suppressing parametric uncertainties and ensuring stable operation of the system.Based on the previous research and results,this paper is further focused on the problem of the adaptive SMC of the uncertain singular time-delay systems based upon the state estimation,and it is expected to be some complement and improvement for the synthesis problem of singular time-delay systems.The details are provided as follows:1.The adaptive control problem for a class of singular time-delay systems with parameter uncertainty is studied based on SMO technology.Firstly,the unmeasured state variables are generated by a particular observer.In view of linear matrix inequality(LMI)technique,a new admissibility criteria is deduced.Then a switching controller with adaptive rules is synthesized.Finally,an illustrative example is proposed to demonstrate the feasibility of the theoretical method.2.A state-estimation-based adaptive SMC scheme is put forward for a type of uncertain singular systems subject to state delay and input nonlinearity.First,the unmeasured state variables are reconstructed by a modified observer without any inputs,from which a novel linear switching surface is provided.Subsequently,in view of LMI,a new admissibility criteria is deduced.Moreover,a novel adaptive SMC law is synthesized to ensure the established switching surface can be attained in finite moment.At last,two illustrative examples are proposed to demonstrate the feasibility of the control method.3.For the uncertain singular time-delay systems model in research content 2,an observer design subjected to unknown time-delay is deeply studied,and a new linear sliding surface is designed.A new admissibility criterion is obtained.In addition,an associated adaptive control signal is synthesized to ensure that the established switching surface can be attained in finite moment.Finally,three numerical simulations are conducted to confirm the validity and superiority of the specified method.