Delay-dependent Non-fragile Robust Static Output Feedback Control And Its Application To Active Suspension

Static output feedback (SOF) controller requires a small amount of onlinecomputational effort due to the simplicity of the structure. Consequently, it can reducethe cost of the controller implementation, but it is difficult to be solved. Therefore, thedesign of SOF controller is one of the most important problems in the control theoryand application. Moreover, as is well-known, model uncertainties and time-delay arecharacteristics that are commonly encountered in various engineering system, such asvehicle active suspension system. On the other hand, a study of a non-fragile controlthat can tolerate some level of controller parameter variations is theoretically andpractically significant. A key point of the vehicle active suspension system design toimprove the ride comfort is control strategy, and its effectiveness in relation to theperformance of active suspension system. Thus, the controller design of the activesuspension system with good performance to improve vehicle ride comfort andhandling stability has a very important significance.The main research topic of this paper is to directly and effectively design adelay-dependent non-fragile robust multi-objective SOF controller for an uncertainsystem with input time-delay, and verify the feasibility and effectiveness of theproposed design approach by application to design an active suspension system.Detailed research contents are as follows:1) In order to design a SOF controller, this paper presents a new PSO-DE/LMIoptimization algorithm that can solve a bilinear matrix inequality (BMI) problemeffectively, and then verifies the feasibility and effectiveness of this algorithm byapplication to design H∞SOF controller and H2SOF controller of the active suspension system.2) In the framework of a multi-objective control, a design approach of themulti-objective SOF controller based on the PSO-DE/LMI algorithm is validatedfurther by H∞/L2-L∞SOF control and H2/L2-L∞SOF control for the active suspensionsystem.3) By employing a Lyapunov-Krasovskii method, new existence conditions ofdelay-dependent robust H∞SOF controller and L2-L∞SOF controller are derivedrespectively in terms of the feasibility of BMIs，and then a delay-dependent H∞/L2-L∞SOF controller is designed by using these existence conditions and the PSO-DE/LMIoptimization algorithm. Moreover, the proposed controller design approach is verifiedby application to active suspension system.4) By considering a controller itself perturbation, this paper presents newexistence conditions of delay-dependent non-fragile robust H∞SOF controller andL2-L∞SOF controller are derived respectively in terms of the feasibility of BMIs，andthen a delay-dependent non-fragile robust H∞/L2-L∞SOF controller is designed byusing these existence conditions and the PSO-DE/LMI optimization algorithm. Inaddition, the feasibility and effectiveness of the obtained controller is validated byapplication to design an active suspension system.This paper validated the practicability and validity of the proposed controlstrategies through the contrastive analysis in frequency domain and time domain withprevious design methods. In addition, aimed at the vehicle active suspension system,further validated the effectiveness of the proposed controller design approach byadopting the joint simulation of the dynamics simulation and analysis software ofmechanical system ADAMS and MATLAB/Simulink.