Delay-dependent H_(2)/H_(∞) Control for Vehicle Magneto-rheological Semi-active Suspension

The exist researches of the magneto-rheological semi-active suspension(MSAS) control mainly focus on the design of control laws,which aim at obtaining an optimal control strategy to improve the ride comfort and handling stability.In the controller design,the stability of the MSAS system cannot be confirmed owing to the control input time delay considered little.In this paper,a quarter vehicle MSAS model with time-delay is built.Therefore,through formulating the sprung mass acceleration suitably as the optimization object,suspension deflection and tyre dynamic load and coulomb damping force as the constraint objects,with considering the control input time-delay,a delay-dependent state feedback H2/H∞ controller is designed.According to Lyapunov-Krasovskii functional theory,the sufficient conditions for asymptotic stability and the existence of delay-dependent H2/H∞ controller are obtained,and the controller design is transformed into the minimization problem for linear function through linear matrix inequality(LMI).Random road excitation simulations and experiments are carried out.The simulation and experiment results show that the design can preserve the closed-loop stability and achieve the performances for MSAS system in spite of the existence of the control input time-delay.The present study can provide an important basis and method for research on time-delay problem in MSAS and other chassis subsystems.

Mixed H_2/H_∞ State Feedback Attitude Control of Microsatellite Based on Extended LMI Method

For the appearance of the additive perturbation of controller gain when the controller parameter has minute adjustment at the initial running stage of system,to avoid the adverse effects,this paper investigates the mixed H_2/H_∞ state feedback attitude control problem of microsatellite based on extended LMI method.Firstly,the microsatellite attitude control system is established and transformed into corresponding state space form.Then,without the equivalence restriction of the two Lyapunov variables of H_2 and H∞performance,this paper introduces additional variables to design the mixed H_2/H_∞ control method based on LMI which can also reduce the conservatives.Finally,numerical simulations are analyzed to show that the proposed method can make the satellite stable within 20 s whether there is additive perturbation of the controller gain or not.The comparative analysis of the simulation results between extended LMI method and traditional LMI method also demonstrates the effectiveness and feasibility of the proposed method in this paper.

Three-dimensional nonlinear H_2/H_∞ guidance law based upon approach of solving the state feedback Nash balance point

Based upon the theory of the nonlinear quadric two-person nonzero-sum differential game,the fact that the time-limited mixed H2/H∞ control problem can be turned into the problem of solving the state feedback Nash balance point is mentioned. Upon this,a theorem about the solution of the state feedback control is given,the Lyapunov stabilization of the nonlinear system under this control is proved,too. At the same time,this solution is used to design the nonlinear H2/H∞ guidance law of the relative motion between the missile and the target in three-dimensional(3D) space. By solving two coupled Hamilton-Jacobi partial differential inequalities(HJPDI),a control with more robust stabilities and more robust performances is obtained. With different H∞ performance indexes,the correlative weighting factors of the control are analytically designed. At last,simulations under different robust performance indexes and under different initial conditions and under the cases of intercepting different maneuvering targets are carried out. All results indicate that the designed law is valid.

一类非线性微分代数系统的L_2-增益分析及状态反馈H_∞控制

分析了一类非线性微分 代数系统的 L2 增益 ,并讨论了一类状态反馈H∞ 控制问题 .在一定条件下给出了控制器的设计 ,并保证了闭环指数为 1且零解渐近稳定 .

Robust Optimal H∞ Control for Uncertain 2-D Discrete State-Delayed Systems Described by the General Model

This paper investigates the problem of robust optimal H∞ control for uncertain two-dimensional (2-D) discrete state-delayed systems described by the general model (GM) with norm-bounded uncertainties. A sufficient condition for the existence of g-suboptimal robust H∞ state feedback controllers is established, based on linear matrix inequality (LMI) approach. Moreover, a convex optimization problem is developed to design a robust optimal state feedback controller which minimizes the H∞ noise attenuation level of the resulting closed-loop system. Finally, two illustrative examples are given to demonstrate the effectiveness of the proposed method.

参数不确定线性系统混合H^2/H~∞状态反馈控制

对一类含有范数有界参数不确定线性系统的混合Ｈ２／Ｈ∞状态反馈控制问题进行了研究． 给出了系统一个输出在满足给定的Ｈ∞干扰衰减约束条件下，其另一个输出的Ｈ２ 性能指标所满足的上界，并利用Ｌａｇｒａｎｇｅ 乘子法导出了使得该界达到最小的“最优的”状态反馈控制器．结果仅需求解一个含有两个尺度参数的修正代数Ｒｉｃｃａｔｉ方程． 而且数值结果表明该方法是非常有效的．

2-D T-S模糊时滞系统状态反馈H∞控制

针对Fornasini-Marchesini(FM)模型描述的具有区间时变时滞的二维(2-D)离散模糊系统,研究延迟依赖稳定性和状态反馈H控制问题。首先,选取包含更多时滞信息的双重及三重求和的Lyapunov-Krasovskii函数(LKF)。其次,利用Wirtinger不等式,得到了一种基于线性矩阵不等式(LMI)的延迟依赖稳定性准则,进而给出了保证所研究系统具有给定H性能的状态反馈控制器的设计方法。最后,考虑热过程的实际算例,通过MATLAB工具箱求得增益矩阵,利用仿真图验证所得定理的正确性。

汽车主动悬架H2/H∞多目标优化控制

为协调主动悬架各项相互冲突的性能,采用基于H2/H∞混合控制进行约束优化,解决半车电液主动悬架系统多目标优化控制问题。选择路面扰动到悬架质量垂直加速度和俯仰角加速的闭环传递函数的H2范数为平顺性指标,路面扰动到悬架动行程、主动控制力和轮胎动位移的闭环传递函数的H∞范数为操纵稳定性指标,选择合理的γ1值,最终求出全状态最优控制律。仿真中假设平整路面上有一个包块,作为路面扰动脉冲输入,将该控制方案与半车被动悬架的时域仿真结果进行对比。结果表明该方案较好地解决了舒适性与操纵稳定性指标之间的矛盾。

具有极点约束的线性振动系统的一种主动控制设计:LMI方法

本文讨论具有闭环极点约束的线性振动系统状态反馈主动控制设计问题。极点约束集是左半复平面上一个由圆形和带状区域构成的凸域 ,以闭环系统的H2 指标为优化目标 ,将该设计问题转化成一个易于计算的线性矩阵不等式 (LMI)约束的凸优化问题求解。最后运用本文方法对一个双层隔振系统模型进行状态反馈控制设计 。