提高车辆安全性的输出反馈自适应控制

研究含有时变参数的车辆动力学模型的输出跟踪控制问题.控制目标是使车辆的横摆角速度和质心侧偏角分别跟踪理想的设定值,通过反推方法设计输出反馈自适应控制器.控制器的输出为主动横摆力矩,通过控制主动横摆力矩来控制车辆的输出响应跟踪理想的输出信号,从而提高车辆的安全性.仿真结果表明,控制器能更好地适应车速和路况的变化,鲁棒性强.

     

一类非线性系统的间接自适应输出反馈模糊控制

针对一类未知非线性系统,提出一种输出反馈控制方法。首先在假设系统状态已知的情况下设计状态反馈控制器,实现跟踪性能。然后在系统状态不完全可测的情况下,通过设计高增益观测器对系统的状态进行估计,实现输出反馈控制器设计。最后证明所设计的输出反馈控制器可获得状态反馈控制器所取得的最大最小问题的跟踪性能。     

一类非线性时滞输出反馈系统的自适应控制

针对一类参数化非线性时滞输出反馈系统,提出了一种无记忆自适应跟踪控制器的设计方案.采用时滞滤波器估计系统状态,用Domination处理非线性时滞项,应用Backstepping技术设计控制器和参数自适应律.放宽了对时滞项的要求.通过构建一个Lyapunov＿Krasoviskii泛函,证明了闭环系统的稳定性,实现了对目标轨线的渐近跟踪,保证了所有信号一致有界.实例仿真说明了该方案的可行性.     

一类具有未知控制方向非线性系统的输出反馈自适应控制

研究了一类控制方向未知非线性系统的输出反馈自适应镇定问题. 首先, 通过一线性状态变换, 将未知控制系数集中起来, 从而将原系统变换为适于控制设计的新系统. 然后, 分别引入状态观测器和参数估计器, 并应用积分反推和调节函数方法, 给出了输出反馈稳定控制律的构造性设计过程. 可以证明,所设计的控制器确保原系统状态渐近收敛到原点, 而其它闭环系统状态有界. 仿真结论验证了所提出方法的有效性.     

一类非线性系统输出反馈自适应扰动抑制

研究了一类依赖于不可量测状态增长非线性系统的输出反馈自适应扰动抑制问题. 与现有文献不同, 所研究的系统具有更多的未知参数, 尤其是不确定控制系数. 为了解决该 问题, 引入了动态高增益K-滤波器, 进而构造了基于K-滤波器的状态观测器. 在输出反馈控制器的设计过程中, 引入了待定设计参数, 增加了设计的自由度. 结果表明, K-滤 波器的动态增益和设计参数的恰当选择可以保证闭环系统的全局稳定性, 从而实现系统 L2-增益意义的扰动抑制.     

一类非线性系统的输出反馈容错控制

针对一类非线性系统,研究了故障情况下基于输出反馈的容错控制问题．首先基于Zhang的自适应观测器和Lin的输出反馈控制律设计了正常系统的标称控制律,分析了该控制律的性能,并得到了故障发生后仍然采用该控制律时闭环系统状态有界的充分条件．在此基础上,设计了故障系统的容错控制律,证明了若发生的故障满足前述的充分条件,则故障系统在该容错控制律下稳定．数值仿真表明了该方法的有效性．     

一类仿射非线性系统的自适应神经网络输出反馈变结构控制

本文研究了一类仿射非线性系统的输出反馈控制问题. 在介绍文献[4~6]的基础上, 提出一种基于神经网络参数化技术的自适应变结构输出反馈控制方案, 该方案能够避免使用严格正实(SPR)条件, 它不仅能够保证收缩条件的可行性, 而且还可以分析闭环系统的稳态和暂态的一致有界性, 并能够对观测增益和控制参数的选取进行清楚地分析.     

齐次非线性系统H∞控制的输出反馈

研究了齐次系统Ｈ∞控制的输出反馈问题,首先给出齐次伫与二次型Ｌｙａｐｕｎｏｖ函数之间的关系,随后讨论了齐次系统Ｈ∞控制的输出反馈总理２,在适当条件下,给出了全局解,然后考虑李具有高阶扰动项的齐次系统,对此系统也得到与无扰动项时的相似结论。     

多变量非线性系统的间接模糊输出反馈自适应控制

针对一类多输入多输出非线性不确定系统，提出一种基于观测器的模糊间接自适应控制方法，并基于李亚普诺夫函数方法，导出了输出反馈控制律以及参数的自适应律，证明了整个控制方案不但能保证闭环系统稳定，而且取得了良好的跟踪控制性能。     

随机非线性严格反馈系统的自适应神经网络输出反馈镇定

针对具有严格反馈形式的随机非线性系统, 首次引入神经网络控制技术, 设计了适当形式的随机控制 Lyapunov函数, 并运用反推(Backstepping)技术和非线性观测器设计技术, 构造出一类自适应神经网络输出反馈控制器. 在一定条件下, 证明了闭环系统平衡点依概率稳定. 仿真算例验证了所给控制方案的有效性.     

Output-feedback control of an underwater vehicle prototype by higher-order sliding modes

This paper describes some experimental results concerning the practical implementation of a recently proposed nonlinear output-feedback control technique based on the higher-order sliding mode approach. The considered technique is applied to the motion control problem for an underwater vehicle prototype that is equipped with a special propulsion system based on hydro-jets with variable-section nozzles. To cope with the heavy uncertainties affecting the prototype dynamics the output-feedback control system has been developed by means of an observer-controller that combines a second-order sliding-mode controller and a second-order sliding-mode differentiator. The reported experiments show that the proposed approach is capable of guaranteeing fast and accurate response under several operating conditions. The control system design procedure, and the main implementation issues, are discussed in detail.     

State observer-based adaptive fuzzy output-feedback control for a class of uncertain nonlinear systems

This paper aims to develop state observer-based adaptive fuzzy control techniques for controlling a class of uncertain nonlinear systems with bounded external disturbances. An adaptive fuzzy observer is proposed to estimate the system state variables. It is shown that the observation errors obtained from the observer are uniformly ultimately bounded. Applying the estimated system state for design of an output-feedback controller, the uniformly ultimate boundedness of the tracking errors for the resulting closed-loop system can be guaranteed. A typical robot arm system is employed in our simulation studies, and the results demonstrate the usefulness and effectiveness of the proposed techniques for controlling nonlinear systems with bounded external disturbances.     

Switching adaptive output-feedback control of nonlinearly parametrized systems

In this paper, we consider global adaptive output-feedback control of nonlinear systems in output-feedback form, with unknown parameters entering nonlinearly. Such unknown parameters are not required to lie in a known compact set. Our proposed adaptive output-feedback controller is a switching-type controller, in which the controller parameter is tuned in a switching manner via a switching logic. Global stability results of the closed-loop system have been proved.     

互联系统的分布输出反馈自适应动态面控制

本文所提方案具有如下特点: 1) 通过使用初始化技术, 给出了互联系统中各个子系统跟踪误差的L1性能指标; 2) 采用动态面控制方法, 避免了反推法带来的“微分爆炸”问题; 3) 通过估计未知参数向量范数, 极大减轻了控制系统的计算负担; 4) 引入了一种高增益观测器, 保证了互联系统中各个子系统跟踪误差可以收敛到任意小, 仿真结果验证了所提方案的有效性.     

Output-feedback control design for NCSs subject to quantization and dropout

In this paper, the output-feedback control problem is considered for networked systems involving in signal quantization and data packet dropout. The states of the controlled system are unavailable and the output signals are quantized before being communicated. An estimation method is introduced to cope with the effect of random packet loss that is modelled as a Bernoulli process. The quantized measurement signals are dealt with by utilizing the sector bound method, in which the quantization error is treated as sector-bounded uncertainty. The output-feedback controller is designed which guarantees the closed-loop system is exponentially mean-square stable. The simulation example is given to illustrate the proposed method.     

两轮自平衡小车模型参考自适应控制平衡算法

两轮自平衡小车是一类非完整的本征不稳定系统,其动力学方程具有复杂非线性、高阶次、强耦合、欠驱动等特点,采用牛顿力学分析法进行系统建模,利用前馈、反馈以及输入量构成自适应机构,在此基础上提出模型参考自适应控制（Model Reference Adaptive Control,MRAC）策略对两轮自平衡小车的姿态和速度进行控制。通过仿真,结果表明采用MRAC算法能够在保证系统稳定的前提下,获得接近于给定理想参考模型的动态性能,并使系统在平衡点附近具有良好的鲁棒性。     

车辆自适应巡航控制策略研究与仿真

为了保证车辆自适应巡航控制(ACC)系统的安全性、跟踪效果和稳定性,基于车辆安全距离模型建立了车辆自适应巡航控制模型,在Trucksim中搭建CACC跟驰控制系统;通过Simulink与Trucksim联合仿真,验证系统的可行性.仿真结果表明,在车辆编队的行驶过程中,前后车的车距始终在设定的安全距离范围内波动,具有良好...     

Output-feedback global tracking for unknown control direction plants with application to extremum-seeking control

This paper addresses the design of a sliding mode tracking controller for single-input–single-output (SISO) uncertain plants with relative degree one and unknown control direction, i.e., with unknown sign of the high frequency gain (HFG). We demonstrate that, for a class of linear plants with nonlinear output function, it is possible to achieve global exact tracking using only output-feedback by combining a recently introduced periodic switching function with a well-known control parameterization of Model Reference Control (MRC). Simulation results are presented to illustrate the good tracking performance. One significant advantage of the new scheme is its robustness to time-varying control direction which is here theoretically justified for jump variations of the HFG and successfully tested by simulation in more general conditions. This property makes it adequate for solving extremum-seeking problems. Theoretical justification is presented for a class of systems with nonlinear output function using only output-feedback. An application to the wheel slip control in Antilock Braking Systems (ABSs) illustrates the practical viability of the proposed control scheme.     

Controller design for vehicle stability enhancement

A Vehicle Dynamics Control (VDC) system is developed for tracking desired vehicle behavior. The cascade structure of control system consists of yaw moment major controller and wheel slip minor controller. The Linear Quadratic Regulator (LQR) theory is exploited for yaw moment controller and the sliding mode theory is applied for wheel slip controller design. The use of yaw moment control was investigated by regulating the wheel slip ratio for improving handling and stability of vehicle. The performance of the control system is evaluated under various emergency maneuvers and road conditions through pure computer simulations and Hardware In-the-Loop Simulation (HILS) system. The results indicate the proposed system can significantly improve vehicle stability for active safety.     

无级变速汽车的自适应模糊控制研究

为提高无级变速汽车控制系统对外界负荷扰动和各种运行工况的自适应能力,本文在简单的无级变速系统模型的基础上,设计了无级变速汽车的自适应模糊控制系统.所设计的自适应模糊控制系统由参数自调节油门模糊控制器和混合型模糊-PID的无级变速器速比和制动控制器构成,该控制系统只与汽车的瞬时运行状态有关而与汽车的参数无关,因此它对不确定的汽车参数和外界负荷的扰动具有良好的鲁棒性.仿真结果表明所设计的模糊控制系统具有良好的自适应能力.