控制力矩陀螺框架伺服系统期望补偿自适应鲁棒控制

本文针对控制力矩陀螺框架伺服系统中存在的参数不确定性、摩擦非线性及外部干扰问题,提出了一种考虑LuGre摩擦的自适应鲁棒控制方法.针对陀螺框架伺服系统未知惯量和阻尼系数、LuGre摩擦参数不确定性及未知外部干扰上界,设计参数更新律对其进行估计.在此基础上,为提高系统对不确定参数及未知干扰的鲁棒性,设计带有期望补偿的自适应鲁棒控制器,可实现对LuGre摩擦非线性的精确补偿,同时减小测量信号噪声及外部干扰对系统的不利影响.应用Lyapunov稳定性理论分析了闭环系统的稳定性.对挠性航天器姿态机动控制的仿真结果,验证了所提方法的有效性.     

无人机全电式自主刹车系统滑模极值搜索控制

常规主动刹车系统采用在线辨识跑道特征的算法,但仍需依赖摩擦模型先验知识,难以应对复杂跑道工况.为克服上述问题,提出一种滑模极值搜索控制策略并应用于无人机全电式自主刹车系统.考虑电动作动机构非线性特性,建立系统的状态空间模型并合理简化为严格反馈形式,采用超扭曲算法估计结合系数的梯度,结合反馈线性化控制律得到刹车压力参考值,证明此控制作用下可实现对未知最优滑移率的渐近跟踪.采用反演控制的思想设计无抖振滑模控制器实现对参考刹车压力的跟踪.利用Lyapunov方法获得系统的渐近稳定性条件并分析控制参数对系统的影响.半实物仿真试验结果表明控制策略的有效性.     

带有摩擦非线性的CMG框架伺服系统 有限时间自适应鲁棒控制

针对控制力矩陀螺框架伺服系统中存在的摩擦非线性及不确定性等问题,提出一种基于终端滑模的有限时间自适应鲁棒控制律,确保闭环控制系统跟踪误差能够在有限时间内快速收敛到包含原点在内的任意小邻域内.通过对不确定参数的在线估计提高系统对参数变化的鲁棒性,并抑制外部干扰及摩擦非线性带来的不利影响.采用Lyapunov稳定性理论对闭环控制系统的稳定性进行分析并证明.通过对陀螺框架伺服控制系统进行仿真来验证所提出的控制律的有效性.     

考虑非线性因素的飞机防滑刹车系统控制

飞机的刹车过程存在较强的非线性,目前广泛应用的速度差加压力偏调式(PBM)控制律难以实现对飞机刹车的高性能控制.本文提出了一种考虑飞机刹车过程中非线性因素的滑模控制律.首先建立考虑轮胎跑道非线性和刹车盘摩擦系数非线性的的飞机防滑刹车系统非线性模型,然后设计了滑模观测器对飞机速度进行估计,并在此基础上设计了一种滑模变结构控制律,最后基于模糊理论对滑模控制律进行优化,从而抑制控制器的抖振.仿真结果表明,基于模糊指数趋近律的滑模变结构控制律控制效果优于传统“PD+PBM”控制律,抑制控制器输出抖振效果良好,能够很好的适应刹车过程中的复杂非线性因素,刹车效率高,控制方法合理有效.     

液压混合动力履带车辆联合制动模糊控制

针对液压混合动力履带车辆联合制动系统,为了实现制动过程平稳性,提出了基于制动力分配原则的模糊控制策略.首先在MATLAB中建立了能量再生制动系统和机械制动系统以及车辆动力学仿真模型,然后设计了以制动力分配系数为控制变量的联合制动模糊控制器,给出了模糊控制规则,建立了控制系统仿真模型,并在不同制动强度条件下对车辆制动过程进行仿真.仿真结果表明,联合制动模糊控制系统能够有效回收制动能量,同时与PID控制相比明显改善和提高了履带车辆制动过程稳定性.     

模糊复合控制律对飞机防滑刹车系统性能的改进

针对采用传统控制律的飞机防滑刹车系统鲁棒性差、机轮易在低速段出现严重打滑甚至脱胎现象等缺点，提出了一种新型控制律——模糊复合控制律；并在matlab6．5／simulink环境下，对采用这两种控制律的飞机防滑刹车系统分别进行了仿真研究；将两种情况下的结合系数和滑移率仿真曲线在同一坐标系下给出，结合曲线对两种情况下的刹车系统性能进行了比较分析，结果表明；采用模糊复合控制律的刹车系统鲁棒性增强，刹车效率提高，明显克服了因采用传统控制律而引起的诸多缺点。     

Supervisory control of air–fuel ratio in spark ignition engines

The problem of air–fuel ratio stabilization in spark ignition engines is addressed in this paper. The proposed strategy consists of proper switching among two control laws to improve quality of the closed-loop system. The first control law is based on an a priori off-line identified engine model and ensures robust and reliable stabilization of the system at large, while the second control law is adaptive, it provides on-line adaptive adjustment to the current fluctuations and improves accuracy of the closed-loop system. The supervisor realizes a switching rule between these control laws providing better performance of regulation. Results of implementation on two vehicles are reported and discussed.     

Stabilization of ODE with hyperbolic equation actuator subject to boundary control matched disturbance

ABSTRACT

In this paper, we consider stabilisation for a cascade of ODE and first-order hyperbolic equation with external disturbance flowing to the control end. The active disturbance rejection control (ADRC) and sliding mode control (SMC) approaches are adopted in investigation. By ADRC approach, the disturbance is estimated through a disturbance estimator with both time-varying high gain and constant high gain, and the disturbance is canceled online in the feedback loop. It is shown that the resulting closed-loop system with time-varying high gain is asymptotically stable and is practically stable with constant high gain. By SMC approach, the existence and uniqueness of the solution for the closed loop via SMC are proved, and the monotonicity of the ‘reaching condition’ is presented. The resulting closed-loop system is shown to be exponentially stable. The numerical experiments are carried out to illustrate effectiveness of the proposed control law.     

On improvement of transient performance in tracking control for a class of nonlinear systems with input saturation

This paper studies the technique of the composite nonlinear feedback (CNF) control for a class of cascade nonlinear systems with input saturation. The objective of this paper is to improve the transient performance of the closed-loop system by designing a CNF control law such that the output of the system tracks a step input rapidly with small overshoot and at the same time maintains the stability of the whole cascade system. The CNF control law consists of a linear feedback control law and a nonlinear feedback control law. The linear feedback law is designed to yield a closed-loop system with a small damping ratio for a quick response, while the nonlinear feedback law is used to increase the damping ratio of the closed-loop system when the system output approaches the target reference to reduce the overshoot. The result has been successfully demonstrated by numerical and application examples including a flight control system for a fighter aircraft.     

Estimation of road frictional force and wheel slip for effective antilock braking system (ABS) control

The introduction of electric braking via brake‐by‐wire systems in electric vehicles) has reduced the high transportation delays usually involved in conventional friction braking systems. This has facilitated the design of more efficient and advanced control schemes for antilock braking systems (ABSs). However, accurate estimation of the tire‐road friction coefficient, which cannot be measured directly, is required. This paper presents a review of existing estimation methods, focusing on sliding‐mode techniques, followed by the development of a novel friction estimation technique, which is used to design an efficient ABS control system. This is a novel slip‐based estimation method, which accommodates the coupling between the vehicle dynamics, wheel dynamics, and suspension dynamics in a cascaded structure. A higher‐order sliding‐mode observer–based scheme is designed, considering the nonlinear relationship between friction and slip. A first‐order sliding‐mode observer is also designed based on a purely linear relationship. A key feature of the proposed estimation schemes is the inclusion of road slope and the effective radius of the tire as an estimated state. These parameters impact significantly on the accuracy of slip and friction estimation. The performance of the proposed estimation schemes are validated and benchmarked against a Kalman filter (KF) by a series of simulation tests. It is demonstrated that the sliding‐mode observer paradigm is an important tool in developing the next generation ABS systems for electric vehicles.     

一类不确定脉冲型混杂系统的保代价控制

针对混合代价函数,研究了参数不确定脉冲型混杂系统的保代价控制问题,给出了混杂状态反馈保代价控制律的设计方法,由此得到的控制律既能使系统闭环鲁棒渐近稳定,又可使系统的闭环混合代价指标在对象参数摄动的范围内不超过确定的上界.本文提出的控制律不仅包含连续时间动态,也包含离散事件动态,而且其离散事件动态行为不需要与被控系统的离散事件动态行为一致,因此设计时不要求被控系统的每个连续时间子系统都具有可控性.仿真结果表明所提设计方法是可行有效的.     

Constrained robust model predictive control via parameter-dependent dynamic output feedback

This paper considers output feedback robust model predictive control for the quasi-linear parameter varying (quasi-LPV) system with bounded disturbance. The so-called quasi-LPV means that the varying parameters of the linear system are known at the current time, but unknown in the future. The control law is parameterized as a parameter-dependent dynamic output feedback, and the closed-loop stability is specified by the notion of quadratic boundedness. An iterative algorithm is proposed for the on-line synthesis of the control law via convex optimization. A numerical example is given to illustrate the effectiveness of the controller.     

Robust explicit model predictive control via regular piecewise-affine approximation

This paper proposes an explicit model predictive control design approach for regulation of linear time-invariant systems subject to both state and control constraints, in the presence of additive disturbances. The proposed control law is implemented as a piecewise-affine function defined on a regular simplicial partition, and has two main positive features. First, the regularity of the simplicial partition allows one to efficiently implement the control law on digital circuits, thus achieving extremely fast computation times. Moreover, the asymptotic stability (or the convergence to a set including the origin) of the closed-loop system can be enforced a priori, rather than checked a posteriori via Lyapunov analysis.     

考虑摩擦力影响精密伺服系统的鲁棒自适应控制

针对具有摩擦力扰动的精密伺服系统提出了一种鲁棒自适应控制方法.首先,对基于 bristle模型的动态摩擦力模型进行了线性参数化,该线性参数化过程包含了对stribeck效应的 线性参数化处理;然后,基于构造的Lyapunov函数设计全局渐近稳定自适应控制律,并对闭环 系统的跟踪性能进行了严格的理论分析.仿真实验验证了算法的有效性.     

伺服系统摩擦的支持向量回归建模与反步控制

研究了一种伺服系统摩擦建模和控制的新方法.首先,根据实验数据,提出了基于支持向量机回归的自适应库仑摩擦和固定库仑摩擦建模方法,以解决在速度为零时摩擦力矩不连续导致的建模不准确问题.然后应用所建立的摩擦模型,使用反步法设计了控制器从而实现了摩擦的自适应补偿.通过使用Lyapunov理论证明了闭环系统的稳定性.仿真结果验证了该方法的有效性.     

考虑LuGre 摩擦的伺服系统自适应模糊控制

针对摩擦非线性的存在会使伺服系统控制精度难以提高的问题,建立了考虑动态LuGre摩擦的伺服系统数学模型,在系统参数和负载转矩未知的情况下设计了自适应模糊控制器,用自适应模糊逻辑系统在线逼近包含LuGre摩擦在内的非线性环节,从而实现了伺服系统高精度的位置跟踪。利用Lyapunov函数证明了闭环系统的稳定性。仿真结果表明,该控制器能有效地补偿摩擦非线性的影响,并对负载转矩变化具有较强的鲁棒性。     

线性广义系统的迭代学习控制

针对线性时不变广义系统的迭代学习控制问题．利用时间加权范数性质．通过Frobenius范数给出广义系统在D型和PD型闭环学习律作用下系统的实际输出轨迹逐渐逼近理想输出轨迹的充分条件．并指出在D型闭环学习律的基础上加上P型闭环学习律不影响控制系统的收敛性．但可以改变系统的性能．仿真算例说明了该方法的有效性．     

基于参考模型的扰动观测器控制系统

为了补偿控制系统的未知动态和外部扰动,论文提出一种基于参考模型的扰动观测器控制系统.首先,分析了二阶理想参考模型控制系统的设计,并通过闭环传递函数证明了参考模型控制系统的稳定性.然后,设计了二阶系统扰动观测器和基于参考模型的扰动观测器控制律,分析了二阶闭环控制误差系统收敛性.并推广到n阶控制系统,证明了n阶闭环控制误差系统稳定性.最后,仿真实验结果表明,与线性自抗扰控制(LADRC)系统相比,基于参考模型的扰动观测器控制系统阶跃响应的跟踪精度和抗扰性能明显优于LADRC系统,扰动的估计精度高,控制输入量小于LADRC系统;基于参考模型的扰动观测器控制系统正弦跟踪精度和扰动的估计精度也高于LADRC系统.该新型控制系统结构简单,抗扰性能好,控制效率高,具有重要的工程应用价值.     

城市轨道车辆电力牵引实验台测控系统设计

介绍了一种城市轨道车辆电力牵引实验台,针对其多参数采集和实时控制的特点,设计了基于虚拟仪器的测控系统。系统以工业计算机为核心,采用LabVIEW语言编程,对牵引电机进行转速闭环控制,并采集转速量,实时计算相应的车辆运行速度和路段,从而使负载电机进行动态阻力加载。系统实验结果与实车测试数据的对比分析显示,该测控系统使牵引电机的启动阶段加速度保持1.03 m/s2,在电制动过程中,当直流母线电压达到设定阀值670 V时,再生制动向电阻制动实时切换,工作特性与实车测试数据基本一致。系统对于城市轨道车辆牵引和电制动特性方面的研究具有重要意义。