欠驱动船舶航迹跟踪指令滤波滑模鲁棒控制

为实现欠驱动船舶在模型参数不确定和外界风浪流干扰情况下水平面的航迹跟踪控制,提出了一种指令滤波滑模鲁棒控制方法。利用指令滤波结合反步法建立航迹跟踪误差方程,设计船舶纵向速度和艏摇角的虚拟控制律镇定航迹跟踪误差,并进一步设计船舶艏摇角速度虚拟控制律镇定艏摇角误差;将船舶纵向速度和艏摇角速度的虚拟控制律作为新的跟踪目标,采用积分方法设计基于上下界的滑模控制器,克服了常规反步法对虚拟控制律求导复杂的问题,避免了微分运算在工程应用中难以接受的缺陷和控制输入的抖振现象以及减小稳态误差。仿真实验表明,设计的控制器对欠驱动船舶的模型参数摄动及外界干扰变化不敏感,能够同时实现水平面直线和曲线的精确跟踪。     

不确定欠驱动非线性系统的模糊滑模控制

针对一类不确定欠驱动非线性系统,提出了一种模糊滑模控制新方案．该方案在T-S型模糊控制的基础上引入滑模控制,有效避免了T-S型模糊控制可能出现的不稳定情况,同时改善了系统的动态性能。采用吊车系统进行系统仿真,结果表明了该控制方案的有效性。     

有输入饱和的欠驱动VTOL飞行器滑模控制

垂直起降飞行器(vertical take-off and landing,VTOL)是典型的非线性、欠驱动系统,实际工程中VTOL飞行器的执行机构通常有饱和特性,针对这种模型的特点,对原始数学模型进行了解耦坐标变换,通过可逆坐标变换化成一个最小相位系统和一个非最小相位系统,之后采用滑模设计方法设计控制器。为了解决执行机构的饱和问题,将超出饱和受限的部分回馈到控制器中,构造一个赫尔伍兹稳定的辅助线性系统,然后把它加入到滑模控制器之中,在控制器中做补偿。利用李雅普诺夫函数证明了系统的稳定性。仿真结果表明,此方法可有效地解决输入受限的VTOL飞行器的镇定和轨迹跟踪问题。     

一类欠驱动Lagrangian系统的位置同步控制

针对多个单输入欠驱动Lagrangian系统的同步控制问题,根据所定义的同步运动系统的同步误差信号,将各轴的位置误差与位置同步误差的比例耦合项作为新的状态变量,采用递阶滑模控制方法设计了一种交叉耦合位置同步控制器。采用该控制策略,对由两部一级倒立摆实际设备构成的同步运动装置的实时控制实验结果和4部一级倒立摆同步运动系统进行了仿真。仿真结果表明,在闭环系统精确跟踪指令信号的同时保证了各子系统间协调同步运动,而且该同步控制器的同步性能优于积分耦合同步控制器的性能。     

欠驱动机械系统控制设计综述

为了探讨欠驱动机械系统具有一般性的系统化控制设计方法,综述了目前关于欠驱动机械系统控制问题的具体应用和主要方法。基于欠驱动机械系统一般性的动力学描述,介绍了将其动力学转换成具有结构特征的三种级联非线性规范型的归约方法,归纳了针对三种级联规范型的一般性非线性控制方案,对今后欠驱动机械系统控制设计的研究发展方向进行了展望。     

光伏并网逆变器H_∞鲁棒控制策略的研究

光伏并网系统中,为了抑制逆变器参数不确定和电网干扰对输出电能的影响,提出了基于H∞鲁棒控制的光伏并网逆变器控制策略。在分析三相光伏并网逆变器的数学模型基础上,建立了包含不确定参数和电网干扰的模型,基于系统性能要求选取加权函数,并求得广义被控对象的状态空间实现,通过求解代数Riccati方程,得到H∞鲁棒控制器。通过仿真与传统PI控制方法进行比较,验证了该控制器对参数变化和电网干扰具有较强的鲁棒性。     

基于自适应方法的欠驱动AUV地形跟踪控制

为保证欠驱动智能水下机器人(AUV)面对干扰时具有更高精度的地形跟踪能力,提出一种自适应地形跟踪控制方法。首先,对某型欠驱动AUV进行了结构分析,建立了相关运动学及动力学模型;然后,提出一种结合模糊思想的自适应地形跟踪策略,并利用自抗扰控制建立相应运动控制器;最后,分别进行两组对比实验,以测试所设计地形跟踪方法的有效性。实验结果表明,所设计的欠驱动AUV自适应地形跟踪控制方法具有良好的响应能力,并且,相比于传统比例-积分-微分(PID)控制方法,能够更有效地抑制干扰所造成的震颤现象,具有更高的控制精确度。该控制方法的研究对提高欠驱动AUV在进行地形跟踪任务时的智能性具有一定意义。     

欠驱动水下机器人航迹跟踪控制

针对欠驱动水下机器人强非线性、模型不确定及存在外界未知干扰等特点,提出自适应模糊反演滑模控制系统,解决其水平面航迹跟踪问题。首先,采用模糊逻辑系统逼近模型未知函数,将反演思想与滑模控制技术相结合,设计反演滑模控制器;然后对水下机器人纵向速度进行控制,将航向角作为航迹跟踪误差的虚拟输入,设计航向角的镇定函数和航迹参数的变化率,实现水下机器人的航迹跟踪;最后使用李亚普诺夫稳定性定理,证明控制系统的稳定性。仿真实验表明,设计的控制系统能有效地处理水下机器人模型不确定性和外界干扰,控制性能良好,具有极强的鲁棒性,且避免了执行机构的抖振现象。     

一种交直流通用型欠电压脱扣器的设计

提出了一种新颖的电路设计方法,设计了一种交直流通用的欠电压脱扣器。通过BUCK开关电源技术解决了设备的自供电问题,并借助单片机实现了不同电网电压下的真有效值采样和脱扣执行机构的PWM驱动。试制了样机,通过产品的各项型式试验证明了设计方法的有效性。     

基于ESO的积分Terminal滑模励磁系统控制

发电机励磁系统是一个受参数摄动和外界干扰等因数影响很大的不确定非线性系统,针对此问题,本文通过构造扩张状态观测器(ESO)对发电机励磁系统的不确定因数进行估计,以实现非线性模型动态补偿线性化。为了克服常规滑模控制中被跟踪信号的导数均需已知的限制,在滑模面中引入了误差积分补偿项,然后利用Terminal滑模变结构控制理论设计励磁控制器。该控制方法能够有效地改善电力系统的静态和暂态特性。仿真结果验证了本文方法的可行性和有效性。     

A solution to leader following of underactuated surface vessels with actuator magnitude and rate limits

This article investigates the leader following of underactuated surface vessels that operate in the presence of environmental disturbances, model uncertainties, and actuator saturation. What makes the design of controller challenging is that the sway cannot be directly controlled. Furthermore, the actuator is formulated with magnitude saturation and rate saturation. To express the effect of magnitude saturation and rate saturation, a continuous function is employed to model actuator. An auxiliary dynamic system is used to solve the problem of magnitude saturation and rate saturation. A disturbance observer is designed to provide estimation of the environmental disturbances and model uncertainties, and achieve finite time convergence of estimation error. A control law is designed based on disturbance observer, backstepping technique, and auxiliary dynamic system. The uniform ultimate boundedness of all signals in the closed-loop control system is proved. Simulations demonstrate the performance of the proposed controller.     

一类欠驱动Euler-Lagrangian系统的同步控制

基于非线性系统反馈线性化方法得到了欠驱动Euler-Lagrangian系统的局部反馈线性化模型,并进一步应用小偏差线性化方法得到了此类系统的线性化模型.针对N个线性化后完全能控的欠驱动Euler-Lagrangian系统,提出了一种同步误差的构造方法,保证了包含N个系统原状态变量和各个系统同步误差信号的增广系统仍然完全能控,进而提出了一种最优同步控制器设计方法.对由两部一级直线倒立摆装置组成的欠驱动Euler-Lagranglian同步运动系统,采用上述方法设计了其最优同步控制器,并在实际的实验设备上进行了实时控制实验.实验结果表明,所提出的最优同步控制器实现了倒立摆装置的稳定平衡和小车位置的精确跟踪,并且令两个装置间达成了同步运动.与主从式同步控制方法相比,此最优同步控制器具有更好的同步效果.     

Adaptive IDA‐PBC for underactuated mechanical systems with constant disturbances

This work investigates the control of nonlinear underactuated mechanical systems with matched and unmatched constant disturbances. To this end, a new control strategy is proposed, which builds upon the interconnection‐and‐damping‐assignment passivity‐based control, augmenting it with an additional term for the purpose of disturbance compensation. In particular, the disturbances are estimated adaptively and then accounted for in the control law employing a new matching condition of algebraic nature. Stability conditions are discussed, and for comparison purposes, an alternative controller based on partial feedback linearization is presented. The effectiveness of the proposed approach is demonstrated with numerical simulations for three motivating examples: the inertia wheel pendulum, the disk‐on‐disk system, and the pendulum‐on‐cart system.     

Adaptive interconnection and damping assignment passivity-based control for an underactuated cable-driven robot

Interconnection and damping assignment passivity-based control (IDA-PBC) provides a general framework to stabilize underactuated mechanical systems by assigning the desired Hamiltonian to the system, which is obtained from the solution of partial differential equations. In this article, the IDA-PBC method is applied to an underactuated cable-driven robot to stabilize out-of-plane motion of the system. An adaptation law for the system's mass is designed such that asymptotic stability is ensured with positive tension in cables through the direct Lyapunov method. The results are verified through some simulations.     

具有不确定参数的车辆跟随滑模控制

假定车辆质量及作用在车辆上的空气阻力、地面对轮胎的摩擦力等参数随时间变化但有界,研究自动化公路系统车辆纵向跟随控制。根据车辆不确定参数的有界性和滑模控制策略,采用饱和函数法,设计了车辆跟随系统的纵向变结构控制规律;基于李雅普诺夫稳定性方法,对控制系统的稳定性进行分析,并确定系统收敛的充分条件。仿真结果表明:采用所设计的控制方法,在达到满意跟踪性能的同时,还能有效抑制控制颤振,对参数不确定性具有鲁棒性。     

多机器人的积分滑模编队控制

以一组非完整约束两轮机器人为研究对象,提出了具有非匹配不确定性的移动机器人系统的积分滑模编队控制。在单个机器人运动学模型的基础上,考虑机器人自身参数变化、打滑和侧移等不确定性的影响,采用领航-跟随机制,建立了编队系统的动力学模型。该动力学模型含有非匹配不确定性,无法应用积分滑模控制的不变性抑制。在合理的假设下,从理论上证明了具有非匹配不确定的编队系统在滑模阶段具有局部渐近稳定性;证明了提出的积分滑模编队控制律能够保证滑模的可达性条件。最后以三个机器人组成仿真实验平台,验证了在非匹配不确定性的了积分滑模编队控制方法的有效性及可行性。     

Adaptive control of an underactuated spherical robot with a dynamic stable equilibrium point using hierarchical sliding mode approach

Unlike the traditional underactuated mechanical system, the equilibrium point of the inner swing‐up suspension of a spherical robot possesses stable and dynamic characteristics. The stable dynamic equilibrium position of the underactuated suspension must agree well with the uncertain rolling resistance in practice. To overcome this special underactuated problem with dynamic equilibrium, we present an adaptive control scheme to enhance the ground adaptability using hierarchical sliding mode approach. The control method can drive the spherical robot to a desired position, and at the same time, the suspension subsystem holds on their dynamic equilibrium points rapidly. The proposed control approaches are verified to be effective by numerical simulation for a spherical robot to achieve satisfactory control performances, such as ground adaptability, rapid convergence, and disturbance rejection. Copyright © 2013 John Wiley & Sons, Ltd.     

Adaptive robust dynamic surface control with composite adaptation laws

This paper focuses on an adaptive robust dynamic surface control (ARDSC) with composite adaptation laws (CAL) for a class of uncertain nonlinear systems in semi‐strict feedback form. A simple and effective controller has been obtained by introducing dynamic surface control (DSC) technique and designing novel adaptation laws. First, the ‘explosion of terms’ problem caused by backstepping method in the traditional adaptive robust control (ARC) is avoided. Meanwhile, through a new proof philosophy the asymptotical output tracking that the ARC possesses is theoretically preserved. Second, when persistent excitation (PE) condition satisfies, true parameter estimates could be acquired via designing CALs which integrate the information of estimation errors. Finally, simulation results are presented to illustrate the effectiveness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.     

Adaptive robust control of nonlinear systems with dynamic uncertainties

In this paper, the discontinuous projection‐based adaptive robust control (ARC) approach is extended to a class of nonlinear systems subjected to parametric uncertainties as well as all three types of nonlinear uncertainties—uncertainties could be state‐dependent, time‐dependent, and/or dynamic. Departing from the existing robust adaptive control approach, the proposed approach differentiates between dynamic uncertainties with and without known structural information. Specifically, adaptive robust observers are constructed to eliminate the effect of dynamic uncertainties with known structural information for an improved steady‐state output tracking performance—asymptotic output tracking is achieved when the system is subjected to parametric uncertainties and dynamic uncertainties with known structural information only. In addition, dynamic normalization signals are introduced to construct ARC laws to deal with other uncertainties including dynamic uncertainties without known structural information not only for global stability but also for a guaranteed robust performance in general. Copyright © 2008 John Wiley & Sons, Ltd.