基于改进模型预测控制的加热炉温控系统研究

模型预测控制具有鲁棒性强、跟踪快速性好等特点,能够解决复杂工业过程控制中的大时滞问题。该文提出了一种改进的模型预测控制器,基于事先设定的期望响应,实现参考轨迹在预测时域内最大限度地渐进期望轨迹,使系统响应能够准确地跟踪期望轨迹。该文以硅单晶体加热炉为控制对象,分别采用PID、DMC和改进DMC三种控制方法进行预测控制。仿真结果表明改进的DMC控制方法比传统的预测控制方法具有更好的动态响应性能和跟踪效果。     

基于指令滤波的机械臂有限时间输出约束阻抗控制

提出一种基于指令滤波的机械臂有限时间输出约束阻抗控制方法.通过阻抗控制技术来解决机械臂与环境之间的相互作用,使机械臂跟踪期望轨迹.通过有限时间控制提高机械臂控制的响应速度,缩小跟踪误差,并引入障碍Lyapunov函数对机械臂末端输出状态进行约束.采用模糊自适应技术处理机械臂系统中的未知摩擦量和外部扰动量.仿真结果表明:该方法实现了对期望轨迹的有效跟踪控制,并且使机械臂输出状态都限制在预定义的约束空间中,具有更快的响应速度和更好的跟踪效果.     

位置跟踪系统的预测控制研究

在位置跟踪系统中,希望系统输出能快速,准确地跟随输入而变化。首先采用阶跃响应法建立了控制对象的数学模型,然后将预测控制的思想用于位置跟踪系统的控制,提出了位置控制器的一种设计方法,对有关设计参数的选择进行了讨论。并针对一快速成形系统的X轴永磁同步伺服电机的控制进行了仿真和实时控制实验研究,结果表明,所设计的控制器具有很好的跟踪性能和鲁棒性能。     

基于干扰观测器的时滞非线性切换系统滑模控制方法

为实现更加精准的时滞非线性切换系统滑模控制,应用干扰观测器设计一种新的系统滑模控制方法。构建时滞非线性切换系统模型,针对系统在发生结构变化时会产生复合干扰变化的情况,设计了一种非线性切换干扰观测器,实施系统不连续干扰的估计。通过 Backstepping 方法结合干扰观测器,设计一种切换滑模控制器,依据标量非线性特性打造一个滑模面,通过滑模控制器算法使时滞非线性切换系统能够满足滑模面的实际可达性条件,完成切换滑模控制器设计,实现系统的滑模控制。对设计的滑模控制方法进行测试,实验中选择的时滞非线性切换系统为一种变后掠翼 NSV 。实验结果表明,该设计方法能够实现较为准确地切入信号跟踪,表现出了很好的切换复合干扰估计性能。     

光电跟踪系统鲁棒自调整内模控制设计与分析

光电跟踪系统广泛应用于制导武器、航空航天观测设备以及靶场光电测量仪器等领域。针对光电成像测量时滞和模型不确定性,设计了一种鲁棒自调整内模控制算法。给出基于相位裕度和幅值裕度指标的系统控制器整定方程,分析得到了模型失配情况下的系统鲁棒稳定条件以及参数的设计准则,引入基于二次型性能指标的优化方法在线自适应调整控制滤波器参数来提高系统的控制性能和鲁棒性。在光电跟踪转台上的实验结果表明,所设计算法可有效地克服光电图像跟踪器测量时滞所造成的跟踪偏差,跟踪精度小于1密位,保证了成像传感器对目标的快速准确跟踪。     

预测函数控制及其在工业电加热炉中的应用

首先介绍并分析了预测函数控制方法的主要思想和特点,讨论了相应的控制器参数设计方法。进而针对典型的一阶时滞系统,给出了具体的预测函数控制器设计方法,并应用于一工业电加热炉对象的温度控制系统,取得了很好的控制效果。结果表明预测函数控制是一种具有较好控制精度,较快跟踪速度,良好动态特性的控制方法     

柔性臂杆、柔性关节空间机械臂TS模糊轨迹跟踪及双柔振动并行综合控制

针对存在参数不确定和外界干扰的柔性臂杆、柔性关节空间机械臂追踪期望运动的问题,设计了基于TS模糊模型的滑模鲁棒控制方案和双柔性振动并行控制方案。首先,设计了关节柔性补偿器以提高系统的等效关节刚度。其次,利用反馈线性化技术建立了系统追踪期望轨迹的误差动力学方程,通过对系统Lyapunov稳定性证明来选择滑模控制参数;简化并改进TS模糊推理规则,提出了模糊滑模鲁棒控制方法,可解决滑模控制的抖振问题并具有计算量少、控制力矩小的优点。再次,提出了柔性臂杆振动模态的直接反馈控制方案,解决了双柔性并行综合控制的问题。最后,运用逐步仿真的方法,对比仿真结果,证实了所设计轨迹跟踪、双柔性并行综合控制方案的有效性和稳定性。     

基于二自由度Smith的时滞过程控制系统的研究

针对串级时滞过程,提出一种二自由度Smith预估控制方法。主回路采用二自由度Smith预估控制,克服过程时滞的影响,同时使系统的设定值跟踪特性和干扰抑制特性解耦,通过控制器的设计,使系统同时获得良好的设定值跟踪特性、干扰抑制特性和鲁棒性。     

柔性结构振动跟踪控制H∞混合灵敏度法

基于H∞混合灵敏度控制算法,提出了一种将H∞混合灵敏度控制应用于高阶柔性结构振动跟踪控制的加权函数选择方法.该方法能够快速地使输出信号跟踪到参考信号.首先,建立了振动系统的多输入多输出跟踪控制模型;然后选择合适的性能加权函数和限幅加权函数,引入了模型的不确定性扰动,给出了一种针对高阶柔性控制系统的加权函数选择方法,利用混合灵敏度H∞控制设计方法,将鲁棒反馈控制器设计转化为标准H∞控制问题求解;最后,以一悬臂梁为研究对象,完成了两输入两输出结构振动控制的控制器设计和算法仿真.仿真结果表明,针对高阶柔性结构系统设计的控制器,在保证稳定性的前提下,输出信号对参考信号的跟踪结果满足了预定指标要求.     

反馈信号的滞后对混沌控制的影响

针对Pyragas延时反馈控制方法和自适应延时反馈控制方法，研究反馈信号滞后对混沌控制效果的影响。以信号滞后时间τ0作为分岔参数，得到控制系统状态变量对τ0的分岔图，该图表明信号滞后对两种混沌控制方法的控制效果均有不同程度的影响。与Pyragas延时反馈控制方法相比，自适应延时反馈控制方法具有较强的鲁棒性。另外，该方法能够在较短的时间内将混沌系统稳定在期望的周期轨道上。     

Generalized predictor based active disturbance rejection control for non-minimum phase systems

In this paper, a generalized predictor based control scheme is proposed to improve system performance of set-point tracking and disturbance rejection for non-minimum phase (NMP) systems. By using a generalized predictor to estimate the system output without time delay, a model-based extended state observer (MESO) is designed to simultaneously estimate the system state and disturbance. Accordingly, an active disturbance rejection control design is developed which consists of a state feedback control and a feedforward control for the disturbance rejection. The MESO and feedback controllers are analytically derived by specifying the desired characteristic roots of MESO and closed-loop system poles, respectively. To improve the output tracking performance, a pre-filter is designed based on a desired closed-loop transfer function for the set-point tracking. A sufficient condition guaranteeing robust stability of the closed-loop system against time-varying uncertainties is established in terms of linear matrix inequalities (LMIs). Three illustrative examples from the literature are used to demonstrate the effectiveness and merit of the proposed control scheme.     

Robust preview control for a class of uncertain discrete-time systems with time-varying delay

This paper proposes a concept of robust preview tracking control for uncertain discrete-time systems with time-varying delay. Firstly, a model transformation is employed for an uncertain discrete system with time-varying delay. Then, the auxiliary variables related to the system state and input are introduced to derive an augmented error system that includes future information on the reference signal. This leads to the tracking problem being transformed into a regulator problem. Finally, for the augmented error system, a sufficient condition of asymptotic stability is derived and the preview controller design method is proposed based on the scaled small gain theorem and linear matrix inequality (LMI) technique. The method proposed in this paper not only solves the difficulty problem of applying the difference operator to the time-varying matrices but also simplifies the structure of the augmented error system. The numerical simulation example also illustrates the effectiveness of the results presented in the paper.     

Input/output linearization using time delay control and time delay observer

In this paper, input/output linearization (IOL) method using time delay control (TDC) and time delay observer (TOO) is presented. This method enables the IOL method to be applied to plants even when all the states of plant are not measurable or the measured plant output is very noisy. The designed control system requires neither an accurate plant model nor the real time computation of plant nonlinearity. Consequently, the proposed control algorithm turned out to be computationally efficient and easy to design for nonlinear plants. In a simulation for a second order nonlinear plant, the output followed desired response well and the control performance appeared to be superior to IOL using TDC and numerical differentiation. Finally, in an experiment with a pneumatic servo system, we obtained results consistent with those from the simulation, and it was confirmed that the proposed control algorithm can be effectively used in a real closed-loop system.     

直流微电网中 DC-DC 变换器的切换控制方法研究

本文针对直流微电网中的DC-DC变换器进行了研究,以变换器的开关动作为切换信号建立线性切换系统模型,基于PWM波的特性提出一种新的切换控制方法用于DC-DC变换器网络。该切换控制方法既与时间有关又与系统状态有关,首先通过系统状态误差信号来确定每一周期内的切换时间且在周期的端点处必须切换,然后将周期内对应子系统的激活时间累加得到该周期的占空比。通过仿真和实验对比,可以看出该方法限定每个开关周期只进行一次切换,能够降低系统的切换频率,在负载需求波动时能够快速响应并将输出电压稳定在期望值的±1%内,验证了该切换控制方法的优越性。该方法的实施将在一定程度上降低直流微电网的损耗和提高其稳定性。     

双框架控制力矩陀螺框架系统的扰动观测及抑制

内外框架间的耦合力矩、非线性摩擦和未建模动态是影响双框架控制力矩陀螺框架系统高精度角速率伺服控制的主要因素。为提高框架系统的干扰抑制能力,保证框架系统输出角速率精度,本文提出了一种基于非线性级联扩张状态观测器和滑模控制的复合扰动抑制方法。框架系统中的所有干扰都被认为是集总干扰并由设计的NCESO估计,通过滑模控制可从系统输出通道中消除集总干扰的影响。最后,将本文提出的控制方法与线性级联扩张状态观测器和状态反馈结合的复合控制方法进行了对比仿真实验。仿真和实验结果表明,本文提出的方法具有更好的干扰抑制和动态响应性能,内框架角速度波动从0.5(°)/s减小到0.2(°)/s,外框架角速度波动从0.45(°)/s减小到0.15(°)/s;跟踪正弦参考信号时,速度跟踪误差从1.8(°)/s减小到1.2(°)/s,相位滞后从8°减小到1.3°。     

Tracking control of nonlinear lumped mechanical continuous-time systems: A model-based iterative learning approach

This paper presents a nonlinear model-based iterative learning control procedure to achieve accurate tracking control for nonlinear lumped mechanical continuous-time systems. The model structure used in this iterative learning control procedure is new and combines a linear state space model and a nonlinear feature space transformation. An intuitive two-step iterative algorithm to identify the model parameters is presented. It alternates between the estimation of the linear and the nonlinear model part. It is assumed that besides the input and output signals also the full state vector of the system is available for identification. A measurement and signal processing procedure to estimate these signals for lumped mechanical systems is presented. The iterative learning control procedure relies on the calculation of the input that generates a given model output, so-called offline model inversion. A new offline nonlinear model inversion method for continuous-time, nonlinear time-invariant, state space models based on Newton's method is presented and applied to the new model structure. This model inversion method is not restricted to minimum phase models. It requires only calculation of the first order derivatives of the state space model and is applicable to multivariable models. For periodic reference signals the method yields a compact implementation in the frequency domain. Moreover it is shown that a bandwidth can be specified up to which learning is allowed when using this inversion method in the iterative learning control procedure. Experimental results for a nonlinear single-input-single-output system corresponding to a quarter car on a hydraulic test rig are presented. It is shown that the new nonlinear approach outperforms the linear iterative learning control approach which is currently used in the automotive industry on durability test rigs.     

基于采样控制理论的光电跟踪伺服系统内模控制研究

针对外部扰动对光电跟踪伺服系统精度的影响,对稳定回路提出了一种两自由度内模控制,将控制器的设计转化为标准的H∞优化问题,使得系统对模型误差及参数摄动具有较强的鲁棒性。采用jump变换、提升操作等采样控制系统的理论与方法来优化设计相应的鲁棒控制器,综合考虑了系统的多采样率行为及采样点间的动态特性。仿真结果表明了所设计的控制系统具有较高的指令跟踪精度及较强的扰动抑制性能。本文的研究为高精度光电跟踪伺服控制系统的设计提供了新方法。     

Internal model control structure using adaptive inverse control strategy

In this paper, we propose a new adaptive internal model control scheme based on adaptive finite impulse response filters. This scheme provides the same design procedure for both minimum and nonminimum phase plants. The plants under consideration may contain time delay. The tracking objective is accomplished for both invertible and noninvertible stable plants. The internal model of the plant and its inverse are estimated by recursive least-squares and least-mean-squares algorithms, respectively. The closed loop is designed such that the system from the reference input to the plant output can be approximately represented by a pure delay. The effect of the process zeros on the output is compensated by using adaptive finite impulse response filters. This avoids the cancellation of noncancellable zeros of the plant and forces the plant output to track the reference input with a delay. The stability of the closed loop for both minimum and nonminimum phase systems is guaranteed. Computer simulation and laboratory scale experimental results are included in the paper to demonstrate the effectiveness of the proposed method.     

Model algorithm control for path tracking of wheeled mobile robots

This paper proposes a model algorithm control (MAC) method for the path tracking control of differentially steered wheeled mobile robots (WMRs) subject to nonholonomic constraints. The continuous dynamic model of the wheeled mobile robot is presented and used as the model to be controlled. The MAC controller is designed based on the sampled-data representation of the system. In this paper the case that there exists time delay in the control input is also considered. A time discretization method using the Taylor series and the zero-order-hold (ZOH) assumption is proposed to discretize the continuous dynamic model of the WMR. This time discretization method is especially useful in the case of the time delayed system. It can provide finite dimensional and more accurate discretized form model of the mobile robot with input time delay and convert it into a general nonlinear time discretized form to which the MAC controller can be applied. Simulations are conducted to show the performance and feasibility of the proposed control strategy. In these simulations the WMR is controlled to track two difference reference paths such as the “8” shape path and the circular path. The bounded inertial parameters uncertainties and some disturbance are also considered in the model of the control system.