楼宇中央空调计算机监控系统的设计及实施

针对日益复杂的楼宇中央空调的监控要求,分析了楼宇中央空调控制系统的干扰因素,并重点阐述了空调湿度控制系统的特点.实验表明空调湿度控制系统具有一定的时变时滞特性,控制策略使用了鲁棒数字PII.该策略的主要控制思想是:"小"比例和积分控制实现时变时滞的鲁棒调节控制、修正积分控制抑制定值负载干扰.监控部分采用小型集散控制系统,并详细介绍了该监控系统的组成方案及仪表选型,最后简述了该监控方案的运行效果和节能效果.     

典型时滞时变过程的鲁棒数字双PI 控制

针对具有时滞时变以及负载干扰等复杂特性的时滞系统，在强时滞鲁棒数字PID控制方法的基础上，结合二自由度的IMC结构，给出一种数字双PI调节器的设计，在已知闭环系统时滞时变范围内，对确定性定值负载干扰的影响实现了无静差鲁棒调节控制。     

强时变时滞系统的鲁棒PID继电自整定控制技术

文章对于工业过程中常见的大时变时滞过程,提出了一种数字鲁棒PID控制器参数继电自整定控制策略和技术,应用这种整定方法整定的PID控制器,闭环不确定系统可具有大时变时滞鲁棒镇定性,且完全抑制负载干扰,具有很好的动静态性能,在造纸工业现场应用效果良好。     

典型大时变时滞工业过程的鲁棒数字PⅡ调节控制

通过分析典型大时变时滞工业过程的特性,提出了一种新的数字PⅡ鲁棒调节控制器 的设计方法.应用这种数字鲁棒控制器,闭环系统可具有大时变时滞鲁棒镇定性,且完全抑制定 值负载干扰.数字仿真验证了该方法的有效性.     

状态时滞时变不确定系统的鲁棒H∞ 输出反馈控制器设计

主要研究了存在状态滞后的线性时变不确定时滞系统的鲁棒∞控制分析和综合问题,给出了对所有容许不确定性,被控对象可二次镇定和满足从干扰输入到控制输出的Ｈ∞范数界约束的动态输入出反馈鲁棒Ｈ∞控制分析结果,将不确定时滞系统的鲁棒Ｈ∞输出反馈控制器设问题等价对两个线性时不变系统的状态反馈标准Ｈ∞控制问题,并由此得到反馈阵和观测阵,了终得到鲁棒Ｈ∞控制器综合设计方法。     

时变时滞不确定系统的鲁棒输出反馈控制

研究了时变时滞不确定系统基于状态观测器的动态输出反馈实现鲁棒镇定的分 析和综合问题.所研究的系统不仅同时包含时变状态时滞和时变控制时滞,而且包含时变未 知且有界不确定参数.提出了确保该系统可通过输出反馈鲁棒镇定的充分条件,并将该充分 条件转化为线性矩阵不等式(LMI)问题,最终通过求解两个LMI来构造输出反馈控制律.     

具有时滞的不确定鲁里叶控制系统的绝对鲁棒稳定性

讨论了具有时滞的非线性不确定鲁里叶控制系统的鲁棒绝对稳定性问题,应用Bellman-Gronwell不等式和Lyapunov泛函方法研究了不确定鲁里叶控制系统的鲁棒绝对稳定性并给出了系统的滞相关稳定和时滞无关稳定的充分判据,运用这些条件可以直接估计具有时滞的非线性不确定鲁里叶控制系统的鲁棒绝对稳定界和时滞界。     

执行器失效不确定时滞系统的指定衰减度鲁棒可靠控制

针对一类含有时变时滞的不确定参数线性系统,研究了在执行器发生故障情况下的鲁棒可靠控制器设计问题.系统中的参数不确定性满足广义匹配条件,时变时滞的大小及其变化率有界,并假设故障执行器元件的输出为零.经过适当的模型变换,将原系统的鲁棒指数镇定问题转化为另一个等价系统的鲁棒镇定问题.根据Lyapunov稳定性理论和线性矩阵不等式(LMI)方法,分别给出了鲁棒可靠控制器存在的时滞无关和时滞相关充分条件.仿真结果表明了该控制器设计方法的有效性.     

基于T-S模型的双时变时滞不确定系统的鲁棒H∞容错控制

为了解决系统在含有执行器局部或者完全失效故障情况下的鲁棒H∞容错控制问题, 针对一类状态和控制输入同时存在时变时滞的不确定非线性系统, 采用T-S模糊模型来描述, 利用并行分布补偿（PDC）算法设计了模糊状态反馈控制器, 结合Lyapunov稳定性理论给出了保证该模糊容错控制系统渐近稳定的充分条件, 不但保证了系统输出的鲁棒稳定性, 而且能够满足给定的鲁棒H∞性能指标。最后通过MATLAB仿真对比系统中有外部干扰和无外部干扰情况下的系统输出曲线, 验证了所提出方法的可行性。     

一类网络控制系统的鲁棒H∞状态反馈控制器设计

针对一类具有状态时变时滞且模型中具有参数摄动的网络控制系统,通过构造输入时滞、添加自由矩阵的技巧,利用Lyapunov 泛函和线性矩阵不等式工具,得到闭环系统鲁棒渐近稳定且满足给定H∞扰动抑制水平γ的时滞条件,并给出系统的鲁棒H∞状态反馈控制器的设计方法。所用方法适合时滞以任何速度变化的系统,且不需要知道时滞的导数信息。最后用实例仿真证明了结论的有效性。     

基于OneNET云平台的智能空调控制系统

针对空调耗电量大,因管理不善人为存在浪费的问题,文中提出并实现了一种基于OneNET云平台,通过增加外置智能空调控制终端模块对温湿度进行实时监控、对普通空调进行远程控制的系统.整个系统分为手机APP客户端、云上的虚拟设备及基于STM32的智能空调控制终端三大部分,适用于多种空调品牌.智能空调控制终端模块实时采集周边环境的温湿度数据上传云平台,用户通过手机APP实时查看环境数据并通过OneNET下发相应的控制指令给智能空调控制终端模块,终端模块通过红外通信方式控制空调.实验表明,利用该系统能实时监控环境温湿度数据,有效地控制空调合理使用,能营造舒适的生活工作环境又不造成浪费.     

Time‐varying input delay compensation for nonlinear systems with additive disturbance: An output feedback approach

This paper addresses the output feedback tracking control of a class of multiple‐input and multiple‐output nonlinear systems subject to time‐varying input delay and additive bounded disturbances. Based on the backstepping design approach, an output feedback robust controller is proposed by integrating an extended state observer and a novel robust controller, which uses a desired trajectory‐based feedforward term to achieve an improved model compensation and a robust delay compensation feedback term based on the finite integral of the past control values to compensate for the time‐varying input delay. The extended state observer can simultaneously estimate the unmeasurable system states and the additive disturbances only with the output measurement and delayed control input. The proposed controller theoretically guarantees prescribed transient performance and steady‐state tracking accuracy in spite of the presence of time‐varying input delay and additive bounded disturbances based on Lyapunov stability analysis by using a Lyapunov‐Krasovskii functional. A specific study on a 2‐link robot manipulator is performed; based on the system model and the proposed design procedure, a suitable controller is developed, and comparative simulation results are obtained to demonstrate the effectiveness of the developed control scheme.     

Adaptive passive control with varying time delay

This paper presents a passive control scheme for a force reflecting bilateral teleoperation system with a varying time communication delay. To improve the stability and performance of the system, the master and slave must be coupled dynamically via a transmission network through which the force and velocity are communicated bilaterally. However, the time delay caused by various factors, such as the transmission distance, network congestion, and communication bandwidth, is a long-standing impediment to bilateral control that can destabilize the system. In this study, we investigated how a varying time delay affects the stability of a teleoperation system. A new optimal adaptive approach based on a passive control scheme was designed bilaterally for both the master and slave sites. Extra variables were transmitted together with the wave variables in the scattering system. The proposed scheme achieved both passive control, and an acceptable tracking performance. The tracking performance was demonstrated using a computer simulation of varying time delays in a bilateral teleoperation system.     

变频技术在中央空调节能控制中的应用

本文提出中央空调系统的一种变频调速改造方案 ,介绍了该系统的结构组成及运行原理 ,对系统各部分的作用进行了讨论     

Approximate feedback linearization of a class of nonlinear systems with time-varying delays in states via matrix inequality

In this paper, feedback linearization method is proposed for nonlinear systems with a time varying delay in states. The diffeomorphism is presented to linearize the state-delayed nonlinear system if time-varying delay is known. Furthermore, we propose a control scheme to stabilize the approximate feedback linearizable system under the proposed conditions if the first order derivative of timevarying delay and the parametric uncertainties are finite and measurable.     

A Novel Predictive Control Scheme with an Enhanced Smith Predictor for Networked Control System

This paper presents a novel predictive control scheme with an enhanced Smith predictor for a networked control system with random time delays and system uncertainties. In the scheme, time axis is partitioned into equidistant small intervals to limit the continuous time varying delays into several discrete values. The stability of the networked control system is achieved by establishing an offline database and an online update strategy for Smith predictor, which reduces the reliance on the determined model of delay and system uncertainties in comparison with conventional Smith predictor. In this way, a sequence of finite forward predictive control signals of all possible time delays can be generated in advance and the actual delays will be compensated in real time when achieving the real delay information. Illustrative examples are given to demonstrate the effectiveness and robustness of the proposed predictive methods towards the random transmission delays and system uncertainties integrated in the networked control system.     

Adaptive tracking control of uncertain MIMO nonlinear systems with time-varying delays and unmodeled dynamics

In this paper, adaptive neural tracking control is proposed based on radial basis function neural networks (RBFNNs) for a class of multi-input multi-output (MIMO) nonlinear systems with completely unknown control directions, unknown dynamic disturbances, unmodeled dynamics, and uncertainties with time-varying delay. Using the Nussbaum function properties, the unknown control directions are dealt with. By constructing appropriate Lyapunov-Krasovskii functionals, the unknown upper bound functions of the time-varying delay uncertainties are compensated. The proposed control scheme does not need to calculate the integral of the delayed state functions. Using Young s inequality and RBFNNs, the assumption of unmodeled dynamics is relaxed. By theoretical analysis, the closed-loop control system is proved to be semi-globally uniformly ultimately bounded.     

An Efficient Finite Difference Method for The Time‐Delay Optimal Control Problems With Time‐Varying Delay

In this paper, an efficient finite difference method is presented for the solution of time‐delay optimal control problems with time‐varying delay in the state. By using the Pontryagin's maximum principle, the original time‐delay optimal control problem is first transformed into a system of coupled two‐point boundary value problems involving both delay and advance terms. Then the derived system is converted into a system of linear algebraic equations by using a second‐order finite difference formula and a Hermite interpolation polynomial for the first‐order derivatives and delay terms, respectively. The convergence analysis of the proposed approach is provided. The new scheme is also successful for the optimal control of time‐delay systems affected by external persistent disturbances. Numerical examples are included to demonstrate the validity and applicability of the new technique. Some comparative results are included to illustrate the effectiveness of the proposed method.     

Study on the sliding mode fault tolerant predictive control based on multi agent particle swarm optimization

For a class of uncertain discrete-time systems with time varying delay, the problem of robust fault-tolerant control for such systems is studied by combining the design of sliding mode control (SMC) and model predictive control (MPC). A sliding mode fault tolerant predictive control based on multi agent particle swarm optimization (PSO) is presented, and the design, analysis and proof of the scheme are given in detail. Firstly, the sliding mode prediction model of the system is designed by assigning poles of the output error of the system. The model has time varying characteristics, and it can improve the motion quality of the system while ensuring the sliding mode is stable. Secondly, a new discrete reference trajectory considering time-delay systems subjected simultaneously to parameter perturbations and disturbances is proposed, which not only can ensure that the state of the system has good robustness and fast convergence in the process of approaching sliding mode surface, but also can inhibit chattering phenomenon. Thirdly, the multi agent PSO improves the receding-horizon optimization, which can quickly and accurately solve the control laws satisfying the input constraints, and can effectively avoid falling into local extrema problem of the traditional PSO. Finally, the theoretical proof of robust stability of the proposed control scheme is given. Experimental results of quad-rotor helicopter semi physical simulation platform show that the state of uncertain discrete-time systems with time varying delay is stable under the action of the proposed control scheme in this paper. The advantages of fast response, less overshoot and small control chattering prove the feasibility and effectiveness of the proposed control scheme.     

ADAPTIVE ROBUST CONTROL OF UNCERTAIN SYSTEMS WITH TIME‐VARYING STATE DELAY

In this paper, a new adaptive robust control scheme is developed for a class of uncertain dynamical systems with time‐varying state delay, unknown parameters and disturbances. By incorporating adaptive techniques into the robust control method, we propose a continuous adaptive robust controller which guarantees the uniform boundedness of the system and at the same time, the regulating error enters an arbitrarily designated zone in a finite time. The proposed controller is independent of the time‐delay, hence it is applicable to a class of dynamical systems with uncertain time delays. The paper includes simulation studies demonstrating the performance of the proposed control scheme.