水厂加氯系统自动控制的设计与实现

介绍了某水厂加氯工艺的特点,并且对整个水处理加氯过程进行了分析,在工艺控制的基础上设定了控制策略,并且完成了加氯自动控制系统.由于水厂加氯非线性、不确定性强、大延时性等特点决定了现代水厂加氯系统无法取得精确的数学模型的特点,因此采用一般传统的控制方式来进行控制是不太现实的,最终提出了采用模糊控制先进控制算法进行控制策略.     

A nonlinear state‐feedback state‐feedforward tracking control strategy for a boiler‐turbine unit

A boiler‐turbine unit is a primary module for coal‐fired power plants, and an effective automatic control system is needed for the boiler‐turbine unit to track the load changes with the drum water level kept within an acceptable range. The aim of this paper is to develop a nonlinear tracking controller for the Bell‐Åström boiler‐turbine unit. A Takagi‐Sugeno fuzzy control system is introduced for the nonlinear modeling of the Bell‐Åström boiler‐turbine unit. Based on the Takagi‐Sugeno fuzzy models, a nonlinear tracking controller is developed, and the proposed control law is comprised of a state‐feedforward term and a state‐feedback term. The stability of the closed‐loop control system is analyzed on the basis of Lyapunov stability theory via the linear matrix inequality approach and Schur complement. Moreover, model uncertainties are also considered, and it is proved that with the proposed control law the tracking error converges to zero. To assess the performance of the proposed nonlinear state‐feedback state‐feedforward control strategy, a nonlinear model predictive control strategy and a linear strategy are presented as comparisons. The effectiveness and the advantages of the proposed nonlinear state‐feedback state‐feedforward control strategy are demonstrated by simulations.     

水厂深度处理自动控制系统的探讨及研究

论述了净水厂自动可能工资系统主要功能及组成,从活性炭滤池、臭氧接触以及V型滤池等工艺对自动控制系统进行了探讨。     

ICEAS工艺下污水处理厂的节能控制问题研究

综述了应用于国内外污水处理系统中的各种类型的控制模式和自控系统的特点,并结合污水处理厂ICEAS工艺的特点,研究确定了该厂的节能控制策略。该策略以学习控制为基础,既能够有效地降低能耗,又减少了系统对昂贵的在线仪表的过度依赖。在此基础上进行了软硬件的设计。     

Stabilising agent design for the control of interconnected systems

This article presents a new control design strategy for stabilising large-scale interconnected systems operating in semi-automatic control modes. The large-scale system is modelled by subsystems connected to each other in an arbitrary configuration. Each subsystem is regulated by a dedicated multivariable controller that also allows for a manual control mode. The notion of asymptotically positive realness constraint (APRC) is introduced and applied for deriving the interconnection stabilisability condition in the time domain. The interactions between subsystems are taken into consideration in the stability condition. The APRC is subsequently employed in the so-called stabilising agent to accommodate the closed-loop control and man-in-the-loop coexistence. The multipliers of the APRC quadratic supply rate are updated on-the-fly to ensure that the constraint satisfaction of stabilising agents is recursively feasible. The stabilising agents are developed independently from the control law under the same auspice controller. Due to this independence, operational errors from the manual control adjustments, that may destabilise the control systems, can be avoided. The decentralised agents render stabilising bounds for the manipulated variables in the automatic control mode, and at the same time, provide warning signals and manipulation guidance for the operators to prevent possible plant-wide destabilisation in the manual control mode. Our main results are illustrated through numerical simulations for an industrial modular system.     

Robust control and estimation of clutch-to-clutch shifts

Clutch-to-clutch shifts are ubiquitous in automatic transmissions, motivating the need for formal and robust methods for controlling these shifts. Limited sensing in production transmissions poses a severe hurdle for feedback control of these gearshifts. In the current study, nonlinear estimation methods are developed to compensate for limited sensing, and enable model-based closed loop control of the torque and inertia phases of shifts by manipulation of clutch pressures. During the torque phase, the offgoing clutch is controlled to emulate a one-way clutch, which ensures smooth coordination of the two clutches and reduced overall variation in the output shaft torque during the gearshift. During the inertia phase, the oncoming clutch is controlled to ensure smooth engagement at lock-up, resulting in reduction of shock and subsequent driveline oscillations. Controller performance is evaluated through numerical simulation of the proposed observer based controller on an experimentally validated high order model of a stepped production automatic transmission. The results show that shift control objectives were met by the proposed estimation and control strategy in the presence of appreciable model uncertainty and speed sensor noise, thus validating the robustness and practical effectiveness of the controller. Also, the proposed model-based controller was shown to be effective in controlling gearshifts at different power-levels (at different throttle openings), which establishes effectiveness of the same over a wide range of operating conditions.     

Real-time shared control system for space telerobotics

The shared control system is a modular real-time system designed to execute complex tasks through the intelligent coordination of task modules. A state machine is used to control task sequencing, and due to the automatic switching, the accuracy and reliability with which tasks are executed, is greatly improved. Tasks consist of sets of independent, modular, and reusable subtasks whose outputs are combined to create the control. This system has proved itself useful for rapid development of reliable high level multiple sensor based manipulation and control tasks. Additionally, we have integrated a neural network based visual servoing system, a semi-compliant Cartesian trajectory following heuristics, and a real-time graphical user interface in the system. The shared control system was implemented for the Self-Mobile Space Manipulator (SM ²) to handle a range of tasks associated with locomotion, manipulation, and material transportation on Space-Station Freedom.     

Non-linear economic model predictive control of water distribution networks

This paper addresses a non-linear economic model predictive control (EMPC) strategy for water distribution networks (WDNs). A WDN could be considered as a non-linear system described by differential-algebraic equations (DAEs) when flow and hydraulic head equations are considered. As in other process industries, the main operational goal of WDNs is the minimisation of the economic costs associated to pumping and water treatment, while guaranteeing water supply with required flows and pressures at all the control/demand nodes in the network. Other operational goals related to safety and reliability are usually sought. From a control point of view, EMPC is a suitable control strategy for WDNs since the optimal operation of the network cannot be established a priori by fixing reference volumes in the tanks. Alternatively, the EMPC strategy should determine the optimal filling/emptying sequence of the tanks taking into account that electricity price varies between day and night and that the demand also follows a 24-hour repetitive pattern. On the other hand, as a result of the ON/OFF operation of parallel pumps in pumping stations, a two-layer control scheme has been used: a non-linear EMPC strategy with hourly control interval is chosen in the upper layer and a pump scheduling approach with one-minute sampling time in the lower layer. Finally, closed-loop simulation results of applying the proposed control strategy to the D-Town water network are shown.     

Multiple-criteria optimization of pollution control model

This paper deals with a multiple-criteria optimization problem for the pollution control model which was introduced by Kulikowski. The model consists of n polluters which discharge the waste into the environment through waste treatment plants. The pollution of the environment, observed at m points, is expressed by a system of linear operators. The problem of multiple-criteria optimization for this pollution control model is formulated. The main difficulty of multiple-criteria optimization is that it is no longer clear what one means by an optimal solution. A possible remedy to this situation is to introduce an objective function which is expressed as a function of various criterions. Given the specific objective function, the optimum waste treatment strategy for the pollution control model is first determined with respect to another performance measure which is a linear combination of the various criterions. The optimum strategy for this performance is obtained in terms of the weighting factors in the linear combination functional. A search procedure is then used to determine the optimum values of those weighting factors for the specified objective function.     

Nonlinear cascade strategy for longitudinal control in automated vehicle guidance

This paper deals with automatic control design for automotive driving with a special focus on the longitudinal control. The automotive vehicle is a complex system characterised by highly nonlinear longitudinal and lateral coupled dynamics. Consequently, the control design for automated driving should deal with both of these dynamic couplings. Indeed, the longitudinal control plays an important role in the automated guidance to ensure safety and comfort of automotive passengers. In this work, a nonlinear cascade longitudinal control based on inner and outer-loops design is proposed. The lateral control is handled following a model predictive approach ensuring the automated steering of the vehicle. Finally, the nonlinear longitudinal control is integrated with the lateral control in a whole architecture to perform a coupled longitudinal and lateral control. The effectiveness of the automated driving strategy is highlighted through simulation results.     

Decentralised control of continuous Petri nets

This paper focuses on decentralised control of systems modelled by continuous Petri nets, in which a target marking control problem is discussed. In some previous works, an efficient ON/OFF strategy-based minimum-time controller was developed. Nevertheless, the convergence is only proved for subclasses like Choice-Free nets. For a general net, the pre-conditions of applying the ON/OFF strategy are not given; therefore, the application scope of the method is unclear. In this work, we provide two sufficient conditions of applying the ON/OFF strategy-based controller to general nets. Furthermore, an extended algorithm for general nets is proposed, in which control laws are computed based on some limited information, without knowing the detailed structure of subsystems.     

A supervisory control policy over an acoustic communication network

This paper presents a supervisory multi-agent control policy over an acoustic communication network subject to imperfections (packet dropout and transmission delay) for localisation of an underwater flow source (e.g., source of chemical pollution, fresh water, etc.) with an unknown location at the bottom of the ocean. A two-loop control policy combined with a coding strategy for reliable communication is presented to perform the above task. A simulator is developed and used to evaluate the trade-offs between quality of communication, transmission delay and control for a fleet of autonomous underwater vehicles supervised over a noisy acoustic communication network by an autonomous surface vessel. It is illustrated that without compensation of the effects of severe random packet dropout, localisation of an unknown underwater flow source is not possible for the condition simulated just by implementing a two-loop control policy. But a two-loop control policy combined with a strategy for reliable communication locates the unknown location of flow source.     

热轧带钢层流冷却控制方法

针对热轧带钢层流冷却终冷温度范围的扩大以及控制精度提高的要求,通过分析影响层流冷却过程的关键性因素如,速度、厚度、喷水量对终轧温度的影响,以及各因素之间相互的作用关系,合理制定出层流冷却的初始值,并建立起层流冷却温度控制的数学模型。运用前馈控制、速度补偿控制的思想以及针对层流冷却特点的线性叠加控制对层流冷却过程进行实时控制。所提出的方法成功运用于某层流冷却生产模型中,实现了终冷温度范围扩大以及控制精度提高的目标。     

Adaptive autonomous positioning of a robot vision system: Application to quality control on production lines

This paper presents an adaptive strategy for automatic camera placement in a 3-dimensional space during a robotized vision based quality control. The approach proposed improves the overall efficiency of the system, allowing a correct image acquisition, even in cases where an obstacle along the camera line-of-sight hides the object to be inspected, not making it possible to perform the inspection by template matching. In particular, a strategy for automatically avoiding a possible obstacle is defined.     

Robust modular control system design using an inner‐loop reference model and μ synthesis techniques

For complex dynamic systems, a modular control design process is often employed, wherein the overall design is partitioned into smaller modules. This paper considers a particular inner‐loop/outer‐loop modular control strategy in which the designer of the outer‐loop module does not know the specifics of the inner loop but instead possesses a reference model that captures the ideal inner‐loop input–output behavior. In the first part of this paper, we establish analytical properties of the modular reference‐model‐based design. In the second part, we introduce a novel mechanism, referred to as the modular control error compensation, which mitigates the performance loss that arises when the inner‐loop reference model is not matched. We propose an iterative algorithm, using μ synthesis, to design this compensator to reduce performance loss on the basis of two concrete worst‐case performance metrics. The effectiveness of the modular control strategy with the modular control error compensation is demonstrated through experimental results on an automotive system. Copyright © 2012 John Wiley & Sons, Ltd.     

Ant search based control optimisation strategy for a class of chaotic system

In this paper the authors propose a logistic mapping using chaotic model to describe the time-variable pest population. Two kinds of fuzzy rule embedded control strategies are investigated, three segment control and five segment control. They are designed to reduce the pest population. The simulation results show that the objective function is non-convex and anomalous along the control parameters. To find the optimal parameter combinations we develop an ant search approach. By imitating the food hunting and nest moving behaviours of Pachycondyla apicalis ants, this method can adaptively and effectively explore solution areas and arrive at the optimal solution. When we compared the performance curves with the one without control strategy, the method is better and can be used for a wide range of pest control problems in real life.     

基于西门子S7-300 PLC的生活污水处理厂自动控制系统

介绍了基于西门子S7-300 PLC的生活污水处理厂的自动控制系统,对整个污水处理厂各构筑物设备实现自动控制,提高了设备的利用率和污水处理厂的自动化程度,使出水排放稳定到达排放标准.     

Robust roll motion control of a vehicle using integrated control strategy

This paper presents an electrically actuated roll motion control of a vehicle using simulation and experimental analysis. The controller is designed with an H_∞ control scheme based on the 3 DOF vehicle model considering parameter variations, which affect the roll dynamics. To investigate the feasibility of the active roll control system, its performance is evaluated by simulation in a full vehicle model under various conditions. The Hil setup with the electrically actuated roll control system was devised and its performance was investigated through experimental works. Finally, to enhance the performance in a transient region, an integrated control strategy is presented.     

Stability overlay for adaptive control laws

This paper proposes an architecture referred to as Stability Overlay (SO) for adaptive control of a class of nonlinear time-varying plants. The SO can be implemented in parallel with a wide range of “performance-based” adaptive control laws, i.e., adaptive control laws that seek to improve closed-loop performance, but may be susceptible to instability in the presence of unaccounted model uncertainty. In this architecture, the performance-based adaptive control law designates candidate controllers based on performance considerations, while the SO supervises this selection based upon online robust stability considerations. A particular selection of a performance-based adaptive control law is not specified. Rather, this selection can be from a wide range of adaptive control schemes. This paper provides stability proofs for the SO architecture and presents a simulation that illustrates the applicability of the proposed method.     

悬臂式掘进机机身位姿误差消除策略的研究

基于悬臂式掘进机机身位姿检测系统,提出了一种悬臂式掘进机机身位姿误差消除策略:根据悬臂式掘进机机身位姿检测系统所采集的数据,判断各方向位姿误差的大小;当误差较大时,通过控制履带、前铲板与后支撑对悬臂式掘进机整体进行调整,减小机身各方向误差;当误差减小到截割臂的控制补偿范围,根据当前位姿误差设定截割轮廓的正确位置并进行自动截割;解算出各方向剩余位姿误差的补偿量,根据补偿量在自动刷帮过程中控制截割断面的边界位置。该策略对实现自动定向掘进和掘进远程控制具有一定的参考价值。