模糊PID控制在锅炉燃烧系统中的应用

针对目前锅炉存在的能耗高、燃烧不完全、污染环境、热效率低的缺点,设计了一种新型锅炉燃烧系统.该系统采用PID串级和Vague集分时控制,有效地提高了锅炉控制质量.     

Suboptimal digital control systems with bounded control inputs

Bounds on the control inputs to a linear system are dealt with in a manner suitable for online computer control. The method guarantees that for r control inputs the constrained optimum will be located in, at most, r steps.     

水泥配料控制中控制算法的研究

配料是水泥生产过程的重要环节,在一些连续称量配料工艺过程中,以往大多通过控制每种物料的瞬时流量来满足工艺要求,但往往误差较大,给生产带来不良影响。为提高控制精度,提出了一种偏差加权累积量控制PID算法,并在水泥生料配料控制中进行了实施,实验结果表明该算法能有效地抑制和消除系统过量超调和不停振荡,且对于某些不要求每个瞬时值都控制给定值的量,该算法可以避免调节阀的频繁动作并大大提高调节品质。偏差加权累积的PID控制算法具有简单、方便、易于实现的特点,且在水泥生料配料控制中取得了理想的效果,有很好的推广前景。     

Adaptive ABR congestion control with active buffer control

ATM Forum has defined that the ABR service is designed mainly for data traffic. The design of a simple and efficient congestion control scheme is a problem that network managers have to face. In this paper, we propose a control scheme for ABR service for better scalability and response. The scheme uses both the load level and an increase in queue length to detect the presence of congestion. Continuous control functions are designed for the bandwidth allocation. A better buffer control is achieved by incorporating the percentage of buffer occupancy into the control function. All of the control functions are designed in such a way that they are sensitive to the change of the system states when they are far from the optimal level to get a fast response, but insensitive and change slowly when the states are close to the optimal level to keep the system around the steady state. Our simulation results show that the algorithm is fair to all the connections and it converges fast when the network's condition changes. Copyright © 2001 John Wiley & Sons, Ltd.     

Content-based deep communication control for networked control system

In smart cities, the networked control system plays a significant role in transportation systems, power stations or other critical infrastructures, and it is facing many security issues. From this point, this paper proposes a content-based deep communication control approach to guarantee its security. Based on the layer architecture, this approach analyzes the interactive content in depth according to different industrial communication protocols, and implements the access control between two distinct enclaves. For OPC Classic, we acquire the dynamic port provided by OPC server, and open a new connection belonging to this port; for Modbus/TCP, we not only analyze the ordinary function codes and addresses, but also check the register or coil values by using the multi-bit Trie-tree matching algorithm. Besides, the white-listing strategy is introduced to satisfy the special requirements of industrial communication. Our experiment results show that, on the one hand the proposed approach provides OPC and Modbus/TCP defenses in depth; on the other hand it has less than 1 ms forwarding latency and 0 packet loss rate when the rule number reaches 200, and all these meet the availability requirements in the networked control system. In particular, this approach has been successfully applied in several real-world petrochemical control systems.     

基于自适应模糊理论的某型无人机起飞控制方法

基于合理简化的无人机纵向模型,设计了一种自适应模糊控制器,该控制器将Takagi-Sugeno模糊系统与等效控制器相结合,以增强系统的鲁棒性.只要求预先知道系统的相对阶以及未知函数的上下界即可,不需要精确的数学模型.Lyapunov合成方法证明了跟踪误差能趋近于零且其余的控制信号均有界.最后,结合优先级按比例分配的控制分配器,给出了存在扰动情况下飞行控制系统的仿真结果,表明即使在模型部分未知的情况下,该系统仍然能够达到飞行控制的指标性能和品质要求,验证了该方法的有效性.     

基于TRICON控制系统防喘振控制算法

喘振是造成压缩机损坏的重要原因,在此针对某厂70万吨/年烯烃项目,根据丙烯工艺流程,设计了一套压缩机的防喘振控制系统。该控制系统以TRIEW软件为人机界面,利用TRICON独有的防喘振控制软件包,将喘振PID控制、喘振超驰、手动控制算法相结合,通过喘振PID参数的在线优化,有效地实现了压缩机的防喘振控制,现场实际运行结果表明了该系统的稳定性和可靠性,同时,验证了该喘振控制算法的有效性。     

Modeling and control for smart Mesoflap aeroelastic control

This paper introduces a novel concept termed Smart Mesoflaps for Aeroelastic Recirculation Transpiration (SMART) to render mass and momentum transfer for controlling shock/boundary-layer interactions in supersonic jet inlets. The SMART concept consists of a matrix of small flaps designed to undergo local aeroelastic deflection to achieve proper mass bleed or injection when subjected to shock loads. To optimize the performance of this system, NiTi shape memory alloy is used as an actuator for the flaps to control the amount of recirculation. The focus of this paper will be the subsystem modeling and control of a single flap. After a relatively detailed model is developed, a simpler model is generated, and it is experimentally shown that this approximation is adequate for control purposes. Next, the control strategy for this subsystem, subject to hysteresis and actuator saturation, is presented. A basic proportional integral derivative (PID) controller is enhanced using a hysteresis compensator (HC) and an error governor (EG). A generalized error governing scheme for PID controllers to compensate for actuator saturations is also developed. This EG method is generalizable to any stable process controlled by a PID. Finally, the PID with HC and the error governing method is experimentally applied to a benchtop SMART subsystem.     

Throttle actuator control system for vehicle traction control

Accurate and quick positioning of the throttle valve in a gasoline engine is required to implement various systems such as traction control systems (TCS), cruise control systems and drive-by-wire systems. In this research, the throttle actuator system for TCS application was developed. Unlike other systems, this system consists of only one throttle body to obtain small volume and low manufacturing cost, and uses a DC servo motor for quick and accurate responses. In order to drive the DC motor, a PWM signal generator and PWM amplifier were built and interfaced to the motor and controller. This paper also presents the position control logic of the throttle actuator with the TDC (time delay control) scheme with a variable reference model. By varying the reference model based on the size of the step changes in the target throttle angle, the TDC scheme yields good transient response characteristics in that both overshoot prevention and a quick response time are achieved. Actual vehicle tests with this developed system incorporated with the TCS system show that it satisfies all the conditions required for the TCS operation.     

全自动洗衣机控制电路的PLC自动控制

针对典型全自动洗衣机的实际控制要求,运用三菱PLC顺序控制步进STL指令编程方法,在I/O分配的基础上,进行PLC梯形图程序设计,并对程序运行功能予以分析说明。经过PLC上机模拟调试,与实际控制要求完全一致。     

Application of modern control techniques to motor control

An overview is presented of digital control problems arising in the use of microprocessors and the application of modern control theory, from both the theoretical and practical viewpoints. The discussion covers optimal control, robust control, feedback and feed-forward control, and active and passive adaptive control. Various application are described, drawing on the author's own experience. It is concluded that a robust optimal digital controller for motor control can be practically designed and implemented with currently available techniques and hardware     

带遥控和自动温控功能的PWM控制器

介绍一种实用的带有遥控控制功能、自动温控功能、以PWM方式输出控制信号的多功能控制器模块,其特点是充分应用了Z8单片机的内部硬件资源以同时实现多种功能。阐明了最大限度开发单片机听基本思路和方法,可应用到其它单片它系统中。     

Echelon-networking control

Distributed manufacturing control offers more functionality than centralised systems, but normally at the cost of coordination and `intelligence'. Here, the author describes a unique solution from Palo Alto-based Echelon Corporation and its semiconductor partners, Motorola and Toshiba. Instead of simply defining a network protocol, Echelon has developed a sophisticated microcontroller (the Neuron) with networking and interfacing built in. Neuron networks can run on various media, including twisted pair, radio or power lines. The system uses an OSI seven-layer network protocol, involving three microprocessors in a classic multiprocessing environment, using shared memory as their communication link. Advanced manufacturing techniques have integrated the three processors with memory at a cost comparable with an off-the-shelf single-chip microcontroller     

Highway control

The world grows evermore congested but the demand for personal mobility is undiminished. The author describes how technology can keep the traveller on the move. Two obvious corrective measures would be to restrict the use of private cars and to build new roads. Both approaches are political minefields. Car owners do not welcome limitations on their personal mobility, and there is little public support for road building on the scale needed to expand capacity in line with demand. Confronted by such difficulties, government and traffic authorities are increasingly turning to modern information systems as a means of developing alternative approaches to the control of traffic and the management of demand. The author describes the SCOOT system, a real time traffic light control system, and the variable speed limit signs on the M25. The further development of such systems and concepts is the provision of real-time traffic information, which is discussed by the author     

Transverse mode control in long-monolithic-cavity VCSELs with temperature-profile control

Transverse mode control by using temperature-profile control in VCSELs with a large active area of more than 10 /spl mu/m diameter is demonstrated. From spectrum measurement, higher-order mode suppression was observed as power increased for a heater introduced for temperature-profile control. The far-field pattern without heating had two peaks and it changed to a Gaussian shape with heating.     

Iterative power control based admission control for wireless networks

This paper studies transmission power control algorithms for cellular networks. One of the challenges in commonly used iterative mechanisms to achieve this is to identify if the iteration will converge since convergence indicates feasibility of transmit power allocation under prevailing network conditions. The convergence criterion should also be simple to calculate given the time constraints in a real-time wireless network. Towards this goal, this paper derives simple sufficient conditions for convergence of an iterative power control algorithm using existing bounds from matrix theory. With the help of suitable numerical examples, it is shown that the allocated transmit powers of the nodes converge when sufficient conditions are satisfied, and diverge when they are not satisfied. This forms the basis for an efficient link data-rate based admission control mechanism for wireless networks. The mechanism considers parameters such as signal strength requirement, link datarate requirement, and number of nodes in the system. Simulation based analysis shows that existing links are able to maintain their desired datarates despite the addition of new wireless links.     

基于单片机的水位控制系统设计

基于单片机控制步进电机的水位控制系统,通过金属棒和水的导电性采集水位信号,结合了单片机输出电平控制继电器来控制抽水机的实验,实现了连续控制和跟踪水位,并以液晶实时显示水位。该方案具有原理简单、想法新颖、容易实现、精度高等特点,控制系统对于提高工业自动化水平和提高生活供水质量具有重要的意义。     

基于复合控制的自行车机器人平衡控制

为了实现自行车机器人的平衡控制,提出一种复合控制的方法。将自行车看成多体系统,根据拉格朗日方程建立系统动力学模型。针对自行车机器人不稳定零动态的特点,采用复合控制,将系统的不稳定子系统作为内环,采用二次型性能指标最优控制器镇定。针对干扰以及模型不确定性,对输出作为反馈的外环设计鲁棒控制器,使得整个系统具有较强的鲁棒性。仿真结果表明,所提方法可以实现自行车的平衡控制,使系统具备了抑制干扰的能力,并保证了系统的鲁棒稳定性。     

Minimum-time minimum-loss speed control of induction motors underfield-oriented control

A new minimum-time minimum-loss speed control algorithm for induction motors is suggested to obtain high performance, as well as high efficiency, under field-oriented control with practical constraints on voltage and current. This algorithm utilizes a two-stage control. In the transient stage, a maximum torque control algorithm is utilized to get the minimum-time response. In the steady state, a minimum-loss control algorithm is applied to improve the efficiency. Simulation studies show the performance of the proposed minimum-time minimum-loss control algorithm under field-oriented control