Particle identification using artificial neural networks at BESⅢ

A multilayered perceptrons' neural network technique has been applied in the particle identification at BESⅢ. The networks are trained in each sub-detector level. The NN output of sub-detectors can be sent to a sequential network or be constructed as PDFs for a likelihood. Good muon-ID, electron-ID and hadron-ID are obtained from the networks by using the simulated Monte Carlo samples.     

轴向数控磁力轴承系统的研究

本文建立了轴向磁力轴承的动力学方程和数学模型 ,阐述了基于数学模型分析的数字控制系统的设计方法 .介绍了本课题设计的新型数字控制系统 .试验表明该系统具有较好的控制稳定性和运转稳定性 ,具有较强的承载力 .     

30℃～420℃黑体温度控制及自整定研究

作为红外标准光源,要求30℃～420℃黑体能快速升温到设定温度点,并保持温度稳定。针对其升降温功率差别大、滞后大等特点,用开关控制冲击响应自整定方法,得到黑体温升超调量、最大升降温速率等参数,采用复合智能温控策略,实现了30℃～420℃黑体温升前期快,接近设置温度时改以渐进方式达到并稳定在设定温度点。实验结果表明,实现了30℃～420℃黑体无超调地到达设定温度点,且稳定性为±0.03℃/min,该指标达到了国际同类产品水平。     

基于BP神经网络的多升降台同步控制研究

大型分布式升降台控制系统中,其同步控制是最关键的问题之一。针对传统神经网络PID控制器在多升降台同步控制的结构复杂及同步时间长等问题,提出一种基于相邻偏差耦合控制结构的BP神经网络PID同步控制策略,在确定同步误差定义的基础上,建立异步电机的矢量控制模型,改进了BP神经网络同步控制器。对多升降台同步控制系统的仿真实验表明：所研究的控制策略同步误差小,收敛速度快,实用性强。     

基于自适应遗传算法的改进PID参数优化

PID控制的控制性能取决于PID参数的设置,针对传统PID参数整定和优化过程中存在的问题进行了PID控制改进,提出了自适应遗传算法整定和优化PID参数的方法。改进PID控制将系统的综合性能控制区分为不同目标的局部性能控制,采用自适应遗传算法针对不同控制目标进行PID参数寻优,选择、交叉和变异概率的自适应改变在保持种群多样性的同时加快算法收敛。改进的PID控制和遗传算法有效提高了PID参数寻优能力,提高了控制系统的响应能力和稳定性。最后通过发动机怠速转速控制应用表明本算法的可行性和有效性。     

小潜艇供电系统全桥DC-DC开关电源智能优化设计

小型潜艇水下潜行采用蓄电池供电,通过全电力供电系统推进。以蓄电池为直流电源,在推进系统正常运转的状况下,开关电源电压输出值保持恒定。传统的PID控制器很难对全桥DC-DC开关电源进行精确控制,因此,将粒子群算法(PSO)、BP神经网络与径向基函数(RBF)神经网络与传统PID控制相结合,提出带有RBF神经网络辨识的PSO-BP-PID控制方法。通过神经网络在线自学习对PID三个参数在线调整,最终实现系统恒电压输出控制。仿真结果得出：带有RBF神经网络辨识的PSO-BP-PID控制算法可以很大的改善系统控制效果,同时使系统具有更好的在线调整能力。     

Algorithms to control the moving ship during harbour entry

Automation is being accepted for control systems onboard ships in view of the shortage of skilled manpower in marine sector. Control theory has long been applied to maneuvering problems and at present this trend is continuing at an increased rate. This is for speed control, course control and path keeping. Heading control and course keeping are very important for surface ships while they enter shallow water regions. A typical situation is the entry of a large commercial ship into the harbour basin. The ship faces a sudden change of forces and moments around it due to the change in the hydrodynamics. The Master of the ship regulates the speed while entering the basin. Forces and moments, due to the hydrodynamic flow around the moving hull, are balanced by the rudder behind it. The feed back from the heading angle is taken and the gain in the control system prompts the steering gear to turn the rudder. The conventional control algorithm based on PID is attempted in the first part of the paper and case studies are shown for a Mariner class ship whose hydrodynamic derivatives are known. Displacement, velocities and accelerations are determined for short duration from the simulation of a voyage in calm water. The proposed system can be implemented into autopilot systems. The codes developed in MATLAB can accommodate wind and wave forces as well. The simulation is of a general type and can be used for other vessels with a change in the constants of P (Proportional), I (Integral) and D (Derivative) which can be arrived at by trial and error. The design of the control system depends on the choice of the three control constants K_p, K_i and K_d. These will change as per sea state and extra loads. The control of motions in shallow water and deep water cases are discussed in the paper.     

基于改进PSO的超声雾化电源频率跟踪研究*

超声波雾化技术由于其良好的雾化效果获得了广泛关注，具有极大的研究价值和应用前景。但是在超声雾化的过程中，由于换能器的温度变化、刚度变化以及在水中的负载变化等因素，会产生谐振频率漂移的现象。当工作频率偏移谐振频率时，将造成换能器的工作效率降低和元器件损坏等问题。针对此问题，设计了基于改进粒子群算法优化PID参数的超声雾化电源频率跟踪算法，并对该算法进行频率跟踪的仿真验证和实验对比，在频率跟踪上实现了更好的效果，使换能器能够稳定工作在谐振状态，提高了电源的利用率。     

Load distribution control system design for a semi-track air-cushion vehicle

This paper describes the design principle for a semi-track air-cushion vehicle working on soft terrain. A novel structure, i.e., a flexible joint mechanism is designed for the semi-track air-cushion vehicle suspension system. Focusing on optimizing the total power consumption of the vehicle, three main issues were studied in this paper. First, a theoretical model for minimizing the total power demand of the vehicle is developed. The effects of load distribution on total rolling resistance and total power requirement are calculated which are compared with the prototype experiment data. Second, the optimization procedure is presented. Third, a control scheme is proposed to minimize the power consumption by using a self-tuning PID fuzzy controller and the feasibility was examined by the simulations performed in Matlab/Simulink software environment.     

基于信号约束块的水轮机调速器的PID优化

PID控制是应用比较普遍的控制方式之一，但在控制要求以及控制对象变化的情况下，其传统的参数整定方法难以满足系统调节品质的要求．针对使用PID控制的水轮机调节系统以及基于MATLAB7中的Simulink响应优化工具，讨论了水轮机调速系统在具有参数不确定性的情况下，如何调整PID的3个参数以满足给定的性能指标要求．仿真结果表明：使用信号约束模块可快速和有效地完成PID控制器参数优化任务，不仅使系统响应满足性能指标要求，而且还有较强的抗干扰能力和鲁棒性，具有一定的参考使用价值．