Simulation on a Car Interior Aerodynamic Noise Control Based on Statistical Energy Analysis

How to simulate interior aerodynamic noise accurately is an important question of a car interior noise reduction. The unsteady aerodynamic pressure on body surfaces is proved to be the key effect factor of car interior aerodynamic noise control in high frequency on high speed. In this paper, a detail statistical energy analysis （SEA） model is built. And the vibra-acoustic power inputs are loaded on the model for the valid result of car interior noise analysis. The model is the solid foundation for further optimization on car interior noise control. After the most sensitive subsystems for the power contribution to car interior noise are pointed by SEA comprehensive analysis, the sound pressure level of car interior aerodynamic noise can be reduced by improving their sound and damping characteristics. The further vehicle testing results show that it is available to improve the interior acoustic performance by using detailed SEA model, which comprised by more than 80 subsystems, with the unsteady aerodynamic pressure calculation on body surfaces and the materials improvement of sound/damping properties. It is able to acquire more than 2 dB reduction on the central frequency in the spectrum over 800 Hz. The proposed optimization method can be looked as a reference of car interior aerodynamic noise control by the detail SEA model integrated unsteady computational fluid dynamics （CFD） and sensitivity analysis of acoustic contribution.

Active Noise Control of the Heavy Truck Interior Cab

In order to control the noise of the heavy truck interior cab effectively, the active noise control methods are employed. First, an interior noise field test for the heavy truck is performed, and frequencies of interior noise of this vehicle are analyzed. According to the spectrum analysis of acquired noise signal, it is found out that the main frequencies of interior noise are less than 800Hz. Then the least squares lattice （LSL） algorithm is used as signal processing algorithm of the controller and a closed-loop control DSP system, based on TMS 320VC5416, is developed. The residual signal at driver＇s ear is used as feedback signal. Lastly, the developed ANC system is loaded into the heavy truck cab, and controlling the noise at driver＇ s ear for that truck at different driving speeds is attempted. The noise control test results indicate that the cab interior noise is reduced averagely by 0.9 dBA at different driving speeds.

Nonlinear Control of Interior PMSM Using Control Lyapunov Functions

In this paper, we introduce a non-linear torque control for an interior permanent-magnet synchronous motor (IPMSM). The nonlinear control is based on a Control Lyapunov Function (CLF) technique. The proposed stabilizing feedback law for the IPMSM drive is a damping control method and is shown to be globally asymptotically stable. The CLF method takes the system nonlinearities into account in the control system design stage. Such nonlinearities are due to the cross coupling between the q and the q currents in addition to the system parameters like the inductances and the flux linkages. The complete IPMSM drive incorporating the proposed CLF has been successfully simulated in a plant model for both motor and inverter. The performance of the proposed drive is investigated in simulation at different operating conditions. It is found that the proposed control technique provides a good torque control performance for the IPMSM drive ensuring the global stability. In later work, we are planning to investigate other phenomena such as magnetic saturation, nonlinear loads, mechanical friction and flexibilities.

流媒体内后视镜及智能控制系统研究

现有的后视镜智能化程度低,无法对车身周围的实时环境进行监控、观察和报警,且不能将车辆后方的实时情况进行录像储存,车辆发生追尾等事故时,无法准确及时地判断事故发生原因。文章阐述了一种具备数字视频录像(DVR)记录功能的流媒体内后视镜及智能控制系统,可以通过控制系统中的系统级芯片(SOC)及时将车内摄像头、前摄像头和后视摄像头拍摄的图像,通过同轴线传输到后视镜显示屏上实时显示,并通过DVR同时记录至少一路以上的视频文件。基于流媒体内后视镜的智能控制系统可以实现前方、后方和车内三路视频监控及存储、语音提示报警和网络通信功能。

室内装修工程造价管理及目标成本控制策略研究

室内装修工程不仅涉及设计美学,更涵盖了工程预算、材料采购、施工管理等多个环节,每一环节的成本控制都直接影响到项目的经济效益。因此,文章对室内装修工程造价管理及目标成本控制进行了深入研究,以期找出优化管理策略,为相关人员提供参考。

基于改进龙贝格观测器的轨道交通IPMSM无感控制研究

针对轨道交通内置式永磁同步电机受IGBT开关频率限制难以实现高性能无感控制的问题,设计了一种基于龙贝格观测器的无位置传感器矢量控制。将电机电压方程改为基于扩展反电势的全阶模型,在此基础上进行龙贝格观测器的设计,从理论上分析了系统的稳定性,并给出参数设计方法。为了适应低开关频率应用环境,将观测器模型进行四阶离散化设计,以提高观测器的精度。以一台永磁同步电机作为控制对象,采用设计的无位置传感器控制进行试验验证。试验结果表明,设计的基于龙贝格观测器的无位置传感器控制转矩控制精度在2%以内,并且系统具有良好的负载突变动态特性。

Linear Programming for Optimum PID Controller Tuning

This work presents a new methodology based on Linear Programming (LP) to tune Proportional-Integral-Derivative (PID) control parameters. From a specification of a desired output time domain of the plant, a linear optimization system is proposed to adjust the PID controller leading the output signal to stable operation condition with minimum oscillations. The constraint set used in the optimization process is defined by using numerical integration approach. The generated optimization problem is convex and easily solved using an interior point algorithm. Results obtained using familiar plants from literature have shown that the proposed linear programming problem is very effective for tuning PID controllers.

Risk Control of Transmission Line Overload for Wind-Integrated Power Systems

With the rapid development of the wind generation,uncertainties of random wind and load bring some inevitable impacts on the security of power system. Once the uncertainty causes line power to exceed its limit, line overload will occur. The paper presents the risk control of transmission line overload for windintegrated power systems. Firstly, a risk control model of line overload is proposed considering the uncertainties of loads,generator outputs and wind powers. The generation cost and security level of system associated with overload can be optimally controlled. Then path following interior point method is employed to carry out the optimal control. Finally the simulation is made on the modified IEEE-30 bus system. Results show that the risk of line overload is effectively reduced through the optimization of control variables.

Rothe’s Fixed Point Theorem and the Controllability of the Benjamin-Bona-Mahony Equation with Impulses and Delay

For many control systems in real life, impulses and delays are intrinsic phenomena that do not modify their controllability. So we conjecture that under certain conditions the abrupt changes and delays as perturbations of a system do not destroy its controllability. There are many practical examples of impulsive control systems with delays, such as a chemical reactor system, a financial system with two state variables, the amount of money in a market and the savings rate of a central bank, and the growth of a population diffusing throughout its habitat modeled by a reaction-diffusion equation. In this paper we apply the Rothe’s Fixed Point Theorem to prove the interior approximate controllability of the following Benjamin Bona-Mohany(BBM) type equation with impulses and delay where and are constants, Ω is a domain in , ω is an open non-empty subset of Ω , denotes the characteristic function of the set ω , the distributed control , are continuous functions and the nonlinear functions are smooth enough functions satisfying some additional conditions.

Energy-Saving and Control of General Indoor Lighting Elements Fed from a Micro-Controlled Hybrid Power Generation System

In this study, an off grid wind-solar hybrid power generation system was established at Afyon Kocatepe University to meet the energy need of lighting system of three different laboratories. It is planned to efficiently use the energy obtained from the designed hybrid power generation system. For this purpose, PIC 16F877 was used in controlling of lighting load of laboratories. The off-grid wind-solar hybrid power generation system consists of 570 W 24 V mono crystal solar panels, 600 W wind power generation system and accumulator groups. The load control circuit made with PIC 16F877 is designed in a manner that will control the lighting armature groups individually activate and deactivate the armature groups according to intensity of illumination in environment. Besides, separately from generation and storing units constituting the hybrid power generation system, data in kWh are recorded by means of software in 10 seconds intervals. With the obtained power generation and storing data, analyzing of power consumption data when the load control system in active or passive position is made. According to analysis results, with controlling of lighting load and using of energy obtained from off grid wind-solar hybrid power generation system, 20.6% energy saving has been ensured.

基于RBF神经网络的汽车内饰皮革智能切割系统设计

随着汽车用皮革的迅速发展,开发一套满足汽车内饰皮革生产需求的智能切割系统具有重要意义。本文简述了汽车内饰皮革切割系统的发展,构建了基于径向基函数(Radial Basis Function,RBF)神经网络的汽车内饰皮革智能切割系统,介绍了系统主要硬件配置选型和软件的设计,提出了基于RBF神经网络PID(Proportional Integral Derivative,比例-积分-微分)控制算法;通过搭建试验平台,测试汽车内饰皮革智能切割系统的可行性、切割精度与效率。结果表明,该系统能够较好地满足汽车内饰皮革切割方面的需求。

Application of neural networks for permanent magnet synchronous motor direct torque control

Neural networks require a lot of training to understand the model of a plant or a process. Issues such as learning speed, stability, and weight convergence remain as areas of research and comparison of many training algorithms. The application of neural networks to control interior permanent magnet synchronous motor using direct torque control （DTC） is discussed. A neural network is used to emulate the state selector of the DTC. The neural networks used are the back-propagation and radial basis function. To reduce the training patterns and increase the execution speed of the training process, the inputs of switching table are converted to digital signals, i.e., one bit represent the flux error, one bit the torque error, and three bits the region of stator flux. Computer simulations of the motor and neural-network system using the two approaches are presented and compared. Discussions about the back-propagation and radial basis function as the most promising training techniques are presented, giving its advantages and disadvantages. The system using back-propagation and radial basis function networks controller has quick parallel speed and high torque response.

高速列车包间噪声特性及降噪方案设计验证

针对高速列车包间噪声问题及降噪措施进行了相关研究。首先,通过线路试验分析了高速列车包间噪声特性,包括噪声频谱、声源识别和声品质,掌握了包间中心与铺面上方测点的噪声差异,明确了包间噪声控制目标;其次,基于统计能量分析方法建立了高速列车包间噪声预测模型,并进行了试验验证,开展了包间声能量贡献分析,确定了降噪方案设计指标,进而对车体进行了隔声方案优化设计;最后,通过包间噪声的迭代预测,确定了车体降噪方案的可行性,并进行了线路试验验证。结果表明,采用笔者设计的降噪措施,包间噪声总值降低了3.2 dB(A),包间原本较高的响度和粗糙度得到明显控制,尖锐度也略有降低,声品质得到了优化。

基于延迟校正扩张状态观测器的内置式永磁同步电机电流控制策略

高速电驱动场合会受到开关频率的限制,低载波比特性凸显,由此引起的控制延迟问题影响了内置式永磁同步电机(IPMSM)矢量控制系统性能。基于扩展电动势的建模方案能够获得IPMSM的对称化模型,有利于离散化分析和设计,以提升低载波比运行性能。扩张状态观测器(ESO)能够实现扩展电动势和扰动的集总观测,然而低载波比延迟问题影响了估算性能。该文在离散域中分析延迟影响,设计和对比研究了几种延迟影响抑制方案,即延迟校正扩张状态观测器,提升了估计精度。基于此,设计了IPMSM离散域电流控制方案,显著提升了电流响应特性。通过电动汽车驱动实验平台验证了该文的分析和设计。

综合医院装配式内装修施工技术管控要点

以某医院项目的装配式装修为例,结合在施工过程中遇到的问题,从科学合理的界面划分及施工方案,部品、部件的选型,BIM技术的运用,样板间的实施引领等几个方面分析装配式装修在施工过程的技术管控要点,总结经验,为类似医院工程的装配式内装修设计及施工提供参考。

高校教学楼照明控制系统节能改造方案探讨及应用

建设年代久远的高校建筑在照明节能控制上有诸多问题,本文通过分析高校照明现状问题,结合高校照明按不同时段使用的特点,给出智能照明控制和人体感应控制相结合的照明控制思路,并以某高校教学楼室内照明改造设计案例进行探讨。

内置式永磁同步电机宽速域模糊滑模控制

针对传统内置式永磁同步电机控制策略抗干扰性能较差、参数摄动和控制精度的问题,提出了基于超扭曲扰动观测器的模糊滑模控制策略,实现了内置式永磁同步电机的宽速域运行,同时进一步提高了转速跟踪精度和系统的抗干扰能力。首先,通过最大转矩电流比与梯度下降法弱磁控制相结合拓宽了调速范围。其次,基于超扭曲算法(STA)设计扰动观测器,提升了系统的抗干扰能力。同时,为了应对Backstepping算法中的微分膨胀问题,使用二阶滑模微分器对虚拟控制率作逼近处理。采用模糊逻辑系统对内置式永磁同步电机模型中的非线性部分进行逼近,降低电机参数摄动对控制性能的影响。最后,通过应用Lyapunov理论,验证了所提控制策略的稳定性。通过Matlab/Simulink平台进行仿真,验证了在所提控制策略下内置式永磁同步电机具有更优异的宽速域动态性能和鲁棒性。

基于EKF的IPMSM无位置传感器控制估计误差补偿方法

在基于扩展卡尔曼滤波(EKF)法的内置式永磁同步电机无位置传感器控制系统中,电机转速和转子位置的准确估计十分重要。针对相电流增益误差导致的转速和转子位置估计精度下降的问题,提出一种位置估计误差补偿方法。首先,理论推导得出,在扩展卡尔曼滤波器估算过程中,相电流增益误差会使估计转速及转子位置以二倍工频的频率振荡。其次,设计了一种新型结构扩展卡尔曼滤波观测器,即在传统扩展卡尔曼滤波观测器的基础上增加增益误差系数求解环节,以此来降低相电流增益误差引起的估计转速及转子位置的脉动,提高了估计精度。最后,仿真和试验验证了所提补偿方法的可行性。

动车组旅客列车车内空气质量控制技术研究

动车组列车运行时间长、乘员密度大,导致车内空气质量欠佳,针对该问题,文章通过数值模拟方法和消杀试验分析了列车新风量、送风模式及主动消杀装置对车内空气质量的影响。分析结果表明,新风量从1350 m3/h增加至1800 m3/h时,客室内颗粒物更易向前端废排口扩散并被捕获;70%顶部送风+30%底部送风模式较全顶部与全底部送风而言,前20s客室内颗粒物纵向扩散范围显著扩大,颗粒物向废排口扩散能力增强;石墨烯静电消杀措施在5 min和15 min采样时刻的细菌消杀作用显著,过道处测点和座椅处测点的平均消杀率均在34%以上。研究结果可为现役动车组旅客列车的车内空气质量控制提供指导。

城轨车辆噪声多因素影响分析及控制措施

城轨车辆的噪声水平成为主要关注的问题之一,主要噪声源是轮轨噪声,轮轨噪声同时受到车辆-轨道耦合作用、曲线段多等多因素影响,导致长时间运行过程中噪声增大5~10 dB,严重影响乘客舒适性。基于国内城轨车辆线路实际调研结果,分析轨道条件、小曲线、明线和隧道等多因素对车内噪声水平的影响。在分析基础上,提出相应的控制措施,给予车辆及线路设计以指导意义,提高旅客乘坐舒适性。