Study on a Closed-Loop Air-Fuel Control System of Gasoline Engines by Simulation

In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model of closed loop control system including the engine, air fuel mixing and transportation, oxygen sensor and controller, etc., is developed. Various factors that influence the A/F control are studied by simulation. The simulation results show that the reference voltage of oxygen sensor will influence the mean value of A/F ratio, the controller parameters will influence the amplitude of A/F fluctuation, and the operating conditions of the engine determine the frequency of A/F fluctuations, the amplitude of A/F fluctuation can be reduced to within demanded values by logical selection of the signal acquisition method and controller parameters. Higher A/F fluctuation frequency under high speed and load can be reduced through software delay in the controller. The A/F closed loop control system based on the simulation results, accompanied with a rare earth element TWC, gives a better efficiency of conversion against harmful emissions.

Simulation of Automotive Engine Phase Signal Based on Closed-Loop Strategy

In this paper, an automotive engine phase signal simulation algorithm is proposed based on a closed-loop feedback strategy, and its corresponding model is built. The signal incentives are carried out in the front-end, and the synchronization capture and comparison are conducted in the back-end. The phase simulation of signal output is achieved using closed-loop strategy, which can effectively eliminate the inconsistency between crankshaft and camshaft phases, and thus the accuracy and flexibility of phase signal generation are guaranteed. Experimental results show that the proposed algorithm is real time, and the deviation of simulated signals from actual phase signals is small. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

Joint Closed-Loop Power Control and Adaptive Beamforming for Wireless Networks with Antenna Arrays in a 2D Urban Environment

The interference reduction capability of antenna arrays and the power control algorithms have been considered separately as means to decrease the interference in wireless communication networks. In this paper, we propose smart step closed-loop power control (SSPC) algorithm in wireless networks in a 2D urban environment with constrained least mean squared (CLMS) algorithm. This algorithm is capable of efficiently adapting according to the environment and able to permanently maintain the chosen frequency response in the look direction while minimizing the output power of the array. Also, we present switched-beam (SB) technique for enhancing signal to interference plus noise ratio (SINR) in wireless networks. Also, we study an analytical approach for the evaluation of the impact of power control error (PCE) on wireless networks in a 2D urban environment. The simulation results indicate that the convergence speed of the SSPC algorithm is faster than other algorithms. Also, we observe that significant saving in total transmit power (TTP) are possible with our proposed algorithm. Finally, we discuss three parameters of the PCE, number of antenna elements, and path-loss exponent and their effects on capacity of the system via some computer simulations.

Method of closed loop springback compensation for incremental sheet forming process

The closed loop control model was built up for compensating the springback and enhancing the work piece precision.A coupled closed loop algorithm and a finite element method were developed to simulate and correct the springback of incremental sheet forming.A three-dimensional finite element model was established for simulation of springback in incremental sheet forming process.The closed loop algorithm of trajectory profile for the incremental sheet forming based on the wavelet transform combined with fast Fourier transform was constructed.The profile of processing tool path of shallow dishing with spherical surface was designed on the basis of the profile correction algorithm.The result shows that the algorithm can predict an ideal profile of processing track,and the springback error of incremental sheet forming is eliminated effectively.It has good convergence efficiency,and can improve the workpiece dimensional accuracy greatly.

Research on closed-loop simulation system for digital AC servo system

An intelligent and efficient closed-loop simulation system without any hardware is proposed for AC servo system.According to the characteristics of AC servo system and its control processor,the code executing platform combined with the reverse Polish notation algorithm is developed.To gain the accurate simulation results,the discrete motor model and IPM model are built to deal with the dead-time.Based on the simulation system,parameter identification can be implemented and control parameters can be optimized by using the exhaust algorithm.The parameters obtained by the simulation system were successfully applied to an experimental system,and the favorable control performance was achieved.

基于Matlab/Simulimk的直流调速系统虚拟实验教学

在分析闭环调速系统的结构与工作原理的基础上,利用Simulink建立了系统的仿真模型,给出了参数设置,利用仿真结果综合分析、比较了闭环调速系统在不同的转速给定值、不同的放大系数、不同的调节器和有、无电流截止负反馈情况下起动与加载的动态调节过程,并对其调速性能进行了分析与比较。仿真结果验证了调速系统仿真模型的可行性。

双闭环控制的三电平逆变电路Simulink仿真实验

针对开环的三电平逆变电路稳定性差、动态响应慢、带载能力弱等问题,提出了电压、电流双闭环的控制方案。选取二极管箝位式三电平逆变电路作为被控对象,建立其在同步旋转坐标系下的数学模型,分别对电流环和电压环进行设计。电流环包括基于d、q轴的电感电流前馈解耦及PI参数的设计;电压环包括基于d、q轴的电容电压前馈解耦及控制器参数的设计。在Simulink仿真实验平台上,建立了双闭环控制的三电平逆变电路的仿真模型,分析了突变负载情况下双闭环控制的逆变输出电压和电流的仿真波形。

钨极氩弧焊逆变电源系统PI控制的Simulink仿真整定

钨极氩弧焊 (GTAW )逆变电源系统是典型的大信号非线性系统 ,很难用线性化小信号的解析方法进行近似估计 ,作者利用Matlab中具有建模、分析和仿真等多功能的Simulink工具包 ,根据逆变电源的控制结构及GTAW电弧负载的特点 ,建立了由PI调节的GTAW逆变电源 -电弧闭环系统的模型 ,在此基础上 ,进行了Simulink仿真研究 ,并进行了PI参数的调整。研究表明 ,PI调节的比例系数对系统的e动态响应有较大的影响 ,积分系数对消除系统的稳态误差起着较大的作用 ,同时 ,若这两个参数选择不当 。

基于Simulink的普通方向阀控制液压缸位置闭环系统的建模仿真与实验研究

为了降低液压缸位置闭环控制系统的成本,该文将普通方向阀引入到扇形段辊缝液压缸位置闭环调节控制系统中,采用Simulink仿真软件建立了系统的仿真模型,并对该模型进行了仿真分析及现场实验。仿真与实验结果基本一致,证明所建立模型的正确性及参数设置的合理性,为后续的普通方向阀控制位置闭环系统的开发提供了较高的参考价值。

增程式电动拖拉机动力电池供电系统研究

增程式电动拖拉机具有节能减排、续航时间长等优点,但现有动力电池组电压等级较低,无法满足增程式电动拖拉机整机直流母线电压需求。为此,针对增程式电动拖拉机整机500 V电压平台需求,研究了其动力电池供电系统,完成了动力电池供电系统硬件设计和控制设计,最终利用MatLab/Simulink进行了仿真验证。仿真试验方面,所设计的动力电池供电系统实现了从320 V到500 V良好的升压稳压控制与闭环直流电源供电效果,能够适应与增程器等其他电源并联均流供电需求,动力电池供电系统具有良好的动态性能和稳态性能,满足稳定供电需求。

Robust Controller Design for Satellite Attitude Tracking System

The attitude tracking control problem for a satellite with parameter uncertainties and external disturbances is considered in this paper. For this class of multi-input multi-output uncertain nonlinear systems, a design method of robust output tracking controllers is proposed based on the upper-bounds of the uncertainties. Using the input/output feedback linearization approach and Lyapunov method, a control law is designed, which guarantees that the system output exponentially tracks the given desired output. The proposed controller is easy to compute and complement. Simulation results show that, in the closed-loop system, precise attitude control is accomplished in spite of the uncertainties in the system.

基于AMESim与Simulink联合仿真的大吨位液压机主缸速度闭环控制

大吨位液压机主缸在不同运动阶段通常需要不同速度以兼顾压制效率和制品性能,但由于其属于大惯量系统,常规控制方式难以同时满足运动过程的快速性、精确性与平稳性,该文通过改进控制方式以提高此三个特性。首先,分析主缸运动系统的工作原理,建立其数学模型和控制方程;其次,利用AMESim搭建液压系统仿真模型,并通过Simulink创建AMESim仿真模型的控制模块,从而组成闭环控制联合仿真平台,然后通过试验数据验证了仿真模型的准确性。仿真结果显示,采用二次轨迹跟踪指令、变增益以及积分分离相结合的PI控制算法的控制方式比传统的采用阶跃式指令的开环高低速切换控制方法在高低速切换过程的平稳性、速度控制的精确性、压力冲击以及制品的压制效率等性能方面都有较大的提升,其消除了速度突变、下降时间缩短31%、压力冲击减小51.6%,负载干扰下精度提高64%。

Adaptive Robust Control for A Class of Nonlinear Systems with Unknown Uncertainties

The problem of robust stabilization for nonlinear systems with partially known uncertainties is considered in this paper. The required information about uncertainties in the system is merely that the uncertainties are bounded, but the upper bounds are incompletely known. This paper can be viewed as an extension of the work in reference [1]. To compensate the uncertainties, an adaptive robust controller based on Lyapunov method is proposed and the design algorithm is also suggested. Compared with some previous controllers which can only ensure ultimate uniform boundedness of the systems, the controller given in the paper can make sure that the obtained closed-loop system is asymptotically stable in the large. Simulations show that the method presented is available and effective.

基于simulink的模糊自适应PID三闭环控制设计及仿真

针对普通PID三闭环控制容易发生超调、且在负载变化或外加扰动的情况下无法实现对伺服电机精确控制的缺点,本研究提出了将普通PID三闭环控制中的位置环PID控制器用模糊自适应PID控制器替代的模糊自适应PID三闭环控制方法,并在Matlab的Simulink模块中搭建了模糊自适应PID三闭环控制模型,通过施加不同的阶跃信号,发现随着阶跃信号幅值的增加,普通PID三闭环控制调节时间增加,超调量增加,且阶跃信号超过20°时系统发生震荡,而模糊自适应PID三闭环控制调节时间基本不变,超调量为0,在同样的阶跃信号激励下系统不会震荡。通过仿真实验得到模糊自适应PID三闭环控制方法具有超调量小、调节时间稳定、鲁棒性较强的优点。

矿井提升机恒减速制动优化系统Simulink-AMESim联合仿真

针对传统矿井提升机恒减速制动系统存在的精度较低的问题,设计了基于先导式电液比例溢流阀的矿井提升机恒减速制动优化系统,实现滚筒角速度的闭环控制,并对其进行数学建模以及Simulink仿真。之后采用参数模糊自整定PID算法设计模糊控制器,采用AMESim建立液压制动系统的仿真模型。最后进行Simulink-AMESim联合仿真,验证了设计的合理性与优越性。

Multivariable Adaptive Decoupling Controller Using Hierarchical Multiple Models

To solve the problem such as too many models, long computing time and so on, a hierarchical multiple models direct adaptive decoupling controller is designed. It consists of multiple levels. In the upper level, the best model is chosen according to the switching index. Then multiple fixed models are constructed on line to cover the region which the above chosen fixed model lies in.In the last level, one free-running and one re-initialized adaptive model are added to guarantee the stability and improve the transient response. By selection of the weighting polynomial matrix, it not only eliminates the steady output error and places the poles of the closed loop system arbitrarily, but also decouples the system dynamically. At last, for this multiple models switching system, global convergence is obtained under common assumptions. Compared with the conventional multiple models adaptive controller, it reduces the number of the fixed models greatly. If the same number of the fixed models is used, the system transient response and decoupling result are improved. The simulation example illustrates the power of the derived controller.

Design of Type-1 and Interval Type-2 Fuzzy PID Control for Anesthesia Using Genetic Algorithms

This paper presents the automatic drug administration for the regulation of bispectral (BIS) index in the anesthesia process during the clinical surgery by controlling the concentration target of two drugs, namely, propofol and remifentanil. To realize the automatic drug administration, real clinical data are collected for 42 patients for the construction of patients’ models consisting of pharmacokinetic and pharmacodynamic models describing the dynamics reacting to the input drugs. A nominal anesthesia model is obtained by taking the average of 42 patients’ models for the design of control scheme. Three PID controllers are employed, namely linear PID controller, type-1 (T1) fuzzy PID controller and interval type-2 (IT2) fuzzy PID controller, to regulate the BIS index using the nominal patient’s model. The PID gains and membership functions are obtained using genetic algorithm (GA) by minimizing a cost function measuring the control performance. The best trained PID controllers are tested under different scenarios and compared in terms of control performance. Simulation results show that the IT2 fuzzy PID controller offers the best control strategy regulating the BIS index while the T1 fuzzy PID controller comes the second.

基于Simulink/Carsim的轮式移动机器人的联合仿真及其横向稳定性研究

针对轮式移动机器人横向稳定性能较差的问题,搭建Simulink电机模型与车轮转向模型,利用自带的PID闭环控制系统实现实际车速和车轮转角的自由调节,根据Carsim和Simulink的接口参数设置实现轮式移动机器人传动系统模型与电机模型和转向模型的信号传递,进而实现轮式移动机器人Simulink/Carsim联合仿真.双移线试验结果表明,联合仿真下的轮式移动机器人横向稳定性高于传统移动机器人.

基于Matlab/Simulink的光纤电流互感器建模与闭环反馈控制仿真

基于干涉式光学传感原理与闭环反馈控制策略,建立光纤电流互感器的Matlab/Simulink模型,以及反馈相位以阶梯波累加至2π复位的方式施加到相位调制器上的闭环控制方法。在控制算法中引入相位超前校正网络,有效地改善了系统的动态跟踪能力。对测量结果的多点累加取平均输出的方法进行建模,分析其谐波电流采集能力。仿真结果表明,该模型及其辅助网络能准确反映光纤电流互感器的系统特性,对实际的产品开发与优化设计可起到积极作用。

航天器多级自由边界模拟系统姿态平衡协调控制

为了消除天地力学环境不一致对航天器在轨运行精度的影响,需要在地面开展航天器在轨微振动环境模拟试验,因此针对航天器的设施部分和平台部分,在航天器上、下两端建立了自由边界模拟系统和自动控制模块,通过力闭环和位移闭环对航天器重力卸载过程的平衡协调控制算法进行了设计和实施;并通过硬件设施搭建和软件程序编写完成现场试验,验证了控制系统的可行性和稳定性,也为未来航天器地面模拟试验中重力卸载过程控制系统的设计提供技术支撑并积累了工程经验。