STATIC CORRECTION MODES IN DYNAMICAL SIMULATION OF FLEXIBLE MULTIBODY SYSTEM WITH CLOSED LOOPS

By use of the recursive formulation of flexible multibody system with closed loops,this paper studies the dynamic simulation of complicated multibody system.The conception of static correction modes in structural dynamics is introduced to present the local deformation effects due to reaction forces at kinematic joints.A space four bar mechanism is utilized here as an example to describe the method of selecting static correction modes.Compared with vibration normal modes, static correction modes are demonstrated to be effective in numerical simulation.

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.

Open-plus-closed-loop control for chaotic motion of 3D rigid pendulum

An open-plus-closed-loop （OPCL） control problem for the chaotic motion of a 3D rigid pendulum subjected to a constant gravitationM force is studied. The 3D rigid pendulum is assumed to be consist of a rigid body supported by a fixed and frictionless pivot with three rotational degrees. In order to avoid the singular phenomenon of Euler＇s angular velocity equation, the quaternion kinematic equation is used to describe the motion of the 3D rigid pendulum. An OPCL controller for chaotic motion of a 3D rigid pendulum at equilibrium position is designed. This OPCL controller contains two parts： the open-loop part to construct an ideal trajectory and the closed-loop part to stabilize the 3D rigid pendulum. Simulation results show that the controller is effective and efficient.

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.

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.

A Hybrid Simulation Test Platform for Verifying the Protection Settings of SPS

To verify the effectiveness and correctness of the protection settings in ring structure Shipboard Power System (SPS), a digital-physical hybrid simulation platform at China Ship Development and Design Center (CSDDC) has been built, which aims to give double verification effect of design scheme and physical device. The platform consists of eMEGAsim digital simulator, signal power amplifiers and digital-analog interface equipments. With this platform, the multiple protection device of ring structure grid can be accessed to form a close-loop test system. Since eMEGAsim model-simulated faults and actual protection device actions are on real time, the tripping settings of each device as well as their coordinate performance between multiple devices can be verified in this close-loop test.

A general method for closed-loop inverse simulation of helicopter maneuver flight

Maneuverability is a key factor to determine whether a helicopter could finish certain flight missions successfully or not. Inverse simulation is commonly used to calculate the pilot controls of a helicopter to complete a certain kind of maneuver flight and to assess its maneuverability.A general method for inverse simulation of maneuver flight for helicopters with the flight control system online is developed in this paper. A general mathematical describing function is established to provide mathematical descriptions of different kinds of maneuvers. A comprehensive control solver based on the optimal linear quadratic regulator theory is developed to calculate the pilot controls of different maneuvers. The coupling problem between pilot controls and flight control system outputs is well solved by taking the flight control system model into the control solver. Inverse simulation of three different kinds of maneuvers with different agility requirements defined in the ADS-33 E-PRF is implemented based on the developed method for a UH-60 helicopter. The results show that the method developed in this paper can solve the closed-loop inverse simulation problem of helicopter maneuver flight with high reliability as well as efficiency.

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.

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。

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。

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。

基于MATLAB/Simulink的双闭环SPWM变频调速系统仿真

设计了转速、电流双闭环的变频调速控制系统。利用MATLAB/Simulink仿真软件,搭建了三相异步电机转速、电流双闭环SPWM变频调速系统。通过调节各模块的设置参数,得到了理想的仿真波形,实现了该系统的仿真。通过将仿真结果与开环变频电路仿真结果相比较可以看出,闭环变频调速系统在调速能力和抵抗负载扰动等方面比开环系统有更好的动态特性,并且有较宽的调速范围。说明了双闭环调速SPWM变频调速系统良好的调速特性。

Simulink与电路网络的混合仿真

为实现Simulink与电路网络的混合仿真,将被控对象的数学模型转换成电路网络,然后用Powerlib工具箱实现该电路。针对被控对象设计其基于闭环增益成形算法的PID控制器,用Simulink工具箱实现该控制器,通过可控电压源实现Simulink与电路网络的混合仿真。实例仿真结果表明本方法可行,为进一步实现计算机与电路网络的半物理仿真打下基础。

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。

开环轨迹无碳小车设计与误差分析

为实现无碳小车开环轨迹运动,设计并制作了一种基于凸轮机构的无碳小车,可以通过更换凸轮实现不同开环轨迹的运动。首先,结合小车功能要求,设计出小车的整体结构和基本参数,其次,根据已知坐标点利用贝塞尔曲线对理论轨迹进行拟合,获得前轮转角曲线及推程曲线并将其极坐标化得到理论凸轮轮廓,经凸轮原理分析,对凸轮轮廓包络处理,获得实际凸轮轮廓曲线。最后,根据小车实际运行轨迹在MATLAB中进行参数反推仿真,模拟误差产生方式,得出最优调整方案。结果表明,凸轮基圆直径和转向偏距对开环运动轨迹均有影响,其中,凸轮基圆直径对整体运动轨迹影响较大,可作为整体轨迹修正参数;转向偏距对中后程运动轨迹产生旋转偏移,可作为局部轨迹修正参数。文中所述模型及对轨迹误差的研究具有普适性,对开环轨迹小车调试具有较高的指导意义。

基于Matlab/Simulink的伺服系统仿真

在Matlab/Simulink环境下,设计和组合了交流同步伺服电机、dq坐标系向abc坐标系转换、三相电源逆变器、位置调节器、速度调节器和电流调节器各模块,并在此基础上构建了交流同步伺服系统的位置、速度和电流3闭环仿真模型。仿真结果证明了该控制方法的有效性,为交流同步伺服系统的设计提供了理论依据。

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%。