四轮驱动汽车电动助力转向控制研究

为了研究四轮驱动汽车的电动助力转向控制,建立电动助力转向系统动力学模型,提出基于模糊PID控制的电动助力转向控制策略。借助离线仿真的技术,对控制策略的有效性加以论证,得出四轮驱动汽车电动助力转向控制的最佳系统功能提升方案。     

基于模糊控制的电动助力转向系统控制方法研究

基于模糊控制的基本原理及模糊控制器的设计方法,对模糊＂PID参数整定的方法进行研究。针对电动助力转向系统,设计了一种模糊自整定PID参数控制策略,利用MATLAB软件对控制算法进行仿真。通过仿真实验,证明了所设计的电动助力转向系统控制算法将PID控制和模糊控制的简便性、灵活性以及鲁棒性相结合,提高了电动助力转向系统的助力控制性能。     

汽车电动助力转向的机电耦合系统开发

为满足微型纯电动汽车转向轻便和高速稳定行驶的性能需求,进行了转向系统的电动助力设计优化。综合考虑转向系统几何结构、电机助力参量等因素的影响,实现了电动助力系统参数化并建立了机电耦合数学模型。构建考虑车速影响的助力特性曲线并对函数精确度进行控制,提高拟合准确度,确定电机力矩控制特性。电动助力系统应用基于模糊自适应PID控制策略,控制电机电流误差,减少电流偏差,提高辅助力的精准度。利用建立的机电耦合数学模型、电机转矩控制特性和PID控制策略,在MATLAB/Simulink和ADAMS/CAR中构建机械与助力电机控制模型,进行联合仿真,与非助力系统进行对比分析了连续转向、高速行驶转向和大角加速度转向3种行驶工况的仿真结果,结果表明:电动助力系统在中低速蛇形行驶中,减轻约48%转向力矩,有效实现汽车的转向轻便,在高速行驶转向中缩短了车辆达到高速稳定行驶约20%的时间。     

电动助力转向系统双闭环模糊PID控制系统分析

电动助力转向系统(EPS)是机电结合的控制系统,电流PID控制是以目标电流和反馈电流为差值的闭环控制系统,模糊控制是以机械转向轴取差值的机电闭环控制系统,本文以力矩反馈环为外环,电流反馈环为内环,设计了一个双闭环控制系统.将模糊PD控制的输出作为助力目标值,然后进行电流PID控制,快速跟踪目标力矩. 经仿真模拟,双闭环模糊PID控制使电动助力转向系统具有更好的跟踪性和稳定性.     

混合动力客车电动助力转向系统设计与仿真研究

开发了适合混合动力大客车的电动助力转向系统,进行了系统助力特性的匹配设计。在分析该系统各组成部分数学模型的基础上,建立了基于MATLAB/Simulink软件的客车电动助力转向系统的仿真模型。采用PID控制和脉宽调制(PWM)直流斩波技术对助力电动机的助力电流进行闭环跟踪控制。仿真结果表明,所建模型及采用的控制方法有效,助力电流跟踪效果良好,助力转向响应快,满足助力特性及系统对路感的要求,设计的助力特性有效。     

电动助力转向系统建模及动力学仿真分析

通过汽车电动助力转向系统(EPS)的结构及其动力特性分析,建立其数学模型,针对其本身是一个比较复杂的非线性随动系统,采用模糊控制理论,设计一种自适应模糊PD控制系统,并进行仿真研究.仿真结果表明,基于模糊PD控制的电动助力转向系统比传统PD控制具有更好的助力特性和抗干扰能力.     

EPS助力系统模糊PID控制器的设计

设计了电动助力转向助力系统的模糊PID控制器,并对其控制系统进行仿真分析,仿真表明控制器不但保证了电动助力转向系统良好的响应特性还能有效地抑制共振峰.     

基于模糊控制的汽车助力转向系统设计

设计了一种ARM单片机控制的汽车电动助力转向系统,采用模糊自调整PD控制策略建立了电动助力转向系统的数学模型;设计了模糊控制器,对电动助力转向系统进行闭环控制仿真试验,结果表明系统性能稳定,提高了汽车转向轻便性和行驶安全性。     

基于PID控制优化电动助力转向系统研究及仿真

通过对电动助力转向系统结构及工作原理的分析,完善了基于PID控制的电动助力转向系统动力学模型,提出转矩信息和基于PID控制策略的电机控制信息的融合方法,解决了在控制过程中系统内部信息融合和优化问题,提高了电动助力转向系统的安全性和稳定性。并采用MATLAB进行了模型仿真,初步获得了较好的仿真效果。仿真结果表明,基于该模型的控制策略,在不同的车速情况下有效的改善了方向盘转矩输出,增加了转向过程中的灵巧性和实时性。     

电动助力转向控制系统的研究与仿真分析

作为车辆动力转向的新技术,电动助力转向系统已经获得了较广泛的应用。助力控制是转向系统的基本控制策略并决定转向系统的助力性能。以电动助力转向系统的跟踪性和稳定性为控制系统设计目标,应用专家PID原理对电动助力转向控制系统进行开发研究,并结合虚拟样机技术对控制系统进行仿真分析。仿真结果证实,所设计的专家PID控制算法使电动助力转向系统具有良好的跟踪性和稳定性。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.