VB在平面四连杆机构运动分析中的应用

介绍了基于VB实现对平面四连杆机构进行全面运动分析的方法.通过一种简单有效的方法建立了数学模型,采用计算机模拟技术,能动态演示机构的运动和自动绘制连杆上任意点的轨迹曲线,并能输出各运动构件的位移图、速度图和加速度图.为平面四连杆的运动分析提供了一条简单易行的途径.     

一种机电液系统的模糊变结构模糊控制器

车辆机械式干摩擦离合器及其执行机构具有非线性、时变、变结构特点，此类机电液系统的快速跟踪控制较困难。提出一种变结构模糊控制器，此控制器具有特征识别与处理环节，能够在线调节参数和根据系统特征状态选择合适的控制模式；此控制器带有前馈环节，可以提高系统的快速响应能力。利用此模糊变结构控制器对离合器进行斜坡和二次曲线快速跟踪控制试验，结果表明，此模糊控制器对一类非线性、时变、变结构特点的机电液系统具有一定     

控加工过程的建模与仿真

面向对象技术强调模型的层次化和模块化 ,有利于提高模型的封装性、重用性、可扩展性和可维护性。本文在对仿真对象进行面向对象分析的基础上 ,提出了以装配树为基础 ,采用面向对象技术建立数控加工仿真系统的几何模型和运动模型的新方法 ,统一了运动模型和几何模型 ,解决了数控加工仿真系统中的模型复杂和重用性差的问题     

Direct yaw moment control for distributed drive electric vehicle handling performance improvement

For a distributed drive electric vehicle (DDEV) driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control (DYC) has been widely studied and applied to vehicle stability control. Good vehicle handling performance: quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts: a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error (ITAE) function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method: yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.     

汽车移线轨迹的闭环最速控制模型及仿真

提出了汽车驾驶员移线控制的时间最小模型，该模型是考虑自动操纵汽车时常常采用的达到某一目标所需时间最小的原则，进一步采用闭环反馈开关控制进行轨迹拟合和优化控制，确定出最优轨迹和最优操纵时刻，称为最速控制。采用仿真方法验证了该模型及最速控制理论和方法的正确性，该理论和方法不仅可以作为智能汽车或汽车自动驾驶的控制方法，也可以作为一种驾驶员模型为汽车转向系统的合理设计提出方向。     

整车排放试验污染物瞬态质量测量方法研究

针对整车排放开发试验中直采排放测量设备不能直接测量出污染物瞬态质量的问题,采用了在袋采排放测量系统中增加稀释空气流量计SAO或者示踪CO2分析仪的方法,将袋采和直：采测量设备关联起来,实现了污染物的瞬态质量测量。采用SAO方法时,通过测量混合前稀释空气的瞬态流量,计算出汽车排气的瞬态体积,再用直采系统测出污染物的瞬态体积浓度值就可以换算成汽车排气污染物的瞬态质量值。采用TraceCO2方法时,通过比较稀释管道中混合气的CO2瞬态体积浓度值与稀释前尾气的CO2体积浓度,得出了动态稀释比,从而间接计算出了汽车排气的瞬态体积,进而计算出污染物瞬态质量值。试验结果证明,加装稀释空气流量计SAO和示踪CO2分析仪的排放测量系统,能够有效测量出汽车排气中污染物的瞬态质量值。     

柔性车辆振动和运行平稳性控制研究

通过对铁道车辆柔刚体系统进行动力学分析，应用独立模态空间控制理论，提出了通过控制车体的一阶垂直弯曲模态和车体浮沉、点头刚体振动模态，改善车辆运行平稳性的混合控制策略。在最优控制基础上，采用磁流变阻尼器作为作动器的半主动控制策略，实现能量消耗和控制效果的协调。机械系统和控制系统的联合仿真结果显示：半主动控制策略较好地抑制了车体低阶弹性弯曲振动和车体浮沉刚体振动；车辆运行平稳性性能的改善接近最优控制策略；对车辆系统而言，半主动磁流变阻尼器的实现是可行的。     

Fuzzy Sliding Mode Control for the Vehicle Height and Leveling Adjustment System of an Electronic Air Suspension

The accurate control for the vehicle height and leveling adjustment system of an electronic air suspension(EAS) still is a challenging problem that has not been effectively solved in prior researches. This paper proposes a new adaptive controller to control the vehicle height and to adjust the roll and pitch angles of the vehicle body(leveling control) during the vehicle height adjustment procedures by an EAS system. A nonlinear mechanism model of the full?car vehicle height adjustment system is established to reflect the system dynamic behaviors and to derive the system optimal control law. To deal with the nonlinear characters in the vehicle height and leveling adjustment processes, the nonlinear system model is globally linearized through the state feedback method. On this basis, a fuzzy sliding mode controller(FSMC) is designed to improve the control accuracy of the vehicle height adjustment and to reduce the peak values of the roll and pitch angles of the vehicle body. To verify the effectiveness of the proposed control method more accurately, the full?car EAS system model programmed using AMESim is also given. Then, the co?simulation study of the FSMC performance can be conducted. Finally, actual vehicle tests are performed with a city bus, and the test results illustrate that the vehicle height adjustment performance is effectively guaranteed by the FSMC, and the peak values of the roll and pitch angles of the vehicle body during the vehicle height adjustment procedures are also reduced significantly. This research proposes an effective control methodology for the vehicle height and leveling adjustment system of an EAS, which provides a favorable control performance for the system.     

一种高空作业车液压系统设计与仿真

针对现有高空作业车液压系统功率损失大、支腿和上装动作不能互锁等问题,结合高空作业车液压系统配置,设计一种高空作业车液压系统,采用理论分析和建模仿真相结合的方式进行研究.首先构建液压系统原理图介绍其工作原理;然后利用AMESim仿真软件建立其仿真模型;最后对其工作原理和压力调节特性进行仿真和分析.结果表明:液压系统采用变...     

Micro circular path measurement of two-axis stage using a machine vision system and the application

Usually, verifying the 2D positioning accuracy of a multi-axes stage is not easy. This is because there is little such a device to measure the 2D path directly in micron accuracy. This paper studies on a measuring method for a micro circular 2D path precisely. A machine vision technique is used to trace the moving path of two-axis stage. This method is compared with the ball-bar system, which is commonly using in CNC machine tool companies for inspecting the performance of circular motion movement. However, it is not common to measure a small circular moving path as less than 0.1?mm diameter. The machine vision system is used to trace a target on the two-axis stage moving. To improve the target imaging quality and resolution, a zoom lens is used in this test. The accuracy of this method depends on the CCD resolution and the lens optics. This technique will be useful to trace a small object in the 2D micropath in real time accurately. Also, this method can be one of those that measure the positioning error vector in the working volume of CNC machine tool.     

光电探测系统辅助SINS的动态对准方法

针对陆地战车对定位和定向系统的要求越来越高,提出了一种高精度的对准方法。采用光电探测系统计算出精确的车辆位置和航向,在两次光学定位过程中利用运动约束与零速修正组合的方法估计出惯导系统系统误差,进而估算出光电探测系统与捷联惯导系统之间的敏感轴安装偏角。仿真结果表明:光电探测系统的定向精度优于10″,定位精度优于0.1 m,敏感轴安装偏角的估计精度优于20″,因此本系统满足陆用战车的高精度动态对准需求。     

Real-time accurate odometer velocity estimation aided by accelerometers

In strap-down gyro-compass in-motion alignment, the alignment accuracy depends not only on the quality of the gyroscopes and accelerometers, but also on the accuracy of the velocity provided by the aiding sensors such as odometers. To improve the accuracy of the in-motion alignment, real-time accurate odometer velocity estimation is required. In this paper, the effect of the noise of the odometer velocity on strap-down gyro-compass in-motion alignment accuracy is presented, based on the strap-down gyro-compass algorithm. A velocity tracking model is designed as the state model, to describe the relationship between and among the vehicle’s velocity, acceleration and jerk in the vehicle frame. Based on the velocity equation applied to strap-down navigation system mechanizations, the vehicle’s acceleration in the vehicle frame can be obtained from the specific forces measured by accelerometers. With the observations including the vehicle’s acceleration in the vehicle frame and the vehicle’s velocity in the vehicle frame obtained from the odometer using the first order difference algorithm, real-time velocity estimates are produced by a Kalman filter. The field test results show that the proposed method can successfully improve the accuracy of the odometer velocity. The comparison with the traditional method highlights the superior performance of the proposed method.     

Real-time Tire Parameters Observer for Vehicle Dynamics Stability Control

The performance of the vehicle dynamics stability control system(DSC) is dominated by the accurate estimation of tire forces in real-time.The characteristics of tire forces are determined by tire dynamic states and parameters,which vary in an obviously large scope along with different working conditions.Currently,there have been many methods based on the nonlinear observer to estimate the tire force and dynamic parameters,but they were only used in off-line analysis because of the computation complexity and the dynamics differences of four tires in the steering maneuver conditions were not considered properly.This paper develops a novel algorithm to observe tire parameters in real-time controller for DSC.The algorithm is based on the sensor-fusion technology with the signals of DSC sensors,and the tire parameters are estimated during a set of maneuver courses.The calibrated tire parameters in the control cycle are treated as the elementary states for vehicle dynamics observation,in which the errors between the calculated and the measured vehicle dynamics are used as the correcting factors for the tire parameter observing process.The test process with a given acceleration following a straight line is used to validate the estimation method of the longitudinal stiffness;while the test process with a given steering angle is used to validate the estimated value of the cornering stiffness.The ground test result shows that the proposed algorithm can estimate the tire stiffness accurately with an acceptable computation cost for real-time controller only using DSC sensor signal.The proposed algorithm can be an efficient algorithm for estimating the tire dynamic parameters in vehicle dynamics stability control system,and can be used to improve the robustness of the DSC controller.     

汽车/护栏碰撞试验室张紧系统的设计

通过对汽车/护栏碰撞试验室张紧系统结构的分析,结合实际情况,提出了一种新型的张紧系统设计方法。此种张紧系统既能在空闲期又能在碰撞试验过程中安全地放松和张紧牵引钢丝绳。通过这种设计方法设计完成的长沙理工大学汽车/护栏碰撞试验室的张紧系统,经碰撞试验和突发事故系统应变性检验,能到达预期的张紧效果。     

Robust control of maglev vehicles with multimagnets using separate control techniques

A robust control design scheme using well-developed SISO techniques is proposed for maglev vehicles that are inherently unstable MIMO systems. The proposed seperate control method has basically two control loops: a stabilizing loop by a pole-placement technique, and a performance loop using a novel optimal LQ loop-shaping technique. This paper shows that the coupling terms involved in maglev vehicles with multimagnets should not be neglected but compensated for their stability and performance robustness. The robustness properties of the proposed control system are then evaluated under variations of vehicle masses and air gaps through a computer simulation. This paper also describes the reason why the proposed control technique can be suggested as a tool using only SISO techniques in controlling unstable MIMO systems such as maglev vehicles.     

运动副间隙对汽车摆振系统非线性动力学行为影响分析

在前期研究中发现运动副间隙对机构的动力学响应影响显著,因此做出转向系统中的间隙也会对转向摆振系统的响应产生重要影响的推断。为此,将转向梯形机构简化为一个连杆机构,并就机构中运动副间隙对转向系统摆振的影响进行了分析。借助拉格朗日方程建立考虑转向机构运动副间隙的6自由度转向系统摆振动力学模型,基于该摆振模型,应用四阶龙格－库塔法对间隙参数发生变化时摆振系统的响应进行仿真分析。通过仿真分析结果发现：转向机构运动副间隙是诱发转向轮摆振系统混沌运动的重要因素,在摆振系统建模过程中应予以充分考虑;随着运动副间隙增大,转向摆振系统会由周期运动状态经过拟周期运动状态逐渐进入混沌状态,造成摆振运动加剧。相关结论可为转向系统摆振的有效控制奠定理论基础。     

Test bed for vehicle longitudinal control using chassis dynamometer and virtual reality: An application to adaptive cruise control

In this study, a test bed for vehicle longitudinal control is developed using a chassis dynamometer and real time 3-D graphics. The proposed test bed system consist of a chassis dynamometer on which test vehicle can run longitudinally, a video system that shows virtual driver view, and computer that control the test vehicle and realize the real time 3-D graphics. The purpose of the proposed system is to test vehicle longitudinal control and warning algorithms such as Adaptive Cruise Control (ACC), stop and go systems, and collision warning systems. For acceleration and deceleration situations which only need throttle movements, a vehicle longitudinal spacing control algorithm has been tested on the test bed. The spacing control algorithm has been designed based on sliding mode control and road grade estimation scheme which utilizes the vehicle engine torque map and gear shift information.     

车辆操纵稳定性评价的改进网状图法

为了建立更完善的车辆操纵稳定性评价体系,提出针对国家标准的改进评价法。首先,应用主成分分析法对车辆操纵稳定性评价指标体系进行降维处理,得出10个对操纵稳定性影响最大的评价指标;然后将各指标对操纵稳定性的贡献率确定为指标权重,提出改进网状图法;最后针对某一车型的操纵稳定性指标计分值,分别应用国家标准和改进方法进行评价,评价总得分不相同,改进方法的结果与主观评价结果更接近。该改进评价方法能体现不同指标对操纵稳定性的不同影响程度,能更准确的评价车辆的操纵稳定性。     

矢量场逐次迭代的人-机身体交流控制

为使人和机器人在身体交流中保持运动协调同步,提出了基于矢量场逐次迭代的人-机身体交流智能控制方法。对智能控制方法中具有任意目标轨迹的三维空间矢量场逐次迭代系统进行算法设计,使其输出的关节期望位移信号能与输入的扭矩信号保持同步,且同步强度要达到能实现参数可调的目的;分析了具备不同矢量场的两个逐次迭代系统的相互作用情况;以人和机器人身体交流的典型例子--下肢外骨骼助力机器人为对象,对该智能控制方法进行了应用仿真,并分析了关节扭矩成分对同步运动的影响。仿真结果表明该控制方法有效。     

车载高架式光电探测系统的作战效能评估

为了准确评估车载桅杆型光电探测系统在设计阶段的效能,提出了将与探测系统直接相关的光电分系统、桅杆分系统、载车分系统进行参数综合化来分析系统作战效能的方法。引入模糊综合评估方法,以专家打分为主要评估手段对车载高架式光电探测系统进行基于总体的作战效能评估研究。将该评估方法应用于某车载高架式光电探测系统,对其搜索跟踪与引导能力、系统可用能力、系统生存能力进行了量化评估。上述三项指标的效能评估值分别为79、85和87,而系统总体效能值为82,这与系统的实际效能基本一致,证明了本方法具有一定的科学性,可推广至其他光电类系统的作战效能分析。