Energy efficient electromagnetic actuated CVT system

A continuously variable transmission (CVT) system transmits the engine/battery power to the car driving wheel smoothly and efficiently. Several types of CVT already been developed to improve the transmission losses while maintaining acceleration time. However, most of the CVT has some constraints in the actuation mechanism which led us to develop an innovative electromagnetic actuator for CVT. Simplified mathematical equations have been developed for the kinematics analysis of clamping forces of the CVT and electromagnetic forces of EMA. The EMA has been developed for ¼ scale car with two sets of solenoid. Each of the two sets has been equipped with primary and secondary pulleys for pushing and pulling the movable sheave. The solenoid is operated by controlling the supply current with a fuzzy logic controller. A simulation based fuzzy logic controller has been introduced here for identifying the desired current of the EMA actuation. The experimental results show that the EMA develops electromagnetic forces 301 N for the supply current of 3.37 amp, which makes the acceleration time of the car in the range of 2.5～3.5 sec and electromagnetic actuated CVT system highly energy efficient.     

Integrated control strategy for CVT powertrains with consideration of vehicle drivability

During shift,power flow is not interrupted in powertrains equipped with continuously variable transmission(CVT).When hard acceleration is commanded,engine speed will flare and corresponding torque will be consumed,which leads to a drop in vehicle drive torque and also the vehicle acceleration.This is the reason why CVT vehicles have poor drivability during hard acceleration maneuver.Conventional method such as torque compensation doesn’t always work due to the limited backup torque of engine.According to this,means to evaluate the drivability of CVT vehicles are studied,affect factors of drivability are analyzed in detail.Hard acceleration process of CVT vehicle is studied by theoretical analysis,based on which engine torque and ratio change rate of CVT are identified as two key control parameters that decide the drivability of CVT vehicles during hard acceleration maneuver.Therefore,a control strategy based on restricting the change rate of CVT ratio together with torque compensation is proposed,and two different algorithms to establish the limitation of ratio change rate are proposed.These two algorithms are simulated and compared with each other,results indicate that drop of vehicle acceleration is eliminated evidently by limit the change rate of CVT ratio,but small ratio change rate also results in a longer time to finish the accelerate process,an algorithm to decide a proper ratio change rate is needed in order to tune these different characteristics.In order to get better control effects,a new fuzzy logic based algorithm is proposed to decide a proper ratio change rate during kick down conditions,simulation and experiment results indicate that,the amount of vehicle acceleration decrease is reduced from about 1 m/s2 to almost 0,in the mean time the accelerate process only delayed for about 0.3 s.The proposed control strategy and algorithm can effectively tune the characteristics of CVT equipped vehicle during kick down conditions.     

机动车乘员约束系统的仿真建模分析

本文应用Madymo软件,以多刚体和有限元理论为基础,探讨了建立机动车乘员约束系统仿真模型的方法.为成员约束系统的整车匹配提供了良好的研究手段和仿真实验方法.     

汽车非线性悬架最优控制的研究

建立了车辆两自由度非线性动力学模型及包含悬架刚度立方非线性的运动微分方程,运用Runge-Kutta方法求出了被动悬架与半主动悬架系统对水泥路面、搓板路面、卵石路、鱼鳞坑路4种路谱的响应,采用模拟计算法得出车身竖直振动加速度的均方根值,并将被动悬架与半主动悬架系统的响应进行比较,在振动舒适度改进的同时,悬架弹簧的变形量增大,因此应该合理选择系统参数为汽车的动态设计提供了理论依据.     

Flow analysis of engine cooling system for a passenger vehicle

A numerical simulation is carried out to analyze the flow field of cooling air through the radiator and engine compartment. In order to consider the strong effect of the suction-type flow by the cooling fan at engine idling condition, a potential flow analysis is attempted by the assumption of a line sink located at the position of the cooling fan. The governing equations for steady two-dimensional, incompressible, turbulent flow are solved with the two-equationk-ε model for turbulence. The velocity profiles in the underhood engine compartment and around the front-end of a real vehicle are measured to compare with the numerical results. The agreement between the numerical and experimental results is fairly good. It is concluded that a two-dimensional computation is a fast and efficient tool for predicting the effect of front-end design on the cooling air flow through the radiator.     

CVT湿式离合器液压控制系统设计

根据无级变速器液压控制系统要求,对液压控制系统的结构进行了设计.为了进一步提高液压控制系统的控制性能,在高速开关电磁阀驱动中使用了多路混合驱动方法.设计的液压控制系统能够在工作范围内自动调节液压系统的压力,同时具有良好的控制特性,进一步提高CVT湿式离合器的工作性能.     

双源双视角安检装置的控制系统设计

中国原子能科学研究院开展的双源双视角乘用车辆检查装置的研发项目,能够有效提高图像分辨率,提高检测的准确性,避免误报率.为实现双源双视角乘用车安检设备各部分平稳、高效率的工作,设计了一套完整的的安检控制系统.依据车辆安检装置各部分的工作特点、原理及控制要求,从对射线探测的整个流程及对源罐的控制给出了控制系统的方案,介绍了...     

Simulation and control of an electro-hydraulic actuated clutch

The basic function of any type of automotive transmission is to transfer the engine torque to the vehicle with the desired ratio smoothly and efficiently and the most common control devices inside the transmission are clutches and hydraulic pistons. The automatic control of the clutch engagement plays a crucial role in Automatic Manual Transmission (AMT) vehicles, being seen as an increasingly important enabling technology for the automotive industry. It has a major role in automatic gear shifting and traction control for improved safety, drivability and comfort and, at the same time, for fuel economy. In this paper, a model for a wet clutch actuated by an electro-hydraulic valve used by Volkswagen for automatic transmissions is presented. Starting from the developed model, a simulator was implemented in Matlab/Simulink and the model was validated against data obtained from a test-bench provided by Continental Automotive Romania, which includes the Volkswagen wet clutch actuated by the electro-hydraulic valve. Then, a predictive control strategy is applied to the model of the electro-hydraulic actuated clutch with the aims of controlling the clutch piston displacement and decreasing the influence of the network-induced delays on the control performances. The simulation results obtained with the proposed method are compared with the ones obtained with different networked controllers and it is shown that the strategy proposed in this paper can indeed improve the performances of the control system.     

Cushion pressure control system for an intelligent air-cushion track vehicle

This paper presents the control system of cushion pressure for the developed intelligent air-cushion track vehicle (IACTV) for operating on swamp terrain and wet fields. A novel auto-adjusting supporting system is designed for the vehicle’s intelligent air-cushion system. Focusing on minimizing the total power demand of the vehicle, an optimization model has been established, for examining the effects of vehicle parameters and load distribution on power consumption by controlling air-cushion pressure. Then optimum cushion pressure is determined based on the developed optimum pressure — sinkage relationship and the pressure in the cushion chamber is controlled by the Fuzzy controller by maintaining volume flow rate and continuously monitored by the pressure sensor attached with the cushion chamber. The ultrasonic displacement sensor is used to measure the sinkage of the vehicle. The output voltages of the ultrasonic displacement are used to operate the pull-in solenoid switch through the microcontroller which closes the circuit of the compressor motor. Distribution of vehicle load to the air-cushion system is controlled by Fuzzy Logic controller by maintaining the inside pressure of the cushion.     

Heading tracking control with an adaptive hybrid control for under actuated underwater glider

The underwater glider changes its direction to follow the preset path in the horizontal plane only by flapping its vertical rudder. Heading tracking control plays the core role in the navigation process. To deal with non-linear flow disturbance and saturation in actuator, a new hybrid heading tracking control algorithm was presented, which integrated an adaptive fuzzy incremental PID (AFIPID) and an anti-windup (AW) compensator to improve the adaptability and robustness of underwater glider's heading control. The dynamic model of an underwater glider named as Petrel-II 200 was modeled to serve as a controlled plant. The proposed heading tracking control algorithm was described in detail, where the rudder angle, a control quantum to the controlled plant were calculated to get forces and moments required for the desired glider heading. A closed loop motion control system with desired heading angle as input and actual heading angle output was put forward, which included the dynamic model of the Petrel-II 200 and the given heading tracking control algorithm. The simulations followed three typical mathematical signals and the experimental tests were carried out by taking in the dynamic parameters of the controlled plant. And the effectiveness of the proposed control algorithm was assessed and verified.     

Virtual prototyping simulation for a passenger vehicle

The primary goal of virtual prototyping is to eliminate the need for fabricating physical prototypes, and to reduce cost and time for developing new products. A virtual prototyping seeks to create a virtual environment where the development of a new model can be flexible as well as rapid, and experiments can be carried out effectively concerning kinematics, dynamics, and control aspects of the model. This paper addresses the virtual environment used for virtual prototyping of a passenger vehicle. It has been developed using the dVISE environment model including features, functions, and behaviors is constructed by employing an object-oriented paradigm and contains detailed information about a real-size vehicle. The human model is also implemented not only for visual and reach evaluations of the developed vehicle model, but also for behavioral visualization during a crash test. For the real time driving simulation, a neural network model is incorporated into the virtual environment. The cases of passing bumps with a vehicle are discussed in order to demonstrate the applicability of a set of developed models.     

基于SIMULINK的Zero-Max型无级变速器运动学仿真

利用SIMULINK仿真工具,对Zero-Max型脉动式无级变速器机构运动学仿真的方法与过程进行了研究.在建立其运动学数学模型基础上,根据SIMULINK的特点构建了运动学仿真模型,通过实时仿真得到了无级变速器中各杆件的位置、速度与加速度变化规律曲线,并进一步对其运动特性进行了分析研究.实例仿真结果表明,该方法简便、直观、可靠、通用性好,适用于复杂机构的运动学仿真.     

电液式无级变速器速比最优控制系统设计

针对传统电液式CVT速比控制系统存在的结构复杂、可靠性低等缺点,设计了CVT速比最优控制系统。采用PWM高速开关数字阀代替传统比例阀,建立了考虑电磁特性的PWM开关阀数学模型。简化CVT速比液压系统,建立了PWM阀控缸数学模型。应用离散系统二次型最优控制理论优化控制参数,设计了最优控制器。在Matlab环境下进行了起步加速、减速工况的CVT速比控制仿真试验。试验结果表明,所设计的CVT速比最优控制系统的稳态特性和动态特性良好,能够保证实际速比对目标速比的有效跟踪。     

Estimation of turbine torque using an adaptive nonlinear observer for closed-loop control of vehicle automatic transmissions

This paper presents an adaptive sliding observer-based method for the estimation of turbine torque. The estimations of turbine torque can be used in the closed-loop control of vehicle power train for better shift quality. A sliding observer structure including saturation functions and boundary layers is applied to adapt torque converter parameters. The proposed method has been investigated via simulation and laboratory experimental studies. It has been shown via simulation and experiments that the proposed methodology is promising for the estimations of turbine torque since it uses only inexpensive angular velocity measurements and is not sensitive to parametric uncertainties.     

Modeling and control of an electronic-vacuum booster for vehicle cruise control

A mathematical model and control laws for an Electronic-Vacuum Booster (EVB) For application to vehicle cruise control will be presented. Also this paper includes performance test result of EVB and vehicle cruise control experiments. The pressure difference between the vacuum chamber and the apply chamber is controlled by a PWM-solenoid-valve. Since the pressure at the vacuum chamber is identical to that of the engine intake manifold, the output of the electronic-vacuum booster is sensitive to engine speed. The performance characteristics of the electronic-vacuum booster have been investigated via computer simulations and vehicle tests. The mathematical model of the electronic-vacuum booster developed in this study and a two-state dynamic engine model have been used in the simulations. It has been shown by simulations and vehicle tests that the EVB-cruise control system can provide a vehicle with good distance control performance in both high speed and low speed stop and go driving situations.     

四足机器人运动学分析及步态研究

在对典型哺乳动物机体结构分析基础上,提出一种液压驱动四足机器人的简化结构,完成机器人腿部结构的设计,并对腿部机构进行正逆运动学求解,研究不同负载因子下的直行起步调整到稳定行走步态并计算稳定裕度。结果表明:两种步态均能实现稳定的起步和周期行走,其中非连续调整步态的平均稳定裕度较大。     

一种车流量自适应交通灯控制系统的实现

介绍了一种基于555定时器和74LS161计数器的流量自适应交通灯控制系统。该系统采用车流量检测电路实现交通灯亮灭持续时间的自适应控制,较好地解决了当前多数交通灯控制系统存在的不能根据道路上车流量的情况自适应调节的缺点。该系统经组装、调试,并在路口试验。效果良好。     

车用后栏板起重装置的运动学分析

采用复数向量法建立了车用起重尾板起重装置运动学的数学模型,分析了该举升机构运动的特点。采用MATLAB编制了相应的程序,并以实例进行了分析和计算。     

我国客运索道电控系统现状及展望

索道的电气控制系统集中体现了索道的复杂程度和技术水平。介绍了目前我国客运索道应用的不同形式的控制系统,分析了其特点以及对安全性的影响,并对我国客运索道电气控制系统的发展方向进行了展望。     

Slip control strategy for an automatic transmission vehicle

Modern automatic transmissions equip torque converters with lock-up clutches to reduce the energy loss of hydraulic systems. Instead of simply engaging the clutch disks, the new technology of clutch slip has been developed to improve the overall efficiency of power transmission. There are two major problems with the clutch slip system. The first is how to keep the slip between the two disks within a small range and the second is when to start or stop the slip. In this paper, the second problem is discussed in view of the vehicle economy. With a simple vehicle dynamic model, the fuel economy is calculated to determine the lock-up strategy. Then the lock-up strategy is developed for a slip schedule.