Strategy to control crawling vehicles with automated mechanical transmission

In order to move vehicles with automated mechanical transmission （AMT） a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dynamic analysis of vehicle starting process and requirements of crawl driv- ing for the vehicle, a control strategy of the clutch was designed. The strategy increased the.slipping friction torque first and then decreased it, in order to realize the crawl driving. The speed increased by the engagement of the clutch, and then the clutch turned to disengage to the half disengage point, when the speed met the requirements. Based on the control strategy, a control software was de- signed. In the end, the software was tested on a vehicle with AMT. The lowest steady vehicle speed was reduced to 40% of the original value, which was set in the control strategy.

Slow driving control of tracked vehicles with automated mechanical transmission based on fuzzy logic

In order to move tracked vehicles at an extremely slowspeed with automated mechanical transmission（ AMT）,slowdriving function was added in the original system. The principle and requirement of slowdriving function were analyzed. Based on analysis of slow driving characteristic,identification of slowdriving condition and fuzzy control algorithm,a control strategy of the clutch was designed. In order to realize slowdriving,the clutch was controlled in a slipping mode as manual driving. The vehicle speed was increased to a required speed and kept in a small range by engaging or disengaging the clutch to the approximate half engagement point. Based on the control strategy,a control software was designed and tested on a tracked vehicle with AMT. The test results showthat the control of the clutch with the slowdriving function was smoother than that with original systemand the vehicle speed was slower and steadier.

Shifting force control of an AMT heavy-duty truck based on manual shift test

Taking a heavy-duty truck as a research platform,the changing characteristics of shifting force,shift time,and slipping work are obtained through theoretical analysis and manual shift test of a real vehicle. Based on the analysis of the test results,a gear-shifting control strategy of the hydraulic automated shift control system is designed and experimentally verified on the bench. By optimizing the control parameters of high-speed switching valves,a control strategy and parameters are obtained,which can meet the requirements of dynamic performance and reliability.

Design of hydraulic shift mechanism for AMT vehicles based on the collaborative optimization method

Based on multidisciplinary design optimization（MDO）,a new design method is put forward for hydraulic shift mechanism of heavy-duty vehicle automated manual transmission（AMT）.Taking a shift cylinder for example,the collaborative optimization（CO）method for the design problem of a cylinder is devided into one system level design optimization problem and three subsystem level design optimization problems.The system level is an economic model and the subsystem level is mechanics,kinetics,and a reliability model.Application of the multidisciplinary design optimization software iSIGHT modeling and solving,optimal solution of the shifting cylinder CO model is obtained.According to the optimal solution,oil cylinders are machined out and installed on the gearbox of an AMT system for the bench cycle shift test.The results show that the output force and action speed of the optimized mechanism can meet requirements very well.In addition,the optimized mechanism has a better performance compared to the structure of the traditional design method,which indicates that the CO method can optimize the design of hydraulic transmission.

Coordinated shift control of nonsynchronizer transmission for electric vehicles based on dynamic tooth alignment

Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult challenge because gear shifting may cause discomfort to the occupants.To improve the swiftness of gear shifting,this paper proposes a coordinated shift control method based on the dynamic tooth alignment(DTA)algorithm for nonsynchronizer automated mechanical transmissions(NSAMTs)of EVs.After the speed difference between the sleeve(SL)and target dog gear is reduced to a certain value by speed synchronization,angle synchronization is adopted to synchronize the SL quickly to the target tooth slofs angular position predicted by the DTA.A two-speed planetary NS AMT is taken as an example to carry out comparative simulations and bench experiments.Results show that gear shifting duration and maximum jerk are reduced under the shift control with the proposed method,which proves the effectiveness of the proposed coordinated shift control method with DTA.

AMT车辆纵向期望速度控制方法

为提高AMT(Automated Mechanical Transmission)车辆纵向期望速度控制的快速性及适应性,提出一种基于油门、挡位的2参数纵向期望速度控制方法。首先根据车辆动力学模型进行广义地面阻力系数求解,建立了换挡查表模型,然后对用于油门控制的模糊PID控制器进行设计,并以某型配备AMT变速箱的履带车辆为研究对象建立仿真模型,通过仿真实验对所提出的纵向期望速度控制方法进行验证,以换挡决策时间、纵向期望速度控制响应时间和车辆行驶距离为评价指标对该方法进行评价。仿真结果表明:所提出方法对于纵向期望速度指令及路面情况变化可迅速做出换挡决策,可以满足速度控制快速性及适应性要求。