CAJ | 학술논문

为了实现无级调速拖拉机工作时的速比调节与动力换段,该文对其液压机械无级变速器的速比控制进行了研究.根据变速器的速比特性和液压系统辨识试验,确定了变量泵励磁电流、泵-马达速比与变速器速比三者之间的稳态和动态数学模型.基于该模型,设计了基于单神经元网络的神经PID控制器,在Matlab/Simulink下研究了其参数整定规律,得到了一组可行参数并通过了试验验证;在此基础上提出了开环与闭环相结合的继电控制模式,使神经PID控制器工作于特定的区间和条件之下,有效避免了频繁的换段和马达换向问题;并通过台架试验证实了该算法的正确性及可行性.试验中,每个偏向的开环调节时间为5~6 s,调速过程平稳、无静差,变速器能在包含换段点在内的任意速比条件下可靠运行.该研究可为变速器的后续设计及动力匹配提供参考.
위료실현무급조속타랍궤공작시적속비조절여동력환단,해문대기액압궤계무급변속기적속비공제진행료연구.근거변속기적속비특성화액압계통변식시험,학정료변량빙려자전류、빙-마체속비여변속기속비삼자지간적은태화동태수학모형.기우해모형,설계료기우단신경원망락적신경PID공제기,재Matlab/Simulink하연구료기삼수정정규률,득도료일조가행삼수병통과료시험험증;재차기출상제출료개배여폐배상결합적계전공제모식,사신경PID공제기공작우특정적구간화조건지하,유효피면료빈번적환단화마체환향문제;병통과태가시험증실료해산법적정학성급가행성.시험중,매개편향적개배조절시간위5~6 s,조속과정평은、무정차,변속기능재포함환단점재내적임의속비조건하가고운행.해연구가위변속기적후속설계급동력필배제공삼고.
@@@@This paper studied the speed ratio control problem of the hydraulic mechanical continuously variable transmission. First, based on the speed ratio characteristics of the transmission and the experiment on the identification of the hydraulic system, the steady-state and dynamic mathematical model among the excitation current of the variable displacement pump, the speed ratio of the pump-motor system and the speed ratio of the transmission were built. It showed that the speed ratio of the transmission is a segmented function of the speed ratio of pump-motor system. The relationship between the excitation current of the variable displacement pump and the speed ratio of pump-motor can be considered as a third-order system. According to this model, a neural PID controller based on single neuron network was developed. A set of feasible parameters, i.e. the inertia coeffecient k and the learning coeffecient ηP, ηI, ηD of the PID controller can be determined according to the tuning law which have been studied based on the simulation and experiment. From that, it showed that an appropriate k,ηP, a largerηI and a smallerηD can meet a satisfactory internal-stage control quality. Secondly, the open-loop and closed-loop control mode defined by a relay logic was proposed in this paper, so as to make the neural PID controller work at specific intervals and conditions and effectively avoid the frequently power-shift and direction-changed of motor rotation. The controller calculates the target stage and direction of motor rotation according to the target speed ratio of transmission. Once the current stage and direction of motor rotation are different from the target, the power-shift logic and the displacement adjustment logic of the pump can be actived by the open-loop controller to reach the target states following the stepless speed changing rule, otherwise, the closed-loop controller would adjust the speed ratio of the transmission to the target without power-shift and direction-changed of motor rotation based on the neural PID technology. Finally, an experiment of speed ratio control was conducted. During the experiment, it took 5-6 s to hold one direction of motor rotation when the open-loop controller worked, the process under the speed ratio control was smooth and steady and no steady-state error was there at the end of the experiment, the results proved the algorithm to be correct and feasible.