液压机械无级变速器的变参数PID控制

VARIABLE PARAMETER PID CONTROLON THE HYDRO-MECHANICALSTEPLESS TRANSMISSION

针对液压机械无级传动的特点,设计了带死区、积分饱和抑制的增量式变参数PID算法的控制器。利用BP神经网络对PID控制算法的三个参数进行在线整定,通过理论与试验结合的方法,确定了BP神经网络的中间隐层节点数和带惯性项最速下降算法的学习速率和惯性系数。台架试验结果表明,在转速调节方案下,变参数PID控制器能使驱动装置的输出功率基本恒定,即变参数PID控制器能通过改变液压机械无级变速器传动比的方法使发动机稳定工作在最佳动力性或者最佳经济性曲线上。

A dead-section and integral saturation restrain PID controller is designed according to the character of the hy-dro-mechanical transmission. BP neural net is used to adjust the three parameters of the PID control arithmetic using the most-rapid descending arithmetic with a inertia item. The num-ber of medial node in the BP neural net, the study rate and iner-tia coefficient in the most-rapid descending arithmetic are de-termined by theoretical analysis and tests respectively. The results of the tests in the lab show that the PID controller can make the output of the driving unit be constant under speed adjusted. That means the PID controller can make the engine work in the most powerful or the most economical mode by adjusting the ratio of the hydro-mechanical transmission if that is used in the automobiles.