基于FPGA的非线性PID控制器设计与实现

Design and Implementation of Nonlinear PID Controller Based on FPGA

行车取力发电技术的核心问题是如何实现液压泵控马达系统输出转速恒定。而由变量泵-定量马达组成的液压变转速泵控马达系统输出转速存在非线性波动现象,为实现其恒转速输出,提出一种以基于转速偏差的指数函数为参数的非线性PID控制算法。该指数函数实质是一种新型、具有自动修正功能的非线性函数,能反映PID控制器各参数的变化规律。利用FPGA完成非线性PID算法的硬件实现,采用"FPGA+SOPC架构"技术设计了泵控马达恒转速输出控制系统。实验结果表明,在系统负载突变工况下,泵控马达系统输出瞬间转速波动量最大为80 r/min,瞬时超调量小于3.5%,调节时间不超过2.8 s,发电参数达到了国家三类发电要求。

The critical problem of driving force generation technology is how to realize the constant output speed of hydraulic variation speed pump-controlled motor system. The output speed of hydraulic variation speed pump-controlled motor system composed of variable displacement pump and constant displacement motor pres- ents nonlinear wave. A nonlinear PID control algorithm whose parameter is an exponential function basing speed deviation and deviation rate, is proposed to realize its constant output speed. In fact, the exponential function is a new nonlinear function with self-correcting, which can reflect the change rule of PID controller pa- rameters. The hardware completion of this algorithm is accomplished based on FPGA and the constant speed output control system of pump-controlled motor is designed by ＂FPGA ＋ SOPC＂. Experiment results demon- strate that the largest speed fluctuation of pump-controlled motor system is 80 r/min, the largest response time of system is no more than 2. 8 s, the instantaneous overshoot stable with load mutation. These indexes satisfy the III type is less than 3.5 %, and the control performance is of state power generation requirement.