果园管道喷雾系统药液压力的自整定模糊PID控制

果园管道喷药系统具有非线性、大时滞特性，且管道中药液的压力随喷嘴数目变化而波动。为此，对管道中药液压力采用了带变速积分、微分先行优化算子的自整定模糊PID控制。根据管道中压力的实际值与设定值间的误差及误差变化趋势，在线调整模糊PID的参数，经带有变速积分、微分先行优化算子的增量式PID算法计算，获得控制量以控制管道中药液的压力。试验结果表明：采用这种控制方法，与不使用自整定模糊PID参数的变速积分、微分先行PID控制相比，管道中压力响应的上升时间缩短18.42%，调整时间缩短12.56%，最大超调量减小4.43%，误差减小50%。该控制方法能满足果园管道喷雾系统中对压力控制的要求。

Self-adjustable fuzzy PID control for solution pressure of pipeline spray system in orchard

Orchard pipeline spraying system has the characteristics of non-linear, apparent delay and a fluctuating pipeline solution pressure along with the changes of nozzle amount. For solving this problem, a self-adjustable fuzzy PID control strategy with differential preceding and gearshift integral was applied on the pipeline solution pressure control. Based on the difference between current pressure and target value, as well as the difference trend, controlling parameters for pipeline solution pressure control were achieved by adjusting the fuzzy PID parameters online and calculating the control variables with the PID algorithm of gearshift integral and differential preceding. Experimental results indicated that, compared with other strategies without the fuzzy PID algorithm, the responding time for pressure rise and adjustment were shortened by 18.42% and 12.56% respectively. The maximum overshoots and system error were reduced by 4.43% and 50% respectively. This method can meet the requirements of pressure control for orchard pipeline spraying system.