基于粒子群优化算法的自调节非线性PID气缸位置控制研究

Research on the application of self-regulation nonlinear PID with PSO on pneumatic actuator

气动执行机构具有加速度快、成本低、功率重量比高和在恒定负载下不会过热等优点,但同时其非线性特征突出,造成难以实现高精度位置控制。对此,在非线性PID(Nonlinear Proportion-Integral-Derivative,N-PID)控制的基础上,提出了一种自调节非线性PID(Self-regulation Nonlinear Proportion-Integral-Derivative,SN-PID)的控制策略,通过粒子群优化(Particle Swarm Optimization,PSO)算法确定速度变化参数δ和β,不断地更新速动率α,利用Popov稳定判据确定非线性增益k(e)的最大值,从而调整非线性方程的输出,提高气动系统的阶跃响应。实验结果表明:SN-PID能够对负载的变化做出及时的响应,瞬态响应速度较N-PID提高2. 2倍,系统稳态误差可达0. 01 mm,SN-PID控制器下的气缸,可以快速准确地到达指定位置,而且没有明显冲击。

The pneumatic actuator is of high moving acceleration,low cost,with high power to weight ratio and free from overheating in the case of constant load,but its nonlinearity is high evidently,so it’s hard to be used for an actuate position control. With the research on the N-PID controller,a better controller called SN-PID was proposed. The controller used PSO method to determine the velocity variables δ and β to refresh α continuously and determined the maximum k( e) value by Popov criterion,so SNPID can regulate the output of the nonlinear function and improve the step response of pneumatic positioning system. It’s proved by experiment that SN-PID can respond to load change in time,the transient response is 2. 2 times better than N-PID and its steady state error is about 0. 01 mm. Besides,the pneumatic actuator with SN-PID controller can move to the preset place quickly and without significant overshoot.