python实现PID算法及测试的例子

更新时间：2020-07-22 01:00:01 作者：startmvc

PID算法实现importtimeclassPID:def__init__(self,P=0.2,I=0.0,D=0.0):self.Kp=Pself.Ki=Iself.Kd=Dself.sample_time=0.00se

PID算法实现


import time

class PID:
 def __init__(self, P=0.2, I=0.0, D=0.0):
 self.Kp = P
 self.Ki = I
 self.Kd = D
 self.sample_time = 0.00
 self.current_time = time.time()
 self.last_time = self.current_time
 self.clear()
 def clear(self):
 self.SetPoint = 0.0
 self.PTerm = 0.0
 self.ITerm = 0.0
 self.DTerm = 0.0
 self.last_error = 0.0
 self.int_error = 0.0
 self.windup_guard = 20.0
 self.output = 0.0
 def update(self, feedback_value):
 error = self.SetPoint - feedback_value
 self.current_time = time.time()
 delta_time = self.current_time - self.last_time
 delta_error = error - self.last_error
 if (delta_time >= self.sample_time):
 self.PTerm = self.Kp * error#比例
 self.ITerm += error * delta_time#积分
 if (self.ITerm < -self.windup_guard):
 self.ITerm = -self.windup_guard
 elif (self.ITerm > self.windup_guard):
 self.ITerm = self.windup_guard
 self.DTerm = 0.0
 if delta_time > 0:
 self.DTerm = delta_error / delta_time
 self.last_time = self.current_time
 self.last_error = error
 self.output = self.PTerm + (self.Ki * self.ITerm) + (self.Kd * self.DTerm)
 def setKp(self, proportional_gain):
 self.Kp = proportional_gain
 def setKi(self, integral_gain):
 self.Ki = integral_gain
 def setKd(self, derivative_gain):
 self.Kd = derivative_gain
 def setWindup(self, windup):
 self.windup_guard = windup
 def setSampleTime(self, sample_time):
 self.sample_time = sample_time

测试PID算法


import PID
import time
import matplotlib
matplotlib.use("TkAgg")
import matplotlib.pyplot as plt
import numpy as np
from scipy.interpolate import spline
#这个程序的实质就是在前九秒保持零输出，在后面的操作中在传递函数为某某的系统中输出1

def test_pid(P = 0.2, I = 0.0, D= 0.0, L=100):
 """Self-test PID class

 .. note::
 ...
 for i in range(1, END):
 pid.update(feedback)
 output = pid.output
 if pid.SetPoint > 0:
 feedback += (output - (1/i))
 if i>9:
 pid.SetPoint = 1
 time.sleep(0.02)
 ---
 """
 pid = PID.PID(P, I, D)

 pid.SetPoint=0.0
 pid.setSampleTime(0.01)

 END = L
 feedback = 0

 feedback_list = []
 time_list = []
 setpoint_list = []

 for i in range(1, END):
 pid.update(feedback)
 output = pid.output
 if pid.SetPoint > 0:
 feedback +=output# (output - (1/i))控制系统的函数
 if i>9:
 pid.SetPoint = 1
 time.sleep(0.01)

 feedback_list.append(feedback)
 setpoint_list.append(pid.SetPoint)
 time_list.append(i)

 time_sm = np.array(time_list)
 time_smooth = np.linspace(time_sm.min(), time_sm.max(), 300)
 feedback_smooth = spline(time_list, feedback_list, time_smooth)
 plt.figure(0)
 plt.plot(time_smooth, feedback_smooth)
 plt.plot(time_list, setpoint_list)
 plt.xlim((0, L))
 plt.ylim((min(feedback_list)-0.5, max(feedback_list)+0.5))
 plt.xlabel('time (s)')
 plt.ylabel('PID (PV)')
 plt.title('TEST PID')

 plt.ylim((1-0.5, 1+0.5))

 plt.grid(True)
 plt.show()

if __name__ == "__main__":
 test_pid(1.2, 1, 0.001, L=80)
# test_pid(0.8, L=50)

结果