python实现PID算法及测试的例子

import timeclass 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

import PIDimport timeimport matplotlibmatplotlib.use("TkAgg")import matplotlib.pyplot as pltimport numpy as npfrom 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1def 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)