An simple class to compute pid with ajustable parameters

pid.py

class PID:
  def __init__(
    self,
    Kp = 10,
    Ki = 1,
    Kd = 1,
    N = 20,
    Ts = 0.01,
  ):
    #user-adjustable parameters
    self.Kp = Kp
    self.Ki = Ki
    self.Kd = Kd
    self.N = N
    self.Ts = Ts

    # computed parameters
    self.a0 = (1+N*Ts)
    self.a1 = -(2 + N*Ts)
    self.a2 = 1
    self.b0 = Kp*(1+N*Ts) + Ki*Ts*(1+N*Ts) + Kd*N
    self.b1 = -(Kp*(2+N*Ts) + Ki*Ts + 2*Kd*N)
    self.b2 = Kp + Kd*N

    self.ku1 = self.a1/self.a0
    self.ku2 = self.a2/self.a0
    self.ke0 = self.b0/self.a0
    self.ke1 = self.b1/self.a0
    self.ke2 = self.b2/self.a0

    # global variables
    ##variables used in PID computation
    self.e2 = 0.0
    self.e1 = 0.0
    self.e0 = 0.0
    self.u2 = 0.0
    self.u1 = 0.0
    self.u0 = 0.0

    self.r = 0.0 # command
  
  def change_parameters(
    self,
    Kp = 10,
    Ki = 1,
    Kd = 1,
    N = 20,
    Ts = 0.01,
  ):
    #user-adjustable parameters
    self.Kp = Kp
    self.Ki = Ki
    self.Kd = Kd
    self.N = N
    self.Ts = Ts


  def compute(self, y = 1):
    self.e2=self.e1
    self.e1=self.e0
    self.u2=self.u1
    self.u1=self.u0

    self.e0 = self.r - y #compute new error

    self.u0 = -self.ku1*self.u1 - self.ku2*self.u2 + self.ke0*self.e0 + self.ke1*self.e1 + self.ke2*self.e2 # pid discrete form

    # if self.u0 > UMAX: self.u0 = UMAX #limit to DAC or PWM range
    # if self.u0 < UMIN: self.u0 = UMIN
    return self.u0