Fixed some of the PID code

This commit is contained in:
Ram Reddy 2021-02-12 15:03:51 -08:00
parent bf120ab2b3
commit fbb9fa7455
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2 changed files with 40 additions and 14 deletions

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@ -5,12 +5,10 @@
from controller import Robot, Accelerometer, Gyro
def integral(error, priorIntegral):
global timestep
return priorIntegral + error * timestep
return priorIntegral + error * (TIMESTEP+1 - TIMESTEP)
def derivative(error, priorError):
global timestep
return (error-priorError)/timestep
return (error-priorError)/(TIMESTEP+1 - TIMESTEP)
def actuatorMovement(robot, pidOutput):
#Inverse Kinematic Equation
@ -24,18 +22,45 @@ def controllerPID(robot, error, priorError, priorIntegral):
Kp = 1
Ki = 0
Kd = 0
#Usually not needed, but just in case we ever need nonstop motion
xBias = 0
yBias = 0
derivativeX = derivative(error[0], priorError[0])
derivativeY = derivative(error[1], priorError[1])
nominalValue = 0.0
Kc = 1.0 # Kc is the controller gain
tauI = 0.0 # tauI is the reset time, which is a tuning param for integral
tauD = 0.0 # tauD is derivative time. Tuning param for derivative
maxMotor = 1.0 # How big the signal that goes to the actuator is
minMotor = 0.0 # How small the signal that goes to the actuator is
integralX = integral(error[0], priorIntegral[0])
integralY = integral(error[1], priorIntegral[1])
ux = Kp*error[0] + Ki * integralX + Kd * derivativeX + xBias
uy = Kp*error[1] + Ki * integralY + Kd * derivativeY + yBias
if(TIMESTEP >= 1):
derivativeX = derivative(error[0], priorError[0])
derivativeY = derivative(error[1], priorError[1])
else:
derivativeX = 0.0
derivativeY = 0.0
ux = nominalValue + Kc*error[0] + Kc/tauI * integralX + Kc * tauD * derivativeX
if(ux > maxMotor):
ux = maxMotor
integralX = integralX - error[0]*(TIMESTEP+1 - TIMESTEP)
elif(ux < minMotor):
ux = minMotor
integralX = integralX - error[0]*(TIMESTEP+1 - TIMESTEP)
uy = nominalValue + Kc*error[1] + Kc/tauI * integralY + Kc * tauD * derivativeY
if(uy > maxMotor):
uy = maxMotor
integralY = integralY - error[1]*(TIMESTEP+1 - TIMESTEP)
elif(ux < minMotor):
uy = minMotor
integralY = integralY - error[1]*(TIMESTEP+1 - TIMESTEP)
priorError = error
priorIntegral = [integralX, integralY]
@ -65,8 +90,8 @@ def main():
robot = Robot()
# get the time step of the current world.
global timestep
timestep = int(robot.getBasicTimeStep())
global TIMESTEP
TIMESTEP = int(robot.getBasicTimeStep())
# gyroscope, accelorometer
gyro = robot.getDevice("gyro.wbt name")
@ -84,7 +109,7 @@ def main():
priorError = [0,0]
priorIntegral = [0, 0]
while robot.step(timestep) != -1:
while robot.step(TIMESTEP) != -1:
xObs, yObs = calculateZMP(gyro, accel)
error = [desiredXZMP-xObs, desiredYZMP-yObs]
controllerPID(robot, error, priorError, priorIntegral)

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@ -1,8 +1,9 @@
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