import numpy as np
from numbers import Number
from openpilot.common.numpy_fast import clip, interp
[docs]
class PIDController():
def __init__(self, k_p, k_i, k_f=0., k_d=0., pos_limit=1e308, neg_limit=-1e308, rate=100):
self._k_p = k_p
self._k_i = k_i
self._k_d = k_d
self.k_f = k_f # feedforward gain
if isinstance(self._k_p, Number):
self._k_p = [[0], [self._k_p]]
if isinstance(self._k_i, Number):
self._k_i = [[0], [self._k_i]]
if isinstance(self._k_d, Number):
self._k_d = [[0], [self._k_d]]
self.pos_limit = pos_limit
self.neg_limit = neg_limit
self.i_unwind_rate = 0.3 / rate
self.i_rate = 1.0 / rate
self.speed = 0.0
self.reset()
@property
def k_p(self):
return interp(self.speed, self._k_p[0], self._k_p[1])
@property
def k_i(self):
return interp(self.speed, self._k_i[0], self._k_i[1])
@property
def k_d(self):
return interp(self.speed, self._k_d[0], self._k_d[1])
@property
def error_integral(self):
return self.i/self.k_i
[docs]
def reset(self):
self.p = 0.0
self.i = 0.0
self.d = 0.0
self.f = 0.0
self.control = 0
[docs]
def update(self, error, error_rate=0.0, speed=0.0, override=False, feedforward=0., freeze_integrator=False):
self.speed = speed
self.p = float(error) * self.k_p
self.f = feedforward * self.k_f
self.d = error_rate * self.k_d
if override:
self.i -= self.i_unwind_rate * float(np.sign(self.i))
else:
i = self.i + error * self.k_i * self.i_rate
control = self.p + i + self.d + self.f
# Update when changing i will move the control away from the limits
# or when i will move towards the sign of the error
if ((error >= 0 and (control <= self.pos_limit or i < 0.0)) or
(error <= 0 and (control >= self.neg_limit or i > 0.0))) and \
not freeze_integrator:
self.i = i
control = self.p + self.i + self.d + self.f
self.control = clip(control, self.neg_limit, self.pos_limit)
return self.control