Files
dragonpilot/selfdrive/controls/lib/pid.py
2020-10-30 15:23:01 +10:00

186 lines
5.6 KiB
Python

import numpy as np
from common.numpy_fast import clip, interp
def apply_deadzone(error, deadzone):
if error > deadzone:
error -= deadzone
elif error < - deadzone:
error += deadzone
else:
error = 0.
return error
class PIController:
def __init__(self, k_p, k_i, k_f=1., pos_limit=None, neg_limit=None, rate=100, sat_limit=0.8, convert=None):
self._k_p = k_p # proportional gain
self._k_i = k_i # integral gain
self.k_f = k_f # feedforward gain
self.pos_limit = pos_limit
self.neg_limit = neg_limit
self.sat_count_rate = 1.0 / rate
self.i_unwind_rate = 0.3 / rate
self.i_rate = 1.0 / rate
self.sat_limit = sat_limit
self.convert = convert
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])
def _check_saturation(self, control, check_saturation, error):
saturated = (control < self.neg_limit) or (control > self.pos_limit)
if saturated and check_saturation and abs(error) > 0.1:
self.sat_count += self.sat_count_rate
else:
self.sat_count -= self.sat_count_rate
self.sat_count = clip(self.sat_count, 0.0, 1.0)
return self.sat_count > self.sat_limit
def reset(self):
self.p = 0.0
self.i = 0.0
self.f = 0.0
self.sat_count = 0.0
self.saturated = False
self.control = 0
def update(self, setpoint, measurement, speed=0.0, check_saturation=True, override=False, feedforward=0., deadzone=0., freeze_integrator=False):
self.speed = speed
error = float(apply_deadzone(setpoint - measurement, deadzone))
self.p = error * self.k_p
self.f = feedforward * self.k_f
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 + self.f + i
if self.convert is not None:
control = self.convert(control, speed=self.speed)
# 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.f + self.i
if self.convert is not None:
control = self.convert(control, speed=self.speed)
self.saturated = self._check_saturation(control, check_saturation, error)
self.control = clip(control, self.neg_limit, self.pos_limit)
return self.control
class PIDController:
def __init__(self, k_p, k_i, k_d, k_f=1., pos_limit=None, neg_limit=None, rate=100, sat_limit=0.8, convert=None):
self.enable_long_derivative = False
self._k_p = k_p # proportional gain
self._k_i = k_i # integral gain
self._k_d = k_d # derivative gain
self.k_f = k_f # feedforward gain
self.max_accel_d = 0.22352 # 0.5 mph/s
self.pos_limit = pos_limit
self.neg_limit = neg_limit
self.sat_count_rate = 1.0 / rate
self.i_unwind_rate = 0.3 / rate
self.rate = 1.0 / rate
self.sat_limit = sat_limit
self.convert = convert
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])
def _check_saturation(self, control, check_saturation, error):
saturated = (control < self.neg_limit) or (control > self.pos_limit)
if saturated and check_saturation and abs(error) > 0.1:
self.sat_count += self.sat_count_rate
else:
self.sat_count -= self.sat_count_rate
self.sat_count = clip(self.sat_count, 0.0, 1.0)
return self.sat_count > self.sat_limit
def reset(self):
self.p = 0.0
self.id = 0.0
self.f = 0.0
self.sat_count = 0.0
self.saturated = False
self.control = 0
self.last_setpoint = 0.0
self.last_error = 0.0
def update(self, setpoint, measurement, speed=0.0, check_saturation=True, override=False, feedforward=0., deadzone=0., freeze_integrator=False):
self.speed = speed
error = float(apply_deadzone(setpoint - measurement, deadzone))
self.p = error * self.k_p
self.f = feedforward * self.k_f
if override:
self.id -= self.i_unwind_rate * float(np.sign(self.id))
else:
i = self.id + error * self.k_i * self.rate
control = self.p + self.f + i
if self.convert is not None:
control = self.convert(control, speed=self.speed)
# 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.id = i
if self.enable_long_derivative:
if abs(setpoint - self.last_setpoint) / self.rate < self.max_accel_d: # if setpoint isn't changing much
d = self.k_d * (error - self.last_error)
if (self.id > 0 and self.id + d >= 0) or (self.id < 0 and self.id + d <= 0): # if changing integral doesn't make it cross zero
self.id += d
control = self.p + self.f + self.id
if self.convert is not None:
control = self.convert(control, speed=self.speed)
self.saturated = self._check_saturation(control, check_saturation, error)
self.last_setpoint = float(setpoint)
self.last_error = float(error)
self.control = clip(control, self.neg_limit, self.pos_limit)
return self.control