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70 lines
1.9 KiB
70 lines
1.9 KiB
import numpy as np
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from numbers import Number
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class PIDController:
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def __init__(self, k_p, k_i, k_f=0., k_d=0., pos_limit=1e308, neg_limit=-1e308, rate=100):
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self._k_p = k_p
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self._k_i = k_i
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self._k_d = k_d
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self.k_f = k_f # feedforward gain
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if isinstance(self._k_p, Number):
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self._k_p = [[0], [self._k_p]]
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if isinstance(self._k_i, Number):
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self._k_i = [[0], [self._k_i]]
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if isinstance(self._k_d, Number):
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self._k_d = [[0], [self._k_d]]
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self.pos_limit = pos_limit
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self.neg_limit = neg_limit
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self.i_unwind_rate = 0.3 / rate
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self.i_rate = 1.0 / rate
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self.speed = 0.0
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self.reset()
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@property
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def k_p(self):
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return np.interp(self.speed, self._k_p[0], self._k_p[1])
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@property
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def k_i(self):
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return np.interp(self.speed, self._k_i[0], self._k_i[1])
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@property
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def k_d(self):
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return np.interp(self.speed, self._k_d[0], self._k_d[1])
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@property
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def error_integral(self):
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return self.i/self.k_i
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def reset(self):
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self.p = 0.0
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self.i = 0.0
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self.d = 0.0
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self.f = 0.0
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self.control = 0
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def update(self, error, error_rate=0.0, speed=0.0, override=False, feedforward=0., freeze_integrator=False):
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self.speed = speed
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self.p = float(error) * self.k_p
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self.f = feedforward * self.k_f
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self.d = error_rate * self.k_d
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if override:
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self.i -= self.i_unwind_rate * float(np.sign(self.i))
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else:
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if not freeze_integrator:
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self.i = self.i + error * self.k_i * self.i_rate
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# Clip i to prevent exceeding control limits
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control_no_i = self.p + self.d + self.f
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control_no_i = np.clip(control_no_i, self.neg_limit, self.pos_limit)
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self.i = np.clip(self.i, self.neg_limit - control_no_i, self.pos_limit - control_no_i)
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control = self.p + self.i + self.d + self.f
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self.control = np.clip(control, self.neg_limit, self.pos_limit)
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return self.control
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