IQ.Pilot Release Commit @ b6534c0

iqpilot/common/pid.py

@@ -0,0 +1,57 @@
+import numpy as np
+from numbers import Number
+
+class PIDController:
+  def __init__(self, k_p, k_i, k_d=0., pos_limit=1e308, neg_limit=-1e308, rate=100):
+    self._k_p: list[list[float]] = [[0], [k_p]] if isinstance(k_p, Number) else k_p
+    self._k_i: list[list[float]] = [[0], [k_i]] if isinstance(k_i, Number) else k_i
+    self._k_d: list[list[float]] = [[0], [k_d]] if isinstance(k_d, Number) else k_d
+
+    self.set_limits(pos_limit, neg_limit)
+
+    self.i_dt = 1.0 / rate
+    self.speed = 0.0
+
+    self.reset()
+
+  @property
+  def k_p(self):
+    return np.interp(self.speed, self._k_p[0], self._k_p[1])
+
+  @property
+  def k_i(self):
+    return np.interp(self.speed, self._k_i[0], self._k_i[1])
+
+  @property
+  def k_d(self):
+    return np.interp(self.speed, self._k_d[0], self._k_d[1])
+
+  def reset(self):
+    self.p = 0.0
+    self.i = 0.0
+    self.d = 0.0
+    self.f = 0.0
+    self.control = 0
+
+  def set_limits(self, pos_limit, neg_limit):
+    self.pos_limit = pos_limit
+    self.neg_limit = neg_limit
+
+  def update(self, error, error_rate=0.0, speed=0.0, feedforward=0., freeze_integrator=False):
+    self.speed = speed
+    self.p = self.k_p * float(error)
+    self.d = self.k_d * error_rate
+    self.f = feedforward
+
+    if not freeze_integrator:
+      i = self.i + self.k_i * self.i_dt * error
+
+      # Don't allow windup if already clipping
+      test_control = self.p + i + self.d + self.f
+      i_upperbound = self.i if test_control > self.pos_limit else self.pos_limit
+      i_lowerbound = self.i if test_control < self.neg_limit else self.neg_limit
+      self.i = np.clip(i, i_lowerbound, i_upperbound)
+
+    control = self.p + self.i + self.d + self.f
+    self.control = np.clip(control, self.neg_limit, self.pos_limit)
+    return self.control