Guard governor model parameters

Copilot · web-flow · commit 1d43b32f8a3b · 2026-07-01T19:23:35.000Z
diff --git a/examples/steam_engine_governor.py b/examples/steam_engine_governor.py
@@ -35,6 +35,8 @@
     'sim_time': 25.0,
 }
 SETTLING_TOLERANCE = 0.02
+MIN_SETTLING_TOLERANCE = 1e-3
+NUM_DOMINANT_POLES = 2
 
 
 def create_governor_system(params):
@@ -46,6 +48,12 @@ def create_governor_system(params):
     kt = params['kt']
     inertia = params['j']
     damping = params['b']
+    for name, value in (
+        ('ti', ti), ('tg', tg), ('ts', ts), ('kt', kt), ('j', inertia)):
+        if value <= 0:
+            raise ValueError(f'{name} must be positive')
+    if damping < 0:
+        raise ValueError('b must be nonnegative')
     ki = kp / ti
 
     a_matrix = np.array([
@@ -110,7 +118,9 @@ def summarize_response(system, time, outputs, target):
     final_speed = speed[-1]
     peak_speed = np.max(speed)
     minimum_speed = np.min(speed)
-    tolerance = max(SETTLING_TOLERANCE * max(abs(target), abs(final_speed)), 1e-3)
+    tolerance = max(
+        SETTLING_TOLERANCE * max(abs(target), abs(final_speed)),
+        MIN_SETTLING_TOLERANCE)
     if abs(target) < 1e-9:
         overshoot = 0.0
     elif target > 0:
@@ -120,7 +130,8 @@ def summarize_response(system, time, outputs, target):
     steady_state_error = target - final_speed
     poles = list(ct.poles(system))
     # Use the least stable (rightmost) poles as the dominant dynamics.
-    dominant_poles = sorted(poles, key=lambda pole: pole.real)[-min(2, len(poles)):]
+    dominant_poles = sorted(
+        poles, key=lambda pole: pole.real)[-min(NUM_DOMINANT_POLES, len(poles)):]
     damping_ratios = []
     for pole in dominant_poles:
         magnitude = abs(pole)
