Intial commit

loop.py

@@ -0,0 +1,97 @@
+import math
+import numpy as np
+
+try:
+    from lib import RTLFWriter
+except ImportError:
+    class RTLFWriter:
+        def __init__(self, *args, **kwargs): pass
+        def __enter__(self): return self
+        def __exit__(self, *args): pass
+        def write_record(self, *args): pass
+
+
+def simulate_closed_circuit(filename, car_id=7):
+    track_name = "Closed Circuit GP"
+
+    # Real-world reference point (Silverstone-ish)
+    base_lat = 52.0733
+    base_lon = -1.0147
+
+    dt = 0.05
+    lap_time = 95.0
+    samples = int(lap_time / dt)
+
+    # Track size in METERS (realistic)
+    a = 1200.0   # main straight length scale
+    b = 800.0
+
+    theta = np.linspace(0, 2 * math.pi, samples)
+
+    # Track shape (meters)
+    x_m = (
+        a * np.cos(theta)
+        + 220 * np.cos(3 * theta)
+        + 90 * np.sin(5 * theta)
+    )
+    y_m = (
+        b * np.sin(theta)
+        + 170 * np.sin(2 * theta)
+        - 70 * np.cos(4 * theta)
+    )
+
+    # Convert meters → degrees
+    meters_per_deg_lat = 111_320.0
+    meters_per_deg_lon = meters_per_deg_lat * math.cos(math.radians(base_lat))
+
+    lat = base_lat + (y_m / meters_per_deg_lat)
+    lon = base_lon + (x_m / meters_per_deg_lon)
+
+    # Derivatives (still done in meters for physics)
+    dx = np.gradient(x_m, dt)
+    dy = np.gradient(y_m, dt)
+    ddx = np.gradient(dx, dt)
+    ddy = np.gradient(dy, dt)
+
+    curvature = np.abs(dx * ddy - dy * ddx) / np.power(dx*dx + dy*dy, 1.5)
+    curvature = np.nan_to_num(curvature)
+
+    # Speed profile
+    max_speed = 82.0   # ~295 km/h
+    min_speed = 30.0
+    speed = max_speed - 850 * curvature
+    speed = np.clip(speed, min_speed, max_speed)
+
+    # Acceleration
+    heading_norm = np.hypot(dx, dy)
+    ax = np.gradient(speed * dx / heading_norm, dt)
+    ay = np.gradient(speed * dy / heading_norm, dt)
+    az = np.zeros_like(ax)
+
+    # Forces
+    mass = 1250.0
+    fx = mass * ax
+    fy = mass * ay
+    fz = np.ones_like(fx) * mass * 9.81
+
+    with RTLFWriter(filename, car_id, track_name) as writer:
+        t = 0.0
+        for i in range(samples):
+            writer.write_record(
+                t,
+                float(lon[i]),
+                float(lat[i]),
+                float(fx[i]),
+                float(fy[i]),
+                float(fz[i]),
+                float(ax[i]),
+                float(ay[i]),
+                float(az[i]),
+                float(speed[i])
+            )
+            t += dt
+
+
+if __name__ == "__main__":
+    simulate_closed_circuit("closed_loop.rtl")
+    print("Closed circuit simulation complete.")