Added example reward functions.

reward-example-encourage-racing-line.py

@@ -0,0 +1,46 @@
+import math
+def reward_function(params):
+
+    track_width = params['track_width']
+    distance_from_center = params['distance_from_center']
+    steering = abs(params['steering_angle'])
+    direction_stearing=params['steering_angle']
+    speed = params['speed']
+    steps = params['steps']
+    progress = params['progress']
+    all_wheels_on_track = params['all_wheels_on_track']
+    ABS_STEERING_THRESHOLD = 15
+    SPEED_TRESHOLD = 5
+    TOTAL_NUM_STEPS = 85
+
+    # Read input variables
+    waypoints = params['waypoints']
+    closest_waypoints = params['closest_waypoints']
+    heading = params['heading']
+
+    reward = 1.0
+
+    if progress == 100:
+        reward += 100
+
+    # Calculate the direction of the center line based on the closest waypoints
+    next_point = waypoints[closest_waypoints[1]]
+    prev_point = waypoints[closest_waypoints[0]]
+    # Calculate the direction in radius, arctan2(dy, dx), the result is (-pi, pi) in radians
+    track_direction = math.atan2(next_point[1] - prev_point[1], next_point[0] - prev_point[0]) 
+    # Convert to degree
+    track_direction = math.degrees(track_direction)
+    # Calculate the difference between the track direction and the heading direction of the car
+    direction_diff = abs(track_direction - heading)
+    # Penalize the reward if the difference is too large
+    DIRECTION_THRESHOLD = 10.0
+
+    malus=1
+
+    if direction_diff > DIRECTION_THRESHOLD:
+        malus=1-(direction_diff/50)
+        if malus<0 or malus>1:
+            malus = 0
+        reward *= malus
+
+    return reward