Homework 5.4 unit tests

homework5.4/task.py

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+# --------------
+# User Instructions
+# 
+# Define a function cte in the robot class that will
+# compute the crosstrack error for a robot on a
+# racetrack with a shape as described in the video.
+#
+# You will need to base your error calculation on
+# the robot's location on the track. Remember that 
+# the robot will be traveling to the right on the
+# upper straight segment and to the left on the lower
+# straight segment.
+#
+# --------------
+# Grading Notes
+#
+# We will be testing your cte function directly by
+# calling it with different robot locations and making
+# sure that it returns the correct crosstrack error.  
+
+from math import *
+import random
+import sys
+
+
+# ------------------------------------------------
+# 
+# this is the robot class
+#
+
+class robot:
+
+    # --------
+    # init: 
+    #    creates robot and initializes location/orientation to 0, 0, 0
+    #
+
+    def __init__(self, length = 20.0):
+        self.x = 0.0
+        self.y = 0.0
+        self.orientation = 0.0
+        self.length = length
+        self.steering_noise = 0.0
+        self.distance_noise = 0.0
+        self.steering_drift = 0.0
+
+    # --------
+    # set: 
+    # sets a robot coordinate
+    #
+
+    def set(self, new_x, new_y, new_orientation):
+
+        self.x = float(new_x)
+        self.y = float(new_y)
+        self.orientation = float(new_orientation) % (2.0 * pi)
+
+
+    # --------
+    # set_noise: 
+    # sets the noise parameters
+    #
+
+    def set_noise(self, new_s_noise, new_d_noise):
+        # makes it possible to change the noise parameters
+        # this is often useful in particle filters
+        self.steering_noise = float(new_s_noise)
+        self.distance_noise = float(new_d_noise)
+
+    # --------
+    # set_steering_drift: 
+    # sets the systematical steering drift parameter
+    #
+
+    def set_steering_drift(self, drift):
+        self.steering_drift = drift
+
+    # --------
+    # move: 
+    #    steering = front wheel steering angle, limited by max_steering_angle
+    #    distance = total distance driven, most be non-negative
+
+    def move(self, steering, distance, 
+             tolerance = 0.001, max_steering_angle = pi / 4.0):
+
+        if steering > max_steering_angle:
+            steering = max_steering_angle
+        if steering < -max_steering_angle:
+            steering = -max_steering_angle
+        if distance < 0.0:
+            distance = 0.0
+
+
+        # make a new copy
+        res = robot()
+        res.length         = self.length
+        res.steering_noise = self.steering_noise
+        res.distance_noise = self.distance_noise
+        res.steering_drift = self.steering_drift
+
+        # apply noise
+        steering2 = random.gauss(steering, self.steering_noise)
+        distance2 = random.gauss(distance, self.distance_noise)
+
+        # apply steering drift
+        steering2 += self.steering_drift
+
+        # Execute motion
+        turn = tan(steering2) * distance2 / res.length
+
+        if abs(turn) < tolerance:
+
+            # approximate by straight line motion
+
+            res.x = self.x + (distance2 * cos(self.orientation))
+            res.y = self.y + (distance2 * sin(self.orientation))
+            res.orientation = (self.orientation + turn) % (2.0 * pi)
+
+        else:
+
+            # approximate bicycle model for motion
+
+            radius = distance2 / turn
+            cx = self.x - (sin(self.orientation) * radius)
+            cy = self.y + (cos(self.orientation) * radius)
+            res.orientation = (self.orientation + turn) % (2.0 * pi)
+            res.x = cx + (sin(res.orientation) * radius)
+            res.y = cy - (cos(res.orientation) * radius)
+
+        return res
+
+
+
+
+    def __repr__(self):
+        return '[x=%.5f y=%.5f orient=%.5f]'  % (self.x, self.y, self.orientation)
+
+
+############## ONLY ADD / MODIFY CODE BELOW THIS LINE ####################
+
+    def cte(self, radius):
+        # 
+        #
+        # Add code here
+        #
+        #            
+
+        return cte
+
+############## ONLY ADD / MODIFY CODE ABOVE THIS LINE ####################
+
+
+
+