# udacity373_code / unit3 / u3-hw4_circularmotion.py

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201``` ``` # -------------- # USER INSTRUCTIONS # # Write a function in the class robot called move() # # that takes self and a motion vector (this # motion vector contains a steering* angle and a # distance) as input and returns an instance of the class # robot with the appropriate x, y, and orientation # for the given motion. # # *steering is defined in the video # which accompanies this problem. # # For now, please do NOT add noise to your move function. # # Please do not modify anything except where indicated # below. # # There are test cases which you are free to use at the # bottom. If you uncomment them for testing, make sure you # re-comment them before you submit. from math import * import random # -------- # # the "world" has 4 landmarks. # the robot's initial coordinates are somewhere in the square # represented by the landmarks. # # NOTE: Landmark coordinates are given in (y, x) form and NOT # in the traditional (x, y) format! landmarks = [[0.0, 100.0], [0.0, 0.0], [100.0, 0.0], [100.0, 100.0]] # position of 4 landmarks world_size = 100.0 # world is NOT cyclic. Robot is allowed to travel "out of bounds" max_steering_angle = pi/4 # You don't need to use this value, but it is good to keep in mind the limitations of a real car. # ------------------------------------------------ # # this is the robot class # class robot: # -------- # init: # creates robot and initializes location/orientation # def __init__(self, length = 10.0): self.x = random.random() * world_size # initial x position self.y = random.random() * world_size # initial y position self.orientation = random.random() * 2.0 * pi # initial orientation self.length = length # length of robot self.bearing_noise = 0.0 # initialize bearing noise to zero self.steering_noise = 0.0 # initialize steering noise to zero self.distance_noise = 0.0 # initialize distance noise to zero def __repr__(self): return '[x=%.6s y=%.6s orient=%.6s]' % (str(self.x), str(self.y), str(self.orientation)) # -------- # set: # sets a robot coordinate # def set(self, new_x, new_y, new_orientation): if new_orientation < 0 or new_orientation >= 2 * pi: raise ValueError, 'Orientation must be in [0..2pi]' self.x = float(new_x) self.y = float(new_y) self.orientation = float(new_orientation) # -------- # set_noise: # sets the noise parameters # def set_noise(self, new_b_noise, new_s_noise, new_d_noise): # makes it possible to change the noise parameters # this is often useful in particle filters self.bearing_noise = float(new_b_noise) self.steering_noise = float(new_s_noise) self.distance_noise = float(new_d_noise) ############# ONLY ADD/MODIFY CODE BELOW HERE ################### # -------- # move: # move along a section of a circular path according to motion # def move(self, motion): # Do not change the name of this function # ADD CODE HERE epsilon = 0.001 L = self.length alpha, d = motion #angle and length of motion theta = self.orientation beta = d/L * tan(alpha) if abs(beta) < epsilon: new_x = self.x + cos(theta) * d new_y = self.y + sin(theta) * d else: R = d/beta #turning radius cx = self.x - sin(theta) * R cy = self.y + cos(theta) * R new_x = cx + sin(theta + beta) * R new_y = cy - cos(theta + beta) * R new_theta = (theta + beta) % (2*pi) result = robot(self.length) result.set(new_x, new_y, new_theta) return result ############## ONLY ADD/MODIFY CODE ABOVE HERE #################### ## IMPORTANT: You may uncomment the test cases below to test your code. ## But when you submit this code, your test cases MUST be commented ## out. Our testing program provides its own code for testing your ## move function with randomized motion data. ## -------- ## TEST CASE: ## ## 1) The following code should print: ## Robot: [x=0.0 y=0.0 orient=0.0] ## Robot: [x=10.0 y=0.0 orient=0.0] ## Robot: [x=19.861 y=1.4333 orient=0.2886] ## Robot: [x=39.034 y=7.1270 orient=0.2886] ## ## ##length = 20. ##bearing_noise = 0.0 ##steering_noise = 0.0 ##distance_noise = 0.0 ## ##myrobot = robot(length) ##myrobot.set(0.0, 0.0, 0.0) ##myrobot.set_noise(bearing_noise, steering_noise, distance_noise) ## ##motions = [[0.0, 10.0], [pi / 6.0, 10], [0.0, 20.0]] ## ##T = len(motions) ##print 'Robot: ', myrobot ##for t in range(T): ## myrobot = myrobot.move(motions[t]) ## print 'Robot: ', myrobot ## IMPORTANT: You may uncomment the test cases below to test your code. ## But when you submit this code, your test cases MUST be commented ## out. Our testing program provides its own code for testing your ## move function with randomized motion data. ## 2) The following code should print: ## Robot: [x=0.0 y=0.0 orient=0.0] ## Robot: [x=9.9828 y=0.5063 orient=0.1013] ## Robot: [x=19.863 y=2.0201 orient=0.2027] ## Robot: [x=29.539 y=4.5259 orient=0.3040] ## Robot: [x=38.913 y=7.9979 orient=0.4054] ## Robot: [x=47.887 y=12.400 orient=0.5067] ## Robot: [x=56.369 y=17.688 orient=0.6081] ## Robot: [x=64.273 y=23.807 orient=0.7094] ## Robot: [x=71.517 y=30.695 orient=0.8108] ## Robot: [x=78.027 y=38.280 orient=0.9121] ## Robot: [x=83.736 y=46.485 orient=1.0135] ## ## ##length = 20. ##bearing_noise = 0.0 ##steering_noise = 0.0 ##distance_noise = 0.0 ## ##myrobot = robot(length) ##myrobot.set(0.0, 0.0, 0.0) ##myrobot.set_noise(bearing_noise, steering_noise, distance_noise) ## ##motions = [[0.2, 10.] for row in range(10)] ## ##T = len(motions) ## ##print 'Robot: ', myrobot ##for t in range(T): ## myrobot = myrobot.move(motions[t]) ## print 'Robot: ', myrobot ## IMPORTANT: You may uncomment the test cases below to test your code. ## But when you submit this code, your test cases MUST be commented ## out. Our testing program provides its own code for testing your ## move function with randomized motion data. ```