python differential drive robot simulation [ part 2 ]: implementation

in this step-by-step tutorial, we will simulate and visualize a differential drive robot in python from scratch.
first, we explained some of the implementation details in the introductory video, and in this video we are writing the actual code and test the project.

the content :
0:00 intro
0:30 code structure
1:02 initializing the environment class and the animation loop
2:48 initializing the robot class
4:31 robot draw method (Robot class )
4:36 robot move method (Robot class )
9:25 write info method ( environment class)
11:00 trail method ( environment class)
12:22 robot reference frame ( environment class)
14:06 debugging
15:18 future work
15:35 :outro

hashtags:
#python #pythonprojects #robotics #selfdrive

[hobby_coding]

welcome to the comments section, feel free to ask questions and suggest ideas .

[goplayman]

Just a quick addition:

Theta is calculated as: (vr-vl)/L, where L is the distance between the wheels of the robot, not the width of the robot as mentioned in the video

[cauancarvalhomarotta]

That was an amazing explanation. Im new to python and to english language, and still you made me understand. Thank you!!

[batuhanatasoy]

A very good tutorial to understand the mobile robots, thank you very much for your effort

[meralkilicarslan]

Can you make 3 differential robots, one is leader, second one and third one follow the leader by distance-distance control and distance-angle control? It is how desai suggested.

[SaurabhKumar-cbms]

which software you are using to write the code
if possible can you post the link of the softwarre

[meralkilicarslan]

In my simulation, trail is not moving, it stays as a line, it doesn't go when the robot goes. Why?

def trail(self, pos):
for i in range(0, len(self.trail_set)-1):
pygame.draw.line(self.map, self.yel, (self.trail_set[i][0], self.trail_set[i][1]), (
self.trail_set[i+1][0], self.trail_set[i+1][1]))
if self.trail_set.__sizeof__() > 30000:
self.trail_set.pop(0)
self.trail_set.append(pos)

def robot_frame(self, pos, rotation):
n = 80

centerx, centery = pos
x_axis = (centerx + n * math.cos(-rotation),
centery + n * math.sin(-rotation))
y_axis = (centerx + n * math.cos(-rotation + math.pi/2),
centery + n * math.sin(-rotation + math.pi/2))
pygame.draw.line(self.map, self.red, (centerx, centery), x_axis, 3)
pygame.draw.line(self.map, self.green, (centerx, centery), y_axis, 3)

[meralkilicarslan]

In my simulation, robaot trail is not moving with the robot. Why?

def trail(self, pos):
for i in range(0, len(self.trail_set)-1):
pygame.draw.line(self.map, self.yel, (self.trail_set[i][0], self.trail_set[i][1]), (
self.trail_set[i+1][0], self.trail_set[i+1][1]))
if self.trail_set.__sizeof__() > 30000:
self.trail_set.pop(0)
self.trail_set.append(pos)

def robot_frame(self, pos, rotation):
n = 80

centerx, centery = pos
x_axis = (centerx + n * math.cos(-rotation),
centery + n * math.sin(-rotation))
y_axis = (centerx + n * math.cos(-rotation + math.pi/2),
centery + n * math.sin(-rotation + math.pi/2))
pygame.draw.line(self.map, self.red, (centerx, centery), x_axis, 3)
pygame.draw.line(self.map, self.green, (centerx, centery), y_axis, 3)

[chiragbangera]

can u do the same project using a robot like real one

[saoussanmoustaoui]

Please wich lignes of the code that make the robot rotate

[moatazkhaled]

Thank you for this video it is very helpful also, could you please share the source code :)
thanks in advance