brake isn't working on R2025a

[MoradSayed]

Describe the Bug
So i downloaded webots through apt and opened the city.wbt world and played with it a little bit, then i edited the controls to try different features and when i wanted to try the brakes it didn't work (there was no effect in the speed of the vehicle).

So i made a test case where i moved the vehicle 70m backward for its spawn point and driven it till a specific line, then i tried it with:

1. normal stopping (caused by setting speed to 0 when I'm release the UP key)
2. braking + setting speed to 0 at the same time

and indeed there were no difference at all "brakes have no effect on the vehicle whatsoever"

Note: all tests where made with autodrive and enable_collision_avoidance being set to false.

Steps to Reproduce

1. open the city.wbt world
2. change those two functions in the original controller

void check_keyboard() {
  char u = 0, d = 0, r = 0, l = 0;
  int key;
  double s;

  // Read all currently pressed keys
  while ((key = wb_keyboard_get_key()) != -1) {
    switch (key) {
      case WB_KEYBOARD_UP:
        set_speed(speed + 0.5);
        u = 1;
        break;
      case WB_KEYBOARD_DOWN:
        if (wbu_driver_get_current_speed() > 1){
          wbu_driver_set_brake_intensity(1.0);
        } else {
          set_speed(speed - 0.1);
        }
        d = 1;
        break;
      case WB_KEYBOARD_RIGHT:
        set_autodrive(false);
        s = wbu_driver_get_current_speed();
        set_steering_angle(+0.5*(80.0-s)/80.0);   // 80.0 is used as a max comp speed (max_comp_s > max_s)
        r = 1;
        break;
      case WB_KEYBOARD_LEFT:
        set_autodrive(false);
        s = wbu_driver_get_current_speed();
        set_steering_angle(-0.5*(80.0-s)/80.0);   // 80.0 is used as a max comp speed (max_comp_s > max_s)
        l = 1;
        break;
      case 'A':
        set_autodrive(true);
        break;
    }
  }

  if (!autodrive) {
    if (!u && !d) {
      set_speed(0);
    }
    if (!l && !r) {
      int sign = -1*copysign(1, steering_angle);
      if (copysign(1, manual_steering + sign) == copysign(1, manual_steering)){  // if in the same side
        change_manual_steer_angle(sign * -1);  // Reset steering
      } else {  // if going to opposite side
        set_steering_angle(0);
      }
    }
  }
}

and

void set_speed(double kmh) {
  // max speed
  if (kmh > 60.0)  // 250
    kmh = 60.0;
  else if (kmh < -20.0)
    kmh = -20.0;
    
  speed = kmh;

  printf("setting speed to %g km/h\n", kmh);
  wbu_driver_set_cruising_speed(kmh);
}

3. try the brakes by pressing DOWN

Expected behavior
Brakes (ie. wbu_driver_set_brake_intensity(1)) will not have any effect on the vehicle.

Screenshots

1. Starting point with red line as the release or brake point (depending on the test case)
   

2. first case (normal deceleration: set_speed(0)) stopping point:
   

3. second case (brakes wbu_driver_set_brake_intensity(1) + noraml deceleration set_speed(0)) stopping point:
   

System

• Operating System: Linux Ubuntu 22.04
• Graphics Card: NVIDIA GeForce RTX 3060 6 GB

[ShuffleWire]

AFAIK, the Brake device itself work, given that the sample world brake.wbtwork fine
Could you try to simply your example down to a simpler world in the direction of making it a simple brake, until it work again ?

[ShuffleWire]

From what I'm seen, the brake works,
Please try to review your code, and if you don't find anything obvious, make a simpler code, there are a lot of code not relevant for your bug.
If you struggle with that, please ask for help

[MoradSayed]

Hi there, sorry for the late reply.

make a simpler code, there are a lot of code not relevant for your bug.

Yeah, I think I overcomplicated my description of the issue. It all boils down to wbu_driver_set_brake_intensity(1) not working in the city.wbt world. which tbh I only used it as it was mentioned and used in the provided controller by Webots (but it doesn't work).

I found a workaround to this problem. By invoking the brake device of each wheel directly and setting the .setDampingConstant as I want. Don't know if this is okay or not, but it works! Here's a simple version of the working code:

from controller import Brake

class VehicleController:
    def __init__(self): 
        self.brakes = self.init_brakes()

    def init_brakes(self):
        lf = "left_front_brake"
        rf = "right_front_brake"
        lr = "left_rear_brake"
        rr = "right_rear_brake"
        brakes = [Brake(lf), Brake(rf), Brake(lr), Brake(rr)]
        return brakes
    
    def set_brake_force(self, normalized_force):
        for b in self.brakes:
            b.setDampingConstant(normalized_force*1200)

controller = VehicleController()
controller.set_brake_force(0.85)

Sorry for mixing between C function wbu_driver_set_brake_intensity(1) and my Python solution, but I just wanted to keep referring to the C version of the function as it is the one used in the city.wbt's BMW X5 controller.