代码不在循环内部工作，而是在循环之外工作。

Question

我有一段代码显示了一些奇怪的行为。当将代码排除在for循环之外时，代码的工作原理是一样的，但是一旦我将它放置在for循环中，它就会一次又一次地重复相同的值。

  const double *north = cp->getValues();
  angle1 = atan2(north[1], north[2]);
  bearing = (angle1 - 1.5708) / M_PI * 180.0;
  std::cout<<"Bearing inside : "<<bearing<<std::endl;
  if (bearing < 0.0)
    bearing = bearing + 360.0;
  t = abs(bearing - turn);

这部分代码应该在对象每次旋转时更新*north。每当我将这些代码保存在循环之外时，就会发生这种情况。但是，如果代码保存在如下所示的for循环中，那么*north的值将保持不变。

    for(int i=0;i<100;i++)
    {
      double t_modifier = (180.0 - abs(t)) / 180.0;
      double threshold = 2.0;
      double Speedleft = 1.0;
      double Speedright = 1.0;
      int identifier;
      if(int(t)<0){
        Speedleft = -1;
      }
      else if(int(t)>0){
        Speedright = -1;
      }
      leftSpeed = threshold * Speedleft;
      rightSpeed = threshold * Speedright;
      {
        wheels[0]->setVelocity(leftSpeed);
        wheels[1]->setVelocity(rightSpeed);
        wheels[2]->setVelocity(leftSpeed);
        wheels[3]->setVelocity(rightSpeed);
      }
      
      const double *north = cp->getValues();
      angle1 = atan2(north[1], north[2]);
      bearing = (angle1 - 1.5708) / M_PI * 180.0;
      std::cout<<"Bearing inside : "<<bearing<<std::endl;
      if (bearing < 0.0)
        bearing = bearing + 360.0;
      t = abs(bearing - turn);
    }

Answer 1

您应该在循环中调用step方法：

https://cyberbotics.com/doc/reference/robot#wb_robot_step

对step方法的深入解释：

https://cyberbotics.com/doc/guide/controller-programming#the-step-and-wb_robot_step-functions