I am using C++ to write plugin. I want to write a automatic stop. If I know where to stop (dist), how to calcalate the stopping curve and make it stop correctly?

I had made one that is not accurate, and I want to improve.


Thanks for helping!

If you want to work with a brake curve, you can make use of the following physical identity for uniform acceleration:

velocity = sqrt(2 * acceleration * distance)

where:

• velocity is the speed of the train (expressed in m/s),
• acceleration is the (in this case) deceleration of the train (expressed in m/s²),
• distance is the distance from the stop point to the train (expressed in m),
• and sqrt is the square root function.

All values used in the above formula should be positive. If you want to work with velocity expressed in km/h and acceleration in km/h/s, you can use:

velocity = sqrt(7.2 * acceleration * distance)

Given the allowed velocity, you can easily check whether the train exceeds it, and then apply the brakes. This, however, is just a starting point. You might want to incorporate that the train can brake at different deceleration levels (brake notches) for a smoother braking performance.

For more information on uniform acceleration, you can also check out the formulas on the respective Wikipedia page. I leave it to you (or to others) to develop this further.

Square root is needed...

Thanks for your reply. I will further try to inprove.

How about the AI in openBVE? I think I would also try to refer to it...