How to translate length to position coordinates and vice versa of bezier curve?

I am working on a robotic project where the robot moves on the track. Please look at the attached picture. The cubes object placed at the end of the track(bezier curve) are the home and target positions. Now to move the robot, I am using the steering actuator with path-following.

My robot always get a distance value it has to move from the current position and I need to set the target cube position to that distance on the track. I am not sure, how can I get the target position coordinate only on the track by supplying the distance from start of the track. The idea then is to set the position of the target cube object to the obtained coordinate from the supplied length and make the robot move there.

Please help me in getting the target coordinate position on the track from the distance value. Thanks!