We had a brief meeting with Dr. Furman today, discussing tracking the location of the podcar to ensure that they correctly check in at stations and to avoid collisions.
One idea was to simply use a motor with an encoder. As an encoder measures angular displacement of a motor, this can solve checking in at stations. However, this is not an easy solution for avoiding collisions between one podcar and the one in front of it, as it would involve obtaining the location of the podcar using the encoder attached to its motor and doing the same for the next podcar. Therefore, we would still have to implement a vision sensor, such as an array of IR sensors, using a “time-of-flight” sensor attached to a servomotor, or adding to the already installed ultrasonic sensors. Many motors come equipped with an encoder already because of their ability to measure angular displacement, so if we were to pursue this route and we cannot find an affordable motor-encoder combination, we can attach an external encoder that will make contact with the track.
A second idea was to use a GPS module, which would take care of the station check-ins and the collision avoidance as well as possibly offering live-tracking of the podcar. Dr. Furman mentioned that this was attempted in the past; however, the team ran into problems, as the area that the small-scale model was set up in did not have good satellite coverage. A possible solution to this would be to add a GPS amplifier.
The latter idea seems to be the more efficient one, as it could offer live-tracking, so it may be worth pursuing. Research is currently being done into the different GPS modules offered on various websites.