Help or Ideas on Robot to carry a bridge and cross 8in gap

[rcdooley]

This is a school project that i am working on and trying to get knowledge from experienced builders.

Requirements:  no more than 4 AA batteries
                      traverse obstacles 1.5 high
                      dim. of 12Lx6Wx5H
                      travel an obstacle cousre of about 16ft and perform a 180 on a 10x24in platform

I am planning on using a 4wd system that can steer like a tank and have a 6 in wheel base and track width 6 in
The bridge will be 4in wide and since the car has a 6in wheel base with 5in wheels then the 4wd will push itself over the bridge and then the front wheels will pull it on the next platform.
Planning on using two mabuchi fa-260 ra 2670    6300rpm  52gcm motors but not sure how to make it tank steering, probably one on each side to drive each side individually with potentiometers for the controller.

I have seen robots using servos to propell and controll the steering on the robot, good idea?

I do rc airplanes but do not know how to make the servos continue turning?

[Admin]

I know Ive posted this bot in a few other places, but it looks really close to what you seem to want . . .
http://www.societyofrobots.com/robot_asme.shtml
We put a timing belt on both sides so that the wheels are linked together.

For tank steering, what you want is called differential drive.

Tutorial to modify servos for continuous motion.

There are also various motor drivers out there that you can use that take RC commands, if you dont want to use servos.