Building a Robot - Need Advices

[Creebe]

Hello!

Well I am in second year Engineering Physics and we're building a robot this summer. We have four students in my team including myself. We're to build a robot that follows a loop of black tape on a track, and race with other robots.

I have a few questions:

1. We decided to use two motors to drive the two rear wheels, and use a servo motor with PID control to steer the front two wheels. We're wondering if it's better to use two differentials for the two rear wheels.

2. What kind of shock absorbing system should we use? The robot will probably weight at most 15 pounds. And it will have to jump off of a ramp which is probably 4-6 inches high. I'm thinking of using springs, but I haven't come up with a design yet. It would be great if you could provide a picture.

Thanks!

 

[DaveC426913]

1. We decided to use two motors to drive the two rear wheels, and use a servo motor with PID control to steer the front two wheels. We're wondering if it's better to use two differentials for the two rear wheels.

If you use two motors for the two rear wheels, why do you need a third motor to steer? Just differentially activate the rear wheels. Replace the front wheels with castors.

Alternately, use one motor to steer and the other to drive one (or both) rear wheels.

Either way, I don't see why you need more than two motors.

 

[agurvinder]

your problem points the robot is manually operated.
the explanation for diiferential by DaveC426913 is copletely justified.

for shock absorbing, i would say that for a 15 pounds load and a less that 200 m track, the rubber of the wheels itself is enough to sustain the load.
still if you feel its not safe, try searching on net for flexible brackets.
a conventional suspension would be too bulky for your config.