Touchsensors in the Bumpers legal?

[Kevka]

Hi,
do you think it would be legal to install touch sensors in the bumpers?
And if so, which type would you use?
It would be hard to cover the whole wisth of a robot with microswitches.
Best Regards Kevin

[Mark McLeod]

The touch sensors cannot be incorporated into the bumper.
They have to be behind the bumper within the confines of the robot frame that supports the bumpers.

<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.

There is a rule that allows us to push them out as far as the bumper front edge, but only for a maximum of 2 seconds.

[Al Skierkiewicz]

Kevka,
Within the bumpers is restricted as Mark has pointed out but it is legal to use proximity sensors within the robot perimeter. Teams have used optical and ultrasonic sensors in the past.

[engunneer]

Also note that the bumpers and the frame behind it aren't allowed to be articulated. That's not to say you can't figure out a way for them to be firmly mounted yet still work as a sensor, but you need to think about what you want to measure.

Are you trying to measure impacts, or just touched vs not touched?

You could possibly use an IR sensor or a range finder near the bumper zone, or possibly through the bumpers with a carefully placed hole, though I doubt that it would be reliable through the bumper. (Also have to check if it is legal)

[EricH]

Don't run it through the bumpers if you don't absolutely have to (and then only with the Q&A's clearance, printed out and brought with you to the event so that the inspectors know that this was declared legal).

Q&A already shot down a gap in the bumper so the camera could view the field. I don't think they'd be too thrilled about a hole in the bumper for a sensor.

[Kevka]

Originally Posted by engunneer

Are you trying to measure impacts, or just touched vs not touched?

The idea was to now, when the robot is crashing into things in order not to have it climb up walls (we had the problem during FTC that our robot would drive against a wall and then flip over).
I guess we will probably try distance sensors mounted a bit higher than the bumper. It will be harder to cover the whole width tough.

Thank you for everybody's fast reply.

[Al Skierkiewicz]

kevka,
Sensors mounted below the BUMPER ZONE but within the FRAME PERIMETER might work better to prevent the climbing you fear. However, I think the bumpers would prevent you from achieving the same response your FTC robot produced.

[Alan Anderson]

If the application is to prevent driving up a wall and flipping over, consider using a 2- or 3-axis accelerometer as a tilt sensor. If the robot reaches a defined angle (and you aren't intentionally driving over the bump), have it stop driving (or even drive the other direction until the angle comes back down).

[engunneer]

Ramming into a wall and flipping over is much less of a concern in FRC. Just make sure your CG is as low as possible.