Team 964's Robit Thingamabob

[synth3tk]

Here's our robot, codenamed Applesauce, Applesauce, Applesauce. The grabber-type thing is only prototype, but most of it is being made with PVC and aluminum. Yes, it was thoroughly and rigorously tested to make sure that it withstands the wear-and-tear of the game. The electronics board you may see is not the final design.

http://www.bedfordrobotics.org/photos/IMG_1925.JPG
http://www.bedfordrobotics.org/photos/IMG_2084.JPG
http://www.bedfordrobotics.org/photos/IMG_2112.JPG
http://www.bedfordrobotics.org/photos/IMG_2183.JPG

Comments and questions are welcome.

Videos to follow as soon as I pull it off of both the camcorders.

[Jaybee1405]

Looks good. How tightly are you able to turn?

[synth3tk]

Looks good. How tightly are you able to turn?
Heheheheheheheheehe!!! HAHAHAHAHA!!!!! Silly student, tight turning is not important!!! Hehe!! Hardy har har. Haha. whoo. Turning. That's tight.

The proper response to your question is 'No'. Until we beat the programmers into setting up the foot pedal with sensitivity. Haven't gotten around to testing out on a partial field setup, but it does have the capability to turn pretty good.

[Jaybee1405]

I lol-ed

foot pedal? I believe that's against the rules (if you're serious). The rules allow the Operator Interface controls to include 3 things:
Things on the table
Things worn by drivers
Things held by drivers

[DarkFlame145]

Before they made size rules about OIs, 145 made an OI from the back seat of a van. You could sit there and the joysticks where mounted to the arm rests The next year there where size rules =P.

[synth3tk]

I lol-ed

foot pedal? I believe that's against the rules (if you're serious). The rules allow the Operator Interface controls to include 3 things:
Things on the table
Things worn by drivers
Things held by drivers
research. http://forums.usfirst.org/showthread.php?t=8176&highlight=pedal

We don't play when it comes to making sure it's legal this year. Looked it up during week 2. Nice custom assembly, some wood, a sensor or whatever it's called from one of the old joysticks. It works right now, but only in an all-on/all-off sort of way right now. Custom steering wheel to match, it'll be cool.

[synth3tk]

Ok, video is finally uploaded. http://youtube.com/watch?v=fcNEeOaIcVs

[Shivang1923]

Maybe it was a bad idea using turning wheels (left to right). Tank drive is so much easier to do. You guys kept hitting the wall, so I'm pretty sure that unless you guys get the hang of it soon, you should switch to tank drive.

[Daniel_LaFleur]

Rear wheel steering is difficult, and many times not very intuitive. It also looks like your fixed wheels have more traction than your turning wheels. Good luck working out the 'issues'.

[Greg Peshek]

Any particular reason you have to do rear-wheel steering? (At least that's what I'm guessing you're trying) And why you can't make the turning wheels the front? That's what we're doing with our Ackermann steering setup. Of course you'll still have the problem of not turning quite as tight as you'd like because it's not true Ackermann steering, but it should help.

If you have the programming capabilities I would suggest putting a potentiometer on the rack to sense position. If you have really have the programming capabilities it would be a lot easier for your drivers if the wheels would center themselves when you bring the joystick back to center, instead of having the wheels move when the joystick moves from side to side (essentially making your globe motor a large servo). We had the same problem as you, it being hard to control, but we are remedying it with the situation I just described.

Hope you get it working well.

-Greg P.

[SgtMillhouse648]

Haven't been able to watch the vid (dialup), but as for rear wheel steer, 648 did a 3 wheel tricycle drive for 3 years and it worked very nicely. The two front drive wheels were powered by the FP's, and the 3rd was built on a crab module kindof approach driven by a CIM and turned with one of the window motors. It could turn a full +-90, and the programmers programmed in an electronic differential to keep the wheels from slipping. As for driving it, we used a homeade steering wheel made out of one of the wheelchair wheels on a pot. Where the steering wheel pointed, the independent wheel rotated, and a joystick was used for purely throttle. It was an awesome setup, but we ended up ditching it for crab steer last year, and this year, I think we perfected it.....
Malhon

[synth3tk]

Ok, for those commenting about the turning and rear-wheel drive, thanks. Just a side note, that video is from the beginning of week three, so we've changed a lot since then. We'd already planned on adding potentiometers, which we did. Also a better steering wheel and pedals than the homemade set, but not because it didn't work. Just a bit easier on the hardware side.

Before the setup was this far, I had already grown accustomed to rear steering with an uncalibrated joystick. Originally the plan was to use it the other way around, but for some reason everybody found it easier to drive it this way. Still some testing needs to be done this week, but I think it's set now.

[Jaybee1405]

research. http://forums.usfirst.org/showthread.php?t=8176&highlight=pedal

We don't play when it comes to making sure it's legal this year. Looked it up during week 2. Nice custom assembly, some wood, a sensor or whatever it's called from one of the old joysticks. It works right now, but only in an all-on/all-off sort of way right now. Custom steering wheel to match, it'll be cool.

I stand corrected.

[Laaba 80]

From looking at the pictures, your trackball seems underinflated. You may want to add some more air.
Joey

[Qbranch]

I can't see any type of encoding/feetback device on your pinion motor for the steering. Is there any? If not, how are you planning on controlling your steering? (especially during autonomous period)

Our 2007 robot was originally going to rear wheel steer... but we did some physics work and found out that this configuration made the robot inhearantly more easily able to lose control and spin out at high speeds and intensive cornering. Just a warning.

Any photos/videos of your manipulator in action?

Looks good.

-q

[synth3tk]

From looking at the pictures, your trackball seems underinflated. You may want to add some more air.
Joey
I brought that up already. But everybody else in all their wisdom.....

I can't see any type of encoding/feetback device on your pinion motor for the steering. Is there any? If not, how are you planning on controlling your steering? (especially during autonomous period)

Our 2007 robot was originally going to rear wheel steer... but we did some physics work and found out that this configuration made the robot inhearantly more easily able to lose control and spin out at high speeds and intensive cornering. Just a warning.

Any photos/videos of your manipulator in action?

Looks good.

-q
I'm not of the mechanical-type, but I think we added a potentiometer for the steering? And we all seemed fine with rear wheel driving, although the robot was built where the tower could easily be flipped incase it was proven too difficult. Programming could be done between matches easily.

Uhm, for the manipulator, there was a slight miscalculation in the design so we had to redo the arm and tower. It might get mechanized before ship, who knows. Photos can be posted.