172's built...a truck!

[K.Porter]

In it's current configuration, 172's robot looks surprisingly like a box truck...but the cool part is, it steers like one too!



Pardon the velcro'd electrical, battery, and tote of parts as ballast, as this is a very, very rough design. (it looks much neater in SolidEdge, trust me) But for a proof of concept vehicle, I must say this preformed rather nicely. Given 3 more weeks of frantic refinement, I say we might just have a nice robot.

[CyberWolf_22]

Is that a locked rear axle as in it does not have a differential. It still seems really cool. I also always wanted to see a team use the bins as part of their robot.

[Drew Hopman]

I LIKE IT!

that's awesome, i love the front wheel direct drive

only probs I can see are somebody smacking your front wheel while making a turn and the toughboxes get all screwed up

also, how do you plan on attaching a front bumper?

[K.Porter]

In our final design, we plan on shortening the front "yoke" piece, so that it rotates entirely (or almost entirely) within the confines of the frame. Essentially we plan to just shorten the assembly up, and drop the frame down around it for protection. (thus allowing front bumpers, more protection of the wheels/gears, etc)

The back axle you see there is simply some scrap lexan, a shaft we had lying around, and a pair of bearings. It'll be different.

Thanks for the comments!

[Jimmy Nichols]

Do you plan on any proportional control on your steering, or will it be full left and full right.

[Ross340]

What was that sound? I sure hope it wasn't your gearboxes. Eek.

[Steve_Alaniz]

Mwah haha ! You've tipped your hand!
I'm stealing your design!

YES!!!


Steve

[DarkFlame145]

very nice, but i dont think driving around the track will win the match. I really do like the front end steering though.

[Elgin Clock]

What are you using to steer? Steering wheel type system, or joysticks?

Very cool none-the-less. You may want to consider adding some rubber stops limiting your turning radius on the front though.

Turning that sharp at high speeds (which is certainly possibly with a 461 RPM speed of the Toughbox with the CIM) may result in some unexpected tip overs.

Very nice setup. Good luck this year!

Originally Posted by K.Porter

In our final design, we plan on shortening the front "yoke" piece, so that it rotates entirely (or almost entirely) within the confines of the frame. Essentially we plan to just shorten the assembly up, and drop the frame down around it for protection. (thus allowing front bumpers, more protection of the wheels/gears, etc)

The back axle you see there is simply some scrap lexan, a shaft we had lying around, and a pair of bearings. It'll be different.

Thanks for the comments!

sounds good!

do you have a potentiometer?

[K.Porter]

Okay...I was just out for a good 14 hours of robotics, selling FIRST to the Maine "STEM" (Science, Technology, Engineering and Math) group, so I'll try to address all of the questions/comments in order.

: Steering...currently, we're just using the standard skid-steer coding, but our programming team has all sorts of fancy scripts they feel like implementing. We'll probably stick to differential drive to turn, but the turning will be gyro/pot monitored and stabilized.

: On the sound...yes, unfortunately it is the gearbox. We machined custom plates...and, well, some of the novice machinists weren't as precise as needed. It's fixed now.

: ...imitation is the sincerest form of flattery!...

: On the "running the track" comments...the arm is currently elsewhere in the shop. You'll see soon enough... (not "just driving" for us this year)

: Rubber stops and limits are coming...probably springs of some kind too. Under full power, it can be quite a beast at the moment.

: And potentiometer; yes. That was tonight's job.

Thanks for all the comments again!

[DragonRagnarok]

As the programming team, I'd just like the make a little correction, we aren't using standard "skid-steer" coding. I had that for a day on the first upload, but it had since been modified when i took those videos. The yoke turns just from the differential motor speeds. the x-axis joystick reading has been cut in half so it turns nice and smooth. It takes a little getting used to to drive, but it looks much more graceful.

In the past I've always toyed with the idea of computer-assisted steering, fly-by-wire, etc. This drive train will very easily let me do this, along with the gyro a potentiometer which should be mounted tonight.

I've been thinking about working in a small dead-band into the x-axis of the joystick. As long as the stick is within the deadband, the robot will automatically keep itself perfectly straight. Even if knocked it could try to turn and resume the same heading. (Haven't looked to deep to see if that's actually useful yet, but it's a neat idea).

[edit] another idea is to use the pot to constantly read the yoke's angle, and use a USB steering wheel for added truck-iness. The potentiometer determines how long and in what direction to change the motor differential in order to keep the angle relative to that of the steering wheel.

[Qbranch]

Originally Posted by DragonRagnarok

[edit] another idea is to use the pot to constantly read the yoke's angle, and use a USB steering wheel for added truck-iness.

Neat idea for getting steering with minimal components, drives nice. One warning: watch out for the USB steering wheel that runs with the chicklet. It drops in and out of communication without much stiumulus, sometimes with (seemingly) none at all.

Cool drive!

-q