pic: Madtown Marauders DT of DOOM-1



Madtown Maruaders DT of Doom

This is a DT inspired by the Poofs/RAWC, Craig Hickman, and many other teams and mentors. Also this is a collaboration project with MORT team 11- the Marauders (lilstogi11) and us (team 1323)- MadTown Robotics. Due to the game clues and previous years, we wanted to make a DT that could climb ramps with ease and not tip while going up & down the ramps.

SO FAR:

We have the basic dt outline. All six wheels will be powered. The drivetrain drop idea is implemented into this DT along with suggestions from Craig on the gearboxes. The gearboxes weigh about 3.5 lbs with the motors and they have Delrin Plates. The front will be hinged and the piece to support it will be a 1/8” piece of 7075. The wheels are 4 inches in diameter and the clearance is about 1.5 inches. The DT will flex due to a gas strut. The hinge will have titanium shafts (Sunrise Medical, new sponsor, that will donate grade 9 titanium) and flex points will be reinforced. Both team’s drive train crews have put some thought into this and it has been given the OK from 1323’s engineers.

The Plan:

The gas strut will allow flexing in both directions. We have not included the motor that pulls the front up. But when you get next to the ramp, the motor pulls the front up (due to the fact that the motor has enough torque). Once you climb the ramp, the motor reverses itself and it lowers the front forward causing the bot to have all six wheels in contact with the ramp and helping the robot over the ramp. This way the robot never tumbles and it climbs up and down the ramp with ease. Vice versa when coming down. The DT at the moment weighs about 26 lbs without the CNC weight loss program.

Not included in the pic and need help on:

-Which motor to use for the lifting and how much force for the gas strut and the motor?
-Use chain or belts or spur gears to lift the front?
-Should the hinge use ball bearings or bushings?

When making comments please remember that this is a work in progress and that all of our design ideas are not yet included in these pics and that this idea is mostly just for kicks and is not intended to be used this year as a pre-determined drivetrain. It is just what happens when two kids get really bored on a Saturday night and use chat to talk from coast to coast. We have actually pulled out the old 06 ramps and looked at them. We used our old robot to visually demonstrate our ideas and it seemed to work out pretty well.

-RC and Akash ……EWCP

I was working on a DT like this a few years ago (right after the 06 season, I believe). Only mine had 8 wheels, and both ends folded up. They were designed for one specific angle, and pneumatically controlled. If they are used elsewhere on the robot (or if you just have the weight), I’d strongly recommend using pneumatics to lift the end(s) of the robot. The complexity of the system is greatly reduced (ya know, less parts there are, the less parts there are that can break), and there’s less stress in the system (you’re currently overcoming gravity AND the gas shocks). Plus, the time it takes to prepare for ramp climbing is greatly reduced.

If you don’t have the extra weight for the compressor, accumulators, etc, then I’d recommend either a belt driven system, or a spool with some sort of cable. Any motor could be made to do the job, it’s just a question of how fast or slow, and how much weight for gearboxes you have. The amount of thought required for the motor option is several orders of magnitude higher than for the pneumatic options.

As for the hinges… Bushings should be fine. The shaft in the bushings won’t be rotating too quickly, so they should have a sufficient lifetime. Also, there shouldn’t be much of a radial load on them, so they shouldn’t seize up while in use. Simple, but effective, IMO.

I’ve supplied a link to a few images of the DT I designed a while ago. It’s a smaller scale, and the outer wheels aren’t driven (though the large scale one I was working did have 8 driven wheels) . I didn’t put in the inner four wheels, but you can kinda guess where they would go. Unfortunately, none of the pneumatics are there or anything. But it looks cool. :smiley:

Folding Drive Train

i question the balance when climbing. i question the ratio of usefulness to effort. and i question ur face. otherwise i have no complaints =P lets do this!