Motor Controllers Donated

I’ve got a couple wheelchair motor drivers that I bought quite a while ago that I’ll donate. I’ve never used them but I’m pretty sure they are good for 40-50 amps. I’ll dig them out and get you the dimensions.

Ringo

motor controllers
Keith Rowell Design

Thanks for the controllers Ringo. I've shown them blocked in green. The size is 3.75 x 5.5" with a 1" guess at the height. Image shows relative size of motors to boards. Specs are here:
http://members.tripod.com/~divelec/hbridge.html

Axle Shaft Contributed

I found a shaft that may work well for the Mascot. I've included it in the following images. I'll bring the partial assembly to this month's meeting.

Mascot Parts list to date:

Motors with gearheads___________________________Mike Lynch
Shaft, bearings, wheel locks ______________________Keith Rowell
Motor controller boards __________________________Ringo

Mascot Parts wish list:

wheels
frame material
power
controller
sensors

Images of Shaft, Bearings, and Mounting Hardware

bearings
Keith Rowell Design
The bearing OD is 0.688"
I have 5 of them and expect to use two per wheel which leaves one spare. This configuration should allow all the weight from the shaft to be carried to the wheels with minimum friction.

friction locks
Keith Rowell Design

I have 4 friction locks but we may get away with using only 2. They consist of a split sleeve that is threaded and a nut. Tightening the nut locks the location. They fit the shaft perfectly. They're currently attached to a larger OD metal tube and will have to be cut off. I'm looking for volunteers who want to cut these, I think a lathe will be required.

22 3/8" wide
Keith Rowell Design

I found a nice ground stainless steel shaft that may suit the mascot's needs. It's only 22" wide so it should make it through most doors easily. The OD is 0.311". I have bearings and friction locks to match the shaft. These all came from an old pen plotter so they're quite fine.

4' high and rising
Keith Rowell Design

I added a virtual box to represent the posible body mass of the bot. This gives a proportional reference as to the scale of all the parts togeather. Shown here the bot is 4' tall and 22" wide and deep.

new shaft and bearings
Keith Rowell Design

The bearings I have are mounted in these very convenient brackets. There are 5 of these as well. The brackets are aluminum. They're only shown as an alternate. If we mount the wheels on bearings, the shaft doesn't need to turn and won't need bearings at the frame mount.

First part for the AHRC Mascot drawn

Mike's Motor

This motor is from a child's ride on toy car. Mike can correct me but I think it's 6volt. It looks like the minimum wheel size is going to have to be 6-8". The rib is there to support weight, so the robot frame should go there I guess. We should do some tests on the motors to see what their power characteristics are.

Ringo volunteered a motor driver circuit that is more than powerful enough for the job.

I think the 4 main design objectives for a "club mascot" should be:

1. light and easy to transport
2. big for visual impact
3. flamboyant, showing off, technological cleverness to be proud of
4. cheap, cheap,cheap


Pretty much all development ideas are graded on these criteria, meeting three is pretty much a shoe in but very rare. Hitting two of them is very good indeed. It's always a trade off. While formulating your ideas about how we should develop our "design by committee", think about these objectives.

Everyone's ideas and input are vital, don't hesitate to comment. Your opinions drive the design process. Vote early, Vote often.

I expect the process to take about a year to complete from idea to working bot. The process I envision is an iterative process where I take the comments and sketch them in and present them back. We can go through alot of options this way quickly. Lets give it a try...