Welcome to Robot Dialogs. This is a place where I will record my progress, mistakes, errors, failures, lessons learned and hopefully occasional success in my designs and implementations of robots and other technical endeavors. I will try to make it as educational, informative and entertaining as I can...

Sunday, November 8, 2009

Change of Plans...

I've visited about 15 local hardware/hobby/auto parts/tool stores in the last 3-4 day looking for ideas and ways to turn these drill motors into drive motors for the robot. I've also logged about 8 hours of research into gears, gear types, gear ratios, and speed/torque conversions. I've decided to scrap the idea of using these motors as drive motors. The two main reasons are cost and unknowns. It costs as much to buy geared motors as it does to buy the gears to get these working. These motors are terrible as far as documentation goes. There's no way to find out their intended voltages, current draw, stall current stall torque and on and on... Because of this I don't know how far they need to be geared down. It would take some trial and error at my cost. I don't have the time or funds to do it. The other reason is complexity...It would take a fair amount of machining to create mounts for all the hardware in a custom gearing solution. Don't believe me? Have a look:

Every shaft would need a mount with precise holes, bushings (because bearings would be over kill) and testing. This kind of work isn't outside my abilities, I just don't have the right equipment... If I were still at school I'd just head over to the machine shop and make this stuff...unfortunately real-life means buying mills and lathes to do the work...I don't have the capitol for that yet.

In response to this I located an alternate motor source.
The site has been on my list of "places to try out" for a while so I'm glad to get the opportunity. This motor has good documentation for its electrical and mechanical characteristics and accurate dimensions. Meaning: I can design the mounts and electrical circuitry for them while they are in the mail. I also ordered a couple of tire hubs for this size shaft...should save some time. I really hope these motors were a wise choice.

The next post should have the motor control circuit, possibly the sensor circuits (I already know them, but it's good to draw it out still) and maybe some code :) . Probably have CAD drawings of the bot too...I've spent about 8 hours in Google SketchUp...I think I'm finally getting used to the controls...in my opinion they are harder to learn than AutoCAD...but free :).

No comments:

Post a Comment