Re: new project

I agree with Dave about the disadvantages of using steppers. They were my
first try for a micromouse, and it wasn't pretty. Yes, they were easy to
control, and driver dissipation wasn't much of a problem (I just used a
bunch of open-collector TIP120s on a pair of unipolar motors).

However, they sucked current like crazy!. And if they were turning fast
enough *not* to suck current, it was because the drive voltage was too low.
In short, they were just too big, heavy, and mostly inefficient. Plus, the
power/weight ratio was just too low to make a competitive robot.

DC motors turned out to be much better. They're available in such a wide
range of sizes, from tiny pager motors (that are really not very robust),
through camera drive motors (quite useful, although they require quite a bit
of reduction gearing), and on up to slot-car and RC car motors, which are
more than powerful enough for any practical micromouse.

Surprisingly (to me, anyway), they turned out to be easier to control, too.
Instead of pre-calculating how far to go, along with the
acceleration/deceleration ramps, I just used sensors to navigate (with wheel
counters as a rough approximation for dead reckoning). Much less software
overhead, and since I was using a lowly 8051 processor, many more cycles
available for maze solving.

Just my personal experiences. You might take a look at Peter Harrison's
pages at micromouse.cannock.ac.uk

--
Mark
"I prefer heaven for climate, hell for company."


"Dave" <dave.garnett@xxxxxxxxxxxxxxxx> wrote in message
news:1134122252_80037@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> <Keiichi.McGuire@xxxxxxxxx> wrote in message
> news:1134105352.368013.229890@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> or if i were to keep the stepper, what would be the advantage over the
>> DC motor?
>>
>
> This is probably a good point to suggest that you read a book or two. For
> instance "Building Robot Drive Trains" by Clark and Owings. Gordon McComb
> has also written a number of useful titles, and can often be observed
> lurking here ...
>
> In the end it all depends on whether you want to make your own basic
> mistakes, or stand on the shoulders of others and make some really
> interesting mistakes !
>
> Have fun !
>
> Dave
>
>
>


.

Relevant Pages

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