[chbot] HBRobotics/Micromouse

Michael Pearce chchrobotics@lists.linuxnut.co.nz
Tue, 2 Jan 2007 18:55:43 +1300


I forgot the following...

Since you are stepping, you know exactly how many 
revolutions the wheel has done so you can calculate 
position easily. Using a standard 1.8degree/step motor you 
can easily calculate 1/200 of a rev using single stepping.

Using micro-stepping 1/200,000 of a rev is possible to 
determine (but not at a sudden stop)

Up Sides:
 1. Step counting for accurate positioning
 2. Easy to build basic drivers (Full and half step)
 3. High output torque (Can drive wheel directly)
 4. Instant stop and hold at current position
 5. Very repeatable.
 6. Easily obtained in old dot-matrix printers, 
    5.25" floppy drives and old hard drives (<200MB)


Down sides:
 1. weight
 2. power draw
 3. losing steps (if hardware design bad or running to fast)
 4. slow top speed  (but dont need gearbox)
 5. Not cheap to buy new compared to standard DC motor.
    

I may get stuck into my Pick and place project later this 
month, and will hopefully be able to demo it at the next 
meeting to show standard and microstepping techniques.


Mike


On Tuesday 02 January 2007 18:24, Michael Pearce wrote:
> That design is nice and simple.
>
> The steppers do have the advantage of being able to stop
> immediately, and have a basic stepping top speed of
> around 200 - 800rpm (higher if you microstep) and
> relatively high torque depending on motor choice.


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