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Subject: 
re: What are you making?
Newsgroups: 
lugnet.robotics
Date: 
Sat, 7 Nov 1998 07:44:20 GMT
Original-From: 
martin.cox <xtr205958@xtra.co.^AntiSpam^nz>
Viewed: 
2303 times
  
I'm working on a mobile robot that has knobby tires but can still turn • about
it's center
(for easier navigation).  The idea is that the axle for each wheel can
rotate, so I can put
them at a 45 degree angle and 'spin' the robot around it's center.

Cool :)

It also going to give you a different sort of coordinate space and mapping
when it comes to the software. Something like rotate 37 move 300 rotate 60
move 400 etc... Have you a way of measuring absolute rotation? or is it all
relative to the current position?

Each
axle has it's own
motor and suspension.

So it works out about the size of a "bread and butter" plate?

I built a working prototype with micromotors, but
they weren't
strong enough to move the vehicle over even the smallest bumps.

I havent had one of these to play with yet. They do appear pretty weak.
What sort of rpm do they run?

The steering mechanism
worked though, so I'm planning to build one with the new mini-motors.

or four?

I also just ordered a 68HC12 board from Kevin Ross and I'm really looking
forward to
playing with that!

What's one of them do?

What type of steppers are you using (size and power)

Big old four wires ones I flogged from a couple of ancient mainframe
printers.

and how do you attach them to the lego gears?

Joy of joy, the shafts of the motors are toothed at about the same pitch as
Technics. I bolt technic beams to the motor's body and build from there.
4mm threads fine through technics or you can ream them to 5mm for a snug
fit.

I've used steppers in the past and enjoyed them, but I'm
not sure I want
to try to manage four of them at once!

Two is proving enough of a handfull. I'm finding the connection wires - and
in particular the actual size and number of the cables to be quite an
aspect to the design and it definately has quite an influence on the final
result

Cheers

=mjc=

#define :)+:) :)
#define ! NOT
#define KotSNAIL, 82 Ducati MHR, and Payer of its Speeding Tickets
#define FIAT850 Heart Transplant and Restoration Project
#define FOR.SALE Pininfarina Spider Classic Italian Sports Car & Barbeque



Message has 1 Reply:
  Re: What are you making?
 
(...) The base works quite well. I used NQCC to program the RCX and it now runs in almost perfect squares. Really cool. I'll have to do more with it later but this was a first stab at using NQCC (many thanks to Dave Baum for this gem). -- Doug (26 years ago, 9-Nov-98, to lugnet.robotics)

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