Segway clone project motor choice help

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CometBoy
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Segway clone project motor choice help

Post by CometBoy » Sat, 18 Aug 2012, 22:18

I have been playing with Segway style PT devices originally styled off the book Arduino Robotics by John-David Warren. I have now built two prototypes and learned much in the process about self balancing platforms.

I am now looking into a third “Seg-Bot” version and need help in choosing the best affordable motors for the purpose.

I currently use wheel chair motors (with their standard worm gear reduction boxes) and find even after rebuilding the couplers that the inherent backlash is a problem. These are obviously not designed for such continual forward/backward movement.

For the next version I was thinking about using hub motors with a wheel diameter of around 17 or 18 inches. I would appreciate input from people that may have experience using such motors. One concern is the need to run them forward and reverse.

After learning more about the genuine Segway, I fully know the limitations my third version will have but these things are the ultimate geek challenge.....

See Project Details Here

Thanks

Bruce

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Sutho
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Segway clone project motor choice help

Post by Sutho » Mon, 20 Aug 2012, 20:38

Nice work!

CometBoy
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Segway clone project motor choice help

Post by CometBoy » Tue, 21 Aug 2012, 11:16

Thanks,

Fun stuff.....

My main concern is that many Hub motors seem to have gearing internal to get the desired speed for the wheel diameter and hence this might have backlash?

Secondly that If I go with BLDC Hub motors that they don’t like being reversed quickly?

But I have no experience with Hub motors so not sure......

Bruce

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Sutho
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Segway clone project motor choice help

Post by Sutho » Tue, 30 Apr 2013, 21:38

elmex wrote: This power then drives the electric motor. With all these types, they connect the engine to a propulsion propeller or screw through a drive shaft. Inboard boat motors started out with steam engines. It evolved through two-stroke and four-stroke gasoline engines.

Thanks.


I've seen this type of contribution to forums before. Generally people trying to get their credibility up so they can embed links for SEO purposes.....eh elmex?

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Richo
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Segway clone project motor choice help

Post by Richo » Wed, 01 May 2013, 05:45

Maybe it just got lost in translation.
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Canberra32
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Segway clone project motor choice help

Post by Canberra32 » Thu, 02 May 2013, 13:59

What about large stepper motors off say a CNC router?
My router runs back n forth no prob :)

CometBoy
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Segway clone project motor choice help

Post by CometBoy » Thu, 02 May 2013, 18:51

Thanks for that....

Re stepper motors:

I guess I was worried about the step angle (the ones I have in the workshop are 1.8 degree) causing a jerky feel. Especially as I want to direct drive the two motors to the two wheels (16” to 20” diameter).

But may be worth a try?

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Johny
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Segway clone project motor choice help

Post by Johny » Thu, 02 May 2013, 20:11

CometBoy wrote: Thanks for that....

Re stepper motors:

I guess I was worried about the step angle (the ones I have in the workshop are 1.8 degree) causing a jerky feel. Especially as I want to direct drive the two motors to the two wheels (16” to 20” diameter).

But may be worth a try?
I'd be careful about having enough rotational speed with 1.8 degree steppers. There will be a limit to how fast you can drive each phase to get some RPM out of them. Other than that, the "step" effect should not be very obvious as the tyre compound will cushion the drive component. Then of course there's torque. Steppers get weird when you drive them outside their ability to keep up - with no feedback.

CometBoy
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Segway clone project motor choice help

Post by CometBoy » Fri, 03 May 2013, 20:08

Yes I agree the Stepper Motor concept is not ideally suit to this job mainly for the reasons you state.

So I’m back looking at using high powered brushless motors, essentially AC synchronous motors with permanent magnet rotors. I would like direct drive so the hub style has the most appeal. I have read that quickly reversing these is an issue so I guess the only way to actually find out is to get a cheap Chinese setup and test it. I see some of the newer wheelchair designs are using what appears to be high quality brushless hub motors. Also not totally ruling out old school brushed DC either but they seem harder to find in hub motors now.

Any views appreciated....

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Segway clone project motor choice help

Post by Canberra32 » Sat, 04 May 2013, 03:00

I have to say that the old stepper off my CNC seems to be doing very well on the kids gokart is smooth and though it gets warm it seems ok to me. It's just a 1/4hp one 110v
The CNC now runs 1hp units but it dose cut faster than most routers I have seen :)

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Segway clone project motor choice help

Post by Crash » Wed, 10 Jul 2013, 06:13

I wouldn't be suprised if some of the motor controllers that are available have features in them that create problems with torque reverse to motor direction, also they can have a bit of cogging at slow speeds which may interfere with the segway balancing algorithms but would be interested to see how you go if you try them as it certainly makes the design simpler avoiding chain or belt drive systems. Are you just planing to use the arduino to give inputs to the BLDC motor controller throttle input or are you planning to run an arduino bldc motor controller board?

Also there is an instructable done by someone from Scitech in Perth about making a Segway chair. They use a couple of cheap brushed DC motors from Oatley Electronics.

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