Segway build.

[Wendelspanswick]

Thinking about it more, spur gears would be the ideal solution, minimal slack, chain will stretch over time so you will be having to adjust frequently.
If you do go with spur gears remember to reverse the motor direction!

 

[chunkolini]

Gerrymore,
You are a mad******, keep it up.
Next version needs a GSXR750 motor.

 

[gerrymoore]

Hi Chunko...yes I am mad...just like you!!! How was the holiday...a nice break I hope.

I'll build my next segway with an R1 motor...if you promise to test ride it!!!!

 

[Angusdog]

Next version needs a GSXR750 motor.

Wouldn't it need two, one for forwards and one for reverse? In theory...

 

[MattF]

A few hours in to the build (apart from the last couple of months designing!!) and I have a problem already.

In trying to get it to basically 'balance' without power - like a budgies toy - I've got the wheel sprocket too close to the motor sprocket and the chain doesn't connect with enough links - and will slip I think....as it has to drive both ways it needs to be as tight as possible.

I need to move the axle back in the chassis but have to talk with my programmer to see if it will effect the overall balancing.

Get the basic mechanics sorted and then worry about balance afterwards. You can easily add counterweights where necessary. Btw, (apologies if you've mentioned this elsewhere. I've only briefly skimmed the thread), is that standard mild threaded rod you're using for the axle? If so, that stuff won't last five minutes before it either bends or starts wearing through.

 

[gerrymoore]

Hi Matt...thanks for your input. To be honest, the actual 'balance' shouldn't matter as the electronics will automatically balance the whole machne and rider..it was mainly for moving it around when switched off.

The axle is stainless threaded rod and runs through bearings in the wheels...I think it will be OK..... but it's a prototype with a large learning curve!!

I've moved the axle point 30mm now and adjusted the motor mounts to give more movement for tensioning....chain sems to run smoothly now.

Motor dives are in now, complete with cooling fans, and the steering column bearings and 5k linear pot ready to be fixed.

Couple more bits and bobs and we should be ready for 'launch'...watch this space!!

 

[Wendelspanswick]

Arduino 'brain'?

 

[gerrymoore]

Correct...Mega, with an MPU6050 giro/accelerometer - not yet fitted.

 

[secretsmoker]

Wow this looks like a fun build. I have been racking my brain trying to think of some weldable Arduino projects but I am not that good with the coding so just stuck to welding cars for now. I only have the little Arduino board but it has already been in 5 or 6 electronicsy projects with sketches I downloaded.

Keep up the good work! Can't wait to see this taking shape.

 

[MattF]

How are you going to introduce some mechanical resistance into the steering column?

The axle is stainless threaded rod and runs through bearings in the wheels...I think it will be OK..... but it's a prototype with a large learning curve!!

Should last a bit longer then. I'd plan on getting that replaced as soon as though. You want a proper shaft in there. The stainless will hold up better than mild, but it will jigger the inner surfaces of the bearings like mad, plus at best the threads will likely flatten out where it passes through the bearings leading to slop.

Forgot to mention. You could also do with mounting those PCB's via nylon spacers or similar too. With them being fitted as they are, they directly transmit any twisting and shock in the structure to the PCB. You preferably want some type of anti-vibration mount there, which will also remove the direct solid coupling.

 

[gerrymoore]

Hi Matt...good few points there!! Will have to see about the axle..I have a small lathe so should be able to turn one easy enough. The motor drivers are bolted directly as their heatsinks need the chassis to dissipate some heat...but you're right about twisting to the pcb...mmmm. No problem mounting the Auduino and giro on nylon though.

The steering column will have two very strong springs to keep it centralised...not sure how much movement we need left/right yet though until the coding is complete.

Secretsmoker...yes, the arduino is a great little toy...the only thing I've made with it - apart from LED controllers - is a dawn simulater which works great in the winter to wake you up gently!!

There's a lot of code out there for whatever you want to make...check out the 'instructables' website for some ideas.

 

[MattF]

The motor drivers are bolted directly as their heatsinks need the chassis to dissipate some heat...

It'd be easy enough to pop them both on a separate chunk of heatsink then affix that to the chassis. How much clearance do you have where they're located, (width between batteries, height from chassis to axle, depth from front of boards to that other PCB behind them)? Might have some heatsink knocking about which you could use, depending upon dimensions.

 

[gerrymoore]

Hi Matt..thanks for the heatsink offer but I need to be able to replicate the build...leave it with me for now while I have a think!!

 

[outofthefire]

This might be a bit late but for some chains you can get a half link which might solve your problem of having to move the axle. If you have no way of adjusting the tension though you might want to consider using a belt drive rather than chain.

 

[gerrymoore]

Hi OOTF - I've sorted the chain now thanks. Moved the axle back 30mm to get a better angle over the tiny motor sprocket and have elongated the motor mounts so now got about 20mm of 'play' for chain adjusting. Powered the motors and they run cleanly.

 

[gerrymoore]

All finished ready for the code now. I've put the steering bar springs and control pot in now and made a lid. Eventually it will have a front and back plate too.

Have tried running up the motors and all seems OK with the chains now.

Won't have the finished code for a week or so - will update after the 'maiden voyage'.

 

[MattF]

Those springs ought be out front connected to opposite ends of a single pin going through the shaft. That way you'll have both springs working all of the time, rather than one being compressed and bent and one being extended. Plus, where they are now, it looks like there's a good chance of one of those motor wires being chafed by it.

 

[gerrymoore]

Hi Matt...wires are loose at the moment...once I wire them properly I'll make sure they're out of harms way.

No sure what you mean about the springs being mounted 'out front'? Any chance of a diagram as I would prefer both to act togther as you suggest.

 

[MattF]

Looking at that last photo you posted and using that as reference, a pin running through the shaft, (or a collar around the shaft, whichever method you prefer), horizontally just in front of that pillow bearing, on the same plane as the chassis. Then, the two springs secured at the front corners of the chassis, (roughly where your motor mounting slots are), hooked to the respective end of that pin through the steering shaft.

 

[gerrymoore]

Hi Matt...still not sure what you mean....doh!! Might be having a particularly dense day!! If the pin is, as you say, horizontal with the chassis then the springs are the same as before...one pulls and the other follows and vice versa....if the pin is vertical then each spring pulls the shaft which is then not vertical any more? Think I need a diagram...or a lie down!!