Custom 2 wheeled electric caster board

V

Vertigo

100 µW
Joined
Sep 28, 2015
Messages
8
Well, it’s not really a scooter and definitely not a skateboard but hopefully it will still have a place in this world!
This is my mechanical engineering design project partially inspired by boards like the dirt surfer.

Specs

• Battery: 10S 3P soldered from Samsung INR18560 25R cells (~260 Wh)
• ESC: the incredible VESC setup in BLDC mode
• Motor: Xnova 4025 560 kv 24 slot 8 pole
• Drivetrain: 2 stage gates GT3 15 mm width belts with roughly a 16:1 overall reduction (17:60, 26:120)
• Wheels: MBS Rockstar Pro for easy pulley mounting, 200 mm diameter tires
• Deck: 2x 6mm thick carbon fiber plates roughly 150mm by 600mm
• Frame parts: 0.5 inch thick 7075 aluminum
• Steering: 4 bar linkage based positive caster system (15 degrees of rotation in each direction)
• Mass: 6.7 kg or 14.8 lbs
• Top speed: calculated at 38 km/h or 24 mi/h
• Max gradient: calculated at 27% with my 70 kg mass
• Turning radius: not great, maybe 3.5 m
• Range: really depends on a lot of variables (read as haven’t tested yet)

Completely fabricated by myself with just a Shapeoko 2 CNC router and a drill press. Anyone can do it!
Still trying to find places to test ride it besides my apartment hallway due to the snowy northeast Ohio weather!
Renderings
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Holy shit!!! Any chance you'd want to sell me one of those chassis? Or a complete? I have billet 6" wheels that I'd love to do something like that with. I used to have a dirt surfer and miss it..

That is a beautiful design :shock:
 
Amazing design. I imagine it is very lightweight, the whole thing is literally filled with batteries. More photos and video please, this thing is fantastic! How did you bent aluminium?
 
Very, very impressed.
This thing is indeed a very beautiful design, I would be content just to put it on my wall and look at it. :shock:
I too would be very interested to know how you bent the aluminium so exactly.
Love to see more of this.
 
Don't have any plans to sell it, but more than happy to share the designs! There's already quite a bit I would change if I had the chance. Not to mention the fact that all of the aluminum parts required a great deal of filling and sanding in order to fit together properly. Probably would have taken 1/3 the time if I had used a proper CNC.

The steering concept is similar to a bike fork in the sense that the axis of rotation is in front of the tire contact patch so that there is a natural "trail" effect. But with the 4 bar linkage, the axis of rotation is an imaginary moving point rather than a fixed one like on a bike.

Oh, and sk8norcal, I've definitely seen that design! Very cool, but I'm not entirely sure how its steering works. Almost seems like the reverse of my approach.

Here's a clip of the machining on the 120 tooth GT3 drive pulley
[youtube]gwc05bidw7M[/youtube]

And I'm sure this isn't the kind of video you want, but this animation should clarify how the steering works
[youtube]4u-OKo16Mlk[/youtube]

More pictures, no video yet! My snowy excuse is in the background!

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Very nice! You sir are a doer:) Does the front wheel push towards the pavement when turning? I am building similar things. My goal is to use cad and cnc in the future but for now I am using a grinder and a drill:)
 
fascinating about the front steering but is it safe to drive?

what happens if it hits a bump and causes the front wheel to shake from side to side?

Does the front wheel return to center?
 
All I can really say at this point is that it works well in a straight line and seems to be more stable the faster you go. It's probably most similar to riding a bike without holding the handlebars. You just sort of lean and put your weight where you want to go. I'll definitely give a video update when I've had some more practice and good weather!

By the way Jan, you can do magical things with just a cordless drill and angle grinder. For this project I cut the hardened axles by chucking the stock in the drill and holding the grinder with a cutoff wheel against it! Makeshift lathe :)
 
How did you mill the copper sheet? Did you glue it to aluminium? What glue did you use and how did you remove it afterwards?
 
rmrf said:
How did you mill the copper sheet? Did you glue it to aluminium? What glue did you use and how did you remove it afterwards?
Click to expand...
It's just regular super glue. All you need is some heat to soften it up. I just threw it in a toaster oven at 350 F, useful trick!
 
Vertigo said:
It's just regular super glue. All you need is some heat to soften it up. I just threw it in a toaster oven at 350 F, useful trick!
Click to expand...
Great, thank you for sharing!
 
Hi,

Your design looks awesome!
How much did you spend for the parts of this masterpiece?
I would love to build such a board myself. Is it possible to get your construction plans?
As I don't know how to use a cnc machine I would have to outsoarce this part.
I'm sure you have more experience with your board now. Would be nice to have real life specs about top speed, range, max incline.
What about the stability and agility - are you happy with the result of your project?
What would you change?

Looking forward for news
 
It's been a while, but I thought I'd share the final draft of the research paper I made for this project. Probably more information than most would care for, but somebody may be curious!

Here's the link to download through my university:
http://ideaexchange.uakron.edu/honors_research_projects/352/

Just to clarify though, I'm done with this project and have no intention of making or selling the board. Would love to see spinoffs or improvements though!
 
Beautifully simplistic design!
Awesome report too! Hope you did well with that project.
Hopefully someone out there will run with it and prototype out some of your critiques.

Do you use it regularly?
 
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