Elec Engineer, RC Hobbist - need a better seq shifter

[Saf]

Ok its a bit OT on cars, its for my race bikes ... but it may also feed some other ideas perhaps.

I have a bit of a problem with shifting gears on my road and dirt race bikes, but have developed my own self sustainable seq air shifter setup, and on the road bikes, even my superbike for wanneroo, works flawlessly. I get lightning fast shifts at the touch of a button.

However on my mx bike i have a hard time hiding it, and its also draining the charging system. It doesnt seem effecient, and it makes me ponder that there IS a better way, something im missing.

To explain my system, i run a ARB 12v hi pressure compressor, thru to Norgren 5/2 pnueumatic valves and onto a pair of rams, back to back, one constantly extended, one constantly collapsed. The one that is collapsed expands to give me a up gear, the one that is expanded collapses to make the other motion, hence the down gear for eg. Confusing ?. Check it on my street bike ..

http://www.youtube.com/watch?v=bhFFtFok3DQ

And this is the setup on my CRF

http://img692.imageshack.us/img692/9489/001vxv.jpg
http://img704.imageshack.us/img704/1878/002yzd.jpg

Now onto the "what if" part. This system works superb, the shifts are super fast and perfect in that there is no missed shifts. I have tapped and setup the swingarm into a "tank" for the air, and between the forks in the front is a small surge tank that supplies a always ready on demand supply for a shift to the solenoids on the left of the pic.

So ... if i wanted to get rid of the pneumatic system totally, and run a elec ... does anyone know of any stepper motors, or hard core servos for buggies etc etc etc ?????? . Has to be durable, made to be water resistant, and be able to shift say 5-6kg of lever when under some load.

Any ideas out there ?

[ADZ]

Youtube link : http://www.youtube.com/watch?v=bhFFtFok3DQ

**edit: you fixed your link.. all good**

I've sent an email through to a few of my old elec engineering guys from uni to see if they've seen anything.

Has to be something better - That compressor just drained the bike in no time at all.

[Joe]

http://www.futaba-rc.com/servos/servos.html

Try the specs on the 1/4 scale high torque ones.. if the torque isn't sufficient, then you're shit out of luck with the RC spec gear.. as those Futaba's are as good as they get.

You'll have to go to a robotics spec servo.

[pazrs]

You could use linear actuators, but they aren't really design to stop at predetermined spots.

Other option and probably the most elegant is a big fuck off DC solenoid. It would be the fastest method and would not drain the electrics too much. Like these. (http://www.ledex.com/linear-solenoids/dc-open-frame.html)

[Lump]

u tube blocked here, so sorry if im on the wrong track, but might be hard pressed to find an electrical replacement for the rams.

bigger alternator or secondary battery maybe.

what about a mechanical drive compressor instead of the electric? that would be your best option i rekon

[devilfish]

Humm... doing it electrically is gonna be farking expensive, and i hope your good at programming! cos you'll need some control.

[Saf]

Adz, I suspect that the battery is tired ... because with the original setup on the onboard air comp resoivoir, it would do a shift, and then be on to top up. It would always run , and granted, it runs now longer, but can do 14 shifts between top ups. I have to buy another battery anyways, good to take a spare to the track.

Joe, Are they not too fragile you think ?.

Pazrs, I did have a look at some linear actuators after your post, have found some here and there, some high speed ones, but would have to run a pair, and its starting to get bulky. Been down the solenoid path, and its no go. The problem there is anything 12v only has a short throw, meaning you need to mount it much closer to the pivot point on the gear lever - much much more torque needed.

NWR, your quite right on the rams , they are so bloody good, and the speed of the shift is amazing. There is a uprated stator for desert racing (HID lights etc) but before i go down that path, id personally like to loose the compressor to begin with. No chance on the mechanical drive ... and there is no more room for another battery.

There has to be something ... im missing.

[stumps.]

excuse my ignorance , this looks amazing and well thought out so hats off to you there. But how come you dont use your foot?

[Lump]

NWR, your quite right on the rams , they are so bloody good, and the speed of the shift is amazing. There is a uprated stator for desert racing (HID lights etc) but before i go down that path, id personally like to loose the compressor to begin with. No chance on the mechanical drive ... and there is no more room for another battery.

There has to be something ... im missing.



sorry mate i cant see any other way, must be some way a mech drive can be used.
pneumatics are ideal for what your trying to do - if you need ~6kg of force compact electrics wont cut it.

how about an exhaust driven turbo to supply air pressure or divert exhaust pressure on braking lol

[Saf]

LOL, turbos eh ? :)

I have thought about running the system in Vac, as there is a unlimited supply by the motor. Again, not enough vac :(

I can go a C02 paint gun bottle, however this means i have a 1000+ psi bomb on board, and its non self supplying - need a few spares at any given time not far away.

The bottles are cheap from the USA, but its a PITA to refill always etc etc. The consumption from sound, is about the same on my 20mm ram to a paint ball gun.

Does anyone know how many shots you can get on a regular sized bottle ?

[Lump]

pump the air res up with diverted exh gas on braking, just need plumbing, tap (solenoid operated or by hand lol) & check valve :)

vac might work with a reservior but at full throttle you will be at atmo anyway anyway so might be hard to regenerate - also rams would need to be larger

[Saf]

No way will i be able to do anything with exhaust gas, the system runs between 100 and 120psi.

The vac would be easy. large tank (swingarm), and one way check valve between it and motor. But again, no where near the vac, and norgren have said that the solenoid valves arent designed for vac.

[Lump]

yeah i was only joking on the exhaust gas solution.
why isnt a mech drive for a small compressor an option? (i realise it sounds tricky to do tho)

[Saf]

The waterpump is on one side, the stator on the other .. neither cases (covers) could cater to run a link via belt to the pump, dirt, dust, water ... and then in the event of a crash, its just not something you can do with no external access to a crank.

[short-shift]

Front or rear shocks, by nature of action could drive a piston style pump ?

[ADZ]

excuse my ignorance , this looks amazing and well thought out so hats off to you there. But how come you dont use your foot?

He's spasticated.

Oh and in a wheelchair or something..

Found these - but goddamn they are ugly:

http://www.kliktronic.co.uk/technical.htm

http://www.pingelonline.com/eshifter.htm

Both electronic shifters.

[Lump]

The waterpump is on one side, the stator on the other .. neither cases (covers) could cater to run a link via belt to the pump, dirt, dust, water ... and then in the event of a crash, its just not something you can do with no external access to a crank.
what about a new/redesigned rear axle which has a gilmer drive pulley?
or similar on the gearbox output shaft?
not that familiar with bikes, so just throwing ideas out there

[AMPERAGE]

I'd suggest taking a look at a range of electronic actuators. You can pick up high speed and high strength models, are programmable both in speed and throw and can easily be set up to work with a lever type configuration to fit on a bike. Best of all, there are many types available in 12 and 24V models.

These are the sort of thing you'd need to look at.

http://www.intelligentactuator.com/rcp2.php

Bare in mind that you can get varying sizes, throw, speed, strength etc and you may need to do some research to find a company that sells exactly what you want.

[Lump]

http://www.pingelonline.com/eshifter_suzuki_gsxr.htm
http://www.pingelonline.com/eshifter.htm