Electronic Shifting

[sam constable]

Hi Guys,

im looking into using an electronic shifting mechanism this year to replace our pneumatic system from last year.

im having trouble finding anything suitable so can anyone suggest companies that would produce this type of equipment please let me know

also if anyone knows anything to watch out for that would be great too

specs are listed as below:
- aprilia SXV550
- Required Stroke = approx 34mm
- required load = approx 6kg when static

thanks

sam

[sam constable]

Hi Guys,

im looking into using an electronic shifting mechanism this year to replace our pneumatic system from last year.

im having trouble finding anything suitable so can anyone suggest companies that would produce this type of equipment please let me know

also if anyone knows anything to watch out for that would be great too

specs are listed as below:
- aprilia SXV550
- Required Stroke = approx 34mm
- required load = approx 6kg when static

thanks

sam

[The_Man]

We used a Kicktronic gear change system on our car.
It is pretty reliable and produces more than required force. It was less expensive than the many of the other options available, but the weight of the system was slightly on the higher side(2kg I think). The size was also an issue for us, we had to move a lot of things around to fit it inside.

[Bus_Lengths]

(Hint: You aren't limited to devices that operate in a solely linear fashion...)

The purely electric device we are using on our car:
Weight: <24 oz (1.5 lb)
Cost: <$50
Force Applied: 182 lbs
Max Speed @ Max Force: 80 in/sec

On the stock length F4i lever arm, only 29 lb is required to shift. The incredibly excessive force is used to accelerate the shift lever/internals. The lever only needs to move about 1.1 in (rotate about 45*), so 80 in/sec is more than adequate excessively adequate.

Personally, I'd like to change the mechanical advantage to apply 400 lbs of force for more solid shifts, but unfortunately, our shifting device keeps eating the steel mounting plates at the current thrust level.

Total cost of this system was about 80 dollars and 20 hours of one of our teammembers time. And other than the constant yielding of our mounting brackets, it has been quite reliable and never needs refilling/recharging (and it doesn't leak).

[Lorenzo Pessa]

Our first car mounted an electrical actuated shifter on an Aprilia RXV550.

This kind of engine (the difference with SXV550 are minimal) is not "soft" in changing gear so expect to have a heavy system and mount a "big" battery (many amperes).

We shifted to a pneumatic system and it works better than electric.

[Lutter]

We bought a Pingel shifter this year. Haven't had a chance to try it yet.....

[RollingCamel]

If Honda gets its DCT in its smaller bikes.....

[Mehul Botadra]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bus_Lengths:
(Hint: You aren't limited to devices that operate in a solely linear fashion...)

The purely electric device we are using on our car:
Weight: &lt;24 oz (1.5 lb)
Cost: &lt;$50
Force Applied: 182 lbs
Max Speed @ Max Force: 80 in/sec

On the stock length F4i lever arm, only 29 lb is required to shift. The incredibly excessive force is used to accelerate the shift lever/internals. The lever only needs to move about 1.1 in (rotate about 45*), so 80 in/sec is more than adequate excessively adequate.

Personally, I'd like to change the mechanical advantage to apply 400 lbs of force for more solid shifts, but unfortunately, our shifting device keeps eating the steel mounting plates at the current thrust level.

Total cost of this system was about 80 dollars and 20 hours of one of our teammembers time. And other than the constant yielding of our mounting brackets, it has been quite reliable and never needs refilling/recharging (and it doesn't leak). </div></BLOCKQUOTE>


That looks good since we also use a F4i engine, an idea on the shift time? We're using a servomotor and are looking to shift to an advanced system. Shift time is a little issue with the servomotor.

[ToledoFSAE]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bus_Lengths:
(Hint: You aren't limited to devices that operate in a solely linear fashion...)

The purely electric device we are using on our car:
Weight: &lt;24 oz (1.5 lb)
Cost: &lt;$50
Force Applied: 182 lbs
Max Speed @ Max Force: 80 in/sec

On the stock length F4i lever arm, only 29 lb is required to shift. The incredibly excessive force is used to accelerate the shift lever/internals. The lever only needs to move about 1.1 in (rotate about 45*), so 80 in/sec is more than adequate excessively adequate.

Personally, I'd like to change the mechanical advantage to apply 400 lbs of force for more solid shifts, but unfortunately, our shifting device keeps eating the steel mounting plates at the current thrust level.

Total cost of this system was about 80 dollars and 20 hours of one of our teammembers time. And other than the constant yielding of our mounting brackets, it has been quite reliable and never needs refilling/recharging (and it doesn't leak). </div></BLOCKQUOTE>
Would you mind sharing a little more info on what you are using for an actuator? I wanted to do this last year to eliminate our CO2 issues. But I was unable to find an actuator that would work for our f4i (other than the beyond our budget Pingel). Everything was either not powerful enough, didn't have enough throw or needed ridiculous amounts of electric power.

Andrew

[RyMan]

It's a Dewalt drill.

[BrendonD]

Ha, I think Bus_Lengths was fishing for someone to ask what it was...

I would have guessed Craftsman, that way in case you break a drill, just re-assemble, go to Sears and get a new one.

Either way, it's fun and creative idea. Kudos.

[Chad Summey]

I am not a engineering student just a machinist. I would like to know how you drove the drill motor. How did you tell it to stop? Did you do this with the ecu? chad

[MalcolmG]

we used a dewalt drill motor for the last 4 or so years and just did it by having momentary switching via a pushbutton (controlling a relay which powers the drill), and the ratchetting mechanism built in to the bike gearbox only allows one gear to be shifted at a time.

If you retain the drill's torque-limiting clutch you can set that so it's only just strong enough to shift gears, this means that once the end of the shifter's travel is reached (i.e. the gear has been selected), the clutch just slips rather than the drill continuing to drive the shifter and potentially causing damage to the shift mechanism or overheating the drill motor or wiring.

All you're really doing is replacing the bike rider's left foot with a 4-bar linkage (or similar) connected to the drill motor

[Mikey Antonakakis]

Oh wow, now that's resourceful! Way to go guys.

[Kirby]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:
we used a dewalt drill motor for the last 4 or so years and just did it by having momentary switching via a pushbutton (controlling a relay which powers the drill), and the ratchetting mechanism built in to the bike gearbox only allows one gear to be shifted at a time.

If you retain the drill's torque-limiting clutch you can set that so it's only just strong enough to shift gears, this means that once the end of the shifter's travel is reached (i.e. the gear has been selected), the clutch just slips rather than the drill continuing to drive the shifter and potentially causing damage to the shift mechanism or overheating the drill motor or wiring.

All you're really doing is replacing the bike rider's left foot with a 4-bar linkage (or similar) connected to the drill motor </div></BLOCKQUOTE>

I have a photo of this from your 2006 design board! http://fsae.com/groupee_common/emoticons/icon_smile.gif

[ToledoFSAE]

Thats a great idea, cant wait to try it

[AxelRipper]

seems like a lot of teams will be investing in new cordless drills this year due to their old ones "disappearing"

it is a really good idea I must say.

[MalcolmG]

nothing new about it, I'm sure I've seen it discussed on these forums a few times.

To save you all some hassle, don't try to improve on the system once it's working. All attempts to make ours lighter/faster/smarter/prettier/better packaged over the last few years have resulted in a generally less functional/reliable package.

[Falcon™]

We have used a DC motor. Weighs around 2kg and delivers enough power for proper shifts.

Video of the same can be found here.
http://www.youtube.com/orionetrx#p/f/15/5RwhNBsvxsQ

[EHog]

This is so simple. I am furious at myself for not thinking of this earlier.

2 years looking for the "actuator from the gods", and no such luck. The answer was sitting in the shop the whole time...

Well, looks like we'll have a dewalt on either our 2011 or 2012 car...

[Tim.Wright]

We ran a dewalt shifter in '05. It was a 90 deg one so the packaging was really good and the shifts were quick but there are a few things to watch out for;

The current draw is massive since you are running the thing almost always at stall. So the clutch idea mentioned before is a very good one. I popped so many fuses we ended up hard wiring it in. Every shift we made dimmed the lights on our wideband sensor and set off error codes in our ECU.

Another thing was we eventually flogged out the bearings during the competition weekend and it caused the teeth of the bevel gears to shear off.

So yea, it will work, requires no extra power source, very little packaging room and it's reasonably robust.

Tim

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Timo:
We ran a dewalt shifter in '05. It was a 90 deg one so the packaging was really good and the shifts were quick

The current draw is massive since you are running the thing almost always at stall. So the clutch idea mentioned before is a very good one. I popped so many fuses we ended up hard wiring it in. Every shift we made dimmed the lights on our wideband sensor and set off error codes in our ECU.

Tim </div></BLOCKQUOTE>

What do you mean by "a 90 degree one"?

Also, did you ever try throwing in a decent sized capacitor to limit some of the transients?

[Tim.Wright]

by 90deg I mean the motor and the chuck are at 90deg to each other and driven by a bevel gear. I wont link a picture here since it takes too long to approve, but if you google dewalt 90deg drill your will find pictures on the first page.

Is very compact along the axis of the chuck since the motor and gearbox is in the vertical handle part.

The system was origainlly designed to run by a mosfet switching transistor array but after the 2nd or 3rd time it caught fire we hacked up a power circuit using only relays. Being a hack job, all subtleties like capacitors and clutches went out the window.

Also, finding a capacitor rated to store and discharge that much power would not be so easy.

[cjanota]

We ran a Bosch 12v drill for a year or two. Once we found a place to get the transmissions and the motors individually it was pretty reasonably priced (before that we had to buy the whole drill set from the store: drill, charger, 2 batteries, and the case ~$250) We now have 8 batteries and 4 chargers for the drill that we use in the shop.

You have to limit the torque put into the shift shaft (either by the drill clutch, linkage ratios or control logic.) If you don't this drill has enough torque to make the transmission shift when it doesn't want to. We did round off a set of dogs enough that it wouldn't stay in gear.

[BrendonD]

cjanota, where did you guys get the motors and transmissions for the drills? We're looking into this now due to some estimates of our steering input forces that may make a manual hand shifter a bit much to handle... PM me if you don't mind.

[cjanota]

I honestly cannot remember. I would look at sears to see if they can get replacement parts.

[John T.]

We have used a Translogic power shifter with are CBR 600 powered car for past 2 years, and its great.

Made in the UK, ultra light alloy, servo operated from two push buttons (up and down) and totally universal, designed for Drag Racing bikes and motrcycle engine powered kit cars. It can be easily mounted to any motorcycle engine, and comes with an M6 rod end on either end to mount it allthough we took the bottom one out and turned a bosss to fix the shifter to the bikes original gearselector rod and the top of the shifter off the rear roll hoop support . it worked great.

£670 plus £28.25 for over seas shipping

A little expensive but worth it. http://fsae.com/groupee_common/emoticons/icon_smile.gif


http://www.translogicuk.com/powershifters.htm


http://farm3.static.flickr.com/2439/3614485293_00d01ebbcf_b.jpg

[Mehul Botadra]

That is even more expensive that our new engine! :P

[Ockham]

Mate, that Translogic's more than a little expensive. Our motor with custom dry sump and aftermarket coils costs less than that. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

Gotta admit, that's a very slick system. Wonder where that linear actuator comes from...

If there are any FIRST Robotics veterans around here, troll your memories for good shift mechanisms. Many a clever device for very similar applications has come out of FIRST, and the parts are all over the place.