Regenerative brake control

BenBenBen

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Joined
Jun 18, 2022
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Hello everyone,

Just starting this thread in // to my YZF built cause it more general and can be use for almost every EV.

Idea is to have 3 brakes commands on the bike. Mechanical front brake on the Handlebar Right side, Mechanical rear brake on the right foot, and regen' brake on the Handlebar Left side.

Regen, at list in my case, had to be controlled by a 0-5V input, just like the throttle.

I already prototyped a few systems using position sensors and it work, but the feeling is not natural, and almost impossible to control offraod when everything is shaking.

So I start a new prototype using an hydrolic clutch lever/master cylinder, an hydrolic tube (non aviation type) and a hydraulic pressure sensor.

So you can use this hydraulic lever just like a standard brake, and the harder you pull it, the more pressure you put in the hydrolic line, so the more regen you got from the controller.

For the moment, I turned a small adpater from brass that receive the brake fluid, holds the sensor and got a bleed screw at the end. (picture attached)

The sensor I used is a PX3 series from Honeywell that goes up to ~50bar pressure.
https://sps.honeywell.com/fr/fr/pro...ensors/industrial-pressure-sensors/px3-series

I took one I had in stock and modified the thread on the lathe to fit a G1/8 that I've got on the adpater.

Next steps:
- Test it on bench to verify that the 0-5V evoluates correctly with the brake lever feeling.
- Mount it on a bike and try to find a satisfying brake feeling in real life

Keep you informed,

Ben
 

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So you want feedback in the manual -throttle (of the potential regenerative breaks)? Or just a steampunk touch on you bike??

Question: Do you have a regenerative motor&controller now??
 
What I want is to have a regenerative brake that feel like a normal hydraulic brake when using it.

The harder you pull the lever, the more regen you got on the rear wheel.

With a brake power controlled by pressure on a lever, and not by a position like on throttles.

The thing is that I want to use it on an enduro bike.

Sometimes, you got long downhills where you just want to slow down. It that situation, regenerative braking is perfect cause it's a smooth brake + I get back energy for the battery. But on the other hand, on most technical parts of the track, you need to have no regen and just a fine control on the classic hydraulic brakes. In that situation, I'll just forget about this lever and drive like on a classic ICE bike.

I made a first bench test using an old front brake master cylinder and a 5V generator. It works well.

Voltage is 0.5V and stable when not touching the lever. then it goes up when pulling. You can go up to 4.8V when pulling really hard, but I think that a "normal hard braking" corresponds to about 3.5V. So the maximum regen power should be applied @ 3.5V.

Next step will be to mount it on a real bike with a hydraulic clutch lever and try differents tunnings until I got a good feeling.

It will take a bit of time cause I'm still building the bike, I keep you informed.

Video here:

https://youtube.com/shorts/P0kGNfl7yP4?feature=share
 

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BenBenBen said:
What I want is to have a regenerative brake that feel like a normal hydraulic brake when using it.

The harder you pull the lever, the more regen you got on the rear wheel.

While you can get variable regen braking, it doesn't work like that. The braking strength is proportional to motor speed, so as you slow down, it gets weaker.

Also, e-braking will be sensitive to lever position, not lever pressure. That's a very different dance. In principle you could have braking controlled by a pressure transducer, but I'm not sure how you'd implement that.
 
Chalo said:
BenBenBen said:
What I want is to have a regenerative brake that feel like a normal hydraulic brake when using it.

The harder you pull the lever, the more regen you got on the rear wheel.

While you can get variable regen braking, it doesn't work like that. The braking strength is proportional to motor speed, so as you slow down, it gets weaker.

Also, e-braking will be sensitive to lever position, not lever pressure. That's a very different dance. In principle you could have braking controlled by a pressure transducer, but I'm not sure how you'd implement that.

Yeah I know the way it works, an its realation with the motor speed.

But in any case, when you got a variable 0-5V regen input, the controller doen't care if it comes from a classic e-braking lever controlled by a position, or a pressure sensor like in my setupm. It just see a 0-5V signal.

The idea is to be able control the regen on a downhill to stabilize the speed (and so the motor speed of course).

So even if the braking power decrease with the speed, you got a feedback brake feeling from how the bike behaves and can adapt the pressure on the lever if you need more or less.

I already tried it with a position control on some bikes that uses a cable type clutch lever with a cable pulling the arm of a sensor liike the one in the picture I attached. This sensor generated the same 0-5V type signal that my pressure sensor.

It worked well, but the point is that when the bike is shaking a lot (often the case on offroad), the hand has a tendency to move and it modifies the regen level randomly. Also sometimes, the braking reflex pushed you to pull the lever straight to the handlebar with almost no effort which, at relatively high speed, generates a huge brake effect that can be dangerous.

Using this pressure system, I'm just giving the controller the same 0-5V signal input, but I control it with pressure instead of position witch is a lot more convenient for me.
 

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j bjork said:
It is just the same as accelerating, you just learn how much you want to twist/push even if you dont feel a difference in how hard.

That's exactly the problem for me. As historically "ICE bikes rider" I got this mindset like "manage a position to get power and manage a pressure to get brakes".

And I don't want to mix it up on the bike + I still got some ICE bikes and I'd like to have the same "principle" on all so I don't get lost everytime I switch... :D

If you want to try this pressure option, I can turn an adaptor and sent it to you with the sensor refenrence. Cause I won't be testing it in real life till my YZF isd not finished, and I'm quite far from this point...

I already tried a similar concept, a few years ago, on a DR 800 Suzuki I made. But it was working with a mechanical system with cable clutch, pushing on a pressure cell. Worked well, but too complicated and had problems of tuning and stability (cable getting loose, mechanism gettin locked etc...). So I finally just removed it and only used the 0% throttle automatic regen mode. It was a Dirt track bike, so brakes are not so much the point...

Here the bike:

https://thepack.news/80kw-electric-dirt-track-from-jambon-beurre-motorcycle/
 
I dont have much use for a setup like this at the moment.
Sadly none of my bikes have variable regen any more, because the controllers I have now dont support it :(

It will be interesting what feel you get in the leaver, I would expect it to be rather stiff and not move much?

That bike were a different creation :eek:
How did that chain line and single shock arrangement work out?
 
j bjork said:
I dont have much use for a setup like this at the moment.
Sadly none of my bikes have variable regen any more, because the controllers I have now dont support it :(

It will be interesting what feel you get in the leaver, I would expect it to be rather stiff and not move much?

That bike were a different creation :eek:
How did that chain line and single shock arrangement work out?

Never mind, just let me know!

Well that's why I use an cheap rear footbrake line and not a high quality avition type hoses. What you feel in the lever is, at the end, the elasticity of the hose. Feel pretty much like a classic front hydraulic brake. The end of the lever moves on about 2cm from when it stats to resist to max hand force (at list mine). But here you don't care so much about if the lever moves or not. The parameter is the force you apply with your hand and the braking feedback you got in real time. It would work the same if the lever didn't moved at all. maybe just a little less confortable and natural.

Yeh that bike was riduculous in many ways, but freaking cool!

The motor (emrax 80kw...) is actually attached to the swing arm; Which is actually the original Swing arm from the DR 800 that I turned upside down with the wheel to have a chain on the right side, and also reinforced strongly the area where the motor is attached so it don't twist with the single shock. I also reinforced the chassis for same reasons. The shock is from a K100 BMW designed to work as single.

Pack is a big box full of 6kWh of VTC6, that was affordable at that time!! . 28S20P Interesting cooling concept with air forced to a central hollow heatsink.

Worked well, even with the unsprung added weight that you don't feel to much cause it's really close from the rotation point.

Definilaty not gonna win a moto GP with this thing, but a ton of fun and massive accelerations.
 
Very cool idea, I am trying to implement regen on my next bike.

Aside, on the pressure sensor you choose.. What is the real difference? in the two? lol. Isnt 1-50 BAR the same as 15psi-700psi?

A nice turnkey lever that can plug in to a hydrolic system and apply 5v signal when needed is a neat idea.

The PX3 Series is available in two pressure ranges:


1 bar to 50 bar

15 psi to 700 psi
BenBenBen said:
The sensor I used is a PX3 series from Honeywell that goes up to ~50bar pressure.
https://sps.honeywell.com/fr/fr/pro...ensors/industrial-pressure-sensors/px3-series
 
DogDipstick said:
Very cool idea, I am trying to implement regen on my next bike.

Aside, on the pressure sensor you choose.. What is the real difference? in the two? lol. Isnt 1-50 BAR the same as 15psi-700psi?

A nice turnkey lever that can plug in to a hydrolic system and apply 5v signal when needed is a neat idea.

The PX3 Series is available in two pressure ranges:


1 bar to 50 bar

15 psi to 700 psi
BenBenBen said:
The sensor I used is a PX3 series from Honeywell that goes up to ~50bar pressure.
https://sps.honeywell.com/fr/fr/pro...ensors/industrial-pressure-sensors/px3-series

Yes it's the same thing with 2 different units. The changes inside this sensor series are the size of the mounting Thread ans the connection type. Bu they should all give the same output.

You right, an Of the Shelf version of this lever could be nice. Doesn't even need to be hydraulic. On my first concept, I used a force cell that is static. This kind of sensor can be integrated directly into the lever mechanism so it's compact and you'll never have leaks :)

I searched, but I didn't find anything like that yet. And it would require a lot more machining than this hydrolic concept which is almost only made of standards components.
 

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Hi everyone!

Just discovered today that this idea is actually not my idea!! Guys from Electric Motion in France already have a similar concept that they sell as upgrade part for their bikes.

https://haloa-emotion.fr/produit/electric-motion-poignee-prb-pels/

I'm not sure 100% but it seems to do the exact same job which is "convert a pressure to a 0-5V signal to control a regen' level"

So that makes me think that my idea was not so bad, and the way I make it work is about 10 times cheaper using just a second hand hydraulic clutch MC/lever, an old rear brake hydraulic hose and the sensor.
 
dominik h said:
https://endless-sphere.com/forums/viewtopic.php?f=12&t=113543#p1679616
https://endless-sphere.com/forums/viewtopic.php?f=12&t=113543#p1679616

In the rippy scoot thread a pressure transducer is also used

Right! I did tests with sensor mounted directly on the master cylinder like this, but I prefer the feeling with the "old non-aviation hydraulic hose". It gives some elasticity (spring effect) so the lever doesn't feel too hard, and it's closer to a brake lever feeling.
 
I implemented a torque sensor using a load cell, converting the Load cell signal to a 0-5V throttle input signal.
Some of that should apply to using it for a a 0-5V regen signal.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=94174&start=100#p1679413
https://endless-sphere.com/forums/viewtopic.php?f=3&t=94174&start=100#p1686510
 
scrambler said:
I implemented a torque sensor using a load cell, converting the Load cell signal to a 0-5V throttle input signal.
Some of that should apply to using it for a a 0-5V regen signal.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=94174&start=100#p1679413
https://endless-sphere.com/forums/viewtopic.php?f=3&t=94174&start=100#p1686510

Nice! Yes, but it's mecanically over complicated for regen I think.

I found an other guy that made a similar concept. It seems that he's got many DIY Ebikes and all equipped with this kind of regen brake control:

https://www.youtube.com/watch?v=lE7xfL1m2S8
 
Sure I was mostly thinking the amp board could be useful if you create a sensor with a load cell

I saw this one a while back that looks pretty good
https://hubsink.com/products/sketchbrake-cnc-variable-regen-ebike-brake-lever-caliper-disk-one-off-betas?variant=37997382536
 
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