E-Rockit

[Beeping-Sleauty]

interesting....if a trifle pricey....

BBC NEWS | Science & Environment | 'E-Rockit' hits German fast lane

 

[Rad]

Can't watch it because a)I have no sound on my work computer.
b)My boredband connection at home is not up to snuff.

It bugs the hell out of me that the BBC website assumes everyone in the UK has a 12 trillion MBS download speed so it's fine to just bung video content up with no text story as an accompaniment.

 

[wibble]

Can't watch it...

It's basically a fast ebike (80 kph). Nothing particulary new about that except the bike comes with pedelec and no throttle. So you're forced to pedal in order to make it move. It's designed to keep people fit, despite the fact that bike is so powerful that pedaling doesn't appear to take any effort at all.


The designer did seem a little eccentric. So say no more..

 

[Straylight]

I rather liked it But then maybe that makes me a little eccentric I wonder if you can set the resistance of the pedals, so it becomes an excercise bike on ,err, wheels. Actualy, I thought the guy just came accross as someone who was genuinely very enthusiastic about their product - quite a refreshing change from the cynical "only in it for the money" PR nonsense! And without such inventors we'd all be sitting in the dark, banging rocks together for entertainment....just a thought

I do like the idea of the pedaling cadence governing the throttle, rather than the torque approach though...maybe coupled with a thumb throttle on a HTP (highest takes precedence) basis, this could work for hub powered e-bikes. It'd certainly make for a more intuitive system than modulating the throttle whilst changing gears, all with the right hand. Excuse my ignorance if this has already been done BTW...

 

[Bigbee]

Can't watch it because a)I have no sound on my work computer.
b)My boredband connection at home is not up to snuff.

It bugs the hell out of me that the BBC website assumes everyone in the UK has a 12 trillion MBS download speed so it's fine to just bung video content up with no text story as an accompaniment.

Im at the end of the phone exchange and can only get 1/2 to 1 mb broadband at best,I can open and read that easily.If you cant there is some thing seriously wrong with your service provider and I would take it up with them or change to another.

 

[Straylight]

Yes, though I'd try to establish wether it's your line or your provider, if your sync speed is way higher than what you're actualy getting then it's your provider, and you can shout at them. Otherwise it's your line, and you should try BT (though I stress the word TRY).

If it turns out to be the provider, and they won't play ball, then have a go at making an official complaint via the internet sevice providers association: ISPA - Home, asthis usualy makes them sit up somewhat

Your sync speed is shown on your router's status page (if you have one), otherwise you can get an estimate of the pottential speed on your line here: BT: Broadband Speed Checker

Appologies for wandering OT....

 

[flecc]

Looks very much like a light motorbike with pedals to me, and obviously very heavy using motorcycle components.

Very illegal without moped registration etc even in Germany. I'd just buy the real thing if I wanted to travel like that.
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[frank9755]

Agreed - sounds like a minor cul-de-sac in the development of electric bikes but one that a reporter has spotted and attached too much significance too!

I didn't play the film but wondered if you got the full amount of power the moment you turned the pedals, or if there is some sort of torque sensor to prevent wheelspin and whiplash...?

 

[flecc]

It was on the midday BBC 1 news and it does have a torque sensor which is the only speed control. It was also registered with number plate so it needs the correct motorcycle driving licence for it's 50 mph capability.

The inventor seems to be beyond eccentric into nutter territory, advocating pedal control even in lorries!

All very silly, and the BBC's judgment is lacking in having it as an item for the middle of the main national news, not even as an "and finally" item.
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[Straylight]

As I said, the Cadence* controls the throttle, the faster it's pedaled, the faster the motor turns, and it's this I find innovative - don't you? I mean forget wether the overall concept is viable, that's in the lap of the gods/marketting/venture capital/consumer faddish interest etc., just because you may not like the package doesn't mean that all the parts of it are bad/illconceived.


* or is this what you mean when you use the term torque? As I always thought this to mean the force required to make a rotating object turn, not the object's rate of spin, such as when trying to ride up a steep incline in a high gear, the crank may not be moving very fast, but is experiencing high torque.

 

[frank9755]

As I said, the Cadence* controls the throttle, the faster it's pedaled, the faster the motor turns, and it's this I find innovative - don't you? I mean forget wether the overall concept is viable, that's in the lap of the gods/marketting/venture capital/consumer faddish interest etc., just because you may not like the package doesn't mean that all the parts of it are bad/illconceived.

Intriguing idea but I have to say my first reaction is that it sounds like he is trying to emulate the effect of not having gears, which seems strange. Bikes have gears because it is comfortable to pedal within a certain cadence range regardless of speed, so why would anyone want to neutralise that benefit?

 

[Straylight]

Weirder than that, it didn't seem to me that the pedals contributed to the drive train at all (other than as throttle control). Hence I said that it was akin to an exercise bike on wheels.

Now take this throttle control system and stick it on an ebike, and you maybe wouln't need gears at all, just a single freewheel sprocket at the rear? The only problem I can see is with regard to hill climbing, so you may well need two rear sprockets to compensate, but then the fixed wheel guys/galls have been riding like this for years.....hmmm, so maybe not a freewheel. Thoughts anyone?

 

[flecc]

* or is this what you mean when you use the term torque?

No, I meant torque, but I was guessing at it being torque control on appearance only.

Since as you say it's road speed is controlled by pedal speed I agree with Frank, it's very much the wrong way to go about things since cadence variation over a wide range isn't natural. There's wide variations on the cadences different people feel comfortable with, in general there's a tendency for the large and sometimes heavy to prefer lower cadences while the slim and athletic mostly like them higher. In addition low cadences below about 40 are damaging to knee joints when effort is applied, severe arthritis in the knee being cycling's most common permanent injury in later life. It's partly for that reason that race cyclists use high cadences in the 90 region to minimise damage while optimising efficiency. Cadences will frequently be very low on the E-Rockit with that control method and pedal effort applied in acceleration then will be very far from being a beneficial exercise.

Fortunately it will never catch on.
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[flecc]

Weirder than that, it didn't seem to me that the pedals contributed to the drive train at all (other than as throttle control). Hence I said that it was akin to an exercise bike on wheels.

It's difficult to tell from the video, but I think the pedal drive might be internal to link to the motor drive, or it might alternatively be on the other side from where we could see. The Swizzbee and the Izip Dolphin both use dual drives, the motor belt drive one side and the bike chain on the other.

If it is only an internal loading for the pedals and they don't drive the bike, it's even more crackpot!
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[Straylight]

Interesting, when I lived in London, I saw cycle couriers riding fixed wheel bikes, so there must be a market for it, if only a small one, and surely the power/cadence curve could be tailored, even switchable for the comfort of the rider, so they wouldn't need to apply a large amount of torque at low cadence. Something along the lines of the High/Low system that Wisper uses, or as I said couple it with a thumb throttle working on a simple HTP basis. My idea would be to simplify the machine overall, as we established that derailer gearing and hub motors are not completely suited to one another in the other thread.

 

[Straylight]

If it is only an internal loading for the pedals and they don't drive the bike, it's even more crackpot!
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Well, you could aways pedal a dynamo for the lights... Concidering the weight of the machine, and the power of the motor, I doubt that pedaling would contribute much anyway. I think that the core concept is to use the pedals instead of a hand throttle - which is what I found so fascinating in the first place.

So, does anyone know of a controler that can take a cadence sensor input rather than a throttle to guvorn motor power?

 

[flecc]

I think that the core concept is to use the pedals instead of a hand throttle - which is what I found so fascinating in the first place.

This is what the Panasonic system has done for eight years now, except that it uses torque pedal pressure sensing to decide the basic amount of power and cadence to tune that to fine degrees for the purpose at hand. Yamaha have now copied that system with some small differences.
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[flecc]

Interesting, when I lived in London, I saw cycle couriers riding fixed wheel bikes, so there must be a market for it, if only a small one, and surely the power/cadence curve could be tailored, even switchable for the comfort of the rider, so they wouldn't need to apply a large amount of torque at low cadence.

The London courier territory is mostly quite flat so fairly suitable for fixed gear riding, which has advantages in traffic conditions. However, the heyday of fixed gear cycling was pre-WW2, and once it was realised with time and age the knee damage that could result from low cadences, it dropped almost completely out of fashion. Sad to think that in those earlier cycling days cyclists were proud of how much force they could exert at very low rotations and boasted of long extremely hilly trips in that fashion, ignorant of how much they would subsequently suffer for it.

It would be difficult to restrict the pressure at low cadence by tailoring the motor response, since the rider would still be able to apply high pressure while the increased motor power accelerated to a higher cadence point. The joint cartilage only needs one rupture or displacement with bones touching to start the cycle of developing damage, so even intermittent instances of excess pressure would be harmful.
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[Straylight]

It would be difficult to restrict the pressure at low cadence by tailoring the motor response, since the rider would still be able to apply high pressure while the increased motor power accelerated to a higher cadence point.

Hence my suggestion of having a throttle on the handlebars to run in parallel, this way one could set off from a standstill with relative ease (though this could easily be a button with its own preset power curve). Of course it may not be suited to areas with a lot of hills, but may do well in other places such as EA & Holland. All it really means is better/cleverer programming of the controller - and in the 21st century, I'm sure we can manage that!

The interesting bit about a cadence proportional power system to me, and what caught my imagination in the first place, is that it would place very little stress on the motor/battery, and eliminate any sense for the rider of having to play catch-up with the bike. It also so appeals on the basis of its simplicity, and dare I say it, elegance.

 

[flecc]

The interesting bit about a cadence proportional power system to me, and what caught my imagination in the first place, is that it would place very little stress on the motor/battery, and eliminate any sence for the rider of having to play catch-up with the bike. It also so appeals on the basis of its simplicity, and dare I say it, elegance.

The excellent Panasonic system does all of this though, and gives more cadence flexibility.

The speed control by cadence is fundamentally flawed I feel, for the reasons I've given. In particular it's just not natural since as said, riders like their own preferred cadence and would not like to be forced into using an entire range of cadences to get different speeds.
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