Seeking info about :: regenerative tech

[chapmanb@ku.edu]

I'm a student of industrial design at the University of
Kansas doing research for my thesis project for which I have chosen bike lighting technology(re)design.

Knowing that regenerative braking is incorperated into the segway made me think that pursuing an understanding of how it is implemented on a small scale could help me to determine if it would be appropriate to pursue for bicycle light power generation. The feasibility of this idea is mostly contingent on weight and final production cost.

I do not need to know exactly how to make it but more estimates of how much it would cost to develop. My ability to make a convicing case for the technology would be greatly enhanced by my understanding of how it could be pursued. I lack mechanical engineering knowledge but have taken engineering physics and calculus so I can understand a certain amount of technical information.

Relevant information/leads would be greatly appreciated.

Ben Chapman

e. chapmanb@ku.edu
tel. 1-785-979-5392
1015 missisippi apt. 8
Lawrence, KS 66044 USA

[citivolus]

Hi Ben,
I think it should do well. My guess, low cost to produce (even at low volumes), weight about 0.5 kg and retail around $50.

Here are some links to technologically similar items

http://www.smarthome.com/9288.html
http://www.campingsurvival.com/dynflaswitba.html
http://www.thinkgeek.com/gadgets/lights/5a9f/
http://www.onehitwonders.com/drf.html

good luck,

--
swiftly flying

[chapmanb@ku.edu]

Thanks for the reply! The technology of the products you sent me was helpful.

However, I'm interested in specifically how the energy recapture mechanism has been applied to the segway. I'm needing a method to create the most revolutions in a small dynamo from a very short burst of force (breaks being applied). Another problem being that the force involved is very intense over a very short time period which would definately stress materials in such a energy recapture device. The engineering prof. that I talked about it with was only able to suggest that I use some kind of a worm gear. I didn't look very much but he suspected that i'm using stock parts that it would be very heavy indeed.

[citivolus]

quote:Originally posted by chapmanb@ku.edu

..., I'm interested in specifically how the energy recapture mechanism has been applied to the segway.
It simply uses the drive motors as generators since they are constantly coupled to the wheels through the transmissions.
quote:I'm needing a method to create the most revolutions in a small dynamo from a very short burst of force (breaks being applied).
A small diameter friction drive directly off the tire would get a high rpm, be easy to mount and an activation switch would be trivial. It would always be driven by the wheel but wouldn't add much drag until the switch applied the generation load and hence braking force.
quote:Another problem being that the force involved is very intense over a very short time period which would definately stress materials in such a energy recapture device. The engineering prof. that I talked about it with was only able to suggest that I use some kind of a worm gear. I didn't look very much but he suspected that i'm using stock parts that it would be very heavy indeed.
Perhaps I'm misunderstanding the problem, is this for a lighting system for a bicycle? How much power are you expecting to generate? If this is for a lighting system, I would expect that 20 watts will be all you will need. The power requirements are such that it would be possible to simply drive a small generator continuously. A low power generator would add little braking force but could be used intermittently as required, be light weight and low cost. In general regenerative brakes are used because the equipment is already in the drive system and the implementation is trivial.

If you really want it to be an effective brake, calculate how much power is available assuming you can get 1/3 g deceleration from the device and base your stress calculations from that. The question will be what do you do with all the extra energy as a single stop will power lights for a rather long time and will require sufficient storage. I would avoid a worm gear in favor of a multiple stage spur or helical gear arrangement or even a chain drive for effeciency.

--
swiftly flying

[toybuilder]

Hmmm. I don't think recapturing intermittent braking energy with a small generator would provide enough charge to power a lamp for a significant length of time. I'm with citivolus -- I think constant application of a small generator makes more sense to me...

The other aspect of the design question is the cost of the generator. Segway motors would be too heavy and expensive, I think...

http://www.pasadenasegway.org/