<<  <  Page 4/5  >  >>
User Rank
ChasChas   2/15/2012 9:36:02 AM
The advantage I see over other attemps is that it keeps chain efficiency and appears to keep the weight down - the two biggies - efficiency and weight.

Matthew Stout
User Rank
Re: Additional Sensor
Matthew Stout   2/14/2012 10:24:05 PM
I like this idea a lot. It is a flaw in the current system that you must change speed in order to shift in some ways, because when climbing up a hill you may want to still be in a lower gear. It would also be cool to have more manual inputs in the system. For instance, ideally if you could push varying setting for normal, hill, racing...etc on the bicycle's control box that would be very useful. These setting could have different programming for gear changing and utilize different sensors. That way you could put in an sensor for incline without forcing the rider to utilize this if they just want to go up the hill slowly. I actually considered doing this as an input function, but the programming would have been much more longer and complicated for this application. If I was going to actually market this product, I think it would be a great idea. 

Matthew Stout
User Rank
Re: Could be a bumpy ride
Matthew Stout   2/14/2012 10:07:26 PM
I agree with you that our design would not be good for racing, because it is meant for a person who wants to just have a comfortable ride to school or to work. Many basic level riders do not shift enough or shift too much. And most people riding their bike to school or work do not need all of the 21 speeds (or whatever) the bike offers. So this system utilizes four gear sets that are spread out over possible gear ratios in order to select a good gear for the speed of the rider. I understand the concerns about smoothness and that is something we tried to address, but of course it is difficult to address every riding conditions. So the compromise here is that you don't have as many gears for a varied amount speeds, but you also don't have a bicycle that is shifting constantly. If you really get pedaling quickly (as I even tested), the bicycle will skip shift steps (due to the timing of the program) if needed. Also to address comfort, we made the upshift different from the downshift for each gear. So even with a lot of variation in speed close to a shifting point, you won't get redundant shifting. Also, the movement of the servo motors is very quick (and since it can move both gears at the same time) it is actually quickier and equally as smooth (since it uses the same derailuer of the manual shifting bike). And the shifitng only occurs when the pedaling is constant in order to get smooth shifts. More of the features in order to improve smoothness and the ride are in the paper. Thanks for your comments and interest. 


User Rank
Re: Could be a bumpy ride
MYRONB   2/14/2012 7:11:04 PM
Neat idea, but maybe in the abstract, not in a practical sense.  As a long-time touring bike rider and trainer of the 1984 USCF National Womens Criterium Champion, an automatic shift is the last thing one wants for touring or racing.   Quite often it is important to anticipate what gear one wants to be in for an expected situation.  Typically, one selects a gear  to suit the terrain, wind, and pedalling cadence a rider can maintain.  Riding in a pack of other riders, whether racing or touring, also affects the choice of  ratio desired.  No thanks, but I think KISS is the best.

Regards,  Myron Boyajian

User Rank
Additional Sensor
Nugent_56   2/14/2012 4:51:11 PM
I think a sweet addition would be an inclinomter to measure the angle of the grade, so even if the rider doesn't slow down that much, it would still downshift to give the rider more torque to handle the hill.

User Rank
Speed sensor vs power output sensor
rickgtoc   2/14/2012 4:09:28 PM
Neat demonstration project.

I think, however, power output of the rider would be a better measure than speed, albeit more expensive to obtain.  User selects an upper and lower output range, and tranny controller adjusts to maintain.  There are cycle computers out there that measure output, so it's probably possible, although more complicated.  Of course there is another complication to be handled.  You don't want the bike to shift while the rider is cranking down hard on the pedals.  The audible "tranny controller suggests a change" melody would be a signal to the cyclist to ease up for the shift.  If the system senses the ease in pedal pressure, then the shift occurs.

Next challenge: a cyclist airbag system for falls and collisions.  And it has to weigh under 3 pounds.

Jeff Martin
User Rank
Would have done stuff differently.
Jeff Martin   2/14/2012 3:41:32 PM

rcservosdon'trespondtoadutycycle. theyrequireacontrolsignalwithhasapulsewidthofmin1mstomax2ms.  thena40msorsodelayuntilthenextpulseout.  theangleoftheservowillbeproportionaltothat1mspulsewidthwindow.

theycouldalsobenefitfromapotadjustablecomparatorforthewheelspeedsensortosetthethresholdofthestripdetection. thiswouldalsosquareupthereoutputsignal. iwouldalsothinkthatyoucouldsetaninternalforeverloopsetto.25secondsinainterruptserviceroutine. whileintheloopyouwouldcalculatethewheelspeedbylookingatacountervalueandresettingonceperloop. ithinkthiscouldhaveallfitonjustonepic.


User Rank
Now if we could only make the CYCLIST user friendly...
oldtimer8080   2/14/2012 3:32:18 PM
The other problem that needs a solution in the many mountain trails in CO is the mountain bike operator.

On the roads and trails close to Golden, abuse of the trail privileges by speeding cyclists have had the effect of RATIONING the times mountain bikes can be ridden on these trails.

If the people riding concentrate on THEIR " Share the Road " responsibilities, rather than changing gears, then this would be a win-win for the other people and animals using the trails and roads.

If this encourages the " darn, YOU spilled my latte by using the trail while I was on it " crowd, then this setup is a step backward.

For me, adding a Golden Motors Magic Pie motor was the real system that made my Corsa HPV useable up here.



Rob Spiegel
User Rank
Re: Yes, but…
Rob Spiegel   2/14/2012 2:35:49 PM
This one comes pretty close to reading the mind of the cyclist. Perhaps even closer than the automobile's automatic transmission. I wonder if this will make it easier to drink coffee while cycling. The automatic trans in the auto certainly helped me in that area.

User Rank
Yes, but…
RobLewis   2/14/2012 11:40:11 AM
There have of course been several attempts at bicycle automatic transmissions, but I don't think the problem will truly be solved until somebody comes up with one that can read the mind of the rider.

<<  <  Page 4/5  >  >>

Partner Zone
Latest Analysis
During a teardown of the iPad Air and Microsoft Surface Pro 3 at the Medical Design & Manufacturing Show in Schaumburg, Ill., an engineer showed this "inflammatory" video about the dangers of maliciously mishandling lithium-ion batteries.
The Window Watcher stops the burglar before he does damage or enters the house. House alarm service companies set off alarms and call the service only after the burglar has damaged and entered the house.
If you’re designing a handheld device or industrial machine that will employ a user interface, then you’ll want to check out the upcoming Design News Continuing Education Center course, "Engineering Principles Behind Advanced User Interface Technologies.”
Brooke Williams of Texas Instruments explains how TI’s new TDA3x chip will help future vehicles “see” all around themselves.
It's been two years since the Mac Mini's last appearance on iFixit's teardown table, but a newly revised version joins Apple's lineup this week.
Design News Webinar Series
10/7/2014 8:00 a.m. California / 11:00 a.m. New York
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 20 - 24, How to Design & Build an Embedded Web Server: An Embedded TCP/IP Tutorial
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: 10/28-10/30 11:00 AM
Sponsored by Stratasys
Next Class: 10/28-10/30 2:00 PM
Sponsored by Gates Corporation
Next Class: 11/11-11/13 2:00 PM
Sponsored by Littelfuse
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service