Here's a bike shock system than can be controlled -- soft or rough.
Jason Brack and his fellow Colorado State engineering students, David Dang and Broc SommerMeyer, created a magnetorheological (MR) bicycle shock absorber that can be adjusted using a touchscreen to affect the bike’s ride. The MR fluid reacts to a magnetic field. In this case, the viscosity can be increased or decreased to change the dampening rate of the shock absorber. Using the touchscreen display, the user can select the ride quality of the bike.
Here is the touchscreen mounted on the bicycle.
The ride selection screen helps you pick your ride quality.
Rob I'm noticing a stream of Colorado State University engineering students developing some really cool and innovative gadgets. This is the second bike gadget I've seen from the university where the first one was a Smart Bike Shifter (Gadget Freak Case #205). I assume biking must be big in Colorado, based on the bike submission projects, along with skiing. Cool Gadget!!
Yes, biking is big in Colorado, especially in this age group. And yes, we are seeing a string of projects from Colorado State. That goes back six or seven years. What I'd like to see is a string of your students, MrDon.
Rob, I'm still working on the sales pitch of the benefits that come with submitting projects to the magazine. Some of the students are interested but trying to put this project into their busy schedule.
Rob, Another reason for my students to submit their projects to the magazine. Gadget Freak provides hands-on, real world experience for the students base on their submitted designs to the magazine. Yes, it does provide a nice item to include on their resumes.
It is nice to see students working on such an innovative and useful product, to be able to make the damping of shocks variable can be of great use in applications other than bicycle as well. It can become a basis of advancement of automotive industry as well. A great idea.
This is a nice gfadget, but I would have used a different user interface. I would be nervous about the screen on the side of the bike. A blue tooth connection to a cell phone app would be more appropriate.
naperlou, I agree. Its a very nice device but the TFT screen being exposed on the side of the bike allows it to be damaged quite easily. The screen could have been mounted on the handle bars and using a wireless connection, such as BLE (Bluetooth Low Energy) the controller can communicate with the mechanics (MR shocks). Still an impressive device.
Thanks for the comments. We wanted to control this with a cell phone, but decided it might be beyond our abilities. This was pretty much our first experience with control systems and we wanted to make sure we didn't get in over our heads.
Jason, You guys did a great job on the bike project. I do understand about being over your head when developing products. I tell me students not to get caught up in the tech glitz -glamour of the project but focus on the team's capabilities to accomplish the individual tasks required to complete the final product. Very nice work!!!
mrdon: I completely agree about getting caught in the glitz etc. and no substitute for hands-on-experience. I would bet a majority of students would be more interested in producing a Zoom -Pow video with exploding bikes and a rock soundtrack rather than this straight forward: Here it is approach. Many would volunteer for the video, few will be willing to give up time for the bike. Just look at some of the elaborate pranks and tricks on various social media web sites.
Tool_maker Thanks for the confirmation. Your correct about how social media has an impact on educational endeavors. Maybe the key to increasing active educational participation is to allow total student ownership of the video production. In addition to creating the product and engineering documentation, the students will be involved in the planning of the video recording/production. Hopefully, this hands-on involvement will promote active participation among the students. Hopefully!!!
Unfortunately, that was my point. You will have a plethora of students who want to make the video, but very few who will want to work on the bike. However, as you state letting the students take ownership yields much more positive results.
When I was still teaching and I assigned a research paper, I never received near the quality as when it became an I-search paper for which the student could choose their own topic, do first-hand interviews and experiments and report their findings and failures. (That was hard to convince students that what did not work can sometimes be as valuable as what did work.) One of the best papers I got came from a very hard to motivate student who wrote an excellent paper, complete with illustrations, on the evolution of hockey sticks. He wrote a ton of letters, received enough responses from players from different eras that he gained sufficient knowledge to produce a quality paper.
What was really cool was that I seldom had to direct the students to get back on task as each was anxious to get to work on their project.
This is a way cool gadget. It's a lot more sophisticated than any of my projects. I'm sure this is just a prototype to demonstrate the concept, instead of a finished product. Otherwise, the control panel would be in a much more convenient place.
Another thing: Will the iron particles in the shock oil not eventyally grind down the metal parts? I've heard of this technique before in a clutch used in an automobile AC system. Also, how much power does this thing use? A big battery or generator would slow you down a bit, wouldn't it?
You're correct that this is just a concept. The power requirements are probably the main hangup, because we needed around 10 amps to get a good response.
The iron particles are 325 mesh (44 microns) and are at least theoretically coated in a surfectant that acts as a lubricant. Current commercial applications of MR fluid appear to have pretty much overcome any abrasive qualities.
Guys, the correct iron powder for MR systems is spherical and under 15 microns (even better under 7 microns). Two companies, BASF and Ashland make iron powder from a chemical process that meets these specs (these two companies also sell powder that is already annealed). It has excellent magnetic properties if the carbon is reduced (removed) by an annealing process. The spherical shape allows even a rare earth magnet to activate a shock. The MR shocks use nothing close to 10 amps. The small iron powder flows through very small orifices so the switching does not have to be great magnetic flux if your path is small.
Previous poster said it well, this is a combination of mechE, EE and chemistry among others.
Now, finding the right software control logic is your next big task!
Thanks for the information on what iron powder would work better. The professor we talked to about the MR damper conversion said almost any iron would work but the smaller the better.
The draw back to this design and the difference between production MR dampers is the coil placement and the field direction. For optimal results the coil should have been located internally, closer to the valve and around the small ports. The magnetic field needs to be normal to the flow direction to cause a drastic change in the damping being developed, which only occurs at the coil entrance and exit. To get enough damping change we had to run very high current through the coil to make it work and locate the coil exit close to the valve. If we could have done all of that then we could have made it much more compact and run it on little to no power. We didn't have the time in a 3 month project to completely re-engineer the shock and then modify it to work in that manner.
I am happy to hear that you have done some thinking about possible design improvements. I realize that a perfect product cannot be made in such a short time. Iterative development processes are much better and let you learn and develop a "feel" for the relative importance of the various factors that influence performance. It would be nice if you had time and resources to make version 2.0. Good luck.
What about magnetic damping, where a strong magnet moves through a coil of wire? A shorted coil would be solidly damped, like a shorted generator. You would change the damping factor by varying the resistance across the coil. You could use a bridge rectifier and a MOSFET as the variable resistor. Better yet, two series connected MOSFETs with their gates and sources tied together. It would take almost no power to control the damping factor. You could run the controller for a long time on a 9 volt battery.
Keeping in mind that the temptation for students is to overreach what they are able to do in the course of a class because of all of the options that are available - I think they did a fantastic job and they kept the project achievable. While I agree that the placement perhaps needs to be redesigned, I view this as I would a working prototype and no doubt the students involved learned a lot about multiple disciplines during the course of their work. Bringing a project from design to completion is no small task and I applaud their efforts.
Just curious. What are the majors of the students who participated? Also, how did the idea for this project come about? What was the deciding factor in picking the Arduino board versus maybe a Beagleboard?
All three of us who worked on this are mechanical engineering majors. None of us had much experience with electronic gadgets, so a lot of the decisions we made were based on very little information.
As far as entirely magnetic damping, we didn't really consider that very much. At first glance I would think that it would be difficult to generate enough field to support the impact forces generated on a mountain bike. I guess I need to do more research now!
As this appears tto be an engineering project developed by some college students it may well be that the problems and shortcomings were of greater benefit than the pars that might be termed successful. For them to look back and see what they didn't know and what could have been done better they will become much better engineers.
Because of energy requirements this might not be a practical application of this technology, but it is a much more responsive test bed that a heavy automobile might have provided. and I am sure that there are many more questions that could be asked. Like how will those iron particles affect the small orifices over time and might it be necesary to use carbide or other hard material to limit wear?
And as to why they used an Arduino - Probably because they could afford it... Another one of the constraints on an engineer. Can it be made? And can it be made within the budget? And now can you make it for less?
I love the design and concept...I just wonder. Is this not already being done in cars today? Or is this transfering that tech to bikes? Love to have my motorcycle realize I am coming down from a 50 foot launch and readjust the suspension for me!
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