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Old May 05, 2010, 01:02 AM
dammachines
United States, DC, Washington
Joined Feb 2004
1,398 Posts
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Just a Prototype - but I know you'll all hate it!

I'm sure I'm one of many who has one of these in the works. It's not really ready to be shown to the public, but with the other thread about electronic traction control I figured now was as good a time as any to share...

I accidentally had the gains on the balancing algorithm wrong during this video so it starting weaving when the speed got too high. It only took me a second to correct later in the day when I got to my computer, but I wasn't able to find anyone to help shoot more video. Maybe later this week.

The steering still needs work. I know what needs to be done, just need to find the time to get to it and the nice weather to test it. With the exception of the excellent CF Ricky frame and forks that I bought from Warren here a while back, I've done all the mechanical, electrical, and software design work on the bike myself...

Prototype R/C bike gyro removed plus rigid steering linkage (2 min 59 sec)


And though I'm doing a lot of testing on road, those here who know me know that I'm really only interested in off road bikes. It works quite well when the gains are correct. This bike's suspension needs some work because the front end gets quite bouncy as there is no damping.

Dave
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Old May 05, 2010, 01:39 AM
Registered User
United States, TX, Houston
Joined Jun 2006
293 Posts
I love it!!!

Just out of curiosity, what sort of sensors and microcontroller are you using? I'm trying to expand my system into steering right now. It currently just assists in controlling braking, limiting wheelies, and data logging.

-rskip
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Old May 05, 2010, 02:12 AM
I'm not totally useless..
radical ron's Avatar
Drunen. NL
Joined Sep 2003
407 Posts
I'm not for electronic wheelie/traction control ans stuff for road racing. But I do like the technology of the things that would/are possible.

Have to say your bikes riding looks really good allready. Especially for off-road bikes, you could eventually even remove the heavy flywheel if you get everything sorted. I will follow this tread with great intrest. Keep up the good work, very nice!!
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Old May 05, 2010, 03:19 AM
Registered User
indiana, USA
Joined Oct 2005
771 Posts
Dave I know you have spent alot of time and work on this concept, and I'm dying to see the video! but it's not loading for me. I was able to view other you tube vids so I'm pretty sure everything is good here on my end, I'll try it again tomorrow.
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Old May 05, 2010, 03:45 AM
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Dont ever apologise/if anything we thank those/you that inspire and commit to an idea! Im sure all of us are in admiration.
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Old May 05, 2010, 05:39 AM
AR Racing
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Italy, near Milan
Joined Mar 2005
930 Posts
Really nice project!

The problem is that for off-road usage you need more stabilizing effect that cannot be given from the light front wheel.

You can see it when you try it offroad.

Your next step, for offroad, could be to use a heavier front wheel, try to wrap some soldering or lead wire under the rim before installing the front tire.

Anyway you cannot drive offroad with a good gyro effect.

Keep us updated!

Ciao
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Old May 05, 2010, 07:59 AM
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Quote:
Originally Posted by Jena67 View Post
Really nice project!

The problem is that for off-road usage you need more stabilizing effect that cannot be given from the light front wheel.

You can see it when you try it offroad.

Your next step, for offroad, could be to use a heavier front wheel, try to wrap some soldering or lead wire under the rim before installing the front tire.

Anyway you cannot drive offroad with a good gyro effect.

Keep us updated!

Ciao
He means without me thinks?!
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Old May 05, 2010, 01:14 PM
Registered User
indiana, USA
Joined Oct 2005
771 Posts
The video loaded today with no problems.
Wow it's amazing how slow the bike was able to move and still remain upright!
I'm looking forward to seeing more of this project, keep tweaking those settings and the suspension and keep us posted.
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Old May 05, 2010, 01:34 PM
RC Dirt Bike Action
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California central coast
Joined Feb 2010
1,789 Posts
Beginning with bike going slow is great, the ending trying to ride off the curb, not so much hehe. Battery sideways is a little odd. I read bits n pieces elsewhere that you have no flywheel gyro in back wheel and its stabilized all electronically. Is that correct/still the plan? If so, very exciting. Glad to hear the bike would be more for racing, not that there is any, but its way over due around here. I wish you didnt have so many other things going on only so we can see it ready sooner.
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Old May 05, 2010, 06:44 PM
Bruce
Palmdale, CA
Joined Sep 2005
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Very nice Dave!
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Old May 05, 2010, 09:49 PM
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Joined May 2009
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is the steering link fully rigid?

if there's any hatred it will only come from those who are jealous.
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Old May 05, 2010, 11:48 PM
mp-
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Napa, California
Joined Jan 2004
706 Posts
The thing that's most impressive about this bike is the solid steering link. If you've ever hooked up a direct link from the servo to the triple clamp, then tried to drive the bike... Well, you know.

The mechanical engineering dept at UC Berkeley had a similar demonstration using a full scale bike a few years back. They had corporate sponsorship, the technical expertise of a team of programmers, mech engineers, machinists, thousands of hours of development, and untold thousands of dollars, etc.

Dave accomplished this by himself. Amazing. Can't wait to see what's next.

mp-
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Last edited by mp-; May 05, 2010 at 11:52 PM. Reason: info given in video title
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Old May 05, 2010, 11:56 PM
Editor, RCCA
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Joined Nov 2004
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Dave, as usual -- you rock.
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Old May 06, 2010, 12:51 AM
dammachines
United States, DC, Washington
Joined Feb 2004
1,398 Posts
Hey guys, thanks for all of the positive comments! I don't really expect this to be hated, but I know there are those who don't want to see electronic stabilization in their bikes...

Now to answer a few questions:

rskip -

I don't want to give away too many secrets, but I will say I'm just using a common 8-bit micro and the sensors are nothing fancy probably the same or similar to what you're using. I thought about adding a CF card for data logging , but instead I pump the serial output over an RF transmitter with the receiver connected to my PC. I posted an image of the "ground station" on another thread not too long ago. This way I can watch real-time what's going on with the sensors, where the bike thinks it is, etc. It's been very helpful with debugging.

I would think adding steering control to an on road bike with the usual dual spring setup shouldn't be too difficult (then again, I thought this was going to be a piece of cake also about 14 months ago.) The springs will allow the bike to balance itself, and a simple PID control should be able to handle steering to a desired lean angle.

As I've always intended for this to be used off road, leaving the springs in there was not an option. Without the momentum of a rear-wheel gyro to just power over the steering angle, the springs just won't work off road.


Antonio -

I certainly can't question the effectiveness of the rear wheel gyro for off road bikes. However, I fully believe that it is not necessary with this system. With the rigid link between to triples and the servo, increasing the gyro effect of the front wheel would just make it harder for the servo to turn it where it wants. I have driven it off road with much better performance than what is shown in this video. I'm still playing with the steering control and it was off a bit this day.

The front suspension on the bike I'm using is definitely a problem as there is no damping, and the springs are too strong for the weight of the bike.

Hopefully I'll be able to show better performance soon!


John -

Someday I'll find the time actually make the oil damped forks that I designed a few years ago. Funny that they end up being quite similar to the 1/5 scale shocks that someone posted a while back with separate compression and rebound damping adjustments.


JohnnyMc -

You know... I'm not sure what type of battery Warren designed this chassis to hold. I do have a 6 cell side-by-side pack that fits underneath w/o sticking out like that... it's just a prototype - proof of concept would perhaps be a better description.

There is no flywheel in the rear wheel, there are no springs in the steering linkage. There are a handful of sensors and a microcontroller to put all the data together and come up with a servo position that should balance the bike but also steer based on input from the r/c receiver. Way too much time has gone into the software that runs on the micro...

As far as jumping off the curb goes... I think if you consider the scale of the curb to the bike... and the fact that there is no rider on there to pull back on the bars (not yet at least) as the front wheel leaves the curb, it's pretty good that it stayed up upon landing... On the first one I didn't notice that the there was a dip in the dirt before the curb. With no damping in the forks the front end bounced up as it hit the curb causing the flip...


Torrance -

Yup, other than the play in the servo's gear train it's a completely rigid setup. It's actually pretty funny - long ago I thought I had successfully figured out the proper balancing algorithm - only thing was the bike was great at high speed, but horrible getting up to speed. It crashed a lot, but if I was able to keep it upright long enough to get to speed it was good. Turned out that the steering controls weren't working correctly at all... it was just all the slop in the first set of steering linkages allowed it to balance at high speed...


Patrick -

I was confused when I read the first un-edited message. Thought I was missing something! Thanks for the compliments. I really need to leave West Virginia and move out to the So Cal area where we can all collaborate and get our bikes out there!
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Old May 06, 2010, 12:58 AM
dammachines
United States, DC, Washington
Joined Feb 2004
1,398 Posts
Quote:
Originally Posted by mp- View Post
If you've ever hooked up a direct link from the servo to the triple clamp, then tried to drive the bike...
Funny you mention that... I was reading the part in the latest RC Car Action the other day where the article's author said that most people wouldn't be able to control an r/c bike without the springs.

I want to meet the person who can...
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