PMW Shocker

General Discussion about large electric scooters and motorcycles and other things with no pedals.

Re: PMW Shocker

Postby liveforphysics » Sat Apr 11, 2009 11:09 pm

I'm confused a bit with the dampener method used in these rubber designs. Getting the wheel to move up and down and behave like a spring is the very simple and definately not the goal of a suspension system. Giving the wheel the ability to move the wheel when needed to keep the bike platform stable, and then NOT behave like a spring afterwards is the big trick to good suspenion (aside from rigidity of course).

The goal is not to mount tires onto the bottom of a pogo-stick, you would handle much better a rigid bike.

I must be missing some critical element that prevents them from behaving like a rubber band.

Can anyone help me to better understand?
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Re: PMW Shocker

Postby Miles » Sat Apr 11, 2009 11:16 pm

Well, there there is some internal damping when using rubber as a spring. Also, the lighter the unsuspended weight, the less the level of dampening required....

The Moulton New Series bicycles use a fluid damped conical rubber suspension unit, for the rear suspension.
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Re: PMW Shocker

Postby northernmike » Sat Apr 11, 2009 11:31 pm

Wow, Greeves bikes are shockingly nice...

Image
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Re: PMW Shocker

Postby Sheriff Jon » Sat Apr 11, 2009 11:44 pm

liveforphysics wrote:I'm confused a bit with the dampener method used in these rubber designs.


It is quite simple really, not all that hard to figure out. It is very much like the link that Miles put up except on my Hoverboard the large tube is square and the center arm is diamond shaped and it uses 4 rubber compression rods instead of three. I don't know 'why' it works as well as it does, but it does. Perhaps your confusion is because you are over complicating matters by trying to compare it to more complicated suspension systems with their inherent strengths and weaknesses?
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Re: PMW Shocker

Postby northernmike » Sun Apr 12, 2009 1:19 am

Image

Hoverboard 1.0

No CIDLI. :shock:
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Re: PMW Shocker

Postby liveforphysics » Sun Apr 12, 2009 6:05 am

I don't have any trouble seeing how it can behave like an elastic material, and cause the suspension to follow hooke's law and behave like a pogo stick. No trouble seeing the function of the spring portion of the suspension at all. I'm puzzled about dampening.

Now Miles said the Moulton uses a fluid in a cone shaped rubber piece to behave as a dampened spring. I could definately see this working, and working very well for low travel quanities with a low frequency of actuations.

However, something with 12" of suspension travel, moving at 60mph across rough terrain dumps and increadible amount of heat energy into the shock oil. So much energy that large aluminum tubes in the path of strong air flow get too hot to touch, and overheat. Everytime a fluid damper functions, it functions by time shifting the kenetic energy release of the energy stored in the spring that absorbed the bump. This process works by internal friction on a viscous fluid being made to transfer from one chamber to another through a small orifice. The internal fluid friction energy is huge to be able to dampen 12" of wheel travel. At speed over rough ground, it easily becomes thousands of watts of thermal energy, which is why the entire fork tubes get burning hot/overheat etc. This is because time shifting the kenetic energy on the forks return travel inherently involves a lot of energy conversion with high fluid friction losses between each step.

How does this bike's dampener system function, and transfer the waste energy by product of functioning away from the thermally sensative elastomers? I think he said, no fluid, no seals, no stiction. Does this also mean no dampening? Or if the dampening is internal to the elastomer, does this mean dampening for 30seconds at a time at speed on rough ground before the temperature exceeds the plastic zone on the elastomer? How does he reject the dampener energy and internal friction from an elastomer without fluid?

If the suspension is 12" travel without dampening... That's seems criminally negligant to put on something capable of high speed offroad use. 60mph trampoline. All it would take is hitting a set of dips spaced at the resonate frequency, or multiples of it, and the machine will loose control and wreck. Doesn't matter how good you think you are, taking a bike offroad that is out of shock oil results in a prompt loss of control. Dampening, rigidity, and geometry are the keys to suspension function. Take away any of them, and you took away the ability to control the bike effectively.
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Re: PMW Shocker

Postby Miles » Sun Apr 12, 2009 6:18 am

This is quite a good summary of the Moulton car suspensions:
http://www.miniweb.org.uk/mainPages/alexMoulton.html
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Re: PMW Shocker

Postby michaelplogue » Sun Apr 12, 2009 6:25 am

I'm just theorizing here - But the compression/heat phenomenon is not just a one way street. Decompression has the opposite effect. So - in theory at least - one should end up with a zero net change in temperature.
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Re: PMW Shocker

Postby liveforphysics » Sun Apr 12, 2009 7:19 am

Compression and Decompression of a gas, yep. For most things, it's internal friction of deformation both ways, but with some energy absorbed in the relaxing state, but certianly a net gain of energy from internal friction.


However, again, I'm not concerned with the spring function, or the energy absorbed by the spring function. It's the dampening that I don't understand. For example, in a standard fork, it's over a liter of fluid in each leg, with a piston and internal seals. The piston is on a rod with an orifice, and a needle/seat valve to regulate the useful diameter of the orifice. When the fork compresses, it has to accelerate fluid to a high speed and move it through the orifice into the other chamber, then on it's return path, it has to go back. Each way the fluid gets accelerated to high velocity, and this internal friction of the fluid is what provides the energy absorbtion medium to time delay the return of the stored kenetic energy in the springs of the fork. Otherwise it would be a pogo-stick with a wheel on the bottom, and you would be better off and much safer with a rigid fork.

The spring function of suspension is very simple, and I understand it well. The dampening function is where ALL the design work occurs in making a shock, and it's what has the biggest impact on the way the suspension behaves. Just a few ticks on the clickers to adjust the dampening (spring rate stays constant), and the whole attitude of the machine changes. I'm not saying he needs adjustable dampening or raceing adjustments and things. I just want to understand the mechanism that causes the dampening to function in this design, and how the thermal energy by-product of dampening is dealt with.
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Re: PMW Shocker

Postby huskydave » Sun Apr 12, 2009 11:56 am

It seems to me that because you have a pivit point you would require a much smaller, shorter shock for dampening because the arm acts like a lever. I think a small shock on the end of the lever mounted above the torsion box world work great for dampening.
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Re: PMW Shocker

Postby PatmontS » Sun Apr 12, 2009 12:53 pm

Luke,
Thanks for the excellent and pertinent questions.
The compression and damping on this CIDLI suspension system is both bench and field tunable for desired performance characteristics over the 13.5" of travel front and rear.
As there are sensitive patent and trade secret issues in that area, suffice it to say...if we tells ya more we gots ta kiiillls ya.
Yes, shockingly we have eliminated the heat generation always found with traditional high performance, high travel suspension systems.
If you're able to make it to Minden in beautiful Northern Nevada we'd love to get an unbiased opinion of the prototype's capabilities from an expert with no "skin in the game". We assume you'd have no problem with the usual NDA formalities concerning these and other not yet disclosed but equally shocking details contained in this forward looking project.
Sincerely,
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Re: PMW Shocker

Postby PaulM » Sun Apr 12, 2009 4:32 pm

huskydave wrote:It seems to me that because you have a pivit point you would require a much smaller, shorter shock for dampening because the arm acts like a lever. I think a small shock on the end of the lever mounted above the torsion box world work great for dampening.


The overall energy to absorb does not change. A small damper like this would have an even harder time to get rid of the heat.

PatmontS wrote:Yes, shockingly we have eliminated the heat generation always found with traditional high performance, high travel suspension systems.


Shocking indeed. With all the hype this "Shocker" is getting, I will be shocked if it ever sees the light of day. Surely the Japanese will buy the project and mothball it to keep it from embarrassing their own machines.
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Re: PMW Shocker

Postby huskydave » Sun Apr 12, 2009 9:31 pm

I will wait to pass judgement until I talk to someone who is unbiased that rode this bike and tested it properly. The forces on the frontend are the same but at the end of that lever it requires less energy to dampen it much like a rear suspension on a swingarm. The arm acts like a lever you don't see 2 15" shocks on the rear of a bike because the swingarm transfers only a percentage of the actual force on the bike to one small shock that can handle the forces. This design will imo transfer less force past the pivitpoint. Will it work in realworld conditions? who knows but I think it has potential.
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Re: PMW Shocker

Postby PaulM » Mon Apr 13, 2009 5:36 am

huskydave wrote:The arm acts like a lever you don't see 2 15" shocks on the rear of a bike because the swingarm transfers only a percentage of the actual force on the bike to one small shock that can handle the forces.


The swingarm is amplifying the force seen by the shock. That is why the spring on a rear shock is many times heavier(stiffer) than fork springs.
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Re: PMW Shocker

Postby liveforphysics » Mon Apr 13, 2009 6:07 am

PaulM wrote:
huskydave wrote:The arm acts like a lever you don't see 2 15" shocks on the rear of a bike because the swingarm transfers only a percentage of the actual force on the bike to one small shock that can handle the forces.


The swingarm is amplifying the force seen by the shock. That is why the spring on a rear shock is many times heavier(stiffer) than fork springs.



That's right. You can make the stroke displacement that the shock body itself moves be 1mm or 1m, but the force changes by the same multiplier, so the energy is the same either way.

Lift a 10lbs weight 10ft, or life a 100lbs weight 1ft, and the energy is the same.

The energy in this situation it determined by the weight on the wheel, and the amount and rate that it moves. No matter how you configure the linkages, this is still he amount of energy the suspension deals with.
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Re: PMW Shocker

Postby liveforphysics » Mon Apr 13, 2009 6:33 am

PatmontS wrote:Luke,
Thanks for the excellent and pertinent questions.
The compression and damping on this CIDLI suspension system is both bench and field tunable for desired performance characteristics over the 13.5" of travel front and rear.
As there are sensitive patent and trade secret issues in that area, suffice it to say...if we tells ya more we gots ta kiiillls ya.
Yes, shockingly we have eliminated the heat generation always found with traditional high performance, high travel suspension systems.
If you're able to make it to Minden in beautiful Northern Nevada we'd love to get an unbiased opinion of the prototype's capabilities from an expert with no "skin in the game". We assume you'd have no problem with the usual NDA formalities concerning these and other not yet disclosed but equally shocking details contained in this forward looking project.



Absolutely fantastic that the dampening is both bench and field tunable. I draw lines and put letters on the tops of my clickers with a sharpie. A spot I like for technical woods riding (W), a spot I like for jumping(J), and a spot for high speed baha action (B). That way I can spend 30 seconds and dial the bike in to be better suited when the terrain or riding style changes. Definitely not much fun to try to jump when you tuned the bike for woods LOL. :)

I will gladly take you up on that kind offer. If the machine can survive me, and my 30lbs over my old raceing weight body, I think it's a form of certification. You can rest assured 99.99%, maybe even 100% of the electric bike buying demographic will not be able to break it. I will gladly write an unbiased review of the machine that you can choose to use to help give people an idea of how the bike feels and performs.

At this moment, I still have a couple broken ribs and a broken bone in my left foot (highsided at 50mph :)). I'm still riding, and it doesn't really bother me much, but I'm not quite at 100%. It would be better for me to wait at least 2 weeks so my body will be ready for riding at full strength.
Last edited by liveforphysics on Thu Apr 23, 2009 1:33 am, edited 1 time in total.
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Re: PMW Shocker

Postby PatmontS » Mon Apr 13, 2009 12:47 pm

Luke,
We look forward to your evaluation.
I'll stand by for your PM here on this forum to set up the visit.

fechter wrote:Very impressive specs, Steve.

I'd be real interested in hearing more about the motor and controller....



Thanks fechter for those kind words. We're humbled that you too have expressed interest in the electro motive aspects of the Shocker prototype.

As Altrex does not yet have DC brushless controllers, we're using the 500A controller with regen presently available from Kelley. Though it doesn't have as many programmable features that Altrax offers, it's working fine for now.

As we want the machine to be suitable and reliable for mud and sand conditions, I can divulge that the motor is sealed .
It also has very low centrifugal force as the heavier windings are fixed. The lighter magnetic rotor allows for a bike with very light handling feel in tight maneuver situations, and enhances the machine's impressive acceleration capability.
We went with a liquid cooled motor, but may be able to significantly reduce cost, weight and complexity by eliminating the cooling system with 12V coolant pump.
The motor is mounted to the rear swing arm where a traditional shock absorbing system would otherwise have been located. This allows for a lighter, simpler and quieter single stage reduction system and creates a low slack, constant chain length geometry without the need for noisy chain guides. It also raises and protects the chain from "casing" events and other obstacle interference. The motor location also accommodates lower battery pack placement which results in a very low CG.
It's trippy watching the up and down action of the rear wheel while the motor moves simultaneously for and aft (however with much less travel).
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Re: PMW Shocker

Postby liveforphysics » Mon Apr 13, 2009 1:54 pm

I'm very much liking the constant chain length :) The sealed up motor is also very slick :)

My E-bike uses a 20Ah 74v LiPo pack capable of 25c continuous, and 30-35c burst. I've been plagued by controller problems, because my big Kelly can't run the motors to peak RPM, so I've dumped $800 into turning big sensorless RC controllers into soot. It was smart to choose a motor that is lower RPM to enable you to use the big Kellys. I wanted to keep my bike under 70lbs, so I used a pair of smaller high RPM motors, and it's been a PITA to make the electronics do more than turn to smoke. Fortunately, the motors use a slick active cooling setup that also serves as the mount, and they don't seem to get beyond luke-warm. That also might be because the controllers always shoot fire in a few minutes, so the motors never get time to heat up :)

I will contact you as soon as my body is ready, and I have a time that fits my work schedule. I'm excited to try it out!

Best Wishes,
-Luke
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Re: PMW Shocker

Postby northernmike » Mon Apr 13, 2009 4:33 pm

Now, we're getting somewhere! :mrgreen:
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Re: PMW Shocker

Postby huskydave » Tue Apr 14, 2009 12:09 pm

It appears that the preload and rebound dampening are adjusted by four bolts that tighten the elasomer cords and that is how it is either sped up of slowed down.
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Re: PMW Shocker

Postby dragonfire » Tue Apr 14, 2009 1:49 pm

Hi folks of Endless spheres,

greetings fromover the gopednation.com forum ( the board for us fanboys of the manufacturer of also this vehicle). I was reading over threads in here but never felt like registering, but anyways.... i felt like putting my 2 cants in here as about the cidli, it was largely discussed on the mentioned board allready and i tried it on myself of course.

C.i.d..l..i was tested on the Goped GTR "Trailripper" Standup scooter platform and withstood hard abuse by heavyweight riders, maintenance of the cushioning is only needed by those hardcore riders and is easily done by anybody on himself.

no hydraulic liquids to get speeled and pullute the environment, no heavy hydros to carry at the wheel/ cushioning but still having all this dampening feels great on a standup scooter application.

I on myself ( 130 lbs ) preferred the cidli suspension even as it use a "doorstopper" 8 it´s more than that), just cause the dive-effect is totally gone and i still hace all the cushioning needed to float over curbs and all obstacles a forestway/ trail can dish up - it´s like "Nike Air" for sporting shoes or hydropneumatic for a luxury sedan, but simpler and also adjustable according riders weight and preferences, the real cloudlike "softness" by the dynamic tensioning curve when jumping stairs, no hard hit amd hasty backweightening of the forks and totally no issues with the brake disk clearance on the rear like on my fully cushioned mtb are seemingly a great sulution for devices in this leightweight range.

Oh, and the design of a swingarm like the cidli ( but a different cushioning) is also utilitez in bike form, the collapsibe Go-biike ( not affiliated9 from canada also has this up for sale in actual times.
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Re: PMW Shocker

Postby PatmontS » Mon Apr 20, 2009 12:37 pm

PaulM wrote:Those are pretty impressive claims.

When do you start licensing this superior design to all the other manufacturers?


Thanks PaulM,
And thanks for asking that question (I hope you weren't being facetious!)
We're now seeking resources to help put the Shocker Tri-Sport electric motorcycle into production.
The USPTO has issued us patents on this amazing suspension system and we've just filed a new patent for several claims specific to motorcycle application.
Traditionally we've always created our IP to protect only what we produce, so we have no experience yet at licensing.
To help us get the Shocker into production, we would love to license our suspension technology to one or more of the great global motorcycle manufacturing brands.
If anyone has interest, experience and/or knowledge how we should best go about that, please email me at patmonts@goped.com

Thanks guys for the great discussion.
Sincerely,
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Re: PMW Shocker

Postby fechter » Mon Apr 20, 2009 2:11 pm

The suspension is cool and all that, but I want to know more about the motor, controller and battery system :wink: What good is a killer suspension if you don't have power? After all, that's mostly what we experiment with here.

BTW: I'm starting to pick up some experience with licensing agreements. Both with my medical device inventions (4 patents) and with my BMS circuits. It's all negotiable, and all over the map. Now... if I could only make money off one of them :(
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Re: PMW Shocker

Postby PatmontS » Mon Apr 20, 2009 2:42 pm

Fecter,
Was the reply seven posts previous not sufficient?
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Re: PMW Shocker

Postby huskydave » Mon Apr 20, 2009 10:04 pm

When can we see a video of this bike in action?
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