surging

[docthrock]

Since the beginning of time (well, since installation), I've noticed that when my cruise is engaged, I can feel the gas ever so slightly go on and off and on and off. It's irregular, and it seems that the controller is overcompensating for speed in a very minute manner.  Of late, whenever the cruise is engaged, the "surging" feel, and "letting off" feel seems to becoming more noticeable. When I turn off the cruise and use the gas pedal, my 2008 smart passion, with computer 2.0 upgrade, is smooth as glass.

Any ideas?

[admin]

First, I have to ask if you got it recently and when you bought it did you ask for version 2 (which is in beta)?  If yes, then others beta testers have mentioned this as well.  I know you aren't part of the beta testing group, but Steven has provided V2 to customers that specifically ask for it.

If not... then these are my thoughts:

• You're extremely sensitive to it. Of some 6 or 7 hundred units sold and installed, the vast majority of customers have reported how smooth it is compared to other cruise controls.
• When you consider how a cruise control works, it is impossible for it to actually maintain a steady speed.  Its just math and physics.  It, by the nature of how flow process works, must constantly correct for error. As soon as there is no error (ie. you are at the desired speed exactly) then it has to wait until there is an error and then correct again.  The error and corrections are so small that normally you shouldn't be able to perceive it.
• Theoretically, it would become more noticeable as you approach something resembling "the perfect road" - that is, a frictionless perfectly smooth journey.  If you happen to live in a particularly flat area, it very well would be more noticeable than if you live in a hilly area (even slightly so).
• You say you feel it is becoming more noticeable.  I would suspect that is you noticing it more rather than it getting more noticeable.  There's nothing to wear out or degrade so there's really no way for it to get "worse".  Sure, the electronics could burn out but then it just wouldn't work at all.  Actually, I suppose the car could be wearing out.  Again theoretically speaking - as your tires wear or your transmission or other drive train components wears, the speed signals getting to the computer or perhaps the car's ability to react to the cruise outputs gets dulled and, over time, the very tiny corrections the cruise is making isn't enough to get the job done so it has to make bigger ones.  I'm just guessing.

I don't know if you've been following the V2 beta testing threads, so you may or may not know that we are waiting on some programmers to be delivered.  Once we have those, customers can buy them and update their cruise controls whenever and they wish with various firmware versions that we can try.  Right now we have only V1 and V2 but part of the reason for slow deliberate development is because we don't want people sending units back and forth for "half baked" firmware changes.  But if customers have the ability to program their units themselves, then we can release minor firmware changes and get more rapid feedback from customers.
 
By "program" I don't mean you need to know how to change the firmware.  I mean we make the changes (based on feedback) and post the firmware to the website which customers can download and put onto their cruise control via the (hopefully) soon-to-be-available programmer devices.
 
Because your complaints is extremely unlikely to be a problem with your unit, I'm moving this out of the warranty section and into product feedback.
 
Art

[John_H]

As another satisfied Area451 customer, I'll suggest a quick check.

Find another Area451 owner near you and see if you can do a quick, temporary swap of the Area451 controller boxes to see if the surging follows the unit or follows the car.  Since I'm in Florida rather than Indiana at the moment, I can't volunteer my services too conveniently.

-- The following brainstorming might be a little inappropriate for the forum but I'm an engineer who likes to see the possibilities in a situation explored. --

Since I don't know everything on the interface I can't be certain but it seems unlikely that any loose pins with the installation would result in the ability to work yet not provide a smooth ride.  Any assembly problems within the Area451 that can occur "in the field" in any electronic products (such as a marginal solder joint on a data line) should also result in a full failure rather than the subtle surge in a digital control system.

It's possible your smart has subtleties that makes fine control of the unit difficult and that those surges would occur under your own control of the gas pedal but you notice it less when you're actively controlling the engine yourself.

I have experienced surging in my previous car - a BMW roadster - going down hills where a very light accelerator is appropriate.  Is the surging you experience typically in a certain situation?

I find the Area451 to be an all-around better control loop than the previous cruise controls I've used because of observations like that other car's surging.

[admin]

As another satisfied Area451 customer, I'll suggest a quick check.

Find another Area451 owner near you and see if you can do a quick, temporary swap of the Area451 controller boxes to see if the surging follows the unit or follows the car.

Swapping the units is not a bad suggestion, just to be sure.  In fact, perhaps I took this out of the warranty section too hastily.  Docthrock... if you feel something may be wrong or degrading with your unit, we can swap it out for you if you'd like - under warranty - just in case.  I really don't think it will help, but we've had so few warranty issues that I think the responsible thing to do would be to make sure.

I have experienced surging in my previous car - a BMW roadster - going down hills where a very light accelerator is appropriate.

In theory in a perfect world (such as our homeworld), the point of most trouble would be an exact level surface.  However, with gravity and rolling resistances in practice it would make sense that some small to moderate degree of decline would be the real world equivelent of "exact level".

[wizard of ahs]

Docthrock & Art,

I would be willing to swap units with Doc !!!  We are close and he would be able to see if it's his UNIT or his CAR !!

Also, I would be able to match it against mine !!!

Two opinions might be better than one 

Just throwing it out there 

[admin]

That's a good idea and up to you guys.

I'll reiterate that I don't think it will matter.  Whether the cruise is on or off, it is always processing the signals (either calculating new ones or reading the pedal's original signals and spitting out identical ones) so the fact that docthrock says it feels perfect with the cruise off indicates to me that the unit is working as intended.

Art

[docthrock]

Thanks for moving my post to the appropriate area. I wasn't expecting any warranty consideration, I was just wondering if my unit had a problem and perhaps was "fading" toward malfunction. Or perhaps I have a broken or loose pin or something?

Mike, soon as the snow clears, I'll PM you from the other board and we'll see about swapping units. Or I'll just let you drive my car and see what you think. I'm still out your way about every day.

Perhaps I am getting more sensitive to the controller surging and letting off. Originally thought it might be wind. And perhaps I notice it under nearly perfect road conditions. I activate the cruise about every day on my 9 mile commute on a 4 lane US highway, no traffic, no radio, about 60 mph.

I actually mentioned the issue a long time ago on the SCA forum, wondering if anyone else noticed it. No one seemed to have the same issue, the same sensation, if you will.

My cruise was one of the first ones sold. I think I got mine out of the second batch.

I've had MANY other cars, trucks and motorcycles with cruise control, some factory installed, a few that I've installed.  My smart cruise works just as well (if not better) than all the others, but sorry, I've not noticed any of the others having this continuous minute palpable feel. Don't get me wrong, the unit works very well, it just seems to me that I can constantly feel very slight adjustments, up and down.  I've never noticed what sort of feels like a "digital" response, all my other cruises seem to work like "analog".  Which means to say gradual, steady increase and decrease of power to compensate for terrain, conditions. My smart cruise seems to have a continuous minute amount of on, off, on, off....  And it's definitely not there when the cruise is disengaged.

Matt

[admin]

Thank you for more details Matt.  That sensation you're describing would not be there when the cruise is disengaged.  I only meant that the cruise is still fully active when it is disengaged so if it were electronically defective you'd (probably) have problems all the time.  I do believe you are experiencing... well, exactly as you describe... minute corrections for speed fluctuations.  The smart car has a digital pedal.  Most cars don't.  While the term "digital" enjoys a healthy reputation in this modern age, it is, in many ways, inferior to analog - just ask any HiFi stereo owner.  There's no "half way" in a digital world.  The smart pedal, for example, has (in theory) 255 positions (in reality its much less than that).  So if you want position 124 or 125 that's fine, but if you need 124.5 you're out of luck.  With an analog input there is an infinite number of sub-positions throughout the range.  Bu I can't blame it entirely on being digital.  You're possibly noticing a shortcoming in our algorithm for your particular situation and sensitivity.  We tested and tested and tested... and we thought we nailed it, and from the feedback of the overwhelming majority of customers it looked like we were right.  However its very difficult to get the perfect algorithm especially for all situations.  Most of our testing was done in the mountains, where subtle corrections aren't going to be noticed very easily (and where its very important to not have too-subtle corrections!).

Is your unit defective?  I still think not.  Could it be improved?  Most probably.  In fact, when Steven was doing the original field testing he kept complaining of a slight pulsing on flats and minute declines.  We tried several tweaks but invariably it would make something else worse (for example, it couldn't hold speed on a steep hill).  Eventually we collectively determined that the extra time and money going into refinement wasn't going to make enough of a difference plus we weren't really going to know until we started getting feedback in bulk (and of course, most people said it was good).  When we were working on V2 I personally thought I had improved it, but feedback from nearly all the participants suggested it was worse, not better.  Ironically, Steven also said it was improved.  The conclusion then is there is always going to be a significant variance in conditions and preferences among the user base such that it will be nearly impossible to make it ideal for everyone.  The old addage comes to mind:  you can make some of the people happy all of the time and you can make all of the people happy some of the time, but you can't make all of the people happy all of the time.

But with the upcoming programmers... perhaps we can get closer.  It will allow us to more easily "try" things.  We can hypothesize what might be an improvement for your situation; make the adjustments; upload the firmware and allow you to download it and test it and report.  All without having to have you send the unit to us and wait for it to return.  I still can't promise we'll ever fix your issue but it allows us to try.

Thanks again for your invaluable feedback.

Art