# Any intrest in Cruise Control for DIY EV



## jwiger (Oct 18, 2014)

I want cruise, I also want the option of adjustable on the fly speed limiter. Say you're in a 25mph neighborhood. I want the 0-80% range of the pedal to limit the car to less than or equal to 25. If o go greater than 81% it would override and go faster. There are a few other features I want too. I don't know how ambitious you are, but I'd be willing to share. 

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## goingbush (Jun 20, 2017)

jwiger said:


> I want cruise, I also want the option of adjustable on the fly speed limiter. Say you're in a 25mph neighborhood. I want the 0-80% range of the pedal to limit the car to less than or equal to 25. If o go greater than 81% it would override and go faster. There are a few other features I want too. I don't know how ambitious you are, but I'd be willing to share.
> 
> Sent from my STV100-1 using Tapatalk


That should not be too difficult , just add an extra button into the mix .


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## brian_ (Feb 7, 2017)

goingbush said:


> Reading through the forums I gather there does not seem to be a decent cruise control out there, other than the old ICE system with a vacuum servo or stepper that hooks up to the throttle pot via the old cable method.


Even IC engined cars don't do that any more! I would much rather go without cruise control than pile that stuff in an electric car, and I guess that's the point.

This should obviously be a feature of the controller. If controllers don't offer this, the manufacturers are either doing a lousy job, or they're not even trying to serve the road-going vehicle market... which is a possibility, as some of them (such as Curtis) are clearly targeting industrial and other non-road applications.

The add-on controller idea would work... it's just unfortunate if one has to add hardware for a feature that could be added with just software. In a Curtis, it might be possible to add cruise control in VCL code... for anyone set up to do that, which is not the average hobbyist.

A quick web search for EV cruise control led right back to this forum, to a seven-year-old thread:
Cruise Control
I've only read the first page, but the message there seemed to be

it's actually difficult to program (although it is a standard feature of every modern car and has been implemented in cheap add-on devices for decades ), and
cruise control is bad anyway (now that's rationalization ).

I noticed one interesting comment in that thread:


Tesseract said:


> ... cruise control was considered a luxury option on many vehicles until just a couple years ago, so your surprise that it isn't included in EV motor controllers is what struck me as a bit disingenuous. Sure it only requires adding lines of code to the software that, e.g., runs the Soliton1 to implement cruise control, but the code is already over 5500 lines long and that is quite an achievement for a single man (Qer) to accomplish in about 2 years while working full time at a "real job".


Three points come out of this:

cruise control was an extra-cost option because it required additional parts; since cars designed in this century have powertrain control computers (for emissions and economy) with speed sensing (for ABS) and have gone to "throttle by wire", the incremental cost is zero
seven years have gone by and cruise control is now an expectation of almost any car or truck
5500 lines of usefully functional and reliable code is an impressive body of work for one person, but does not seem large by modern standards of embedded control systems.


In the really hilarious category:
Electric Bicycle Brushless Motor Controller 48V/72V 1500W For E-bike & Scooter
This US$65 controller for an e-bike has (or had, it's an old ad) cruise control.


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## jenkinskg (Nov 4, 2017)

So I bought this, will add mag sensor onto one of the shaft to rear wheel
2013 smart EV

got this for $30 on ebay, new old stock,will update thread next week


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## CKidder (Dec 12, 2009)

I've had cruise control on a couple of EV projects for years now. It isn't that hard to add if you're already making a VCU to control your hardware. Since I'm the guy who wrote like 90% of GEVCU it wasn't too difficult to add cruise control to my project as I went. For the usual EV scheme where you've got a single speed gearbox cruise just turns into a PID loop on your torque with RPM as a reference signal. Yeah, tweaking the coeffs to make it work smoothly is a little bit of a pain and you do have to figure out what you want to do about regen if you have regen on the accelerator pedal. But, the proper place for cruise is either at your VCU or at the motor controller itself. Either of them know enough about the vehicle to easily implement cruise. It's really quite simple on either of them.


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## jwiger (Oct 18, 2014)

Kidder,
How about driving two different types of motors with one throttle pedal? Think a look-up chart could be used with a torque axis and an rpm axis to provide differential throttle outputs to the two different motors?

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## CKidder (Dec 12, 2009)

jwiger said:


> Kidder,
> How about driving two different types of motors with one throttle pedal? Think a look-up chart could be used with a torque axis and an rpm axis to provide differential throttle outputs to the two different motors?
> 
> Sent from my BlackBerry using Tapatalk. -Yeah, a BlackBerry.


Are you talking about two different electric motors or an electric and a gas motor? Two electric motors are no problem even if they're different power levels. You could mostly just split the torque command between them, An electric and a gas motor is a much more difficult problem. The two don't act even remotely close to the same. Maybe in that case your idea of a mapping table would work.


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## jwiger (Oct 18, 2014)

Kidder,
Going down a tangent, unfortunately. I will shoot you a PM later. 

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