205 corsa c epas column

[pug_ham 244 3 Cars]

Does anyone know anything about using the mgf epas as they give a bit more feel, apparently.

 

g

[Silvermetis 6]

I have been collecting parts for my Corsa EPAS conversion for sometime the only outstanding problem was the lower link. 

Reading ftoomsh's description of removing the UJ and fitting the peugeot connector I was fired with enthusiasm. In reality it was much harder to do than just remove the indents and tap the caps out. In the end I sacrificed one UJ and one yoke knocked the UJ caps through the yokes and reassembled the joint.

 

I built the conversion as a kit of parts to make it easy to make another one if needed it was surprising how many parts need little conversion, it a pity vauxhall couldn't have been a bit more considerate when they postioned the motor mounting flange and rotated the fixing bolts, it would not have been necessary to move the ECU.

 

Below are the photos of the kit and final assembly.

[Silvermetis 6]

I have finally completed the design of my control unit for the corsa ePAS.

 

The unit is completely automatic needs no knob twiddling, signal shapers or speedo correctors.

 

It will accept any speed related input and allows you to select your own transition points between high, medium and low assistance unlike the corsa preset 18mph and 45mph settings.

 

Have a look at the article I welcome your comment, if you have any questions just ask.

 

 

Article corsa controller.pdf

[petert 588]

That is a fantastic effort. I was going to just run the speedo sensor but I like the variable circuit.

[Silvermetis 6]

Pleased you liked article I presume you are using the speedo output from the 3 way speedo drive in which case circuit will be exactly the same as mine. if you use a different speedo input let me know and I will advise what resistors and capacitors need to be changed, I have still got the breadboard circuit so can test and confirms values for you.

[ftoomsh 5 1 Cars]

Great job Silvermetis. I didnt use a speed sensor just a variable potentiometer that I got off ebay. This allows me to adjust the assistance as I go along.. but mine is in a rallycar.

[Silvermetis 6]

Thanks,

 

If I was using it in a rallycar I think I'd just use the stepped oscillator with a column mounted switch to switch assistance levels, you could have a switch on the handbrake to switch into max assistance when handbrake is applied, you only need 7 components and two switches.

 

Potentiometers are unreliable and need constant adjustment when you are best focusing on driving.

[petert 588]

You mention in your article that the std sensor only runs at approx. 1/3 the frequency required and thus won't switch out of High assistance until 60mph. I presume that is with the standard 205 speedo gears? I have a good collection here. What if I mixed and matched gears to get a higher frequency? I guess I really need >320Hz which isn't going to happen with just gearing alone.

[Silvermetis 6]

You have answered your own question the change in gearing you can get by changing gears is minimal and is used for speedo correction for different size tyres or final drive ratios.

 

It was this that motivated me to develop my controller. My aim was to make the Corsa ePAS work exactly the same in a 205gti as it did in the donor car.

 

Since my post it is apparent that some people with rallycars would prefer a semi automatic system that can be switched manually with an automatic switch to maximum assistance when the handbrake is applied. This would be easy to make as I have already done most of the work with the stepped oscillator. I was thinking in terms of a column mounted stalk switch , like those used for head and side light, so you could just flick the switch between assistance levels rather than twiddle a potentiometer knob.

 

What is your requirement road or rally?

 

 

[Spesh 31 1 Cars]

I'd be interested in a built unit if you ever produce them.  I could possibly build it myself but I prefer to stick what I know i'm ok at and leave other stuff to people more skilled than I   Good job though

[petert 588]

15 hours ago, Silvermetis said:

What is your requirement road or rally?

Circuit racing. I do like the idea of being able to vary assistance initially. Once set though, I probably wouldn't change it. Couldn't I do the same with an Arduino and do variable frequency multiplication?

 

Edited March 13, 2021 by petert

[Silvermetis 6]

Hi Pitcrew,

 

Arduino is outside my pay grade., if it wasn't I would have remapped the standard corsa.

 

I learnt my electronics 50 years ago and most of components I use have been available as long.

 

My advice would be keep it simple, a stepped oscillator with column switch would be ideal for track use and allow you to switch assistance levels irrespective of speed.

[Silvermetis 6]

Hi Spesh,

 

I am not really into manufacturing but I know a company in Yorkshire that sells PAS conversion kits he uses one of the ebay potentiometer controllers. i will give him a call tomorrow and see if he is interested in building them.

 

If that fails I have a software design package that can create double sided board layouts from circuit diagrams, I had intended to use it to produce my circuit diagram but it  is not easy to use and my lack of experience using it was making me lose the will to live.

 

If we could get boards made cheaply putting all the components on is fairly easy.

[wicked 103 3 Cars]

Nice effort on the controller design! 

 

If you want to go Arduino, have a look at these: https://www.adafruit.com/product/1501

No need to do custom boards; only thing you might need to do is beef up the output from 5V to 12V if the corsa controller needs that.

It has already 12V (upto 16V) battery input. All you need to do is attach your speedsensor to 5V LDO iso 12v and let it measure your speed, determine your needed level of assistance and set an output pwm to zone A, B or C frequency.

Mind that you need to make the measurement with internal hardware timer and not SW based, otherwise you get jitter due varying execution speed of the SW. (used them before on these kind of applications)  

[Silvermetis 6]

Hi Wicked,

 

I hadn't considered Arduino as I have little experience of the product but you have open my eyes. I would certainly consider it in the future it seems easy enough to program. 

 

For this particular application I would still have gone for my solution as I think an Arduino based solution would require too many external component as it is likely the output signal would need reshaping and engine start detect would still be required.

 

For my development I use a signal generator with a serial port (3 euros from China) which could interface with Arduino processor for future projects 

[wicked 103 3 Cars]

With the mentioned adafruit thingy, you don't need much external components. Used one as interface between speed sensor and ECU; you can use the speed sensor on the 5V supply, hook the battery input to your switched 12V and off you go. Only thing you might need is to have a level shifter from 5V output to 12V if the Corsa controller cannot deal with 5V signaling. The PWM stuff can be done with processor. 

But if you're more confident with analog stuff (not my cup of tea), then your solution is likely the better one.