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I was thinking more about the PID problems and I think my electro-hydraulic actuator design is flawed. A master cylinder's pressure isn't a function of the cylinder travel (it is when using a vac booster due to how the booster works), it is directly related to the force acting on it. Using the 100kg actuator it is pretty much zero-max in a fraction of a mm of travel. Deflection in the hose and caliper makes it very slightly linear though the curve is so steep the pid control won't be able to make sense of it.

I think if I insert a spring between the actuator and master, it'll translate travel to force more linearly. I'm not sure I have a spring that is rated to 100kgs though I do have a lot of valve springs about. I've no idea what a valve spring is designed to hold but it'll be worth a try!

Edit: Valve spring holding force, seated, open. Right on the money!
Stock Small Block 105 - 125 lbs. 220 - 280 lbs.

Much better!

Mower valve springs did the trick. Much better load control now. Linear from zero to stalling 5th gear WOT. Stalling under full power still has a CM or so travel before the spring has collapsed. I'd prefer a little more spring travel but I can shop around for springs once the wheel speed issue is solved.

I've got a VE commodore hub on its way. It has a 42 tooth tone wheel with integrated pickup sensor. I'll use a pulsar dizzy spark module to filter the vr output into a logic level for the arduino.

With 42 pulses per revolution and my code running in a 100mS loop we'll have fast updates for the pid routine as well as fine rpm resolution. Around 14rpm I think it worked out to.

Just need to wait for the hub...

Wow thats a good thought and excellent results

Excellent work!
Love the engineering on the fly.
Great solutions to those 'temporary road blocks'.

Thanks guys

so the VE hub arrived, and of course they increased the stud size from 12.7mm to 14mm... I'm a little hesitant redrilling the cnc'd flanges so back to the drawing board for now regarding wheel speed sensing. I'm considering pulling the VSS from the transaxle and using that for testing. I've read its 4 pulses per rotation pre-diff? so possibly around 12ppr.

I'll try rig something up when it defrosts out there

Wouldn’t a pre ve hub do the job? I have no idea on ppr though. Vr-vt s1 had the plug adapter that stayed in the knuckle, so it’s more convenient to use a vt s2-vz as the to pin plug is part of the hub. This makes connection a breeze.

It would though the rotor is 10mm smaller, smaller pad area, thinner rotor, less cooling, and less mass by about 1.2kgs. Plus I've just found out pre VE is variable reluctance where VE and on uses hall sensors for the speed sensor. Arguably easier to interface to.

I spose that depends on which rotor size you use. There’s three different sizes. Although the pre ve hub is 2mm larger on the hub centric. But if the pickup type is easier for the ve I guess another attack plan will come into play.
I’m not that smart these days, so I will leave it to you

VE seems like the way to go, the hub I have came from an Omega which I think is a base model? If larger hubs and callipers are available even better! browsing on ebay, there looks to be more VE stuff and cheaper than earlier models - though a lot more early model stuff locally on facebook and gumtree for cheaper. With the lockdowns eBay is the way to go

I'll pop it on the bench tonight and get the scope out to see what the 2 wire hall sensor is doing. From what I've read its a current loop sensor so it'll pass 12 or 24mA depending if there's a tooth near by or not. Not the most ideal but a lot easier to manage than VR.

I've redesigned my hub adaptor for the 66.9mm VE center and the 14mm studs. Getting any and all wobble out of the system is as important as a working hub load. I'll send the design away today and hope to have it here in a couple of weeks. They're only $80 a pop from PCBWay.

In the mean time, I've just soldered up an opamp to filter the VR signal and I've extended the pickup snout on my VR sensor to reach into the cooling fins of the current hub setup. I'll weld up a mount after lunch and hopefully get a positive result

I use the MAX9924 for my VR needs ...

-Enjoy