Map63Vette
Well-Known Member
Yeah, I would think as long as you could digitize a tach and vss signal somehow that you could make it work. The Megasquirt just made it more convenient for me because I already had the tach and VSS available, I just had to convert the message format to what the steering controller wanted to see. If you could get the values directly into an Arduino via some other circuitry then I don't see why you couldn't get the same results.
I'm tossing around a few ideas on the assist level, but it mostly just comes down to whether I wanted it adjustable on the fly or just hard coded in to something I like. Right now I just pass the speed value from the MS through the Arduino to the EPS controller at a 1:1 ratio, so whatever speed the MS sends the Arduino, it sends the same speed to the EPS controller. To try to lighten up the assist I would do some math on the speed in the Arduino before it sends it back out. There's a couple different ways I could do that as well.
One way would be to just multiply the speed so that I still have near full assist at low/no speed like parking lots, but the assist ramps down quicker as the speed builds. So for example, if I assume the EPS has minimum assist by 70 mph, if I multiple my current speed by 2 it would mean that I would have minimum assist by 35 mph. So the steering would get a lot heavier a lot faster. Another option would be to just offset the speed by some number, like say 20 mph. That would make it harder to steer at a standstill since the car now thinks it's going 20 all the time, even when it's not moving, but it would mean I'd have minimum assist by 50 mph. Or, I could just send it a fixed value all the time and not let it be variable at all. So I could just send it 70 mph all the time and see what it feels like.
For all of those, I could either just hard code the math in and do some guess and check, or I've thought about putting in a button or knob that I could use to change them on the fly. So in position one maybe my speed multiplier is 1, at position 2 it's 1.2, position 3 1.5, position 4 2, etc. Same idea with the offset or fixed values as well. Each position of the switch could be a different value. I could do it with a button as well and just have every press cycle through to the next value and then loop back around (or have separate up and down buttons). It would kind of be like modern cars with comfort and sport modes.
Just sending it a fixed value is probably a good place to start though as that would let me test it and see how the steering feels at all the different speeds. Since the MS is actually reading the torque sensor messages I could datalog them as well and see if I can make any sense of them and possibly even try to graph the response.
I'm tossing around a few ideas on the assist level, but it mostly just comes down to whether I wanted it adjustable on the fly or just hard coded in to something I like. Right now I just pass the speed value from the MS through the Arduino to the EPS controller at a 1:1 ratio, so whatever speed the MS sends the Arduino, it sends the same speed to the EPS controller. To try to lighten up the assist I would do some math on the speed in the Arduino before it sends it back out. There's a couple different ways I could do that as well.
One way would be to just multiply the speed so that I still have near full assist at low/no speed like parking lots, but the assist ramps down quicker as the speed builds. So for example, if I assume the EPS has minimum assist by 70 mph, if I multiple my current speed by 2 it would mean that I would have minimum assist by 35 mph. So the steering would get a lot heavier a lot faster. Another option would be to just offset the speed by some number, like say 20 mph. That would make it harder to steer at a standstill since the car now thinks it's going 20 all the time, even when it's not moving, but it would mean I'd have minimum assist by 50 mph. Or, I could just send it a fixed value all the time and not let it be variable at all. So I could just send it 70 mph all the time and see what it feels like.
For all of those, I could either just hard code the math in and do some guess and check, or I've thought about putting in a button or knob that I could use to change them on the fly. So in position one maybe my speed multiplier is 1, at position 2 it's 1.2, position 3 1.5, position 4 2, etc. Same idea with the offset or fixed values as well. Each position of the switch could be a different value. I could do it with a button as well and just have every press cycle through to the next value and then loop back around (or have separate up and down buttons). It would kind of be like modern cars with comfort and sport modes.
Just sending it a fixed value is probably a good place to start though as that would let me test it and see how the steering feels at all the different speeds. Since the MS is actually reading the torque sensor messages I could datalog them as well and see if I can make any sense of them and possibly even try to graph the response.
