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Steering position

Brad Burnett

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I have a sw20 mr2 electronic power steering pump powered via a 100a crydom SSR, steering rack pressure sensor, and a string linear potentiometer on the column for steering position.

Im trying to greatly over complicate things and would like to configure a closed loop steering set up with multiple tables for on the fly switching via 2 DIs on a rocker switch.  

Have been through the software a few times and currently just the steering configured via a 3d table with driven speed(g4+ would have been non driven) on one axis and engine rpm on the other.

First hurdle that im finding is that the parameter "steering position" and "steering position ROC" are stated to only be able to come in via CAN in G4X.

These parameters are quite vital to the control strategy that im envisioning.  Im sure i could work around this with a GP ANV and a math channel but it just seems silly to have to do so.  

Any ideas on this overly complicated adventure would be super.


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Steering Pos ROC is not an ecu calculated channel, on modern cars that have steering position sensors, the ROC is calculated directly by the sensor on the column and sent over CAN.  

I dont see why you think it is silly to use a GP Analog, this is exactly what they are designed for.  The math for ROC is fairly easy.  Example below would give you Deg/sec updated every 0.01s (100Hz).


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@Adamw when i say silly, I'm more referring to the fact that the parameter is there but its bound only to CAN.  

With it set up as a GP Input and a math channel, can these values be viewed utilizing the "vehicle plan" data view?

And is there any way to utilize this with closed loop control for a target rack pressure based on vehicle speed and steering ROC?

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Yeah there is nothing much you can do about the steering ROC when the variable is designed to be calculated a separate device.  The steering position parameter I can put it on the list to look at, it could potentially be assignable but the general idea has been trying to keep the rarely used functions covered by generic functions where possible.  Neither of my suggestions would work in the vehicle plan view.


10 hours ago, Brad Burnett said:

And is there any way to utilize this with closed loop control for a target rack pressure based on vehicle speed and steering ROC?

Ive never really studied it but I always assumed pressure was static (controlled by the relief valve) and the pump speed control just varies the flow rate.  

There is no generic user configurable PID control loops at present but I believe there are plans to cover this type of functionality some how in the future.

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