Good day,
The challenge of the day is to provide a calibration for an accelerometer output, expressed as a binary value.
I have an accelerometer whose operating range can be set (±2g, ±4g, ±8g). The accelerometer itself then generates a binary value at 16bit resolution. Hence, that 2^16 value (0-65535) represents an acceleration whose value depends on the ranges we set.
So, we make the asumption that the response is linear, allowing us to claim:
Acceleration = Scale x Binary Value + Offset
I have three axes worth of data, accelerometer A, B and C. If I hold the accelerometer stationary, the only thing I should be reading is the accleration due to gravity, g. This gets me the relationship
(A)^2 + (B)^2 + (C)^2 = g^2
since, in any orientation, the magnitude of the combination of all three acceleration readings should be the acceleration due to gravity (and that shouldn't change no matter which way you happen to be pointing the accelerometer).
What this gives me, then, is a nonlinear relationship of 6 variables (three scale factors and three offsets). I should be able to take six measurements in arbitrary orientations, which will give me six output values of each acclerometer. I should then be able to pull out the scale factors and offsets for each accelerometer, either in terms of g or relating to what I think g is.
My question, then, is how can I get Labview to do this? I'm see that there's a Solve Linear Equations tool, but I'm not seeing one appropriate for the nonlinear case. I'm also quite comfortable believing I'm just missing it :-)
Thanks!