NAME

ilowpass - Low-pass filter with integer inputs and outputs

SYNOPSIS

loadrt ilowpass [count= N|names=name1[,name2...]]

DESCRIPTION

While it may find other applications, this component was written to create smoother motion while jogging with an MPG.
 
In a machine with high acceleration, a short jog can behave almost like a step function. By putting the ilowpass component between the MPG encoder counts output and the axis jog-counts input, this can be smoothed.
 
Choose scale conservatively so that during a single session there will never be more than about 2e9/ scale pulses seen on the MPG. Choose gain according to the smoothing level desired. Divide the axis. N.jog-scale values by scale.

FUNCTIONS

ilowpass.N (requires a floating-point thread)
Update the output based on the input and parameters.

PINS

ilowpass.N.in s32 in
 
ilowpass.N.out s32 out
out tracks in*scale through a low-pass filter of gain per period.

PARAMETERS

ilowpass.N.scale float rw (default: 1024)
A scale factor applied to the output value of the low-pass filter.
ilowpass.N.gain float rw (default: .5)
Together with the period, sets the rate at which the output changes. Useful range is between 0 and 1, with higher values causing the input value to be tracked more quickly. For instance, a setting of 0.9 causes the output value to go 90% of the way towards the input value in each period.

AUTHOR

Jeff Epler

LICENSE

GPL