PID tuning: one vs multiple loops, gain scheduling

component whitenoise "Generate white noise";
pin in float amplitude=1.0 "Amplitude of the white noise";
pin out float out "white noise output";
function _;
description """
White noise generator, can be used to find mechanical system resonances
""";
license "GPL"; // indicates GPL v2 or later
author "DaBit (dabitATicecoldcomputingDOTcom)";
;;

#include <rtapi_math.h>

// ran2 random number generator from 'numerical recipes in C'

#define IM1 2147483563
#define IM2 2147483399
#define AM (1.0/IM1)
#define IMM1 (IM1-1)
#define IA1 40014
#define IA2 40692
#define IQ1 53668
#define IQ2 52774
#define IR1 12211
#define IR2 3791
#define NTAB 32
#define NDIV (1+IMM1/NTAB)
#define EPS 1.e-14
#define RNMX (1.0-EPS)

static int randx=0;

double ran2(int *idum)
{
    int j;
    int k;
    static int idum2 = 123456789;
    static int iy = 0;
    static int iv[NTAB];
    double temp;

    if (*idum <= 0) {		// *idum < 0 ==> initialize
	if (-(*idum) < 1)
	    *idum = 1;
	else
	    *idum = -(*idum);
	idum2 = (*idum);

	for (j = NTAB+7; j >= 0; j--) {
	    k = (*idum)/IQ1;
	    *idum = IA1*(*idum-k*IQ1) - k*IR1;
	    if (*idum < 0) *idum += IM1;
	    if (j < NTAB) iv[j] = *idum;
	}
	iy = iv[0];
    }
    k = (*idum)/IQ1;
    *idum = IA1*(*idum-k*IQ1) - k*IR1;
    if (*idum < 0) *idum += IM1;

    k = idum2/IQ2;
    idum2 = IA2*(idum2-k*IQ2)-k*IR2;
    if (idum2 < 0) idum2 += IM2;

    j = iy/NDIV;
    iy = iv[j] - idum2;
    iv[j] = *idum;
    if (iy < 1) iy += IMM1;

    if ((temp = AM*iy) > RNMX)
	return RNMX;
    else
	return temp;
}

double randinter(double a, double b)	/* return a random number uniformly
					   distributed between a and b */
{
    return a + (b-a)*(ran2(&randx));
}



FUNCTION(_)
{
	out = randinter(amplitude*-1.0, amplitude);
}

component sinesweep "Generate a linear sine sweep";
pin in float amplitude=1.0 "Amplitude of the output sine";
pin out float output "sine sweep output";
pin out float current_frequency "Current frequency";
pin io bit start "Set to 1 to start the sweep. The component will reset this pin to 0 when done";
param rw float start_freq "Start frequency";
param rw float end_freq "End frequency";
param rw float sweep_duration "Duration of the sweep in seconds";
param r float dbg_fperiod;
variable float angle;
variable float curr_freq;
variable int prev_start=0;
variable int busy=0;
function _;
description """
Linear sine sweep generator, can be used to find mechanical system resonances.
""";
license "GPL"; // indicates GPL v2 or later
author "DaBit (dabitATicecoldcomputingDOTcom)";
;;

#include <rtapi_math.h>

#define PI2 6.283185307179586476925286766559

FUNCTION(_)
{
	if (prev_start == 0 && start) {
		start = 1;
		prev_start = 1;
		busy=1;
		angle = 0.0;
		curr_freq = start_freq;
	} else {
		if (!busy) {
			prev_start=0;
			output = 0.0;
			current_frequency = 0.0;
		}
	}
	if (busy) {
		curr_freq += (((end_freq-start_freq)/sweep_duration)*fperiod);
		current_frequency = curr_freq;
		if (curr_freq > end_freq) {
			busy=0;
			start=0;
			prev_start=0;
		} else {
			angle += PI2*curr_freq*fperiod;
			output = (amplitude*sin(angle));
		}
	}
	dbg_fperiod = fperiod;
}