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Filter: allow harmonics and notch-per-motor in harmonic notch

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allow default harmonics to be configured
allow combination of harmonics and indpendent centre frequencies
pre-calculate number of harmonics
This commit is contained in:
Andy Piper 2021-11-13 22:39:35 +00:00 committed by Andrew Tridgell
parent 4e405244b9
commit 34920ebd60
2 changed files with 23 additions and 18 deletions
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32
libraries/Filter/HarmonicNotchFilter.cpp
View File

@ -16,7 +16,7 @@
#include "HarmonicNotchFilter.h"
#include <GCS_MAVLink/GCS.h>
#define HNF_MAX_FILTERS 6 // must be even for double-notch filters
#define HNF_MAX_FILTERS HAL_HNF_MAX_FILTERS // must be even for double-notch filters
#define HNF_MAX_HARMONICS 8
// table of user settable parameters
@ -136,27 +136,20 @@ void HarmonicNotchFilter<T>::init(float sample_freq_hz, float center_freq_hz, fl
allocate a collection of, at most HNF_MAX_FILTERS, notch filters to be managed by this harmonic notch filter
*/
template <class T>
void HarmonicNotchFilter<T>::allocate_filters(uint8_t harmonics, bool double_notch)
void HarmonicNotchFilter<T>::allocate_filters(uint8_t num_notches, uint8_t harmonics, bool double_notch)
{
_double_notch = double_notch;
_num_harmonics = __builtin_popcount(harmonics);
_num_filters = _num_harmonics * num_notches * (double_notch ? 2 : 1);
_harmonics = harmonics;
for (uint8_t i = 0; i < HNF_MAX_HARMONICS && _num_filters < HNF_MAX_FILTERS; i++) {
if ((1U<<i) & harmonics) {
_num_filters++;
if (_double_notch) {
_num_filters++;
}
}
}
if (_num_filters > 0) {
_filters = new NotchFilter<T>[_num_filters];
if (_filters == nullptr) {
GCS_SEND_TEXT(MAV_SEVERITY_WARNING, "Failed to allocate %u bytes for HarmonicNotchFilter", (unsigned int)(_num_filters * sizeof(NotchFilter<T>)));
GCS_SEND_TEXT(MAV_SEVERITY_ERROR, "Failed to allocate %u bytes for notch filter", (unsigned int)(_num_filters * sizeof(NotchFilter<T>)));
_num_filters = 0;
}
}
_harmonics = harmonics;
}
/*
@ -216,9 +209,18 @@ void HarmonicNotchFilter<T>::update(uint8_t num_centers, const float center_freq
const float nyquist_limit = _sample_freq_hz * 0.48f;
_num_enabled_filters = 0;
// update all of the filters using the new center frequencies and existing A & Q
for (uint8_t i = 0; i < HNF_MAX_HARMONICS && i < num_centers && _num_enabled_filters < _num_filters; i++) {
const float notch_center = constrain_float(center_freq_hz[i], 1.0f, nyquist_limit);
for (uint8_t i = 0; i < num_centers * HNF_MAX_HARMONICS && _num_enabled_filters < _num_filters; i++) {
const uint8_t harmonic_n = i / num_centers;
const uint8_t center_n = i % num_centers;
// the filters are ordered by center and then harmonic so
// f1h1, f2h1, f3h1, f4h1, f1h2, f2h2, etc
if (!((1U<<harmonic_n) & _harmonics)) {
continue;
}
const float notch_center = constrain_float(center_freq_hz[center_n] * (harmonic_n+1), 1.0f, nyquist_limit);
if (!_double_notch) {
// only enable the filter if its center frequency is below the nyquist frequency
if (notch_center < nyquist_limit) {

9
libraries/Filter/HarmonicNotchFilter.h
View File

@ -20,7 +20,6 @@
#include "NotchFilter.h"
#define HNF_MAX_HARMONICS 8
#define HNF_MAX_HMNC_BITSET 0xF
/*
a filter that manages a set of notch filters targetted at a fundamental center frequency
@ -31,7 +30,7 @@ class HarmonicNotchFilter {
public:
~HarmonicNotchFilter();
// allocate a bank of notch filters for this harmonic notch filter
void allocate_filters(uint8_t harmonics, bool double_notch);
void allocate_filters(uint8_t num_notches, uint8_t harmonics, bool double_notch);
// initialize the underlying filters using the provided filter parameters
void init(float sample_freq_hz, float center_freq_hz, float bandwidth_hz, float attenuation_dB);
// update the underlying filters' center frequencies using center_freq_hz as the fundamental
@ -60,6 +59,8 @@ private:
bool _double_notch;
// number of allocated filters
uint8_t _num_filters;
// pre-calculated number of harmonics
uint8_t _num_harmonics;
// number of enabled filters
uint8_t _num_enabled_filters;
bool _initialised;
@ -89,7 +90,9 @@ public:
// set the fundamental center frequency of the harmonic notch
void set_center_freq_hz(float center_freq) { _center_freq_hz.set(center_freq); }
// harmonics enabled on the harmonic notch
uint8_t harmonics(void) const { return hasOption(Options::DynamicHarmonic) ? HNF_MAX_HMNC_BITSET : _harmonics; }
uint8_t harmonics(void) const { return _harmonics; }
// has the user set the harmonics value
void set_default_harmonics(uint8_t hmncs) { _harmonics.set_default(hmncs); }
// reference value of the harmonic notch
float reference(void) const { return _reference; }
// notch options