AP_InertialSensor: calculate number of notches based on motor count

configure default harmonics if dynamic harmonics
set number of notches correctly for FFT operation
include static notch in filter calculation and allow harmonic options on static notch

libraries/AP_InertialSensor/AP_InertialSensor.cpp

@@ -5,12 +5,16 @@
 #if HAL_INS_ENABLED
 #include <AP_HAL/I2CDevice.h>
 #include <AP_HAL/SPIDevice.h>
+#include <AP_HAL/DSP.h>
 #include <AP_Math/AP_Math.h>
 #include <AP_Notify/AP_Notify.h>
 #include <AP_Vehicle/AP_Vehicle.h>
 #include <AP_BoardConfig/AP_BoardConfig.h>
 #include <AP_AHRS/AP_AHRS.h>
 #include <AP_ExternalAHRS/AP_ExternalAHRS.h>
+#if !APM_BUILD_TYPE(APM_BUILD_Rover)
+#include <AP_Motors/AP_Motors_Class.h>
+#endif
 
 #include "AP_InertialSensor.h"
 #include "AP_InertialSensor_BMI160.h"
@@ -529,8 +533,8 @@ const AP_Param::GroupInfo AP_InertialSensor::var_info[] = {
     AP_GROUPINFO("FAST_SAMPLE",  36, AP_InertialSensor, _fast_sampling_mask,   HAL_DEFAULT_INS_FAST_SAMPLE),
 
     // @Group: NOTCH_
-    // @Path: ../Filter/NotchFilter.cpp
+    // @Path: ../Filter/HarmonicNotchFilter.cpp
-    AP_SUBGROUPINFO(_notch_filter, "NOTCH_",  37, AP_InertialSensor, NotchFilterParams),
+    AP_SUBGROUPINFO(_notch_filter, "NOTCH_",  37, AP_InertialSensor, HarmonicNotchFilterParams),
 
     // @Group: LOG_
     // @Path: ../AP_InertialSensor/BatchSampler.cpp
@@ -869,12 +873,67 @@ AP_InertialSensor::init(uint16_t loop_rate)
     // configured value
     _calculated_harmonic_notch_freq_hz[0] = _harmonic_notch_filter.center_freq_hz();
     _num_calculated_harmonic_notch_frequencies = 1;
+    _num_dynamic_harmonic_notches = 1;
+
+    uint8_t num_filters = 0;
+    const bool double_notch = _harmonic_notch_filter.hasOption(HarmonicNotchFilterParams::Options::DoubleNotch);
+#if APM_BUILD_COPTER_OR_HELI || APM_BUILD_TYPE(APM_BUILD_ArduPlane)
+    if (_harmonic_notch_filter.hasOption(HarmonicNotchFilterParams::Options::DynamicHarmonic)) {
+#if HAL_WITH_DSP
+        if (get_gyro_harmonic_notch_tracking_mode() == HarmonicNotchDynamicMode::UpdateGyroFFT) {
+            _num_dynamic_harmonic_notches = AP_HAL::DSP::MAX_TRACKED_PEAKS; // only 3 peaks supported currently
+        } else
+#endif
+        {
+            AP_Motors *motors = AP::motors();
+            _num_dynamic_harmonic_notches = __builtin_popcount(motors->get_motor_mask());
+        }
+        // avoid harmonics unless actually configured by the user
+        _harmonic_notch_filter.set_default_harmonics(1);
+    }
+#endif
+    // count number of used sensors
+    uint8_t sensors_used = 0;
+    for (uint8_t i = 0; i < INS_MAX_INSTANCES; i++) {
+        sensors_used += _use[i];
+    }
 
+    // calculate number of notches we might want to use for harmonic notch
+    if (_harmonic_notch_filter.enabled()) {
+        num_filters = __builtin_popcount( _harmonic_notch_filter.harmonics())
+            * _num_dynamic_harmonic_notches * (double_notch ? 2 : 1)
+            * sensors_used;
+    }
+    // add filters used by static notch
+    if (_notch_filter.enabled()) {
+        _notch_filter.set_default_harmonics(1);
+        num_filters +=  __builtin_popcount(_notch_filter.harmonics())
+            * (_notch_filter.hasOption(HarmonicNotchFilterParams::Options::DoubleNotch) ? 2 : 1)
+            * sensors_used;
+    }
+
+    if (num_filters > HAL_HNF_MAX_FILTERS) {
+        AP_BoardConfig::config_error("Too many notches: %u > %u", num_filters, HAL_HNF_MAX_FILTERS);
+    }
+
+    // allocate notches
     for (uint8_t i=0; i<get_gyro_count(); i++) {
-        _gyro_harmonic_notch_filter[i].allocate_filters(_harmonic_notch_filter.harmonics(), _harmonic_notch_filter.hasOption(HarmonicNotchFilterParams::Options::DoubleNotch));
+        // only allocate notches for IMUs in use
-        // initialise default settings, these will be subsequently changed in AP_InertialSensor_Backend::update_gyro()
+        if (_use[i]) {
-        _gyro_harmonic_notch_filter[i].init(_gyro_raw_sample_rates[i], _calculated_harmonic_notch_freq_hz[0],
+            if (_harmonic_notch_filter.enabled()) {
-             _harmonic_notch_filter.bandwidth_hz(), _harmonic_notch_filter.attenuation_dB());
+                _gyro_harmonic_notch_filter[i].allocate_filters(_num_dynamic_harmonic_notches,
+                    _harmonic_notch_filter.harmonics(), double_notch);
+                // initialise default settings, these will be subsequently changed in AP_InertialSensor_Backend::update_gyro()
+                _gyro_harmonic_notch_filter[i].init(_gyro_raw_sample_rates[i], _calculated_harmonic_notch_freq_hz[0],
+                    _harmonic_notch_filter.bandwidth_hz(), _harmonic_notch_filter.attenuation_dB());
+            }
+            if (_notch_filter.enabled()) {
+                _gyro_notch_filter[i].allocate_filters(1, _notch_filter.harmonics(),
+                    _notch_filter.hasOption(HarmonicNotchFilterParams::Options::DoubleNotch));
+                _gyro_notch_filter[i].init(_gyro_raw_sample_rates[i], _notch_filter.center_freq_hz(),
+                    _notch_filter.bandwidth_hz(), _notch_filter.attenuation_dB());
+            }
+        }
     }
 
 #if HAL_INS_TEMPERATURE_CAL_ENABLE
@@ -912,7 +971,7 @@ AP_InertialSensor::detect_backends(void)
 
     _backends_detected = true;
 
-#if defined(HAL_CHIBIOS_ARCH_CUBE)
+#if defined(HAL_CHIBIOS_ARCH_CUBE) && INS_MAX_INSTANCES > 2
     // special case for Cubes, where the IMUs on the isolated
     // board could fail on some boards. If the user has INS_USE=1,
     // INS_USE2=1 and INS_USE3=0 then force INS_USE3 to 1. This is

libraries/AP_InertialSensor/AP_InertialSensor.h

@@ -17,7 +17,7 @@
 #define INS_MAX_INSTANCES 3
 #endif
 #define INS_MAX_BACKENDS  2*INS_MAX_INSTANCES
-#define INS_MAX_NOTCHES 4
+#define INS_MAX_NOTCHES 12
 #ifndef INS_VIBRATION_CHECK_INSTANCES
   #if HAL_MEM_CLASS >= HAL_MEM_CLASS_300
     #define INS_VIBRATION_CHECK_INSTANCES INS_MAX_INSTANCES
@@ -44,7 +44,6 @@
 #include <AP_ExternalAHRS/AP_ExternalAHRS.h>
 #include <Filter/LowPassFilter2p.h>
 #include <Filter/LowPassFilter.h>
-#include <Filter/NotchFilter.h>
 #include <Filter/HarmonicNotchFilter.h>
 #include <AP_Math/polyfit.h>
 
@@ -251,6 +250,9 @@ public:
     // harmonic notch current center frequency
     float get_gyro_dynamic_notch_center_freq_hz(void) const { return _calculated_harmonic_notch_freq_hz[0]; }
 
+    // number of dynamic harmonic notches
+    uint8_t get_num_gyro_dynamic_notches(void) const { return _num_dynamic_harmonic_notches; }
+
     // set of harmonic notch current center frequencies
     const float* get_gyro_dynamic_notch_center_frequencies_hz(void) const { return _calculated_harmonic_notch_freq_hz; }
 
@@ -498,12 +500,14 @@ private:
     bool _new_gyro_data[INS_MAX_INSTANCES];
 
     // optional notch filter on gyro
-    NotchFilterParams _notch_filter;
+    HarmonicNotchFilterParams _notch_filter;
-    NotchFilterVector3f _gyro_notch_filter[INS_MAX_INSTANCES];
+    HarmonicNotchFilterVector3f _gyro_notch_filter[INS_MAX_INSTANCES];
 
     // optional harmonic notch filter on gyro
     HarmonicNotchFilterParams _harmonic_notch_filter;
     HarmonicNotchFilterVector3f _gyro_harmonic_notch_filter[INS_MAX_INSTANCES];
+    // number of independent notches in the filter
+    uint8_t _num_dynamic_harmonic_notches;
     // the current center frequency for the notch
     float _calculated_harmonic_notch_freq_hz[INS_MAX_NOTCHES];
     uint8_t _num_calculated_harmonic_notch_frequencies;