Merge branch 'lowpass' of https://github.com/fusterjj/cleanflight into fusterjj-lowpass
Conflicts: src/main/flight/mixer.c
This commit is contained in:
Dominic Clifton
commit
a1b01807cf
1
Makefile
1
Makefile
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|
@ -206,6 +206,7 @@ COMMON_SRC = build_config.c \
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flight/pid.c \
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flight/imu.c \
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flight/mixer.c \
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flight/lowpass.c \
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drivers/bus_i2c_soft.c \
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drivers/serial.c \
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drivers/sound_beeper.c \
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|
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@ -45,14 +45,12 @@ You can also use the Command Line Interface (CLI) to set the mixer type:
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A low-pass filter can be enabled for the servos. It may be useful for avoiding structural modes in the airframe, for example. Currently it can only be configured via the CLI:
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1. Use `set servo_lowpass_freq_idx = nn` to select the cutoff frequency. Valid values range from 0 to 99.
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1. Use `set servo_lowpass_freq = nnn` to select the cutoff frequency. Valid values range from 10 to 400. This is a fraction of the loop frequency in 1/1000ths. For example, `40` means `0.040`.
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2. Use `set servo_lowpass_enable = 1` to enable filtering.
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The actual cutoff frequency is determined by the value of the `looptime` variable and the selected index.
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The formula is:
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`Frequency = 1000000 * (servo_lowpass_freq_idx + 1)*0.0025 / looptime )`
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For example, if `servo_lowpass_freq_idx` is set to 40, and looptime is set to the default of 3500 us (0.0035 s), the cutoff frequency will be 29.3 Hz.
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The cutoff frequency can be determined by the following formula:
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`Frequency = 1000 * servo_lowpass_freq / looptime`
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For example, if `servo_lowpass_freq` is set to 40, and looptime is set to the default of 3500 us, the cutoff frequency will be 11.43 Hz.
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@ -445,6 +445,8 @@ static void resetConf(void)
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currentProfile->mixerConfig.yaw_direction = 1;
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currentProfile->mixerConfig.tri_unarmed_servo = 1;
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currentProfile->mixerConfig.servo_lowpass_freq = 400;
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currentProfile->mixerConfig.servo_lowpass_enable = 0;
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// gimbal
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currentProfile->gimbalConfig.gimbal_flags = GIMBAL_NORMAL;
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@ -0,0 +1,117 @@
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/*
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||||
* This file is part of Cleanflight.
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*
|
||||
* Cleanflight is free software: you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation, either version 3 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* Cleanflight is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with Cleanflight. If not, see <http://www.gnu.org/licenses/>.
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||||
*/
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||||
|
||||
#include <stdbool.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <math.h>
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#include "flight/lowpass.h"
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//#define DEBUG_LOWPASS
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void generateLowpassCoeffs2(int16_t freq, lowpass_t *filter)
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{
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float fixedScaler;
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int i;
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// generates coefficients for a 2nd-order butterworth low-pass filter
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float freqf = (float)freq*0.001f;
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float omega = tanf((float)M_PI*freqf/2.0f);
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float scaling = 1.0f / (omega*omega + 1.4142136f*omega + 1.0f);
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#if defined(UNIT_TEST) && defined(DEBUG_LOWPASS)
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printf("lowpass cutoff: %f, omega: %f\n", freqf, omega);
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#endif
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filter->bf[0] = scaling * omega*omega;
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filter->bf[1] = 2.0f * filter->bf[0];
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filter->bf[2] = filter->bf[0];
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filter->af[0] = 1.0f;
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filter->af[1] = scaling * (2.0f * omega*omega - 2.0f);
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filter->af[2] = scaling * (omega*omega - 1.4142136f * omega + 1.0f);
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// Scale for fixed-point
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filter->input_bias = 1500; // Typical servo range is 1500 +/- 500
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filter->input_shift = 16;
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filter->coeff_shift = 24;
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fixedScaler = (float)(1ULL << filter->coeff_shift);
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for (i = 0; i < LOWPASS_NUM_COEF; i++) {
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filter->a[i] = LPF_ROUND(filter->af[i] * fixedScaler);
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filter->b[i] = LPF_ROUND(filter->bf[i] * fixedScaler);
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#if defined(UNIT_TEST) && defined(DEBUG_LOWPASS)
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printf("(%d) bf: %f af: %f b: %ld a: %ld\n", i,
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filter->bf[i], filter->af[i], filter->b[i], filter->a[i]);
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#endif
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}
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filter->freq = freq;
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}
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int32_t lowpassFixed(lowpass_t *filter, int32_t in, int16_t freq)
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{
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int16_t coefIdx;
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int64_t out;
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int32_t in_s;
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// Check to see if cutoff frequency changed
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if (freq != filter->freq) {
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filter->init = false;
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}
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// Initialize if needed
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if (!filter->init) {
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generateLowpassCoeffs2(freq, filter);
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for (coefIdx = 0; coefIdx < LOWPASS_NUM_COEF; coefIdx++) {
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filter->x[coefIdx] = (in - filter->input_bias) << filter->input_shift;
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filter->y[coefIdx] = (in - filter->input_bias) << filter->input_shift;
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}
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filter->init = true;
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}
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// Unbias input and scale
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in_s = (in - filter->input_bias) << filter->input_shift;
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// Delays
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for (coefIdx = LOWPASS_NUM_COEF-1; coefIdx > 0; coefIdx--) {
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filter->x[coefIdx] = filter->x[coefIdx-1];
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filter->y[coefIdx] = filter->y[coefIdx-1];
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}
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filter->x[0] = in_s;
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// Accumulate result
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out = filter->x[0] * filter->b[0];
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for (coefIdx = 1; coefIdx < LOWPASS_NUM_COEF; coefIdx++) {
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out -= filter->y[coefIdx] * filter->a[coefIdx];
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out += filter->x[coefIdx] * filter->b[coefIdx];
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}
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// Scale output by coefficient shift
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out >>= filter->coeff_shift;
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filter->y[0] = (int32_t)out;
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// Scale output by input shift and round
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out = (out + (1 << (filter->input_shift-1))) >> filter->input_shift;
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// Reapply bias
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out += filter->input_bias;
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return (int32_t)out;
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}
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@ -0,0 +1,41 @@
|
|||
/*
|
||||
* This file is part of Cleanflight.
|
||||
*
|
||||
* Cleanflight is free software: you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation, either version 3 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* Cleanflight is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with Cleanflight. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#pragma once
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||||
|
||||
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||||
#define LOWPASS_NUM_COEF 3
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#define LPF_ROUND(x) (x < 0 ? (x - 0.5f) : (x + 0.5f))
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typedef struct lowpass_t {
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bool init;
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int16_t freq; // Normalized freq in 1/1000ths
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float bf[LOWPASS_NUM_COEF];
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float af[LOWPASS_NUM_COEF];
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int64_t b[LOWPASS_NUM_COEF];
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int64_t a[LOWPASS_NUM_COEF];
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int16_t coeff_shift;
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int16_t input_shift;
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int32_t input_bias;
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float xf[LOWPASS_NUM_COEF];
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float yf[LOWPASS_NUM_COEF];
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int32_t x[LOWPASS_NUM_COEF];
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int32_t y[LOWPASS_NUM_COEF];
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} lowpass_t;
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void generateLowpassCoeffs2(int16_t freq, lowpass_t *filter);
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int32_t lowpassFixed(lowpass_t *filter, int32_t in, int16_t freq);
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@ -45,6 +45,7 @@
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#include "flight/mixer.h"
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#include "flight/pid.h"
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#include "flight/imu.h"
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#include "flight/lowpass.h"
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#include "config/runtime_config.h"
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#include "config/config.h"
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@ -54,10 +55,14 @@
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|||
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||||
#define AUX_FORWARD_CHANNEL_TO_SERVO_COUNT 4
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//#define MIXER_DEBUG
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extern int16_t debug[4];
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uint8_t motorCount = 0;
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int16_t motor[MAX_SUPPORTED_MOTORS];
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int16_t motor_disarmed[MAX_SUPPORTED_MOTORS];
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int16_t servo[MAX_SUPPORTED_SERVOS] = { 1500, 1500, 1500, 1500, 1500, 1500, 1500, 1500 };
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int16_t servo[MAX_SUPPORTED_SERVOS];
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static int useServo;
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@ -73,6 +78,7 @@ static gimbalConfig_t *gimbalConfig;
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static motorMixer_t currentMixer[MAX_SUPPORTED_MOTORS];
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static mixerMode_e currentMixerMode;
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static lowpass_t lowpassFilters[MAX_SUPPORTED_SERVOS];
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static const motorMixer_t mixerQuadX[] = {
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{ 1.0f, -1.0f, 1.0f, -1.0f }, // REAR_R
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@ -514,6 +520,11 @@ void mixTable(void)
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int16_t maxMotor;
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uint32_t i;
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// paranoia: give all servos a default command
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for (i = 0; i < MAX_SUPPORTED_SERVOS; i++) {
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servo[i] = DEFAULT_SERVO_MIDDLE;
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}
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if (motorCount > 3) {
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// prevent "yaw jump" during yaw correction
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axisPID[YAW] = constrain(axisPID[YAW], -100 - ABS(rcCommand[YAW]), +100 + ABS(rcCommand[YAW]));
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@ -660,3 +671,25 @@ bool isMixerUsingServos(void)
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{
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return useServo;
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}
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void filterServos(void)
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{
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int16_t servoIdx;
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|
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#if defined(MIXER_DEBUG)
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uint32_t startTime = micros();
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#endif
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|
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if (mixerConfig->servo_lowpass_enable) {
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for (servoIdx = 0; servoIdx < MAX_SUPPORTED_SERVOS; servoIdx++) {
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servo[servoIdx] = (int16_t)lowpassFixed(&lowpassFilters[servoIdx], servo[servoIdx], mixerConfig->servo_lowpass_freq);
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// Sanity check
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servo[servoIdx] = constrain(servo[servoIdx], servoConf[servoIdx].min, servoConf[servoIdx].max);
|
||||
}
|
||||
}
|
||||
#if defined(MIXER_DEBUG)
|
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debug[0] = (int16_t)(micros() - startTime);
|
||||
#endif
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -66,6 +66,8 @@ typedef struct mixer_t {
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typedef struct mixerConfig_s {
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||||
int8_t yaw_direction;
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||||
uint8_t tri_unarmed_servo; // send tail servo correction pulses even when unarmed
|
||||
int16_t servo_lowpass_freq; // lowpass servo filter frequency selection; 1/1000ths of loop freq
|
||||
int8_t servo_lowpass_enable; // enable/disable lowpass filter
|
||||
} mixerConfig_t;
|
||||
|
||||
typedef struct flight3DConfig_s {
|
||||
|
|
@ -101,3 +103,4 @@ void mixerResetMotors(void);
|
|||
void mixTable(void);
|
||||
void writeServos(void);
|
||||
void writeMotors(void);
|
||||
void filterServos(void);
|
||||
|
|
|
|||
|
|
@ -354,6 +354,8 @@ const clivalue_t valueTable[] = {
|
|||
{ "yaw_control_direction", VAR_INT8 | MASTER_VALUE, &masterConfig.yaw_control_direction, -1, 1 },
|
||||
{ "yaw_direction", VAR_INT8 | PROFILE_VALUE, &masterConfig.profile[0].mixerConfig.yaw_direction, -1, 1 },
|
||||
{ "tri_unarmed_servo", VAR_INT8 | PROFILE_VALUE, &masterConfig.profile[0].mixerConfig.tri_unarmed_servo, 0, 1 },
|
||||
{ "servo_lowpass_freq", VAR_INT16 | PROFILE_VALUE, &masterConfig.profile[0].mixerConfig.servo_lowpass_freq, 10, 400},
|
||||
{ "servo_lowpass_enable", VAR_INT8 | PROFILE_VALUE, &masterConfig.profile[0].mixerConfig.servo_lowpass_enable, 0, 1 },
|
||||
|
||||
{ "default_rate_profile", VAR_UINT8 | PROFILE_VALUE , &masterConfig.profile[0].defaultRateProfileIndex, 0, MAX_CONTROL_RATE_PROFILE_COUNT - 1 },
|
||||
{ "rc_rate", VAR_UINT8 | CONTROL_RATE_VALUE, &masterConfig.controlRateProfiles[0].rcRate8, 0, 250 },
|
||||
|
|
|
|||
|
|
@ -722,6 +722,7 @@ void loop(void)
|
|||
);
|
||||
|
||||
mixTable();
|
||||
filterServos();
|
||||
writeServos();
|
||||
writeMotors();
|
||||
|
||||
|
|
|
|||
|
|
@ -52,7 +52,8 @@ TESTS = \
|
|||
telemetry_hott_unittest \
|
||||
rc_controls_unittest \
|
||||
ledstrip_unittest \
|
||||
ws2811_unittest
|
||||
ws2811_unittest \
|
||||
lowpass_unittest
|
||||
|
||||
# All Google Test headers. Usually you shouldn't change this
|
||||
# definition.
|
||||
|
|
@ -319,6 +320,31 @@ ws2811_unittest : \
|
|||
|
||||
$(CXX) $(CXX_FLAGS) -lpthread $^ -o $(OBJECT_DIR)/$@
|
||||
|
||||
|
||||
$(OBJECT_DIR)/flight/lowpass.o : \
|
||||
$(USER_DIR)/flight/lowpass.c \
|
||||
$(USER_DIR)/flight/lowpass.h \
|
||||
$(GTEST_HEADERS)
|
||||
|
||||
@mkdir -p $(dir $@)
|
||||
$(CC) $(C_FLAGS) $(TEST_CFLAGS) -c $(USER_DIR)/flight/lowpass.c -o $@
|
||||
|
||||
$(OBJECT_DIR)/lowpass_unittest.o : \
|
||||
$(TEST_DIR)/lowpass_unittest.cc \
|
||||
$(USER_DIR)/flight/lowpass.h \
|
||||
$(GTEST_HEADERS)
|
||||
|
||||
@mkdir -p $(dir $@)
|
||||
$(CXX) $(CXX_FLAGS) $(TEST_CFLAGS) -c $(TEST_DIR)/lowpass_unittest.cc -o $@
|
||||
|
||||
lowpass_unittest : \
|
||||
$(OBJECT_DIR)/flight/lowpass.o \
|
||||
$(OBJECT_DIR)/lowpass_unittest.o \
|
||||
$(OBJECT_DIR)/gtest_main.a
|
||||
|
||||
$(CXX) $(CXX_FLAGS) -lpthread $^ -o $(OBJECT_DIR)/$@
|
||||
|
||||
|
||||
test: $(TESTS)
|
||||
set -e && for test in $(TESTS) ; do \
|
||||
$(OBJECT_DIR)/$$test; \
|
||||
|
|
|
|||
|
|
@ -0,0 +1,128 @@
|
|||
/*
|
||||
* This file is part of Cleanflight.
|
||||
*
|
||||
* Cleanflight is free software: you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation, either version 3 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* Cleanflight is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with Cleanflight. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
#include <stdint.h>
|
||||
#include <limits.h>
|
||||
|
||||
extern "C" {
|
||||
#include "flight/lowpass.h"
|
||||
}
|
||||
|
||||
static lowpass_t lowpassFilterReference;
|
||||
static lowpass_t lowpassFilter;
|
||||
|
||||
#include "unittest_macros.h"
|
||||
#include "gtest/gtest.h"
|
||||
|
||||
static float lowpassRef(lowpass_t *filter, float in, int16_t freq)
|
||||
{
|
||||
int16_t coefIdx;
|
||||
float out;
|
||||
|
||||
// Check to see if cutoff frequency changed
|
||||
if (freq != filter->freq) {
|
||||
filter->init = false;
|
||||
}
|
||||
|
||||
// Initialize if needed
|
||||
if (!filter->init) {
|
||||
generateLowpassCoeffs2(freq, filter);
|
||||
for (coefIdx = 0; coefIdx < LOWPASS_NUM_COEF; coefIdx++) {
|
||||
filter->xf[coefIdx] = in;
|
||||
filter->yf[coefIdx] = in;
|
||||
}
|
||||
filter->init = true;
|
||||
}
|
||||
|
||||
// Delays
|
||||
for (coefIdx = LOWPASS_NUM_COEF-1; coefIdx > 0; coefIdx--) {
|
||||
filter->xf[coefIdx] = filter->xf[coefIdx-1];
|
||||
filter->yf[coefIdx] = filter->yf[coefIdx-1];
|
||||
}
|
||||
filter->xf[0] = in;
|
||||
|
||||
// Accumulate result
|
||||
out = filter->xf[0] * filter->bf[0];
|
||||
for (coefIdx = 1; coefIdx < LOWPASS_NUM_COEF; coefIdx++) {
|
||||
out += filter->xf[coefIdx] * filter->bf[coefIdx];
|
||||
out -= filter->yf[coefIdx] * filter->af[coefIdx];
|
||||
}
|
||||
filter->yf[0] = out;
|
||||
|
||||
return out;
|
||||
}
|
||||
|
||||
TEST(LowpassTest, Lowpass)
|
||||
{
|
||||
int16_t servoCmds[3000];
|
||||
int16_t expectedOut[3000];
|
||||
int16_t referenceOut;
|
||||
int16_t filterOut;
|
||||
uint16_t sampleIdx;
|
||||
int16_t freq;
|
||||
|
||||
uint16_t sampleCount = sizeof(servoCmds) / sizeof(int16_t);
|
||||
|
||||
// generate inputs and expecteds
|
||||
for (sampleIdx = 0; sampleIdx < sampleCount; sampleIdx++) {
|
||||
if (sampleIdx < 1000) {
|
||||
servoCmds[sampleIdx] = 500;
|
||||
} else if (sampleIdx >= 1000 && sampleIdx < 2000) {
|
||||
servoCmds[sampleIdx] = 2500;
|
||||
} else {
|
||||
servoCmds[sampleIdx] = 1500;
|
||||
}
|
||||
|
||||
if ((sampleIdx >= 900 && sampleIdx < 1000) ||
|
||||
(sampleIdx >= 1900 && sampleIdx < 2000)||
|
||||
(sampleIdx >= 2900 && sampleIdx < 3000)) {
|
||||
expectedOut[sampleIdx] = servoCmds[sampleIdx];
|
||||
} else {
|
||||
expectedOut[sampleIdx] = -1;
|
||||
}
|
||||
}
|
||||
|
||||
// Test all frequencies
|
||||
for (freq = 10; freq <= 400; freq++) {
|
||||
printf("*** Testing freq: %d (%f)\n", freq, ((float)freq * 0.001f));
|
||||
|
||||
// Run tests
|
||||
for (sampleIdx = 0; sampleIdx < sampleCount; sampleIdx++)
|
||||
{
|
||||
// Filter under test
|
||||
filterOut = (int16_t)lowpassFixed(&lowpassFilter, servoCmds[sampleIdx], freq);
|
||||
|
||||
// Floating-point reference
|
||||
referenceOut = (int16_t)(lowpassRef(&lowpassFilterReference, (float)servoCmds[sampleIdx], freq) + 0.5f);
|
||||
|
||||
if (expectedOut[sampleIdx] >= 0) {
|
||||
EXPECT_EQ(filterOut, expectedOut[sampleIdx]);
|
||||
}
|
||||
// Some tolerance
|
||||
// TODO adjust precision to remove the need for this?
|
||||
EXPECT_LE(filterOut, referenceOut + 1);
|
||||
EXPECT_GE(filterOut, referenceOut - 1);
|
||||
} // for each sample
|
||||
} // for each freq
|
||||
}
|
||||
|
||||
// STUBS
|
||||
|
||||
extern "C" {
|
||||
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue