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betaflight/src/main/flight/pid.c
2016-01-07 02:11:47 +01:00

445 lines
18 KiB
C

/*
* 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 <stdbool.h>
#include <stdint.h>
#include <math.h>
#include <platform.h>
#include "build_config.h"
#include "debug.h"
#include "common/axis.h"
#include "common/maths.h"
#include "common/filter.h"
#include "drivers/sensor.h"
#include "drivers/gyro_sync.h"
#include "drivers/accgyro.h"
#include "sensors/sensors.h"
#include "sensors/gyro.h"
#include "sensors/acceleration.h"
#include "rx/rx.h"
#include "io/rc_controls.h"
#include "io/gps.h"
#include "flight/pid.h"
#include "flight/imu.h"
#include "flight/navigation.h"
#include "flight/gtune.h"
#include "config/runtime_config.h"
extern float dT;
extern bool motorLimitReached;
extern bool allowITermShrinkOnly;
int16_t axisPID[3];
#ifdef BLACKBOX
int32_t axisPID_P[3], axisPID_I[3], axisPID_D[3];
#endif
// PIDweight is a scale factor for PIDs which is derived from the throttle and TPA setting, and 100 = 100% scale means no PID reduction
uint8_t dynP8[3], dynI8[3], dynD8[3], PIDweight[3];
static int32_t errorGyroI[3] = { 0, 0, 0 };
static float errorGyroIf[3] = { 0.0f, 0.0f, 0.0f };
static uint8_t deltaTotalSamples = 0;
static void pidRewrite(pidProfile_t *pidProfile, controlRateConfig_t *controlRateConfig,
uint16_t max_angle_inclination, rollAndPitchTrims_t *angleTrim, rxConfig_t *rxConfig);
typedef void (*pidControllerFuncPtr)(pidProfile_t *pidProfile, controlRateConfig_t *controlRateConfig,
uint16_t max_angle_inclination, rollAndPitchTrims_t *angleTrim, rxConfig_t *rxConfig); // pid controller function prototype
pidControllerFuncPtr pid_controller = pidRewrite; // which pid controller are we using, defaultMultiWii
void pidResetErrorGyro(void)
{
errorGyroI[ROLL] = 0;
errorGyroI[PITCH] = 0;
errorGyroI[YAW] = 0;
errorGyroIf[ROLL] = 0.0f;
errorGyroIf[PITCH] = 0.0f;
errorGyroIf[YAW] = 0.0f;
}
void setPidDeltaSamples(uint8_t filter) {
if (!filter) {
if (targetLooptime < 1000) {
deltaTotalSamples = 8;
} else {
deltaTotalSamples = 4;
}
} else {
deltaTotalSamples = 1;
}
}
void airModePlus(airModePlus_t *axisState, int axis, pidProfile_t *pidProfile, float referenceTerm) {
float rcCommandReflection = (float)rcCommand[axis] / 500.0f;
//Ki scaler
axisState->iTermScaler = constrainf(1.0f - (1.5f * ABS(rcCommandReflection)), 0.0f, 1.0f);
//dynamic Ki handler
if (axisState->isCurrentlyAtZero) {
if (axisState->previousReferenceIsPositive ^ IS_POSITIVE(referenceTerm)) {
axisState->isCurrentlyAtZero = false;
} else {
axisState->iTermScaler = 0;
errorGyroIf[axis] = 0;
errorGyroI[axis] = 0;
}
}
if (!axisState->iTermScaler) {
if (!axisState->isCurrentlyAtZero) {
if (IS_POSITIVE(referenceTerm)) {
axisState->previousReferenceIsPositive = true;
} else {
axisState->previousReferenceIsPositive = false;
}
} else {
axisState->isCurrentlyAtZero = true;
}
}
if (axis != YAW && pidProfile->airModeInsaneAcrobilityFactor) {
axisState->wowFactor = 1.0f - (ABS(rcCommandReflection) * ((float)pidProfile->airModeInsaneAcrobilityFactor / 100.0f)); //0-1f
axisState->factor = (axisState->wowFactor * rcCommandReflection) * 1000;
} else {
axisState->wowFactor = 1;
axisState->factor = 0;
}
}
const angle_index_t rcAliasToAngleIndexMap[] = { AI_ROLL, AI_PITCH };
static filterStatePt1_t DTermState[3];
static airModePlus_t airModePlusAxisState[3];
static void pidLuxFloat(pidProfile_t *pidProfile, controlRateConfig_t *controlRateConfig,
uint16_t max_angle_inclination, rollAndPitchTrims_t *angleTrim, rxConfig_t *rxConfig)
{
float RateError, AngleRate, gyroRate;
float ITerm,PTerm,DTerm;
static float lastGyroRate[3];
static float lastError[3];
static float previousDelta[3][8];
float delta, deltaSum;
int axis, deltaCount;
float horizonLevelStrength = 1;
static float previousErrorGyroIf[3] = { 0.0f, 0.0f, 0.0f };
if (!deltaTotalSamples) setPidDeltaSamples(pidProfile->dterm_cut_hz);
if (FLIGHT_MODE(HORIZON_MODE)) {
// Figure out the raw stick positions
const int32_t stickPosAil = ABS(getRcStickDeflection(FD_ROLL, rxConfig->midrc));
const int32_t stickPosEle = ABS(getRcStickDeflection(FD_PITCH, rxConfig->midrc));
const int32_t mostDeflectedPos = MAX(stickPosAil, stickPosEle);
// Progressively turn off the horizon self level strength as the stick is banged over
horizonLevelStrength = (float)(500 - mostDeflectedPos) / 500; // 1 at centre stick, 0 = max stick deflection
if(pidProfile->H_sensitivity == 0){
horizonLevelStrength = 0;
} else {
horizonLevelStrength = constrainf(((horizonLevelStrength - 1) * (100 / pidProfile->H_sensitivity)) + 1, 0, 1);
}
}
// ----------PID controller----------
for (axis = 0; axis < 3; axis++) {
// -----Get the desired angle rate depending on flight mode
uint8_t rate = controlRateConfig->rates[axis];
if (axis == FD_YAW) {
// YAW is always gyro-controlled (MAG correction is applied to rcCommand) 100dps to 1100dps max yaw rate
AngleRate = (float)((rate + 10) * rcCommand[YAW]) / 50.0f;
} else {
// ACRO mode, control is GYRO based, direct sticks control is applied to rate PID
AngleRate = (float)((rate + 20) * rcCommand[axis]) / 50.0f; // 200dps to 1200dps max roll/pitch rate
if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE)) {
// calculate error angle and limit the angle to the max inclination
#ifdef GPS
const float errorAngle = (constrain(rcCommand[axis] + GPS_angle[axis], -((int) max_angle_inclination),
+max_angle_inclination) - attitude.raw[axis] + angleTrim->raw[axis]) / 10.0f; // 16 bits is ok here
#else
const float errorAngle = (constrain(rcCommand[axis], -((int) max_angle_inclination),
+max_angle_inclination) - attitude.raw[axis] + angleTrim->raw[axis]) / 10.0f; // 16 bits is ok here
#endif
if (FLIGHT_MODE(ANGLE_MODE)) {
// ANGLE mode - control is angle based, so control loop is needed
AngleRate = errorAngle * pidProfile->A_level;
} else {
// HORIZON mode - direct sticks control is applied to rate PID
// mix up angle error to desired AngleRate to add a little auto-level feel
AngleRate += errorAngle * pidProfile->H_level * horizonLevelStrength;
}
}
}
gyroRate = gyroADC[axis] * gyro.scale; // gyro output scaled to dps
// --------low-level gyro-based PID. ----------
// Used in stand-alone mode for ACRO, controlled by higher level regulators in other modes
// -----calculate scaled error.AngleRates
// multiplication of rcCommand corresponds to changing the sticks scaling here
RateError = AngleRate - gyroRate;
// -----calculate P component
PTerm = RateError * pidProfile->P_f[axis] * PIDweight[axis] / 100;
// -----calculate I component.
errorGyroIf[axis] = constrainf(errorGyroIf[axis] + RateError * dT * pidProfile->I_f[axis] * 10, -250.0f, 250.0f);
if (IS_RC_MODE_ACTIVE(BOXAIRMODE)) {
airModePlus(&airModePlusAxisState[axis], axis, pidProfile, PTerm);
errorGyroIf[axis] *= airModePlusAxisState[axis].iTermScaler;
}
if (allowITermShrinkOnly || motorLimitReached) {
if (ABS(errorGyroIf[axis]) < ABS(previousErrorGyroIf[axis])) {
previousErrorGyroIf[axis] = errorGyroIf[axis];
} else {
errorGyroIf[axis] = constrain(errorGyroIf[axis], -ABS(previousErrorGyroIf[axis]), ABS(previousErrorGyroIf[axis]));
}
} else {
previousErrorGyroIf[axis] = errorGyroIf[axis];
}
// limit maximum integrator value to prevent WindUp - accumulating extreme values when system is saturated.
// I coefficient (I8) moved before integration to make limiting independent from PID settings
ITerm = errorGyroIf[axis];
//-----calculate D-term
if (pidProfile->delta_from_gyro_error || axis == YAW) {
delta = -(gyroRate - lastGyroRate[axis]); // 16 bits is ok here, the dif between 2 consecutive gyro reads is limited to 800
lastGyroRate[axis] = gyroRate;
} else {
delta = RateError - lastError[axis];
lastError[axis] = RateError;
}
// Correct difference by cycle time. Cycle time is jittery (can be different 2 times), so calculated difference
// would be scaled by different dt each time. Division by dT fixes that.
delta *= (1.0f / dT);
deltaSum = 0;
if (pidProfile->dterm_cut_hz) {
// Dterm low pass
deltaSum = filterApplyPt1(delta, &DTermState[axis], pidProfile->dterm_cut_hz, dT);
}
// Apply moving average
if (deltaTotalSamples > 1) {
for (deltaCount = deltaTotalSamples-1; deltaCount > 0; deltaCount--) previousDelta[axis][deltaCount] = previousDelta[axis][deltaCount-1];
previousDelta[axis][0] = delta;
for (deltaCount = 0; deltaCount < deltaTotalSamples; deltaCount++) deltaSum += previousDelta[axis][deltaCount];
deltaSum = (deltaSum / deltaTotalSamples);
}
DTerm = constrainf(deltaSum * pidProfile->D_f[axis] * PIDweight[axis] / 100, -300.0f, 300.0f);
// -----calculate total PID output
axisPID[axis] = constrain(lrintf(PTerm + ITerm + DTerm), -1000, 1000);
if (IS_RC_MODE_ACTIVE(BOXAIRMODE)) {
axisPID[axis] = lrintf(airModePlusAxisState[axis].factor + airModePlusAxisState[axis].wowFactor * axisPID[axis]);
}
#ifdef GTUNE
if (FLIGHT_MODE(GTUNE_MODE) && ARMING_FLAG(ARMED)) {
calculate_Gtune(axis);
}
#endif
#ifdef BLACKBOX
axisPID_P[axis] = PTerm;
axisPID_I[axis] = ITerm;
axisPID_D[axis] = DTerm;
#endif
}
}
static void pidRewrite(pidProfile_t *pidProfile, controlRateConfig_t *controlRateConfig, uint16_t max_angle_inclination,
rollAndPitchTrims_t *angleTrim, rxConfig_t *rxConfig)
{
UNUSED(rxConfig);
int axis, deltaCount;
int32_t delta, deltaSum;
static int32_t previousDelta[3][8];
int32_t PTerm, ITerm, DTerm;
static int32_t lastError[3] = { 0, 0, 0 };
static int32_t lastGyroRate[3] = { 0, 0, 0 };
static int32_t previousErrorGyroI[3] = { 0, 0, 0 };
int32_t AngleRateTmp, RateError, gyroRate;
int8_t horizonLevelStrength = 100;
if (!deltaTotalSamples) setPidDeltaSamples(pidProfile->dterm_cut_hz);
if (FLIGHT_MODE(HORIZON_MODE)) {
// Figure out the raw stick positions
const int32_t stickPosAil = ABS(getRcStickDeflection(FD_ROLL, rxConfig->midrc));
const int32_t stickPosEle = ABS(getRcStickDeflection(FD_PITCH, rxConfig->midrc));
const int32_t mostDeflectedPos = MAX(stickPosAil, stickPosEle);
// Progressively turn off the horizon self level strength as the stick is banged over
horizonLevelStrength = (500 - mostDeflectedPos) / 5; // 100 at centre stick, 0 = max stick deflection
// Using Level D as a Sensitivity for Horizon. 0 more level to 255 more rate. Default value of 100 seems to work fine.
// For more rate mode increase D and slower flips and rolls will be possible
horizonLevelStrength = constrain((10 * (horizonLevelStrength - 100) * (10 * pidProfile->D8[PIDLEVEL] / 80) / 100) + 100, 0, 100);
}
// ----------PID controller----------
for (axis = 0; axis < 3; axis++) {
uint8_t rate = controlRateConfig->rates[axis];
// -----Get the desired angle rate depending on flight mode
if (axis == FD_YAW) {
// YAW is always gyro-controlled (MAG correction is applied to rcCommand)
AngleRateTmp = ((int32_t)(rate + 27) * rcCommand[YAW]) >> 5;
} else {
AngleRateTmp = ((int32_t)(rate + 27) * rcCommand[axis]) >> 4;
if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE)) {
// calculate error angle and limit the angle to max configured inclination
#ifdef GPS
const int32_t errorAngle = constrain(2 * rcCommand[axis] + GPS_angle[axis], -((int) max_angle_inclination),
+max_angle_inclination) - attitude.raw[axis] + angleTrim->raw[axis];
#else
const int32_t errorAngle = constrain(2 * rcCommand[axis], -((int) max_angle_inclination),
+max_angle_inclination) - attitude.raw[axis] + angleTrim->raw[axis];
#endif
if (FLIGHT_MODE(ANGLE_MODE)) {
// ANGLE mode - control is angle based, so control loop is needed
AngleRateTmp = (errorAngle * pidProfile->P8[PIDLEVEL]) >> 4;
} else {
// HORIZON mode - mix up angle error to desired AngleRateTmp to add a little auto-level feel,
// horizonLevelStrength is scaled to the stick input
AngleRateTmp += (errorAngle * pidProfile->I8[PIDLEVEL] * horizonLevelStrength / 100) >> 4;
}
}
}
// --------low-level gyro-based PID. ----------
// Used in stand-alone mode for ACRO, controlled by higher level regulators in other modes
// -----calculate scaled error.AngleRates
// multiplication of rcCommand corresponds to changing the sticks scaling here
gyroRate = gyroADC[axis] / 4;
RateError = AngleRateTmp - gyroRate;
// -----calculate P component
PTerm = (RateError * pidProfile->P8[axis] * PIDweight[axis] / 100) >> 7;
// -----calculate I component
// there should be no division before accumulating the error to integrator, because the precision would be reduced.
// Precision is critical, as I prevents from long-time drift. Thus, 32 bits integrator is used.
// Time correction (to avoid different I scaling for different builds based on average cycle time)
// is normalized to cycle time = 2048.
errorGyroI[axis] = errorGyroI[axis] + ((RateError * (uint16_t)targetLooptime) >> 11) * pidProfile->I8[axis];
// limit maximum integrator value to prevent WindUp - accumulating extreme values when system is saturated.
// I coefficient (I8) moved before integration to make limiting independent from PID settings
errorGyroI[axis] = constrain(errorGyroI[axis], (int32_t) - GYRO_I_MAX << 13, (int32_t) + GYRO_I_MAX << 13);
if (IS_RC_MODE_ACTIVE(BOXAIRMODE)) {
airModePlus(&airModePlusAxisState[axis], axis, pidProfile, (float) PTerm);
errorGyroI[axis] *= airModePlusAxisState[axis].iTermScaler;
}
ITerm = errorGyroI[axis] >> 13;
if (allowITermShrinkOnly || motorLimitReached) {
if (ABS(errorGyroI[axis]) < ABS(previousErrorGyroI[axis])) {
previousErrorGyroI[axis] = errorGyroI[axis];
} else {
errorGyroI[axis] = constrain(errorGyroI[axis], -ABS(previousErrorGyroI[axis]), ABS(previousErrorGyroI[axis]));
}
} else {
previousErrorGyroI[axis] = errorGyroI[axis];
}
//-----calculate D-term
if (pidProfile->delta_from_gyro_error || axis == YAW) { // quick and dirty solution for testing
delta = -(gyroRate - lastGyroRate[axis]); // 16 bits is ok here, the dif between 2 consecutive gyro reads is limited to 800
lastGyroRate[axis] = gyroRate;
} else {
delta = RateError - lastError[axis]; // 16 bits is ok here, the dif between 2 consecutive gyro reads is limited to 800
lastError[axis] = RateError;
}
// Correct difference by cycle time. Cycle time is jittery (can be different 2 times), so calculated difference
// would be scaled by different dt each time. Division by dT fixes that.
delta = (delta * ((uint16_t) 0xFFFF / ((uint16_t)targetLooptime >> 4))) >> 6;
// Apply moving average
deltaSum = 0;
if (pidProfile->dterm_cut_hz) {
// Dterm low pass
deltaSum = filterApplyPt1(delta, &DTermState[axis], pidProfile->dterm_cut_hz, dT);
}
if (deltaTotalSamples > 1) {
for (deltaCount = deltaTotalSamples-1; deltaCount > 0; deltaCount--) previousDelta[axis][deltaCount] = previousDelta[axis][deltaCount-1];
previousDelta[axis][0] = delta;
for (deltaCount = 0; deltaCount < deltaTotalSamples; deltaCount++) deltaSum += previousDelta[axis][deltaCount];
}
deltaSum = (deltaSum / deltaTotalSamples) * 3; // get old scaling by multiplying with 3
DTerm = (deltaSum * pidProfile->D8[axis] * PIDweight[axis] / 100) >> 8;
// -----calculate total PID output
axisPID[axis] = PTerm + ITerm + DTerm;
if (IS_RC_MODE_ACTIVE(BOXAIRMODE)) {
axisPID[axis] = lrintf(airModePlusAxisState[axis].factor + airModePlusAxisState[axis].wowFactor * axisPID[axis]);
}
#ifdef GTUNE
if (FLIGHT_MODE(GTUNE_MODE) && ARMING_FLAG(ARMED)) {
calculate_Gtune(axis);
}
#endif
#ifdef BLACKBOX
axisPID_P[axis] = PTerm;
axisPID_I[axis] = ITerm;
axisPID_D[axis] = DTerm;
#endif
}
}
void pidSetController(pidControllerType_e type)
{
switch (type) {
default:
case PID_CONTROLLER_MWREWRITE:
pid_controller = pidRewrite;
break;
case PID_CONTROLLER_LUX_FLOAT:
pid_controller = pidLuxFloat;
}
}