src/main/flight/pid.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stdbool.h>
  22 #include <stdint.h>
  23 #include <string.h>
  24 #include <math.h>
  25
  26 #include "platform.h"
  27
  28 #include "build/build_config.h"
  29 #include "build/debug.h"
  30
  31 #include "common/axis.h"
  32 #include "common/maths.h"
  33 #include "common/filter.h"
  34
  35 #include "config/config_reset.h"
  36 #include "pg/pg.h"
  37 #include "pg/pg_ids.h"
  38
  39 #include "drivers/sound_beeper.h"
  40 #include "drivers/time.h"
  41
  42 #include "fc/fc_core.h"
  43 #include "fc/fc_rc.h"
  44
  45 #include "fc/rc_controls.h"
  46 #include "fc/runtime_config.h"
  47
  48 #include "flight/pid.h"
  49 #include "flight/imu.h"
  50 #include "flight/gps_rescue.h"
  51 #include "flight/mixer.h"
  52
  53 #include "io/gps.h"
  54
  55 #include "sensors/gyro.h"
  56 #include "sensors/acceleration.h"
  57
  58
  59 FAST_RAM_ZERO_INIT uint32_t targetPidLooptime;
  60 FAST_RAM_ZERO_INIT pidAxisData_t pidData[XYZ_AXIS_COUNT];
  61
  62 static FAST_RAM_ZERO_INIT bool pidStabilisationEnabled;
  63
  64 static FAST_RAM_ZERO_INIT bool inCrashRecoveryMode = false;
  65
  66 static FAST_RAM_ZERO_INIT float dT;
  67 static FAST_RAM_ZERO_INIT float pidFrequency;
  68
  69 PG_REGISTER_WITH_RESET_TEMPLATE(pidConfig_t, pidConfig, PG_PID_CONFIG, 2);
  70
  71 #ifdef STM32F10X
  72 #define PID_PROCESS_DENOM_DEFAULT       1
  73 #elif defined(USE_GYRO_SPI_MPU6000) || defined(USE_GYRO_SPI_MPU6500)  || defined(USE_GYRO_SPI_ICM20689)
  74 #define PID_PROCESS_DENOM_DEFAULT       4
  75 #else
  76 #define PID_PROCESS_DENOM_DEFAULT       2
  77 #endif
  78
  79 #ifdef USE_RUNAWAY_TAKEOFF
  80 PG_RESET_TEMPLATE(pidConfig_t, pidConfig,
  81     .pid_process_denom = PID_PROCESS_DENOM_DEFAULT,
  82     .runaway_takeoff_prevention = true,
  83     .runaway_takeoff_deactivate_throttle = 25,  // throttle level % needed to accumulate deactivation time
  84     .runaway_takeoff_deactivate_delay = 500     // Accumulated time (in milliseconds) before deactivation in successful takeoff
  85 );
  86 #else
  87 PG_RESET_TEMPLATE(pidConfig_t, pidConfig,
  88     .pid_process_denom = PID_PROCESS_DENOM_DEFAULT
  89 );
  90 #endif
  91
  92 #ifdef USE_ACRO_TRAINER
  93 #define ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT 500.0f  // Max gyro rate for lookahead time scaling
  94 #define ACRO_TRAINER_SETPOINT_LIMIT       1000.0f // Limit the correcting setpoint
  95 #endif // USE_ACRO_TRAINER
  96
  97 PG_REGISTER_ARRAY_WITH_RESET_FN(pidProfile_t, MAX_PROFILE_COUNT, pidProfiles, PG_PID_PROFILE, 4);
  98
  99 void resetPidProfile(pidProfile_t *pidProfile)
 100 {
 101     RESET_CONFIG(pidProfile_t, pidProfile,
 102         .pid = {
 103             [PID_ROLL] =  { 46, 45, 25 },
 104             [PID_PITCH] = { 50, 50, 27 },
 105             [PID_YAW] =   { 65, 45, 0 },
 106             [PID_ALT] =   { 50, 0, 0 },
 107             [PID_POS] =   { 15, 0, 0 },     // POSHOLD_P * 100, POSHOLD_I * 100,
 108             [PID_POSR] =  { 34, 14, 53 },   // POSHOLD_RATE_P * 10, POSHOLD_RATE_I * 100, POSHOLD_RATE_D * 1000,
 109             [PID_NAVR] =  { 25, 33, 83 },   // NAV_P * 10, NAV_I * 100, NAV_D * 1000
 110             [PID_LEVEL] = { 50, 50, 75 },
 111             [PID_MAG] =   { 40, 0, 0 },
 112             [PID_VEL] =   { 55, 55, 75 }
 113         },
 114
 115         .pidSumLimit = PIDSUM_LIMIT,
 116         .pidSumLimitYaw = PIDSUM_LIMIT_YAW,
 117         .yaw_lowpass_hz = 0,
 118         .dterm_lowpass_hz = 100,    // dual PT1 filtering ON by default
 119         .dterm_lowpass2_hz = 200,   // second Dterm LPF ON by default
 120         .dterm_notch_hz = 0,
 121         .dterm_notch_cutoff = 160,
 122         .dterm_filter_type = FILTER_PT1,
 123         .itermWindupPointPercent = 40,
 124         .vbatPidCompensation = 0,
 125         .pidAtMinThrottle = PID_STABILISATION_ON,
 126         .levelAngleLimit = 55,
 127         .setpointRelaxRatio = 0,
 128         .dtermSetpointWeight = 60,
 129         .yawRateAccelLimit = 100,
 130         .rateAccelLimit = 0,
 131         .itermThrottleThreshold = 350,
 132         .itermAcceleratorGain = 5000,
 133         .crash_time = 500,          // ms
 134         .crash_delay = 0,           // ms
 135         .crash_recovery_angle = 10, // degrees
 136         .crash_recovery_rate = 100, // degrees/second
 137         .crash_dthreshold = 50,     // degrees/second/second
 138         .crash_gthreshold = 400,    // degrees/second
 139         .crash_setpoint_threshold = 350, // degrees/second
 140         .crash_recovery = PID_CRASH_RECOVERY_OFF, // off by default
 141         .horizon_tilt_effect = 75,
 142         .horizon_tilt_expert_mode = false,
 143         .crash_limit_yaw = 200,
 144         .itermLimit = 150,
 145         .throttle_boost = 5,
 146         .throttle_boost_cutoff = 15,
 147         .iterm_rotation = true,
 148         .smart_feedforward = false,
 149         .iterm_relax = ITERM_RELAX_OFF,
 150         .iterm_relax_cutoff = 11,
 151         .iterm_relax_type = ITERM_RELAX_GYRO,
 152         .acro_trainer_angle_limit = 20,
 153         .acro_trainer_lookahead_ms = 50,
 154         .acro_trainer_debug_axis = FD_ROLL,
 155         .acro_trainer_gain = 75,
 156         .abs_control_gain = 0,
 157         .abs_control_limit = 90,
 158         .abs_control_error_limit = 20,
 159     );
 160 }
 161
 162 void pgResetFn_pidProfiles(pidProfile_t *pidProfiles)
 163 {
 164     for (int i = 0; i < MAX_PROFILE_COUNT; i++) {
 165         resetPidProfile(&pidProfiles[i]);
 166     }
 167 }
 168
 169 static void pidSetTargetLooptime(uint32_t pidLooptime)
 170 {
 171     targetPidLooptime = pidLooptime;
 172     dT = targetPidLooptime * 1e-6f;
 173     pidFrequency = 1.0f / dT;
 174 }
 175
 176 static FAST_RAM float itermAccelerator = 1.0f;
 177
 178 void pidSetItermAccelerator(float newItermAccelerator)
 179 {
 180     itermAccelerator = newItermAccelerator;
 181 }
 182
 183 float pidItermAccelerator(void)
 184 {
 185     return itermAccelerator;
 186 }
 187
 188 void pidStabilisationState(pidStabilisationState_e pidControllerState)
 189 {
 190     pidStabilisationEnabled = (pidControllerState == PID_STABILISATION_ON) ? true : false;
 191 }
 192
 193 const angle_index_t rcAliasToAngleIndexMap[] = { AI_ROLL, AI_PITCH };
 194
 195 typedef union dtermLowpass_u {
 196     pt1Filter_t pt1Filter;
 197     biquadFilter_t biquadFilter;
 198 } dtermLowpass_t;
 199
 200 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermNotchApplyFn;
 201 static FAST_RAM_ZERO_INIT biquadFilter_t dtermNotch[2];
 202 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpassApplyFn;
 203 static FAST_RAM_ZERO_INIT dtermLowpass_t dtermLowpass[2];
 204 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpass2ApplyFn;
 205 static FAST_RAM_ZERO_INIT pt1Filter_t dtermLowpass2[2];
 206 static FAST_RAM_ZERO_INIT filterApplyFnPtr ptermYawLowpassApplyFn;
 207 static FAST_RAM_ZERO_INIT pt1Filter_t ptermYawLowpass;
 208 #if defined(USE_ITERM_RELAX)
 209 static FAST_RAM_ZERO_INIT pt1Filter_t windupLpf[XYZ_AXIS_COUNT];
 210 static FAST_RAM_ZERO_INIT uint8_t itermRelax;
 211 static FAST_RAM_ZERO_INIT uint8_t itermRelaxType;
 212 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoff;
 213 #endif
 214
 215 #ifdef USE_RC_SMOOTHING_FILTER
 216 static FAST_RAM_ZERO_INIT pt1Filter_t setpointDerivativePt1[2];
 217 static FAST_RAM_ZERO_INIT biquadFilter_t setpointDerivativeBiquad[2];
 218 static FAST_RAM_ZERO_INIT bool setpointDerivativeLpfInitialized;
 219 static FAST_RAM_ZERO_INIT uint8_t rcSmoothingDebugAxis;
 220 static FAST_RAM_ZERO_INIT uint8_t rcSmoothingFilterType;
 221 #endif // USE_RC_SMOOTHING_FILTER
 222
 223 void pidInitFilters(const pidProfile_t *pidProfile)
 224 {
 225     BUILD_BUG_ON(FD_YAW != 2); // only setting up Dterm filters on roll and pitch axes, so ensure yaw axis is 2
 226
 227     if (targetPidLooptime == 0) {
 228         // no looptime set, so set all the filters to null
 229         dtermNotchApplyFn = nullFilterApply;
 230         dtermLowpassApplyFn = nullFilterApply;
 231         ptermYawLowpassApplyFn = nullFilterApply;
 232         return;
 233     }
 234
 235     const uint32_t pidFrequencyNyquist = pidFrequency / 2; // No rounding needed
 236
 237     uint16_t dTermNotchHz;
 238     if (pidProfile->dterm_notch_hz <= pidFrequencyNyquist) {
 239         dTermNotchHz = pidProfile->dterm_notch_hz;
 240     } else {
 241         if (pidProfile->dterm_notch_cutoff < pidFrequencyNyquist) {
 242             dTermNotchHz = pidFrequencyNyquist;
 243         } else {
 244             dTermNotchHz = 0;
 245         }
 246     }
 247
 248     if (dTermNotchHz != 0 && pidProfile->dterm_notch_cutoff != 0) {
 249         dtermNotchApplyFn = (filterApplyFnPtr)biquadFilterApply;
 250         const float notchQ = filterGetNotchQ(dTermNotchHz, pidProfile->dterm_notch_cutoff);
 251         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 252             biquadFilterInit(&dtermNotch[axis], dTermNotchHz, targetPidLooptime, notchQ, FILTER_NOTCH);
 253         }
 254     } else {
 255         dtermNotchApplyFn = nullFilterApply;
 256     }
 257
 258     //2nd Dterm Lowpass Filter
 259     if (pidProfile->dterm_lowpass2_hz == 0 || pidProfile->dterm_lowpass2_hz > pidFrequencyNyquist) {
 260         dtermLowpass2ApplyFn = nullFilterApply;
 261     } else {
 262         dtermLowpass2ApplyFn = (filterApplyFnPtr)pt1FilterApply;
 263         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 264             pt1FilterInit(&dtermLowpass2[axis], pt1FilterGain(pidProfile->dterm_lowpass2_hz, dT));
 265         }
 266     }
 267
 268     if (pidProfile->dterm_lowpass_hz == 0 || pidProfile->dterm_lowpass_hz > pidFrequencyNyquist) {
 269         dtermLowpassApplyFn = nullFilterApply;
 270     } else {
 271         switch (pidProfile->dterm_filter_type) {
 272         default:
 273             dtermLowpassApplyFn = nullFilterApply;
 274             break;
 275         case FILTER_PT1:
 276             dtermLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 277             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 278                 pt1FilterInit(&dtermLowpass[axis].pt1Filter, pt1FilterGain(pidProfile->dterm_lowpass_hz, dT));
 279             }
 280             break;
 281         case FILTER_BIQUAD:
 282             dtermLowpassApplyFn = (filterApplyFnPtr)biquadFilterApply;
 283             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 284                 biquadFilterInitLPF(&dtermLowpass[axis].biquadFilter, pidProfile->dterm_lowpass_hz, targetPidLooptime);
 285             }
 286             break;
 287         }
 288     }
 289
 290     if (pidProfile->yaw_lowpass_hz == 0 || pidProfile->yaw_lowpass_hz > pidFrequencyNyquist) {
 291         ptermYawLowpassApplyFn = nullFilterApply;
 292     } else {
 293         ptermYawLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 294         pt1FilterInit(&ptermYawLowpass, pt1FilterGain(pidProfile->yaw_lowpass_hz, dT));
 295     }
 296
 297 #if defined(USE_THROTTLE_BOOST)
 298     pt1FilterInit(&throttleLpf, pt1FilterGain(pidProfile->throttle_boost_cutoff, dT));
 299 #endif
 300 #if defined(USE_ITERM_RELAX)
 301     if (itermRelax) {
 302         for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 303             pt1FilterInit(&windupLpf[i], pt1FilterGain(itermRelaxCutoff, dT));
 304         }
 305     }
 306 #endif
 307 }
 308
 309 #ifdef USE_RC_SMOOTHING_FILTER
 310 void pidInitSetpointDerivativeLpf(uint16_t filterCutoff, uint8_t debugAxis, uint8_t filterType)
 311 {
 312     rcSmoothingDebugAxis = debugAxis;
 313     rcSmoothingFilterType = filterType;
 314     if ((filterCutoff > 0) && (rcSmoothingFilterType != RC_SMOOTHING_DERIVATIVE_OFF)) {
 315         setpointDerivativeLpfInitialized = true;
 316         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 317             switch (rcSmoothingFilterType) {
 318                 case RC_SMOOTHING_DERIVATIVE_PT1:
 319                     pt1FilterInit(&setpointDerivativePt1[axis], pt1FilterGain(filterCutoff, dT));
 320                     break;
 321                 case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 322                     biquadFilterInitLPF(&setpointDerivativeBiquad[axis], filterCutoff, targetPidLooptime);
 323                     break;
 324             }
 325         }
 326     }
 327 }
 328
 329 void pidUpdateSetpointDerivativeLpf(uint16_t filterCutoff)
 330 {
 331     if ((filterCutoff > 0) && (rcSmoothingFilterType != RC_SMOOTHING_DERIVATIVE_OFF)) {
 332         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 333             switch (rcSmoothingFilterType) {
 334                 case RC_SMOOTHING_DERIVATIVE_PT1:
 335                     pt1FilterUpdateCutoff(&setpointDerivativePt1[axis], pt1FilterGain(filterCutoff, dT));
 336                     break;
 337                 case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 338                     biquadFilterUpdateLPF(&setpointDerivativeBiquad[axis], filterCutoff, targetPidLooptime);
 339                     break;
 340             }
 341         }
 342     }
 343 }
 344 #endif // USE_RC_SMOOTHING_FILTER
 345
 346 typedef struct pidCoefficient_s {
 347     float Kp;
 348     float Ki;
 349     float Kd;
 350 } pidCoefficient_t;
 351
 352 static FAST_RAM_ZERO_INIT pidCoefficient_t pidCoefficient[3];
 353 static FAST_RAM_ZERO_INIT float maxVelocity[3];
 354 static FAST_RAM_ZERO_INIT float relaxFactor;
 355 static FAST_RAM_ZERO_INIT float dtermSetpointWeight;
 356 static FAST_RAM_ZERO_INIT float levelGain, horizonGain, horizonTransition, horizonCutoffDegrees, horizonFactorRatio;
 357 static FAST_RAM_ZERO_INIT float ITermWindupPointInv;
 358 static FAST_RAM_ZERO_INIT uint8_t horizonTiltExpertMode;
 359 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeLimitUs;
 360 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeDelayUs;
 361 static FAST_RAM_ZERO_INIT int32_t crashRecoveryAngleDeciDegrees;
 362 static FAST_RAM_ZERO_INIT float crashRecoveryRate;
 363 static FAST_RAM_ZERO_INIT float crashDtermThreshold;
 364 static FAST_RAM_ZERO_INIT float crashGyroThreshold;
 365 static FAST_RAM_ZERO_INIT float crashSetpointThreshold;
 366 static FAST_RAM_ZERO_INIT float crashLimitYaw;
 367 static FAST_RAM_ZERO_INIT float itermLimit;
 368 #if defined(USE_THROTTLE_BOOST)
 369 FAST_RAM_ZERO_INIT float throttleBoost;
 370 pt1Filter_t throttleLpf;
 371 #endif
 372 static FAST_RAM_ZERO_INIT bool itermRotation;
 373
 374 #if defined(USE_SMART_FEEDFORWARD)
 375 static FAST_RAM_ZERO_INIT bool smartFeedforward;
 376 #endif
 377 #if defined(USE_ABSOLUTE_CONTROL)
 378 static FAST_RAM_ZERO_INIT float axisError[XYZ_AXIS_COUNT];
 379 static FAST_RAM_ZERO_INIT float acGain;
 380 static FAST_RAM_ZERO_INIT float acLimit;
 381 static FAST_RAM_ZERO_INIT float acErrorLimit;
 382 #endif
 383
 384 void pidResetITerm(void)
 385 {
 386     for (int axis = 0; axis < 3; axis++) {
 387         pidData[axis].I = 0.0f;
 388 #if defined(USE_ABSOLUTE_CONTROL)
 389         axisError[axis] = 0.0f;
 390 #endif
 391     }
 392 }
 393
 394 #ifdef USE_ACRO_TRAINER
 395 static FAST_RAM_ZERO_INIT float acroTrainerAngleLimit;
 396 static FAST_RAM_ZERO_INIT float acroTrainerLookaheadTime;
 397 static FAST_RAM_ZERO_INIT uint8_t acroTrainerDebugAxis;
 398 static FAST_RAM_ZERO_INIT bool acroTrainerActive;
 399 static FAST_RAM_ZERO_INIT int acroTrainerAxisState[2];  // only need roll and pitch
 400 static FAST_RAM_ZERO_INIT float acroTrainerGain;
 401 #endif // USE_ACRO_TRAINER
 402
 403 void pidInitConfig(const pidProfile_t *pidProfile)
 404 {
 405     for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 406         pidCoefficient[axis].Kp = PTERM_SCALE * pidProfile->pid[axis].P;
 407         pidCoefficient[axis].Ki = ITERM_SCALE * pidProfile->pid[axis].I;
 408         pidCoefficient[axis].Kd = DTERM_SCALE * pidProfile->pid[axis].D;
 409     }
 410
 411     dtermSetpointWeight = pidProfile->dtermSetpointWeight / 100.0f;
 412     if (pidProfile->setpointRelaxRatio == 0) {
 413         relaxFactor = 0;
 414     } else {
 415         relaxFactor = 100.0f / pidProfile->setpointRelaxRatio;
 416     }
 417     levelGain = pidProfile->pid[PID_LEVEL].P / 10.0f;
 418     horizonGain = pidProfile->pid[PID_LEVEL].I / 10.0f;
 419     horizonTransition = (float)pidProfile->pid[PID_LEVEL].D;
 420     horizonTiltExpertMode = pidProfile->horizon_tilt_expert_mode;
 421     horizonCutoffDegrees = (175 - pidProfile->horizon_tilt_effect) * 1.8f;
 422     horizonFactorRatio = (100 - pidProfile->horizon_tilt_effect) * 0.01f;
 423     maxVelocity[FD_ROLL] = maxVelocity[FD_PITCH] = pidProfile->rateAccelLimit * 100 * dT;
 424     maxVelocity[FD_YAW] = pidProfile->yawRateAccelLimit * 100 * dT;
 425     const float ITermWindupPoint = (float)pidProfile->itermWindupPointPercent / 100.0f;
 426     ITermWindupPointInv = 1.0f / (1.0f - ITermWindupPoint);
 427     crashTimeLimitUs = pidProfile->crash_time * 1000;
 428     crashTimeDelayUs = pidProfile->crash_delay * 1000;
 429     crashRecoveryAngleDeciDegrees = pidProfile->crash_recovery_angle * 10;
 430     crashRecoveryRate = pidProfile->crash_recovery_rate;
 431     crashGyroThreshold = pidProfile->crash_gthreshold;
 432     crashDtermThreshold = pidProfile->crash_dthreshold;
 433     crashSetpointThreshold = pidProfile->crash_setpoint_threshold;
 434     crashLimitYaw = pidProfile->crash_limit_yaw;
 435     itermLimit = pidProfile->itermLimit;
 436 #if defined(USE_THROTTLE_BOOST)
 437     throttleBoost = pidProfile->throttle_boost * 0.1f;
 438 #endif
 439     itermRotation = pidProfile->iterm_rotation;
 440 #if defined(USE_SMART_FEEDFORWARD)
 441     smartFeedforward = pidProfile->smart_feedforward;
 442 #endif
 443 #if defined(USE_ITERM_RELAX)
 444     itermRelax = pidProfile->iterm_relax;
 445     itermRelaxType = pidProfile->iterm_relax_type;
 446     itermRelaxCutoff = pidProfile->iterm_relax_cutoff;
 447 #endif
 448
 449 #ifdef USE_ACRO_TRAINER
 450     acroTrainerAngleLimit = pidProfile->acro_trainer_angle_limit;
 451     acroTrainerLookaheadTime = (float)pidProfile->acro_trainer_lookahead_ms / 1000.0f;
 452     acroTrainerDebugAxis = pidProfile->acro_trainer_debug_axis;
 453     acroTrainerGain = (float)pidProfile->acro_trainer_gain / 10.0f;
 454 #endif // USE_ACRO_TRAINER
 455
 456 #if defined(USE_ABSOLUTE_CONTROL)
 457     acGain = (float)pidProfile->abs_control_gain;
 458     acLimit = (float)pidProfile->abs_control_limit;
 459     acErrorLimit = (float)pidProfile->abs_control_error_limit;
 460 #endif
 461 }
 462
 463 void pidInit(const pidProfile_t *pidProfile)
 464 {
 465     pidSetTargetLooptime(gyro.targetLooptime * pidConfig()->pid_process_denom); // Initialize pid looptime
 466     pidInitFilters(pidProfile);
 467     pidInitConfig(pidProfile);
 468 }
 469
 470 #ifdef USE_ACRO_TRAINER
 471 void pidAcroTrainerInit(void)
 472 {
 473     acroTrainerAxisState[FD_ROLL] = 0;
 474     acroTrainerAxisState[FD_PITCH] = 0;
 475 }
 476 #endif // USE_ACRO_TRAINER
 477
 478 void pidCopyProfile(uint8_t dstPidProfileIndex, uint8_t srcPidProfileIndex)
 479 {
 480     if ((dstPidProfileIndex < MAX_PROFILE_COUNT-1 && srcPidProfileIndex < MAX_PROFILE_COUNT-1)
 481         && dstPidProfileIndex != srcPidProfileIndex
 482     ) {
 483         memcpy(pidProfilesMutable(dstPidProfileIndex), pidProfilesMutable(srcPidProfileIndex), sizeof(pidProfile_t));
 484     }
 485 }
 486
 487 // calculates strength of horizon leveling; 0 = none, 1.0 = most leveling
 488 static float calcHorizonLevelStrength(void)
 489 {
 490     // start with 1.0 at center stick, 0.0 at max stick deflection:
 491     float horizonLevelStrength = 1.0f - MAX(getRcDeflectionAbs(FD_ROLL), getRcDeflectionAbs(FD_PITCH));
 492
 493     // 0 at level, 90 at vertical, 180 at inverted (degrees):
 494     const float currentInclination = MAX(ABS(attitude.values.roll), ABS(attitude.values.pitch)) / 10.0f;
 495
 496     // horizonTiltExpertMode:  0 = leveling always active when sticks centered,
 497     //                         1 = leveling can be totally off when inverted
 498     if (horizonTiltExpertMode) {
 499         if (horizonTransition > 0 && horizonCutoffDegrees > 0) {
 500                     // if d_level > 0 and horizonTiltEffect < 175
 501             // horizonCutoffDegrees: 0 to 125 => 270 to 90 (represents where leveling goes to zero)
 502             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 503             //  for larger inclinations; 0.0 at horizonCutoffDegrees value:
 504             const float inclinationLevelRatio = constrainf((horizonCutoffDegrees-currentInclination) / horizonCutoffDegrees, 0, 1);
 505             // apply configured horizon sensitivity:
 506                 // when stick is near center (horizonLevelStrength ~= 1.0)
 507                 //  H_sensitivity value has little effect,
 508                 // when stick is deflected (horizonLevelStrength near 0.0)
 509                 //  H_sensitivity value has more effect:
 510             horizonLevelStrength = (horizonLevelStrength - 1) * 100 / horizonTransition + 1;
 511             // apply inclination ratio, which may lower leveling
 512             //  to zero regardless of stick position:
 513             horizonLevelStrength *= inclinationLevelRatio;
 514         } else  { // d_level=0 or horizon_tilt_effect>=175 means no leveling
 515           horizonLevelStrength = 0;
 516         }
 517     } else { // horizon_tilt_expert_mode = 0 (leveling always active when sticks centered)
 518         float sensitFact;
 519         if (horizonFactorRatio < 1.01f) { // if horizonTiltEffect > 0
 520             // horizonFactorRatio: 1.0 to 0.0 (larger means more leveling)
 521             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 522             //  for larger inclinations, goes to 1.0 at inclination==level:
 523             const float inclinationLevelRatio = (180-currentInclination)/180 * (1.0f-horizonFactorRatio) + horizonFactorRatio;
 524             // apply ratio to configured horizon sensitivity:
 525             sensitFact = horizonTransition * inclinationLevelRatio;
 526         } else { // horizonTiltEffect=0 for "old" functionality
 527             sensitFact = horizonTransition;
 528         }
 529
 530         if (sensitFact <= 0) {           // zero means no leveling
 531             horizonLevelStrength = 0;
 532         } else {
 533             // when stick is near center (horizonLevelStrength ~= 1.0)
 534             //  sensitFact value has little effect,
 535             // when stick is deflected (horizonLevelStrength near 0.0)
 536             //  sensitFact value has more effect:
 537             horizonLevelStrength = ((horizonLevelStrength - 1) * (100 / sensitFact)) + 1;
 538         }
 539     }
 540     return constrainf(horizonLevelStrength, 0, 1);
 541 }
 542
 543 static float pidLevel(int axis, const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, float currentPidSetpoint) {
 544     // calculate error angle and limit the angle to the max inclination
 545     // rcDeflection is in range [-1.0, 1.0]
 546     float angle = pidProfile->levelAngleLimit * getRcDeflection(axis);
 547 #ifdef USE_GPS_RESCUE
 548     angle += gpsRescueAngle[axis] / 100; // ANGLE IS IN CENTIDEGREES
 549 #endif
 550     angle = constrainf(angle, -pidProfile->levelAngleLimit, pidProfile->levelAngleLimit);
 551     const float errorAngle = angle - ((attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f);
 552     if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) {
 553         // ANGLE mode - control is angle based
 554         currentPidSetpoint = errorAngle * levelGain;
 555     } else {
 556         // HORIZON mode - mix of ANGLE and ACRO modes
 557         // mix in errorAngle to currentPidSetpoint to add a little auto-level feel
 558         const float horizonLevelStrength = calcHorizonLevelStrength();
 559         currentPidSetpoint = currentPidSetpoint + (errorAngle * horizonGain * horizonLevelStrength);
 560     }
 561     return currentPidSetpoint;
 562 }
 563
 564 static float accelerationLimit(int axis, float currentPidSetpoint)
 565 {
 566     static float previousSetpoint[3];
 567     const float currentVelocity = currentPidSetpoint - previousSetpoint[axis];
 568
 569     if (ABS(currentVelocity) > maxVelocity[axis]) {
 570         currentPidSetpoint = (currentVelocity > 0) ? previousSetpoint[axis] + maxVelocity[axis] : previousSetpoint[axis] - maxVelocity[axis];
 571     }
 572
 573     previousSetpoint[axis] = currentPidSetpoint;
 574     return currentPidSetpoint;
 575 }
 576
 577 static timeUs_t crashDetectedAtUs;
 578
 579 static void handleCrashRecovery(
 580     const pidCrashRecovery_e crash_recovery, const rollAndPitchTrims_t *angleTrim,
 581     const int axis, const timeUs_t currentTimeUs, const float gyroRate, float *currentPidSetpoint, float *errorRate)
 582 {
 583     if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeDelayUs) {
 584         if (crash_recovery == PID_CRASH_RECOVERY_BEEP) {
 585             BEEP_ON;
 586         }
 587         if (axis == FD_YAW) {
 588             *errorRate = constrainf(*errorRate, -crashLimitYaw, crashLimitYaw);
 589         } else {
 590             // on roll and pitch axes calculate currentPidSetpoint and errorRate to level the aircraft to recover from crash
 591             if (sensors(SENSOR_ACC)) {
 592                 // errorAngle is deviation from horizontal
 593                 const float errorAngle =  -(attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 594                 *currentPidSetpoint = errorAngle * levelGain;
 595                 *errorRate = *currentPidSetpoint - gyroRate;
 596             }
 597         }
 598         // reset ITerm, since accumulated error before crash is now meaningless
 599         // and ITerm windup during crash recovery can be extreme, especially on yaw axis
 600         pidData[axis].I = 0.0f;
 601         if (cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeLimitUs
 602             || (getMotorMixRange() < 1.0f
 603                    && ABS(gyro.gyroADCf[FD_ROLL]) < crashRecoveryRate
 604                    && ABS(gyro.gyroADCf[FD_PITCH]) < crashRecoveryRate
 605                    && ABS(gyro.gyroADCf[FD_YAW]) < crashRecoveryRate)) {
 606             if (sensors(SENSOR_ACC)) {
 607                 // check aircraft nearly level
 608                 if (ABS(attitude.raw[FD_ROLL] - angleTrim->raw[FD_ROLL]) < crashRecoveryAngleDeciDegrees
 609                    && ABS(attitude.raw[FD_PITCH] - angleTrim->raw[FD_PITCH]) < crashRecoveryAngleDeciDegrees) {
 610                     inCrashRecoveryMode = false;
 611                     BEEP_OFF;
 612                 }
 613             } else {
 614                 inCrashRecoveryMode = false;
 615                 BEEP_OFF;
 616             }
 617         }
 618     }
 619 }
 620
 621 static void detectAndSetCrashRecovery(
 622     const pidCrashRecovery_e crash_recovery, const int axis,
 623     const timeUs_t currentTimeUs, const float delta, const float errorRate)
 624 {
 625     // if crash recovery is on and accelerometer enabled and there is no gyro overflow, then check for a crash
 626     // no point in trying to recover if the crash is so severe that the gyro overflows
 627     if ((crash_recovery || FLIGHT_MODE(GPS_RESCUE_MODE)) && !gyroOverflowDetected()) {
 628         if (ARMING_FLAG(ARMED)) {
 629             if (getMotorMixRange() >= 1.0f && !inCrashRecoveryMode
 630                 && ABS(delta) > crashDtermThreshold
 631                 && ABS(errorRate) > crashGyroThreshold
 632                 && ABS(getSetpointRate(axis)) < crashSetpointThreshold) {
 633                 inCrashRecoveryMode = true;
 634                 crashDetectedAtUs = currentTimeUs;
 635             }
 636             if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) < crashTimeDelayUs && (ABS(errorRate) < crashGyroThreshold
 637                 || ABS(getSetpointRate(axis)) > crashSetpointThreshold)) {
 638                 inCrashRecoveryMode = false;
 639                 BEEP_OFF;
 640             }
 641         } else if (inCrashRecoveryMode) {
 642             inCrashRecoveryMode = false;
 643             BEEP_OFF;
 644         }
 645     }
 646 }
 647
 648 static void rotateVector(float v[XYZ_AXIS_COUNT], float rotation[XYZ_AXIS_COUNT])
 649 {
 650     // rotate v around rotation vector rotation
 651     // rotation in radians, all elements must be small
 652     for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 653         int i_1 = (i + 1) % 3;
 654         int i_2 = (i + 2) % 3;
 655         float newV = v[i_1] + v[i_2] * rotation[i];
 656         v[i_2] -= v[i_1] * rotation[i];
 657         v[i_1] = newV;
 658     }
 659 }
 660
 661 static void rotateITermAndAxisError()
 662 {
 663     if (itermRotation
 664 #if defined(USE_ABSOLUTE_CONTROL)
 665         || acGain > 0
 666 #endif
 667         ) {
 668         const float gyroToAngle = dT * RAD;
 669         float rotationRads[3];
 670         for (int i = FD_ROLL; i <= FD_YAW; i++) {
 671             rotationRads[i] = gyro.gyroADCf[i] * gyroToAngle;
 672         }
 673 #if defined(USE_ABSOLUTE_CONTROL)
 674         if (acGain > 0) {
 675             rotateVector(axisError, rotationRads);
 676         }
 677 #endif
 678         if (itermRotation) {
 679             float v[3];
 680             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 681                 v[i] = pidData[i].I;
 682             }
 683             rotateVector(v, rotationRads );
 684             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 685                 pidData[i].I = v[i];
 686             }
 687         }
 688     }
 689 }
 690
 691 #ifdef USE_ACRO_TRAINER
 692
 693 int acroTrainerSign(float x)
 694 {
 695     return x > 0 ? 1 : -1;
 696 }
 697
 698 // Acro Trainer - Manipulate the setPoint to limit axis angle while in acro mode
 699 // There are three states:
 700 // 1. Current angle has exceeded limit
 701 //    Apply correction to return to limit (similar to pidLevel)
 702 // 2. Future overflow has been projected based on current angle and gyro rate
 703 //    Manage the setPoint to control the gyro rate as the actual angle  approaches the limit (try to prevent overshoot)
 704 // 3. If no potential overflow is detected, then return the original setPoint
 705
 706 // Use the FAST_CODE_NOINLINE directive to avoid this code from being inlined into ITCM RAM. We accept the
 707 // performance decrease when Acro Trainer mode is active under the assumption that user is unlikely to be
 708 // expecting ultimate flight performance at very high loop rates when in this mode.
 709 static FAST_CODE_NOINLINE float applyAcroTrainer(int axis, const rollAndPitchTrims_t *angleTrim, float setPoint)
 710 {
 711     float ret = setPoint;
 712
 713     if (!FLIGHT_MODE(ANGLE_MODE) && !FLIGHT_MODE(HORIZON_MODE) && !FLIGHT_MODE(GPS_RESCUE_MODE)) {
 714         bool resetIterm = false;
 715         float projectedAngle = 0;
 716         const int setpointSign = acroTrainerSign(setPoint);
 717         const float currentAngle = (attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 718         const int angleSign = acroTrainerSign(currentAngle);
 719
 720         if ((acroTrainerAxisState[axis] != 0) && (acroTrainerAxisState[axis] != setpointSign)) {  // stick has reversed - stop limiting
 721             acroTrainerAxisState[axis] = 0;
 722         }
 723
 724         // Limit and correct the angle when it exceeds the limit
 725         if ((fabsf(currentAngle) > acroTrainerAngleLimit) && (acroTrainerAxisState[axis] == 0)) {
 726             if (angleSign == setpointSign) {
 727                 acroTrainerAxisState[axis] = angleSign;
 728                 resetIterm = true;
 729             }
 730         }
 731
 732         if (acroTrainerAxisState[axis] != 0) {
 733             ret = constrainf(((acroTrainerAngleLimit * angleSign) - currentAngle) * acroTrainerGain, -ACRO_TRAINER_SETPOINT_LIMIT, ACRO_TRAINER_SETPOINT_LIMIT);
 734         } else {
 735
 736         // Not currently over the limit so project the angle based on current angle and
 737         // gyro angular rate using a sliding window based on gyro rate (faster rotation means larger window.
 738         // If the projected angle exceeds the limit then apply limiting to minimize overshoot.
 739             // Calculate the lookahead window by scaling proportionally with gyro rate from 0-500dps
 740             float checkInterval = constrainf(fabsf(gyro.gyroADCf[axis]) / ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT, 0.0f, 1.0f) * acroTrainerLookaheadTime;
 741             projectedAngle = (gyro.gyroADCf[axis] * checkInterval) + currentAngle;
 742             const int projectedAngleSign = acroTrainerSign(projectedAngle);
 743             if ((fabsf(projectedAngle) > acroTrainerAngleLimit) && (projectedAngleSign == setpointSign)) {
 744                 ret = ((acroTrainerAngleLimit * projectedAngleSign) - projectedAngle) * acroTrainerGain;
 745                 resetIterm = true;
 746             }
 747         }
 748
 749         if (resetIterm) {
 750             pidData[axis].I = 0;
 751         }
 752
 753         if (axis == acroTrainerDebugAxis) {
 754             DEBUG_SET(DEBUG_ACRO_TRAINER, 0, lrintf(currentAngle * 10.0f));
 755             DEBUG_SET(DEBUG_ACRO_TRAINER, 1, acroTrainerAxisState[axis]);
 756             DEBUG_SET(DEBUG_ACRO_TRAINER, 2, lrintf(ret));
 757             DEBUG_SET(DEBUG_ACRO_TRAINER, 3, lrintf(projectedAngle * 10.0f));
 758         }
 759     }
 760
 761     return ret;
 762 }
 763 #endif // USE_ACRO_TRAINER
 764
 765 // Betaflight pid controller, which will be maintained in the future with additional features specialised for current (mini) multirotor usage.
 766 // Based on 2DOF reference design (matlab)
 767 void FAST_CODE pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, timeUs_t currentTimeUs)
 768 {
 769     static float previousGyroRateDterm[2];
 770     static float previousPidSetpoint[2];
 771
 772     const float tpaFactor = getThrottlePIDAttenuation();
 773     const float motorMixRange = getMotorMixRange();
 774
 775 #ifdef USE_YAW_SPIN_RECOVERY
 776     const bool yawSpinActive = gyroYawSpinDetected();
 777 #endif
 778
 779     // Dynamic i component,
 780     // gradually scale back integration when above windup point
 781     const float dynCi = MIN((1.0f - motorMixRange) * ITermWindupPointInv, 1.0f) * dT * itermAccelerator;
 782
 783     // Dynamic d component, enable 2-DOF PID controller only for rate mode
 784     const float dynCd = flightModeFlags ? 0.0f : dtermSetpointWeight;
 785
 786     // Precalculate gyro deta for D-term here, this allows loop unrolling
 787     float gyroRateDterm[2];
 788     for (int axis = FD_ROLL; axis < FD_YAW; ++axis) {
 789         gyroRateDterm[axis] = dtermNotchApplyFn((filter_t *) &dtermNotch[axis], gyro.gyroADCf[axis]);
 790         gyroRateDterm[axis] = dtermLowpassApplyFn((filter_t *) &dtermLowpass[axis], gyroRateDterm[axis]);
 791         gyroRateDterm[axis] = dtermLowpass2ApplyFn((filter_t *) &dtermLowpass2[axis], gyroRateDterm[axis]);
 792     }
 793
 794     rotateITermAndAxisError();
 795
 796     // ----------PID controller----------
 797     for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 798         float currentPidSetpoint = getSetpointRate(axis);
 799         if (maxVelocity[axis]) {
 800             currentPidSetpoint = accelerationLimit(axis, currentPidSetpoint);
 801         }
 802         // Yaw control is GYRO based, direct sticks control is applied to rate PID
 803         if ((FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) && axis != YAW) {
 804             currentPidSetpoint = pidLevel(axis, pidProfile, angleTrim, currentPidSetpoint);
 805         }
 806
 807 #ifdef USE_ACRO_TRAINER
 808         if ((axis != FD_YAW) && acroTrainerActive && !inCrashRecoveryMode) {
 809             currentPidSetpoint = applyAcroTrainer(axis, angleTrim, currentPidSetpoint);
 810         }
 811 #endif // USE_ACRO_TRAINER
 812
 813         // Handle yaw spin recovery - zero the setpoint on yaw to aid in recovery
 814         // It's not necessary to zero the set points for R/P because the PIDs will be zeroed below
 815 #ifdef USE_YAW_SPIN_RECOVERY
 816         if ((axis == FD_YAW) && yawSpinActive) {
 817             currentPidSetpoint = 0.0f;
 818         }
 819 #endif // USE_YAW_SPIN_RECOVERY
 820
 821         // -----calculate error rate
 822         const float gyroRate = gyro.gyroADCf[axis]; // Process variable from gyro output in deg/sec
 823
 824 #ifdef USE_ABSOLUTE_CONTROL
 825         float acCorrection = 0;
 826         float acErrorRate;
 827 #endif
 828         float itermErrorRate = 0.0f;
 829
 830 #if defined(USE_ITERM_RELAX)
 831         if (itermRelax && (axis < FD_YAW || itermRelax == ITERM_RELAX_RPY )) {
 832             const float setpointLpf = pt1FilterApply(&windupLpf[axis], currentPidSetpoint);
 833             const float setpointHpf = fabsf(currentPidSetpoint - setpointLpf);
 834             const float itermRelaxFactor = 1 - setpointHpf / 30.0f;
 835             if (itermRelaxType == ITERM_RELAX_SETPOINT && setpointHpf < 30) {
 836                 itermErrorRate = itermRelaxFactor * (currentPidSetpoint - gyroRate);
 837             } else if (itermRelaxType == ITERM_RELAX_GYRO ) {
 838                 itermErrorRate = fapplyDeadband(setpointLpf - gyroRate, setpointHpf);
 839             }
 840
 841             if (axis == FD_ROLL) {
 842                 DEBUG_SET(DEBUG_ITERM_RELAX, 0, lrintf(setpointHpf));
 843                 DEBUG_SET(DEBUG_ITERM_RELAX, 1, lrintf(itermRelaxFactor * 100.0f));
 844                 DEBUG_SET(DEBUG_ITERM_RELAX, 2, lrintf(itermErrorRate));
 845             }
 846
 847 #if defined(USE_ABSOLUTE_CONTROL)
 848             const float gmaxac = setpointLpf + 2 * setpointHpf;
 849             const float gminac = setpointLpf - 2 * setpointHpf;
 850             if (gyroRate >= gminac && gyroRate <= gmaxac) {
 851                 float acErrorRate1 = gmaxac - gyroRate;
 852                 float acErrorRate2 = gminac - gyroRate;
 853                 if (acErrorRate1 * axisError[axis] < 0) {
 854                     acErrorRate = acErrorRate1;
 855                 } else {
 856                     acErrorRate = acErrorRate2;
 857                 }
 858                 if (fabsf(acErrorRate * dT) > fabsf(axisError[axis]) ) {
 859                     acErrorRate = -axisError[axis] / dT;
 860                 }
 861             } else {
 862                 acErrorRate = (gyroRate > gmaxac ? gmaxac : gminac ) - gyroRate;
 863             }
 864 #endif // USE_ABSOLUTE_CONTROL
 865         } else
 866 #endif // USE_ITERM_RELAX
 867         {
 868             itermErrorRate = currentPidSetpoint - gyroRate;
 869 #if defined(USE_ABSOLUTE_CONTROL)
 870             acErrorRate = itermErrorRate;
 871 #endif // USE_ABSOLUTE_CONTROL
 872         }
 873
 874 #if defined(USE_ABSOLUTE_CONTROL)
 875         if (acGain > 0 && isAirmodeActivated()) {
 876             axisError[axis] = constrainf(axisError[axis] + acErrorRate * dT, -acErrorLimit, acErrorLimit);
 877             acCorrection = constrainf(axisError[axis] * acGain, -acLimit, acLimit);
 878             currentPidSetpoint += acCorrection;
 879             itermErrorRate += acCorrection;
 880             if (axis == FD_ROLL) {
 881                 DEBUG_SET(DEBUG_ITERM_RELAX, 3, lrintf(axisError[axis] * 10));
 882             }
 883         }
 884 #endif
 885
 886         float errorRate = currentPidSetpoint - gyroRate; // r - y
 887         handleCrashRecovery(
 888             pidProfile->crash_recovery, angleTrim, axis, currentTimeUs, gyroRate,
 889             &currentPidSetpoint, &errorRate);
 890
 891         // --------low-level gyro-based PID based on 2DOF PID controller. ----------
 892         // 2-DOF PID controller with optional filter on derivative term.
 893         // b = 1 and only c (dtermSetpointWeight) can be tuned (amount derivative on measurement or error).
 894
 895         // -----calculate P component and add Dynamic Part based on stick input
 896         pidData[axis].P = pidCoefficient[axis].Kp * errorRate * tpaFactor;
 897         if (axis == FD_YAW) {
 898             pidData[axis].P = ptermYawLowpassApplyFn((filter_t *) &ptermYawLowpass, pidData[axis].P);
 899         }
 900
 901         // -----calculate I component
 902
 903         const float ITerm = pidData[axis].I;
 904         const float ITermNew = constrainf(ITerm + pidCoefficient[axis].Ki * itermErrorRate * dynCi, -itermLimit, itermLimit);
 905         const bool outputSaturated = mixerIsOutputSaturated(axis, errorRate);
 906         if (outputSaturated == false || ABS(ITermNew) < ABS(ITerm)) {
 907             // Only increase ITerm if output is not saturated
 908             pidData[axis].I = ITermNew;
 909         }
 910
 911         // -----calculate D component
 912         if (axis != FD_YAW) {
 913             // no transition if relaxFactor == 0
 914             float transition = relaxFactor > 0 ? MIN(1.f, getRcDeflectionAbs(axis) * relaxFactor) : 1;
 915
 916             // Divide rate change by dT to get differential (ie dr/dt).
 917             // dT is fixed and calculated from the target PID loop time
 918             // This is done to avoid DTerm spikes that occur with dynamically
 919             // calculated deltaT whenever another task causes the PID
 920             // loop execution to be delayed.
 921             const float delta =
 922                 - (gyroRateDterm[axis] - previousGyroRateDterm[axis]) * pidFrequency;
 923
 924             detectAndSetCrashRecovery(pidProfile->crash_recovery, axis, currentTimeUs, delta, errorRate);
 925
 926             pidData[axis].D = pidCoefficient[axis].Kd * delta * tpaFactor;
 927
 928             float pidSetpointDelta = currentPidSetpoint - previousPidSetpoint[axis];
 929
 930 #ifdef USE_RC_SMOOTHING_FILTER
 931             if (axis == rcSmoothingDebugAxis) {
 932                 DEBUG_SET(DEBUG_RC_SMOOTHING, 1, lrintf(pidSetpointDelta * 100.0f));
 933             }
 934             if ((dynCd != 0) && setpointDerivativeLpfInitialized) {
 935                 switch (rcSmoothingFilterType) {
 936                     case RC_SMOOTHING_DERIVATIVE_PT1:
 937                         pidSetpointDelta = pt1FilterApply(&setpointDerivativePt1[axis], pidSetpointDelta);
 938                         break;
 939                     case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 940                         pidSetpointDelta = biquadFilterApplyDF1(&setpointDerivativeBiquad[axis], pidSetpointDelta);
 941                         break;
 942                 }
 943                 if (axis == rcSmoothingDebugAxis) {
 944                     DEBUG_SET(DEBUG_RC_SMOOTHING, 2, lrintf(pidSetpointDelta * 100.0f));
 945                 }
 946             }
 947 #endif // USE_RC_SMOOTHING_FILTER
 948
 949             const float pidFeedForward =
 950                 pidCoefficient[axis].Kd * dynCd * transition * pidSetpointDelta * tpaFactor * pidFrequency;
 951 #if defined(USE_SMART_FEEDFORWARD)
 952             bool addFeedforward = true;
 953             if (smartFeedforward) {
 954                 if (pidData[axis].P * pidFeedForward > 0) {
 955                     if (ABS(pidFeedForward) > ABS(pidData[axis].P)) {
 956                         pidData[axis].P = 0;
 957                     } else {
 958                         addFeedforward = false;
 959                     }
 960                 }
 961             }
 962             if (addFeedforward)
 963 #endif
 964             {
 965                 pidData[axis].D += pidFeedForward;
 966             }
 967             previousGyroRateDterm[axis] = gyroRateDterm[axis];
 968             previousPidSetpoint[axis] = currentPidSetpoint;
 969
 970 #ifdef USE_YAW_SPIN_RECOVERY
 971             if (yawSpinActive)  {
 972                 // zero PIDs on pitch and roll leaving yaw P to correct spin
 973                 pidData[axis].P = 0;
 974                 pidData[axis].I = 0;
 975                 pidData[axis].D = 0;
 976             }
 977 #endif // USE_YAW_SPIN_RECOVERY
 978         }
 979     }
 980
 981     // calculating the PID sum
 982     pidData[FD_ROLL].Sum = pidData[FD_ROLL].P + pidData[FD_ROLL].I + pidData[FD_ROLL].D;
 983     pidData[FD_PITCH].Sum = pidData[FD_PITCH].P + pidData[FD_PITCH].I + pidData[FD_PITCH].D;
 984
 985 #ifdef USE_YAW_SPIN_RECOVERY
 986     if (yawSpinActive) {
 987     // yaw P alone to correct spin
 988         pidData[FD_YAW].I = 0;
 989     }
 990 #endif // USE_YAW_SPIN_RECOVERY
 991
 992     // YAW has no D
 993     pidData[FD_YAW].Sum = pidData[FD_YAW].P + pidData[FD_YAW].I;
 994
 995     // Disable PID control if at zero throttle or if gyro overflow detected
 996     // This may look very innefficient, but it is done on purpose to always show real CPU usage as in flight
 997     if (!pidStabilisationEnabled || gyroOverflowDetected()) {
 998         for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 999             pidData[axis].P = 0;
1000             pidData[axis].I = 0;
1001             pidData[axis].D = 0;
1002
1003             pidData[axis].Sum = 0;
1004         }
1005     }
1006 }
1007
1008 bool crashRecoveryModeActive(void)
1009 {
1010     return inCrashRecoveryMode;
1011 }
1012
1013 #ifdef USE_ACRO_TRAINER
1014 void pidSetAcroTrainerState(bool newState)
1015 {
1016     if (acroTrainerActive != newState) {
1017         if (newState) {
1018             pidAcroTrainerInit();
1019         }
1020         acroTrainerActive = newState;
1021     }
1022 }
1023 #endif // USE_ACRO_TRAINER