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] =  { 40, 40, 30 },
 104             [PID_PITCH] = { 58, 50, 35 },
 105             [PID_YAW] =   { 70, 45, 20 },
 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,    // filtering ON by default
 119         .dterm_lowpass2_hz = 0,     // second Dterm LPF OFF by default
 120         .dterm_notch_hz = 260,
 121         .dterm_notch_cutoff = 160,
 122         .dterm_filter_type = FILTER_BIQUAD,
 123         .itermWindupPointPercent = 50,
 124         .vbatPidCompensation = 0,
 125         .pidAtMinThrottle = PID_STABILISATION_ON,
 126         .levelAngleLimit = 55,
 127         .setpointRelaxRatio = 100,
 128         .dtermSetpointWeight = 0,
 129         .yawRateAccelLimit = 100,
 130         .rateAccelLimit = 0,
 131         .itermThrottleThreshold = 350,
 132         .itermAcceleratorGain = 1000,
 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 = 0,
 146         .throttle_boost_cutoff = 15,
 147         .iterm_rotation = false,
 148         .smart_feedforward = false,
 149         .iterm_relax = ITERM_RELAX_OFF,
 150         .iterm_relax_cutoff_low = 3,
 151         .iterm_relax_cutoff_high = 30,
 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][2];
 210 static FAST_RAM_ZERO_INIT uint8_t itermRelax;
 211 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoffLow;
 212 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoffHigh;
 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     pt1FilterInit(&throttleLpf, pt1FilterGain(pidProfile->throttle_boost_cutoff, dT));
 298 #if defined(USE_ITERM_RELAX)
 299     if (itermRelax) {
 300         for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 301             pt1FilterInit(&windupLpf[i][0], pt1FilterGain(itermRelaxCutoffLow, dT));
 302             pt1FilterInit(&windupLpf[i][1], pt1FilterGain(itermRelaxCutoffHigh, dT));
 303         }
 304     }
 305 #endif
 306 }
 307
 308 #ifdef USE_RC_SMOOTHING_FILTER
 309 void pidInitSetpointDerivativeLpf(uint16_t filterCutoff, uint8_t debugAxis, uint8_t filterType)
 310 {
 311     rcSmoothingDebugAxis = debugAxis;
 312     rcSmoothingFilterType = filterType;
 313     if ((filterCutoff > 0) && (rcSmoothingFilterType != RC_SMOOTHING_DERIVATIVE_OFF)) {
 314         setpointDerivativeLpfInitialized = true;
 315         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 316             switch (rcSmoothingFilterType) {
 317                 case RC_SMOOTHING_DERIVATIVE_PT1:
 318                     pt1FilterInit(&setpointDerivativePt1[axis], pt1FilterGain(filterCutoff, dT));
 319                     break;
 320                 case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 321                     biquadFilterInitLPF(&setpointDerivativeBiquad[axis], filterCutoff, targetPidLooptime);
 322                     break;
 323             }
 324         }
 325     }
 326 }
 327 #endif // USE_RC_SMOOTHING_FILTER
 328
 329 typedef struct pidCoefficient_s {
 330     float Kp;
 331     float Ki;
 332     float Kd;
 333 } pidCoefficient_t;
 334
 335 static FAST_RAM_ZERO_INIT pidCoefficient_t pidCoefficient[3];
 336 static FAST_RAM_ZERO_INIT float maxVelocity[3];
 337 static FAST_RAM_ZERO_INIT float relaxFactor;
 338 static FAST_RAM_ZERO_INIT float dtermSetpointWeight;
 339 static FAST_RAM_ZERO_INIT float levelGain, horizonGain, horizonTransition, horizonCutoffDegrees, horizonFactorRatio;
 340 static FAST_RAM_ZERO_INIT float ITermWindupPointInv;
 341 static FAST_RAM_ZERO_INIT uint8_t horizonTiltExpertMode;
 342 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeLimitUs;
 343 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeDelayUs;
 344 static FAST_RAM_ZERO_INIT int32_t crashRecoveryAngleDeciDegrees;
 345 static FAST_RAM_ZERO_INIT float crashRecoveryRate;
 346 static FAST_RAM_ZERO_INIT float crashDtermThreshold;
 347 static FAST_RAM_ZERO_INIT float crashGyroThreshold;
 348 static FAST_RAM_ZERO_INIT float crashSetpointThreshold;
 349 static FAST_RAM_ZERO_INIT float crashLimitYaw;
 350 static FAST_RAM_ZERO_INIT float itermLimit;
 351 FAST_RAM_ZERO_INIT float throttleBoost;
 352 pt1Filter_t throttleLpf;
 353 static FAST_RAM_ZERO_INIT bool itermRotation;
 354
 355 #if defined(USE_SMART_FEEDFORWARD)
 356 static FAST_RAM_ZERO_INIT bool smartFeedforward;
 357 #endif
 358 #if defined(USE_ABSOLUTE_CONTROL)
 359 static FAST_RAM_ZERO_INIT float axisError[XYZ_AXIS_COUNT];
 360 static FAST_RAM_ZERO_INIT float acGain;
 361 static FAST_RAM_ZERO_INIT float acLimit;
 362 static FAST_RAM_ZERO_INIT float acErrorLimit;
 363 #endif
 364
 365 void pidResetITerm(void)
 366 {
 367     for (int axis = 0; axis < 3; axis++) {
 368         pidData[axis].I = 0.0f;
 369 #if defined(USE_ABSOLUTE_CONTROL)
 370         axisError[axis] = 0.0f;
 371 #endif
 372     }
 373 }
 374
 375 #ifdef USE_ACRO_TRAINER
 376 static FAST_RAM_ZERO_INIT float acroTrainerAngleLimit;
 377 static FAST_RAM_ZERO_INIT float acroTrainerLookaheadTime;
 378 static FAST_RAM_ZERO_INIT uint8_t acroTrainerDebugAxis;
 379 static FAST_RAM_ZERO_INIT bool acroTrainerActive;
 380 static FAST_RAM_ZERO_INIT int acroTrainerAxisState[2];  // only need roll and pitch
 381 static FAST_RAM_ZERO_INIT float acroTrainerGain;
 382 #endif // USE_ACRO_TRAINER
 383
 384 void pidInitConfig(const pidProfile_t *pidProfile)
 385 {
 386     for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 387         pidCoefficient[axis].Kp = PTERM_SCALE * pidProfile->pid[axis].P;
 388         pidCoefficient[axis].Ki = ITERM_SCALE * pidProfile->pid[axis].I;
 389         pidCoefficient[axis].Kd = DTERM_SCALE * pidProfile->pid[axis].D;
 390     }
 391
 392     dtermSetpointWeight = pidProfile->dtermSetpointWeight / 127.0f;
 393     if (pidProfile->setpointRelaxRatio == 0) {
 394         relaxFactor = 0;
 395     } else {
 396         relaxFactor = 100.0f / pidProfile->setpointRelaxRatio;
 397     }
 398     levelGain = pidProfile->pid[PID_LEVEL].P / 10.0f;
 399     horizonGain = pidProfile->pid[PID_LEVEL].I / 10.0f;
 400     horizonTransition = (float)pidProfile->pid[PID_LEVEL].D;
 401     horizonTiltExpertMode = pidProfile->horizon_tilt_expert_mode;
 402     horizonCutoffDegrees = (175 - pidProfile->horizon_tilt_effect) * 1.8f;
 403     horizonFactorRatio = (100 - pidProfile->horizon_tilt_effect) * 0.01f;
 404     maxVelocity[FD_ROLL] = maxVelocity[FD_PITCH] = pidProfile->rateAccelLimit * 100 * dT;
 405     maxVelocity[FD_YAW] = pidProfile->yawRateAccelLimit * 100 * dT;
 406     const float ITermWindupPoint = (float)pidProfile->itermWindupPointPercent / 100.0f;
 407     ITermWindupPointInv = 1.0f / (1.0f - ITermWindupPoint);
 408     crashTimeLimitUs = pidProfile->crash_time * 1000;
 409     crashTimeDelayUs = pidProfile->crash_delay * 1000;
 410     crashRecoveryAngleDeciDegrees = pidProfile->crash_recovery_angle * 10;
 411     crashRecoveryRate = pidProfile->crash_recovery_rate;
 412     crashGyroThreshold = pidProfile->crash_gthreshold;
 413     crashDtermThreshold = pidProfile->crash_dthreshold;
 414     crashSetpointThreshold = pidProfile->crash_setpoint_threshold;
 415     crashLimitYaw = pidProfile->crash_limit_yaw;
 416     itermLimit = pidProfile->itermLimit;
 417     throttleBoost = pidProfile->throttle_boost * 0.1f;
 418     itermRotation = pidProfile->iterm_rotation;
 419 #if defined(USE_SMART_FEEDFORWARD)
 420     smartFeedforward = pidProfile->smart_feedforward;
 421 #endif
 422 #if defined(USE_ITERM_RELAX)
 423     itermRelax = pidProfile->iterm_relax;
 424     itermRelaxCutoffLow = pidProfile->iterm_relax_cutoff_low;
 425     itermRelaxCutoffHigh = pidProfile->iterm_relax_cutoff_high;
 426 #endif
 427
 428 #ifdef USE_ACRO_TRAINER
 429     acroTrainerAngleLimit = pidProfile->acro_trainer_angle_limit;
 430     acroTrainerLookaheadTime = (float)pidProfile->acro_trainer_lookahead_ms / 1000.0f;
 431     acroTrainerDebugAxis = pidProfile->acro_trainer_debug_axis;
 432     acroTrainerGain = (float)pidProfile->acro_trainer_gain / 10.0f;
 433 #endif // USE_ACRO_TRAINER
 434
 435 #if defined(USE_ABSOLUTE_CONTROL)
 436     acGain = (float)pidProfile->abs_control_gain;
 437     acLimit = (float)pidProfile->abs_control_limit;
 438     acErrorLimit = (float)pidProfile->abs_control_error_limit;
 439 #endif
 440 }
 441
 442 void pidInit(const pidProfile_t *pidProfile)
 443 {
 444     pidSetTargetLooptime(gyro.targetLooptime * pidConfig()->pid_process_denom); // Initialize pid looptime
 445     pidInitFilters(pidProfile);
 446     pidInitConfig(pidProfile);
 447 }
 448
 449 #ifdef USE_ACRO_TRAINER
 450 void pidAcroTrainerInit(void)
 451 {
 452     acroTrainerAxisState[FD_ROLL] = 0;
 453     acroTrainerAxisState[FD_PITCH] = 0;
 454 }
 455 #endif // USE_ACRO_TRAINER
 456
 457 void pidCopyProfile(uint8_t dstPidProfileIndex, uint8_t srcPidProfileIndex)
 458 {
 459     if ((dstPidProfileIndex < MAX_PROFILE_COUNT-1 && srcPidProfileIndex < MAX_PROFILE_COUNT-1)
 460         && dstPidProfileIndex != srcPidProfileIndex
 461     ) {
 462         memcpy(pidProfilesMutable(dstPidProfileIndex), pidProfilesMutable(srcPidProfileIndex), sizeof(pidProfile_t));
 463     }
 464 }
 465
 466 // calculates strength of horizon leveling; 0 = none, 1.0 = most leveling
 467 static float calcHorizonLevelStrength(void)
 468 {
 469     // start with 1.0 at center stick, 0.0 at max stick deflection:
 470     float horizonLevelStrength = 1.0f - MAX(getRcDeflectionAbs(FD_ROLL), getRcDeflectionAbs(FD_PITCH));
 471
 472     // 0 at level, 90 at vertical, 180 at inverted (degrees):
 473     const float currentInclination = MAX(ABS(attitude.values.roll), ABS(attitude.values.pitch)) / 10.0f;
 474
 475     // horizonTiltExpertMode:  0 = leveling always active when sticks centered,
 476     //                         1 = leveling can be totally off when inverted
 477     if (horizonTiltExpertMode) {
 478         if (horizonTransition > 0 && horizonCutoffDegrees > 0) {
 479                     // if d_level > 0 and horizonTiltEffect < 175
 480             // horizonCutoffDegrees: 0 to 125 => 270 to 90 (represents where leveling goes to zero)
 481             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 482             //  for larger inclinations; 0.0 at horizonCutoffDegrees value:
 483             const float inclinationLevelRatio = constrainf((horizonCutoffDegrees-currentInclination) / horizonCutoffDegrees, 0, 1);
 484             // apply configured horizon sensitivity:
 485                 // when stick is near center (horizonLevelStrength ~= 1.0)
 486                 //  H_sensitivity value has little effect,
 487                 // when stick is deflected (horizonLevelStrength near 0.0)
 488                 //  H_sensitivity value has more effect:
 489             horizonLevelStrength = (horizonLevelStrength - 1) * 100 / horizonTransition + 1;
 490             // apply inclination ratio, which may lower leveling
 491             //  to zero regardless of stick position:
 492             horizonLevelStrength *= inclinationLevelRatio;
 493         } else  { // d_level=0 or horizon_tilt_effect>=175 means no leveling
 494           horizonLevelStrength = 0;
 495         }
 496     } else { // horizon_tilt_expert_mode = 0 (leveling always active when sticks centered)
 497         float sensitFact;
 498         if (horizonFactorRatio < 1.01f) { // if horizonTiltEffect > 0
 499             // horizonFactorRatio: 1.0 to 0.0 (larger means more leveling)
 500             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 501             //  for larger inclinations, goes to 1.0 at inclination==level:
 502             const float inclinationLevelRatio = (180-currentInclination)/180 * (1.0f-horizonFactorRatio) + horizonFactorRatio;
 503             // apply ratio to configured horizon sensitivity:
 504             sensitFact = horizonTransition * inclinationLevelRatio;
 505         } else { // horizonTiltEffect=0 for "old" functionality
 506             sensitFact = horizonTransition;
 507         }
 508
 509         if (sensitFact <= 0) {           // zero means no leveling
 510             horizonLevelStrength = 0;
 511         } else {
 512             // when stick is near center (horizonLevelStrength ~= 1.0)
 513             //  sensitFact value has little effect,
 514             // when stick is deflected (horizonLevelStrength near 0.0)
 515             //  sensitFact value has more effect:
 516             horizonLevelStrength = ((horizonLevelStrength - 1) * (100 / sensitFact)) + 1;
 517         }
 518     }
 519     return constrainf(horizonLevelStrength, 0, 1);
 520 }
 521
 522 static float pidLevel(int axis, const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, float currentPidSetpoint) {
 523     // calculate error angle and limit the angle to the max inclination
 524     // rcDeflection is in range [-1.0, 1.0]
 525     float angle = pidProfile->levelAngleLimit * getRcDeflection(axis);
 526 #ifdef USE_GPS_RESCUE
 527     angle += gpsRescueAngle[axis] / 100; // ANGLE IS IN CENTIDEGREES
 528 #endif
 529     angle = constrainf(angle, -pidProfile->levelAngleLimit, pidProfile->levelAngleLimit);
 530     const float errorAngle = angle - ((attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f);
 531     if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) {
 532         // ANGLE mode - control is angle based
 533         currentPidSetpoint = errorAngle * levelGain;
 534     } else {
 535         // HORIZON mode - mix of ANGLE and ACRO modes
 536         // mix in errorAngle to currentPidSetpoint to add a little auto-level feel
 537         const float horizonLevelStrength = calcHorizonLevelStrength();
 538         currentPidSetpoint = currentPidSetpoint + (errorAngle * horizonGain * horizonLevelStrength);
 539     }
 540     return currentPidSetpoint;
 541 }
 542
 543 static float accelerationLimit(int axis, float currentPidSetpoint)
 544 {
 545     static float previousSetpoint[3];
 546     const float currentVelocity = currentPidSetpoint - previousSetpoint[axis];
 547
 548     if (ABS(currentVelocity) > maxVelocity[axis]) {
 549         currentPidSetpoint = (currentVelocity > 0) ? previousSetpoint[axis] + maxVelocity[axis] : previousSetpoint[axis] - maxVelocity[axis];
 550     }
 551
 552     previousSetpoint[axis] = currentPidSetpoint;
 553     return currentPidSetpoint;
 554 }
 555
 556 static timeUs_t crashDetectedAtUs;
 557
 558 static void handleCrashRecovery(
 559     const pidCrashRecovery_e crash_recovery, const rollAndPitchTrims_t *angleTrim,
 560     const int axis, const timeUs_t currentTimeUs, const float gyroRate, float *currentPidSetpoint, float *errorRate)
 561 {
 562     if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeDelayUs) {
 563         if (crash_recovery == PID_CRASH_RECOVERY_BEEP) {
 564             BEEP_ON;
 565         }
 566         if (axis == FD_YAW) {
 567             *errorRate = constrainf(*errorRate, -crashLimitYaw, crashLimitYaw);
 568         } else {
 569             // on roll and pitch axes calculate currentPidSetpoint and errorRate to level the aircraft to recover from crash
 570             if (sensors(SENSOR_ACC)) {
 571                 // errorAngle is deviation from horizontal
 572                 const float errorAngle =  -(attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 573                 *currentPidSetpoint = errorAngle * levelGain;
 574                 *errorRate = *currentPidSetpoint - gyroRate;
 575             }
 576         }
 577         // reset ITerm, since accumulated error before crash is now meaningless
 578         // and ITerm windup during crash recovery can be extreme, especially on yaw axis
 579         pidData[axis].I = 0.0f;
 580         if (cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeLimitUs
 581             || (getMotorMixRange() < 1.0f
 582                    && ABS(gyro.gyroADCf[FD_ROLL]) < crashRecoveryRate
 583                    && ABS(gyro.gyroADCf[FD_PITCH]) < crashRecoveryRate
 584                    && ABS(gyro.gyroADCf[FD_YAW]) < crashRecoveryRate)) {
 585             if (sensors(SENSOR_ACC)) {
 586                 // check aircraft nearly level
 587                 if (ABS(attitude.raw[FD_ROLL] - angleTrim->raw[FD_ROLL]) < crashRecoveryAngleDeciDegrees
 588                    && ABS(attitude.raw[FD_PITCH] - angleTrim->raw[FD_PITCH]) < crashRecoveryAngleDeciDegrees) {
 589                     inCrashRecoveryMode = false;
 590                     BEEP_OFF;
 591                 }
 592             } else {
 593                 inCrashRecoveryMode = false;
 594                 BEEP_OFF;
 595             }
 596         }
 597     }
 598 }
 599
 600 static void detectAndSetCrashRecovery(
 601     const pidCrashRecovery_e crash_recovery, const int axis,
 602     const timeUs_t currentTimeUs, const float delta, const float errorRate)
 603 {
 604     // if crash recovery is on and accelerometer enabled and there is no gyro overflow, then check for a crash
 605     // no point in trying to recover if the crash is so severe that the gyro overflows
 606     if ((crash_recovery || FLIGHT_MODE(GPS_RESCUE_MODE)) && !gyroOverflowDetected()) {
 607         if (ARMING_FLAG(ARMED)) {
 608             if (getMotorMixRange() >= 1.0f && !inCrashRecoveryMode
 609                 && ABS(delta) > crashDtermThreshold
 610                 && ABS(errorRate) > crashGyroThreshold
 611                 && ABS(getSetpointRate(axis)) < crashSetpointThreshold) {
 612                 inCrashRecoveryMode = true;
 613                 crashDetectedAtUs = currentTimeUs;
 614             }
 615             if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) < crashTimeDelayUs && (ABS(errorRate) < crashGyroThreshold
 616                 || ABS(getSetpointRate(axis)) > crashSetpointThreshold)) {
 617                 inCrashRecoveryMode = false;
 618                 BEEP_OFF;
 619             }
 620         } else if (inCrashRecoveryMode) {
 621             inCrashRecoveryMode = false;
 622             BEEP_OFF;
 623         }
 624     }
 625 }
 626
 627 static void rotateVector(float v[XYZ_AXIS_COUNT], float rotation[XYZ_AXIS_COUNT])
 628 {
 629     // rotate v around rotation vector rotation
 630     // rotation in radians, all elements must be small
 631     for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 632         int i_1 = (i + 1) % 3;
 633         int i_2 = (i + 2) % 3;
 634         float newV = v[i_1] + v[i_2] * rotation[i];
 635         v[i_2] -= v[i_1] * rotation[i];
 636         v[i_1] = newV;
 637     }
 638 }
 639
 640 static void rotateITermAndAxisError()
 641 {
 642     if (itermRotation
 643 #if defined(USE_ABSOLUTE_CONTROL)
 644         || acGain > 0
 645 #endif
 646         ) {
 647         const float gyroToAngle = dT * RAD;
 648         float rotationRads[3];
 649         for (int i = FD_ROLL; i <= FD_YAW; i++) {
 650             rotationRads[i] = gyro.gyroADCf[i] * gyroToAngle;
 651         }
 652 #if defined(USE_ABSOLUTE_CONTROL)
 653         if (acGain > 0) {
 654             rotateVector(axisError, rotationRads);
 655         }
 656 #endif
 657         if (itermRotation) {
 658             float v[3];
 659             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 660                 v[i] = pidData[i].I;
 661             }
 662             rotateVector(v, rotationRads );
 663             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 664                 pidData[i].I = v[i];
 665             }
 666         }
 667     }
 668 }
 669
 670 #ifdef USE_ACRO_TRAINER
 671
 672 int acroTrainerSign(float x)
 673 {
 674     return x > 0 ? 1 : -1;
 675 }
 676
 677 // Acro Trainer - Manipulate the setPoint to limit axis angle while in acro mode
 678 // There are three states:
 679 // 1. Current angle has exceeded limit
 680 //    Apply correction to return to limit (similar to pidLevel)
 681 // 2. Future overflow has been projected based on current angle and gyro rate
 682 //    Manage the setPoint to control the gyro rate as the actual angle  approaches the limit (try to prevent overshoot)
 683 // 3. If no potential overflow is detected, then return the original setPoint
 684
 685 // Use the FAST_CODE_NOINLINE directive to avoid this code from being inlined into ITCM RAM. We accept the
 686 // performance decrease when Acro Trainer mode is active under the assumption that user is unlikely to be
 687 // expecting ultimate flight performance at very high loop rates when in this mode.
 688 static FAST_CODE_NOINLINE float applyAcroTrainer(int axis, const rollAndPitchTrims_t *angleTrim, float setPoint)
 689 {
 690     float ret = setPoint;
 691
 692     if (!FLIGHT_MODE(ANGLE_MODE) && !FLIGHT_MODE(HORIZON_MODE) && !FLIGHT_MODE(GPS_RESCUE_MODE)) {
 693         bool resetIterm = false;
 694         float projectedAngle = 0;
 695         const int setpointSign = acroTrainerSign(setPoint);
 696         const float currentAngle = (attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 697         const int angleSign = acroTrainerSign(currentAngle);
 698
 699         if ((acroTrainerAxisState[axis] != 0) && (acroTrainerAxisState[axis] != setpointSign)) {  // stick has reversed - stop limiting
 700             acroTrainerAxisState[axis] = 0;
 701         }
 702
 703         // Limit and correct the angle when it exceeds the limit
 704         if ((fabsf(currentAngle) > acroTrainerAngleLimit) && (acroTrainerAxisState[axis] == 0)) {
 705             if (angleSign == setpointSign) {
 706                 acroTrainerAxisState[axis] = angleSign;
 707                 resetIterm = true;
 708             }
 709         }
 710
 711         if (acroTrainerAxisState[axis] != 0) {
 712             ret = constrainf(((acroTrainerAngleLimit * angleSign) - currentAngle) * acroTrainerGain, -ACRO_TRAINER_SETPOINT_LIMIT, ACRO_TRAINER_SETPOINT_LIMIT);
 713         } else {
 714
 715         // Not currently over the limit so project the angle based on current angle and
 716         // gyro angular rate using a sliding window based on gyro rate (faster rotation means larger window.
 717         // If the projected angle exceeds the limit then apply limiting to minimize overshoot.
 718             // Calculate the lookahead window by scaling proportionally with gyro rate from 0-500dps
 719             float checkInterval = constrainf(fabsf(gyro.gyroADCf[axis]) / ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT, 0.0f, 1.0f) * acroTrainerLookaheadTime;
 720             projectedAngle = (gyro.gyroADCf[axis] * checkInterval) + currentAngle;
 721             const int projectedAngleSign = acroTrainerSign(projectedAngle);
 722             if ((fabsf(projectedAngle) > acroTrainerAngleLimit) && (projectedAngleSign == setpointSign)) {
 723                 ret = ((acroTrainerAngleLimit * projectedAngleSign) - projectedAngle) * acroTrainerGain;
 724                 resetIterm = true;
 725             }
 726         }
 727
 728         if (resetIterm) {
 729             pidData[axis].I = 0;
 730         }
 731
 732         if (axis == acroTrainerDebugAxis) {
 733             DEBUG_SET(DEBUG_ACRO_TRAINER, 0, lrintf(currentAngle * 10.0f));
 734             DEBUG_SET(DEBUG_ACRO_TRAINER, 1, acroTrainerAxisState[axis]);
 735             DEBUG_SET(DEBUG_ACRO_TRAINER, 2, lrintf(ret));
 736             DEBUG_SET(DEBUG_ACRO_TRAINER, 3, lrintf(projectedAngle * 10.0f));
 737         }
 738     }
 739
 740     return ret;
 741 }
 742 #endif // USE_ACRO_TRAINER
 743
 744 // Betaflight pid controller, which will be maintained in the future with additional features specialised for current (mini) multirotor usage.
 745 // Based on 2DOF reference design (matlab)
 746 void FAST_CODE pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, timeUs_t currentTimeUs)
 747 {
 748     static float previousGyroRateDterm[2];
 749     static float previousPidSetpoint[2];
 750
 751     const float tpaFactor = getThrottlePIDAttenuation();
 752     const float motorMixRange = getMotorMixRange();
 753
 754 #ifdef USE_YAW_SPIN_RECOVERY
 755     const bool yawSpinActive = gyroYawSpinDetected();
 756 #endif
 757
 758     // Dynamic i component,
 759     // gradually scale back integration when above windup point
 760     const float dynCi = MIN((1.0f - motorMixRange) * ITermWindupPointInv, 1.0f) * dT * itermAccelerator;
 761
 762     // Dynamic d component, enable 2-DOF PID controller only for rate mode
 763     const float dynCd = flightModeFlags ? 0.0f : dtermSetpointWeight;
 764
 765     // Precalculate gyro deta for D-term here, this allows loop unrolling
 766     float gyroRateDterm[2];
 767     for (int axis = FD_ROLL; axis < FD_YAW; ++axis) {
 768         gyroRateDterm[axis] = dtermNotchApplyFn((filter_t *) &dtermNotch[axis], gyro.gyroADCf[axis]);
 769         gyroRateDterm[axis] = dtermLowpassApplyFn((filter_t *) &dtermLowpass[axis], gyroRateDterm[axis]);
 770         gyroRateDterm[axis] = dtermLowpass2ApplyFn((filter_t *) &dtermLowpass2[axis], gyroRateDterm[axis]);
 771     }
 772
 773     rotateITermAndAxisError();
 774
 775     // ----------PID controller----------
 776     for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 777         float currentPidSetpoint = getSetpointRate(axis);
 778         if (maxVelocity[axis]) {
 779             currentPidSetpoint = accelerationLimit(axis, currentPidSetpoint);
 780         }
 781         // Yaw control is GYRO based, direct sticks control is applied to rate PID
 782         if ((FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) && axis != YAW) {
 783             currentPidSetpoint = pidLevel(axis, pidProfile, angleTrim, currentPidSetpoint);
 784         }
 785
 786 #ifdef USE_ACRO_TRAINER
 787         if ((axis != FD_YAW) && acroTrainerActive && !inCrashRecoveryMode) {
 788             currentPidSetpoint = applyAcroTrainer(axis, angleTrim, currentPidSetpoint);
 789         }
 790 #endif // USE_ACRO_TRAINER
 791
 792         // Handle yaw spin recovery - zero the setpoint on yaw to aid in recovery
 793         // It's not necessary to zero the set points for R/P because the PIDs will be zeroed below
 794 #ifdef USE_YAW_SPIN_RECOVERY
 795         if ((axis == FD_YAW) && yawSpinActive) {
 796             currentPidSetpoint = 0.0f;
 797         }
 798 #endif // USE_YAW_SPIN_RECOVERY
 799
 800 #if defined(USE_ABSOLUTE_CONTROL)
 801         // mix in a correction for accrued attitude error
 802         float acCorrection = 0;
 803         if (acGain > 0) {
 804             acCorrection = constrainf(axisError[axis] * acGain, -acLimit, acLimit);
 805             currentPidSetpoint += acCorrection;
 806         }
 807 #endif
 808
 809         // -----calculate error rate
 810         const float gyroRate = gyro.gyroADCf[axis]; // Process variable from gyro output in deg/sec
 811         float errorRate = currentPidSetpoint - gyroRate; // r - y
 812
 813         handleCrashRecovery(
 814             pidProfile->crash_recovery, angleTrim, axis, currentTimeUs, gyroRate,
 815             &currentPidSetpoint, &errorRate);
 816
 817         // --------low-level gyro-based PID based on 2DOF PID controller. ----------
 818         // 2-DOF PID controller with optional filter on derivative term.
 819         // b = 1 and only c (dtermSetpointWeight) can be tuned (amount derivative on measurement or error).
 820
 821         // -----calculate P component and add Dynamic Part based on stick input
 822         pidData[axis].P = pidCoefficient[axis].Kp * errorRate * tpaFactor;
 823         if (axis == FD_YAW) {
 824             pidData[axis].P = ptermYawLowpassApplyFn((filter_t *) &ptermYawLowpass, pidData[axis].P);
 825         }
 826
 827         // -----calculate I component
 828         float itermErrorRate = 0.0f;
 829 #if defined(USE_ABSOLUTE_CONTROL)
 830         float acErrorRate;
 831 #endif
 832 #if defined(USE_ITERM_RELAX)
 833         if (itermRelax && (axis < FD_YAW || itermRelax == ITERM_RELAX_RPY )) {
 834             float gyroTargetLow = pt1FilterApply(&windupLpf[axis][0], currentPidSetpoint);
 835             float gyroTargetHigh = pt1FilterApply(&windupLpf[axis][1], currentPidSetpoint);
 836 #if defined(USE_ABSOLUTE_CONTROL)
 837             gyroTargetLow += acCorrection;
 838             gyroTargetHigh += acCorrection;
 839 #endif
 840             if (axis < FD_YAW) {
 841                 int itemOffset = (axis << 1);
 842                 DEBUG_SET(DEBUG_ITERM_RELAX, itemOffset++, gyroTargetHigh);
 843                 DEBUG_SET(DEBUG_ITERM_RELAX, itemOffset, gyroTargetLow);
 844             }
 845             const float gmax = MAX(gyroTargetHigh, gyroTargetLow);
 846             const float gmin = MIN(gyroTargetHigh, gyroTargetLow);
 847             if (gyroRate < gmin || gyroRate > gmax) {
 848                 itermErrorRate = (gyroRate > gmax ? gmax : gmin ) - gyroRate;
 849             }
 850 #if defined(USE_ABSOLUTE_CONTROL)
 851             else {
 852                 itermErrorRate = acCorrection;
 853             }
 854             acErrorRate = itermErrorRate - acCorrection;
 855 #endif
 856         } else
 857 #endif // USE_ITERM_RELAX
 858         {
 859             itermErrorRate = errorRate;
 860 #if defined(USE_ABSOLUTE_CONTROL)
 861             acErrorRate = errorRate;
 862 #endif
 863         }
 864
 865 #if defined(USE_ABSOLUTE_CONTROL)
 866         if (acGain > 0) {
 867             axisError[axis] = constrainf(axisError[axis] + acErrorRate * dT, -acErrorLimit, acErrorLimit);
 868         }
 869 #endif
 870
 871         const float ITerm = pidData[axis].I;
 872         const float ITermNew = constrainf(ITerm + pidCoefficient[axis].Ki * itermErrorRate * dynCi, -itermLimit, itermLimit);
 873         const bool outputSaturated = mixerIsOutputSaturated(axis, errorRate);
 874         if (outputSaturated == false || ABS(ITermNew) < ABS(ITerm)) {
 875             // Only increase ITerm if output is not saturated
 876             pidData[axis].I = ITermNew;
 877         }
 878
 879         // -----calculate D component
 880         if (axis != FD_YAW) {
 881             // no transition if relaxFactor == 0
 882             float transition = relaxFactor > 0 ? MIN(1.f, getRcDeflectionAbs(axis) * relaxFactor) : 1;
 883
 884             // Divide rate change by dT to get differential (ie dr/dt).
 885             // dT is fixed and calculated from the target PID loop time
 886             // This is done to avoid DTerm spikes that occur with dynamically
 887             // calculated deltaT whenever another task causes the PID
 888             // loop execution to be delayed.
 889             const float delta =
 890                 - (gyroRateDterm[axis] - previousGyroRateDterm[axis]) * pidFrequency;
 891
 892             detectAndSetCrashRecovery(pidProfile->crash_recovery, axis, currentTimeUs, delta, errorRate);
 893
 894             pidData[axis].D = pidCoefficient[axis].Kd * delta * tpaFactor;
 895
 896             float pidSetpointDelta = currentPidSetpoint - previousPidSetpoint[axis];
 897
 898 #ifdef USE_RC_SMOOTHING_FILTER
 899             if (axis == rcSmoothingDebugAxis) {
 900                 DEBUG_SET(DEBUG_RC_SMOOTHING, 1, lrintf(pidSetpointDelta * 100.0f));
 901             }
 902             if ((dynCd != 0) && setpointDerivativeLpfInitialized) {
 903                 switch (rcSmoothingFilterType) {
 904                     case RC_SMOOTHING_DERIVATIVE_PT1:
 905                         pidSetpointDelta = pt1FilterApply(&setpointDerivativePt1[axis], pidSetpointDelta);
 906                         break;
 907                     case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 908                         pidSetpointDelta = biquadFilterApply(&setpointDerivativeBiquad[axis], pidSetpointDelta);
 909                         break;
 910                 }
 911                 if (axis == rcSmoothingDebugAxis) {
 912                     DEBUG_SET(DEBUG_RC_SMOOTHING, 2, lrintf(pidSetpointDelta * 100.0f));
 913                 }
 914             }
 915 #endif // USE_RC_SMOOTHING_FILTER
 916
 917             const float pidFeedForward =
 918                 pidCoefficient[axis].Kd * dynCd * transition * pidSetpointDelta * tpaFactor * pidFrequency;
 919 #if defined(USE_SMART_FEEDFORWARD)
 920             bool addFeedforward = true;
 921             if (smartFeedforward) {
 922                 if (pidData[axis].P * pidFeedForward > 0) {
 923                     if (ABS(pidFeedForward) > ABS(pidData[axis].P)) {
 924                         pidData[axis].P = 0;
 925                     } else {
 926                         addFeedforward = false;
 927                     }
 928                 }
 929             }
 930             if (addFeedforward)
 931 #endif
 932             {
 933                 pidData[axis].D += pidFeedForward;
 934             }
 935             previousGyroRateDterm[axis] = gyroRateDterm[axis];
 936             previousPidSetpoint[axis] = currentPidSetpoint;
 937
 938 #ifdef USE_YAW_SPIN_RECOVERY
 939             if (yawSpinActive)  {
 940                 // zero PIDs on pitch and roll leaving yaw P to correct spin
 941                 pidData[axis].P = 0;
 942                 pidData[axis].I = 0;
 943                 pidData[axis].D = 0;
 944             }
 945 #endif // USE_YAW_SPIN_RECOVERY
 946         }
 947     }
 948
 949     // calculating the PID sum
 950     pidData[FD_ROLL].Sum = pidData[FD_ROLL].P + pidData[FD_ROLL].I + pidData[FD_ROLL].D;
 951     pidData[FD_PITCH].Sum = pidData[FD_PITCH].P + pidData[FD_PITCH].I + pidData[FD_PITCH].D;
 952
 953 #ifdef USE_YAW_SPIN_RECOVERY
 954     if (yawSpinActive) {
 955     // yaw P alone to correct spin
 956         pidData[FD_YAW].I = 0;
 957     }
 958 #endif // USE_YAW_SPIN_RECOVERY
 959
 960     // YAW has no D
 961     pidData[FD_YAW].Sum = pidData[FD_YAW].P + pidData[FD_YAW].I;
 962
 963     // Disable PID control if at zero throttle or if gyro overflow detected
 964     // This may look very innefficient, but it is done on purpose to always show real CPU usage as in flight
 965     if (!pidStabilisationEnabled || gyroOverflowDetected()) {
 966         for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 967             pidData[axis].P = 0;
 968             pidData[axis].I = 0;
 969             pidData[axis].D = 0;
 970
 971             pidData[axis].Sum = 0;
 972         }
 973     }
 974 }
 975
 976 bool crashRecoveryModeActive(void)
 977 {
 978     return inCrashRecoveryMode;
 979 }
 980
 981 #ifdef USE_ACRO_TRAINER
 982 void pidSetAcroTrainerState(bool newState)
 983 {
 984     if (acroTrainerActive != newState) {
 985         if (newState) {
 986             pidAcroTrainerInit();
 987         }
 988         acroTrainerActive = newState;
 989     }
 990 }
 991 #endif // USE_ACRO_TRAINER