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/core.h"
  43 #include "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 const char pidNames[] =
  60     "ROLL;"
  61     "PITCH;"
  62     "YAW;"
  63     "LEVEL;"
  64     "MAG;";
  65
  66 FAST_RAM_ZERO_INIT uint32_t targetPidLooptime;
  67 FAST_RAM_ZERO_INIT pidAxisData_t pidData[XYZ_AXIS_COUNT];
  68
  69 static FAST_RAM_ZERO_INIT bool pidStabilisationEnabled;
  70
  71 static FAST_RAM_ZERO_INIT bool inCrashRecoveryMode = false;
  72
  73 static FAST_RAM_ZERO_INIT float dT;
  74 static FAST_RAM_ZERO_INIT float pidFrequency;
  75
  76 static FAST_RAM_ZERO_INIT uint8_t antiGravityMode;
  77 static FAST_RAM_ZERO_INIT float antiGravityThrottleHpf;
  78 static FAST_RAM_ZERO_INIT uint16_t itermAcceleratorGain;
  79 static FAST_RAM float antiGravityOsdCutoff = 1.0f;
  80 static FAST_RAM_ZERO_INIT bool antiGravityEnabled;
  81
  82 PG_REGISTER_WITH_RESET_TEMPLATE(pidConfig_t, pidConfig, PG_PID_CONFIG, 2);
  83
  84 #ifdef STM32F10X
  85 #define PID_PROCESS_DENOM_DEFAULT       1
  86 #elif defined(USE_GYRO_SPI_MPU6000) || defined(USE_GYRO_SPI_MPU6500)  || defined(USE_GYRO_SPI_ICM20689)
  87 #define PID_PROCESS_DENOM_DEFAULT       4
  88 #else
  89 #define PID_PROCESS_DENOM_DEFAULT       2
  90 #endif
  91
  92 #ifdef USE_RUNAWAY_TAKEOFF
  93 PG_RESET_TEMPLATE(pidConfig_t, pidConfig,
  94     .pid_process_denom = PID_PROCESS_DENOM_DEFAULT,
  95     .runaway_takeoff_prevention = true,
  96     .runaway_takeoff_deactivate_throttle = 25,  // throttle level % needed to accumulate deactivation time
  97     .runaway_takeoff_deactivate_delay = 500     // Accumulated time (in milliseconds) before deactivation in successful takeoff
  98 );
  99 #else
 100 PG_RESET_TEMPLATE(pidConfig_t, pidConfig,
 101     .pid_process_denom = PID_PROCESS_DENOM_DEFAULT
 102 );
 103 #endif
 104
 105 #ifdef USE_ACRO_TRAINER
 106 #define ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT 500.0f  // Max gyro rate for lookahead time scaling
 107 #define ACRO_TRAINER_SETPOINT_LIMIT       1000.0f // Limit the correcting setpoint
 108 #endif // USE_ACRO_TRAINER
 109
 110 #define ANTI_GRAVITY_THROTTLE_FILTER_CUTOFF 15  // The anti gravity throttle highpass filter cutoff
 111
 112 PG_REGISTER_ARRAY_WITH_RESET_FN(pidProfile_t, MAX_PROFILE_COUNT, pidProfiles, PG_PID_PROFILE, 5);
 113
 114 void resetPidProfile(pidProfile_t *pidProfile)
 115 {
 116     RESET_CONFIG(pidProfile_t, pidProfile,
 117         .pid = {
 118             [PID_ROLL] =  { 46, 65, 25, 60 },
 119             [PID_PITCH] = { 50, 75, 27, 60 },
 120             [PID_YAW] =   { 45, 100, 0, 100 },
 121             [PID_LEVEL] = { 50, 50, 75, 0 },
 122             [PID_MAG] =   { 40, 0, 0, 0 },
 123         },
 124         .pidSumLimit = PIDSUM_LIMIT,
 125         .pidSumLimitYaw = PIDSUM_LIMIT_YAW,
 126         .yaw_lowpass_hz = 0,
 127         .dterm_notch_hz = 0,
 128         .dterm_notch_cutoff = 0,
 129         .itermWindupPointPercent = 100,
 130         .vbatPidCompensation = 0,
 131         .pidAtMinThrottle = PID_STABILISATION_ON,
 132         .levelAngleLimit = 55,
 133         .feedForwardTransition = 0,
 134         .yawRateAccelLimit = 0,
 135         .rateAccelLimit = 0,
 136         .itermThrottleThreshold = 250,
 137         .itermAcceleratorGain = 5000,
 138         .crash_time = 500,          // ms
 139         .crash_delay = 0,           // ms
 140         .crash_recovery_angle = 10, // degrees
 141         .crash_recovery_rate = 100, // degrees/second
 142         .crash_dthreshold = 50,     // degrees/second/second
 143         .crash_gthreshold = 400,    // degrees/second
 144         .crash_setpoint_threshold = 350, // degrees/second
 145         .crash_recovery = PID_CRASH_RECOVERY_OFF, // off by default
 146         .horizon_tilt_effect = 75,
 147         .horizon_tilt_expert_mode = false,
 148         .crash_limit_yaw = 200,
 149         .itermLimit = 400,
 150         .throttle_boost = 5,
 151         .throttle_boost_cutoff = 15,
 152         .iterm_rotation = true,
 153         .smart_feedforward = false,
 154         .iterm_relax = ITERM_RELAX_RP,
 155         .iterm_relax_cutoff = 20,
 156         .iterm_relax_type = ITERM_RELAX_SETPOINT,
 157         .acro_trainer_angle_limit = 20,
 158         .acro_trainer_lookahead_ms = 50,
 159         .acro_trainer_debug_axis = FD_ROLL,
 160         .acro_trainer_gain = 75,
 161         .abs_control_gain = 0,
 162         .abs_control_limit = 90,
 163         .abs_control_error_limit = 20,
 164         .antiGravityMode = ANTI_GRAVITY_SMOOTH,
 165         .dyn_lpf_dterm_max_hz = 200,
 166         .dyn_lpf_dterm_idle = 20,
 167         .dterm_lowpass_hz = 100,    // dual PT1 filtering ON by default
 168         .dterm_lowpass2_hz = 200,   // second Dterm LPF ON by default
 169         .dterm_filter_type = FILTER_PT1,
 170         .dterm_filter2_type = FILTER_PT1,
 171     );
 172 #ifdef USE_DYN_LPF
 173     pidProfile->dterm_lowpass_hz = 120;
 174     pidProfile->dterm_lowpass2_hz = 180;
 175     pidProfile->dterm_filter_type = FILTER_BIQUAD;
 176     pidProfile->dterm_filter2_type = FILTER_BIQUAD;
 177 #endif
 178 }
 179
 180 void pgResetFn_pidProfiles(pidProfile_t *pidProfiles)
 181 {
 182     for (int i = 0; i < MAX_PROFILE_COUNT; i++) {
 183         resetPidProfile(&pidProfiles[i]);
 184     }
 185 }
 186
 187 static void pidSetTargetLooptime(uint32_t pidLooptime)
 188 {
 189     targetPidLooptime = pidLooptime;
 190     dT = targetPidLooptime * 1e-6f;
 191     pidFrequency = 1.0f / dT;
 192 }
 193
 194 static FAST_RAM float itermAccelerator = 1.0f;
 195
 196 void pidSetItermAccelerator(float newItermAccelerator)
 197 {
 198     itermAccelerator = newItermAccelerator;
 199 }
 200
 201 bool pidOsdAntiGravityActive(void)
 202 {
 203     return (itermAccelerator > antiGravityOsdCutoff);
 204 }
 205
 206 void pidStabilisationState(pidStabilisationState_e pidControllerState)
 207 {
 208     pidStabilisationEnabled = (pidControllerState == PID_STABILISATION_ON) ? true : false;
 209 }
 210
 211 const angle_index_t rcAliasToAngleIndexMap[] = { AI_ROLL, AI_PITCH };
 212
 213 typedef union dtermLowpass_u {
 214     pt1Filter_t pt1Filter;
 215     biquadFilter_t biquadFilter;
 216 } dtermLowpass_t;
 217
 218 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermNotchApplyFn;
 219 static FAST_RAM_ZERO_INIT biquadFilter_t dtermNotch[XYZ_AXIS_COUNT];
 220 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpassApplyFn;
 221 static FAST_RAM_ZERO_INIT dtermLowpass_t dtermLowpass[XYZ_AXIS_COUNT];
 222 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpass2ApplyFn;
 223 static FAST_RAM_ZERO_INIT dtermLowpass_t dtermLowpass2[XYZ_AXIS_COUNT];
 224 static FAST_RAM_ZERO_INIT filterApplyFnPtr ptermYawLowpassApplyFn;
 225 static FAST_RAM_ZERO_INIT pt1Filter_t ptermYawLowpass;
 226 #if defined(USE_ITERM_RELAX)
 227 static FAST_RAM_ZERO_INIT pt1Filter_t windupLpf[XYZ_AXIS_COUNT];
 228 static FAST_RAM_ZERO_INIT uint8_t itermRelax;
 229 static FAST_RAM_ZERO_INIT uint8_t itermRelaxType;
 230 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoff;
 231 #endif
 232
 233 #ifdef USE_RC_SMOOTHING_FILTER
 234 static FAST_RAM_ZERO_INIT pt1Filter_t setpointDerivativePt1[XYZ_AXIS_COUNT];
 235 static FAST_RAM_ZERO_INIT biquadFilter_t setpointDerivativeBiquad[XYZ_AXIS_COUNT];
 236 static FAST_RAM_ZERO_INIT bool setpointDerivativeLpfInitialized;
 237 static FAST_RAM_ZERO_INIT uint8_t rcSmoothingDebugAxis;
 238 static FAST_RAM_ZERO_INIT uint8_t rcSmoothingFilterType;
 239 #endif // USE_RC_SMOOTHING_FILTER
 240
 241 static FAST_RAM_ZERO_INIT pt1Filter_t antiGravityThrottleLpf;
 242
 243 void pidInitFilters(const pidProfile_t *pidProfile)
 244 {
 245     STATIC_ASSERT(FD_YAW == 2, FD_YAW_incorrect); // ensure yaw axis is 2
 246
 247     if (targetPidLooptime == 0) {
 248         // no looptime set, so set all the filters to null
 249         dtermNotchApplyFn = nullFilterApply;
 250         dtermLowpassApplyFn = nullFilterApply;
 251         ptermYawLowpassApplyFn = nullFilterApply;
 252         return;
 253     }
 254
 255     const uint32_t pidFrequencyNyquist = pidFrequency / 2; // No rounding needed
 256
 257     uint16_t dTermNotchHz;
 258     if (pidProfile->dterm_notch_hz <= pidFrequencyNyquist) {
 259         dTermNotchHz = pidProfile->dterm_notch_hz;
 260     } else {
 261         if (pidProfile->dterm_notch_cutoff < pidFrequencyNyquist) {
 262             dTermNotchHz = pidFrequencyNyquist;
 263         } else {
 264             dTermNotchHz = 0;
 265         }
 266     }
 267
 268     if (dTermNotchHz != 0 && pidProfile->dterm_notch_cutoff != 0) {
 269         dtermNotchApplyFn = (filterApplyFnPtr)biquadFilterApply;
 270         const float notchQ = filterGetNotchQ(dTermNotchHz, pidProfile->dterm_notch_cutoff);
 271         for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 272             biquadFilterInit(&dtermNotch[axis], dTermNotchHz, targetPidLooptime, notchQ, FILTER_NOTCH);
 273         }
 274     } else {
 275         dtermNotchApplyFn = nullFilterApply;
 276     }
 277
 278     //1st Dterm Lowpass Filter
 279     if (pidProfile->dterm_lowpass_hz == 0 || pidProfile->dterm_lowpass_hz > pidFrequencyNyquist) {
 280         dtermLowpassApplyFn = nullFilterApply;
 281     } else {
 282         switch (pidProfile->dterm_filter_type) {
 283         case FILTER_PT1:
 284             dtermLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 285             for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 286                 pt1FilterInit(&dtermLowpass[axis].pt1Filter, pt1FilterGain(pidProfile->dterm_lowpass_hz, dT));
 287             }
 288             break;
 289         case FILTER_BIQUAD:
 290 #ifdef USE_DYN_LPF
 291             dtermLowpassApplyFn = (filterApplyFnPtr)biquadFilterApplyDF1;
 292 #else
 293             dtermLowpassApplyFn = (filterApplyFnPtr)biquadFilterApply;
 294 #endif
 295             for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 296                 biquadFilterInitLPF(&dtermLowpass[axis].biquadFilter, pidProfile->dterm_lowpass_hz, targetPidLooptime);
 297             }
 298             break;
 299         default:
 300             dtermLowpassApplyFn = nullFilterApply;
 301             break;
 302         }
 303     }
 304
 305     //2nd Dterm Lowpass Filter
 306     if (pidProfile->dterm_lowpass2_hz == 0 || pidProfile->dterm_lowpass2_hz > pidFrequencyNyquist) {
 307         dtermLowpass2ApplyFn = nullFilterApply;
 308     } else {
 309         switch (pidProfile->dterm_filter2_type) {
 310         case FILTER_PT1:
 311             dtermLowpass2ApplyFn = (filterApplyFnPtr)pt1FilterApply;
 312             for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 313                 pt1FilterInit(&dtermLowpass2[axis].pt1Filter, pt1FilterGain(pidProfile->dterm_lowpass2_hz, dT));
 314             }
 315             break;
 316         case FILTER_BIQUAD:
 317             dtermLowpass2ApplyFn = (filterApplyFnPtr)biquadFilterApply;
 318             for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 319                 biquadFilterInitLPF(&dtermLowpass2[axis].biquadFilter, pidProfile->dterm_lowpass2_hz, targetPidLooptime);
 320             }
 321             break;
 322         default:
 323             dtermLowpass2ApplyFn = nullFilterApply;
 324             break;
 325         }
 326     }
 327
 328     if (pidProfile->yaw_lowpass_hz == 0 || pidProfile->yaw_lowpass_hz > pidFrequencyNyquist) {
 329         ptermYawLowpassApplyFn = nullFilterApply;
 330     } else {
 331         ptermYawLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 332         pt1FilterInit(&ptermYawLowpass, pt1FilterGain(pidProfile->yaw_lowpass_hz, dT));
 333     }
 334
 335 #if defined(USE_THROTTLE_BOOST)
 336     pt1FilterInit(&throttleLpf, pt1FilterGain(pidProfile->throttle_boost_cutoff, dT));
 337 #endif
 338 #if defined(USE_ITERM_RELAX)
 339     if (itermRelax) {
 340         for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 341             pt1FilterInit(&windupLpf[i], pt1FilterGain(itermRelaxCutoff, dT));
 342         }
 343     }
 344 #endif
 345
 346     pt1FilterInit(&antiGravityThrottleLpf, pt1FilterGain(ANTI_GRAVITY_THROTTLE_FILTER_CUTOFF, dT));
 347 }
 348
 349 #ifdef USE_RC_SMOOTHING_FILTER
 350 void pidInitSetpointDerivativeLpf(uint16_t filterCutoff, uint8_t debugAxis, uint8_t filterType)
 351 {
 352     rcSmoothingDebugAxis = debugAxis;
 353     rcSmoothingFilterType = filterType;
 354     if ((filterCutoff > 0) && (rcSmoothingFilterType != RC_SMOOTHING_DERIVATIVE_OFF)) {
 355         setpointDerivativeLpfInitialized = true;
 356         for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 357             switch (rcSmoothingFilterType) {
 358                 case RC_SMOOTHING_DERIVATIVE_PT1:
 359                     pt1FilterInit(&setpointDerivativePt1[axis], pt1FilterGain(filterCutoff, dT));
 360                     break;
 361                 case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 362                     biquadFilterInitLPF(&setpointDerivativeBiquad[axis], filterCutoff, targetPidLooptime);
 363                     break;
 364             }
 365         }
 366     }
 367 }
 368
 369 void pidUpdateSetpointDerivativeLpf(uint16_t filterCutoff)
 370 {
 371     if ((filterCutoff > 0) && (rcSmoothingFilterType != RC_SMOOTHING_DERIVATIVE_OFF)) {
 372         for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 373             switch (rcSmoothingFilterType) {
 374                 case RC_SMOOTHING_DERIVATIVE_PT1:
 375                     pt1FilterUpdateCutoff(&setpointDerivativePt1[axis], pt1FilterGain(filterCutoff, dT));
 376                     break;
 377                 case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 378                     biquadFilterUpdateLPF(&setpointDerivativeBiquad[axis], filterCutoff, targetPidLooptime);
 379                     break;
 380             }
 381         }
 382     }
 383 }
 384 #endif // USE_RC_SMOOTHING_FILTER
 385
 386 typedef struct pidCoefficient_s {
 387     float Kp;
 388     float Ki;
 389     float Kd;
 390     float Kf;
 391 } pidCoefficient_t;
 392
 393 static FAST_RAM_ZERO_INIT pidCoefficient_t pidCoefficient[XYZ_AXIS_COUNT];
 394 static FAST_RAM_ZERO_INIT float maxVelocity[XYZ_AXIS_COUNT];
 395 static FAST_RAM_ZERO_INIT float feedForwardTransition;
 396 static FAST_RAM_ZERO_INIT float levelGain, horizonGain, horizonTransition, horizonCutoffDegrees, horizonFactorRatio;
 397 static FAST_RAM_ZERO_INIT float itermWindupPointInv;
 398 static FAST_RAM_ZERO_INIT uint8_t horizonTiltExpertMode;
 399 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeLimitUs;
 400 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeDelayUs;
 401 static FAST_RAM_ZERO_INIT int32_t crashRecoveryAngleDeciDegrees;
 402 static FAST_RAM_ZERO_INIT float crashRecoveryRate;
 403 static FAST_RAM_ZERO_INIT float crashDtermThreshold;
 404 static FAST_RAM_ZERO_INIT float crashGyroThreshold;
 405 static FAST_RAM_ZERO_INIT float crashSetpointThreshold;
 406 static FAST_RAM_ZERO_INIT float crashLimitYaw;
 407 static FAST_RAM_ZERO_INIT float itermLimit;
 408 #if defined(USE_THROTTLE_BOOST)
 409 FAST_RAM_ZERO_INIT float throttleBoost;
 410 pt1Filter_t throttleLpf;
 411 #endif
 412 static FAST_RAM_ZERO_INIT bool itermRotation;
 413
 414 #if defined(USE_SMART_FEEDFORWARD)
 415 static FAST_RAM_ZERO_INIT bool smartFeedforward;
 416 #endif
 417 #if defined(USE_ABSOLUTE_CONTROL)
 418 STATIC_UNIT_TESTED FAST_RAM_ZERO_INIT float axisError[XYZ_AXIS_COUNT];
 419 static FAST_RAM_ZERO_INIT float acGain;
 420 static FAST_RAM_ZERO_INIT float acLimit;
 421 static FAST_RAM_ZERO_INIT float acErrorLimit;
 422 #endif
 423
 424 void pidResetIterm(void)
 425 {
 426     for (int axis = 0; axis < 3; axis++) {
 427         pidData[axis].I = 0.0f;
 428 #if defined(USE_ABSOLUTE_CONTROL)
 429         axisError[axis] = 0.0f;
 430 #endif
 431     }
 432 }
 433
 434 #ifdef USE_ACRO_TRAINER
 435 static FAST_RAM_ZERO_INIT float acroTrainerAngleLimit;
 436 static FAST_RAM_ZERO_INIT float acroTrainerLookaheadTime;
 437 static FAST_RAM_ZERO_INIT uint8_t acroTrainerDebugAxis;
 438 static FAST_RAM_ZERO_INIT bool acroTrainerActive;
 439 static FAST_RAM_ZERO_INIT int acroTrainerAxisState[2];  // only need roll and pitch
 440 static FAST_RAM_ZERO_INIT float acroTrainerGain;
 441 #endif // USE_ACRO_TRAINER
 442
 443 void pidUpdateAntiGravityThrottleFilter(float throttle)
 444 {
 445     if (antiGravityMode == ANTI_GRAVITY_SMOOTH) {
 446         antiGravityThrottleHpf = throttle - pt1FilterApply(&antiGravityThrottleLpf, throttle);
 447     }
 448 }
 449
 450 #ifdef USE_DYN_LPF
 451 static FAST_RAM int8_t dynLpfFilter = DYN_LPF_NONE;
 452 static FAST_RAM_ZERO_INIT float dynLpfIdle;
 453 static FAST_RAM_ZERO_INIT float dynLpfIdlePoint;
 454 static FAST_RAM_ZERO_INIT float dynLpfInvIdlePointScaled;
 455 static FAST_RAM_ZERO_INIT uint16_t dynLpfMin;
 456 #endif
 457
 458 void pidInitConfig(const pidProfile_t *pidProfile)
 459 {
 460     if (pidProfile->feedForwardTransition == 0) {
 461         feedForwardTransition = 0;
 462     } else {
 463         feedForwardTransition = 100.0f / pidProfile->feedForwardTransition;
 464     }
 465     for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 466         pidCoefficient[axis].Kp = PTERM_SCALE * pidProfile->pid[axis].P;
 467         pidCoefficient[axis].Ki = ITERM_SCALE * pidProfile->pid[axis].I;
 468         pidCoefficient[axis].Kd = DTERM_SCALE * pidProfile->pid[axis].D;
 469         pidCoefficient[axis].Kf = FEEDFORWARD_SCALE * (pidProfile->pid[axis].F / 100.0f);
 470     }
 471
 472     levelGain = pidProfile->pid[PID_LEVEL].P / 10.0f;
 473     horizonGain = pidProfile->pid[PID_LEVEL].I / 10.0f;
 474     horizonTransition = (float)pidProfile->pid[PID_LEVEL].D;
 475     horizonTiltExpertMode = pidProfile->horizon_tilt_expert_mode;
 476     horizonCutoffDegrees = (175 - pidProfile->horizon_tilt_effect) * 1.8f;
 477     horizonFactorRatio = (100 - pidProfile->horizon_tilt_effect) * 0.01f;
 478     maxVelocity[FD_ROLL] = maxVelocity[FD_PITCH] = pidProfile->rateAccelLimit * 100 * dT;
 479     maxVelocity[FD_YAW] = pidProfile->yawRateAccelLimit * 100 * dT;
 480     itermWindupPointInv = 1.0f;
 481     if (pidProfile->itermWindupPointPercent < 100) {
 482         const float itermWindupPoint = pidProfile->itermWindupPointPercent / 100.0f;
 483         itermWindupPointInv = 1.0f / (1.0f - itermWindupPoint);
 484     }
 485     itermAcceleratorGain = pidProfile->itermAcceleratorGain;
 486     crashTimeLimitUs = pidProfile->crash_time * 1000;
 487     crashTimeDelayUs = pidProfile->crash_delay * 1000;
 488     crashRecoveryAngleDeciDegrees = pidProfile->crash_recovery_angle * 10;
 489     crashRecoveryRate = pidProfile->crash_recovery_rate;
 490     crashGyroThreshold = pidProfile->crash_gthreshold;
 491     crashDtermThreshold = pidProfile->crash_dthreshold;
 492     crashSetpointThreshold = pidProfile->crash_setpoint_threshold;
 493     crashLimitYaw = pidProfile->crash_limit_yaw;
 494     itermLimit = pidProfile->itermLimit;
 495 #if defined(USE_THROTTLE_BOOST)
 496     throttleBoost = pidProfile->throttle_boost * 0.1f;
 497 #endif
 498     itermRotation = pidProfile->iterm_rotation;
 499     antiGravityMode = pidProfile->antiGravityMode;
 500
 501     // Calculate the anti-gravity value that will trigger the OSD display.
 502     // For classic AG it's either 1.0 for off and > 1.0 for on.
 503     // For the new AG it's a continuous floating value so we want to trigger the OSD
 504     // display when it exceeds 25% of its possible range. This gives a useful indication
 505     // of AG activity without excessive display.
 506     antiGravityOsdCutoff = 1.0f;
 507     if (antiGravityMode == ANTI_GRAVITY_SMOOTH) {
 508         antiGravityOsdCutoff += ((itermAcceleratorGain - 1000) / 1000.0f) * 0.25f;
 509     }
 510
 511 #if defined(USE_SMART_FEEDFORWARD)
 512     smartFeedforward = pidProfile->smart_feedforward;
 513 #endif
 514 #if defined(USE_ITERM_RELAX)
 515     itermRelax = pidProfile->iterm_relax;
 516     itermRelaxType = pidProfile->iterm_relax_type;
 517     itermRelaxCutoff = pidProfile->iterm_relax_cutoff;
 518 #endif
 519
 520 #ifdef USE_ACRO_TRAINER
 521     acroTrainerAngleLimit = pidProfile->acro_trainer_angle_limit;
 522     acroTrainerLookaheadTime = (float)pidProfile->acro_trainer_lookahead_ms / 1000.0f;
 523     acroTrainerDebugAxis = pidProfile->acro_trainer_debug_axis;
 524     acroTrainerGain = (float)pidProfile->acro_trainer_gain / 10.0f;
 525 #endif // USE_ACRO_TRAINER
 526
 527 #if defined(USE_ABSOLUTE_CONTROL)
 528     acGain = (float)pidProfile->abs_control_gain;
 529     acLimit = (float)pidProfile->abs_control_limit;
 530     acErrorLimit = (float)pidProfile->abs_control_error_limit;
 531 #endif
 532
 533 #ifdef USE_DYN_LPF
 534     if (pidProfile->dyn_lpf_dterm_idle > 0 && pidProfile->dyn_lpf_dterm_max_hz > 0) {
 535         if (pidProfile->dterm_lowpass_hz > 0 ) {
 536             dynLpfMin = pidProfile->dterm_lowpass_hz;
 537             switch (pidProfile->dterm_filter_type) {
 538             case FILTER_PT1:
 539                 dynLpfFilter = DYN_LPF_PT1;
 540                 break;
 541             case FILTER_BIQUAD:
 542                 dynLpfFilter = DYN_LPF_BIQUAD;
 543                 break;
 544             default:
 545                 dynLpfFilter = DYN_LPF_NONE;
 546                 break;
 547             }
 548         }
 549     } else {
 550         dynLpfFilter = DYN_LPF_NONE;
 551     }
 552     dynLpfIdle = pidProfile->dyn_lpf_dterm_idle / 100.0f;
 553     dynLpfIdlePoint = (dynLpfIdle - (dynLpfIdle * dynLpfIdle * dynLpfIdle) / 3.0f) * 1.5f;
 554     dynLpfInvIdlePointScaled = 1 / (1 - dynLpfIdlePoint) * (pidProfile->dyn_lpf_dterm_max_hz - dynLpfMin);
 555 #endif
 556 }
 557
 558 void pidInit(const pidProfile_t *pidProfile)
 559 {
 560     pidSetTargetLooptime(gyro.targetLooptime * pidConfig()->pid_process_denom); // Initialize pid looptime
 561     pidInitFilters(pidProfile);
 562     pidInitConfig(pidProfile);
 563 }
 564
 565 #ifdef USE_ACRO_TRAINER
 566 void pidAcroTrainerInit(void)
 567 {
 568     acroTrainerAxisState[FD_ROLL] = 0;
 569     acroTrainerAxisState[FD_PITCH] = 0;
 570 }
 571 #endif // USE_ACRO_TRAINER
 572
 573 void pidCopyProfile(uint8_t dstPidProfileIndex, uint8_t srcPidProfileIndex)
 574 {
 575     if ((dstPidProfileIndex < MAX_PROFILE_COUNT-1 && srcPidProfileIndex < MAX_PROFILE_COUNT-1)
 576         && dstPidProfileIndex != srcPidProfileIndex
 577     ) {
 578         memcpy(pidProfilesMutable(dstPidProfileIndex), pidProfilesMutable(srcPidProfileIndex), sizeof(pidProfile_t));
 579     }
 580 }
 581
 582 // calculates strength of horizon leveling; 0 = none, 1.0 = most leveling
 583 STATIC_UNIT_TESTED float calcHorizonLevelStrength(void)
 584 {
 585     // start with 1.0 at center stick, 0.0 at max stick deflection:
 586     float horizonLevelStrength = 1.0f - MAX(getRcDeflectionAbs(FD_ROLL), getRcDeflectionAbs(FD_PITCH));
 587
 588     // 0 at level, 90 at vertical, 180 at inverted (degrees):
 589     const float currentInclination = MAX(ABS(attitude.values.roll), ABS(attitude.values.pitch)) / 10.0f;
 590
 591     // horizonTiltExpertMode:  0 = leveling always active when sticks centered,
 592     //                         1 = leveling can be totally off when inverted
 593     if (horizonTiltExpertMode) {
 594         if (horizonTransition > 0 && horizonCutoffDegrees > 0) {
 595                     // if d_level > 0 and horizonTiltEffect < 175
 596             // horizonCutoffDegrees: 0 to 125 => 270 to 90 (represents where leveling goes to zero)
 597             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 598             //  for larger inclinations; 0.0 at horizonCutoffDegrees value:
 599             const float inclinationLevelRatio = constrainf((horizonCutoffDegrees-currentInclination) / horizonCutoffDegrees, 0, 1);
 600             // apply configured horizon sensitivity:
 601                 // when stick is near center (horizonLevelStrength ~= 1.0)
 602                 //  H_sensitivity value has little effect,
 603                 // when stick is deflected (horizonLevelStrength near 0.0)
 604                 //  H_sensitivity value has more effect:
 605             horizonLevelStrength = (horizonLevelStrength - 1) * 100 / horizonTransition + 1;
 606             // apply inclination ratio, which may lower leveling
 607             //  to zero regardless of stick position:
 608             horizonLevelStrength *= inclinationLevelRatio;
 609         } else  { // d_level=0 or horizon_tilt_effect>=175 means no leveling
 610           horizonLevelStrength = 0;
 611         }
 612     } else { // horizon_tilt_expert_mode = 0 (leveling always active when sticks centered)
 613         float sensitFact;
 614         if (horizonFactorRatio < 1.01f) { // if horizonTiltEffect > 0
 615             // horizonFactorRatio: 1.0 to 0.0 (larger means more leveling)
 616             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 617             //  for larger inclinations, goes to 1.0 at inclination==level:
 618             const float inclinationLevelRatio = (180-currentInclination)/180 * (1.0f-horizonFactorRatio) + horizonFactorRatio;
 619             // apply ratio to configured horizon sensitivity:
 620             sensitFact = horizonTransition * inclinationLevelRatio;
 621         } else { // horizonTiltEffect=0 for "old" functionality
 622             sensitFact = horizonTransition;
 623         }
 624
 625         if (sensitFact <= 0) {           // zero means no leveling
 626             horizonLevelStrength = 0;
 627         } else {
 628             // when stick is near center (horizonLevelStrength ~= 1.0)
 629             //  sensitFact value has little effect,
 630             // when stick is deflected (horizonLevelStrength near 0.0)
 631             //  sensitFact value has more effect:
 632             horizonLevelStrength = ((horizonLevelStrength - 1) * (100 / sensitFact)) + 1;
 633         }
 634     }
 635     return constrainf(horizonLevelStrength, 0, 1);
 636 }
 637
 638 STATIC_UNIT_TESTED float pidLevel(int axis, const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, float currentPidSetpoint) {
 639     // calculate error angle and limit the angle to the max inclination
 640     // rcDeflection is in range [-1.0, 1.0]
 641     float angle = pidProfile->levelAngleLimit * getRcDeflection(axis);
 642 #ifdef USE_GPS_RESCUE
 643     angle += gpsRescueAngle[axis] / 100; // ANGLE IS IN CENTIDEGREES
 644 #endif
 645     angle = constrainf(angle, -pidProfile->levelAngleLimit, pidProfile->levelAngleLimit);
 646     const float errorAngle = angle - ((attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f);
 647     if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) {
 648         // ANGLE mode - control is angle based
 649         currentPidSetpoint = errorAngle * levelGain;
 650     } else {
 651         // HORIZON mode - mix of ANGLE and ACRO modes
 652         // mix in errorAngle to currentPidSetpoint to add a little auto-level feel
 653         const float horizonLevelStrength = calcHorizonLevelStrength();
 654         currentPidSetpoint = currentPidSetpoint + (errorAngle * horizonGain * horizonLevelStrength);
 655     }
 656     return currentPidSetpoint;
 657 }
 658
 659 static float accelerationLimit(int axis, float currentPidSetpoint)
 660 {
 661     static float previousSetpoint[XYZ_AXIS_COUNT];
 662     const float currentVelocity = currentPidSetpoint - previousSetpoint[axis];
 663
 664     if (ABS(currentVelocity) > maxVelocity[axis]) {
 665         currentPidSetpoint = (currentVelocity > 0) ? previousSetpoint[axis] + maxVelocity[axis] : previousSetpoint[axis] - maxVelocity[axis];
 666     }
 667
 668     previousSetpoint[axis] = currentPidSetpoint;
 669     return currentPidSetpoint;
 670 }
 671
 672 static timeUs_t crashDetectedAtUs;
 673
 674 static void handleCrashRecovery(
 675     const pidCrashRecovery_e crash_recovery, const rollAndPitchTrims_t *angleTrim,
 676     const int axis, const timeUs_t currentTimeUs, const float gyroRate, float *currentPidSetpoint, float *errorRate)
 677 {
 678     if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeDelayUs) {
 679         if (crash_recovery == PID_CRASH_RECOVERY_BEEP) {
 680             BEEP_ON;
 681         }
 682         if (axis == FD_YAW) {
 683             *errorRate = constrainf(*errorRate, -crashLimitYaw, crashLimitYaw);
 684         } else {
 685             // on roll and pitch axes calculate currentPidSetpoint and errorRate to level the aircraft to recover from crash
 686             if (sensors(SENSOR_ACC)) {
 687                 // errorAngle is deviation from horizontal
 688                 const float errorAngle =  -(attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 689                 *currentPidSetpoint = errorAngle * levelGain;
 690                 *errorRate = *currentPidSetpoint - gyroRate;
 691             }
 692         }
 693         // reset iterm, since accumulated error before crash is now meaningless
 694         // and iterm windup during crash recovery can be extreme, especially on yaw axis
 695         pidData[axis].I = 0.0f;
 696         if (cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeLimitUs
 697             || (getMotorMixRange() < 1.0f
 698                    && ABS(gyro.gyroADCf[FD_ROLL]) < crashRecoveryRate
 699                    && ABS(gyro.gyroADCf[FD_PITCH]) < crashRecoveryRate
 700                    && ABS(gyro.gyroADCf[FD_YAW]) < crashRecoveryRate)) {
 701             if (sensors(SENSOR_ACC)) {
 702                 // check aircraft nearly level
 703                 if (ABS(attitude.raw[FD_ROLL] - angleTrim->raw[FD_ROLL]) < crashRecoveryAngleDeciDegrees
 704                    && ABS(attitude.raw[FD_PITCH] - angleTrim->raw[FD_PITCH]) < crashRecoveryAngleDeciDegrees) {
 705                     inCrashRecoveryMode = false;
 706                     BEEP_OFF;
 707                 }
 708             } else {
 709                 inCrashRecoveryMode = false;
 710                 BEEP_OFF;
 711             }
 712         }
 713     }
 714 }
 715
 716 static void detectAndSetCrashRecovery(
 717     const pidCrashRecovery_e crash_recovery, const int axis,
 718     const timeUs_t currentTimeUs, const float delta, const float errorRate)
 719 {
 720     // if crash recovery is on and accelerometer enabled and there is no gyro overflow, then check for a crash
 721     // no point in trying to recover if the crash is so severe that the gyro overflows
 722     if ((crash_recovery || FLIGHT_MODE(GPS_RESCUE_MODE)) && !gyroOverflowDetected()) {
 723         if (ARMING_FLAG(ARMED)) {
 724             if (getMotorMixRange() >= 1.0f && !inCrashRecoveryMode
 725                 && ABS(delta) > crashDtermThreshold
 726                 && ABS(errorRate) > crashGyroThreshold
 727                 && ABS(getSetpointRate(axis)) < crashSetpointThreshold) {
 728                 inCrashRecoveryMode = true;
 729                 crashDetectedAtUs = currentTimeUs;
 730             }
 731             if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) < crashTimeDelayUs && (ABS(errorRate) < crashGyroThreshold
 732                 || ABS(getSetpointRate(axis)) > crashSetpointThreshold)) {
 733                 inCrashRecoveryMode = false;
 734                 BEEP_OFF;
 735             }
 736         } else if (inCrashRecoveryMode) {
 737             inCrashRecoveryMode = false;
 738             BEEP_OFF;
 739         }
 740     }
 741 }
 742
 743 static void rotateVector(float v[XYZ_AXIS_COUNT], float rotation[XYZ_AXIS_COUNT])
 744 {
 745     // rotate v around rotation vector rotation
 746     // rotation in radians, all elements must be small
 747     for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 748         int i_1 = (i + 1) % 3;
 749         int i_2 = (i + 2) % 3;
 750         float newV = v[i_1] + v[i_2] * rotation[i];
 751         v[i_2] -= v[i_1] * rotation[i];
 752         v[i_1] = newV;
 753     }
 754 }
 755
 756 STATIC_UNIT_TESTED void rotateItermAndAxisError()
 757 {
 758     if (itermRotation
 759 #if defined(USE_ABSOLUTE_CONTROL)
 760         || acGain > 0
 761 #endif
 762         ) {
 763         const float gyroToAngle = dT * RAD;
 764         float rotationRads[XYZ_AXIS_COUNT];
 765         for (int i = FD_ROLL; i <= FD_YAW; i++) {
 766             rotationRads[i] = gyro.gyroADCf[i] * gyroToAngle;
 767         }
 768 #if defined(USE_ABSOLUTE_CONTROL)
 769         if (acGain > 0) {
 770             rotateVector(axisError, rotationRads);
 771         }
 772 #endif
 773         if (itermRotation) {
 774             float v[XYZ_AXIS_COUNT];
 775             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 776                 v[i] = pidData[i].I;
 777             }
 778             rotateVector(v, rotationRads );
 779             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 780                 pidData[i].I = v[i];
 781             }
 782         }
 783     }
 784 }
 785
 786 #ifdef USE_ACRO_TRAINER
 787
 788 int acroTrainerSign(float x)
 789 {
 790     return x > 0 ? 1 : -1;
 791 }
 792
 793 // Acro Trainer - Manipulate the setPoint to limit axis angle while in acro mode
 794 // There are three states:
 795 // 1. Current angle has exceeded limit
 796 //    Apply correction to return to limit (similar to pidLevel)
 797 // 2. Future overflow has been projected based on current angle and gyro rate
 798 //    Manage the setPoint to control the gyro rate as the actual angle  approaches the limit (try to prevent overshoot)
 799 // 3. If no potential overflow is detected, then return the original setPoint
 800
 801 // Use the FAST_CODE_NOINLINE directive to avoid this code from being inlined into ITCM RAM. We accept the
 802 // performance decrease when Acro Trainer mode is active under the assumption that user is unlikely to be
 803 // expecting ultimate flight performance at very high loop rates when in this mode.
 804 static FAST_CODE_NOINLINE float applyAcroTrainer(int axis, const rollAndPitchTrims_t *angleTrim, float setPoint)
 805 {
 806     float ret = setPoint;
 807
 808     if (!FLIGHT_MODE(ANGLE_MODE) && !FLIGHT_MODE(HORIZON_MODE) && !FLIGHT_MODE(GPS_RESCUE_MODE)) {
 809         bool resetIterm = false;
 810         float projectedAngle = 0;
 811         const int setpointSign = acroTrainerSign(setPoint);
 812         const float currentAngle = (attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 813         const int angleSign = acroTrainerSign(currentAngle);
 814
 815         if ((acroTrainerAxisState[axis] != 0) && (acroTrainerAxisState[axis] != setpointSign)) {  // stick has reversed - stop limiting
 816             acroTrainerAxisState[axis] = 0;
 817         }
 818
 819         // Limit and correct the angle when it exceeds the limit
 820         if ((fabsf(currentAngle) > acroTrainerAngleLimit) && (acroTrainerAxisState[axis] == 0)) {
 821             if (angleSign == setpointSign) {
 822                 acroTrainerAxisState[axis] = angleSign;
 823                 resetIterm = true;
 824             }
 825         }
 826
 827         if (acroTrainerAxisState[axis] != 0) {
 828             ret = constrainf(((acroTrainerAngleLimit * angleSign) - currentAngle) * acroTrainerGain, -ACRO_TRAINER_SETPOINT_LIMIT, ACRO_TRAINER_SETPOINT_LIMIT);
 829         } else {
 830
 831         // Not currently over the limit so project the angle based on current angle and
 832         // gyro angular rate using a sliding window based on gyro rate (faster rotation means larger window.
 833         // If the projected angle exceeds the limit then apply limiting to minimize overshoot.
 834             // Calculate the lookahead window by scaling proportionally with gyro rate from 0-500dps
 835             float checkInterval = constrainf(fabsf(gyro.gyroADCf[axis]) / ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT, 0.0f, 1.0f) * acroTrainerLookaheadTime;
 836             projectedAngle = (gyro.gyroADCf[axis] * checkInterval) + currentAngle;
 837             const int projectedAngleSign = acroTrainerSign(projectedAngle);
 838             if ((fabsf(projectedAngle) > acroTrainerAngleLimit) && (projectedAngleSign == setpointSign)) {
 839                 ret = ((acroTrainerAngleLimit * projectedAngleSign) - projectedAngle) * acroTrainerGain;
 840                 resetIterm = true;
 841             }
 842         }
 843
 844         if (resetIterm) {
 845             pidData[axis].I = 0;
 846         }
 847
 848         if (axis == acroTrainerDebugAxis) {
 849             DEBUG_SET(DEBUG_ACRO_TRAINER, 0, lrintf(currentAngle * 10.0f));
 850             DEBUG_SET(DEBUG_ACRO_TRAINER, 1, acroTrainerAxisState[axis]);
 851             DEBUG_SET(DEBUG_ACRO_TRAINER, 2, lrintf(ret));
 852             DEBUG_SET(DEBUG_ACRO_TRAINER, 3, lrintf(projectedAngle * 10.0f));
 853         }
 854     }
 855
 856     return ret;
 857 }
 858 #endif // USE_ACRO_TRAINER
 859
 860 #ifdef USE_RC_SMOOTHING_FILTER
 861 float FAST_CODE applyRcSmoothingDerivativeFilter(int axis, float pidSetpointDelta)
 862 {
 863     float ret = pidSetpointDelta;
 864     if (axis == rcSmoothingDebugAxis) {
 865         DEBUG_SET(DEBUG_RC_SMOOTHING, 1, lrintf(pidSetpointDelta * 100.0f));
 866     }
 867     if (setpointDerivativeLpfInitialized) {
 868         switch (rcSmoothingFilterType) {
 869             case RC_SMOOTHING_DERIVATIVE_PT1:
 870                 ret = pt1FilterApply(&setpointDerivativePt1[axis], pidSetpointDelta);
 871                 break;
 872             case RC_SMOOTHING_DERIVATIVE_BIQUAD:
 873                 ret = biquadFilterApplyDF1(&setpointDerivativeBiquad[axis], pidSetpointDelta);
 874                 break;
 875         }
 876         if (axis == rcSmoothingDebugAxis) {
 877             DEBUG_SET(DEBUG_RC_SMOOTHING, 2, lrintf(ret * 100.0f));
 878         }
 879     }
 880     return ret;
 881 }
 882 #endif // USE_RC_SMOOTHING_FILTER
 883
 884 #ifdef USE_SMART_FEEDFORWARD
 885 void FAST_CODE applySmartFeedforward(int axis)
 886 {
 887     if (smartFeedforward) {
 888         if (pidData[axis].P * pidData[axis].F > 0) {
 889             if (ABS(pidData[axis].F) > ABS(pidData[axis].P)) {
 890                 pidData[axis].P = 0;
 891             } else {
 892                 pidData[axis].F = 0;
 893             }
 894         }
 895     }
 896 }
 897 #endif // USE_SMART_FEEDFORWARD
 898
 899 #if defined(USE_ABSOLUTE_CONTROL)
 900 STATIC_UNIT_TESTED void applyAbsoluteControl(const int axis, const float gyroRate, const bool itermRelaxIsEnabled,
 901     const float setpointLpf, const float setpointHpf,
 902     float *currentPidSetpoint, float *itermErrorRate)
 903 {
 904     if (acGain > 0) {
 905         float acErrorRate = 0;
 906         if (itermRelaxIsEnabled) {
 907             const float gmaxac = setpointLpf + 2 * setpointHpf;
 908             const float gminac = setpointLpf - 2 * setpointHpf;
 909             if (gyroRate >= gminac && gyroRate <= gmaxac) {
 910                 const float acErrorRate1 = gmaxac - gyroRate;
 911                 const float acErrorRate2 = gminac - gyroRate;
 912                 if (acErrorRate1 * axisError[axis] < 0) {
 913                     acErrorRate = acErrorRate1;
 914                 } else {
 915                     acErrorRate = acErrorRate2;
 916                 }
 917                 if (fabsf(acErrorRate * dT) > fabsf(axisError[axis]) ) {
 918                     acErrorRate = -axisError[axis] * pidFrequency;
 919                 }
 920             } else {
 921                 acErrorRate = (gyroRate > gmaxac ? gmaxac : gminac ) - gyroRate;
 922             }
 923         } else {
 924             acErrorRate = *itermErrorRate;
 925         }
 926
 927         if (isAirmodeActivated()) {
 928             axisError[axis] = constrainf(axisError[axis] + acErrorRate * dT,
 929                 -acErrorLimit, acErrorLimit);
 930             const float acCorrection = constrainf(axisError[axis] * acGain, -acLimit, acLimit);
 931             *currentPidSetpoint += acCorrection;
 932             *itermErrorRate += acCorrection;
 933             if (axis == FD_ROLL) {
 934                 DEBUG_SET(DEBUG_ITERM_RELAX, 3, lrintf(axisError[axis] * 10));
 935             }
 936         }
 937     }
 938 }
 939 #endif
 940
 941 #if defined(USE_ITERM_RELAX)
 942 STATIC_UNIT_TESTED void applyItermRelax(const int axis, const float iterm,
 943     const float gyroRate, float *itermErrorRate, float *currentPidSetpoint)
 944 {
 945     const float setpointLpf = pt1FilterApply(&windupLpf[axis], *currentPidSetpoint);
 946     const float setpointHpf = fabsf(*currentPidSetpoint - setpointLpf);
 947     bool itermRelaxIsEnabled = false;
 948
 949     if (itermRelax &&
 950        (axis < FD_YAW || itermRelax == ITERM_RELAX_RPY ||
 951        itermRelax == ITERM_RELAX_RPY_INC)) {
 952         itermRelaxIsEnabled = true;
 953         const float itermRelaxFactor = 1 - setpointHpf / ITERM_RELAX_SETPOINT_THRESHOLD;
 954
 955         const bool isDecreasingI =
 956             ((iterm > 0) && (*itermErrorRate < 0)) || ((iterm < 0) && (*itermErrorRate > 0));
 957         if ((itermRelax >= ITERM_RELAX_RP_INC) && isDecreasingI) {
 958             // Do Nothing, use the precalculed itermErrorRate
 959         } else if (itermRelaxType == ITERM_RELAX_SETPOINT && setpointHpf < ITERM_RELAX_SETPOINT_THRESHOLD) {
 960             *itermErrorRate *= itermRelaxFactor;
 961         } else if (itermRelaxType == ITERM_RELAX_GYRO ) {
 962             *itermErrorRate = fapplyDeadband(setpointLpf - gyroRate, setpointHpf);
 963         } else {
 964             *itermErrorRate = 0.0f;
 965         }
 966
 967         if (axis == FD_ROLL) {
 968             DEBUG_SET(DEBUG_ITERM_RELAX, 0, lrintf(setpointHpf));
 969             DEBUG_SET(DEBUG_ITERM_RELAX, 1, lrintf(itermRelaxFactor * 100.0f));
 970             DEBUG_SET(DEBUG_ITERM_RELAX, 2, lrintf(*itermErrorRate));
 971         }
 972     } else {
 973 #if defined(USE_ABSOLUTE_CONTROL)
 974         applyAbsoluteControl(axis, gyroRate, setpointLpf, setpointHpf, itermRelaxIsEnabled, currentPidSetpoint, itermErrorRate);
 975 #else
 976     UNUSED(itermRelaxIsEnabled);
 977 #endif
 978     }
 979 }
 980 #endif
 981
 982 // Betaflight pid controller, which will be maintained in the future with additional features specialised for current (mini) multirotor usage.
 983 // Based on 2DOF reference design (matlab)
 984 void FAST_CODE pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, timeUs_t currentTimeUs)
 985 {
 986     static float previousGyroRateDterm[XYZ_AXIS_COUNT];
 987     static float previousPidSetpoint[XYZ_AXIS_COUNT];
 988
 989     const float tpaFactor = getThrottlePIDAttenuation();
 990
 991 #ifdef USE_YAW_SPIN_RECOVERY
 992     const bool yawSpinActive = gyroYawSpinDetected();
 993 #endif
 994
 995     // Dynamic i component,
 996     if ((antiGravityMode == ANTI_GRAVITY_SMOOTH) && antiGravityEnabled) {
 997         itermAccelerator = 1 + fabsf(antiGravityThrottleHpf) * 0.01f * (itermAcceleratorGain - 1000);
 998         DEBUG_SET(DEBUG_ANTI_GRAVITY, 1, lrintf(antiGravityThrottleHpf * 1000));
 999     }
1000     DEBUG_SET(DEBUG_ANTI_GRAVITY, 0, lrintf(itermAccelerator * 1000));
1001
1002     // gradually scale back integration when above windup point
1003     float dynCi = dT * itermAccelerator;
1004     if (itermWindupPointInv > 1.0f) {
1005         dynCi *= constrainf((1.0f - getMotorMixRange()) * itermWindupPointInv, 0.0f, 1.0f);
1006     }
1007
1008     // Precalculate gyro deta for D-term here, this allows loop unrolling
1009     float gyroRateDterm[XYZ_AXIS_COUNT];
1010     for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
1011         gyroRateDterm[axis] = dtermNotchApplyFn((filter_t *) &dtermNotch[axis], gyro.gyroADCf[axis]);
1012         gyroRateDterm[axis] = dtermLowpassApplyFn((filter_t *) &dtermLowpass[axis], gyroRateDterm[axis]);
1013         gyroRateDterm[axis] = dtermLowpass2ApplyFn((filter_t *) &dtermLowpass2[axis], gyroRateDterm[axis]);
1014     }
1015
1016     rotateItermAndAxisError();
1017
1018     // ----------PID controller----------
1019     for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
1020
1021         float currentPidSetpoint = getSetpointRate(axis);
1022         if (maxVelocity[axis]) {
1023             currentPidSetpoint = accelerationLimit(axis, currentPidSetpoint);
1024         }
1025         // Yaw control is GYRO based, direct sticks control is applied to rate PID
1026         if ((FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) && axis != FD_YAW) {
1027             currentPidSetpoint = pidLevel(axis, pidProfile, angleTrim, currentPidSetpoint);
1028         }
1029
1030 #ifdef USE_ACRO_TRAINER
1031         if ((axis != FD_YAW) && acroTrainerActive && !inCrashRecoveryMode) {
1032             currentPidSetpoint = applyAcroTrainer(axis, angleTrim, currentPidSetpoint);
1033         }
1034 #endif // USE_ACRO_TRAINER
1035
1036         // Handle yaw spin recovery - zero the setpoint on yaw to aid in recovery
1037         // It's not necessary to zero the set points for R/P because the PIDs will be zeroed below
1038 #ifdef USE_YAW_SPIN_RECOVERY
1039         if ((axis == FD_YAW) && yawSpinActive) {
1040             currentPidSetpoint = 0.0f;
1041         }
1042 #endif // USE_YAW_SPIN_RECOVERY
1043
1044         // -----calculate error rate
1045         const float gyroRate = gyro.gyroADCf[axis]; // Process variable from gyro output in deg/sec
1046         float errorRate = currentPidSetpoint - gyroRate; // r - y
1047         handleCrashRecovery(
1048             pidProfile->crash_recovery, angleTrim, axis, currentTimeUs, gyroRate,
1049             &currentPidSetpoint, &errorRate);
1050
1051         const float iterm = pidData[axis].I;
1052         float itermErrorRate = errorRate;
1053
1054 #if defined(USE_ITERM_RELAX)
1055         applyItermRelax(axis, iterm, gyroRate, &itermErrorRate, &currentPidSetpoint);
1056 #endif
1057
1058         // --------low-level gyro-based PID based on 2DOF PID controller. ----------
1059         // 2-DOF PID controller with optional filter on derivative term.
1060         // b = 1 and only c (feedforward weight) can be tuned (amount derivative on measurement or error).
1061
1062         // -----calculate P component
1063         pidData[axis].P = pidCoefficient[axis].Kp * errorRate * tpaFactor;
1064         if (axis == FD_YAW) {
1065             pidData[axis].P = ptermYawLowpassApplyFn((filter_t *) &ptermYawLowpass, pidData[axis].P);
1066         }
1067
1068         // -----calculate I component
1069         pidData[axis].I = constrainf(iterm + pidCoefficient[axis].Ki * itermErrorRate * dynCi, -itermLimit, itermLimit);
1070
1071         // -----calculate D component
1072         if (pidCoefficient[axis].Kd > 0) {
1073
1074             // Divide rate change by dT to get differential (ie dr/dt).
1075             // dT is fixed and calculated from the target PID loop time
1076             // This is done to avoid DTerm spikes that occur with dynamically
1077             // calculated deltaT whenever another task causes the PID
1078             // loop execution to be delayed.
1079             const float delta =
1080                 - (gyroRateDterm[axis] - previousGyroRateDterm[axis]) * pidFrequency;
1081
1082             detectAndSetCrashRecovery(pidProfile->crash_recovery, axis, currentTimeUs, delta, errorRate);
1083
1084             pidData[axis].D = pidCoefficient[axis].Kd * delta * tpaFactor;
1085         } else {
1086             pidData[axis].D = 0;
1087         }
1088         previousGyroRateDterm[axis] = gyroRateDterm[axis];
1089
1090         // -----calculate feedforward component
1091
1092         // Only enable feedforward for rate mode
1093         const float feedforwardGain = flightModeFlags ? 0.0f : pidCoefficient[axis].Kf;
1094
1095         if (feedforwardGain > 0) {
1096
1097             // no transition if feedForwardTransition == 0
1098             float transition = feedForwardTransition > 0 ? MIN(1.f, getRcDeflectionAbs(axis) * feedForwardTransition) : 1;
1099
1100             float pidSetpointDelta = currentPidSetpoint - previousPidSetpoint[axis];
1101
1102 #ifdef USE_RC_SMOOTHING_FILTER
1103             pidSetpointDelta = applyRcSmoothingDerivativeFilter(axis, pidSetpointDelta);
1104 #endif // USE_RC_SMOOTHING_FILTER
1105
1106             pidData[axis].F = feedforwardGain * transition * pidSetpointDelta * pidFrequency;
1107
1108 #if defined(USE_SMART_FEEDFORWARD)
1109             applySmartFeedforward(axis);
1110 #endif
1111         } else {
1112             pidData[axis].F = 0;
1113         }
1114         previousPidSetpoint[axis] = currentPidSetpoint;
1115
1116 #ifdef USE_YAW_SPIN_RECOVERY
1117         if (yawSpinActive) {
1118             pidData[axis].I = 0;  // in yaw spin always disable I
1119             if (axis <= FD_PITCH)  {
1120                 // zero PIDs on pitch and roll leaving yaw P to correct spin
1121                 pidData[axis].P = 0;
1122                 pidData[axis].D = 0;
1123                 pidData[axis].F = 0;
1124             }
1125         }
1126 #endif // USE_YAW_SPIN_RECOVERY
1127
1128         // calculating the PID sum
1129         pidData[axis].Sum = pidData[axis].P + pidData[axis].I + pidData[axis].D + pidData[axis].F;
1130     }
1131
1132     // Disable PID control if at zero throttle or if gyro overflow detected
1133     // This may look very innefficient, but it is done on purpose to always show real CPU usage as in flight
1134     if (!pidStabilisationEnabled || gyroOverflowDetected()) {
1135         for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
1136             pidData[axis].P = 0;
1137             pidData[axis].I = 0;
1138             pidData[axis].D = 0;
1139             pidData[axis].F = 0;
1140
1141             pidData[axis].Sum = 0;
1142         }
1143     }
1144 }
1145
1146 bool crashRecoveryModeActive(void)
1147 {
1148     return inCrashRecoveryMode;
1149 }
1150
1151 #ifdef USE_ACRO_TRAINER
1152 void pidSetAcroTrainerState(bool newState)
1153 {
1154     if (acroTrainerActive != newState) {
1155         if (newState) {
1156             pidAcroTrainerInit();
1157         }
1158         acroTrainerActive = newState;
1159     }
1160 }
1161 #endif // USE_ACRO_TRAINER
1162
1163 void pidSetAntiGravityState(bool newState)
1164 {
1165     if (newState != antiGravityEnabled) {
1166         // reset the accelerator on state changes
1167         itermAccelerator = 1.0f;
1168     }
1169     antiGravityEnabled = newState;
1170 }
1171
1172 bool pidAntiGravityEnabled(void)
1173 {
1174     return antiGravityEnabled;
1175 }
1176
1177 #ifdef USE_DYN_LPF
1178 void dynLpfDTermUpdate(float throttle)
1179 {
1180     if (dynLpfFilter != DYN_LPF_NONE) {
1181         uint16_t cutoffFreq = dynLpfMin;
1182         if (throttle > dynLpfIdle) {
1183             const float dynThrottle = (throttle - (throttle * throttle * throttle) / 3.0f) * 1.5f;
1184             cutoffFreq += (dynThrottle - dynLpfIdlePoint) * dynLpfInvIdlePointScaled;
1185          }
1186
1187          if (dynLpfFilter == DYN_LPF_PT1) {
1188             for (int axis = 0; axis < XYZ_AXIS_COUNT; axis++) {
1189                 pt1FilterUpdateCutoff(&dtermLowpass[axis].pt1Filter, pt1FilterGain(cutoffFreq, dT));
1190             }
1191         } else {
1192             for (int axis = 0; axis < XYZ_AXIS_COUNT; axis++) {
1193                 biquadFilterUpdateLPF(&dtermLowpass[axis].biquadFilter, cutoffFreq, targetPidLooptime);
1194             }
1195         }
1196     }
1197 }
1198 #endif