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
  68 PG_REGISTER_WITH_RESET_TEMPLATE(pidConfig_t, pidConfig, PG_PID_CONFIG, 2);
  69
  70 #ifdef STM32F10X
  71 #define PID_PROCESS_DENOM_DEFAULT       1
  72 #elif defined(USE_GYRO_SPI_MPU6000) || defined(USE_GYRO_SPI_MPU6500)  || defined(USE_GYRO_SPI_ICM20689)
  73 #define PID_PROCESS_DENOM_DEFAULT       4
  74 #else
  75 #define PID_PROCESS_DENOM_DEFAULT       2
  76 #endif
  77
  78 #ifdef USE_RUNAWAY_TAKEOFF
  79 PG_RESET_TEMPLATE(pidConfig_t, pidConfig,
  80     .pid_process_denom = PID_PROCESS_DENOM_DEFAULT,
  81     .runaway_takeoff_prevention = true,
  82     .runaway_takeoff_deactivate_throttle = 25,  // throttle level % needed to accumulate deactivation time
  83     .runaway_takeoff_deactivate_delay = 500     // Accumulated time (in milliseconds) before deactivation in successful takeoff
  84 );
  85 #else
  86 PG_RESET_TEMPLATE(pidConfig_t, pidConfig,
  87     .pid_process_denom = PID_PROCESS_DENOM_DEFAULT
  88 );
  89 #endif
  90
  91 PG_REGISTER_ARRAY_WITH_RESET_FN(pidProfile_t, MAX_PROFILE_COUNT, pidProfiles, PG_PID_PROFILE, 3);
  92
  93 void resetPidProfile(pidProfile_t *pidProfile)
  94 {
  95     RESET_CONFIG(pidProfile_t, pidProfile,
  96         .pid = {
  97             [PID_ROLL] =  { 40, 40, 30 },
  98             [PID_PITCH] = { 58, 50, 35 },
  99             [PID_YAW] =   { 70, 45, 20 },
 100             [PID_ALT] =   { 50, 0, 0 },
 101             [PID_POS] =   { 15, 0, 0 },     // POSHOLD_P * 100, POSHOLD_I * 100,
 102             [PID_POSR] =  { 34, 14, 53 },   // POSHOLD_RATE_P * 10, POSHOLD_RATE_I * 100, POSHOLD_RATE_D * 1000,
 103             [PID_NAVR] =  { 25, 33, 83 },   // NAV_P * 10, NAV_I * 100, NAV_D * 1000
 104             [PID_LEVEL] = { 50, 50, 75 },
 105             [PID_MAG] =   { 40, 0, 0 },
 106             [PID_VEL] =   { 55, 55, 75 }
 107         },
 108
 109         .pidSumLimit = PIDSUM_LIMIT,
 110         .pidSumLimitYaw = PIDSUM_LIMIT_YAW,
 111         .yaw_lowpass_hz = 0,
 112         .dterm_lowpass_hz = 100,    // filtering ON by default
 113         .dterm_lowpass2_hz = 0,    // second Dterm LPF OFF by default
 114         .dterm_notch_hz = 260,
 115         .dterm_notch_cutoff = 160,
 116         .dterm_filter_type = FILTER_BIQUAD,
 117         .itermWindupPointPercent = 50,
 118         .vbatPidCompensation = 0,
 119         .pidAtMinThrottle = PID_STABILISATION_ON,
 120         .levelAngleLimit = 55,
 121         .setpointRelaxRatio = 100,
 122         .dtermSetpointWeight = 0,
 123         .yawRateAccelLimit = 100,
 124         .rateAccelLimit = 0,
 125         .itermThrottleThreshold = 350,
 126         .itermAcceleratorGain = 1000,
 127         .crash_time = 500,          // ms
 128         .crash_delay = 0,           // ms
 129         .crash_recovery_angle = 10, // degrees
 130         .crash_recovery_rate = 100, // degrees/second
 131         .crash_dthreshold = 50,     // degrees/second/second
 132         .crash_gthreshold = 400,    // degrees/second
 133         .crash_setpoint_threshold = 350, // degrees/second
 134         .crash_recovery = PID_CRASH_RECOVERY_OFF, // off by default
 135         .horizon_tilt_effect = 75,
 136         .horizon_tilt_expert_mode = false,
 137         .crash_limit_yaw = 200,
 138         .itermLimit = 150,
 139         .throttle_boost = 0,
 140         .throttle_boost_cutoff = 15,
 141         .iterm_rotation = false,
 142         .smart_feedforward = false,
 143         .iterm_relax = false,
 144         .iterm_relax_cutoff_low = 3,
 145         .iterm_relax_cutoff_high = 15,
 146     );
 147 }
 148
 149 void pgResetFn_pidProfiles(pidProfile_t *pidProfiles)
 150 {
 151     for (int i = 0; i < MAX_PROFILE_COUNT; i++) {
 152         resetPidProfile(&pidProfiles[i]);
 153     }
 154 }
 155
 156 static void pidSetTargetLooptime(uint32_t pidLooptime)
 157 {
 158     targetPidLooptime = pidLooptime;
 159     dT = (float)targetPidLooptime * 0.000001f;
 160 }
 161
 162 void pidResetITerm(void)
 163 {
 164     for (int axis = 0; axis < 3; axis++) {
 165         pidData[axis].I = 0.0f;
 166     }
 167 }
 168
 169 static FAST_RAM float itermAccelerator = 1.0f;
 170
 171 void pidSetItermAccelerator(float newItermAccelerator)
 172 {
 173     itermAccelerator = newItermAccelerator;
 174 }
 175
 176 float pidItermAccelerator(void)
 177 {
 178     return itermAccelerator;
 179 }
 180
 181 void pidStabilisationState(pidStabilisationState_e pidControllerState)
 182 {
 183     pidStabilisationEnabled = (pidControllerState == PID_STABILISATION_ON) ? true : false;
 184 }
 185
 186 const angle_index_t rcAliasToAngleIndexMap[] = { AI_ROLL, AI_PITCH };
 187
 188 typedef union dtermLowpass_u {
 189     pt1Filter_t pt1Filter;
 190     biquadFilter_t biquadFilter;
 191 #if defined(USE_FIR_FILTER_DENOISE)
 192     firFilterDenoise_t denoisingFilter;
 193 #endif
 194 } dtermLowpass_t;
 195
 196 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermNotchApplyFn;
 197 static FAST_RAM_ZERO_INIT biquadFilter_t dtermNotch[2];
 198 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpassApplyFn;
 199 static FAST_RAM_ZERO_INIT dtermLowpass_t dtermLowpass[2];
 200 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpass2ApplyFn;
 201 static FAST_RAM_ZERO_INIT pt1Filter_t dtermLowpass2[2];
 202 static FAST_RAM_ZERO_INIT filterApplyFnPtr ptermYawLowpassApplyFn;
 203 static FAST_RAM_ZERO_INIT pt1Filter_t ptermYawLowpass;
 204 static FAST_RAM_ZERO_INIT pt1Filter_t windupLpf[3][2];
 205 static FAST_RAM_ZERO_INIT bool itermRelax;
 206 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoffLow;
 207 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoffHigh;
 208
 209 void pidInitFilters(const pidProfile_t *pidProfile)
 210 {
 211     BUILD_BUG_ON(FD_YAW != 2); // only setting up Dterm filters on roll and pitch axes, so ensure yaw axis is 2
 212
 213     if (targetPidLooptime == 0) {
 214         // no looptime set, so set all the filters to null
 215         dtermNotchApplyFn = nullFilterApply;
 216         dtermLowpassApplyFn = nullFilterApply;
 217         ptermYawLowpassApplyFn = nullFilterApply;
 218         return;
 219     }
 220
 221     const uint32_t pidFrequencyNyquist = (1.0f / dT) / 2; // No rounding needed
 222
 223     uint16_t dTermNotchHz;
 224     if (pidProfile->dterm_notch_hz <= pidFrequencyNyquist) {
 225         dTermNotchHz = pidProfile->dterm_notch_hz;
 226     } else {
 227         if (pidProfile->dterm_notch_cutoff < pidFrequencyNyquist) {
 228             dTermNotchHz = pidFrequencyNyquist;
 229         } else {
 230             dTermNotchHz = 0;
 231         }
 232     }
 233
 234     if (dTermNotchHz != 0 && pidProfile->dterm_notch_cutoff != 0) {
 235         dtermNotchApplyFn = (filterApplyFnPtr)biquadFilterApply;
 236         const float notchQ = filterGetNotchQ(dTermNotchHz, pidProfile->dterm_notch_cutoff);
 237         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 238             biquadFilterInit(&dtermNotch[axis], dTermNotchHz, targetPidLooptime, notchQ, FILTER_NOTCH);
 239         }
 240     } else {
 241         dtermNotchApplyFn = nullFilterApply;
 242     }
 243
 244     //2nd Dterm Lowpass Filter
 245     if (pidProfile->dterm_lowpass2_hz == 0 || pidProfile->dterm_lowpass2_hz > pidFrequencyNyquist) {
 246         dtermLowpass2ApplyFn = nullFilterApply;
 247     } else {
 248         dtermLowpass2ApplyFn = (filterApplyFnPtr)pt1FilterApply;
 249         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 250             pt1FilterInit(&dtermLowpass2[axis], pt1FilterGain(pidProfile->dterm_lowpass2_hz, dT));
 251         }
 252     }
 253
 254     if (pidProfile->dterm_lowpass_hz == 0 || pidProfile->dterm_lowpass_hz > pidFrequencyNyquist) {
 255         dtermLowpassApplyFn = nullFilterApply;
 256     } else {
 257         switch (pidProfile->dterm_filter_type) {
 258         default:
 259             dtermLowpassApplyFn = nullFilterApply;
 260             break;
 261         case FILTER_PT1:
 262             dtermLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 263             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 264                 pt1FilterInit(&dtermLowpass[axis].pt1Filter, pt1FilterGain(pidProfile->dterm_lowpass_hz, dT));
 265             }
 266             break;
 267         case FILTER_BIQUAD:
 268             dtermLowpassApplyFn = (filterApplyFnPtr)biquadFilterApply;
 269             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 270                 biquadFilterInitLPF(&dtermLowpass[axis].biquadFilter, pidProfile->dterm_lowpass_hz, targetPidLooptime);
 271             }
 272             break;
 273 #if defined(USE_FIR_FILTER_DENOISE)
 274         case FILTER_FIR:
 275             dtermLowpassApplyFn = (filterApplyFnPtr)firFilterDenoiseUpdate;
 276             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 277                 firFilterDenoiseInit(&dtermLowpass[axis].denoisingFilter, pidProfile->dterm_lowpass_hz, targetPidLooptime);
 278             }
 279             break;
 280 #endif
 281         }
 282     }
 283
 284     if (pidProfile->yaw_lowpass_hz == 0 || pidProfile->yaw_lowpass_hz > pidFrequencyNyquist) {
 285         ptermYawLowpassApplyFn = nullFilterApply;
 286     } else {
 287         ptermYawLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 288         pt1FilterInit(&ptermYawLowpass, pt1FilterGain(pidProfile->yaw_lowpass_hz, dT));
 289     }
 290
 291     pt1FilterInit(&throttleLpf, pt1FilterGain(pidProfile->throttle_boost_cutoff, dT));
 292     if (itermRelax)
 293         for (int i = 0; i < 3; i++) {
 294             pt1FilterInit(&windupLpf[i][0], pt1FilterGain(itermRelaxCutoffLow, dT));
 295             pt1FilterInit(&windupLpf[i][1], pt1FilterGain(itermRelaxCutoffHigh, dT));
 296         }
 297 }
 298
 299 typedef struct pidCoefficient_s {
 300     float Kp;
 301     float Ki;
 302     float Kd;
 303 } pidCoefficient_t;
 304
 305 static FAST_RAM_ZERO_INIT pidCoefficient_t pidCoefficient[3];
 306 static FAST_RAM_ZERO_INIT float maxVelocity[3];
 307 static FAST_RAM_ZERO_INIT float relaxFactor;
 308 static FAST_RAM_ZERO_INIT float dtermSetpointWeight;
 309 static FAST_RAM_ZERO_INIT float levelGain, horizonGain, horizonTransition, horizonCutoffDegrees, horizonFactorRatio;
 310 static FAST_RAM_ZERO_INIT float ITermWindupPointInv;
 311 static FAST_RAM_ZERO_INIT uint8_t horizonTiltExpertMode;
 312 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeLimitUs;
 313 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeDelayUs;
 314 static FAST_RAM_ZERO_INIT int32_t crashRecoveryAngleDeciDegrees;
 315 static FAST_RAM_ZERO_INIT float crashRecoveryRate;
 316 static FAST_RAM_ZERO_INIT float crashDtermThreshold;
 317 static FAST_RAM_ZERO_INIT float crashGyroThreshold;
 318 static FAST_RAM_ZERO_INIT float crashSetpointThreshold;
 319 static FAST_RAM_ZERO_INIT float crashLimitYaw;
 320 static FAST_RAM_ZERO_INIT float itermLimit;
 321 FAST_RAM_ZERO_INIT float throttleBoost;
 322 pt1Filter_t throttleLpf;
 323 static FAST_RAM_ZERO_INIT bool itermRotation;
 324 static FAST_RAM_ZERO_INIT bool smartFeedforward;
 325
 326 void pidInitConfig(const pidProfile_t *pidProfile)
 327 {
 328     for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 329         pidCoefficient[axis].Kp = PTERM_SCALE * pidProfile->pid[axis].P;
 330         pidCoefficient[axis].Ki = ITERM_SCALE * pidProfile->pid[axis].I;
 331         pidCoefficient[axis].Kd = DTERM_SCALE * pidProfile->pid[axis].D;
 332     }
 333
 334     dtermSetpointWeight = pidProfile->dtermSetpointWeight / 127.0f;
 335     if (pidProfile->setpointRelaxRatio == 0) {
 336         relaxFactor = 0;
 337     } else {
 338         relaxFactor = 100.0f / pidProfile->setpointRelaxRatio;
 339     }
 340     levelGain = pidProfile->pid[PID_LEVEL].P / 10.0f;
 341     horizonGain = pidProfile->pid[PID_LEVEL].I / 10.0f;
 342     horizonTransition = (float)pidProfile->pid[PID_LEVEL].D;
 343     horizonTiltExpertMode = pidProfile->horizon_tilt_expert_mode;
 344     horizonCutoffDegrees = (175 - pidProfile->horizon_tilt_effect) * 1.8f;
 345     horizonFactorRatio = (100 - pidProfile->horizon_tilt_effect) * 0.01f;
 346     maxVelocity[FD_ROLL] = maxVelocity[FD_PITCH] = pidProfile->rateAccelLimit * 100 * dT;
 347     maxVelocity[FD_YAW] = pidProfile->yawRateAccelLimit * 100 * dT;
 348     const float ITermWindupPoint = (float)pidProfile->itermWindupPointPercent / 100.0f;
 349     ITermWindupPointInv = 1.0f / (1.0f - ITermWindupPoint);
 350     crashTimeLimitUs = pidProfile->crash_time * 1000;
 351     crashTimeDelayUs = pidProfile->crash_delay * 1000;
 352     crashRecoveryAngleDeciDegrees = pidProfile->crash_recovery_angle * 10;
 353     crashRecoveryRate = pidProfile->crash_recovery_rate;
 354     crashGyroThreshold = pidProfile->crash_gthreshold;
 355     crashDtermThreshold = pidProfile->crash_dthreshold;
 356     crashSetpointThreshold = pidProfile->crash_setpoint_threshold;
 357     crashLimitYaw = pidProfile->crash_limit_yaw;
 358     itermLimit = pidProfile->itermLimit;
 359     throttleBoost = pidProfile->throttle_boost * 0.1f;
 360     itermRotation = pidProfile->iterm_rotation;
 361     smartFeedforward = pidProfile->smart_feedforward;
 362     itermRelax = pidProfile->iterm_relax;
 363     itermRelaxCutoffLow = pidProfile->iterm_relax_cutoff_low;
 364     itermRelaxCutoffHigh = pidProfile->iterm_relax_cutoff_high;
 365 }
 366
 367 void pidInit(const pidProfile_t *pidProfile)
 368 {
 369     pidSetTargetLooptime(gyro.targetLooptime * pidConfig()->pid_process_denom); // Initialize pid looptime
 370     pidInitFilters(pidProfile);
 371     pidInitConfig(pidProfile);
 372 }
 373
 374
 375 void pidCopyProfile(uint8_t dstPidProfileIndex, uint8_t srcPidProfileIndex)
 376 {
 377     if ((dstPidProfileIndex < MAX_PROFILE_COUNT-1 && srcPidProfileIndex < MAX_PROFILE_COUNT-1)
 378         && dstPidProfileIndex != srcPidProfileIndex
 379     ) {
 380         memcpy(pidProfilesMutable(dstPidProfileIndex), pidProfilesMutable(srcPidProfileIndex), sizeof(pidProfile_t));
 381     }
 382 }
 383
 384 // calculates strength of horizon leveling; 0 = none, 1.0 = most leveling
 385 static float calcHorizonLevelStrength(void)
 386 {
 387     // start with 1.0 at center stick, 0.0 at max stick deflection:
 388     float horizonLevelStrength = 1.0f - MAX(getRcDeflectionAbs(FD_ROLL), getRcDeflectionAbs(FD_PITCH));
 389
 390     // 0 at level, 90 at vertical, 180 at inverted (degrees):
 391     const float currentInclination = MAX(ABS(attitude.values.roll), ABS(attitude.values.pitch)) / 10.0f;
 392
 393     // horizonTiltExpertMode:  0 = leveling always active when sticks centered,
 394     //                         1 = leveling can be totally off when inverted
 395     if (horizonTiltExpertMode) {
 396         if (horizonTransition > 0 && horizonCutoffDegrees > 0) {
 397                     // if d_level > 0 and horizonTiltEffect < 175
 398             // horizonCutoffDegrees: 0 to 125 => 270 to 90 (represents where leveling goes to zero)
 399             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 400             //  for larger inclinations; 0.0 at horizonCutoffDegrees value:
 401             const float inclinationLevelRatio = constrainf((horizonCutoffDegrees-currentInclination) / horizonCutoffDegrees, 0, 1);
 402             // apply configured horizon sensitivity:
 403                 // when stick is near center (horizonLevelStrength ~= 1.0)
 404                 //  H_sensitivity value has little effect,
 405                 // when stick is deflected (horizonLevelStrength near 0.0)
 406                 //  H_sensitivity value has more effect:
 407             horizonLevelStrength = (horizonLevelStrength - 1) * 100 / horizonTransition + 1;
 408             // apply inclination ratio, which may lower leveling
 409             //  to zero regardless of stick position:
 410             horizonLevelStrength *= inclinationLevelRatio;
 411         } else  { // d_level=0 or horizon_tilt_effect>=175 means no leveling
 412           horizonLevelStrength = 0;
 413         }
 414     } else { // horizon_tilt_expert_mode = 0 (leveling always active when sticks centered)
 415         float sensitFact;
 416         if (horizonFactorRatio < 1.01f) { // if horizonTiltEffect > 0
 417             // horizonFactorRatio: 1.0 to 0.0 (larger means more leveling)
 418             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 419             //  for larger inclinations, goes to 1.0 at inclination==level:
 420             const float inclinationLevelRatio = (180-currentInclination)/180 * (1.0f-horizonFactorRatio) + horizonFactorRatio;
 421             // apply ratio to configured horizon sensitivity:
 422             sensitFact = horizonTransition * inclinationLevelRatio;
 423         } else { // horizonTiltEffect=0 for "old" functionality
 424             sensitFact = horizonTransition;
 425         }
 426
 427         if (sensitFact <= 0) {           // zero means no leveling
 428             horizonLevelStrength = 0;
 429         } else {
 430             // when stick is near center (horizonLevelStrength ~= 1.0)
 431             //  sensitFact value has little effect,
 432             // when stick is deflected (horizonLevelStrength near 0.0)
 433             //  sensitFact value has more effect:
 434             horizonLevelStrength = ((horizonLevelStrength - 1) * (100 / sensitFact)) + 1;
 435         }
 436     }
 437     return constrainf(horizonLevelStrength, 0, 1);
 438 }
 439
 440 static float pidLevel(int axis, const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, float currentPidSetpoint) {
 441     // calculate error angle and limit the angle to the max inclination
 442     // rcDeflection is in range [-1.0, 1.0]
 443     float angle = pidProfile->levelAngleLimit * getRcDeflection(axis);
 444 #ifdef USE_GPS_RESCUE
 445     angle += gpsRescueAngle[axis] / 100; // ANGLE IS IN CENTIDEGREES
 446 #endif
 447     angle = constrainf(angle, -pidProfile->levelAngleLimit, pidProfile->levelAngleLimit);
 448     const float errorAngle = angle - ((attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f);
 449     if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) {
 450         // ANGLE mode - control is angle based
 451         currentPidSetpoint = errorAngle * levelGain;
 452     } else {
 453         // HORIZON mode - mix of ANGLE and ACRO modes
 454         // mix in errorAngle to currentPidSetpoint to add a little auto-level feel
 455         const float horizonLevelStrength = calcHorizonLevelStrength();
 456         currentPidSetpoint = currentPidSetpoint + (errorAngle * horizonGain * horizonLevelStrength);
 457     }
 458     return currentPidSetpoint;
 459 }
 460
 461 static float accelerationLimit(int axis, float currentPidSetpoint)
 462 {
 463     static float previousSetpoint[3];
 464     const float currentVelocity = currentPidSetpoint - previousSetpoint[axis];
 465
 466     if (ABS(currentVelocity) > maxVelocity[axis]) {
 467         currentPidSetpoint = (currentVelocity > 0) ? previousSetpoint[axis] + maxVelocity[axis] : previousSetpoint[axis] - maxVelocity[axis];
 468     }
 469
 470     previousSetpoint[axis] = currentPidSetpoint;
 471     return currentPidSetpoint;
 472 }
 473
 474 static timeUs_t crashDetectedAtUs;
 475
 476 static void handleCrashRecovery(
 477     const pidCrashRecovery_e crash_recovery, const rollAndPitchTrims_t *angleTrim,
 478     const int axis, const timeUs_t currentTimeUs, const float gyroRate, float *currentPidSetpoint, float *errorRate)
 479 {
 480     if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeDelayUs) {
 481         if (crash_recovery == PID_CRASH_RECOVERY_BEEP) {
 482             BEEP_ON;
 483         }
 484         if (axis == FD_YAW) {
 485             *errorRate = constrainf(*errorRate, -crashLimitYaw, crashLimitYaw);
 486         } else {
 487             // on roll and pitch axes calculate currentPidSetpoint and errorRate to level the aircraft to recover from crash
 488             if (sensors(SENSOR_ACC)) {
 489                 // errorAngle is deviation from horizontal
 490                 const float errorAngle =  -(attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 491                 *currentPidSetpoint = errorAngle * levelGain;
 492                 *errorRate = *currentPidSetpoint - gyroRate;
 493             }
 494         }
 495         // reset ITerm, since accumulated error before crash is now meaningless
 496         // and ITerm windup during crash recovery can be extreme, especially on yaw axis
 497         pidData[axis].I = 0.0f;
 498         if (cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeLimitUs
 499             || (getMotorMixRange() < 1.0f
 500                    && ABS(gyro.gyroADCf[FD_ROLL]) < crashRecoveryRate
 501                    && ABS(gyro.gyroADCf[FD_PITCH]) < crashRecoveryRate
 502                    && ABS(gyro.gyroADCf[FD_YAW]) < crashRecoveryRate)) {
 503             if (sensors(SENSOR_ACC)) {
 504                 // check aircraft nearly level
 505                 if (ABS(attitude.raw[FD_ROLL] - angleTrim->raw[FD_ROLL]) < crashRecoveryAngleDeciDegrees
 506                    && ABS(attitude.raw[FD_PITCH] - angleTrim->raw[FD_PITCH]) < crashRecoveryAngleDeciDegrees) {
 507                     inCrashRecoveryMode = false;
 508                     BEEP_OFF;
 509                 }
 510             } else {
 511                 inCrashRecoveryMode = false;
 512                 BEEP_OFF;
 513             }
 514         }
 515     }
 516 }
 517
 518 static void detectAndSetCrashRecovery(
 519     const pidCrashRecovery_e crash_recovery, const int axis,
 520     const timeUs_t currentTimeUs, const float delta, const float errorRate)
 521 {
 522     // if crash recovery is on and accelerometer enabled and there is no gyro overflow, then check for a crash
 523     // no point in trying to recover if the crash is so severe that the gyro overflows
 524     if ((crash_recovery || FLIGHT_MODE(GPS_RESCUE_MODE)) && !gyroOverflowDetected()) {
 525         if (ARMING_FLAG(ARMED)) {
 526             if (getMotorMixRange() >= 1.0f && !inCrashRecoveryMode
 527                 && ABS(delta) > crashDtermThreshold
 528                 && ABS(errorRate) > crashGyroThreshold
 529                 && ABS(getSetpointRate(axis)) < crashSetpointThreshold) {
 530                 inCrashRecoveryMode = true;
 531                 crashDetectedAtUs = currentTimeUs;
 532             }
 533             if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) < crashTimeDelayUs && (ABS(errorRate) < crashGyroThreshold
 534                 || ABS(getSetpointRate(axis)) > crashSetpointThreshold)) {
 535                 inCrashRecoveryMode = false;
 536                 BEEP_OFF;
 537             }
 538         } else if (inCrashRecoveryMode) {
 539             inCrashRecoveryMode = false;
 540             BEEP_OFF;
 541         }
 542     }
 543 }
 544
 545 static void handleItermRotation()
 546 {
 547     // rotate old I to the new coordinate system
 548     const float gyroToAngle = dT * RAD;
 549     for (int i = FD_ROLL; i <= FD_YAW; i++) {
 550         int i_1 = (i + 1) % 3;
 551         int i_2 = (i + 2) % 3;
 552         float angle = gyro.gyroADCf[i] * gyroToAngle;
 553         float newPID_I_i_1 = pidData[i_1].I + pidData[i_2].I * angle;
 554         pidData[i_2].I -= pidData[i_1].I * angle;
 555         pidData[i_1].I = newPID_I_i_1;
 556     }
 557 }
 558
 559 // Betaflight pid controller, which will be maintained in the future with additional features specialised for current (mini) multirotor usage.
 560 // Based on 2DOF reference design (matlab)
 561 void FAST_CODE pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, timeUs_t currentTimeUs)
 562 {
 563     static float previousGyroRateDterm[2];
 564     static float previousPidSetpoint[2];
 565
 566     const float tpaFactor = getThrottlePIDAttenuation();
 567     const float motorMixRange = getMotorMixRange();
 568
 569 #ifdef USE_YAW_SPIN_RECOVERY
 570     const bool yawSpinActive = gyroYawSpinDetected();
 571 #endif
 572
 573     // Dynamic i component,
 574     // gradually scale back integration when above windup point
 575     const float dynCi = MIN((1.0f - motorMixRange) * ITermWindupPointInv, 1.0f) * dT * itermAccelerator;
 576
 577     // Dynamic d component, enable 2-DOF PID controller only for rate mode
 578     const float dynCd = flightModeFlags ? 0.0f : dtermSetpointWeight;
 579
 580     // Precalculate gyro deta for D-term here, this allows loop unrolling
 581     float gyroRateDterm[2];
 582     for (int axis = FD_ROLL; axis < FD_YAW; ++axis) {
 583         gyroRateDterm[axis] = dtermNotchApplyFn((filter_t *) &dtermNotch[axis], gyro.gyroADCf[axis]);
 584         gyroRateDterm[axis] = dtermLowpassApplyFn((filter_t *) &dtermLowpass[axis], gyroRateDterm[axis]);
 585         gyroRateDterm[axis] = dtermLowpass2ApplyFn((filter_t *) &dtermLowpass2[axis], gyroRateDterm[axis]);
 586     }
 587
 588     if (itermRotation) {
 589         handleItermRotation();
 590     }
 591
 592     // ----------PID controller----------
 593     for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 594         float currentPidSetpoint = getSetpointRate(axis);
 595         if (maxVelocity[axis]) {
 596             currentPidSetpoint = accelerationLimit(axis, currentPidSetpoint);
 597         }
 598         // Yaw control is GYRO based, direct sticks control is applied to rate PID
 599         if ((FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) && axis != YAW) {
 600             currentPidSetpoint = pidLevel(axis, pidProfile, angleTrim, currentPidSetpoint);
 601         }
 602
 603         // Handle yaw spin recovery - zero the setpoint on yaw to aid in recovery
 604         // It's not necessary to zero the set points for R/P because the PIDs will be zeroed below
 605 #ifdef USE_YAW_SPIN_RECOVERY
 606         if ((axis == FD_YAW) && yawSpinActive) {
 607             currentPidSetpoint = 0.0f;
 608         }
 609 #endif // USE_YAW_SPIN_RECOVERY
 610
 611         // -----calculate error rate
 612         const float gyroRate = gyro.gyroADCf[axis]; // Process variable from gyro output in deg/sec
 613         float errorRate = currentPidSetpoint - gyroRate; // r - y
 614
 615         handleCrashRecovery(
 616             pidProfile->crash_recovery, angleTrim, axis, currentTimeUs, gyroRate,
 617             &currentPidSetpoint, &errorRate);
 618
 619         // --------low-level gyro-based PID based on 2DOF PID controller. ----------
 620         // 2-DOF PID controller with optional filter on derivative term.
 621         // b = 1 and only c (dtermSetpointWeight) can be tuned (amount derivative on measurement or error).
 622
 623         // -----calculate P component and add Dynamic Part based on stick input
 624         pidData[axis].P = pidCoefficient[axis].Kp * errorRate * tpaFactor;
 625         if (axis == FD_YAW) {
 626             pidData[axis].P = ptermYawLowpassApplyFn((filter_t *) &ptermYawLowpass, pidData[axis].P);
 627         }
 628
 629         // -----calculate I component
 630         float itermErrorRate;
 631         if (itermRelax) {
 632             const float gyroTargetHigh = pt1FilterApply(&windupLpf[axis][0], currentPidSetpoint);
 633             const float gyroTargetLow =  pt1FilterApply(&windupLpf[axis][1], currentPidSetpoint);
 634             DEBUG_SET(DEBUG_ITERM_RELAX, 0, gyroTargetHigh);
 635             DEBUG_SET(DEBUG_ITERM_RELAX, 1, gyroTargetLow);
 636             const float gmax = MAX(gyroTargetHigh, gyroTargetLow);
 637             const float gmin = MIN(gyroTargetHigh, gyroTargetLow);
 638             if (gyroRate >= gmin && gyroRate <= gmax)
 639                 itermErrorRate = 0.0f;
 640             else
 641                 itermErrorRate = (gyroRate > gmax ? gmax : gmin ) - gyroRate;
 642         }
 643         else itermErrorRate = errorRate;
 644
 645         const float ITerm = pidData[axis].I;
 646         const float ITermNew = constrainf(ITerm + pidCoefficient[axis].Ki * itermErrorRate * dynCi, -itermLimit, itermLimit);
 647         const bool outputSaturated = mixerIsOutputSaturated(axis, errorRate);
 648         if (outputSaturated == false || ABS(ITermNew) < ABS(ITerm)) {
 649             // Only increase ITerm if output is not saturated
 650             pidData[axis].I = ITermNew;
 651         }
 652
 653         // -----calculate D component
 654         if (axis != FD_YAW) {
 655             // no transition if relaxFactor == 0
 656             float transition = relaxFactor > 0 ? MIN(1.f, getRcDeflectionAbs(axis) * relaxFactor) : 1;
 657
 658             // Divide rate change by dT to get differential (ie dr/dt).
 659             // dT is fixed and calculated from the target PID loop time
 660             // This is done to avoid DTerm spikes that occur with dynamically
 661             // calculated deltaT whenever another task causes the PID
 662             // loop execution to be delayed.
 663             const float delta =
 664                 - (gyroRateDterm[axis] - previousGyroRateDterm[axis]) / dT;
 665
 666             detectAndSetCrashRecovery(pidProfile->crash_recovery, axis, currentTimeUs, delta, errorRate);
 667
 668             pidData[axis].D = pidCoefficient[axis].Kd * delta * tpaFactor;
 669
 670             const float pidFeedForward =
 671                 pidCoefficient[axis].Kd * dynCd * transition *
 672                 (currentPidSetpoint - previousPidSetpoint[axis]) * tpaFactor / dT;
 673             bool addFeedforward = true;
 674             if (smartFeedforward) {
 675                 if (pidData[axis].P * pidFeedForward > 0) {
 676                     if (ABS(pidFeedForward) > ABS(pidData[axis].P)) {
 677                         pidData[axis].P = 0;
 678                     }
 679                     else {
 680                         addFeedforward = false;
 681                     }
 682                 }
 683             }
 684             if (addFeedforward) {
 685                 pidData[axis].D += pidFeedForward;
 686             }
 687             previousGyroRateDterm[axis] = gyroRateDterm[axis];
 688             previousPidSetpoint[axis] = currentPidSetpoint;
 689
 690 #ifdef USE_YAW_SPIN_RECOVERY
 691             if (yawSpinActive)  {
 692                 // zero PIDs on pitch and roll leaving yaw P to correct spin
 693                 pidData[axis].P = 0;
 694                 pidData[axis].I = 0;
 695                 pidData[axis].D = 0;
 696             }
 697 #endif // USE_YAW_SPIN_RECOVERY
 698         }
 699     }
 700
 701     // calculating the PID sum
 702     pidData[FD_ROLL].Sum = pidData[FD_ROLL].P + pidData[FD_ROLL].I + pidData[FD_ROLL].D;
 703     pidData[FD_PITCH].Sum = pidData[FD_PITCH].P + pidData[FD_PITCH].I + pidData[FD_PITCH].D;
 704
 705 #ifdef USE_YAW_SPIN_RECOVERY
 706     if (yawSpinActive) {
 707     // yaw P alone to correct spin
 708         pidData[FD_YAW].I = 0;
 709     }
 710 #endif // USE_YAW_SPIN_RECOVERY
 711
 712     // YAW has no D
 713     pidData[FD_YAW].Sum = pidData[FD_YAW].P + pidData[FD_YAW].I;
 714
 715     // Disable PID control if at zero throttle or if gyro overflow detected
 716     // This may look very innefficient, but it is done on purpose to always show real CPU usage as in flight
 717     if (!pidStabilisationEnabled || gyroOverflowDetected()) {
 718         for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 719             pidData[axis].P = 0;
 720             pidData[axis].I = 0;
 721             pidData[axis].D = 0;
 722
 723             pidData[axis].Sum = 0;
 724         }
 725     }
 726 }
 727
 728 bool crashRecoveryModeActive(void)
 729 {
 730     return inCrashRecoveryMode;
 731 }