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 #ifdef USE_ACRO_TRAINER
  92 #define ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT 500.0f  // Max gyro rate for lookahead time scaling
  93 #define ACRO_TRAINER_SETPOINT_LIMIT       1000.0f // Limit the correcting setpoint
  94 #endif // USE_ACRO_TRAINER
  95
  96 PG_REGISTER_ARRAY_WITH_RESET_FN(pidProfile_t, MAX_PROFILE_COUNT, pidProfiles, PG_PID_PROFILE, 4);
  97
  98 void resetPidProfile(pidProfile_t *pidProfile)
  99 {
 100     RESET_CONFIG(pidProfile_t, pidProfile,
 101         .pid = {
 102             [PID_ROLL] =  { 40, 40, 30 },
 103             [PID_PITCH] = { 58, 50, 35 },
 104             [PID_YAW] =   { 70, 45, 20 },
 105             [PID_ALT] =   { 50, 0, 0 },
 106             [PID_POS] =   { 15, 0, 0 },     // POSHOLD_P * 100, POSHOLD_I * 100,
 107             [PID_POSR] =  { 34, 14, 53 },   // POSHOLD_RATE_P * 10, POSHOLD_RATE_I * 100, POSHOLD_RATE_D * 1000,
 108             [PID_NAVR] =  { 25, 33, 83 },   // NAV_P * 10, NAV_I * 100, NAV_D * 1000
 109             [PID_LEVEL] = { 50, 50, 75 },
 110             [PID_MAG] =   { 40, 0, 0 },
 111             [PID_VEL] =   { 55, 55, 75 }
 112         },
 113
 114         .pidSumLimit = PIDSUM_LIMIT,
 115         .pidSumLimitYaw = PIDSUM_LIMIT_YAW,
 116         .yaw_lowpass_hz = 0,
 117         .dterm_lowpass_hz = 100,    // filtering ON by default
 118         .dterm_lowpass2_hz = 0,     // second Dterm LPF OFF by default
 119         .dterm_notch_hz = 260,
 120         .dterm_notch_cutoff = 160,
 121         .dterm_filter_type = FILTER_BIQUAD,
 122         .itermWindupPointPercent = 50,
 123         .vbatPidCompensation = 0,
 124         .pidAtMinThrottle = PID_STABILISATION_ON,
 125         .levelAngleLimit = 55,
 126         .setpointRelaxRatio = 100,
 127         .dtermSetpointWeight = 0,
 128         .yawRateAccelLimit = 100,
 129         .rateAccelLimit = 0,
 130         .itermThrottleThreshold = 350,
 131         .itermAcceleratorGain = 1000,
 132         .crash_time = 500,          // ms
 133         .crash_delay = 0,           // ms
 134         .crash_recovery_angle = 10, // degrees
 135         .crash_recovery_rate = 100, // degrees/second
 136         .crash_dthreshold = 50,     // degrees/second/second
 137         .crash_gthreshold = 400,    // degrees/second
 138         .crash_setpoint_threshold = 350, // degrees/second
 139         .crash_recovery = PID_CRASH_RECOVERY_OFF, // off by default
 140         .horizon_tilt_effect = 75,
 141         .horizon_tilt_expert_mode = false,
 142         .crash_limit_yaw = 200,
 143         .itermLimit = 150,
 144         .throttle_boost = 0,
 145         .throttle_boost_cutoff = 15,
 146         .iterm_rotation = false,
 147         .smart_feedforward = false,
 148         .iterm_relax = ITERM_RELAX_OFF,
 149         .iterm_relax_cutoff_low = 3,
 150         .iterm_relax_cutoff_high = 30,
 151         .acro_trainer_angle_limit = 20,
 152         .acro_trainer_lookahead_ms = 50,
 153         .acro_trainer_debug_axis = FD_ROLL,
 154         .acro_trainer_gain = 75,
 155         .abs_control_gain = 0,
 156         .abs_control_limit = 90,
 157         .abs_control_error_limit = 20,
 158     );
 159 }
 160
 161 void pgResetFn_pidProfiles(pidProfile_t *pidProfiles)
 162 {
 163     for (int i = 0; i < MAX_PROFILE_COUNT; i++) {
 164         resetPidProfile(&pidProfiles[i]);
 165     }
 166 }
 167
 168 static void pidSetTargetLooptime(uint32_t pidLooptime)
 169 {
 170     targetPidLooptime = pidLooptime;
 171     dT = (float)targetPidLooptime * 0.000001f;
 172 }
 173
 174 static FAST_RAM float itermAccelerator = 1.0f;
 175
 176 void pidSetItermAccelerator(float newItermAccelerator)
 177 {
 178     itermAccelerator = newItermAccelerator;
 179 }
 180
 181 float pidItermAccelerator(void)
 182 {
 183     return itermAccelerator;
 184 }
 185
 186 void pidStabilisationState(pidStabilisationState_e pidControllerState)
 187 {
 188     pidStabilisationEnabled = (pidControllerState == PID_STABILISATION_ON) ? true : false;
 189 }
 190
 191 const angle_index_t rcAliasToAngleIndexMap[] = { AI_ROLL, AI_PITCH };
 192
 193 typedef union dtermLowpass_u {
 194     pt1Filter_t pt1Filter;
 195     biquadFilter_t biquadFilter;
 196 } dtermLowpass_t;
 197
 198 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermNotchApplyFn;
 199 static FAST_RAM_ZERO_INIT biquadFilter_t dtermNotch[2];
 200 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpassApplyFn;
 201 static FAST_RAM_ZERO_INIT dtermLowpass_t dtermLowpass[2];
 202 static FAST_RAM_ZERO_INIT filterApplyFnPtr dtermLowpass2ApplyFn;
 203 static FAST_RAM_ZERO_INIT pt1Filter_t dtermLowpass2[2];
 204 static FAST_RAM_ZERO_INIT filterApplyFnPtr ptermYawLowpassApplyFn;
 205 static FAST_RAM_ZERO_INIT pt1Filter_t ptermYawLowpass;
 206 #if defined(USE_ITERM_RELAX)
 207 static FAST_RAM_ZERO_INIT pt1Filter_t windupLpf[XYZ_AXIS_COUNT][2];
 208 static FAST_RAM_ZERO_INIT uint8_t itermRelax;
 209 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoffLow;
 210 static FAST_RAM_ZERO_INIT uint8_t itermRelaxCutoffHigh;
 211 #endif
 212
 213 void pidInitFilters(const pidProfile_t *pidProfile)
 214 {
 215     BUILD_BUG_ON(FD_YAW != 2); // only setting up Dterm filters on roll and pitch axes, so ensure yaw axis is 2
 216
 217     if (targetPidLooptime == 0) {
 218         // no looptime set, so set all the filters to null
 219         dtermNotchApplyFn = nullFilterApply;
 220         dtermLowpassApplyFn = nullFilterApply;
 221         ptermYawLowpassApplyFn = nullFilterApply;
 222         return;
 223     }
 224
 225     const uint32_t pidFrequencyNyquist = (1.0f / dT) / 2; // No rounding needed
 226
 227     uint16_t dTermNotchHz;
 228     if (pidProfile->dterm_notch_hz <= pidFrequencyNyquist) {
 229         dTermNotchHz = pidProfile->dterm_notch_hz;
 230     } else {
 231         if (pidProfile->dterm_notch_cutoff < pidFrequencyNyquist) {
 232             dTermNotchHz = pidFrequencyNyquist;
 233         } else {
 234             dTermNotchHz = 0;
 235         }
 236     }
 237
 238     if (dTermNotchHz != 0 && pidProfile->dterm_notch_cutoff != 0) {
 239         dtermNotchApplyFn = (filterApplyFnPtr)biquadFilterApply;
 240         const float notchQ = filterGetNotchQ(dTermNotchHz, pidProfile->dterm_notch_cutoff);
 241         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 242             biquadFilterInit(&dtermNotch[axis], dTermNotchHz, targetPidLooptime, notchQ, FILTER_NOTCH);
 243         }
 244     } else {
 245         dtermNotchApplyFn = nullFilterApply;
 246     }
 247
 248     //2nd Dterm Lowpass Filter
 249     if (pidProfile->dterm_lowpass2_hz == 0 || pidProfile->dterm_lowpass2_hz > pidFrequencyNyquist) {
 250         dtermLowpass2ApplyFn = nullFilterApply;
 251     } else {
 252         dtermLowpass2ApplyFn = (filterApplyFnPtr)pt1FilterApply;
 253         for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 254             pt1FilterInit(&dtermLowpass2[axis], pt1FilterGain(pidProfile->dterm_lowpass2_hz, dT));
 255         }
 256     }
 257
 258     if (pidProfile->dterm_lowpass_hz == 0 || pidProfile->dterm_lowpass_hz > pidFrequencyNyquist) {
 259         dtermLowpassApplyFn = nullFilterApply;
 260     } else {
 261         switch (pidProfile->dterm_filter_type) {
 262         default:
 263             dtermLowpassApplyFn = nullFilterApply;
 264             break;
 265         case FILTER_PT1:
 266             dtermLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 267             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 268                 pt1FilterInit(&dtermLowpass[axis].pt1Filter, pt1FilterGain(pidProfile->dterm_lowpass_hz, dT));
 269             }
 270             break;
 271         case FILTER_BIQUAD:
 272             dtermLowpassApplyFn = (filterApplyFnPtr)biquadFilterApply;
 273             for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
 274                 biquadFilterInitLPF(&dtermLowpass[axis].biquadFilter, pidProfile->dterm_lowpass_hz, targetPidLooptime);
 275             }
 276             break;
 277         }
 278     }
 279
 280     if (pidProfile->yaw_lowpass_hz == 0 || pidProfile->yaw_lowpass_hz > pidFrequencyNyquist) {
 281         ptermYawLowpassApplyFn = nullFilterApply;
 282     } else {
 283         ptermYawLowpassApplyFn = (filterApplyFnPtr)pt1FilterApply;
 284         pt1FilterInit(&ptermYawLowpass, pt1FilterGain(pidProfile->yaw_lowpass_hz, dT));
 285     }
 286
 287     pt1FilterInit(&throttleLpf, pt1FilterGain(pidProfile->throttle_boost_cutoff, dT));
 288 #if defined(USE_ITERM_RELAX)
 289     if (itermRelax) {
 290         for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 291             pt1FilterInit(&windupLpf[i][0], pt1FilterGain(itermRelaxCutoffLow, dT));
 292             pt1FilterInit(&windupLpf[i][1], pt1FilterGain(itermRelaxCutoffHigh, dT));
 293         }
 294     }
 295 #endif
 296 }
 297
 298 typedef struct pidCoefficient_s {
 299     float Kp;
 300     float Ki;
 301     float Kd;
 302 } pidCoefficient_t;
 303
 304 static FAST_RAM_ZERO_INIT pidCoefficient_t pidCoefficient[3];
 305 static FAST_RAM_ZERO_INIT float maxVelocity[3];
 306 static FAST_RAM_ZERO_INIT float relaxFactor;
 307 static FAST_RAM_ZERO_INIT float dtermSetpointWeight;
 308 static FAST_RAM_ZERO_INIT float levelGain, horizonGain, horizonTransition, horizonCutoffDegrees, horizonFactorRatio;
 309 static FAST_RAM_ZERO_INIT float ITermWindupPointInv;
 310 static FAST_RAM_ZERO_INIT uint8_t horizonTiltExpertMode;
 311 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeLimitUs;
 312 static FAST_RAM_ZERO_INIT timeDelta_t crashTimeDelayUs;
 313 static FAST_RAM_ZERO_INIT int32_t crashRecoveryAngleDeciDegrees;
 314 static FAST_RAM_ZERO_INIT float crashRecoveryRate;
 315 static FAST_RAM_ZERO_INIT float crashDtermThreshold;
 316 static FAST_RAM_ZERO_INIT float crashGyroThreshold;
 317 static FAST_RAM_ZERO_INIT float crashSetpointThreshold;
 318 static FAST_RAM_ZERO_INIT float crashLimitYaw;
 319 static FAST_RAM_ZERO_INIT float itermLimit;
 320 FAST_RAM_ZERO_INIT float throttleBoost;
 321 pt1Filter_t throttleLpf;
 322 static FAST_RAM_ZERO_INIT bool itermRotation;
 323
 324 #if defined(USE_SMART_FEEDFORWARD)
 325 static FAST_RAM_ZERO_INIT bool smartFeedforward;
 326 #endif
 327 #if defined(USE_ABSOLUTE_CONTROL)
 328 static FAST_RAM_ZERO_INIT float axisError[XYZ_AXIS_COUNT];
 329 static FAST_RAM_ZERO_INIT float acGain;
 330 static FAST_RAM_ZERO_INIT float acLimit;
 331 static FAST_RAM_ZERO_INIT float acErrorLimit;
 332 #endif
 333
 334 void pidResetITerm(void)
 335 {
 336     for (int axis = 0; axis < 3; axis++) {
 337         pidData[axis].I = 0.0f;
 338 #if defined(USE_ABSOLUTE_CONTROL)
 339         axisError[axis] = 0.0f;
 340 #endif
 341     }
 342 }
 343
 344 #ifdef USE_ACRO_TRAINER
 345 static FAST_RAM_ZERO_INIT float acroTrainerAngleLimit;
 346 static FAST_RAM_ZERO_INIT float acroTrainerLookaheadTime;
 347 static FAST_RAM_ZERO_INIT uint8_t acroTrainerDebugAxis;
 348 static FAST_RAM_ZERO_INIT bool acroTrainerActive;
 349 static FAST_RAM_ZERO_INIT int acroTrainerAxisState[2];  // only need roll and pitch
 350 static FAST_RAM_ZERO_INIT float acroTrainerGain;
 351 #endif // USE_ACRO_TRAINER
 352
 353 void pidInitConfig(const pidProfile_t *pidProfile)
 354 {
 355     for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
 356         pidCoefficient[axis].Kp = PTERM_SCALE * pidProfile->pid[axis].P;
 357         pidCoefficient[axis].Ki = ITERM_SCALE * pidProfile->pid[axis].I;
 358         pidCoefficient[axis].Kd = DTERM_SCALE * pidProfile->pid[axis].D;
 359     }
 360
 361     dtermSetpointWeight = pidProfile->dtermSetpointWeight / 127.0f;
 362     if (pidProfile->setpointRelaxRatio == 0) {
 363         relaxFactor = 0;
 364     } else {
 365         relaxFactor = 100.0f / pidProfile->setpointRelaxRatio;
 366     }
 367     levelGain = pidProfile->pid[PID_LEVEL].P / 10.0f;
 368     horizonGain = pidProfile->pid[PID_LEVEL].I / 10.0f;
 369     horizonTransition = (float)pidProfile->pid[PID_LEVEL].D;
 370     horizonTiltExpertMode = pidProfile->horizon_tilt_expert_mode;
 371     horizonCutoffDegrees = (175 - pidProfile->horizon_tilt_effect) * 1.8f;
 372     horizonFactorRatio = (100 - pidProfile->horizon_tilt_effect) * 0.01f;
 373     maxVelocity[FD_ROLL] = maxVelocity[FD_PITCH] = pidProfile->rateAccelLimit * 100 * dT;
 374     maxVelocity[FD_YAW] = pidProfile->yawRateAccelLimit * 100 * dT;
 375     const float ITermWindupPoint = (float)pidProfile->itermWindupPointPercent / 100.0f;
 376     ITermWindupPointInv = 1.0f / (1.0f - ITermWindupPoint);
 377     crashTimeLimitUs = pidProfile->crash_time * 1000;
 378     crashTimeDelayUs = pidProfile->crash_delay * 1000;
 379     crashRecoveryAngleDeciDegrees = pidProfile->crash_recovery_angle * 10;
 380     crashRecoveryRate = pidProfile->crash_recovery_rate;
 381     crashGyroThreshold = pidProfile->crash_gthreshold;
 382     crashDtermThreshold = pidProfile->crash_dthreshold;
 383     crashSetpointThreshold = pidProfile->crash_setpoint_threshold;
 384     crashLimitYaw = pidProfile->crash_limit_yaw;
 385     itermLimit = pidProfile->itermLimit;
 386     throttleBoost = pidProfile->throttle_boost * 0.1f;
 387     itermRotation = pidProfile->iterm_rotation;
 388 #if defined(USE_SMART_FEEDFORWARD)
 389     smartFeedforward = pidProfile->smart_feedforward;
 390 #endif
 391 #if defined(USE_ITERM_RELAX)
 392     itermRelax = pidProfile->iterm_relax;
 393     itermRelaxCutoffLow = pidProfile->iterm_relax_cutoff_low;
 394     itermRelaxCutoffHigh = pidProfile->iterm_relax_cutoff_high;
 395 #endif
 396
 397 #ifdef USE_ACRO_TRAINER
 398     acroTrainerAngleLimit = pidProfile->acro_trainer_angle_limit;
 399     acroTrainerLookaheadTime = (float)pidProfile->acro_trainer_lookahead_ms / 1000.0f;
 400     acroTrainerDebugAxis = pidProfile->acro_trainer_debug_axis;
 401     acroTrainerGain = (float)pidProfile->acro_trainer_gain / 10.0f;
 402 #endif // USE_ACRO_TRAINER
 403
 404 #if defined(USE_ABSOLUTE_CONTROL)
 405     acGain = (float)pidProfile->abs_control_gain;
 406     acLimit = (float)pidProfile->abs_control_limit;
 407     acErrorLimit = (float)pidProfile->abs_control_error_limit;
 408 #endif
 409 }
 410
 411 void pidInit(const pidProfile_t *pidProfile)
 412 {
 413     pidSetTargetLooptime(gyro.targetLooptime * pidConfig()->pid_process_denom); // Initialize pid looptime
 414     pidInitFilters(pidProfile);
 415     pidInitConfig(pidProfile);
 416 }
 417
 418 #ifdef USE_ACRO_TRAINER
 419 void pidAcroTrainerInit(void)
 420 {
 421     acroTrainerAxisState[FD_ROLL] = 0;
 422     acroTrainerAxisState[FD_PITCH] = 0;
 423 }
 424 #endif // USE_ACRO_TRAINER
 425
 426 void pidCopyProfile(uint8_t dstPidProfileIndex, uint8_t srcPidProfileIndex)
 427 {
 428     if ((dstPidProfileIndex < MAX_PROFILE_COUNT-1 && srcPidProfileIndex < MAX_PROFILE_COUNT-1)
 429         && dstPidProfileIndex != srcPidProfileIndex
 430     ) {
 431         memcpy(pidProfilesMutable(dstPidProfileIndex), pidProfilesMutable(srcPidProfileIndex), sizeof(pidProfile_t));
 432     }
 433 }
 434
 435 // calculates strength of horizon leveling; 0 = none, 1.0 = most leveling
 436 static float calcHorizonLevelStrength(void)
 437 {
 438     // start with 1.0 at center stick, 0.0 at max stick deflection:
 439     float horizonLevelStrength = 1.0f - MAX(getRcDeflectionAbs(FD_ROLL), getRcDeflectionAbs(FD_PITCH));
 440
 441     // 0 at level, 90 at vertical, 180 at inverted (degrees):
 442     const float currentInclination = MAX(ABS(attitude.values.roll), ABS(attitude.values.pitch)) / 10.0f;
 443
 444     // horizonTiltExpertMode:  0 = leveling always active when sticks centered,
 445     //                         1 = leveling can be totally off when inverted
 446     if (horizonTiltExpertMode) {
 447         if (horizonTransition > 0 && horizonCutoffDegrees > 0) {
 448                     // if d_level > 0 and horizonTiltEffect < 175
 449             // horizonCutoffDegrees: 0 to 125 => 270 to 90 (represents where leveling goes to zero)
 450             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 451             //  for larger inclinations; 0.0 at horizonCutoffDegrees value:
 452             const float inclinationLevelRatio = constrainf((horizonCutoffDegrees-currentInclination) / horizonCutoffDegrees, 0, 1);
 453             // apply configured horizon sensitivity:
 454                 // when stick is near center (horizonLevelStrength ~= 1.0)
 455                 //  H_sensitivity value has little effect,
 456                 // when stick is deflected (horizonLevelStrength near 0.0)
 457                 //  H_sensitivity value has more effect:
 458             horizonLevelStrength = (horizonLevelStrength - 1) * 100 / horizonTransition + 1;
 459             // apply inclination ratio, which may lower leveling
 460             //  to zero regardless of stick position:
 461             horizonLevelStrength *= inclinationLevelRatio;
 462         } else  { // d_level=0 or horizon_tilt_effect>=175 means no leveling
 463           horizonLevelStrength = 0;
 464         }
 465     } else { // horizon_tilt_expert_mode = 0 (leveling always active when sticks centered)
 466         float sensitFact;
 467         if (horizonFactorRatio < 1.01f) { // if horizonTiltEffect > 0
 468             // horizonFactorRatio: 1.0 to 0.0 (larger means more leveling)
 469             // inclinationLevelRatio (0.0 to 1.0) is smaller (less leveling)
 470             //  for larger inclinations, goes to 1.0 at inclination==level:
 471             const float inclinationLevelRatio = (180-currentInclination)/180 * (1.0f-horizonFactorRatio) + horizonFactorRatio;
 472             // apply ratio to configured horizon sensitivity:
 473             sensitFact = horizonTransition * inclinationLevelRatio;
 474         } else { // horizonTiltEffect=0 for "old" functionality
 475             sensitFact = horizonTransition;
 476         }
 477
 478         if (sensitFact <= 0) {           // zero means no leveling
 479             horizonLevelStrength = 0;
 480         } else {
 481             // when stick is near center (horizonLevelStrength ~= 1.0)
 482             //  sensitFact value has little effect,
 483             // when stick is deflected (horizonLevelStrength near 0.0)
 484             //  sensitFact value has more effect:
 485             horizonLevelStrength = ((horizonLevelStrength - 1) * (100 / sensitFact)) + 1;
 486         }
 487     }
 488     return constrainf(horizonLevelStrength, 0, 1);
 489 }
 490
 491 static float pidLevel(int axis, const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, float currentPidSetpoint) {
 492     // calculate error angle and limit the angle to the max inclination
 493     // rcDeflection is in range [-1.0, 1.0]
 494     float angle = pidProfile->levelAngleLimit * getRcDeflection(axis);
 495 #ifdef USE_GPS_RESCUE
 496     angle += gpsRescueAngle[axis] / 100; // ANGLE IS IN CENTIDEGREES
 497 #endif
 498     angle = constrainf(angle, -pidProfile->levelAngleLimit, pidProfile->levelAngleLimit);
 499     const float errorAngle = angle - ((attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f);
 500     if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) {
 501         // ANGLE mode - control is angle based
 502         currentPidSetpoint = errorAngle * levelGain;
 503     } else {
 504         // HORIZON mode - mix of ANGLE and ACRO modes
 505         // mix in errorAngle to currentPidSetpoint to add a little auto-level feel
 506         const float horizonLevelStrength = calcHorizonLevelStrength();
 507         currentPidSetpoint = currentPidSetpoint + (errorAngle * horizonGain * horizonLevelStrength);
 508     }
 509     return currentPidSetpoint;
 510 }
 511
 512 static float accelerationLimit(int axis, float currentPidSetpoint)
 513 {
 514     static float previousSetpoint[3];
 515     const float currentVelocity = currentPidSetpoint - previousSetpoint[axis];
 516
 517     if (ABS(currentVelocity) > maxVelocity[axis]) {
 518         currentPidSetpoint = (currentVelocity > 0) ? previousSetpoint[axis] + maxVelocity[axis] : previousSetpoint[axis] - maxVelocity[axis];
 519     }
 520
 521     previousSetpoint[axis] = currentPidSetpoint;
 522     return currentPidSetpoint;
 523 }
 524
 525 static timeUs_t crashDetectedAtUs;
 526
 527 static void handleCrashRecovery(
 528     const pidCrashRecovery_e crash_recovery, const rollAndPitchTrims_t *angleTrim,
 529     const int axis, const timeUs_t currentTimeUs, const float gyroRate, float *currentPidSetpoint, float *errorRate)
 530 {
 531     if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeDelayUs) {
 532         if (crash_recovery == PID_CRASH_RECOVERY_BEEP) {
 533             BEEP_ON;
 534         }
 535         if (axis == FD_YAW) {
 536             *errorRate = constrainf(*errorRate, -crashLimitYaw, crashLimitYaw);
 537         } else {
 538             // on roll and pitch axes calculate currentPidSetpoint and errorRate to level the aircraft to recover from crash
 539             if (sensors(SENSOR_ACC)) {
 540                 // errorAngle is deviation from horizontal
 541                 const float errorAngle =  -(attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 542                 *currentPidSetpoint = errorAngle * levelGain;
 543                 *errorRate = *currentPidSetpoint - gyroRate;
 544             }
 545         }
 546         // reset ITerm, since accumulated error before crash is now meaningless
 547         // and ITerm windup during crash recovery can be extreme, especially on yaw axis
 548         pidData[axis].I = 0.0f;
 549         if (cmpTimeUs(currentTimeUs, crashDetectedAtUs) > crashTimeLimitUs
 550             || (getMotorMixRange() < 1.0f
 551                    && ABS(gyro.gyroADCf[FD_ROLL]) < crashRecoveryRate
 552                    && ABS(gyro.gyroADCf[FD_PITCH]) < crashRecoveryRate
 553                    && ABS(gyro.gyroADCf[FD_YAW]) < crashRecoveryRate)) {
 554             if (sensors(SENSOR_ACC)) {
 555                 // check aircraft nearly level
 556                 if (ABS(attitude.raw[FD_ROLL] - angleTrim->raw[FD_ROLL]) < crashRecoveryAngleDeciDegrees
 557                    && ABS(attitude.raw[FD_PITCH] - angleTrim->raw[FD_PITCH]) < crashRecoveryAngleDeciDegrees) {
 558                     inCrashRecoveryMode = false;
 559                     BEEP_OFF;
 560                 }
 561             } else {
 562                 inCrashRecoveryMode = false;
 563                 BEEP_OFF;
 564             }
 565         }
 566     }
 567 }
 568
 569 static void detectAndSetCrashRecovery(
 570     const pidCrashRecovery_e crash_recovery, const int axis,
 571     const timeUs_t currentTimeUs, const float delta, const float errorRate)
 572 {
 573     // if crash recovery is on and accelerometer enabled and there is no gyro overflow, then check for a crash
 574     // no point in trying to recover if the crash is so severe that the gyro overflows
 575     if ((crash_recovery || FLIGHT_MODE(GPS_RESCUE_MODE)) && !gyroOverflowDetected()) {
 576         if (ARMING_FLAG(ARMED)) {
 577             if (getMotorMixRange() >= 1.0f && !inCrashRecoveryMode
 578                 && ABS(delta) > crashDtermThreshold
 579                 && ABS(errorRate) > crashGyroThreshold
 580                 && ABS(getSetpointRate(axis)) < crashSetpointThreshold) {
 581                 inCrashRecoveryMode = true;
 582                 crashDetectedAtUs = currentTimeUs;
 583             }
 584             if (inCrashRecoveryMode && cmpTimeUs(currentTimeUs, crashDetectedAtUs) < crashTimeDelayUs && (ABS(errorRate) < crashGyroThreshold
 585                 || ABS(getSetpointRate(axis)) > crashSetpointThreshold)) {
 586                 inCrashRecoveryMode = false;
 587                 BEEP_OFF;
 588             }
 589         } else if (inCrashRecoveryMode) {
 590             inCrashRecoveryMode = false;
 591             BEEP_OFF;
 592         }
 593     }
 594 }
 595
 596 static void rotateVector(float v[XYZ_AXIS_COUNT], float rotation[XYZ_AXIS_COUNT])
 597 {
 598     // rotate v around rotation vector rotation
 599     // rotation in radians, all elements must be small
 600     for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 601         int i_1 = (i + 1) % 3;
 602         int i_2 = (i + 2) % 3;
 603         float newV = v[i_1] + v[i_2] * rotation[i];
 604         v[i_2] -= v[i_1] * rotation[i];
 605         v[i_1] = newV;
 606     }
 607 }
 608
 609 static void rotateITermAndAxisError()
 610 {
 611     if (itermRotation
 612 #if defined(USE_ABSOLUTE_CONTROL)
 613         || acGain > 0
 614 #endif
 615         ) {
 616         const float gyroToAngle = dT * RAD;
 617         float rotationRads[3];
 618         for (int i = FD_ROLL; i <= FD_YAW; i++) {
 619             rotationRads[i] = gyro.gyroADCf[i] * gyroToAngle;
 620         }
 621 #if defined(USE_ABSOLUTE_CONTROL)
 622         if (acGain > 0) {
 623             rotateVector(axisError, rotationRads);
 624         }
 625 #endif
 626         if (itermRotation) {
 627             float v[3];
 628             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 629                 v[i] = pidData[i].I;
 630             }
 631             rotateVector(v, rotationRads );
 632             for (int i = 0; i < XYZ_AXIS_COUNT; i++) {
 633                 pidData[i].I = v[i];
 634             }
 635         }
 636     }
 637 }
 638
 639 #ifdef USE_ACRO_TRAINER
 640
 641 int acroTrainerSign(float x)
 642 {
 643     return x > 0 ? 1 : -1;
 644 }
 645
 646 // Acro Trainer - Manipulate the setPoint to limit axis angle while in acro mode
 647 // There are three states:
 648 // 1. Current angle has exceeded limit
 649 //    Apply correction to return to limit (similar to pidLevel)
 650 // 2. Future overflow has been projected based on current angle and gyro rate
 651 //    Manage the setPoint to control the gyro rate as the actual angle  approaches the limit (try to prevent overshoot)
 652 // 3. If no potential overflow is detected, then return the original setPoint
 653
 654 // Use the FAST_CODE_NOINLINE directive to avoid this code from being inlined into ITCM RAM. We accept the
 655 // performance decrease when Acro Trainer mode is active under the assumption that user is unlikely to be
 656 // expecting ultimate flight performance at very high loop rates when in this mode.
 657 static FAST_CODE_NOINLINE float applyAcroTrainer(int axis, const rollAndPitchTrims_t *angleTrim, float setPoint)
 658 {
 659     float ret = setPoint;
 660
 661     if (!FLIGHT_MODE(ANGLE_MODE) && !FLIGHT_MODE(HORIZON_MODE) && !FLIGHT_MODE(GPS_RESCUE_MODE)) {
 662         bool resetIterm = false;
 663         float projectedAngle = 0;
 664         const int setpointSign = acroTrainerSign(setPoint);
 665         const float currentAngle = (attitude.raw[axis] - angleTrim->raw[axis]) / 10.0f;
 666         const int angleSign = acroTrainerSign(currentAngle);
 667
 668         if ((acroTrainerAxisState[axis] != 0) && (acroTrainerAxisState[axis] != setpointSign)) {  // stick has reversed - stop limiting
 669             acroTrainerAxisState[axis] = 0;
 670         }
 671
 672         // Limit and correct the angle when it exceeds the limit
 673         if ((fabsf(currentAngle) > acroTrainerAngleLimit) && (acroTrainerAxisState[axis] == 0)) {
 674             if (angleSign == setpointSign) {
 675                 acroTrainerAxisState[axis] = angleSign;
 676                 resetIterm = true;
 677             }
 678         }
 679
 680         if (acroTrainerAxisState[axis] != 0) {
 681             ret = constrainf(((acroTrainerAngleLimit * angleSign) - currentAngle) * acroTrainerGain, -ACRO_TRAINER_SETPOINT_LIMIT, ACRO_TRAINER_SETPOINT_LIMIT);
 682         } else {
 683
 684         // Not currently over the limit so project the angle based on current angle and
 685         // gyro angular rate using a sliding window based on gyro rate (faster rotation means larger window.
 686         // If the projected angle exceeds the limit then apply limiting to minimize overshoot.
 687             // Calculate the lookahead window by scaling proportionally with gyro rate from 0-500dps
 688             float checkInterval = constrainf(fabsf(gyro.gyroADCf[axis]) / ACRO_TRAINER_LOOKAHEAD_RATE_LIMIT, 0.0f, 1.0f) * acroTrainerLookaheadTime;
 689             projectedAngle = (gyro.gyroADCf[axis] * checkInterval) + currentAngle;
 690             const int projectedAngleSign = acroTrainerSign(projectedAngle);
 691             if ((fabsf(projectedAngle) > acroTrainerAngleLimit) && (projectedAngleSign == setpointSign)) {
 692                 ret = ((acroTrainerAngleLimit * projectedAngleSign) - projectedAngle) * acroTrainerGain;
 693                 resetIterm = true;
 694             }
 695         }
 696
 697         if (resetIterm) {
 698             pidData[axis].I = 0;
 699         }
 700
 701         if (axis == acroTrainerDebugAxis) {
 702             DEBUG_SET(DEBUG_ACRO_TRAINER, 0, lrintf(currentAngle * 10.0f));
 703             DEBUG_SET(DEBUG_ACRO_TRAINER, 1, acroTrainerAxisState[axis]);
 704             DEBUG_SET(DEBUG_ACRO_TRAINER, 2, lrintf(ret));
 705             DEBUG_SET(DEBUG_ACRO_TRAINER, 3, lrintf(projectedAngle * 10.0f));
 706         }
 707     }
 708
 709     return ret;
 710 }
 711 #endif // USE_ACRO_TRAINER
 712
 713 // Betaflight pid controller, which will be maintained in the future with additional features specialised for current (mini) multirotor usage.
 714 // Based on 2DOF reference design (matlab)
 715 void FAST_CODE pidController(const pidProfile_t *pidProfile, const rollAndPitchTrims_t *angleTrim, timeUs_t currentTimeUs)
 716 {
 717     static float previousGyroRateDterm[2];
 718     static float previousPidSetpoint[2];
 719
 720     const float tpaFactor = getThrottlePIDAttenuation();
 721     const float motorMixRange = getMotorMixRange();
 722
 723 #ifdef USE_YAW_SPIN_RECOVERY
 724     const bool yawSpinActive = gyroYawSpinDetected();
 725 #endif
 726
 727     // Dynamic i component,
 728     // gradually scale back integration when above windup point
 729     const float dynCi = MIN((1.0f - motorMixRange) * ITermWindupPointInv, 1.0f) * dT * itermAccelerator;
 730
 731     // Dynamic d component, enable 2-DOF PID controller only for rate mode
 732     const float dynCd = flightModeFlags ? 0.0f : dtermSetpointWeight;
 733
 734     // Precalculate gyro deta for D-term here, this allows loop unrolling
 735     float gyroRateDterm[2];
 736     for (int axis = FD_ROLL; axis < FD_YAW; ++axis) {
 737         gyroRateDterm[axis] = dtermNotchApplyFn((filter_t *) &dtermNotch[axis], gyro.gyroADCf[axis]);
 738         gyroRateDterm[axis] = dtermLowpassApplyFn((filter_t *) &dtermLowpass[axis], gyroRateDterm[axis]);
 739         gyroRateDterm[axis] = dtermLowpass2ApplyFn((filter_t *) &dtermLowpass2[axis], gyroRateDterm[axis]);
 740     }
 741
 742     rotateITermAndAxisError();
 743
 744     // ----------PID controller----------
 745     for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 746         float currentPidSetpoint = getSetpointRate(axis);
 747         if (maxVelocity[axis]) {
 748             currentPidSetpoint = accelerationLimit(axis, currentPidSetpoint);
 749         }
 750         // Yaw control is GYRO based, direct sticks control is applied to rate PID
 751         if ((FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE) || FLIGHT_MODE(GPS_RESCUE_MODE)) && axis != YAW) {
 752             currentPidSetpoint = pidLevel(axis, pidProfile, angleTrim, currentPidSetpoint);
 753         }
 754
 755 #ifdef USE_ACRO_TRAINER
 756         if ((axis != FD_YAW) && acroTrainerActive && !inCrashRecoveryMode) {
 757             currentPidSetpoint = applyAcroTrainer(axis, angleTrim, currentPidSetpoint);
 758         }
 759 #endif // USE_ACRO_TRAINER
 760
 761         // Handle yaw spin recovery - zero the setpoint on yaw to aid in recovery
 762         // It's not necessary to zero the set points for R/P because the PIDs will be zeroed below
 763 #ifdef USE_YAW_SPIN_RECOVERY
 764         if ((axis == FD_YAW) && yawSpinActive) {
 765             currentPidSetpoint = 0.0f;
 766         }
 767 #endif // USE_YAW_SPIN_RECOVERY
 768
 769 #if defined(USE_ABSOLUTE_CONTROL)
 770         // mix in a correction for accrued attitude error
 771         float acCorrection = 0;
 772         if (acGain > 0) {
 773             acCorrection = constrainf(axisError[axis] * acGain, -acLimit, acLimit);
 774             currentPidSetpoint += acCorrection;
 775         }
 776 #endif
 777
 778         // -----calculate error rate
 779         const float gyroRate = gyro.gyroADCf[axis]; // Process variable from gyro output in deg/sec
 780         float errorRate = currentPidSetpoint - gyroRate; // r - y
 781
 782         handleCrashRecovery(
 783             pidProfile->crash_recovery, angleTrim, axis, currentTimeUs, gyroRate,
 784             &currentPidSetpoint, &errorRate);
 785
 786         // --------low-level gyro-based PID based on 2DOF PID controller. ----------
 787         // 2-DOF PID controller with optional filter on derivative term.
 788         // b = 1 and only c (dtermSetpointWeight) can be tuned (amount derivative on measurement or error).
 789
 790         // -----calculate P component and add Dynamic Part based on stick input
 791         pidData[axis].P = pidCoefficient[axis].Kp * errorRate * tpaFactor;
 792         if (axis == FD_YAW) {
 793             pidData[axis].P = ptermYawLowpassApplyFn((filter_t *) &ptermYawLowpass, pidData[axis].P);
 794         }
 795
 796         // -----calculate I component
 797         float itermErrorRate = 0.0f;
 798 #if defined(USE_ABSOLUTE_CONTROL)
 799         float acErrorRate;
 800 #endif
 801 #if defined(USE_ITERM_RELAX)
 802         if (itermRelax && (axis < FD_YAW || itermRelax == ITERM_RELAX_RPY )) {
 803             float gyroTargetLow = pt1FilterApply(&windupLpf[axis][0], currentPidSetpoint);
 804             float gyroTargetHigh = pt1FilterApply(&windupLpf[axis][1], currentPidSetpoint);
 805 #if defined(USE_ABSOLUTE_CONTROL)
 806             gyroTargetLow += acCorrection;
 807             gyroTargetHigh += acCorrection;
 808 #endif
 809             if (axis < FD_YAW) {
 810                 int itemOffset = (axis << 1);
 811                 DEBUG_SET(DEBUG_ITERM_RELAX, itemOffset++, gyroTargetHigh);
 812                 DEBUG_SET(DEBUG_ITERM_RELAX, itemOffset, gyroTargetLow);
 813             }
 814             const float gmax = MAX(gyroTargetHigh, gyroTargetLow);
 815             const float gmin = MIN(gyroTargetHigh, gyroTargetLow);
 816             if (gyroRate < gmin || gyroRate > gmax) {
 817                 itermErrorRate = (gyroRate > gmax ? gmax : gmin ) - gyroRate;
 818             }
 819 #if defined(USE_ABSOLUTE_CONTROL)
 820             else {
 821                 itermErrorRate = acCorrection;
 822             }
 823             acErrorRate = itermErrorRate - acCorrection;
 824 #endif
 825         } else
 826 #endif // USE_ITERM_RELAX
 827         {
 828             itermErrorRate = errorRate;
 829 #if defined(USE_ABSOLUTE_CONTROL)
 830             acErrorRate = errorRate;
 831 #endif
 832         }
 833
 834 #if defined(USE_ABSOLUTE_CONTROL)
 835         if (acGain > 0) {
 836             axisError[axis] = constrainf(axisError[axis] + acErrorRate * dT, -acErrorLimit, acErrorLimit);
 837         }
 838 #endif
 839
 840         const float ITerm = pidData[axis].I;
 841         const float ITermNew = constrainf(ITerm + pidCoefficient[axis].Ki * itermErrorRate * dynCi, -itermLimit, itermLimit);
 842         const bool outputSaturated = mixerIsOutputSaturated(axis, errorRate);
 843         if (outputSaturated == false || ABS(ITermNew) < ABS(ITerm)) {
 844             // Only increase ITerm if output is not saturated
 845             pidData[axis].I = ITermNew;
 846         }
 847
 848         // -----calculate D component
 849         if (axis != FD_YAW) {
 850             // no transition if relaxFactor == 0
 851             float transition = relaxFactor > 0 ? MIN(1.f, getRcDeflectionAbs(axis) * relaxFactor) : 1;
 852
 853             // Divide rate change by dT to get differential (ie dr/dt).
 854             // dT is fixed and calculated from the target PID loop time
 855             // This is done to avoid DTerm spikes that occur with dynamically
 856             // calculated deltaT whenever another task causes the PID
 857             // loop execution to be delayed.
 858             const float delta =
 859                 - (gyroRateDterm[axis] - previousGyroRateDterm[axis]) / dT;
 860
 861             detectAndSetCrashRecovery(pidProfile->crash_recovery, axis, currentTimeUs, delta, errorRate);
 862
 863             pidData[axis].D = pidCoefficient[axis].Kd * delta * tpaFactor;
 864
 865             const float pidFeedForward =
 866                 pidCoefficient[axis].Kd * dynCd * transition *
 867                 (currentPidSetpoint - previousPidSetpoint[axis]) * tpaFactor / dT;
 868 #if defined(USE_SMART_FEEDFORWARD)
 869             bool addFeedforward = true;
 870             if (smartFeedforward) {
 871                 if (pidData[axis].P * pidFeedForward > 0) {
 872                     if (ABS(pidFeedForward) > ABS(pidData[axis].P)) {
 873                         pidData[axis].P = 0;
 874                     }
 875                     else {
 876                         addFeedforward = false;
 877                     }
 878                 }
 879             }
 880             if (addFeedforward)
 881 #endif
 882             {
 883                 pidData[axis].D += pidFeedForward;
 884             }
 885             previousGyroRateDterm[axis] = gyroRateDterm[axis];
 886             previousPidSetpoint[axis] = currentPidSetpoint;
 887
 888 #ifdef USE_YAW_SPIN_RECOVERY
 889             if (yawSpinActive)  {
 890                 // zero PIDs on pitch and roll leaving yaw P to correct spin
 891                 pidData[axis].P = 0;
 892                 pidData[axis].I = 0;
 893                 pidData[axis].D = 0;
 894             }
 895 #endif // USE_YAW_SPIN_RECOVERY
 896         }
 897     }
 898
 899     // calculating the PID sum
 900     pidData[FD_ROLL].Sum = pidData[FD_ROLL].P + pidData[FD_ROLL].I + pidData[FD_ROLL].D;
 901     pidData[FD_PITCH].Sum = pidData[FD_PITCH].P + pidData[FD_PITCH].I + pidData[FD_PITCH].D;
 902
 903 #ifdef USE_YAW_SPIN_RECOVERY
 904     if (yawSpinActive) {
 905     // yaw P alone to correct spin
 906         pidData[FD_YAW].I = 0;
 907     }
 908 #endif // USE_YAW_SPIN_RECOVERY
 909
 910     // YAW has no D
 911     pidData[FD_YAW].Sum = pidData[FD_YAW].P + pidData[FD_YAW].I;
 912
 913     // Disable PID control if at zero throttle or if gyro overflow detected
 914     // This may look very innefficient, but it is done on purpose to always show real CPU usage as in flight
 915     if (!pidStabilisationEnabled || gyroOverflowDetected()) {
 916         for (int axis = FD_ROLL; axis <= FD_YAW; ++axis) {
 917             pidData[axis].P = 0;
 918             pidData[axis].I = 0;
 919             pidData[axis].D = 0;
 920
 921             pidData[axis].Sum = 0;
 922         }
 923     }
 924 }
 925
 926 bool crashRecoveryModeActive(void)
 927 {
 928     return inCrashRecoveryMode;
 929 }
 930
 931 #ifdef USE_ACRO_TRAINER
 932 void pidSetAcroTrainerState(bool newState)
 933 {
 934     if (acroTrainerActive != newState) {
 935         if (newState) {
 936             pidAcroTrainerInit();
 937         }
 938         acroTrainerActive = newState;
 939     }
 940 }
 941 #endif // USE_ACRO_TRAINER