src/main/sensors/rangefinder.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 #ifdef USE_RANGEFINDER
  29
  30 #include "build/build_config.h"
  31 #include "build/debug.h"
  32
  33 #include "common/maths.h"
  34 #include "common/time.h"
  35 #include "common/utils.h"
  36
  37 #include "config/config.h"
  38 #include "config/feature.h"
  39
  40 #include "drivers/io.h"
  41 #include "drivers/rangefinder/rangefinder.h"
  42 #include "drivers/rangefinder/rangefinder_hcsr04.h"
  43 #include "drivers/rangefinder/rangefinder_lidartf.h"
  44 #include "drivers/time.h"
  45
  46 #include "fc/runtime_config.h"
  47
  48 #include "pg/pg.h"
  49 #include "pg/pg_ids.h"
  50
  51 #include "scheduler/scheduler.h"
  52
  53 #include "sensors/sensors.h"
  54 #include "sensors/rangefinder.h"
  55 #include "sensors/battery.h"
  56
  57 //#include "uav_interconnect/uav_interconnect.h"
  58
  59 // XXX Interface to CF/BF legacy(?) altitude estimation code.
  60 // XXX Will be gone once iNav's estimator is ported.
  61 int16_t rangefinderMaxRangeCm;
  62 int16_t rangefinderMaxAltWithTiltCm;
  63 int16_t rangefinderCfAltCm; // Complimentary Filter altitude
  64
  65 rangefinder_t rangefinder;
  66
  67 #define RANGEFINDER_HARDWARE_TIMEOUT_MS         500     // Accept 500ms of non-responsive sensor, report HW failure otherwise
  68
  69 #define RANGEFINDER_DYNAMIC_THRESHOLD           600     //Used to determine max. usable rangefinder disatance
  70 #define RANGEFINDER_DYNAMIC_FACTOR              75
  71
  72 PG_REGISTER_WITH_RESET_TEMPLATE(rangefinderConfig_t, rangefinderConfig, PG_RANGEFINDER_CONFIG, 0);
  73
  74 PG_RESET_TEMPLATE(rangefinderConfig_t, rangefinderConfig,
  75     .rangefinder_hardware = RANGEFINDER_NONE,
  76 );
  77
  78 #ifdef USE_RANGEFINDER_HCSR04
  79 PG_REGISTER_WITH_RESET_TEMPLATE(sonarConfig_t, sonarConfig, PG_SONAR_CONFIG, 1);
  80
  81 PG_RESET_TEMPLATE(sonarConfig_t, sonarConfig,
  82     .triggerTag = IO_TAG(RANGEFINDER_HCSR04_TRIGGER_PIN),
  83     .echoTag = IO_TAG(RANGEFINDER_HCSR04_ECHO_PIN),
  84 );
  85 #endif
  86
  87 /*
  88  * Detect which rangefinder is present
  89  */
  90 static bool rangefinderDetect(rangefinderDev_t * dev, uint8_t rangefinderHardwareToUse)
  91 {
  92     rangefinderType_e rangefinderHardware = RANGEFINDER_NONE;
  93     requestedSensors[SENSOR_INDEX_RANGEFINDER] = rangefinderHardwareToUse;
  94
  95     switch (rangefinderHardwareToUse) {
  96         case RANGEFINDER_HCSR04:
  97 #ifdef USE_RANGEFINDER_HCSR04
  98             {
  99                 if (hcsr04Detect(dev, sonarConfig())) {   // FIXME: Do actual detection if HC-SR04 is plugged in
 100                     rangefinderHardware = RANGEFINDER_HCSR04;
 101                     rescheduleTask(TASK_RANGEFINDER, TASK_PERIOD_MS(RANGEFINDER_HCSR04_TASK_PERIOD_MS));
 102                 }
 103             }
 104 #endif
 105             break;
 106
 107         case RANGEFINDER_TFMINI:
 108 #if defined(USE_RANGEFINDER_TF)
 109             if (lidarTFminiDetect(dev)) {
 110                 rangefinderHardware = RANGEFINDER_TFMINI;
 111                 rescheduleTask(TASK_RANGEFINDER, TASK_PERIOD_MS(RANGEFINDER_TF_TASK_PERIOD_MS));
 112             }
 113 #endif
 114             break;
 115
 116         case RANGEFINDER_TF02:
 117 #if defined(USE_RANGEFINDER_TF)
 118             if (lidarTF02Detect(dev)) {
 119                 rangefinderHardware = RANGEFINDER_TF02;
 120                 rescheduleTask(TASK_RANGEFINDER, TASK_PERIOD_MS(RANGEFINDER_TF_TASK_PERIOD_MS));
 121             }
 122 #endif
 123             break;
 124
 125         case RANGEFINDER_NONE:
 126             rangefinderHardware = RANGEFINDER_NONE;
 127             break;
 128     }
 129
 130     if (rangefinderHardware == RANGEFINDER_NONE) {
 131         sensorsClear(SENSOR_RANGEFINDER);
 132         return false;
 133     }
 134
 135     detectedSensors[SENSOR_INDEX_RANGEFINDER] = rangefinderHardware;
 136     sensorsSet(SENSOR_RANGEFINDER);
 137     return true;
 138 }
 139
 140 void rangefinderResetDynamicThreshold(void)
 141 {
 142     rangefinder.snrThresholdReached = false;
 143     rangefinder.dynamicDistanceThreshold = 0;
 144 }
 145
 146 bool rangefinderInit(void)
 147 {
 148     if (!rangefinderDetect(&rangefinder.dev, rangefinderConfig()->rangefinder_hardware)) {
 149         return false;
 150     }
 151
 152     rangefinder.dev.init(&rangefinder.dev);
 153     rangefinder.rawAltitude = RANGEFINDER_OUT_OF_RANGE;
 154     rangefinder.calculatedAltitude = RANGEFINDER_OUT_OF_RANGE;
 155     rangefinder.maxTiltCos = cos_approx(DECIDEGREES_TO_RADIANS(rangefinder.dev.detectionConeExtendedDeciDegrees / 2.0f));
 156     rangefinder.lastValidResponseTimeMs = millis();
 157     rangefinder.snr = 0;
 158
 159     rangefinderResetDynamicThreshold();
 160
 161     // XXX Interface to CF/BF legacy(?) altitude estimation code.
 162     // XXX Will be gone once iNav's estimator is ported.
 163     rangefinderMaxRangeCm = rangefinder.dev.maxRangeCm;
 164     rangefinderMaxAltWithTiltCm = rangefinderMaxRangeCm * rangefinder.maxTiltCos;
 165     rangefinderCfAltCm = rangefinder.dev.maxRangeCm / 2 ; // Complimentary Filter altitude
 166
 167     return true;
 168 }
 169
 170 static int32_t applyMedianFilter(int32_t newReading)
 171 {
 172     #define DISTANCE_SAMPLES_MEDIAN 5
 173     static int32_t filterSamples[DISTANCE_SAMPLES_MEDIAN];
 174     static int filterSampleIndex = 0;
 175     static bool medianFilterReady = false;
 176
 177     if (newReading > RANGEFINDER_OUT_OF_RANGE) {// only accept samples that are in range
 178         filterSamples[filterSampleIndex] = newReading;
 179         ++filterSampleIndex;
 180         if (filterSampleIndex == DISTANCE_SAMPLES_MEDIAN) {
 181             filterSampleIndex = 0;
 182             medianFilterReady = true;
 183         }
 184     }
 185     return medianFilterReady ? quickMedianFilter5(filterSamples) : newReading;
 186 }
 187
 188 static int16_t computePseudoSnr(int32_t newReading) {
 189     #define SNR_SAMPLES 5
 190     static int16_t snrSamples[SNR_SAMPLES];
 191     static uint8_t snrSampleIndex = 0;
 192     static int32_t previousReading = RANGEFINDER_OUT_OF_RANGE;
 193     static bool snrReady = false;
 194     int16_t pseudoSnr = 0;
 195
 196     const int delta = newReading - previousReading;
 197     snrSamples[snrSampleIndex] = constrain(delta * delta / 10, 0, 6400);
 198     ++snrSampleIndex;
 199     if (snrSampleIndex == SNR_SAMPLES) {
 200         snrSampleIndex = 0;
 201         snrReady = true;
 202     }
 203
 204     previousReading = newReading;
 205
 206     if (snrReady) {
 207
 208         for (uint8_t i = 0; i < SNR_SAMPLES; i++) {
 209             pseudoSnr += snrSamples[i];
 210         }
 211
 212         return constrain(pseudoSnr, 0, 32000);
 213     } else {
 214         return RANGEFINDER_OUT_OF_RANGE;
 215     }
 216 }
 217
 218 /*
 219  * This is called periodically by the scheduler
 220  */
 221 void rangefinderUpdate(void)
 222 {
 223     if (rangefinder.dev.update) {
 224         rangefinder.dev.update(&rangefinder.dev);
 225     }
 226 }
 227
 228 bool isSurfaceAltitudeValid() {
 229
 230     /*
 231      * Preconditions: raw and calculated altidude > 0
 232      * SNR lower than threshold
 233      */
 234     if (
 235         rangefinder.calculatedAltitude > 0 &&
 236         rangefinder.rawAltitude > 0 &&
 237         rangefinder.snr < RANGEFINDER_DYNAMIC_THRESHOLD
 238     ) {
 239
 240         /*
 241          * When critical altitude was determined, distance reported by rangefinder
 242          * has to be lower than it to assume healthy readout
 243          */
 244         if (rangefinder.snrThresholdReached) {
 245             return (rangefinder.rawAltitude < rangefinder.dynamicDistanceThreshold);
 246         } else {
 247             return true;
 248         }
 249
 250     } else {
 251         return false;
 252     }
 253
 254 }
 255
 256 /**
 257  * Get the last distance measured by the sonar in centimeters. When the ground is too far away, RANGEFINDER_OUT_OF_RANGE is returned.
 258  */
 259 bool rangefinderProcess(float cosTiltAngle)
 260 {
 261     if (rangefinder.dev.read) {
 262         const int32_t distance = rangefinder.dev.read(&rangefinder.dev);
 263
 264         // If driver reported no new measurement - don't do anything
 265         if (distance == RANGEFINDER_NO_NEW_DATA) {
 266             return false;
 267         }
 268
 269         if (distance >= 0) {
 270             rangefinder.lastValidResponseTimeMs = millis();
 271             rangefinder.rawAltitude = applyMedianFilter(distance);
 272         } else if (distance == RANGEFINDER_OUT_OF_RANGE) {
 273             rangefinder.lastValidResponseTimeMs = millis();
 274             rangefinder.rawAltitude = RANGEFINDER_OUT_OF_RANGE;
 275         }
 276         else {
 277             // Invalid response / hardware failure
 278             rangefinder.rawAltitude = RANGEFINDER_HARDWARE_FAILURE;
 279         }
 280
 281         rangefinder.snr = computePseudoSnr(distance);
 282
 283         if (rangefinder.snrThresholdReached == false && rangefinder.rawAltitude > 0) {
 284
 285             if (rangefinder.snr < RANGEFINDER_DYNAMIC_THRESHOLD && rangefinder.dynamicDistanceThreshold < rangefinder.rawAltitude) {
 286                 rangefinder.dynamicDistanceThreshold = rangefinder.rawAltitude * RANGEFINDER_DYNAMIC_FACTOR / 100;
 287             }
 288
 289             if (rangefinder.snr >= RANGEFINDER_DYNAMIC_THRESHOLD) {
 290                 rangefinder.snrThresholdReached = true;
 291             }
 292
 293         }
 294
 295         DEBUG_SET(DEBUG_RANGEFINDER, 3, rangefinder.snr);
 296
 297         DEBUG_SET(DEBUG_RANGEFINDER_QUALITY, 0, rangefinder.rawAltitude);
 298         DEBUG_SET(DEBUG_RANGEFINDER_QUALITY, 1, rangefinder.snrThresholdReached);
 299         DEBUG_SET(DEBUG_RANGEFINDER_QUALITY, 2, rangefinder.dynamicDistanceThreshold);
 300         DEBUG_SET(DEBUG_RANGEFINDER_QUALITY, 3, isSurfaceAltitudeValid());
 301
 302     }
 303     else {
 304         // Bad configuration
 305         rangefinder.rawAltitude = RANGEFINDER_OUT_OF_RANGE;
 306     }
 307
 308     /**
 309     * Apply tilt correction to the given raw sonar reading in order to compensate for the tilt of the craft when estimating
 310     * the altitude. Returns the computed altitude in centimeters.
 311     *
 312     * When the ground is too far away or the tilt is too large, RANGEFINDER_OUT_OF_RANGE is returned.
 313     */
 314     if (cosTiltAngle < rangefinder.maxTiltCos || rangefinder.rawAltitude < 0) {
 315         rangefinder.calculatedAltitude = RANGEFINDER_OUT_OF_RANGE;
 316     } else {
 317         rangefinder.calculatedAltitude = rangefinder.rawAltitude * cosTiltAngle;
 318     }
 319
 320     DEBUG_SET(DEBUG_RANGEFINDER, 1, rangefinder.rawAltitude);
 321     DEBUG_SET(DEBUG_RANGEFINDER, 2, rangefinder.calculatedAltitude);
 322
 323     return true;
 324 }
 325
 326 /**
 327  * Get the latest altitude that was computed, or RANGEFINDER_OUT_OF_RANGE if sonarCalculateAltitude
 328  * has never been called.
 329  */
 330 int32_t rangefinderGetLatestAltitude(void)
 331 {
 332     return rangefinder.calculatedAltitude;
 333 }
 334
 335 int32_t rangefinderGetLatestRawAltitude(void) {
 336     return rangefinder.rawAltitude;
 337 }
 338
 339 bool rangefinderIsHealthy(void)
 340 {
 341     return (millis() - rangefinder.lastValidResponseTimeMs) < RANGEFINDER_HARDWARE_TIMEOUT_MS;
 342 }
 343 #endif
 344