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Gps rescue pid controller based on vertical velocity (#8015) 

Gps rescue pid controller based on vertical velocity
This commit is contained in:
Michael Keller 2019-07-01 23:45:28 +12:00 committed by GitHub
parent 12a02dfa6e a3d43832f2
commit aba49b39ae
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 86 additions and 19 deletions
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1
src/main/build/debug.c
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@ -91,4 +91,5 @@ const char * const debugModeNames[DEBUG_COUNT] = {
"CRSF_LINK_STATISTICS_PWR",
"CRSF_LINK_STATISTICS_DOWN",
"BARO",
"GPS_RESCUE_THROTTLE_PID",
};

1
src/main/build/debug.h
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@ -107,6 +107,7 @@ typedef enum {
DEBUG_CRSF_LINK_STATISTICS_PWR,
DEBUG_CRSF_LINK_STATISTICS_DOWN,
DEBUG_BARO,
DEBUG_GPS_RESCUE_THROTTLE_PID,
DEBUG_COUNT
} debugType_e;

2
src/main/cli/settings.c
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@ -909,6 +909,8 @@ const clivalue_t valueTable[] = {
{ "gps_rescue_throttle_min", VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 1000, 2000 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, throttleMin) },
{ "gps_rescue_throttle_max", VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 1000, 2000 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, throttleMax) },
{ "gps_rescue_ascend_rate", VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 100, 2500 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, ascendRate) },
{ "gps_rescue_descend_rate", VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 100, 500 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, descendRate) },
{ "gps_rescue_throttle_hover", VAR_UINT16 | MASTER_VALUE, .config.minmaxUnsigned = { 1000, 2000 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, throttleHover) },
{ "gps_rescue_sanity_checks", VAR_UINT8 | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_GPS_RESCUE_SANITY_CHECK }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, sanityChecks) },
{ "gps_rescue_min_sats", VAR_UINT8 | MASTER_VALUE, .config.minmaxUnsigned = { 5, 50 }, PG_GPS_RESCUE, offsetof(gpsRescueConfig_t, minSats) },

93
src/main/flight/gps_rescue.c
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@ -122,10 +122,27 @@ typedef enum {
CURRENT_ALT
} altitudeMode_e;
typedef struct {
float Kp;
float Ki;
float Kd;
} throttle_s;
#define GPS_RESCUE_MAX_YAW_RATE 180 // deg/sec max yaw rate
#define GPS_RESCUE_RATE_SCALE_DEGREES 45 // Scale the commanded yaw rate when the error is less then this angle
#define GPS_RESCUE_SLOWDOWN_DISTANCE_M 200 // distance from home to start decreasing speed
#define GPS_RESCUE_MIN_DESCENT_DIST_M 30 // minimum descent distance allowed
#define GPS_RESCUE_ZVELOCITY_THRESHOLD 300 // altitude threshold for start decreasing z velocity
#define GPS_RESCUE_LANDING_ZVELOCITY 80 // descend velocity for final landing phase
#define GPS_RESCUE_ITERM_WINDUP 100 // reset I term after z velocity error of 100 cm/s
#define GPS_RESCUE_MAX_ITERM_ACC 250.0f //max allowed iterm value
#define GPS_RESCUE_SLOWDOWN_ALT 500 // the altitude after which the quad begins to slow down the descend velocity
#define GPS_RESCUE_MINIMUM_ZVELOCITY 50 // minimum speed for final landing phase
#define GPS_RESCUE_ALMOST_LANDING_ALT 100 // altitude after which the quad increases ground detection sensitivity
#define GPS_RESCUE_THROTTLE_P_SCALE 0.0003125f // pid scaler for P term
#define GPS_RESCUE_THROTTLE_I_SCALE 0.1f // pid scaler for I term
#define GPS_RESCUE_THROTTLE_D_SCALE 0.0003125f // pid scaler for D term
#ifdef USE_MAG
#define GPS_RESCUE_USE_MAG true
@ -147,7 +164,7 @@ PG_RESET_TEMPLATE(gpsRescueConfig_t, gpsRescueConfig,
.velI = 20,
.velD = 15,
.yawP = 40,
.throttleMin = 1200,
.throttleMin = 1100,
.throttleMax = 1600,
.throttleHover = 1280,
.sanityChecks = RESCUE_SANITY_ON,
@ -158,6 +175,8 @@ PG_RESET_TEMPLATE(gpsRescueConfig_t, gpsRescueConfig,
.targetLandingAltitudeM = 5,
.targetLandingDistanceM = 10,
.altitudeMode = MAX_ALT,
.ascendRate = 500,
.descendRate = 150,
);
static uint16_t rescueThrottle;
@ -174,6 +193,7 @@ static bool newGPSData = false;
rescueState_s rescueState;
altitudeMode_e altitudeMode;
throttle_s throttle;
/*
If we have new GPS data, update home heading
@ -264,15 +284,19 @@ static void rescueAttainPosition()
// Speed and altitude controller internal variables
static float previousSpeedError = 0;
static int16_t speedIntegral = 0;
static float previousAltitudeError = 0;
static int16_t altitudeIntegral = 0;
int zVelocityError;
static int previousZVelocityError = 0;
static float zVelocityIntegral = 0;
static float scalingRate = 0;
static int16_t altitudeAdjustment = 0;
if (rescueState.phase == RESCUE_INITIALIZE) {
// Initialize internal variables each time GPS Rescue is started
previousSpeedError = 0;
speedIntegral = 0;
previousAltitudeError = 0;
altitudeIntegral = 0;
previousZVelocityError = 0;
zVelocityIntegral = 0;
altitudeAdjustment = 0;
}
// Point to home if that is in our intent
@ -305,26 +329,53 @@ static void rescueAttainPosition()
/**
Altitude controller
*/
const int16_t altitudeError = (rescueState.intent.targetAltitudeCm - rescueState.sensor.currentAltitudeCm) / 100; // Error in meters
const int16_t altitudeDerivative = altitudeError - previousAltitudeError;
const int16_t altitudeError = rescueState.intent.targetAltitudeCm - rescueState.sensor.currentAltitudeCm;
// Only allow integral windup within +-15m absolute altitude error
if (ABS(altitudeError) < 25) {
altitudeIntegral = constrain(altitudeIntegral + altitudeError, -250, 250);
// P component
if (ABS(altitudeError) > 0 && ABS(altitudeError) < GPS_RESCUE_ZVELOCITY_THRESHOLD){
scalingRate = (float)altitudeError / GPS_RESCUE_ZVELOCITY_THRESHOLD;
} else {
altitudeIntegral = 0;
scalingRate = 1;
}
previousAltitudeError = altitudeError;
if (altitudeError > 0) {
zVelocityError = gpsRescueConfig()->ascendRate * scalingRate - rescueState.sensor.zVelocity;
} else if (altitudeError < 0) {
if (rescueState.sensor.currentAltitudeCm <= GPS_RESCUE_SLOWDOWN_ALT) {
const int16_t rescueLandingDescendVel = MAX(GPS_RESCUE_LANDING_ZVELOCITY * rescueState.sensor.currentAltitudeCm / GPS_RESCUE_SLOWDOWN_ALT, GPS_RESCUE_MINIMUM_ZVELOCITY);
zVelocityError = -rescueLandingDescendVel - rescueState.sensor.zVelocity;
} else {
zVelocityError = -gpsRescueConfig()->descendRate * scalingRate - rescueState.sensor.zVelocity;
}
} else {
zVelocityError = 0;
}
// I component
if (ABS(zVelocityError) < GPS_RESCUE_ITERM_WINDUP) {
zVelocityIntegral = constrainf(zVelocityIntegral + zVelocityError / 100.0f, -GPS_RESCUE_MAX_ITERM_ACC, GPS_RESCUE_MAX_ITERM_ACC);
} else {
zVelocityIntegral = 0;
}
// D component
const int zVelocityDerivative = zVelocityError - previousZVelocityError;
previousZVelocityError = zVelocityError;
const int16_t altitudeAdjustment = (gpsRescueConfig()->throttleP * altitudeError + (gpsRescueConfig()->throttleI * altitudeIntegral) / 10 + gpsRescueConfig()->throttleD * altitudeDerivative) / ct / 20;
const int16_t hoverAdjustment = (hoverThrottle - 1000) / ct;
altitudeAdjustment = constrain(altitudeAdjustment + (throttle.Kp * zVelocityError + throttle.Ki * zVelocityIntegral + throttle.Kd * zVelocityDerivative),
gpsRescueConfig()->throttleMin - 1000 - hoverAdjustment, gpsRescueConfig()->throttleMax - 1000 - hoverAdjustment);
rescueThrottle = constrain(1000 + altitudeAdjustment + hoverAdjustment, gpsRescueConfig()->throttleMin, gpsRescueConfig()->throttleMax);
DEBUG_SET(DEBUG_RTH, 0, rescueThrottle);
DEBUG_SET(DEBUG_RTH, 1, gpsRescueAngle[AI_PITCH]);
DEBUG_SET(DEBUG_RTH, 2, altitudeAdjustment);
DEBUG_SET(DEBUG_GPS_RESCUE_THROTTLE_PID, 0, throttle.Kp * zVelocityError);
DEBUG_SET(DEBUG_GPS_RESCUE_THROTTLE_PID, 1, throttle.Ki * zVelocityIntegral);
DEBUG_SET(DEBUG_GPS_RESCUE_THROTTLE_PID, 2, throttle.Kd * zVelocityDerivative);
DEBUG_SET(DEBUG_GPS_RESCUE_THROTTLE_PID, 3, rescueState.sensor.zVelocity);
}
static void performSanityChecks()
@ -495,7 +546,8 @@ void updateGPSRescueState(void)
static float_t lineSlope;
static float_t lineOffsetM;
static int32_t newSpeed;
static uint32_t newAltitude;
static int32_t newAltitude;
float magnitudeTrigger;
if (!FLIGHT_MODE(GPS_RESCUE_MODE)) {
rescueStop();
@ -520,6 +572,10 @@ void updateGPSRescueState(void)
hoverThrottle = gpsRescueConfig()->throttleHover;
}
throttle.Kp = gpsRescueConfig()->throttleP * GPS_RESCUE_THROTTLE_P_SCALE;
throttle.Ki = gpsRescueConfig()->throttleI * GPS_RESCUE_THROTTLE_I_SCALE;
throttle.Kd = gpsRescueConfig()->throttleD * GPS_RESCUE_THROTTLE_D_SCALE;
if (!STATE(GPS_FIX_HOME)) {
setArmingDisabled(ARMING_DISABLED_ARM_SWITCH);
disarm();
@ -612,9 +668,14 @@ void updateGPSRescueState(void)
case RESCUE_LANDING:
// We have reached the XYZ envelope to be considered at "home". We need to land gently and check our accelerometer for abnormal data.
// At this point, do not let the target altitude go up anymore, so if we overshoot, we dont' move in a parabolic trajectory
// If we are over 150% of average magnitude, just disarm since we're pretty much home
if (rescueState.sensor.accMagnitude > rescueState.sensor.accMagnitudeAvg * 1.5) {
if (rescueState.sensor.currentAltitudeCm < GPS_RESCUE_ALMOST_LANDING_ALT) {
magnitudeTrigger = rescueState.sensor.accMagnitudeAvg * 1.2;
} else {
magnitudeTrigger = rescueState.sensor.accMagnitudeAvg * 1.5;
}
if (rescueState.sensor.accMagnitude > magnitudeTrigger) {
setArmingDisabled(ARMING_DISABLED_ARM_SWITCH);
disarm();
rescueState.phase = RESCUE_COMPLETE;

2
src/main/flight/gps_rescue.h
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@ -40,6 +40,8 @@ typedef struct gpsRescue_s {
uint16_t targetLandingAltitudeM; //meters
uint16_t targetLandingDistanceM; //meters
uint8_t altitudeMode;
uint16_t ascendRate;
uint16_t descendRate;
} gpsRescueConfig_t;
PG_DECLARE(gpsRescueConfig_t, gpsRescueConfig);