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LibrePilot/flight/modules/PathFollower/pathfollower.c
abeck70 2b6d79467c gpsassist:code review comments 
1. Defines
2. Name of adjustments changed to vtolSelfTuningStats
2015-01-09 07:51:37 +11:00

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/**
******************************************************************************
*
* @file pathfollower.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief This module compared @ref PositionActuatl to @ref ActiveWaypoint
* and sets @ref AttitudeDesired. It only does this when the FlightMode field
* of @ref ManualControlCommand is Auto.
*
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* Input object: PathDesired
* Input object: PositionState
* Input object: ManualControlCommand
* Output object: StabilizationDesired
*
* This module acts as "autopilot" - it controls the setpoints of stabilization
* based on current flight situation and desired flight path (PathDesired) as
* directed by flightmode selection or pathplanner
* This is a periodic delayed callback module
*
* Modules have no API, all communication to other modules is done through UAVObjects.
* However modules may use the API exposed by shared libraries.
* See the OpenPilot wiki for more details.
* http://www.openpilot.org/OpenPilot_Application_Architecture
*
*/
#include <openpilot.h>
#include <callbackinfo.h>
#include <math.h>
#include <pid.h>
#include <CoordinateConversions.h>
#include <sin_lookup.h>
#include <pathdesired.h>
#include <paths.h>
#include "plans.h"
#include <sanitycheck.h>
#include <fixedwingpathfollowersettings.h>
#include <fixedwingpathfollowerstatus.h>
#include <vtolpathfollowersettings.h>
#include <flightstatus.h>
#include <flightmodesettings.h>
#include <pathstatus.h>
#include <positionstate.h>
#include <velocitystate.h>
#include <velocitydesired.h>
#include <stabilizationdesired.h>
#include <airspeedstate.h>
#include <attitudestate.h>
#include <takeofflocation.h>
#include <poilocation.h>
#include <manualcontrolcommand.h>
#include <systemsettings.h>
#include <stabilizationbank.h>
#include <vtolselftuningstats.h>
#include <pathsummary.h>
// Private constants
#define CALLBACK_PRIORITY CALLBACK_PRIORITY_LOW
#define CBTASK_PRIORITY CALLBACK_TASK_FLIGHTCONTROL
#define PF_IDLE_UPDATE_RATE_MS 100
#define STACK_SIZE_BYTES 2048
#define DEADBAND_HIGH 0.10f
#define DEADBAND_LOW -0.10f
#define BRAKE_FRACTIONALPROGRESS_STARTVELOCITYCHECK 0.95f
#define BRAKE_EXIT_VELOCITY_LIMIT 0.2f
#define BRAKE_RATE_MINIMUM 0.2f
#define NEUTRALTHRUST_PH_POSITIONAL_ERROR_LIMIT 0.5f
#define NEUTRALTHRUST_PH_VEL_DESIRED_LIMIT 0.2f
#define NEUTRALTHRUST_PH_VEL_STATE_LIMIT 0.2f
#define NEUTRALTHRUST_PH_VEL_ERROR_LIMIT 0.1f
#define NEUTRALTHRUST_START_DELAY (2 * 20) // 2 seconds at rate of 20Hz (50ms update rate)
#define NEUTRALTHRUST_END_COUNT (NEUTRALTHRUST_START_DELAY + (4 * 20)) // 4 second sample
// Private types
struct Globals {
struct pid PIDposH[2];
struct pid PIDposV;
struct pid PIDvel[3]; // North, East, Down
struct pid BrakePIDvel[2]; // North, East
struct pid PIDcourse;
struct pid PIDspeed;
struct pid PIDpower;
float poiRadius;
float vtolEmergencyFallback;
bool vtolEmergencyFallbackSwitch;
};
struct NeutralThrustEstimation {
uint32_t count;
float sum;
float average;
float correction;
float algo_erro_check;
float min;
float max;
bool start_sampling;
bool have_correction;
};
static struct NeutralThrustEstimation neutralThrustEst;
// Private variables
static DelayedCallbackInfo *pathFollowerCBInfo;
static uint32_t updatePeriod = PF_IDLE_UPDATE_RATE_MS;
static struct Globals global;
static PathStatusData pathStatus;
static PathDesiredData pathDesired;
static FixedWingPathFollowerSettingsData fixedWingPathFollowerSettings;
static VtolPathFollowerSettingsData vtolPathFollowerSettings;
static FlightStatusData flightStatus;
static PathSummaryData pathSummary;
// correct speed by measured airspeed
static float indicatedAirspeedStateBias = 0.0f;
// Private functions
static void pathFollowerTask(void);
static void resetGlobals();
static void SettingsUpdatedCb(UAVObjEvent *ev);
static uint8_t updateAutoPilotByFrameType();
static uint8_t updateAutoPilotFixedWing();
static uint8_t updateAutoPilotVtol();
static float updateTailInBearing();
static float updateCourseBearing();
static float updatePathBearing();
static float updatePOIBearing();
static void processPOI();
static void updateBrakeVelocity(float startingVelocity, float dT, float brakeRate, float currentVelocity, float *updatedVelocity);
static void updatePathVelocity(float kFF, bool limited);
static uint8_t updateFixedDesiredAttitude();
static int8_t updateVtolDesiredAttitude(bool yaw_attitude, float yaw_direction);
static void updateFixedAttitude();
static void updateVtolDesiredAttitudeEmergencyFallback();
static void airspeedStateUpdatedCb(UAVObjEvent *ev);
static bool correctCourse(float *C, float *V, float *F, float s);
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t PathFollowerStart()
{
// Start main task
PathStatusGet(&pathStatus);
SettingsUpdatedCb(NULL);
PIOS_CALLBACKSCHEDULER_Dispatch(pathFollowerCBInfo);
return 0;
}
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t PathFollowerInitialize()
{
// initialize objects
FixedWingPathFollowerSettingsInitialize();
FixedWingPathFollowerStatusInitialize();
VtolPathFollowerSettingsInitialize();
FlightStatusInitialize();
FlightModeSettingsInitialize();
PathStatusInitialize();
PathSummaryInitialize();
PathDesiredInitialize();
PositionStateInitialize();
VelocityStateInitialize();
VelocityDesiredInitialize();
StabilizationDesiredInitialize();
AirspeedStateInitialize();
AttitudeStateInitialize();
TakeOffLocationInitialize();
PoiLocationInitialize();
ManualControlCommandInitialize();
SystemSettingsInitialize();
StabilizationBankInitialize();
VtolSelfTuningStatsInitialize();
// reset integrals
resetGlobals();
// Create object queue
pathFollowerCBInfo = PIOS_CALLBACKSCHEDULER_Create(&pathFollowerTask, CALLBACK_PRIORITY, CBTASK_PRIORITY, CALLBACKINFO_RUNNING_PATHFOLLOWER, STACK_SIZE_BYTES);
FixedWingPathFollowerSettingsConnectCallback(&SettingsUpdatedCb);
VtolPathFollowerSettingsConnectCallback(&SettingsUpdatedCb);
PathDesiredConnectCallback(SettingsUpdatedCb);
AirspeedStateConnectCallback(airspeedStateUpdatedCb);
return 0;
}
MODULE_INITCALL(PathFollowerInitialize, PathFollowerStart);
/**
* Module thread, should not return.
*/
static void pathFollowerTask(void)
{
FlightStatusGet(&flightStatus);
if (flightStatus.ControlChain.PathFollower != FLIGHTSTATUS_CONTROLCHAIN_TRUE) {
resetGlobals();
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_UNINITIALISED);
PIOS_CALLBACKSCHEDULER_Schedule(pathFollowerCBInfo, PF_IDLE_UPDATE_RATE_MS, CALLBACK_UPDATEMODE_SOONER);
return;
}
if (flightStatus.FlightMode == FLIGHTSTATUS_FLIGHTMODE_POI) { // TODO Hack from vtolpathfollower, move into manualcontrol!
processPOI();
}
int16_t old_uid = pathStatus.UID;
pathStatus.UID = pathDesired.UID;
pathStatus.Status = PATHSTATUS_STATUS_INPROGRESS;
if (pathDesired.ModeParameters[PATHDESIRED_MODEPARAMETER_BRAKE_TIMEOUT] > 0.0f) {
if (old_uid != pathStatus.UID) {
pathStatus.path_time = 0.0f;
} else {
pathStatus.path_time += updatePeriod / 1000.0f;
}
}
switch (pathDesired.Mode) {
case PATHDESIRED_MODE_FLYENDPOINT:
case PATHDESIRED_MODE_FLYVECTOR:
case PATHDESIRED_MODE_BRAKE:
case PATHDESIRED_MODE_FLYCIRCLERIGHT:
case PATHDESIRED_MODE_FLYCIRCLELEFT:
{
uint8_t result = updateAutoPilotByFrameType();
if (result) {
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_OK);
} else {
pathStatus.Status = PATHSTATUS_STATUS_CRITICAL;
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_WARNING);
}
}
break;
case PATHDESIRED_MODE_FIXEDATTITUDE:
updateFixedAttitude(pathDesired.ModeParameters);
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_OK);
break;
case PATHDESIRED_MODE_DISARMALARM:
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_CRITICAL);
break;
default:
pathStatus.Status = PATHSTATUS_STATUS_CRITICAL;
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_ERROR);
break;
}
PathStatusSet(&pathStatus);
PIOS_CALLBACKSCHEDULER_Schedule(pathFollowerCBInfo, updatePeriod, CALLBACK_UPDATEMODE_SOONER);
}
static void SettingsUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
FixedWingPathFollowerSettingsGet(&fixedWingPathFollowerSettings);
pid_configure(&global.PIDcourse, fixedWingPathFollowerSettings.CoursePI.Kp, fixedWingPathFollowerSettings.CoursePI.Ki, 0.0f, fixedWingPathFollowerSettings.CoursePI.ILimit);
pid_configure(&global.PIDspeed, fixedWingPathFollowerSettings.SpeedPI.Kp, fixedWingPathFollowerSettings.SpeedPI.Ki, 0.0f, fixedWingPathFollowerSettings.SpeedPI.ILimit);
pid_configure(&global.PIDpower, fixedWingPathFollowerSettings.PowerPI.Kp, fixedWingPathFollowerSettings.PowerPI.Ki, 0.0f, fixedWingPathFollowerSettings.PowerPI.ILimit);
VtolPathFollowerSettingsGet(&vtolPathFollowerSettings);
pid_configure(&global.PIDvel[0], vtolPathFollowerSettings.HorizontalVelPID.Kp, vtolPathFollowerSettings.HorizontalVelPID.Ki, vtolPathFollowerSettings.HorizontalVelPID.Kd, vtolPathFollowerSettings.HorizontalVelPID.ILimit);
pid_configure(&global.PIDvel[1], vtolPathFollowerSettings.HorizontalVelPID.Kp, vtolPathFollowerSettings.HorizontalVelPID.Ki, vtolPathFollowerSettings.HorizontalVelPID.Kd, vtolPathFollowerSettings.HorizontalVelPID.ILimit);
pid_configure(&global.PIDvel[2], vtolPathFollowerSettings.VerticalVelPID.Kp, vtolPathFollowerSettings.VerticalVelPID.Ki, vtolPathFollowerSettings.VerticalVelPID.Kd, vtolPathFollowerSettings.VerticalVelPID.ILimit);
pid_configure(&global.BrakePIDvel[0], vtolPathFollowerSettings.BrakeHorizontalVelPID.Kp, vtolPathFollowerSettings.BrakeHorizontalVelPID.Ki, vtolPathFollowerSettings.BrakeHorizontalVelPID.Kd, vtolPathFollowerSettings.BrakeHorizontalVelPID.ILimit);
pid_configure(&global.BrakePIDvel[1], vtolPathFollowerSettings.BrakeHorizontalVelPID.Kp, vtolPathFollowerSettings.BrakeHorizontalVelPID.Ki, vtolPathFollowerSettings.BrakeHorizontalVelPID.Kd, vtolPathFollowerSettings.BrakeHorizontalVelPID.ILimit);
PathDesiredGet(&pathDesired);
}
static void airspeedStateUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
AirspeedStateData airspeedState;
VelocityStateData velocityState;
AirspeedStateGet(&airspeedState);
VelocityStateGet(&velocityState);
float airspeedVector[2];
float yaw;
AttitudeStateYawGet(&yaw);
airspeedVector[0] = cos_lookup_deg(yaw);
airspeedVector[1] = sin_lookup_deg(yaw);
// vector projection of groundspeed on airspeed vector to handle both forward and backwards movement
float groundspeedProjection = velocityState.North * airspeedVector[0] + velocityState.East * airspeedVector[1];
indicatedAirspeedStateBias = airspeedState.CalibratedAirspeed - groundspeedProjection;
// note - we do fly by Indicated Airspeed (== calibrated airspeed) however
// since airspeed is updated less often than groundspeed, we use sudden
// changes to groundspeed to offset the airspeed by the same measurement.
// This has a side effect that in the absence of any airspeed updates, the
// pathfollower will fly using groundspeed.
}
/**
* reset integrals
*/
static void resetGlobals()
{
pid_zero(&global.PIDposH[0]);
pid_zero(&global.PIDposH[1]);
pid_zero(&global.PIDposV);
pid_zero(&global.PIDvel[0]);
pid_zero(&global.PIDvel[1]);
pid_zero(&global.PIDvel[2]);
pid_zero(&global.BrakePIDvel[0]);
pid_zero(&global.BrakePIDvel[1]);
pid_zero(&global.PIDcourse);
pid_zero(&global.PIDspeed);
pid_zero(&global.PIDpower);
global.poiRadius = 0.0f;
global.vtolEmergencyFallback = 0;
global.vtolEmergencyFallbackSwitch = false;
// reset neutral thrust assessment. We restart this process
// and do once for each position hold engagement
neutralThrustEst.start_sampling = false;
neutralThrustEst.count = 0;
neutralThrustEst.sum = 0.0f;
neutralThrustEst.have_correction = false;
neutralThrustEst.average = 0.0f;
neutralThrustEst.correction = 0.0f;
neutralThrustEst.min = 0.0f;
neutralThrustEst.max = 0.0f;
pathStatus.path_time = 0.0f;
}
static uint8_t updateAutoPilotByFrameType()
{
FrameType_t frameType = GetCurrentFrameType();
if (frameType == FRAME_TYPE_CUSTOM || frameType == FRAME_TYPE_GROUND) {
switch (vtolPathFollowerSettings.TreatCustomCraftAs) {
case VTOLPATHFOLLOWERSETTINGS_TREATCUSTOMCRAFTAS_FIXEDWING:
frameType = FRAME_TYPE_FIXED_WING;
break;
case VTOLPATHFOLLOWERSETTINGS_TREATCUSTOMCRAFTAS_VTOL:
frameType = FRAME_TYPE_MULTIROTOR;
break;
}
}
switch (frameType) {
case FRAME_TYPE_MULTIROTOR:
case FRAME_TYPE_HELI:
updatePeriod = vtolPathFollowerSettings.UpdatePeriod;
return updateAutoPilotVtol();
break;
case FRAME_TYPE_FIXED_WING:
default:
updatePeriod = fixedWingPathFollowerSettings.UpdatePeriod;
return updateAutoPilotFixedWing();
break;
}
}
/**
* fixed wing autopilot:
* straight forward:
* 1. update path velocity for limited motion crafts
* 2. update attitude according to default fixed wing pathfollower algorithm
*/
static uint8_t updateAutoPilotFixedWing()
{
pid_configure(&global.PIDposH[0], fixedWingPathFollowerSettings.HorizontalPosP, 0.0f, 0.0f, 0.0f);
pid_configure(&global.PIDposH[1], fixedWingPathFollowerSettings.HorizontalPosP, 0.0f, 0.0f, 0.0f);
pid_configure(&global.PIDposV, fixedWingPathFollowerSettings.VerticalPosP, 0.0f, 0.0f, 0.0f);
updatePathVelocity(fixedWingPathFollowerSettings.CourseFeedForward, true);
return updateFixedDesiredAttitude();
}
/**
* vtol autopilot
* use hover capable algorithm with unlimeted movement calculation. if that fails (flyaway situation due to compass failure)
* fall back to emergency fallback autopilot to keep minimum amount of flight control
*/
static uint8_t updateAutoPilotVtol()
{
enum { RETURN_0 = 0, RETURN_1 = 1, RETURN_RESULT } returnmode;
enum { FOLLOWER_REGULAR, FOLLOWER_FALLBACK } followermode;
uint8_t result = 0;
// decide on behaviour based on settings and system state
if (global.vtolEmergencyFallbackSwitch) {
returnmode = RETURN_0;
followermode = FOLLOWER_FALLBACK;
} else {
if (vtolPathFollowerSettings.FlyawayEmergencyFallback == VTOLPATHFOLLOWERSETTINGS_FLYAWAYEMERGENCYFALLBACK_ALWAYS) {
returnmode = RETURN_1;
followermode = FOLLOWER_FALLBACK;
} else {
returnmode = RETURN_RESULT;
followermode = FOLLOWER_REGULAR;
}
}
// vertical positon control PID loops works the same in both regular and fallback modes, setup according to settings
pid_configure(&global.PIDposV, vtolPathFollowerSettings.VerticalPosP, 0.0f, 0.0f, 0.0f);
switch (followermode) {
case FOLLOWER_REGULAR:
{
// horizontal position control PID loop works according to settings in regular mode, allowing integral terms
pid_configure(&global.PIDposH[0], vtolPathFollowerSettings.HorizontalPosP, 0.0f, 0.0f, 0.0f);
pid_configure(&global.PIDposH[1], vtolPathFollowerSettings.HorizontalPosP, 0.0f, 0.0f, 0.0f);
updatePathVelocity(vtolPathFollowerSettings.CourseFeedForward, false);
// yaw behaviour is configurable in vtolpathfollower, select yaw control algorithm
bool yaw_attitude = true;
float yaw = 0.0f;
if (pathDesired.Mode == PATHDESIRED_MODE_BRAKE) {
yaw_attitude = false;
} else {
switch (vtolPathFollowerSettings.YawControl) {
case VTOLPATHFOLLOWERSETTINGS_YAWCONTROL_MANUAL:
yaw_attitude = false;
break;
case VTOLPATHFOLLOWERSETTINGS_YAWCONTROL_TAILIN:
yaw = updateTailInBearing();
break;
case VTOLPATHFOLLOWERSETTINGS_YAWCONTROL_MOVEMENTDIRECTION:
yaw = updateCourseBearing();
break;
case VTOLPATHFOLLOWERSETTINGS_YAWCONTROL_PATHDIRECTION:
yaw = updatePathBearing();
break;
case VTOLPATHFOLLOWERSETTINGS_YAWCONTROL_POI:
yaw = updatePOIBearing();
break;
}
}
result = updateVtolDesiredAttitude(yaw_attitude, yaw);
if (!result) {
if (pathDesired.Mode == PATHDESIRED_MODE_BRAKE) {
plan_setup_assistedcontrol(true); // revert braking to position hold, user can always stick override
} else if (vtolPathFollowerSettings.FlyawayEmergencyFallback != VTOLPATHFOLLOWERSETTINGS_FLYAWAYEMERGENCYFALLBACK_DISABLED) {
// switch to emergency follower if follower indicates problems
global.vtolEmergencyFallbackSwitch = true;
}
}
}
break;
case FOLLOWER_FALLBACK:
{
// fallback loop only cares about intended horizontal flight direction, simplify control behaviour accordingly
pid_configure(&global.PIDposH[0], 1.0f, 0.0f, 0.0f, 0.0f);
pid_configure(&global.PIDposH[1], 1.0f, 0.0f, 0.0f, 0.0f);
updatePathVelocity(vtolPathFollowerSettings.CourseFeedForward, true);
// emergency follower has no return value
updateVtolDesiredAttitudeEmergencyFallback();
}
break;
}
// Brake mode end condition checks
if (pathDesired.Mode == PATHDESIRED_MODE_BRAKE) {
bool exit_brake = false;
VelocityStateData velocityState;
if (pathStatus.path_time > pathDesired.ModeParameters[PATHDESIRED_MODEPARAMETER_BRAKE_TIMEOUT]) { // enter hold on timeout
pathSummary.brake_exit_reason = PATHSUMMARY_BRAKE_EXIT_REASON_TIMEOUT;
exit_brake = true;
} else if (pathStatus.fractional_progress > BRAKE_FRACTIONALPROGRESS_STARTVELOCITYCHECK) {
VelocityStateGet(&velocityState);
if (fabsf(velocityState.East) < BRAKE_EXIT_VELOCITY_LIMIT && fabsf(velocityState.North) < BRAKE_EXIT_VELOCITY_LIMIT) {
pathSummary.brake_exit_reason = PATHSUMMARY_BRAKE_EXIT_REASON_PATHCOMPLETED;
exit_brake = true;
}
}
if (exit_brake) {
// Calculate the distance error between the originally desired
// stopping point and the actual brake-exit point.
PositionStateData p;
PositionStateGet(&p);
float north_offset = pathDesired.End.North - p.North;
float east_offset = pathDesired.End.East - p.East;
float down_offset = pathDesired.End.Down - p.Down;
pathSummary.brake_distance_offset = sqrtf(north_offset * north_offset + east_offset * east_offset + down_offset * down_offset);
pathSummary.time_remaining = pathDesired.ModeParameters[PATHDESIRED_MODEPARAMETER_BRAKE_TIMEOUT] - pathStatus.path_time;
pathSummary.fractional_progress = pathStatus.fractional_progress;
float cur_velocity = velocityState.North * velocityState.North + velocityState.East * velocityState.East + velocityState.Down * velocityState.Down;
cur_velocity = sqrtf(cur_velocity);
pathSummary.decelrate = (pathDesired.StartingVelocity - cur_velocity) / pathStatus.path_time;
pathSummary.brakeRateActualDesiredRatio = pathSummary.decelrate / vtolPathFollowerSettings.BrakeRate;
pathSummary.velocityIntoHold = cur_velocity;
pathSummary.UID = pathStatus.UID;
PathSummarySet(&pathSummary);
plan_setup_assistedcontrol(true); // braking timeout true
// having re-entered hold allow reassessment of neutral thrust
neutralThrustEst.have_correction = false;
}
}
switch (returnmode) {
case RETURN_RESULT:
return result;
default:
// returns either 0 or 1 according to enum definition above
return returnmode;
}
}
/**
* Compute bearing of current takeoff location
*/
static float updateTailInBearing()
{
PositionStateData p;
PositionStateGet(&p);
TakeOffLocationData t;
TakeOffLocationGet(&t);
// atan2f always returns in between + and - 180 degrees
return RAD2DEG(atan2f(p.East - t.East, p.North - t.North));
}
/**
* Compute bearing of current movement direction
*/
static float updateCourseBearing()
{
VelocityStateData v;
VelocityStateGet(&v);
// atan2f always returns in between + and - 180 degrees
return RAD2DEG(atan2f(v.East, v.North));
}
/**
* Compute bearing of current path direction
*/
static float updatePathBearing()
{
PositionStateData positionState;
PositionStateGet(&positionState);
float cur[3] = { positionState.North,
positionState.East,
positionState.Down };
struct path_status progress;
path_progress(&pathDesired, cur, &progress);
// atan2f always returns in between + and - 180 degrees
return RAD2DEG(atan2f(progress.path_vector[1], progress.path_vector[0]));
}
/**
* Compute bearing between current position and POI
*/
static float updatePOIBearing()
{
PoiLocationData poi;
PoiLocationGet(&poi);
PositionStateData positionState;
PositionStateGet(&positionState);
const float dT = updatePeriod / 1000.0f;
float dLoc[3];
float yaw = 0;
/*float elevation = 0;*/
dLoc[0] = positionState.North - poi.North;
dLoc[1] = positionState.East - poi.East;
dLoc[2] = positionState.Down - poi.Down;
if (dLoc[1] < 0) {
yaw = RAD2DEG(atan2f(dLoc[1], dLoc[0])) + 180.0f;
} else {
yaw = RAD2DEG(atan2f(dLoc[1], dLoc[0])) - 180.0f;
}
ManualControlCommandData manualControlData;
ManualControlCommandGet(&manualControlData);
float pathAngle = 0;
if (manualControlData.Roll > DEADBAND_HIGH) {
pathAngle = -(manualControlData.Roll - DEADBAND_HIGH) * dT * 300.0f;
} else if (manualControlData.Roll < DEADBAND_LOW) {
pathAngle = -(manualControlData.Roll - DEADBAND_LOW) * dT * 300.0f;
}
return yaw + (pathAngle / 2.0f);
}
/**
* process POI control logic TODO: this should most likely go into manualcontrol!!!!
* TODO: the whole process of POI handling likely needs cleanup and rethinking, might be broken since manualcontrol was refactored currently
**/
static void processPOI()
{
const float dT = updatePeriod / 1000.0f;
PositionStateData positionState;
PositionStateGet(&positionState);
// TODO put commented out camera feature code back in place either
// permanently or optionally or remove it
// CameraDesiredData cameraDesired;
// CameraDesiredGet(&cameraDesired);
StabilizationDesiredData stabDesired;
StabilizationDesiredGet(&stabDesired);
PoiLocationData poi;
PoiLocationGet(&poi);
float dLoc[3];
float yaw = 0;
// TODO camera feature
/*float elevation = 0;*/
dLoc[0] = positionState.North - poi.North;
dLoc[1] = positionState.East - poi.East;
dLoc[2] = positionState.Down - poi.Down;
if (dLoc[1] < 0) {
yaw = RAD2DEG(atan2f(dLoc[1], dLoc[0])) + 180.0f;
} else {
yaw = RAD2DEG(atan2f(dLoc[1], dLoc[0])) - 180.0f;
}
// distance
float distance = sqrtf(powf(dLoc[0], 2.0f) + powf(dLoc[1], 2.0f));
ManualControlCommandData manualControlData;
ManualControlCommandGet(&manualControlData);
float changeRadius = 0;
// Move closer or further, radially
if (manualControlData.Pitch > DEADBAND_HIGH) {
changeRadius = (manualControlData.Pitch - DEADBAND_HIGH) * dT * 100.0f;
} else if (manualControlData.Pitch < DEADBAND_LOW) {
changeRadius = (manualControlData.Pitch - DEADBAND_LOW) * dT * 100.0f;
}
// move along circular path
float pathAngle = 0;
if (manualControlData.Roll > DEADBAND_HIGH) {
pathAngle = -(manualControlData.Roll - DEADBAND_HIGH) * dT * 300.0f;
} else if (manualControlData.Roll < DEADBAND_LOW) {
pathAngle = -(manualControlData.Roll - DEADBAND_LOW) * dT * 300.0f;
} else if (manualControlData.Roll >= DEADBAND_LOW && manualControlData.Roll <= DEADBAND_HIGH) {
// change radius only when not circling
global.poiRadius = distance + changeRadius;
}
// don't try to move any closer
if (global.poiRadius >= 3.0f || changeRadius > 0) {
if (fabsf(pathAngle) > 0.0f || fabsf(changeRadius) > 0.0f) {
pathDesired.End.North = poi.North + (global.poiRadius * cosf(DEG2RAD(pathAngle + yaw - 180.0f)));
pathDesired.End.East = poi.East + (global.poiRadius * sinf(DEG2RAD(pathAngle + yaw - 180.0f)));
pathDesired.StartingVelocity = 1.0f;
pathDesired.EndingVelocity = 0.0f;
pathDesired.Mode = PATHDESIRED_MODE_FLYENDPOINT;
PathDesiredSet(&pathDesired);
}
}
// not above
if (distance >= 3.0f) {
// TODO camera feature
// You can feed this into camerastabilization
/*elevation = RAD2DEG(atan2f(dLoc[2],distance));*/
// cameraDesired.Yaw=yaw;
// cameraDesired.PitchOrServo2=elevation;
// CameraDesiredSet(&cameraDesired);
}
}
static void updateBrakeVelocity(float startingVelocity, float dT, float brakeRate, float currentVelocity, float *updatedVelocity)
{
if (startingVelocity >= 0.0f) {
*updatedVelocity = startingVelocity - dT * brakeRate;
if (*updatedVelocity > currentVelocity) {
*updatedVelocity = currentVelocity;
}
if (*updatedVelocity < 0.0f) {
*updatedVelocity = 0.0f;
}
} else {
*updatedVelocity = startingVelocity + dT * brakeRate;
if (*updatedVelocity < currentVelocity) {
*updatedVelocity = currentVelocity;
}
if (*updatedVelocity > 0.0f) {
*updatedVelocity = 0.0f;
}
}
}
/**
* Compute desired velocity from the current position and path
*/
static void updatePathVelocity(float kFF, bool limited)
{
PositionStateData positionState;
PositionStateGet(&positionState);
VelocityStateData velocityState;
VelocityStateGet(&velocityState);
VelocityDesiredData velocityDesired;
const float dT = updatePeriod / 1000.0f;
if (pathDesired.Mode == PATHDESIRED_MODE_BRAKE) {
float brakeRate = vtolPathFollowerSettings.BrakeRate;
if (brakeRate < BRAKE_RATE_MINIMUM) {
brakeRate = BRAKE_RATE_MINIMUM; // set a minimum to avoid a divide by zero potential below
}
updateBrakeVelocity(pathDesired.ModeParameters[PATHDESIRED_MODEPARAMETER_BRAKE_STARTVELOCITYVECTOR_NORTH], pathStatus.path_time, brakeRate, velocityState.North, &velocityDesired.North);
updateBrakeVelocity(pathDesired.ModeParameters[PATHDESIRED_MODEPARAMETER_BRAKE_STARTVELOCITYVECTOR_EAST], pathStatus.path_time, brakeRate, velocityState.East, &velocityDesired.East);
updateBrakeVelocity(pathDesired.ModeParameters[PATHDESIRED_MODEPARAMETER_BRAKE_STARTVELOCITYVECTOR_DOWN], pathStatus.path_time, brakeRate, velocityState.Down, &velocityDesired.Down);
float cur_velocity = velocityState.North * velocityState.North + velocityState.East * velocityState.East + velocityState.Down * velocityState.Down;
cur_velocity = sqrtf(cur_velocity);
float desired_velocity = velocityDesired.North * velocityDesired.North + velocityDesired.East * velocityDesired.East + velocityDesired.Down * velocityDesired.Down;
desired_velocity = sqrtf(desired_velocity);
// update pathstatus
pathStatus.error = cur_velocity - desired_velocity;
pathStatus.fractional_progress = 1.0f;
if (pathDesired.StartingVelocity > 0.0f) {
pathStatus.fractional_progress = (pathDesired.StartingVelocity - cur_velocity) / pathDesired.StartingVelocity;
// sometimes current velocity can exceed starting velocity due to initial acceleration
if (pathStatus.fractional_progress < 0.0f) {
pathStatus.fractional_progress = 0.0f;
}
}
pathStatus.path_direction_north = velocityDesired.North;
pathStatus.path_direction_east = velocityDesired.East;
pathStatus.path_direction_down = velocityDesired.Down;
pathStatus.correction_direction_north = velocityDesired.North - velocityState.North;
pathStatus.correction_direction_east = velocityDesired.East - velocityState.East;
pathStatus.correction_direction_down = velocityDesired.Down - velocityState.Down;
} else {
// look ahead kFF seconds
float cur[3] = { positionState.North + (velocityState.North * kFF),
positionState.East + (velocityState.East * kFF),
positionState.Down + (velocityState.Down * kFF) };
struct path_status progress;
path_progress(&pathDesired, cur, &progress);
// calculate velocity - can be zero if waypoints are too close
velocityDesired.North = progress.path_vector[0];
velocityDesired.East = progress.path_vector[1];
velocityDesired.Down = progress.path_vector[2];
if (limited &&
// if a plane is crossing its desired flightpath facing the wrong way (away from flight direction)
// it would turn towards the flightpath to get on its desired course. This however would reverse the correction vector
// once it crosses the flightpath again, which would make it again turn towards the flightpath (but away from its desired heading)
// leading to an S-shape snake course the wrong way
// this only happens especially if HorizontalPosP is too high, as otherwise the angle between velocity desired and path_direction won't
// turn steep unless there is enough space complete the turn before crossing the flightpath
// in this case the plane effectively needs to be turned around
// indicators:
// difference between correction_direction and velocitystate >90 degrees and
// difference between path_direction and velocitystate >90 degrees ( 4th sector, facing away from everything )
// fix: ignore correction, steer in path direction until the situation has become better (condition doesn't apply anymore)
// calculating angles < 90 degrees through dot products
(vector_lengthf(progress.path_vector, 2) > 1e-6f) &&
((progress.path_vector[0] * velocityState.North + progress.path_vector[1] * velocityState.East) < 0.0f) &&
((progress.correction_vector[0] * velocityState.North + progress.correction_vector[1] * velocityState.East) < 0.0f)) {
;
} else {
// calculate correction
velocityDesired.North += pid_apply(&global.PIDposH[0], progress.correction_vector[0], dT);
velocityDesired.East += pid_apply(&global.PIDposH[1], progress.correction_vector[1], dT);
}
velocityDesired.Down += pid_apply(&global.PIDposV, progress.correction_vector[2], dT);
// update pathstatus
pathStatus.error = progress.error;
pathStatus.fractional_progress = progress.fractional_progress;
pathStatus.path_direction_north = progress.path_vector[0];
pathStatus.path_direction_east = progress.path_vector[1];
pathStatus.path_direction_down = progress.path_vector[2];
pathStatus.correction_direction_north = progress.correction_vector[0];
pathStatus.correction_direction_east = progress.correction_vector[1];
pathStatus.correction_direction_down = progress.correction_vector[2];
}
VelocityDesiredSet(&velocityDesired);
}
/**
* Compute desired attitude from the desired velocity for fixed wing craft
*/
static uint8_t updateFixedDesiredAttitude()
{
uint8_t result = 1;
const float dT = updatePeriod / 1000.0f; // Convert from [ms] to [s]
VelocityDesiredData velocityDesired;
VelocityStateData velocityState;
StabilizationDesiredData stabDesired;
AttitudeStateData attitudeState;
FixedWingPathFollowerStatusData fixedWingPathFollowerStatus;
AirspeedStateData airspeedState;
SystemSettingsData systemSettings;
float groundspeedProjection;
float indicatedAirspeedState;
float indicatedAirspeedDesired;
float airspeedError;
float pitchCommand;
float descentspeedDesired;
float descentspeedError;
float powerCommand;
float airspeedVector[2];
float fluidMovement[2];
float courseComponent[2];
float courseError;
float courseCommand;
FixedWingPathFollowerStatusGet(&fixedWingPathFollowerStatus);
VelocityStateGet(&velocityState);
StabilizationDesiredGet(&stabDesired);
VelocityDesiredGet(&velocityDesired);
AttitudeStateGet(&attitudeState);
AirspeedStateGet(&airspeedState);
SystemSettingsGet(&systemSettings);
/**
* Compute speed error and course
*/
// missing sensors for airspeed-direction we have to assume within
// reasonable error that measured airspeed is actually the airspeed
// component in forward pointing direction
// airspeedVector is normalized
airspeedVector[0] = cos_lookup_deg(attitudeState.Yaw);
airspeedVector[1] = sin_lookup_deg(attitudeState.Yaw);
// current ground speed projected in forward direction
groundspeedProjection = velocityState.North * airspeedVector[0] + velocityState.East * airspeedVector[1];
// note that airspeedStateBias is ( calibratedAirspeed - groundspeedProjection ) at the time of measurement,
// but thanks to accelerometers, groundspeedProjection reacts faster to changes in direction
// than airspeed and gps sensors alone
indicatedAirspeedState = groundspeedProjection + indicatedAirspeedStateBias;
// fluidMovement is a vector describing the aproximate movement vector of
// the surrounding fluid in 2d space (aka wind vector)
fluidMovement[0] = velocityState.North - (indicatedAirspeedState * airspeedVector[0]);
fluidMovement[1] = velocityState.East - (indicatedAirspeedState * airspeedVector[1]);
// calculate the movement vector we need to fly to reach velocityDesired -
// taking fluidMovement into account
courseComponent[0] = velocityDesired.North - fluidMovement[0];
courseComponent[1] = velocityDesired.East - fluidMovement[1];
indicatedAirspeedDesired = boundf(sqrtf(courseComponent[0] * courseComponent[0] + courseComponent[1] * courseComponent[1]),
fixedWingPathFollowerSettings.HorizontalVelMin,
fixedWingPathFollowerSettings.HorizontalVelMax);
// if we could fly at arbitrary speeds, we'd just have to move towards the
// courseComponent vector as previously calculated and we'd be fine
// unfortunately however we are bound by min and max air speed limits, so
// we need to recalculate the correct course to meet at least the
// velocityDesired vector direction at our current speed
// this overwrites courseComponent
bool valid = correctCourse(courseComponent, (float *)&velocityDesired.North, fluidMovement, indicatedAirspeedDesired);
// Error condition: wind speed too high, we can't go where we want anymore
fixedWingPathFollowerStatus.Errors.Wind = 0;
if ((!valid) &&
fixedWingPathFollowerSettings.Safetymargins.Wind > 0.5f) { // alarm switched on
fixedWingPathFollowerStatus.Errors.Wind = 1;
result = 0;
}
// Airspeed error
airspeedError = indicatedAirspeedDesired - indicatedAirspeedState;
// Vertical speed error
descentspeedDesired = boundf(
velocityDesired.Down,
-fixedWingPathFollowerSettings.VerticalVelMax,
fixedWingPathFollowerSettings.VerticalVelMax);
descentspeedError = descentspeedDesired - velocityState.Down;
// Error condition: plane too slow or too fast
fixedWingPathFollowerStatus.Errors.Highspeed = 0;
fixedWingPathFollowerStatus.Errors.Lowspeed = 0;
if (indicatedAirspeedState > systemSettings.AirSpeedMax * fixedWingPathFollowerSettings.Safetymargins.Overspeed) {
fixedWingPathFollowerStatus.Errors.Overspeed = 1;
result = 0;
}
if (indicatedAirspeedState > fixedWingPathFollowerSettings.HorizontalVelMax * fixedWingPathFollowerSettings.Safetymargins.Highspeed) {
fixedWingPathFollowerStatus.Errors.Highspeed = 1;
result = 0;
}
if (indicatedAirspeedState < fixedWingPathFollowerSettings.HorizontalVelMin * fixedWingPathFollowerSettings.Safetymargins.Lowspeed) {
fixedWingPathFollowerStatus.Errors.Lowspeed = 1;
result = 0;
}
if (indicatedAirspeedState < systemSettings.AirSpeedMin * fixedWingPathFollowerSettings.Safetymargins.Stallspeed) {
fixedWingPathFollowerStatus.Errors.Stallspeed = 1;
result = 0;
}
/**
* Compute desired thrust command
*/
// Compute the cross feed from vertical speed to pitch, with saturation
float speedErrorToPowerCommandComponent = boundf(
(airspeedError / fixedWingPathFollowerSettings.HorizontalVelMin) * fixedWingPathFollowerSettings.AirspeedToPowerCrossFeed.Kp,
-fixedWingPathFollowerSettings.AirspeedToPowerCrossFeed.Max,
fixedWingPathFollowerSettings.AirspeedToPowerCrossFeed.Max
);
// Compute final thrust response
powerCommand = pid_apply(&global.PIDpower, -descentspeedError, dT) +
speedErrorToPowerCommandComponent;
// Output internal state to telemetry
fixedWingPathFollowerStatus.Error.Power = descentspeedError;
fixedWingPathFollowerStatus.ErrorInt.Power = global.PIDpower.iAccumulator;
fixedWingPathFollowerStatus.Command.Power = powerCommand;
// set thrust
stabDesired.Thrust = boundf(fixedWingPathFollowerSettings.ThrustLimit.Neutral + powerCommand,
fixedWingPathFollowerSettings.ThrustLimit.Min,
fixedWingPathFollowerSettings.ThrustLimit.Max);
// Error condition: plane cannot hold altitude at current speed.
fixedWingPathFollowerStatus.Errors.Lowpower = 0;
if (fixedWingPathFollowerSettings.ThrustLimit.Neutral + powerCommand >= fixedWingPathFollowerSettings.ThrustLimit.Max && // thrust at maximum
velocityState.Down > 0.0f && // we ARE going down
descentspeedDesired < 0.0f && // we WANT to go up
airspeedError > 0.0f && // we are too slow already
fixedWingPathFollowerSettings.Safetymargins.Lowpower > 0.5f) { // alarm switched on
fixedWingPathFollowerStatus.Errors.Lowpower = 1;
result = 0;
}
// Error condition: plane keeps climbing despite minimum thrust (opposite of above)
fixedWingPathFollowerStatus.Errors.Highpower = 0;
if (fixedWingPathFollowerSettings.ThrustLimit.Neutral + powerCommand <= fixedWingPathFollowerSettings.ThrustLimit.Min && // thrust at minimum
velocityState.Down < 0.0f && // we ARE going up
descentspeedDesired > 0.0f && // we WANT to go down
airspeedError < 0.0f && // we are too fast already
fixedWingPathFollowerSettings.Safetymargins.Highpower > 0.5f) { // alarm switched on
fixedWingPathFollowerStatus.Errors.Highpower = 1;
result = 0;
}
/**
* Compute desired pitch command
*/
// Compute the cross feed from vertical speed to pitch, with saturation
float verticalSpeedToPitchCommandComponent = boundf(-descentspeedError * fixedWingPathFollowerSettings.VerticalToPitchCrossFeed.Kp,
-fixedWingPathFollowerSettings.VerticalToPitchCrossFeed.Max,
fixedWingPathFollowerSettings.VerticalToPitchCrossFeed.Max
);
// Compute the pitch command as err*Kp + errInt*Ki + X_feed.
pitchCommand = -pid_apply(&global.PIDspeed, airspeedError, dT) + verticalSpeedToPitchCommandComponent;
fixedWingPathFollowerStatus.Error.Speed = airspeedError;
fixedWingPathFollowerStatus.ErrorInt.Speed = global.PIDspeed.iAccumulator;
fixedWingPathFollowerStatus.Command.Speed = pitchCommand;
stabDesired.Pitch = boundf(fixedWingPathFollowerSettings.PitchLimit.Neutral + pitchCommand,
fixedWingPathFollowerSettings.PitchLimit.Min,
fixedWingPathFollowerSettings.PitchLimit.Max);
// Error condition: high speed dive
fixedWingPathFollowerStatus.Errors.Pitchcontrol = 0;
if (fixedWingPathFollowerSettings.PitchLimit.Neutral + pitchCommand >= fixedWingPathFollowerSettings.PitchLimit.Max && // pitch demand is full up
velocityState.Down > 0.0f && // we ARE going down
descentspeedDesired < 0.0f && // we WANT to go up
airspeedError < 0.0f && // we are too fast already
fixedWingPathFollowerSettings.Safetymargins.Pitchcontrol > 0.5f) { // alarm switched on
fixedWingPathFollowerStatus.Errors.Pitchcontrol = 1;
result = 0;
}
/**
* Compute desired roll command
*/
courseError = RAD2DEG(atan2f(courseComponent[1], courseComponent[0])) - attitudeState.Yaw;
if (courseError < -180.0f) {
courseError += 360.0f;
}
if (courseError > 180.0f) {
courseError -= 360.0f;
}
// overlap calculation. Theres a dead zone behind the craft where the
// counter-yawing of some craft while rolling could render a desired right
// turn into a desired left turn. Making the turn direction based on
// current roll angle keeps the plane committed to a direction once chosen
if (courseError < -180.0f + (fixedWingPathFollowerSettings.ReverseCourseOverlap * 0.5f)
&& attitudeState.Roll > 0.0f) {
courseError += 360.0f;
}
if (courseError > 180.0f - (fixedWingPathFollowerSettings.ReverseCourseOverlap * 0.5f)
&& attitudeState.Roll < 0.0f) {
courseError -= 360.0f;
}
courseCommand = pid_apply(&global.PIDcourse, courseError, dT);
fixedWingPathFollowerStatus.Error.Course = courseError;
fixedWingPathFollowerStatus.ErrorInt.Course = global.PIDcourse.iAccumulator;
fixedWingPathFollowerStatus.Command.Course = courseCommand;
stabDesired.Roll = boundf(fixedWingPathFollowerSettings.RollLimit.Neutral +
courseCommand,
fixedWingPathFollowerSettings.RollLimit.Min,
fixedWingPathFollowerSettings.RollLimit.Max);
// TODO: find a check to determine loss of directional control. Likely needs some check of derivative
/**
* Compute desired yaw command
*/
// TODO implement raw control mode for yaw and base on Accels.Y
stabDesired.Yaw = 0.0f;
stabDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_MANUAL;
stabDesired.StabilizationMode.Thrust = STABILIZATIONDESIRED_STABILIZATIONMODE_MANUAL;
StabilizationDesiredSet(&stabDesired);
FixedWingPathFollowerStatusSet(&fixedWingPathFollowerStatus);
return result;
}
/**
* Function to calculate course vector C based on airspeed s, fluid movement F
* and desired movement vector V
* parameters in: V,F,s
* parameters out: C
* returns true if a valid solution could be found for V,F,s, false if not
* C will be set to a best effort attempt either way
*/
static bool correctCourse(float *C, float *V, float *F, float s)
{
// Approach:
// Let Sc be a circle around origin marking possible movement vectors
// of the craft with airspeed s (all possible options for C)
// Let Vl be a line through the origin along movement vector V where fr any
// point v on line Vl v = k * (V / |V|) = k' * V
// Let Wl be a line parallel to Vl where for any point v on line Vl exists
// a point w on WL with w = v - F
// Then any intersection between circle Sc and line Wl represents course
// vector which would result in a movement vector
// V' = k * ( V / |V|) = k' * V
// If there is no intersection point, S is insufficient to compensate
// for F and we can only try to fly in direction of V (thus having wind drift
// but at least making progress orthogonal to wind)
s = fabsf(s);
float f = vector_lengthf(F, 2);
// normalize Cn=V/|V|, |V| must be >0
float v = vector_lengthf(V, 2);
if (v < 1e-6f) {
// if |V|=0, we aren't supposed to move, turn into the wind
// (this allows hovering)
C[0] = -F[0];
C[1] = -F[1];
// if desired airspeed matches fluidmovement a hover is actually
// intended so return true
return fabsf(f - s) < 1e-3f;
}
float Vn[2] = { V[0] / v, V[1] / v };
// project F on V
float fp = F[0] * Vn[0] + F[1] * Vn[1];
// find component Fo of F that is orthogonal to V
// (which is exactly the distance between Vl and Wl)
float Fo[2] = { F[0] - (fp * Vn[0]), F[1] - (fp * Vn[1]) };
float fo2 = Fo[0] * Fo[0] + Fo[1] * Fo[1];
// find k where k * Vn = C - Fo
// |C|=s is the hypothenuse in any rectangular triangle formed by k * Vn and Fo
// so k^2 + fo^2 = s^2 (since |Vn|=1)
float k2 = s * s - fo2;
if (k2 <= -1e-3f) {
// there is no solution, we will be drifted off either way
// fallback: fly stupidly in direction of V and hope for the best
C[0] = V[0];
C[1] = V[1];
return false;
} else if (k2 <= 1e-3f) {
// there is exactly one solution: -Fo
C[0] = -Fo[0];
C[1] = -Fo[1];
return true;
}
// we have two possible solutions k positive and k negative as there are
// two intersection points between Wl and Sc
// which one is better? two criteria:
// 1. we MUST move in the right direction, if any k leads to -v its invalid
// 2. we should minimize the speed error
float k = sqrt(k2);
float C1[2] = { -k * Vn[0] - Fo[0], -k * Vn[1] - Fo[1] };
float C2[2] = { k *Vn[0] - Fo[0], k * Vn[1] - Fo[1] };
// project C+F on Vn to find signed resulting movement vector length
float vp1 = (C1[0] + F[0]) * Vn[0] + (C1[1] + F[1]) * Vn[1];
float vp2 = (C2[0] + F[0]) * Vn[0] + (C2[1] + F[1]) * Vn[1];
if (vp1 >= 0.0f && fabsf(v - vp1) < fabsf(v - vp2)) {
// in this case the angle between course and resulting movement vector
// is greater than 90 degrees - so we actually fly backwards
C[0] = C1[0];
C[1] = C1[1];
return true;
}
C[0] = C2[0];
C[1] = C2[1];
if (vp2 >= 0.0f) {
// in this case the angle between course and movement vector is less than
// 90 degrees, but we do move in the right direction
return true;
} else {
// in this case we actually get driven in the opposite direction of V
// with both solutions for C
// this might be reached in headwind stronger than maximum allowed
// airspeed.
return false;
}
}
/**
* Compute desired attitude from the desired velocity
*
* Takes in @ref NedState which has the acceleration in the
* NED frame as the feedback term and then compares the
* @ref VelocityState against the @ref VelocityDesired
*/
static int8_t updateVtolDesiredAttitude(bool yaw_attitude, float yaw_direction)
{
const float dT = updatePeriod / 1000.0f;
uint8_t result = 1;
bool manual_thrust = false;
VelocityDesiredData velocityDesired;
VelocityStateData velocityState;
StabilizationDesiredData stabDesired;
AttitudeStateData attitudeState;
StabilizationBankData stabSettings;
SystemSettingsData systemSettings;
VtolSelfTuningStatsData vtolSelfTuningStats;
float northError;
float northCommand;
float eastError;
float eastCommand;
float downError;
float downCommand;
SystemSettingsGet(&systemSettings);
VelocityStateGet(&velocityState);
VelocityDesiredGet(&velocityDesired);
StabilizationDesiredGet(&stabDesired);
VelocityDesiredGet(&velocityDesired);
AttitudeStateGet(&attitudeState);
StabilizationBankGet(&stabSettings);
VtolSelfTuningStatsGet(&vtolSelfTuningStats);
if (pathDesired.Mode != PATHDESIRED_MODE_BRAKE) {
// scale velocity if it is above configured maximum
// for braking, we can not help it if initial velocity was greater
float velH = sqrtf(velocityDesired.North * velocityDesired.North + velocityDesired.East * velocityDesired.East);
if (velH > vtolPathFollowerSettings.HorizontalVelMax) {
velocityDesired.North *= vtolPathFollowerSettings.HorizontalVelMax / velH;
velocityDesired.East *= vtolPathFollowerSettings.HorizontalVelMax / velH;
}
if (fabsf(velocityDesired.Down) > vtolPathFollowerSettings.VerticalVelMax) {
velocityDesired.Down *= vtolPathFollowerSettings.VerticalVelMax / fabsf(velocityDesired.Down);
}
}
// calculate the velocity errors between desired and actual
northError = velocityDesired.North - velocityState.North;
eastError = velocityDesired.East - velocityState.East;
downError = velocityDesired.Down - velocityState.Down;
// Must flip this sign
downError = -downError;
// Compute desired commands
if (pathDesired.Mode != PATHDESIRED_MODE_BRAKE) {
northCommand = pid_apply(&global.PIDvel[0], northError, dT) + velocityDesired.North * vtolPathFollowerSettings.VelocityFeedforward;
eastCommand = pid_apply(&global.PIDvel[1], eastError, dT) + velocityDesired.East * vtolPathFollowerSettings.VelocityFeedforward;
} else {
northCommand = pid_apply(&global.BrakePIDvel[0], northError, dT) + velocityDesired.North * vtolPathFollowerSettings.BrakeVelocityFeedforward;
eastCommand = pid_apply(&global.BrakePIDvel[1], eastError, dT) + velocityDesired.East * vtolPathFollowerSettings.BrakeVelocityFeedforward;
}
downCommand = pid_apply(&global.PIDvel[2], downError, dT);
if ((vtolPathFollowerSettings.ThrustControl == VTOLPATHFOLLOWERSETTINGS_THRUSTCONTROL_MANUAL &&
flightStatus.FlightModeAssist == FLIGHTSTATUS_FLIGHTMODEASSIST_NONE) ||
(flightStatus.FlightModeAssist && flightStatus.AssistedThrottleState == FLIGHTSTATUS_ASSISTEDTHROTTLESTATE_MANUAL)) {
manual_thrust = true;
}
// if auto thrust and we have not run a correction calc check for PH and stability to then run an assessment
// note that arming into this flight mode is not allowed, so assumption here is that
// we have not landed. If GPSAssist+Manual/Cruise control thrust mode is used, a user overriding the
// altitude maintaining PID will have moved the throttle state to FLIGHTSTATUS_ASSISTEDTHROTTLESTATE_MANUAL.
// In manualcontrol.c the state will stay in manual throttle until the throttle command exceeds the vtol thrust min,
// avoiding auto-takeoffs. Therefore no need to check that here.
if (!manual_thrust && neutralThrustEst.have_correction != true) {
// Assess if position hold state running. This can be normal position hold or
// another mode with assist-hold active.
bool ph_active =
((flightStatus.FlightMode == FLIGHTSTATUS_FLIGHTMODE_POSITIONHOLD &&
flightStatus.FlightModeAssist == FLIGHTSTATUS_FLIGHTMODEASSIST_NONE) ||
(flightStatus.FlightModeAssist != FLIGHTSTATUS_FLIGHTMODEASSIST_NONE &&
flightStatus.AssistedControlState == FLIGHTSTATUS_ASSISTEDCONTROLSTATE_HOLD));
bool stable = (fabsf(pathStatus.correction_direction_down) < NEUTRALTHRUST_PH_POSITIONAL_ERROR_LIMIT &&
fabsf(velocityDesired.Down) < NEUTRALTHRUST_PH_VEL_DESIRED_LIMIT &&
fabsf(velocityState.Down) < NEUTRALTHRUST_PH_VEL_STATE_LIMIT &&
fabsf(downError) < NEUTRALTHRUST_PH_VEL_ERROR_LIMIT);
if (ph_active && stable) {
if (neutralThrustEst.start_sampling) {
neutralThrustEst.count++;
// delay count for 2 seconds into hold allowing for stablisation
if (neutralThrustEst.count > NEUTRALTHRUST_START_DELAY) {
neutralThrustEst.sum += global.PIDvel[2].iAccumulator;
if (global.PIDvel[2].iAccumulator < neutralThrustEst.min) {
neutralThrustEst.min = global.PIDvel[2].iAccumulator;
}
if (global.PIDvel[2].iAccumulator > neutralThrustEst.max) {
neutralThrustEst.max = global.PIDvel[2].iAccumulator;
}
}
if (neutralThrustEst.count >= NEUTRALTHRUST_END_COUNT) {
// 6 seconds have past
// lets take an average
neutralThrustEst.average = neutralThrustEst.sum / (float)(NEUTRALTHRUST_END_COUNT - NEUTRALTHRUST_START_DELAY);
neutralThrustEst.correction = neutralThrustEst.average / 1000.0f;
global.PIDvel[2].iAccumulator -= neutralThrustEst.average;
neutralThrustEst.start_sampling = false;
neutralThrustEst.have_correction = true;
// Write a new adjustment value
// vtolSelfTuningStats.NeutralThrustOffset was incremental adjusted above
VtolSelfTuningStatsData new_vtolSelfTuningStats;
// add the average remaining i value to the
new_vtolSelfTuningStats.NeutralThrustOffset = vtolSelfTuningStats.NeutralThrustOffset + neutralThrustEst.correction;
new_vtolSelfTuningStats.NeutralThrustCorrection = neutralThrustEst.correction; // the i term thrust correction value applied
new_vtolSelfTuningStats.NeutralThrustAccumulator = global.PIDvel[2].iAccumulator; // the actual iaccumulator value after correction
new_vtolSelfTuningStats.NeutralThrustRange = neutralThrustEst.max - neutralThrustEst.min;
VtolSelfTuningStatsSet(&new_vtolSelfTuningStats);
}
} else {
// start a tick count
neutralThrustEst.start_sampling = true;
neutralThrustEst.count = 0;
neutralThrustEst.sum = 0.0f;
neutralThrustEst.max = 0.0f;
neutralThrustEst.min = 0.0f;
}
} else {
// reset sampling as we did't get 6 continuous seconds
neutralThrustEst.start_sampling = false;
}
} // else we already have a correction for this PH run
// Generally in braking the downError will be an increased altitude. We really will rely on cruisecontrol to backoff.
stabDesired.Thrust = boundf(vtolSelfTuningStats.NeutralThrustOffset + downCommand + vtolPathFollowerSettings.ThrustLimits.Neutral, vtolPathFollowerSettings.ThrustLimits.Min, vtolPathFollowerSettings.ThrustLimits.Max);
// DEBUG HACK: allow user to skew compass on purpose to see if emergency failsafe kicks in
if (vtolPathFollowerSettings.FlyawayEmergencyFallback == VTOLPATHFOLLOWERSETTINGS_FLYAWAYEMERGENCYFALLBACK_DEBUGTEST) {
attitudeState.Yaw += 120.0f;
if (attitudeState.Yaw > 180.0f) {
attitudeState.Yaw -= 360.0f;
}
}
if ( // emergency flyaway detection
( // integral already at its limit
vtolPathFollowerSettings.HorizontalVelPID.ILimit - fabsf(global.PIDvel[0].iAccumulator) < 1e-6f ||
vtolPathFollowerSettings.HorizontalVelPID.ILimit - fabsf(global.PIDvel[1].iAccumulator) < 1e-6f
) &&
// angle between desired and actual velocity >90 degrees (by dot product)
(velocityDesired.North * velocityState.North + velocityDesired.East * velocityState.East < 0.0f) &&
// quad is moving at significant speed (during flyaway it would keep speeding up)
squaref(velocityState.North) + squaref(velocityState.East) > 1.0f
) {
global.vtolEmergencyFallback += dT;
if (global.vtolEmergencyFallback >= vtolPathFollowerSettings.FlyawayEmergencyFallbackTriggerTime) {
// after emergency timeout, trigger alarm - everything else is handled by callers
// (switch to emergency algorithm, switch to emergency waypoint in pathplanner, alarms, ...)
result = 0;
}
} else {
global.vtolEmergencyFallback = 0.0f;
}
// Project the north and east command signals into the pitch and roll based on yaw. For this to behave well the
// craft should move similarly for 5 deg roll versus 5 deg pitch
float maxPitch = vtolPathFollowerSettings.MaxRollPitch;
if (pathDesired.Mode == PATHDESIRED_MODE_BRAKE) {
maxPitch = vtolPathFollowerSettings.BrakeMaxPitch;
}
stabDesired.Pitch = boundf(-northCommand * cosf(DEG2RAD(attitudeState.Yaw)) +
-eastCommand * sinf(DEG2RAD(attitudeState.Yaw)),
-maxPitch, maxPitch);
stabDesired.Roll = boundf(-northCommand * sinf(DEG2RAD(attitudeState.Yaw)) +
eastCommand * cosf(DEG2RAD(attitudeState.Yaw)),
-maxPitch, maxPitch);
ManualControlCommandData manualControl;
ManualControlCommandGet(&manualControl);
stabDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
if (yaw_attitude) {
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.Yaw = yaw_direction;
} else {
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_AXISLOCK;
stabDesired.Yaw = stabSettings.MaximumRate.Yaw * manualControl.Yaw;
}
// default thrust mode to cruise control
stabDesired.StabilizationMode.Thrust = STABILIZATIONDESIRED_STABILIZATIONMODE_CRUISECONTROL;
// when flight mode assist is active but in primary-thrust mode, the thrust mode must be set to the same as per the primary mode.
if (flightStatus.FlightModeAssist == FLIGHTSTATUS_FLIGHTMODEASSIST_GPSASSIST_PRIMARYTHRUST) {
FlightModeSettingsData settings;
FlightModeSettingsGet(&settings);
FlightModeSettingsStabilization1SettingsOptions thrustMode = FLIGHTMODESETTINGS_STABILIZATION1SETTINGS_CRUISECONTROL;
switch (flightStatus.FlightMode) {
case FLIGHTSTATUS_FLIGHTMODE_STABILIZED1:
thrustMode = settings.Stabilization1Settings.Thrust;
break;
case FLIGHTSTATUS_FLIGHTMODE_STABILIZED2:
thrustMode = settings.Stabilization2Settings.Thrust;
break;
case FLIGHTSTATUS_FLIGHTMODE_STABILIZED3:
thrustMode = settings.Stabilization3Settings.Thrust;
break;
case FLIGHTSTATUS_FLIGHTMODE_STABILIZED4:
thrustMode = settings.Stabilization4Settings.Thrust;
break;
case FLIGHTSTATUS_FLIGHTMODE_STABILIZED5:
thrustMode = settings.Stabilization5Settings.Thrust;
break;
case FLIGHTSTATUS_FLIGHTMODE_STABILIZED6:
thrustMode = settings.Stabilization6Settings.Thrust;
break;
case FLIGHTSTATUS_FLIGHTMODE_POSITIONHOLD:
// we hard code the "GPS Assisted" PostionHold to use alt-vario which
// is a more appropriate throttle mode. "GPSAssist" adds braking
// and a better throttle management to the standard Position Hold.
thrustMode = FLIGHTMODESETTINGS_STABILIZATION1SETTINGS_ALTITUDEVARIO;
break;
}
stabDesired.StabilizationMode.Thrust = thrustMode;
stabDesired.Thrust = manualControl.Thrust;
} else if (manual_thrust) {
stabDesired.Thrust = manualControl.Thrust;
}
// else thrust is set by the PID controller
StabilizationDesiredSet(&stabDesired);
return result;
}
/**
* Compute desired attitude for vtols - emergency fallback
*/
static void updateVtolDesiredAttitudeEmergencyFallback()
{
const float dT = updatePeriod / 1000.0f;
VelocityDesiredData velocityDesired;
VelocityStateData velocityState;
StabilizationDesiredData stabDesired;
float courseError;
float courseCommand;
float downError;
float downCommand;
VelocityStateGet(&velocityState);
VelocityDesiredGet(&velocityDesired);
ManualControlCommandData manualControlData;
ManualControlCommandGet(&manualControlData);
courseError = RAD2DEG(atan2f(velocityDesired.East, velocityDesired.North) - atan2f(velocityState.East, velocityState.North));
if (courseError < -180.0f) {
courseError += 360.0f;
}
if (courseError > 180.0f) {
courseError -= 360.0f;
}
courseCommand = (courseError * vtolPathFollowerSettings.EmergencyFallbackYawRate.kP);
stabDesired.Yaw = boundf(courseCommand, -vtolPathFollowerSettings.EmergencyFallbackYawRate.Max, vtolPathFollowerSettings.EmergencyFallbackYawRate.Max);
// Compute desired down command
downError = velocityDesired.Down - velocityState.Down;
// Must flip this sign
downError = -downError;
downCommand = pid_apply(&global.PIDvel[2], downError, dT);
stabDesired.Thrust = boundf(downCommand + vtolPathFollowerSettings.ThrustLimits.Neutral, vtolPathFollowerSettings.ThrustLimits.Min, vtolPathFollowerSettings.ThrustLimits.Max);
stabDesired.Roll = vtolPathFollowerSettings.EmergencyFallbackAttitude.Roll;
stabDesired.Pitch = vtolPathFollowerSettings.EmergencyFallbackAttitude.Pitch;
if (vtolPathFollowerSettings.ThrustControl == VTOLPATHFOLLOWERSETTINGS_THRUSTCONTROL_MANUAL) {
// For now override thrust with manual control. Disable at your risk, quad goes to China.
ManualControlCommandData manualControl;
ManualControlCommandGet(&manualControl);
stabDesired.Thrust = manualControl.Thrust;
}
stabDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_RATE;
stabDesired.StabilizationMode.Thrust = STABILIZATIONDESIRED_STABILIZATIONMODE_CRUISECONTROL;
StabilizationDesiredSet(&stabDesired);
}
/**
* Compute desired attitude from a fixed preset
*
*/
static void updateFixedAttitude(float *attitude)
{
StabilizationDesiredData stabDesired;
StabilizationDesiredGet(&stabDesired);
stabDesired.Roll = attitude[0];
stabDesired.Pitch = attitude[1];
stabDesired.Yaw = attitude[2];
stabDesired.Thrust = attitude[3];
stabDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_RATE;
stabDesired.StabilizationMode.Thrust = STABILIZATIONDESIRED_STABILIZATIONMODE_MANUAL;
StabilizationDesiredSet(&stabDesired);
}
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