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LibrePilot/flight/modules/FixedWingPathFollower/fixedwingpathfollower.c
Alessio Morale 0db9a9bf8d OP-1058 Add xxxGet and xxxSet functions to handle multielement fields as struct 
for example:
EKFStateVariancePSet(EKFStateVariancePData *NewP);
EKFStateVariancePGet(EKFStateVariancePData *NewP);
Also in this case array accessors are renamed as xxxArrayGet/Set:
EKFStateVariancePArraySet(float *NewP);
EKFStateVariancePArrayGet(float *NewP);

Nothing changes for anonymous items as default functions continues to deal with arrays

+review OPReview-552
2013-09-01 13:23:20 +02:00

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/**
******************************************************************************
*
* @file fixedwingpathfollower.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: ActiveWaypoint
* Input object: PositionState
* Input object: ManualControlCommand
* Output object: AttitudeDesired
*
* This module will periodically update the value of the AttitudeDesired object.
*
* The module executes in its own thread in this example.
*
* 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 "hwsettings.h"
#include "attitudestate.h"
#include "pathdesired.h" // object that will be updated by the module
#include "positionstate.h"
#include "manualcontrol.h"
#include "flightstatus.h"
#include "pathstatus.h"
#include "airspeedstate.h"
#include "fixedwingpathfollowersettings.h"
#include "fixedwingpathfollowerstatus.h"
#include "homelocation.h"
#include "stabilizationdesired.h"
#include "stabilizationsettings.h"
#include "systemsettings.h"
#include "velocitydesired.h"
#include "velocitystate.h"
#include "taskinfo.h"
#include <pios_struct_helper.h>
#include "paths.h"
#include "CoordinateConversions.h"
// Private constants
#define MAX_QUEUE_SIZE 4
#define STACK_SIZE_BYTES 1548
#define TASK_PRIORITY (tskIDLE_PRIORITY + 2)
// Private variables
static bool followerEnabled = false;
static xTaskHandle pathfollowerTaskHandle;
static PathDesiredData pathDesired;
static PathStatusData pathStatus;
static FixedWingPathFollowerSettingsData fixedwingpathfollowerSettings;
// Private functions
static void pathfollowerTask(void *parameters);
static void SettingsUpdatedCb(UAVObjEvent *ev);
static void updatePathVelocity();
static uint8_t updateFixedDesiredAttitude();
static void updateFixedAttitude();
static void airspeedStateUpdatedCb(UAVObjEvent *ev);
static float bound(float val, float min, float max);
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t FixedWingPathFollowerStart()
{
if (followerEnabled) {
// Start main task
xTaskCreate(pathfollowerTask, (signed char *)"PathFollower", STACK_SIZE_BYTES / 4, NULL, TASK_PRIORITY, &pathfollowerTaskHandle);
PIOS_TASK_MONITOR_RegisterTask(TASKINFO_RUNNING_PATHFOLLOWER, pathfollowerTaskHandle);
}
return 0;
}
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t FixedWingPathFollowerInitialize()
{
HwSettingsInitialize();
HwSettingsOptionalModulesData optionalModules;
HwSettingsOptionalModulesGet(&optionalModules);
if (optionalModules.FixedWingPathFollower == HWSETTINGS_OPTIONALMODULES_ENABLED) {
followerEnabled = true;
FixedWingPathFollowerSettingsInitialize();
FixedWingPathFollowerStatusInitialize();
PathDesiredInitialize();
PathStatusInitialize();
VelocityDesiredInitialize();
AirspeedStateInitialize();
} else {
followerEnabled = false;
}
return 0;
}
MODULE_INITCALL(FixedWingPathFollowerInitialize, FixedWingPathFollowerStart);
static float northVelIntegral = 0;
static float eastVelIntegral = 0;
static float downVelIntegral = 0;
static float courseIntegral = 0;
static float speedIntegral = 0;
static float powerIntegral = 0;
static float airspeedErrorInt = 0;
// correct speed by measured airspeed
static float indicatedAirspeedStateBias = 0;
/**
* Module thread, should not return.
*/
static void pathfollowerTask(__attribute__((unused)) void *parameters)
{
SystemSettingsData systemSettings;
FlightStatusData flightStatus;
portTickType lastUpdateTime;
AirspeedStateConnectCallback(airspeedStateUpdatedCb);
FixedWingPathFollowerSettingsConnectCallback(SettingsUpdatedCb);
PathDesiredConnectCallback(SettingsUpdatedCb);
FixedWingPathFollowerSettingsGet(&fixedwingpathfollowerSettings);
PathDesiredGet(&pathDesired);
// Main task loop
lastUpdateTime = xTaskGetTickCount();
while (1) {
// Conditions when this runs:
// 1. Must have FixedWing type airframe
// 2. Flight mode is PositionHold and PathDesired.Mode is Endpoint OR
// FlightMode is PathPlanner and PathDesired.Mode is Endpoint or Path
SystemSettingsGet(&systemSettings);
if ((systemSettings.AirframeType != SYSTEMSETTINGS_AIRFRAMETYPE_FIXEDWING) &&
(systemSettings.AirframeType != SYSTEMSETTINGS_AIRFRAMETYPE_FIXEDWINGELEVON) &&
(systemSettings.AirframeType != SYSTEMSETTINGS_AIRFRAMETYPE_FIXEDWINGVTAIL)) {
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_WARNING);
vTaskDelay(1000);
continue;
}
// Continue collecting data if not enough time
vTaskDelayUntil(&lastUpdateTime, fixedwingpathfollowerSettings.UpdatePeriod / portTICK_RATE_MS);
FlightStatusGet(&flightStatus);
PathStatusGet(&pathStatus);
uint8_t result;
// Check the combinations of flightmode and pathdesired mode
switch (flightStatus.FlightMode) {
case FLIGHTSTATUS_FLIGHTMODE_POSITIONHOLD:
case FLIGHTSTATUS_FLIGHTMODE_RETURNTOBASE:
if (pathDesired.Mode == PATHDESIRED_MODE_FLYENDPOINT) {
updatePathVelocity();
result = updateFixedDesiredAttitude();
if (result) {
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_OK);
} else {
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_WARNING);
}
} else {
AlarmsSet(SYSTEMALARMS_ALARM_GUIDANCE, SYSTEMALARMS_ALARM_ERROR);
}
break;
case FLIGHTSTATUS_FLIGHTMODE_PATHPLANNER:
pathStatus.UID = pathDesired.UID;
pathStatus.Status = PATHSTATUS_STATUS_INPROGRESS;
switch (pathDesired.Mode) {
case PATHDESIRED_MODE_FLYENDPOINT:
case PATHDESIRED_MODE_FLYVECTOR:
case PATHDESIRED_MODE_FLYCIRCLERIGHT:
case PATHDESIRED_MODE_FLYCIRCLELEFT:
updatePathVelocity();
result = updateFixedDesiredAttitude();
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;
}
break;
default:
// Be cleaner and get rid of global variables
northVelIntegral = 0;
eastVelIntegral = 0;
downVelIntegral = 0;
courseIntegral = 0;
speedIntegral = 0;
powerIntegral = 0;
break;
}
PathStatusSet(&pathStatus);
}
}
/**
* Compute desired velocity from the current position and path
*
* Takes in @ref PositionState and compares it to @ref PathDesired
* and computes @ref VelocityDesired
*/
static void updatePathVelocity()
{
PositionStateData positionState;
PositionStateGet(&positionState);
VelocityStateData velocityState;
VelocityStateGet(&velocityState);
// look ahead fixedwingpathfollowerSettings.CourseFeedForward seconds
float cur[3] = { positionState.North + (velocityState.North * fixedwingpathfollowerSettings.CourseFeedForward),
positionState.East + (velocityState.East * fixedwingpathfollowerSettings.CourseFeedForward),
positionState.Down + (velocityState.Down * fixedwingpathfollowerSettings.CourseFeedForward) };
struct path_status progress;
path_progress(cast_struct_to_array(pathDesired.Start, pathDesired.Start.North),
cast_struct_to_array(pathDesired.End, pathDesired.End.North),
cur, &progress, pathDesired.Mode);
float groundspeed;
float altitudeSetpoint;
switch (pathDesired.Mode) {
case PATHDESIRED_MODE_FLYCIRCLERIGHT:
case PATHDESIRED_MODE_DRIVECIRCLERIGHT:
case PATHDESIRED_MODE_FLYCIRCLELEFT:
case PATHDESIRED_MODE_DRIVECIRCLELEFT:
groundspeed = pathDesired.EndingVelocity;
altitudeSetpoint = pathDesired.End.Down;
break;
case PATHDESIRED_MODE_FLYENDPOINT:
case PATHDESIRED_MODE_DRIVEENDPOINT:
case PATHDESIRED_MODE_FLYVECTOR:
case PATHDESIRED_MODE_DRIVEVECTOR:
default:
groundspeed = pathDesired.StartingVelocity + (pathDesired.EndingVelocity - pathDesired.StartingVelocity) *
bound(progress.fractional_progress, 0, 1);
altitudeSetpoint = pathDesired.Start.Down + (pathDesired.End.Down - pathDesired.Start.Down) *
bound(progress.fractional_progress, 0, 1);
break;
}
// make sure groundspeed is not zero
if (groundspeed < 1e-2f) {
groundspeed = 1e-2f;
}
// calculate velocity - can be zero if waypoints are too close
VelocityDesiredData velocityDesired;
velocityDesired.North = progress.path_direction[0];
velocityDesired.East = progress.path_direction[1];
float error_speed = progress.error * fixedwingpathfollowerSettings.HorizontalPosP;
// 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 eerything )
// fix: ignore correction, steer in path direction until the situation has become better (condition doesn't apply anymore)
float angle1 = RAD2DEG(atan2f(progress.path_direction[1], progress.path_direction[0]) - atan2f(velocityState.East, velocityState.North));
float angle2 = RAD2DEG(atan2f(progress.correction_direction[1], progress.correction_direction[0]) - atan2f(velocityState.East, velocityState.North));
if (angle1 < -180.0f) {
angle1 += 360.0f;
}
if (angle1 > 180.0f) {
angle1 -= 360.0f;
}
if (angle2 < -180.0f) {
angle2 += 360.0f;
}
if (angle2 > 180.0f) {
angle2 -= 360.0f;
}
if (fabsf(angle1) >= 90.0f && fabsf(angle2) >= 90.0f) {
error_speed = 0;
}
// calculate correction - can also be zero if correction vector is 0 or no error present
velocityDesired.North += progress.correction_direction[0] * error_speed;
velocityDesired.East += progress.correction_direction[1] * error_speed;
// scale to correct length
float l = sqrtf(velocityDesired.North * velocityDesired.North + velocityDesired.East * velocityDesired.East);
velocityDesired.North *= groundspeed / l;
velocityDesired.East *= groundspeed / l;
float downError = altitudeSetpoint - positionState.Down;
velocityDesired.Down = downError * fixedwingpathfollowerSettings.VerticalPosP;
// update pathstatus
pathStatus.error = progress.error;
pathStatus.fractional_progress = progress.fractional_progress;
VelocityDesiredSet(&velocityDesired);
}
/**
* 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.Throttle = attitude[3];
stabDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_RATE;
StabilizationDesiredSet(&stabDesired);
}
/**
* 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 uint8_t updateFixedDesiredAttitude()
{
uint8_t result = 1;
float dT = fixedwingpathfollowerSettings.UpdatePeriod / 1000.0f; // Convert from [ms] to [s]
VelocityDesiredData velocityDesired;
VelocityStateData velocityState;
StabilizationDesiredData stabDesired;
AttitudeStateData attitudeState;
StabilizationSettingsData stabSettings;
FixedWingPathFollowerStatusData fixedwingpathfollowerStatus;
AirspeedStateData airspeedState;
SystemSettingsData systemSettings;
float groundspeedState;
float groundspeedDesired;
float indicatedAirspeedState;
float indicatedAirspeedDesired;
float airspeedError;
float pitchCommand;
float descentspeedDesired;
float descentspeedError;
float powerCommand;
float bearing;
float heading;
float headingError;
float course;
float courseError;
float courseCommand;
FixedWingPathFollowerStatusGet(&fixedwingpathfollowerStatus);
VelocityStateGet(&velocityState);
StabilizationDesiredGet(&stabDesired);
VelocityDesiredGet(&velocityDesired);
AttitudeStateGet(&attitudeState);
StabilizationSettingsGet(&stabSettings);
AirspeedStateGet(&airspeedState);
SystemSettingsGet(&systemSettings);
/**
* Compute speed error (required for throttle and pitch)
*/
// Current ground speed
groundspeedState = sqrtf(velocityState.East * velocityState.East + velocityState.North * velocityState.North);
// note that airspeedStateBias is ( calibratedAirspeed - groundSpeed ) at the time of measurement,
// but thanks to accelerometers, groundspeed reacts faster to changes in direction
// than airspeed and gps sensors alone
indicatedAirspeedState = groundspeedState + indicatedAirspeedStateBias;
// Desired ground speed
groundspeedDesired = sqrtf(velocityDesired.North * velocityDesired.North + velocityDesired.East * velocityDesired.East);
indicatedAirspeedDesired = bound(groundspeedDesired + indicatedAirspeedStateBias,
fixedwingpathfollowerSettings.HorizontalVelMin,
fixedwingpathfollowerSettings.HorizontalVelMax);
// Airspeed error
airspeedError = indicatedAirspeedDesired - indicatedAirspeedState;
// Vertical speed error
descentspeedDesired = bound(
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;
}
if (indicatedAirspeedState < 1e-6f) {
// prevent division by zero, abort without controlling anything. This guidance mode is not suited for takeoff or touchdown, or handling stationary planes
// also we cannot handle planes flying backwards, lets just wait until the nose drops
fixedwingpathfollowerStatus.Errors.Lowspeed = 1;
return 0;
}
/**
* Compute desired throttle command
*/
// compute saturated integral error throttle response. Make integral leaky for better performance. Approximately 30s time constant.
if (fixedwingpathfollowerSettings.PowerPI.Ki > 0) {
powerIntegral = bound(powerIntegral + -descentspeedError * dT,
-fixedwingpathfollowerSettings.PowerPI.ILimit / fixedwingpathfollowerSettings.PowerPI.Ki,
fixedwingpathfollowerSettings.PowerPI.ILimit / fixedwingpathfollowerSettings.PowerPI.Ki
) * (1.0f - 1.0f / (1.0f + 30.0f / dT));
} else { powerIntegral = 0; }
// Compute the cross feed from vertical speed to pitch, with saturation
float speedErrorToPowerCommandComponent = bound(
(airspeedError / fixedwingpathfollowerSettings.HorizontalVelMin) * fixedwingpathfollowerSettings.AirspeedToPowerCrossFeed.Kp,
-fixedwingpathfollowerSettings.AirspeedToPowerCrossFeed.Max,
fixedwingpathfollowerSettings.AirspeedToPowerCrossFeed.Max
);
// Compute final throttle response
powerCommand = -descentspeedError * fixedwingpathfollowerSettings.PowerPI.Kp +
powerIntegral * fixedwingpathfollowerSettings.PowerPI.Ki +
speedErrorToPowerCommandComponent;
// Output internal state to telemetry
fixedwingpathfollowerStatus.Error.Power = descentspeedError;
fixedwingpathfollowerStatus.ErrorInt.Power = powerIntegral;
fixedwingpathfollowerStatus.Command.Power = powerCommand;
// set throttle
stabDesired.Throttle = bound(fixedwingpathfollowerSettings.ThrottleLimit.Neutral + powerCommand,
fixedwingpathfollowerSettings.ThrottleLimit.Min,
fixedwingpathfollowerSettings.ThrottleLimit.Max);
// Error condition: plane cannot hold altitude at current speed.
fixedwingpathfollowerStatus.Errors.Lowpower = 0;
if (powerCommand >= fixedwingpathfollowerSettings.ThrottleLimit.Max && // throttle at maximum
velocityState.Down > 0 && // we ARE going down
descentspeedDesired < 0 && // we WANT to go up
airspeedError > 0 && // 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 throttle (opposite of above)
fixedwingpathfollowerStatus.Errors.Highpower = 0;
if (powerCommand >= fixedwingpathfollowerSettings.ThrottleLimit.Min && // throttle at minimum
velocityState.Down < 0 && // we ARE going up
descentspeedDesired > 0 && // we WANT to go down
airspeedError < 0 && // we are too fast already
fixedwingpathfollowerSettings.Safetymargins.Highpower > 0.5f) { // alarm switched on
fixedwingpathfollowerStatus.Errors.Highpower = 1;
result = 0;
}
/**
* Compute desired pitch command
*/
if (fixedwingpathfollowerSettings.SpeedPI.Ki > 0) {
// Integrate with saturation
airspeedErrorInt = bound(airspeedErrorInt + airspeedError * dT,
-fixedwingpathfollowerSettings.SpeedPI.ILimit / fixedwingpathfollowerSettings.SpeedPI.Ki,
fixedwingpathfollowerSettings.SpeedPI.ILimit / fixedwingpathfollowerSettings.SpeedPI.Ki);
}
// Compute the cross feed from vertical speed to pitch, with saturation
float verticalSpeedToPitchCommandComponent = bound(-descentspeedError * fixedwingpathfollowerSettings.VerticalToPitchCrossFeed.Kp,
-fixedwingpathfollowerSettings.VerticalToPitchCrossFeed.Max,
fixedwingpathfollowerSettings.VerticalToPitchCrossFeed.Max
);
// Compute the pitch command as err*Kp + errInt*Ki + X_feed.
pitchCommand = -(airspeedError * fixedwingpathfollowerSettings.SpeedPI.Kp
+ airspeedErrorInt * fixedwingpathfollowerSettings.SpeedPI.Ki
) + verticalSpeedToPitchCommandComponent;
fixedwingpathfollowerStatus.Error.Speed = airspeedError;
fixedwingpathfollowerStatus.ErrorInt.Speed = airspeedErrorInt;
fixedwingpathfollowerStatus.Command.Speed = pitchCommand;
stabDesired.Pitch = bound(fixedwingpathfollowerSettings.PitchLimit.Neutral + pitchCommand,
fixedwingpathfollowerSettings.PitchLimit.Min,
fixedwingpathfollowerSettings.PitchLimit.Max);
// Error condition: high speed dive
fixedwingpathfollowerStatus.Errors.Pitchcontrol = 0;
if (pitchCommand >= fixedwingpathfollowerSettings.PitchLimit.Max && // pitch demand is full up
velocityState.Down > 0 && // we ARE going down
descentspeedDesired < 0 && // we WANT to go up
airspeedError < 0 && // we are too fast already
fixedwingpathfollowerSettings.Safetymargins.Pitchcontrol > 0.5f) { // alarm switched on
fixedwingpathfollowerStatus.Errors.Pitchcontrol = 1;
result = 0;
}
/**
* Calculate where we are heading and why (wind issues)
*/
bearing = attitudeState.Yaw;
heading = RAD2DEG(atan2f(velocityState.East, velocityState.North));
headingError = heading - bearing;
if (headingError < -180.0f) {
headingError += 360.0f;
}
if (headingError > 180.0f) {
headingError -= 360.0f;
}
// Error condition: wind speed is higher than airspeed. We are forced backwards!
fixedwingpathfollowerStatus.Errors.Wind = 0;
if ((headingError > fixedwingpathfollowerSettings.Safetymargins.Wind ||
headingError < -fixedwingpathfollowerSettings.Safetymargins.Wind) &&
fixedwingpathfollowerSettings.Safetymargins.Highpower > 0.5f) { // alarm switched on
// we are flying backwards
fixedwingpathfollowerStatus.Errors.Wind = 1;
result = 0;
}
/**
* Compute desired roll command
*/
if (groundspeedDesired > 1e-6f) {
course = RAD2DEG(atan2f(velocityDesired.East, velocityDesired.North));
courseError = course - heading;
} else {
// if we are not supposed to move, run in a circle
courseError = -90.0f;
result = 0;
}
if (courseError < -180.0f) {
courseError += 360.0f;
}
if (courseError > 180.0f) {
courseError -= 360.0f;
}
courseIntegral = bound(courseIntegral + courseError * dT * fixedwingpathfollowerSettings.CoursePI.Ki,
-fixedwingpathfollowerSettings.CoursePI.ILimit,
fixedwingpathfollowerSettings.CoursePI.ILimit);
courseCommand = (courseError * fixedwingpathfollowerSettings.CoursePI.Kp +
courseIntegral);
fixedwingpathfollowerStatus.Error.Course = courseError;
fixedwingpathfollowerStatus.ErrorInt.Course = courseIntegral;
fixedwingpathfollowerStatus.Command.Course = courseCommand;
stabDesired.Roll = bound(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;
stabDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_NONE;
StabilizationDesiredSet(&stabDesired);
FixedWingPathFollowerStatusSet(&fixedwingpathfollowerStatus);
return result;
}
/**
* Bound input value between limits
*/
static float bound(float val, float min, float max)
{
if (val < min) {
val = min;
} else if (val > max) {
val = max;
}
return val;
}
static void SettingsUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
FixedWingPathFollowerSettingsGet(&fixedwingpathfollowerSettings);
PathDesiredGet(&pathDesired);
}
static void airspeedStateUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
AirspeedStateData airspeedState;
VelocityStateData velocityState;
AirspeedStateGet(&airspeedState);
VelocityStateGet(&velocityState);
float groundspeed = sqrtf(velocityState.East * velocityState.East + velocityState.North * velocityState.North);
indicatedAirspeedStateBias = airspeedState.CalibratedAirspeed - groundspeed;
// 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.
}
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