/**
* This method checks the current position against the active waypoint
* to determine if it has been reached
*/
static void checkTerminationCondition()
{
PathStatusData pathStatus;
PathStatusGet(&pathStatus);
path_status_updated = false;
if (pathStatus.Status == PATHSTATUS_STATUS_COMPLETED)
advanceWaypoint();
}
/**
* Compute desired velocity from the current position and path
*
* Takes in @ref PositionActual and compares it to @ref PathDesired
* and computes @ref VelocityDesired
*/
static void updatePathVelocity()
{
float dT = guidanceSettings.UpdatePeriod / 1000.0f;
PositionActualData positionActual;
PositionActualGet(&positionActual);
float cur[3] = {positionActual.North, positionActual.East, positionActual.Down};
struct path_status progress;
path_progress(&pathDesired, cur, &progress);
// Update the path status UAVO
PathStatusData pathStatus;
PathStatusGet(&pathStatus);
pathStatus.fractional_progress = progress.fractional_progress;
if (pathStatus.fractional_progress < 1)
pathStatus.Status = PATHSTATUS_STATUS_INPROGRESS;
else
pathStatus.Status = PATHSTATUS_STATUS_COMPLETED;
PathStatusSet(&pathStatus);
float groundspeed = pathDesired.StartingVelocity +
(pathDesired.EndingVelocity - pathDesired.StartingVelocity) * progress.fractional_progress;
if(progress.fractional_progress > 1)
groundspeed = 0;
VelocityDesiredData velocityDesired;
velocityDesired.North = progress.path_direction[0] * groundspeed;
velocityDesired.East = progress.path_direction[1] * groundspeed;
float error_speed = progress.error * guidanceSettings.HorizontalPosPI[VTOLPATHFOLLOWERSETTINGS_HORIZONTALPOSPI_KP];
float correction_velocity[2] = {progress.correction_direction[0] * error_speed,
progress.correction_direction[1] * error_speed};
float total_vel = sqrtf(powf(correction_velocity[0],2) + powf(correction_velocity[1],2));
float scale = 1;
if(total_vel > guidanceSettings.HorizontalVelMax)
scale = guidanceSettings.HorizontalVelMax / total_vel;
// Currently not apply a PID loop for horizontal corrections
velocityDesired.North += progress.correction_direction[0] * error_speed * scale;
velocityDesired.East += progress.correction_direction[1] * error_speed * scale;
// Interpolate desired velocity along the path
float altitudeSetpoint = pathDesired.Start[2] + (pathDesired.End[2] - pathDesired.Start[2]) *
bound_min_max(progress.fractional_progress,0,1);
float downError = altitudeSetpoint - positionActual.Down;
velocityDesired.Down = pid_apply_antiwindup(&vtol_pids[DOWN_POSITION], downError,
-guidanceSettings.VerticalVelMax, guidanceSettings.VerticalVelMax, dT);
VelocityDesiredSet(&velocityDesired);
}
/**
* Compute desired velocity from the current position and path
*
* Takes in @ref PositionActual and compares it to @ref PathDesired
* and computes @ref VelocityDesired
*/
static void updatePathVelocity()
{
PositionActualData positionActual;
PositionActualGet(&positionActual);
float cur[3] = {positionActual.North, positionActual.East, positionActual.Down};
struct path_status progress;
path_progress(&pathDesired, cur, &progress);
// Update the path status UAVO
PathStatusData pathStatus;
PathStatusGet(&pathStatus);
pathStatus.fractional_progress = progress.fractional_progress;
if (pathStatus.fractional_progress < 1)
pathStatus.Status = PATHSTATUS_STATUS_INPROGRESS;
else
pathStatus.Status = PATHSTATUS_STATUS_COMPLETED;
PathStatusSet(&pathStatus);
float groundspeed = pathDesired.StartingVelocity +
(pathDesired.EndingVelocity - pathDesired.StartingVelocity) * progress.fractional_progress;
if(progress.fractional_progress > 1)
groundspeed = 0;
VelocityDesiredData velocityDesired;
velocityDesired.North = progress.path_direction[0] * groundspeed;
velocityDesired.East = progress.path_direction[1] * groundspeed;
float error_speed = progress.error * guidanceSettings.HorizontalPosPI[GROUNDPATHFOLLOWERSETTINGS_HORIZONTALPOSPI_KP];
float correction_velocity[2] = {progress.correction_direction[0] * error_speed,
progress.correction_direction[1] * error_speed};
float total_vel = sqrtf(powf(correction_velocity[0],2) + powf(correction_velocity[1],2));
float scale = 1;
if(total_vel > guidanceSettings.HorizontalVelMax)
scale = guidanceSettings.HorizontalVelMax / total_vel;
// Currently not apply a PID loop for horizontal corrections
velocityDesired.North += progress.correction_direction[0] * error_speed * scale;
velocityDesired.East += progress.correction_direction[1] * error_speed * scale;
// No altitude control on a ground vehicle
velocityDesired.Down = 0;
VelocityDesiredSet(&velocityDesired);
}
void PathStatus_Get(struct ParseState *Parser, struct Value *ReturnValue, struct Value **Param, int NumArgs)
{
if (Param[0]->Val->Pointer == NULL)
return;
PathStatusData data;
PathStatusGet(&data);
// use the same struct like picoc. see below
struct mystruct {
double fractional_progress;
double error;
unsigned char Status;
} *pdata;
pdata = Param[0]->Val->Pointer;
pdata->fractional_progress = data.fractional_progress;
pdata->error = data.error;
pdata->Status = data.Status;
}
/**
* Module thread, should not return.
*/
static void pathfollowerTask(void *parameters)
{
SystemSettingsData systemSettings;
FlightStatusData flightStatus;
uint32_t lastUpdateTime;
AirspeedActualConnectCallback(airspeedActualUpdatedCb);
FixedWingPathFollowerSettingsConnectCallback(SettingsUpdatedCb);
FixedWingAirspeedsConnectCallback(SettingsUpdatedCb);
PathDesiredConnectCallback(SettingsUpdatedCb);
// Force update of all the settings
SettingsUpdatedCb(NULL);
FixedWingPathFollowerSettingsGet(&fixedwingpathfollowerSettings);
path_desired_updated = false;
PathDesiredGet(&pathDesired);
PathDesiredConnectCallback(pathDesiredUpdated);
// Main task loop
lastUpdateTime = PIOS_Thread_Systime();
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_PATHFOLLOWER,SYSTEMALARMS_ALARM_CRITICAL);
PIOS_Thread_Sleep(1000);
continue;
}
// Continue collecting data if not enough time
PIOS_Thread_Sleep_Until(&lastUpdateTime, fixedwingpathfollowerSettings.UpdatePeriod);
static uint8_t last_flight_mode;
FlightStatusGet(&flightStatus);
PathStatusGet(&pathStatus);
PositionActualData positionActual;
static enum {FW_FOLLOWER_IDLE, FW_FOLLOWER_RUNNING, FW_FOLLOWER_ERR} state = FW_FOLLOWER_IDLE;
// Check whether an update to the path desired occured and we should
// process it. This makes sure that the follower alarm state is
// updated.
bool process_path_desired_update =
(last_flight_mode == FLIGHTSTATUS_FLIGHTMODE_PATHPLANNER ||
last_flight_mode == FLIGHTSTATUS_FLIGHTMODE_PATHPLANNER) &&
path_desired_updated;
path_desired_updated = false;
// Process most of these when the flight mode changes
// except when in path following mode in which case
// each iteration must make sure this has the latest
// PathDesired
if (flightStatus.FlightMode != last_flight_mode ||
process_path_desired_update) {
last_flight_mode = flightStatus.FlightMode;
switch(flightStatus.FlightMode) {
case FLIGHTSTATUS_FLIGHTMODE_RETURNTOHOME:
state = FW_FOLLOWER_RUNNING;
PositionActualGet(&positionActual);
pathDesired.Mode = PATHDESIRED_MODE_CIRCLEPOSITIONRIGHT;
pathDesired.Start[0] = positionActual.North;
pathDesired.Start[1] = positionActual.East;
pathDesired.Start[2] = positionActual.Down;
pathDesired.End[0] = 0;
pathDesired.End[1] = 0;
pathDesired.End[2] = -30.0f;
pathDesired.ModeParameters = fixedwingpathfollowerSettings.OrbitRadius;
pathDesired.StartingVelocity = fixedWingAirspeeds.CruiseSpeed;
pathDesired.EndingVelocity = fixedWingAirspeeds.CruiseSpeed;
PathDesiredSet(&pathDesired);
break;
case FLIGHTSTATUS_FLIGHTMODE_POSITIONHOLD:
state = FW_FOLLOWER_RUNNING;
PositionActualGet(&positionActual);
pathDesired.Mode = PATHDESIRED_MODE_CIRCLEPOSITIONRIGHT;
pathDesired.Start[0] = positionActual.North;
pathDesired.Start[1] = positionActual.East;
pathDesired.Start[2] = positionActual.Down;
pathDesired.End[0] = positionActual.North;
pathDesired.End[1] = positionActual.East;
pathDesired.End[2] = positionActual.Down;
pathDesired.ModeParameters = fixedwingpathfollowerSettings.OrbitRadius;
pathDesired.StartingVelocity = fixedWingAirspeeds.CruiseSpeed;
pathDesired.EndingVelocity = fixedWingAirspeeds.CruiseSpeed;
PathDesiredSet(&pathDesired);
break;
case FLIGHTSTATUS_FLIGHTMODE_PATHPLANNER:
case FLIGHTSTATUS_FLIGHTMODE_TABLETCONTROL:
state = FW_FOLLOWER_RUNNING;
PathDesiredGet(&pathDesired);
switch(pathDesired.Mode) {
case PATHDESIRED_MODE_ENDPOINT:
case PATHDESIRED_MODE_VECTOR:
case PATHDESIRED_MODE_CIRCLERIGHT:
case PATHDESIRED_MODE_CIRCLELEFT:
break;
default:
state = FW_FOLLOWER_ERR;
pathStatus.Status = PATHSTATUS_STATUS_CRITICAL;
PathStatusSet(&pathStatus);
AlarmsSet(SYSTEMALARMS_ALARM_PATHFOLLOWER,SYSTEMALARMS_ALARM_CRITICAL);
break;
}
break;
default:
state = FW_FOLLOWER_IDLE;
break;
}
}
switch(state) {
case FW_FOLLOWER_RUNNING:
{
updatePathVelocity();
uint8_t result = updateFixedDesiredAttitude();
if (result) {
AlarmsClear(SYSTEMALARMS_ALARM_PATHFOLLOWER);
} else {
AlarmsSet(SYSTEMALARMS_ALARM_PATHFOLLOWER,SYSTEMALARMS_ALARM_WARNING);
}
PathStatusSet(&pathStatus);
break;
}
case FW_FOLLOWER_IDLE:
// Be cleaner and get rid of global variables
northVelIntegral = 0;
eastVelIntegral = 0;
downVelIntegral = 0;
bearingIntegral = 0;
speedIntegral = 0;
accelIntegral = 0;
powerIntegral = 0;
airspeedErrorInt = 0;
AlarmsClear(SYSTEMALARMS_ALARM_PATHFOLLOWER);
break;
case FW_FOLLOWER_ERR:
default:
// Leave alarms set above
break;
}
}
}
/**
* Compute desired velocity to follow the desired path from the current location.
* @param[in] dT the time since last evaluation
* @param[in] pathDesired the desired path to follow
* @param[out] progress the current progress information along that path
* @returns 0 if successful, <0 if an error occurred
*
* The calculated velocity to attempt is stored in @ref VelocityDesired
*/
int32_t vtol_follower_control_path(const float dT, const PathDesiredData *pathDesired,
struct path_status *progress)
{
PositionActualData positionActual;
PositionActualGet(&positionActual);
VelocityActualData velocityActual;
VelocityActualGet(&velocityActual);
PathStatusData pathStatus;
PathStatusGet(&pathStatus);
const float cur_pos_ned[3] = {
positionActual.North +
velocityActual.North * guidanceSettings.PositionFeedforward,
positionActual.East +
velocityActual.East * guidanceSettings.PositionFeedforward,
positionActual.Down };
path_progress(pathDesired, cur_pos_ned, progress);
// Check if we have already completed this leg
bool current_leg_completed =
(pathStatus.Status == PATHSTATUS_STATUS_COMPLETED) &&
(pathStatus.Waypoint == pathDesired->Waypoint);
pathStatus.fractional_progress = progress->fractional_progress;
pathStatus.error = progress->error;
pathStatus.Waypoint = pathDesired->Waypoint;
// Figure out how low (high) we should be and the error
const float altitudeSetpoint = vtol_interpolate(progress->fractional_progress,
pathDesired->Start[2], pathDesired->End[2]);
const float downError = altitudeSetpoint - positionActual.Down;
// If leg is completed signal this
if (current_leg_completed || pathStatus.fractional_progress > 1.0f) {
const bool criterion_altitude =
(downError > -guidanceSettings.WaypointAltitudeTol) ||
(!guidanceSettings.ThrottleControl);
// Once we complete leg and hit altitude criterion signal this
// waypoint is done. Or if we're not controlling throttle,
// ignore height for completion.
// Waypoint heights are thus treated as crossing restrictions-
// cross this point at or above...
if (criterion_altitude || current_leg_completed) {
pathStatus.Status = PATHSTATUS_STATUS_COMPLETED;
PathStatusSet(&pathStatus);
} else {
pathStatus.Status = PATHSTATUS_STATUS_INPROGRESS;
PathStatusSet(&pathStatus);
}
// Wait here for new path segment
return vtol_follower_control_simple(dT, pathDesired->End, false, false);
}
// Interpolate desired velocity and altitude along the path
float groundspeed = vtol_interpolate(progress->fractional_progress,
pathDesired->StartingVelocity, pathDesired->EndingVelocity);
float error_speed = vtol_deadband(progress->error,
guidanceSettings.PathDeadbandWidth,
guidanceSettings.PathDeadbandCenterGain,
vtol_path_m, vtol_path_r) *
guidanceSettings.HorizontalPosPI[VTOLPATHFOLLOWERSETTINGS_HORIZONTALPOSPI_KP];
/* Sum the desired path movement vector with the correction vector */
float commands_ned[3];
commands_ned[0] = progress->path_direction[0] * groundspeed +
progress->correction_direction[0] * error_speed;
commands_ned[1] = progress->path_direction[1] * groundspeed +
progress->correction_direction[1] * error_speed;
/* Limit the total velocity based on the configured value. */
vtol_limit_velocity(commands_ned, guidanceSettings.HorizontalVelMax);
commands_ned[2] = pid_apply_antiwindup(&vtol_pids[DOWN_POSITION], downError,
-guidanceSettings.VerticalVelMax, guidanceSettings.VerticalVelMax, dT);
VelocityDesiredData velocityDesired;
VelocityDesiredGet(&velocityDesired);
velocityDesired.North = commands_ned[0];
velocityDesired.East = commands_ned[1];
velocityDesired.Down = commands_ned[2];
VelocityDesiredSet(&velocityDesired);
pathStatus.Status = PATHSTATUS_STATUS_INPROGRESS;
PathStatusSet(&pathStatus);
return 0;
}
