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LibrePilot/flight/modules/AltitudeHold/altitudehold.c

317 lines
12 KiB
C

/**
******************************************************************************
*
* @file guidance.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 <math.h>
#include <CoordinateConversions.h>
#include <altholdsmoothed.h>
#include <attitudestate.h>
#include <altitudeholdsettings.h>
#include <altitudeholddesired.h> // object that will be updated by the module
#include <barosensor.h>
#include <positionstate.h>
#include <flightstatus.h>
#include <stabilizationdesired.h>
#include <accelstate.h>
#include <taskinfo.h>
#include <pios_constants.h>
#include <velocitystate.h>
#include <positionstate.h>
// Private constants
#define MAX_QUEUE_SIZE 2
#define STACK_SIZE_BYTES 1024
#define TASK_PRIORITY (tskIDLE_PRIORITY + 1)
#define ACCEL_DOWNSAMPLE 4
#define TIMEOUT_TRESHOLD 200000
#define DESIRED_UPDATE_RATE_MS 100 // milliseconds
// Private types
// Private variables
static xTaskHandle altitudeHoldTaskHandle;
static xQueueHandle queue;
static AltitudeHoldSettingsData altitudeHoldSettings;
static float throttleAlpha = 1.0f;
static float throttle_old = 0.0f;
// Private functions
static void altitudeHoldTask(void *parameters);
static void SettingsUpdatedCb(UAVObjEvent *ev);
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t AltitudeHoldStart()
{
// Start main task
xTaskCreate(altitudeHoldTask, (signed char *)"AltitudeHold", STACK_SIZE_BYTES / 4, NULL, TASK_PRIORITY, &altitudeHoldTaskHandle);
PIOS_TASK_MONITOR_RegisterTask(TASKINFO_RUNNING_ALTITUDEHOLD, altitudeHoldTaskHandle);
return 0;
}
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t AltitudeHoldInitialize()
{
AltitudeHoldSettingsInitialize();
AltitudeHoldDesiredInitialize();
AltHoldSmoothedInitialize();
// Create object queue
queue = xQueueCreate(MAX_QUEUE_SIZE, sizeof(UAVObjEvent));
AltitudeHoldSettingsConnectCallback(&SettingsUpdatedCb);
return 0;
}
MODULE_INITCALL(AltitudeHoldInitialize, AltitudeHoldStart);
float tau;
float positionAlpha;
float velAlpha;
bool running = false;
float velocity;
float velocityIntegral;
float altitudeIntegral;
float error;
float velError;
float derivative;
uint32_t timeval;
bool posUpdated;
/**
* Module thread, should not return.
*/
static void altitudeHoldTask(__attribute__((unused)) void *parameters)
{
AltitudeHoldDesiredData altitudeHoldDesired;
StabilizationDesiredData stabilizationDesired;
AltHoldSmoothedData altHold;
VelocityStateData velocityData;
float dT;
float fblimit = 0;
portTickType thisTime, lastUpdateTime;
UAVObjEvent ev;
dT = 0;
timeval = 0;
lastUpdateTime = 0;
// Force update of the settings
SettingsUpdatedCb(&ev);
// Failsafe handling
uint32_t lastAltitudeHoldDesiredUpdate = 0;
bool enterFailSafe = false;
// Listen for updates.
AltitudeHoldDesiredConnectQueue(queue);
// PositionStateConnectQueue(queue);
FlightStatusConnectQueue(queue);
VelocityStateConnectQueue(queue);
bool altitudeHoldFlightMode = false;
running = false;
enum init_state { WAITING_BARO, WAITIING_INIT, INITED } init = WAITING_BARO;
uint8_t flightMode;
FlightStatusFlightModeGet(&flightMode);
// initialize enable flag
altitudeHoldFlightMode = flightMode == FLIGHTSTATUS_FLIGHTMODE_ALTITUDEHOLD || flightMode == FLIGHTSTATUS_FLIGHTMODE_ALTITUDEVARIO;
// Main task loop
while (1) {
enterFailSafe = PIOS_DELAY_DiffuS(lastAltitudeHoldDesiredUpdate) > TIMEOUT_TRESHOLD;
// Wait until the AttitudeRaw object is updated, if a timeout then go to failsafe
if (xQueueReceive(queue, &ev, 100 / portTICK_RATE_MS) != pdTRUE) {
if (!running) {
altitudeIntegral = 0;
}
// Todo: Add alarm if it should be running
continue;
} else if (ev.obj == FlightStatusHandle()) {
FlightStatusFlightModeGet(&flightMode);
altitudeHoldFlightMode = flightMode == FLIGHTSTATUS_FLIGHTMODE_ALTITUDEHOLD || flightMode == FLIGHTSTATUS_FLIGHTMODE_ALTITUDEVARIO;
if (altitudeHoldFlightMode && !running) {
AttitudeStateData attitudeState;
float q[4], Rbe[3][3];
AttitudeStateGet(&attitudeState);
q[0] = attitudeState.q1;
q[1] = attitudeState.q2;
q[2] = attitudeState.q3;
q[3] = attitudeState.q4;
Quaternion2R(q, Rbe);
// Copy the current throttle as a starting point for integral
float initThrottle;
StabilizationDesiredThrottleGet(&initThrottle);
initThrottle *= Rbe[2][2]; // rotate into earth frame
if (initThrottle > 1) {
initThrottle = 1;
} else if (initThrottle < 0) {
initThrottle = 0;
}
error = 0;
altitudeHoldDesired.Velocity = 0;
altitudeHoldDesired.Altitude = altHold.Altitude;
altitudeIntegral = initThrottle;
velocityIntegral = 0;
running = true;
} else if (!altitudeHoldFlightMode) {
running = false;
lastAltitudeHoldDesiredUpdate = PIOS_DELAY_GetRaw();
}
} else if (ev.obj == VelocityStateHandle()) {
init = (init == WAITING_BARO) ? WAITIING_INIT : init;
dT = 0.1f * PIOS_DELAY_DiffuS(timeval) / 1.0e6f + 0.9f * dT;
timeval = PIOS_DELAY_GetRaw();
AltHoldSmoothedGet(&altHold);
VelocityStateGet(&velocityData);
altHold.Velocity = -(velAlpha * altHold.Velocity + (1 - velAlpha) * velocityData.Down);
float position;
PositionStateDownGet(&position);
altHold.Altitude = -(positionAlpha * position) + (1 - positionAlpha) * altHold.Altitude;
AltHoldSmoothedSet(&altHold);
// Verify that we are in altitude hold mode
uint8_t armed;
FlightStatusArmedGet(&armed);
if (!altitudeHoldFlightMode || armed != FLIGHTSTATUS_ARMED_ARMED) {
running = false;
}
if (!running) {
lastAltitudeHoldDesiredUpdate = PIOS_DELAY_GetRaw();
continue;
}
float lastError = error;
error = altitudeHoldDesired.Altitude - altHold.Altitude;
derivative = (error - lastError) / dT;
velError = altitudeHoldDesired.Velocity - altHold.Velocity;
// Compute altitude and velocity integral
altitudeIntegral += (error - fblimit) * altitudeHoldSettings.AltitudePID[ALTITUDEHOLDSETTINGS_ALTITUDEPID_KI] * dT;
velocityIntegral += (velError - fblimit) * altitudeHoldSettings.VelocityPI[ALTITUDEHOLDSETTINGS_VELOCITYPI_KI] * dT;
thisTime = xTaskGetTickCount();
// Only update stabilizationDesired less frequently
if ((thisTime - lastUpdateTime) * 1000 / configTICK_RATE_HZ < DESIRED_UPDATE_RATE_MS) {
continue;
}
lastUpdateTime = thisTime;
// Instead of explicit limit on integral you output limit feedback
StabilizationDesiredGet(&stabilizationDesired);
if (!enterFailSafe) {
stabilizationDesired.Throttle = altitudeIntegral + velocityIntegral
+ error * altitudeHoldSettings.AltitudePID[ALTITUDEHOLDSETTINGS_ALTITUDEPID_KP]
+ velError * altitudeHoldSettings.VelocityPI[ALTITUDEHOLDSETTINGS_VELOCITYPI_KP]
+ derivative * altitudeHoldSettings.AltitudePID[ALTITUDEHOLDSETTINGS_ALTITUDEPID_KD];
// scale up throttle to compensate for roll/pitch angle but limit this to 60 deg (cos(60) == 0.5) to prevent excessive scaling
AttitudeStateData attitudeState;
float q[4], Rbe[3][3];
AttitudeStateGet(&attitudeState);
q[0] = attitudeState.q1;
q[1] = attitudeState.q2;
q[2] = attitudeState.q3;
q[3] = attitudeState.q4;
Quaternion2R(q, Rbe);
float throttlescale = Rbe[2][2] < 0.5f ? 0.5f : Rbe[2][2];
stabilizationDesired.Throttle /= throttlescale;
stabilizationDesired.Throttle = stabilizationDesired.Throttle * throttleAlpha + throttle_old * (1.0f - throttleAlpha);
throttle_old = stabilizationDesired.Throttle;
fblimit = 0;
if (stabilizationDesired.Throttle > 1) {
fblimit = stabilizationDesired.Throttle - 1;
stabilizationDesired.Throttle = 1;
} else if (stabilizationDesired.Throttle < 0) {
fblimit = stabilizationDesired.Throttle;
stabilizationDesired.Throttle = 0;
}
} else {
// shutdown motors
stabilizationDesired.Throttle = -1;
}
stabilizationDesired.StabilizationMode.Roll = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabilizationDesired.StabilizationMode.Pitch = STABILIZATIONDESIRED_STABILIZATIONMODE_ATTITUDE;
stabilizationDesired.StabilizationMode.Yaw = STABILIZATIONDESIRED_STABILIZATIONMODE_AXISLOCK;
stabilizationDesired.Roll = altitudeHoldDesired.Roll;
stabilizationDesired.Pitch = altitudeHoldDesired.Pitch;
stabilizationDesired.Yaw = altitudeHoldDesired.Yaw;
StabilizationDesiredSet(&stabilizationDesired);
} else if (ev.obj == AltitudeHoldDesiredHandle()) {
// reset the failsafe timer
lastAltitudeHoldDesiredUpdate = PIOS_DELAY_GetRaw();
AltitudeHoldDesiredGet(&altitudeHoldDesired);
}
}
}
static void SettingsUpdatedCb(__attribute__((unused)) UAVObjEvent *ev)
{
AltitudeHoldSettingsGet(&altitudeHoldSettings);
positionAlpha = expf(-(1000.0f / 666.0f * ACCEL_DOWNSAMPLE) / altitudeHoldSettings.PositionTau);
velAlpha = expf(-(1000.0f / 666.0f * ACCEL_DOWNSAMPLE) / altitudeHoldSettings.VelocityTau);
// don't use throttle filter if specified cutoff frequency is too low or above nyquist criteria (half the sampling frequency)
if (altitudeHoldSettings.ThrottleFilterCutoff > 0.001f && altitudeHoldSettings.ThrottleFilterCutoff < 2000.0f / DESIRED_UPDATE_RATE_MS) {
throttleAlpha = (float)DESIRED_UPDATE_RATE_MS / ((float)DESIRED_UPDATE_RATE_MS + 1000.0f / (2.0f * M_PI_F * altitudeHoldSettings.ThrottleFilterCutoff));
} else {
throttleAlpha = 1.0f;
}
}