+++ /dev/null
-// autobrake.cxx - generic, configurable autobrake system
-//
-// Written by James Turner, started September 2009.
-//
-// Copyright (C) 2009 Curtis L. Olson
-//
-// 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 2 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-//
-// $Id$
-
-#include "autobrake.hxx"
-
-#include <Main/fg_props.hxx>
-
-FGAutoBrake::FGAutoBrake() :
- _lastGroundspeedKts(0.0),
- _step(0),
- _rto(false),
- _armed(false),
- _rtoArmed(false),
- _engaged(false),
- _targetDecel(0.0),
- _fcsBrakeControl(0.0),
- _leftBrakeOutput(0.0),
- _rightBrakeOutput(0.0)
-{
- // default config, close to Boeing 747-400 / 777 values
- _configNumSteps = 4;
- _configRTOStep = -1;
- _configDisengageStep = 0;
- _configMaxDecel = 11; // ft-sec-sec
- _configRTODecel = 11; // ft-sec-sec
- _configRTOSpeed = 85; // kts
-}
-
-FGAutoBrake::~FGAutoBrake()
-{
-}
-
-void FGAutoBrake::init()
-{
- _root = fgGetNode("/autopilot/autobrake", true);
-
- _root->tie("armed", SGRawValueMethods<FGAutoBrake, bool>
- (*this, &FGAutoBrake::getArmed, &FGAutoBrake::setArmed));
-
- _root->tie("step", SGRawValueMethods<FGAutoBrake, int>
- (*this, &FGAutoBrake::getStep, &FGAutoBrake::setStep));
-
- _root->tie("rto", SGRawValueMethods<FGAutoBrake, bool>
- (*this, &FGAutoBrake::getRTO, &FGAutoBrake::setRTO));
-
- _engineControlsNode = fgGetNode("/controls/engines");
-
- // brake position nodes
- _brakeInputs[0] = fgGetNode("/controls/gear/brake-left");
- _brakeInputs[1] = fgGetNode("/controls/gear/brake-right");
- _brakeInputs[2] = fgGetNode("/controls/gear/copilot-brake-left");
- _brakeInputs[3] = fgGetNode("/controls/gear/copilot-brake-right");
-
- // config
- SGPropertyNode_ptr config = _root->getChild("config", 0, true);
- config->tie("num-steps", SGRawValuePointer<int>(&_configNumSteps));
- config->tie("rto-step", SGRawValuePointer<int>(&_configRTOStep));
- config->tie("disengage-step", SGRawValuePointer<int>(&_configDisengageStep));
- config->tie("rto-decel-fts-sec", SGRawValuePointer<double>(&_configRTODecel));
- config->tie("max-decel-fts-sec", SGRawValuePointer<double>(&_configMaxDecel));
- config->tie("rto-engage-kts", SGRawValuePointer<double>(&_configRTOSpeed));
-
-
- // outputs
- _root->tie("target-decel-fts-sec",
- SGRawValueMethods<FGAutoBrake,double>(*this, &FGAutoBrake::getTargetDecel));
- _root->tie("actual-decel-fts-sec",
- SGRawValueMethods<FGAutoBrake,double>(*this, &FGAutoBrake::getActualDecel));
- _root->tie("fcs-brake", SGRawValuePointer<double>(&_fcsBrakeControl));
- _root->tie("brake-left-output", SGRawValuePointer<double>(&_leftBrakeOutput));
- _root->tie("brake-right-output", SGRawValuePointer<double>(&_rightBrakeOutput));
-
- _root->tie("engaged", SGRawValueMethods<FGAutoBrake, bool>(*this, &FGAutoBrake::getEngaged));
-}
-
-void FGAutoBrake::postinit()
-{
- _weightOnWheelsNode = fgGetNode("/gear/gear/wow");
- _groundspeedNode = fgGetNode("/velocities/groundspeed-kt");
- if (!_weightOnWheelsNode) {
- return; // don't crash if we're using an acft (UFO, ATC, with no WoW flag)
- }
-
- _lastWoW = _weightOnWheelsNode->getBoolValue();
-}
-
-
-void FGAutoBrake::bind()
-{
-}
-
-void FGAutoBrake::unbind()
-{
-}
-
-void FGAutoBrake::update(double dt)
-{
- _leftBrakeInput = SGMiscd::max(_brakeInputs[0]->getDoubleValue(),
- _brakeInputs[2]->getDoubleValue());
- _rightBrakeInput = SGMiscd::max(_brakeInputs[1]->getDoubleValue(),
- _brakeInputs[3]->getDoubleValue());
-
- // various FDMs don't supply sufficent information for us to work,
- // so just be passive in those cases.
- if (!_weightOnWheelsNode || !_groundspeedNode || !_engineControlsNode) {
- // pass the values straight through
- _leftBrakeOutput = _leftBrakeInput;
- _rightBrakeOutput = _rightBrakeInput;
- return;
- }
-
- if (dt <= 0.0) {
- return; // paused
- }
-
- double gs = _groundspeedNode->getDoubleValue();
- _actualDecel = (_lastGroundspeedKts - gs) / dt;
- _lastGroundspeedKts = gs;
-
- if (!_armed || (_step == 0)) {
- // even if we're off or disarmed, the physical valve system must pass
- // pilot control values through.
- _leftBrakeOutput = _leftBrakeInput;
- _rightBrakeOutput = _rightBrakeInput;
- return;
- }
-
- if (_engaged) {
- updateEngaged(dt);
- } else {
- bool e = shouldEngage();
- if (e) {
- engage();
- updateEngaged(dt);
- }
- }
-
- // sum pilot inpiuts with auto-brake FCS input
- _leftBrakeOutput = SGMiscd::max(_leftBrakeInput, _fcsBrakeControl);
- _rightBrakeOutput = SGMiscd::max(_rightBrakeInput, _fcsBrakeControl);
-
- _lastWoW = _weightOnWheelsNode->getBoolValue();
-}
-
-void FGAutoBrake::engage()
-{
- SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: engaging");
- _engaged = true;
-}
-
-void FGAutoBrake::updateEngaged(double dt)
-{
- // check for pilot braking input cancelling engage
- const double BRAKE_INPUT_THRESHOLD = 0.02; // 2% application triggers
- if ((_leftBrakeInput > BRAKE_INPUT_THRESHOLD) || (_rightBrakeInput > BRAKE_INPUT_THRESHOLD)) {
- SG_LOG(SG_AUTOPILOT, SG_INFO, "auto-brake, detected pilot brake input, disengaing");
- disengage();
- return;
- }
-
- if (!throttlesAtIdle()) {
- SG_LOG(SG_AUTOPILOT, SG_INFO, "auto-brake, throttles not at idle, disengaing");
- disengage();
- return;
- }
-
- // update the target deceleration; note step can be changed while engaged
- if (_rto) {
- _targetDecel = _configRTODecel;
- } else {
- double f = (double) _step / _configNumSteps;
- _targetDecel = _configMaxDecel * f;
- }
-}
-
-bool FGAutoBrake::shouldEngage()
-{
- if (_rto) {
- return shouldEngageRTO();
- }
-
- if (_lastWoW || !_weightOnWheelsNode->getBoolValue()) {
- return false;
- }
-
-
- if (!throttlesAtIdle()) {
- return false;
- }
-
- SG_LOG(SG_AUTOPILOT, SG_INFO, "Autobrake, should enage");
- return true;
-}
-
-bool FGAutoBrake::shouldEngageRTO()
-{
- double speed = _groundspeedNode->getDoubleValue();
-
- if (_rtoArmed) {
- if (speed < _configRTOSpeed) {
- SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: RTO armed, but speed is now below arming speed");
- _rtoArmed = false;
- return false;
- }
-
- if (!_weightOnWheelsNode->getBoolValue()) {
- if (airborne()) {
- SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: RTO, airbone, disengaging");
- _rtoArmed = false;
- _armed = false;
- _step = _configDisengageStep;
- }
-
- return false;
- }
-
- if (throttlesAtIdle()) {
- SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: RTO, throttles at idle, will engage");
- return true;
- } else {
- return false;
- }
- } else {
- // RTO arming case
- if (speed > _configRTOSpeed) {
- SG_LOG(SG_AUTOPILOT, SG_INFO, "Autobrake RTO: passed " << _configRTOSpeed << " knots, arming RTO mode");
- _rtoArmed = true;
- }
- }
-
- return false;
-}
-
-void FGAutoBrake::disengage()
-{
- if (!_engaged) {
- return;
- }
-
- SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: disengage");
- _engaged = false;
- _fcsBrakeControl = 0.0;
- _armed = false;
- _rtoArmed = false;
- _targetDecel = 0.0;
- _step = _configDisengageStep;
-}
-
-bool FGAutoBrake::airborne() const
-{
- return !_weightOnWheelsNode->getBoolValue();
-}
-
-bool FGAutoBrake::throttlesAtIdle() const
-{
- SGPropertyNode_ptr e;
- const double IDLE_THROTTLE = 0.05; // 5% margin for idle setting
-
- for (int index=0; (e = _engineControlsNode->getChild("engine", index)) != NULL; ++index) {
- if ((e->getDoubleValue("throttle") > IDLE_THROTTLE) && !e->getBoolValue("reverser")) {
- return false;
- }
- } // of engines iteration
-
- return true;
-}
-
-void FGAutoBrake::setArmed(bool aArmed)
-{
- if (aArmed == _armed) {
- return;
- }
-
- disengage();
- _armed = aArmed;
-}
-
-void FGAutoBrake::setRTO(bool aRTO)
-{
- if (aRTO) {
- // ensure we meet RTO selection criteria:
- if (!_weightOnWheelsNode->getBoolValue()) {
- // some systems combine RTO with a standard step, selecting RTO if on
- // the ground. Handle that case by setting _rto = false, and letting
- // setStep() do the rest of the work as normal.
- if ((_configRTOStep > 0) && (_configRTOStep <= _configNumSteps)) {
- // RTO is combined with a normal step, select that
- } else {
- SG_LOG(SG_AUTOPILOT, SG_WARN, "auto-brake: cannot select RTO mode, no weight on wheels");
- }
-
- _rto = false;
- return;
- }
-
- _rtoArmed = false;
- _rto = true;
- _step = _configRTOStep;
- setArmed(true);
- SG_LOG(SG_AUTOPILOT, SG_INFO, "RTO mode set");
- } else {
- _rto = false;
- _rtoArmed = false;
- // and if we're enaged?
- disengage();
- }
-}
-
-void FGAutoBrake::setStep(int aStep)
-{
- if (aStep == _step) {
- return;
- }
-
- SG_LOG(SG_AUTOPILOT, SG_INFO, "Autobrake step now=" << aStep);
- _step = aStep;
- bool validStep = false;
-
- if (aStep == _configRTOStep) {
- setRTO(true);
- validStep = true;
- } else {
- _rto = false;
- validStep = (_step > 0) && (_step <= _configNumSteps);
- }
-
- setArmed(validStep); // selecting a valid step arms the system
-}
-
-
+++ /dev/null
-// autobrake.hxx - generic, configurable autobrake system
-//
-// Written by James Turner, started September 2009.
-//
-// Copyright (C) 2009 Curtis L. Olson
-//
-// 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 2 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-//
-// $Id$
-
-#ifndef FG_INSTR_AUTOBRAKE_HXX
-#define FG_INSTR_AUTOBRAKE_HXX
-
-#include <simgear/props/props.hxx>
-#include <simgear/structure/subsystem_mgr.hxx>
-
-// forward decls
-
-class FGAutoBrake : public SGSubsystem
-{
-public:
- FGAutoBrake();
- virtual ~FGAutoBrake();
-
- virtual void init ();
- virtual void postinit ();
- virtual void bind ();
- virtual void unbind ();
- virtual void update (double dt);
-
-private:
-
- void engage();
- void disengage();
-
- void updateEngaged(double dt);
-
- bool shouldEngage();
- bool shouldEngageRTO();
-
- /**
- * Helper to determine if all throttles are at idle
- * (or have reverse thrust engaged)
- */
- bool throttlesAtIdle() const;
-
- /**
- * Helper to determine if we're airbone, i.e weight off all wheels
- */
- bool airborne() const;
-
-// accessors, mostly for SGRawValueMethods use
- void setArmed(bool aArmed);
- bool getArmed() const { return _armed; }
-
- void setRTO(bool aRTO);
- bool getRTO() const { return _rto; }
-
- void setStep(int aStep);
- int getStep() const { return _step; }
-
- bool getEngaged() const { return _engaged;}
- double getTargetDecel() const { return _targetDecel; }
- double getActualDecel() const { return _actualDecel; }
-
-// members
- double _lastGroundspeedKts;
- int _step;
- bool _rto; // true if in Rejected TakeOff mode
- bool _armed;
- bool _rtoArmed; ///< true if we have met arming criteria for RTO mode
- bool _engaged; ///< true if auto-braking is currently active
- double _targetDecel; // target deceleration ft-sec^2
- double _actualDecel; // measured current deceleration in ft-sec^2
- double _fcsBrakeControl;
- bool _lastWoW;
- double _leftBrakeInput; // summed pilot and co-pilot left brake input
- double _rightBrakeInput; // summed pilot and co-pilot right brake input
- double _leftBrakeOutput;
- double _rightBrakeOutput;
-
- SGPropertyNode_ptr _root;
- SGPropertyNode_ptr _brakeInputs[4];
- SGPropertyNode_ptr _weightOnWheelsNode;
- SGPropertyNode_ptr _engineControlsNode;
- SGPropertyNode_ptr _groundspeedNode;
-
- int _configNumSteps;
- int _configRTOStep;
- int _configDisengageStep;
- double _configMaxDecel; ///< deceleration (in ft-sec^2) corresponding to step=numSteps
- double _configRTODecel; ///< deceleration (in ft-sec^2) to use in RTO mode
- double _configRTOSpeed; ///< speed (in kts) for RTO mode to arm
-};
-
-#endif // of FG_INSTR_AUTOBRAKE_HXX
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