A generic, configurable autobrake system. Not fully features yet, but works quite nicely in the 777, including RTO modes and auto-disengage on pilot input.
This commit is contained in:
jmt
Tim Moore
parent
6db8687a75
commit
4d67c69462
4 changed files with 403 additions and 2 deletions
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@ -2,6 +2,7 @@ noinst_LIBRARIES = libAutopilot.a
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libAutopilot_a_SOURCES = \
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route_mgr.cxx route_mgr.hxx \
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xmlauto.cxx xmlauto.hxx
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xmlauto.cxx xmlauto.hxx \
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autobrake.cxx autobrake.hxx
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INCLUDES = -I$(top_srcdir) -I$(top_srcdir)/src
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295
src/Autopilot/autobrake.cxx
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295
src/Autopilot/autobrake.cxx
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@ -0,0 +1,295 @@
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// autobrake.cxx - generic, configurable autobrake system
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//
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// Written by James Turner, started September 2009.
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//
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// Copyright (C) 2009 Curtis L. Olson
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// $Id$
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#include "autobrake.hxx"
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#include <Main/fg_props.hxx>
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FGAutoBrake::FGAutoBrake() :
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_lastGroundspeedKts(0.0),
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_step(0),
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_rto(false),
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_armed(false),
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_rtoArmed(false),
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_engaged(false),
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_targetDecel(0.0),
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_fcsBrakeControl(0.0),
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_leftBrakeOutput(0.0),
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_rightBrakeOutput(0.0)
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{
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// default config, close to Boeing 747-400 / 777 values
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_configNumSteps = 4;
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_configRTOStep = -1;
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_configMaxDecel = 11; // ft-sec-sec
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_configRTODecel = 11; // ft-sec-sec
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_configRTOSpeed = 85; // kts
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}
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FGAutoBrake::~FGAutoBrake()
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{
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}
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void FGAutoBrake::init()
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{
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_root = fgGetNode("/autopilot/autobrake", true);
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_root->tie("armed", SGRawValueMethods<FGAutoBrake, bool>
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(*this, &FGAutoBrake::getArmed, &FGAutoBrake::setArmed));
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_root->tie("step", SGRawValueMethods<FGAutoBrake, int>
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(*this, &FGAutoBrake::getStep, &FGAutoBrake::setStep));
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_root->tie("rto", SGRawValueMethods<FGAutoBrake, bool>
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(*this, &FGAutoBrake::getRTO, &FGAutoBrake::setRTO));
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_engineControlsNode = fgGetNode("/controls/engines");
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_groundspeedNode = fgGetNode("/velocities/groundspeed-kt");
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// brake position nodes
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_brakeInputs[0] = fgGetNode("/controls/gear/brake-left");
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_brakeInputs[1] = fgGetNode("/controls/gear/brake-right");
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_brakeInputs[2] = fgGetNode("/controls/gear/copilot-brake-left");
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_brakeInputs[3] = fgGetNode("/controls/gear/copilot-brake-right");
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// config
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SGPropertyNode_ptr config = _root->getChild("config", 0, true);
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config->tie("num-steps", SGRawValuePointer<int>(&_configNumSteps));
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config->tie("rto-step", SGRawValuePointer<int>(&_configRTOStep));
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config->tie("rto-decel-fts-sec", SGRawValuePointer<double>(&_configRTODecel));
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config->tie("max-decel-fts-sec", SGRawValuePointer<double>(&_configMaxDecel));
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config->tie("rto-engage-kts", SGRawValuePointer<double>(&_configRTOSpeed));
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// outputs
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_root->tie("target-decel-fts-sec",
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SGRawValueMethods<FGAutoBrake,double>(*this, &FGAutoBrake::getTargetDecel));
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_root->tie("actual-decel-fts-sec",
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SGRawValueMethods<FGAutoBrake,double>(*this, &FGAutoBrake::getActualDecel));
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_root->tie("fcs-brake", SGRawValuePointer<double>(&_fcsBrakeControl));
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_root->tie("brake-left-output", SGRawValuePointer<double>(&_leftBrakeOutput));
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_root->tie("brake-right-output", SGRawValuePointer<double>(&_rightBrakeOutput));
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_root->tie("engaged", SGRawValueMethods<FGAutoBrake, bool>(*this, &FGAutoBrake::getEngaged));
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}
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void FGAutoBrake::postinit()
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{
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_weightOnWheelsNode = fgGetNode("/gear/gear/wow");
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_lastWoW = _weightOnWheelsNode->getBoolValue();
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}
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void FGAutoBrake::bind()
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{
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}
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void FGAutoBrake::unbind()
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{
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}
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void FGAutoBrake::update(double dt)
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{
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if (dt <= 0.0) {
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return; // paused
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}
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double gs = _groundspeedNode->getDoubleValue();
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_actualDecel = (_lastGroundspeedKts - gs) / dt;
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_lastGroundspeedKts = gs;
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_leftBrakeInput = SGMiscd::max(_brakeInputs[0]->getDoubleValue(),
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_brakeInputs[2]->getDoubleValue());
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_rightBrakeInput = SGMiscd::max(_brakeInputs[1]->getDoubleValue(),
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_brakeInputs[3]->getDoubleValue());
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if (!_armed || (_step == 0)) {
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// even if we're off or disarmed, the physical valve system must pass
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// pilot control values through.
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_leftBrakeOutput = _leftBrakeInput;
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_rightBrakeOutput = _rightBrakeInput;
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return;
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}
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if (_engaged) {
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updateEngaged(dt);
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} else {
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bool e = shouldEngage();
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if (e) {
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engage();
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updateEngaged(dt);
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}
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}
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// sum pilot inpiuts with auto-brake FCS input
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_leftBrakeOutput = SGMiscd::max(_leftBrakeInput, _fcsBrakeControl);
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_rightBrakeOutput = SGMiscd::max(_rightBrakeInput, _fcsBrakeControl);
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_lastWoW = _weightOnWheelsNode->getBoolValue();
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}
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void FGAutoBrake::engage()
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{
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SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: engaging");
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_engaged = true;
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}
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void FGAutoBrake::updateEngaged(double dt)
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{
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// check for pilot braking input cancelling engage
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const double BRAKE_INPUT_THRESHOLD = 0.02; // 2% application triggers
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if ((_leftBrakeInput > BRAKE_INPUT_THRESHOLD) || (_rightBrakeInput > BRAKE_INPUT_THRESHOLD)) {
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SG_LOG(SG_AUTOPILOT, SG_INFO, "auto-brake, detected pilot brake input, disengaing");
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disengage();
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return;
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}
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// update the target deceleration; note step can be changed while engaged
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if (_rto) {
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_targetDecel = _configRTODecel;
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} else {
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double f = (double) _step / _configNumSteps;
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_targetDecel = _configMaxDecel * f;
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}
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}
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bool FGAutoBrake::shouldEngage()
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{
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if (_rto) {
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return shouldEngageRTO();
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}
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if (_lastWoW || !_weightOnWheelsNode->getBoolValue()) {
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return false;
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}
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SG_LOG(SG_AUTOPILOT, SG_INFO, "Autobrake, should enage");
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return true;
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}
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bool FGAutoBrake::shouldEngageRTO()
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{
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double speed = _groundspeedNode->getDoubleValue();
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if (_rtoArmed) {
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if (speed < _configRTOSpeed) {
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SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: RTO armed, but speed is now below arming speed");
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_rtoArmed = false;
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return false;
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}
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if (!_weightOnWheelsNode->getBoolValue()) {
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return false;
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}
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return throttlesAtIdle();
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} else {
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// RTO arming case
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if (speed > _configRTOSpeed) {
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SG_LOG(SG_AUTOPILOT, SG_INFO, "Autobrake RTO: passed " << _configRTOSpeed << " knots, arming RTO mode");
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_rtoArmed = true;
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}
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}
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return false;
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}
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void FGAutoBrake::disengage()
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{
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if (!_engaged) {
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return;
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}
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SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: disengage");
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_engaged = false;
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_armed = false;
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_rtoArmed = false;
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_targetDecel = 0.0;
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}
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bool FGAutoBrake::throttlesAtIdle()
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{
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SGPropertyNode_ptr e;
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const double IDLE_THROTTLE = 0.05; // 5% margin for idle setting
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for (int index=0; (e = _engineControlsNode->getChild("engine", index)) != NULL; ++index) {
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if ((e->getDoubleValue("throttle") > IDLE_THROTTLE) && !e->getBoolValue("reverser")) {
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return false;
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}
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} // of engines iteration
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SG_LOG(SG_AUTOPILOT, SG_INFO, "FGAutoBrake: throttles at idle");
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return true;
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}
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void FGAutoBrake::setArmed(bool aArmed)
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{
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if (aArmed == _armed) {
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return;
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}
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disengage();
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_armed = aArmed;
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}
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void FGAutoBrake::setRTO(bool aRTO)
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{
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if (aRTO) {
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// ensure we meet RTO selection criteria:
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if (!_weightOnWheelsNode->getBoolValue()) {
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SG_LOG(SG_AUTOPILOT, SG_WARN, "auto-brake: cannot select RTO mode, no weight on wheels");
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return;
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}
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_rtoArmed = false;
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_rto = true;
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_step = _configRTOStep;
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setArmed(true);
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SG_LOG(SG_AUTOPILOT, SG_INFO, "RTO mode set");
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} else {
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_rto = false;
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_rtoArmed = false;
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// and if we're enaged?
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disengage();
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}
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}
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void FGAutoBrake::setStep(int aStep)
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{
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if (aStep == _step) {
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return;
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}
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SG_LOG(SG_AUTOPILOT, SG_INFO, "Autobrake step now=" << aStep);
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_step = aStep;
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bool validStep = false;
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if (aStep == _configRTOStep) {
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setRTO(true);
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validStep = true;
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} else {
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_rto = false;
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validStep = (_step > 0) && (_step <= _configNumSteps);
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}
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setArmed(validStep); // selecting a valid step arms the system
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}
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102
src/Autopilot/autobrake.hxx
Normal file
102
src/Autopilot/autobrake.hxx
Normal file
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@ -0,0 +1,102 @@
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// autobrake.hxx - generic, configurable autobrake system
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//
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// Written by James Turner, started September 2009.
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//
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// Copyright (C) 2009 Curtis L. Olson
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// $Id$
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#ifndef FG_INSTR_AUTOBRAKE_HXX
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#define FG_INSTR_AUTOBRAKE_HXX
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#include <simgear/props/props.hxx>
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#include <simgear/structure/subsystem_mgr.hxx>
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// forward decls
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class FGAutoBrake : public SGSubsystem
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{
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public:
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FGAutoBrake();
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virtual ~FGAutoBrake();
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virtual void init ();
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virtual void postinit ();
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virtual void bind ();
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virtual void unbind ();
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virtual void update (double dt);
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private:
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void engage();
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void disengage();
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void updateEngaged(double dt);
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bool shouldEngage();
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bool shouldEngageRTO();
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/**
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* Helper to determine if all throttles are at idle
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* (or have reverse thrust engaged)
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*/
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bool throttlesAtIdle();
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// accessors, mostly for SGRawValueMethods use
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void setArmed(bool aArmed);
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bool getArmed() const { return _armed; }
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void setRTO(bool aRTO);
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bool getRTO() const { return _rto; }
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void setStep(int aStep);
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int getStep() const { return _step; }
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bool getEngaged() const { return _engaged;}
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double getTargetDecel() const { return _targetDecel; }
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double getActualDecel() const { return _actualDecel; }
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// members
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double _lastGroundspeedKts;
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int _step;
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bool _rto; // true if in Rejected TakeOff mode
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bool _armed;
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bool _rtoArmed; ///< true if we have met arming criteria for RTO mode
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bool _engaged; ///< true if auto-braking is currently active
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double _targetDecel; // target deceleration ft-sec^2
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double _actualDecel; // measured current deceleration in ft-sec^2
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double _fcsBrakeControl;
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bool _lastWoW;
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double _leftBrakeInput; // summed pilot and co-pilot left brake input
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double _rightBrakeInput; // summed pilot and co-pilot right brake input
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double _leftBrakeOutput;
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double _rightBrakeOutput;
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SGPropertyNode_ptr _root;
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SGPropertyNode* _brakeInputs[4];
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SGPropertyNode_ptr _weightOnWheelsNode;
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SGPropertyNode_ptr _engineControlsNode;
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SGPropertyNode_ptr _groundspeedNode;
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int _configNumSteps;
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int _configRTOStep;
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double _configMaxDecel; ///< deceleration (in ft-sec^2) corresponding to step=numSteps
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double _configRTODecel; ///< deceleration (in ft-sec^2) to use in RTO mode
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double _configRTOSpeed; ///< speed (in kts) for RTO mode to arm
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};
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#endif // of FG_INSTR_AUTOBRAKE_HXX
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@ -73,6 +73,8 @@
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#include <ATCDCL/AIMgr.hxx>
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#include <Autopilot/route_mgr.hxx>
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#include <Autopilot/xmlauto.hxx>
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#include <Autopilot/autobrake.hxx>
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#include <Cockpit/cockpit.hxx>
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#include <Cockpit/panel.hxx>
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#include <Cockpit/panel_io.hxx>
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@ -1530,6 +1532,7 @@ bool fgInitSubsystems() {
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globals->add_subsystem( "xml-autopilot", new FGXMLAutopilot );
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globals->add_subsystem( "route-manager", new FGRouteMgr );
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globals->add_subsystem( "autobrake", new FGAutoBrake );
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////////////////////////////////////////////////////////////////////
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// Initialize the view manager subsystem.
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