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flightgear/src/FDM/JSBSim/models/flight_control/FGSensor.cpp

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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Module: FGSensor.cpp
Author: Jon Berndt
Date started: 9 July 2005
------------- Copyright (C) 2005 -------------
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser 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 Lesser General Public License for more
details.
You should have received a copy of the GNU Lesser 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.
Further information about the GNU Lesser General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------
HISTORY
--------------------------------------------------------------------------------
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
COMMENTS, REFERENCES, and NOTES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGSensor.h"
#include "input_output/FGXMLElement.h"
#include <iostream>
#include <cstdlib>
using namespace std;
namespace JSBSim {
IDENT(IdSrc,"$Id: FGSensor.cpp,v 1.27 2014/01/13 10:46:10 ehofman Exp $");
IDENT(IdHdr,ID_SENSOR);
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS IMPLEMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
FGSensor::FGSensor(FGFCS* fcs, Element* element) : FGFCSComponent(fcs, element)
{
double denom;
// inputs are read from the base class constructor
bits = quantized = divisions = 0;
PreviousInput = PreviousOutput = 0.0;
min = max = bias = gain = noise_variance = lag = drift_rate = drift = span = 0.0;
granularity = 0.0;
noise_type = 0;
fail_low = fail_high = fail_stuck = false;
Element* quantization_element = element->FindElement("quantization");
if ( quantization_element) {
if ( quantization_element->FindElement("bits") ) {
bits = (int)quantization_element->FindElementValueAsNumber("bits");
}
divisions = (1<<bits);
if ( quantization_element->FindElement("min") ) {
min = quantization_element->FindElementValueAsNumber("min");
}
if ( quantization_element->FindElement("max") ) {
max = quantization_element->FindElementValueAsNumber("max");
}
quant_property = quantization_element->GetAttributeValue("name");
span = max - min;
granularity = span/divisions;
}
if ( element->FindElement("bias") ) {
bias = element->FindElementValueAsNumber("bias");
}
if ( element->FindElement("gain") ) {
gain = element->FindElementValueAsNumber("gain");
}
if ( element->FindElement("drift_rate") ) {
drift_rate = element->FindElementValueAsNumber("drift_rate");
}
if ( element->FindElement("lag") ) {
lag = element->FindElementValueAsNumber("lag");
denom = 2.00 + dt*lag;
ca = dt*lag / denom;
cb = (2.00 - dt*lag) / denom;
}
if ( element->FindElement("noise") ) {
noise_variance = element->FindElementValueAsNumber("noise");
string variation = element->FindElement("noise")->GetAttributeValue("variation");
if (variation == "PERCENT") {
NoiseType = ePercent;
} else if (variation == "ABSOLUTE") {
NoiseType = eAbsolute;
} else {
NoiseType = ePercent;
cerr << "Unknown noise type in sensor: " << Name << endl;
cerr << " defaulting to PERCENT." << endl;
}
string distribution = element->FindElement("noise")->GetAttributeValue("distribution");
if (distribution == "UNIFORM") {
DistributionType = eUniform;
} else if (distribution == "GAUSSIAN") {
DistributionType = eGaussian;
} else {
DistributionType = eUniform;
cerr << "Unknown random distribution type in sensor: " << Name << endl;
cerr << " defaulting to UNIFORM." << endl;
}
}
FGFCSComponent::bind();
bind();
Debug(0);
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGSensor::~FGSensor()
{
Debug(1);
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::ResetPastStates(void)
{
FGFCSComponent::ResetPastStates();
PreviousOutput = PreviousInput = Output = 0.0;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool FGSensor::Run(void)
{
Input = InputNodes[0]->getDoubleValue() * InputSigns[0];
ProcessSensorSignal();
if (IsOutput) SetOutput();
return true;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::ProcessSensorSignal(void)
{
Output = Input; // perfect sensor
// Degrade signal as specified
if (fail_stuck) {
Output = PreviousOutput;
} else {
if (lag != 0.0) Lag(); // models sensor lag and filter
if (noise_variance != 0.0) Noise(); // models noise
if (drift_rate != 0.0) Drift(); // models drift over time
if (gain != 0.0) Gain(); // models a finite gain
if (bias != 0.0) Bias(); // models a finite bias
if (delay != 0) Delay(); // models system signal transport latencies
if (fail_low) Output = -HUGE_VAL;
if (fail_high) Output = HUGE_VAL;
if (bits != 0) Quantize(); // models quantization degradation
Clip();
}
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::Noise(void)
{
double random_value=0.0;
if (DistributionType == eUniform) {
random_value = 2.0*(((double)rand()/(double)RAND_MAX) - 0.5);
} else {
random_value = GaussianRandomNumber();
}
switch( NoiseType ) {
case ePercent:
Output *= (1.0 + noise_variance*random_value);
break;
case eAbsolute:
Output += noise_variance*random_value;
break;
}
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::Bias(void)
{
Output += bias;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::Gain(void)
{
Output *= gain;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::Drift(void)
{
drift += drift_rate*dt;
Output += drift;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::Quantize(void)
{
if (Output < min) Output = min;
if (Output > max) Output = max;
double portion = Output - min;
quantized = (int)(portion/granularity);
Output = quantized*granularity + min;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::Lag(void)
{
// "Output" on the right side of the "=" is the current input
Output = ca * (Output + PreviousInput) + PreviousOutput * cb;
PreviousOutput = Output;
PreviousInput = Input;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGSensor::bind(void)
{
string tmp = Name;
if (Name.find("/") == string::npos) {
tmp = "fcs/" + PropertyManager->mkPropertyName(Name, true);
}
const string tmp_low = tmp + "/malfunction/fail_low";
const string tmp_high = tmp + "/malfunction/fail_high";
const string tmp_stuck = tmp + "/malfunction/fail_stuck";
PropertyManager->Tie( tmp_low, this, &FGSensor::GetFailLow, &FGSensor::SetFailLow);
PropertyManager->Tie( tmp_high, this, &FGSensor::GetFailHigh, &FGSensor::SetFailHigh);
PropertyManager->Tie( tmp_stuck, this, &FGSensor::GetFailStuck, &FGSensor::SetFailStuck);
if (!quant_property.empty()) {
if (quant_property.find("/") == string::npos) { // not found
string qprop = "fcs/" + PropertyManager->mkPropertyName(quant_property, true);
PropertyManager->Tie(qprop, this, &FGSensor::GetQuantized);
}
}
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// The bitmasked value choices are as follows:
// unset: In this case (the default) JSBSim would only print
// out the normally expected messages, essentially echoing
// the config files as they are read. If the environment
// variable is not set, debug_lvl is set to 1 internally
// 0: This requests JSBSim not to output any messages
// whatsoever.
// 1: This value explicity requests the normal JSBSim
// startup messages
// 2: This value asks for a message to be printed out when
// a class is instantiated
// 4: When this value is set, a message is displayed when a
// FGModel object executes its Run() method
// 8: When this value is set, various runtime state variables
// are printed out periodically
// 16: When set various parameters are sanity checked and
// a message is printed out when they go out of bounds
void FGSensor::Debug(int from)
{
if (debug_lvl <= 0) return;
if (debug_lvl & 1) { // Standard console startup message output
if (from == 0) { // Constructor
if (InputSigns.size() > 0) {
if (InputSigns[0] < 0)
cout << " INPUT: -" << InputNodes[0]->GetName() << endl;
else
cout << " INPUT: " << InputNodes[0]->GetName() << endl;
}
if (bits != 0) {
if (quant_property.empty())
cout << " Quantized output" << endl;
else
cout << " Quantized output (property: " << quant_property << ")" << endl;
cout << " Bits: " << bits << endl;
cout << " Min value: " << min << endl;
cout << " Max value: " << max << endl;
cout << " (span: " << span << ", granularity: " << granularity << ")" << endl;
}
if (bias != 0.0) cout << " Bias: " << bias << endl;
if (gain != 0.0) cout << " Gain: " << gain << endl;
if (drift_rate != 0) cout << " Sensor drift rate: " << drift_rate << endl;
if (lag != 0) cout << " Sensor lag: " << lag << endl;
if (noise_variance != 0) {
if (NoiseType == eAbsolute) {
cout << " Noise variance (absolute): " << noise_variance << endl;
} else if (NoiseType == ePercent) {
cout << " Noise variance (percent): " << noise_variance << endl;
} else {
cout << " Noise variance type is invalid" << endl;
}
if (DistributionType == eUniform) {
cout << " Random noise is uniformly distributed." << endl;
} else if (DistributionType == eGaussian) {
cout << " Random noise is gaussian distributed." << endl;
}
}
if (IsOutput) {
for (unsigned int i=0; i<OutputNodes.size(); i++)
cout << " OUTPUT: " << OutputNodes[i]->getName() << endl;
}
}
}
if (debug_lvl & 2 ) { // Instantiation/Destruction notification
if (from == 0) cout << "Instantiated: FGSensor" << endl;
if (from == 1) cout << "Destroyed: FGSensor" << endl;
}
if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
}
if (debug_lvl & 8 ) { // Runtime state variables
}
if (debug_lvl & 16) { // Sanity checking
}
if (debug_lvl & 64) {
if (from == 0) { // Constructor
cout << IdSrc << endl;
cout << IdHdr << endl;
}
}
}
}
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