1 // predictor.cxx - predict future values
3 // Written by Torsten Dreyer
4 // Based heavily on work created by Curtis Olson, started January 2004.
6 // Copyright (C) 2004 Curtis L. Olson - http://www.flightgear.org/~curt
7 // Copyright (C) 2010 Torsten Dreyer - Torsten (at) t3r (dot) de
9 // This program is free software; you can redistribute it and/or
10 // modify it under the terms of the GNU General Public License as
11 // published by the Free Software Foundation; either version 2 of the
12 // License, or (at your option) any later version.
14 // This program is distributed in the hope that it will be useful, but
15 // WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 // General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
24 #include "predictor.hxx"
26 using namespace FGXMLAutopilot;
28 //------------------------------------------------------------------------------
29 Predictor::Predictor () :
36 //------------------------------------------------------------------------------
37 bool Predictor::configure( SGPropertyNode& cfg_node,
38 const std::string& cfg_name,
39 SGPropertyNode& prop_root )
41 if( cfg_name == "config" ) {
42 Component::configure(prop_root, cfg_node);
46 if (cfg_name == "seconds") {
47 _seconds.push_back( new InputValue(prop_root, cfg_node, 0) );
51 if (cfg_name == "filter-gain") {
52 _filter_gain.push_back( new InputValue(prop_root, cfg_node, 0) );
56 return AnalogComponent::configure(cfg_node, cfg_name, prop_root);
59 //------------------------------------------------------------------------------
60 void Predictor::update( bool firstTime, double dt )
62 double ivalue = _valueInput.get_value();
68 double current = (ivalue - _last_value)/dt; // calculate current error change (per second)
69 _average = dt < 1.0 ? ((1.0 - dt) * _average + current * dt) : current;
71 // calculate output with filter gain adjustment
72 double output = ivalue +
73 (1.0 - _filter_gain.get_value()) * (_average * _seconds.get_value()) +
74 _filter_gain.get_value() * (current * _seconds.get_value());
75 output = clamp( output );
76 set_output_value( output );