diff --git a/src/Systems/electrical.cxx b/src/Systems/electrical.cxx index db2dce223..31a4e5594 100644 --- a/src/Systems/electrical.cxx +++ b/src/Systems/electrical.cxx @@ -48,16 +48,21 @@ FGElectricalSupplier::FGElectricalSupplier ( SGPropertyNode *node ) { // cout << "_model = " << _model << endl; if ( _model == "battery" ) { model = FG_BATTERY; + amp_hours = node->getFloatValue("amp-hours", 40.0); + percent_remaining = node->getFloatValue("percent-remaining", 1.0); + charge_amps = node->getFloatValue("charge-amps", 7.0); } else if ( _model == "alternator" ) { model = FG_ALTERNATOR; + rpm_src = node->getStringValue("rpm-source"); + rpm_threshold = node->getFloatValue("rpm-threshold", 600.0); + ideal_amps = node->getFloatValue("amps", 60.0); } else if ( _model == "external" ) { model = FG_EXTERNAL; + ideal_amps = node->getFloatValue("amps", 60.0); } else { model = FG_UNKNOWN; } - volts = node->getDoubleValue("volts"); - amps = node->getDoubleValue("amps"); - rpm_src = node->getStringValue("rpm-source"); + ideal_volts = node->getFloatValue("volts"); int i; for ( i = 0; i < node->nChildren(); ++i ) { @@ -67,7 +72,7 @@ FGElectricalSupplier::FGElectricalSupplier ( SGPropertyNode *node ) { string prop = child->getStringValue(); // cout << " Adding prop = " << prop << endl; add_prop( prop ); - fgSetDouble( prop.c_str(), amps ); + fgSetFloat( prop.c_str(), ideal_amps ); } } @@ -75,24 +80,97 @@ FGElectricalSupplier::FGElectricalSupplier ( SGPropertyNode *node ) { } -double FGElectricalSupplier::get_output() { +float FGElectricalSupplier::apply_load( float amps, float dt ) { if ( model == FG_BATTERY ) { - // cout << "battery amps = " << amps << endl; - return amps; + // calculate amp hours used + float amphrs_used = amps * dt / 3600.0; + + // calculate percent of total available capacity + float percent_used = amphrs_used / amp_hours; + percent_remaining -= percent_used; + if ( percent_remaining < 0.0 ) { + percent_remaining = 0.0; + } else if ( percent_remaining > 1.0 ) { + percent_remaining = 1.0; + } + // cout << "battery percent = " << percent_remaining << endl; + return amp_hours * percent_remaining; } else if ( model == FG_ALTERNATOR ) { // scale alternator output for rpms < 600. For rpms >= 600 // give full output. This is just a WAG, and probably not how // it really works but I'm keeping things "simple" to start. - double rpm = _rpm_node->getDoubleValue(); - double factor = rpm / 600.0; + float rpm = _rpm_node->getFloatValue(); + float factor = rpm / rpm_threshold; if ( factor > 1.0 ) { factor = 1.0; } // cout << "alternator amps = " << amps * factor << endl; - return amps * factor; + float available_amps = ideal_amps * factor; + return available_amps - amps; } else if ( model == FG_EXTERNAL ) { // cout << "external amps = " << 0.0 << endl; - return 0.0; + return available_amps - amps; + } else { + SG_LOG( SG_ALL, SG_ALERT, "unknown supplier type" ); + } + + return 0.0; +} + + +float FGElectricalSupplier::get_output_volts() { + if ( model == FG_BATTERY ) { + // cout << "battery amps = " << amps << endl; + float x = 1.0 - percent_remaining; + float tmp = -(3.0 * x - 1.0); + float factor = (tmp*tmp*tmp*tmp*tmp + 32) / 32; + // cout << "battery % = " << percent_remaining << + // " factor = " << factor << endl; + // percent_remaining -= 0.001; + return ideal_volts * factor; + } else if ( model == FG_ALTERNATOR ) { + // scale alternator output for rpms < 600. For rpms >= 600 + // give full output. This is just a WAG, and probably not how + // it really works but I'm keeping things "simple" to start. + float rpm = _rpm_node->getFloatValue(); + float factor = rpm / rpm_threshold; + if ( factor > 1.0 ) { + factor = 1.0; + } + // cout << "alternator amps = " << amps * factor << endl; + return ideal_volts * factor; + } else if ( model == FG_EXTERNAL ) { + // cout << "external amps = " << 0.0 << endl; + return ideal_volts; + } else { + SG_LOG( SG_ALL, SG_ALERT, "unknown supplier type" ); + } + + return 0.0; +} + + +float FGElectricalSupplier::get_output_amps() { + if ( model == FG_BATTERY ) { + // cout << "battery amp_hours = " << amp_hours << endl; + + // This is a WAG, but produce enough amps to burn the entire + // battery in one minute. + return amp_hours * 60.0; + } else if ( model == FG_ALTERNATOR ) { + // scale alternator output for rpms < 600. For rpms >= 600 + // give full output. This is just a WAG, and probably not how + // it really works but I'm keeping things "simple" to start. + float rpm = _rpm_node->getFloatValue(); + float factor = rpm / rpm_threshold; + if ( factor > 1.0 ) { + factor = 1.0; + } + // cout << "alternator amps = " << ideal_amps * factor << endl; + return ideal_amps * factor; + } else if ( model == FG_EXTERNAL ) { + // cout << "external amps = " << 0.0 << endl; + return ideal_amps; } else { SG_LOG( SG_ALL, SG_ALERT, "unknown supplier type" ); } @@ -118,12 +196,12 @@ FGElectricalBus::FGElectricalBus ( SGPropertyNode *node ) { FGElectricalOutput::FGElectricalOutput ( SGPropertyNode *node ) { kind = FG_OUTPUT; - output_amps = 0.1; // arbitrary default value + load_amps = 0.1; // arbitrary default value name = node->getStringValue("name"); SGPropertyNode *draw = node->getNode("rated-draw"); if ( draw != NULL ) { - output_amps = draw->getDoubleValue(); + load_amps = draw->getFloatValue(); } // cout << "rated draw = " << output_amps << endl; @@ -204,6 +282,10 @@ FGElectricalConnector::FGElectricalConnector ( SGPropertyNode *node, s->add_input( this ); } else if ( s->get_kind() == FG_OUTPUT ) { s->add_input( this ); + } else if ( s->get_kind() == FG_SUPPLIER && + ((FGElectricalSupplier *)s)->get_model() + == FGElectricalSupplier::FG_BATTERY ) { + s->add_output( this ); } else { SG_LOG( SG_ALL, SG_ALERT, "Attempt to connect to something that can't provide an input: " @@ -246,9 +328,31 @@ bool FGElectricalConnector::get_state() { } -FGElectricalSystem::FGElectricalSystem () : +FGElectricalSystem::FGElectricalSystem ( SGPropertyNode *node ) : + name("electrical"), + num(0), + path(""), enabled(false) { + int i; + for ( i = 0; i < node->nChildren(); ++i ) { + SGPropertyNode *child = node->getChild(i); + string cname = child->getName(); + string cval = child->getStringValue(); + if ( cname == "name" ) { + name = cval; + } else if ( cname == "number" ) { + num = child->getIntValue(); + } else if ( cname == "path" ) { + path = cval; + } else { + SG_LOG( SG_SYSTEMS, SG_WARN, + "Error in electrical system config logic" ); + if ( name.length() ) { + SG_LOG( SG_SYSTEMS, SG_WARN, "Section = " << name ); + } + } + } } @@ -259,15 +363,31 @@ FGElectricalSystem::~FGElectricalSystem () { void FGElectricalSystem::init () { config_props = new SGPropertyNode; - SGPropertyNode *path_n = fgGetNode("/sim/systems/electrical/path"); _volts_out = fgGetNode( "/systems/electrical/volts", true ); _amps_out = fgGetNode( "/systems/electrical/amps", true ); - if (path_n) { - SGPath config( globals->get_fg_root() ); - config.append( path_n->getStringValue() ); + // allow the electrical system to be specified via the + // aircraft-set.xml file (for backwards compatibility) or through + // the aircraft-systems.xml file. If a -set.xml entry is + // specified, that overrides the system entry. + SGPropertyNode *path_n = fgGetNode("/sim/systems/electrical/path"); + if ( path_n ) { + if ( path.length() ) { + SG_LOG( SG_ALL, SG_ALERT, + "NOTICE: System manager configuration specifies an " << + "electrical system model from: " << path << " but it is " << + "being overridden by the one specified in the -set.xml " << + "file: " << path_n->getStringValue() ); + } - SG_LOG( SG_ALL, SG_INFO, "Reading electrical system model from " + path = path_n->getStringValue(); + } + + if ( path.length() ) { + SGPath config( globals->get_fg_root() ); + config.append( path ); + + SG_LOG( SG_ALL, SG_ALERT, "Reading electrical system model from " << config.str() ); try { readProperties( config.str(), config_props ); @@ -290,7 +410,11 @@ void FGElectricalSystem::init () { } else { SG_LOG( SG_ALL, SG_WARN, - "No electrical model specified for this model!"); + "No xml-based electrical model specified for this model!"); + } + + if ( !enabled ) { + _amps_out->setDoubleValue(0); } delete config_props; @@ -307,71 +431,118 @@ void FGElectricalSystem::unbind () { void FGElectricalSystem::update (double dt) { if ( !enabled ) { - _amps_out->setDoubleValue(0); return; } - // cout << "Updating electrical system" << endl; + // cout << "Updating electrical system, dt = " << dt << endl; unsigned int i; - // zero everything out before we start + // zero out the voltage before we start, but don't clear the + // requested load values. for ( i = 0; i < suppliers.size(); ++i ) { suppliers[i]->set_volts( 0.0 ); - suppliers[i]->set_load_amps( 0.0 ); } for ( i = 0; i < buses.size(); ++i ) { buses[i]->set_volts( 0.0 ); - buses[i]->set_load_amps( 0.0 ); } for ( i = 0; i < outputs.size(); ++i ) { outputs[i]->set_volts( 0.0 ); - outputs[i]->set_load_amps( 0.0 ); } for ( i = 0; i < connectors.size(); ++i ) { connectors[i]->set_volts( 0.0 ); - connectors[i]->set_load_amps( 0.0 ); } - // for each supplier, propagate the electrical current + // for each "external" supplier, propagate the electrical current for ( i = 0; i < suppliers.size(); ++i ) { - // cout << " Updating: " << suppliers[i]->get_name() << endl; - propagate( suppliers[i], 0.0, " " ); + FGElectricalSupplier *node = (FGElectricalSupplier *)suppliers[i]; + if ( node->get_model() == FGElectricalSupplier::FG_EXTERNAL ) { + float load; + // cout << "Starting propagation: " << suppliers[i]->get_name() + // << endl; + load = propagate( suppliers[i], dt, + node->get_output_volts(), + node->get_output_amps(), + " " ); + + if ( node->apply_load( load, dt ) < 0.0 ) { + cout << "Error drawing more current than available!" << endl; + } + } } - double alt_norm - = fgGetDouble("/systems/electrical/suppliers/alternator") / 60.0; + // for each "alternator" supplier, propagate the electrical + // current + for ( i = 0; i < suppliers.size(); ++i ) { + FGElectricalSupplier *node = (FGElectricalSupplier *)suppliers[i]; + if ( node->get_model() == FGElectricalSupplier::FG_ALTERNATOR) { + float load; + // cout << "Starting propagation: " << suppliers[i]->get_name() + // << endl; + load = propagate( suppliers[i], dt, + node->get_output_volts(), + node->get_output_amps(), + " " ); + + if ( node->apply_load( load, dt ) < 0.0 ) { + cout << "Error drawing more current than available!" << endl; + } + } + } + + // for each "battery" supplier, propagate the electrical + // current + for ( i = 0; i < suppliers.size(); ++i ) { + FGElectricalSupplier *node = (FGElectricalSupplier *)suppliers[i]; + if ( node->get_model() == FGElectricalSupplier::FG_BATTERY ) { + float load; + // cout << "Starting propagation: " << suppliers[i]->get_name() + // << endl; + load = propagate( suppliers[i], dt, + node->get_output_volts(), + node->get_output_amps(), + " " ); + // cout << "battery load = " << load << endl; + + if ( node->apply_load( load, dt ) < 0.0 ) { + cout << "Error drawing more current than available!" << endl; + } + } + } + + float alt_norm + = fgGetFloat("/systems/electrical/suppliers/alternator") / 60.0; // impliment an extremely simplistic voltage model (assumes // certain naming conventions in electrical system config) // FIXME: we probably want to be able to feed power from all // engines if they are running and the master-alt is switched on - double volts = 0.0; + float volts = 0.0; if ( fgGetBool("/controls/engines/engine[0]/master-bat") ) { volts = 24.0; } if ( fgGetBool("/controls/engines/engine[0]/master-alt") ) { - if ( fgGetDouble("/engines/engine[0]/rpm") > 800 ) { - double alt_contrib = 28.0; + if ( fgGetFloat("/engines/engine[0]/rpm") > 800 ) { + float alt_contrib = 28.0; if ( alt_contrib > volts ) { volts = alt_contrib; } - } else if ( fgGetDouble("/engines/engine[0]/rpm") > 200 ) { - double alt_contrib = 20.0; + } else if ( fgGetFloat("/engines/engine[0]/rpm") > 200 ) { + float alt_contrib = 20.0; if ( alt_contrib > volts ) { volts = alt_contrib; } } } - _volts_out->setDoubleValue( volts ); + _volts_out->setFloatValue( volts ); // impliment an extremely simplistic amps model (assumes certain // naming conventions in the electrical system config) ... FIXME: // make this more generic - double amps = 0.0; + float amps = 0.0; if ( fgGetBool("/controls/engines/engine[0]/master-bat") ) { if ( fgGetBool("/controls/engines/engine[0]/master-alt") && - fgGetDouble("/engines/engine[0]/rpm") > 800 ) + fgGetFloat("/engines/engine[0]/rpm") > 800 ) { amps += 40.0 * alt_norm; } @@ -386,7 +557,7 @@ void FGElectricalSystem::update (double dt) { amps = 7.0; } } - _amps_out->setDoubleValue( amps ); + _amps_out->setFloatValue( amps ); } @@ -428,66 +599,99 @@ bool FGElectricalSystem::build () { // propagate the electrical current through the network, returns the // total current drawn by the children of this node. -float FGElectricalSystem::propagate( FGElectricalComponent *node, double val, - string s ) { +float FGElectricalSystem::propagate( FGElectricalComponent *node, double dt, + float input_volts, float input_amps, + string s ) { s += " "; - float current_amps = 0.0; + float total_load = 0.0; // determine the current to carry forward - double volts = 0.0; + float volts = 0.0; if ( !fgGetBool("/systems/electrical/serviceable") ) { volts = 0; - } else if ( node->get_kind() == FG_SUPPLIER ) { - // cout << s << " is a supplier" << endl; - volts = ((FGElectricalSupplier *)node)->get_output(); - } else if ( node->get_kind() == FG_BUS ) { - // cout << s << " is a bus" << endl; - volts = val; - } else if ( node->get_kind() == FG_OUTPUT ) { - // cout << s << " is an output" << endl; - volts = val; + } else if ( node->get_kind() == FGElectricalComponent::FG_SUPPLIER ) { + // cout << s << "is a supplier (" << node->get_name() << ")" << endl; + FGElectricalSupplier *supplier = (FGElectricalSupplier *)node; + if ( supplier->get_model() == FGElectricalSupplier::FG_BATTERY ) { + // cout << s << " (and is a battery)" << endl; + float battery_volts = supplier->get_output_volts(); + if ( battery_volts < (input_volts - 0.1) ) { + // special handling of a battery charge condition + // cout << s << " (and is being charged) in v = " + // << input_volts << " current v = " << battery_volts + // << endl; + supplier->apply_load( -supplier->get_charge_amps(), dt ); + return supplier->get_charge_amps(); + } + } + volts = input_volts; + } else if ( node->get_kind() == FGElectricalComponent::FG_BUS ) { + // cout << s << "is a bus (" << node->get_name() << ")" << endl; + volts = input_volts; + } else if ( node->get_kind() == FGElectricalComponent::FG_OUTPUT ) { + // cout << s << "is an output (" << node->get_name() << ")" << endl; + volts = input_volts; if ( volts > 1.0 ) { // draw current if we have voltage - current_amps = ((FGElectricalOutput *)node)->get_output_amps(); + total_load = node->get_load_amps(); } - } else if ( node->get_kind() == FG_CONNECTOR ) { - // cout << s << " is a connector" << endl; + } else if ( node->get_kind() == FGElectricalComponent::FG_CONNECTOR ) { + // cout << s << "is a connector (" << node->get_name() << ")" << endl; if ( ((FGElectricalConnector *)node)->get_state() ) { - volts = val; + volts = input_volts; } else { volts = 0.0; } - // cout << s << " val = " << volts << endl; + // cout << s << " input_volts = " << volts << endl; } else { SG_LOG( SG_ALL, SG_ALERT, "unkown node type" ); } - if ( volts > node->get_volts() ) { - node->set_volts( volts ); - } - int i; - // publish values to specified properties - for ( i = 0; i < node->get_num_props(); ++i ) { - fgSetDouble( node->get_prop(i).c_str(), node->get_volts() ); - } - // cout << s << node->get_name() << " -> " << node->get_value() << endl; + // if this node has found a stronger power source, update the + // value and propagate to all children + if ( volts > node->get_volts() ) { + node->set_volts( volts ); + for ( i = 0; i < node->get_num_outputs(); ++i ) { + FGElectricalComponent *child = node->get_output(i); + // send current equal to load + total_load += propagate( child, dt, + volts, child->get_load_amps(), + s ); + } - // propagate to all children - for ( i = 0; i < node->get_num_outputs(); ++i ) { - current_amps += propagate( node->get_output(i), volts, s ); - } + // if not an output node, register the downstream current draw + // (sum of all children) with this node. If volts are zero, + // current draw should be zero. + if ( node->get_kind() != FGElectricalComponent::FG_OUTPUT ) { + node->set_load_amps( total_load ); + } - // if not an output node, register the downstream current draw - // with this node. If volts are zero, current draw should be zero. - if ( node->get_kind() != FG_OUTPUT ) { - node->set_load_amps( current_amps ); - } - // cout << s << node->get_name() << " -> " << current_amps << endl; + node->set_available_amps( input_amps - total_load ); - return current_amps; + // publish values to specified properties + for ( i = 0; i < node->get_num_props(); ++i ) { + fgSetFloat( node->get_prop(i).c_str(), node->get_volts() ); + } + + /* + cout << s << node->get_name() << " -> (volts) " << node->get_volts() + << endl; + cout << s << node->get_name() << " -> (load amps) " << total_load + << endl; + cout << s << node->get_name() << " -> (input amps) " << input_amps + << endl; + cout << s << node->get_name() << " -> (extra amps) " + << node->get_available_amps() << endl; + */ + + return total_load; + } else { + // cout << s << "no further propagation" << endl; + return 0.0; + } } diff --git a/src/Systems/electrical.hxx b/src/Systems/electrical.hxx index 0627b83c0..0fb30bf41 100644 --- a/src/Systems/electrical.hxx +++ b/src/Systems/electrical.hxx @@ -46,15 +46,19 @@ SG_USING_STD(vector); class FGElectricalSystem; -#define FG_UNKNOWN -1 -#define FG_SUPPLIER 0 -#define FG_BUS 1 -#define FG_OUTPUT 2 -#define FG_CONNECTOR 3 - // Base class for other electrical components class FGElectricalComponent { +public: + +enum FGElectricalComponentType { + FG_UNKNOWN, + FG_SUPPLIER, + FG_BUS, + FG_OUTPUT, + FG_CONNECTOR +}; + protected: typedef vector comp_list; @@ -63,7 +67,10 @@ protected: int kind; string name; float volts; - float load_amps; + float load_amps; // sum of current draw (load) due to + // this node and all it's children + float available_amps; // available current (after the load + // is subtracted) comp_list inputs; comp_list outputs; @@ -84,6 +91,9 @@ public: inline float get_load_amps() const { return load_amps; } inline void set_load_amps( float val ) { load_amps = val; } + inline float get_available_amps() const { return available_amps; } + inline void set_available_amps( float val ) { available_amps = val; } + inline int get_num_inputs() const { return outputs.size(); } inline FGElectricalComponent *get_input( const int i ) { return inputs[i]; @@ -114,25 +124,44 @@ public: // Electrical supplier class FGElectricalSupplier : public FGElectricalComponent { - SGPropertyNode_ptr _rpm_node; +public: enum FGSupplierType { - FG_BATTERY = 0, - FG_ALTERNATOR = 1, - FG_EXTERNAL = 2 + FG_BATTERY, + FG_ALTERNATOR, + FG_EXTERNAL, + FG_UNKNOWN }; - string rpm_src; - int model; - double volts; - double amps; +private: + + SGPropertyNode_ptr _rpm_node; + + FGSupplierType model; // store supplier type + float ideal_volts; // ideal volts + + // alternator fields + string rpm_src; // property name of alternator power source + float rpm_threshold; // minimal rpm to generate full power + + // alt & ext supplier fields + float ideal_amps; // total amps produced (above rpm threshold). + + // battery fields + float amp_hours; // fully charged battery capacity + float percent_remaining; // percent of charge remaining + float charge_amps; // maximum charge load battery can draw public: FGElectricalSupplier ( SGPropertyNode *node ); ~FGElectricalSupplier () {} - double get_output(); + inline FGSupplierType get_model() const { return model; } + float apply_load( float amps, float dt ); + float get_output_volts(); + float get_output_amps(); + float get_charge_amps() const { return charge_amps; } }; @@ -151,18 +180,10 @@ public: // flexibility class FGElectricalOutput : public FGElectricalComponent { -private: - - // number of amps drawn by this output - float output_amps; - public: FGElectricalOutput ( SGPropertyNode *node ); ~FGElectricalOutput () {} - - inline float get_output_amps() const { return output_amps; } - inline void set_output_amps( float val ) { output_amps = val; } }; @@ -222,7 +243,7 @@ class FGElectricalSystem : public SGSubsystem public: - FGElectricalSystem (); + FGElectricalSystem ( SGPropertyNode *node ); virtual ~FGElectricalSystem (); virtual void init (); @@ -231,7 +252,9 @@ public: virtual void update (double dt); bool build (); - float propagate( FGElectricalComponent *node, double val, string s = "" ); + float propagate( FGElectricalComponent *node, double dt, + float input_volts, float input_amps, + string s = "" ); FGElectricalComponent *find ( const string &name ); protected: @@ -240,6 +263,9 @@ protected: private: + string name; + int num; + string path; SGPropertyNode *config_props; bool enabled;