Author: Jon S. Berndt
Date started: 6/17/2006
- ------------- Copyright (C) 2006 Jon S. Berndt (jsb@hal-pc.org) -------------
+ ------------- Copyright (C) 2006 Jon S. Berndt (jon@jsbsim.org) -------------
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
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGPID.h"
+#include "input_output/FGXMLElement.h"
+#include <string>
+#include <iostream>
+
+using namespace std;
namespace JSBSim {
-static const char *IdSrc = "$Id$";
+static const char *IdSrc = "$Id: FGPID.cpp,v 1.20 2012/05/10 12:10:48 jberndt Exp $";
static const char *IdHdr = ID_PID;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGPID::FGPID(FGFCS* fcs, Element* element) : FGFCSComponent(fcs, element)
{
- dt = fcs->GetState()->Getdt();
+ string kp_string, ki_string, kd_string;
Kp = Ki = Kd = 0.0;
- P_out = D_out = I_out = 0.0;
+ KpPropertyNode = 0;
+ KiPropertyNode = 0;
+ KdPropertyNode = 0;
+ KpPropertySign = 1.0;
+ KiPropertySign = 1.0;
+ KdPropertySign = 1.0;
+ I_out_total = 0.0;
Input_prev = Input_prev2 = 0.0;
Trigger = 0;
+ ProcessVariableDot = 0;
+ IsStandard = false;
+ IntType = eNone; // No integrator initially defined.
+
+ string pid_type = element->GetAttributeValue("type");
+
+ if (pid_type == "standard") IsStandard = true;
+
+ if ( element->FindElement("kp") ) {
+ kp_string = element->FindElementValue("kp");
+ if (!is_number(kp_string)) { // property
+ if (kp_string[0] == '-') {
+ KpPropertySign = -1.0;
+ kp_string.erase(0,1);
+ }
+ KpPropertyNode = PropertyManager->GetNode(kp_string);
+ } else {
+ Kp = element->FindElementValueAsNumber("kp");
+ }
+ }
+
+ if ( element->FindElement("ki") ) {
+ ki_string = element->FindElementValue("ki");
+
+ string integ_type = element->FindElement("ki")->GetAttributeValue("type");
+ if (integ_type == "rect") { // Use rectangular integration
+ IntType = eRectEuler;
+ } else if (integ_type == "trap") { // Use trapezoidal integration
+ IntType = eTrapezoidal;
+ } else if (integ_type == "ab2") { // Use Adams Bashforth 2nd order integration
+ IntType = eAdamsBashforth2;
+ } else if (integ_type == "ab3") { // Use Adams Bashforth 3rd order integration
+ IntType = eAdamsBashforth3;
+ } else { // Use default Adams Bashforth 2nd order integration
+ IntType = eAdamsBashforth2;
+ }
+
+ if (!is_number(ki_string)) { // property
+ if (ki_string[0] == '-') {
+ KiPropertySign = -1.0;
+ ki_string.erase(0,1);
+ }
+ KiPropertyNode = PropertyManager->GetNode(ki_string);
+ } else {
+ Ki = element->FindElementValueAsNumber("ki");
+ }
+ }
+
+ if ( element->FindElement("kd") ) {
+ kd_string = element->FindElementValue("kd");
+ if (!is_number(kd_string)) { // property
+ if (kd_string[0] == '-') {
+ KdPropertySign = -1.0;
+ kd_string.erase(0,1);
+ }
+ KdPropertyNode = PropertyManager->GetNode(kd_string);
+ } else {
+ Kd = element->FindElementValueAsNumber("kd");
+ }
+ }
+
+ if (element->FindElement("pvdot")) {
+ ProcessVariableDot = PropertyManager->GetNode(element->FindElementValue("pvdot"));
+ }
- if (element->FindElement("kp")) Kp = element->FindElementValueAsNumber("kp");
- if (element->FindElement("ki")) Ki = element->FindElementValueAsNumber("ki");
- if (element->FindElement("kd")) Kd = element->FindElementValueAsNumber("kd");
if (element->FindElement("trigger")) {
Trigger = PropertyManager->GetNode(element->FindElementValue("trigger"));
}
bool FGPID::Run(void )
{
+ double I_out_delta = 0.0;
+ double Dval = 0;
+
Input = InputNodes[0]->getDoubleValue() * InputSigns[0];
- P_out = Kp * (Input - Input_prev);
- I_out = Ki * dt * Input;
- D_out = (Kd / dt) * (Input - 2*Input_prev + Input_prev2);
+ if (KpPropertyNode != 0) Kp = KpPropertyNode->getDoubleValue() * KpPropertySign;
+ if (KiPropertyNode != 0) Ki = KiPropertyNode->getDoubleValue() * KiPropertySign;
+ if (KdPropertyNode != 0) Kd = KdPropertyNode->getDoubleValue() * KdPropertySign;
+
+ if (ProcessVariableDot) {
+ Dval = ProcessVariableDot->getDoubleValue();
+ } else {
+ Dval = (Input - Input_prev)/dt;
+ }
- if (Trigger != 0) {
- double test = Trigger->getDoubleValue();
- if (fabs(test) > 0.000001) {
- I_out = 0.0;
+ // Do not continue to integrate the input to the integrator if a wind-up
+ // condition is sensed - that is, if the property pointed to by the trigger
+ // element is non-zero. Reset the integrator to 0.0 if the Trigger value
+ // is negative.
+
+ double test = 0.0;
+ if (Trigger != 0) test = Trigger->getDoubleValue();
+
+ if (fabs(test) < 0.000001) {
+ switch(IntType) {
+ case eRectEuler:
+ I_out_delta = Ki * dt * Input; // Normal rectangular integrator
+ break;
+ case eTrapezoidal:
+ I_out_delta = (Ki/2.0) * dt * (Input + Input_prev); // Trapezoidal integrator
+ break;
+ case eAdamsBashforth2:
+ I_out_delta = Ki * dt * (1.5*Input - 0.5*Input_prev); // 2nd order Adams Bashforth integrator
+ break;
+ case eAdamsBashforth3: // 3rd order Adams Bashforth integrator
+ I_out_delta = (Ki/12.0) * dt * (23.0*Input - 16.0*Input_prev + 5.0*Input_prev2);
+ break;
+ case eNone:
+ // No integator is defined or used.
+ I_out_delta = 0.0;
+ break;
}
}
+ if (test < 0.0) I_out_total = 0.0; // Reset integrator to 0.0
+
+ I_out_total += I_out_delta;
+
+ if (IsStandard) {
+ Output = Kp * (Input + I_out_total + Kd*Dval);
+ } else {
+ Output = Kp*Input + I_out_total + Kd*Dval;
+ }
+
Input_prev = Input;
Input_prev2 = Input_prev;
- Output += P_out + I_out + D_out;
-
Clip();
if (IsOutput) SetOutput();
if (debug_lvl & 1) { // Standard console startup message output
if (from == 0) { // Constructor
if (InputSigns[0] < 0)
- cout << " INPUT: -" << InputNodes[0]->getName() << endl;
+ cout << " INPUT: -" << InputNodes[0]->GetName() << endl;
else
- cout << " INPUT: " << InputNodes[0]->getName() << endl;
+ cout << " INPUT: " << InputNodes[0]->GetName() << endl;
- if (IsOutput) cout << " OUTPUT: " << OutputNode->getName() << 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
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