/* Class PropInt
*
* This class contains the constructor to create an instance of
* a proportional plus integral(PI) controller and
* the methods needed to use this controller in control loops in the
* time domain, Laplace transform s domain or the z-transform z domain.
*
* This class is a subclass of the superclass BlackBox.
*
* Author: Michael Thomas Flanagan.
*
* Created: August 2002
* Updated: 17 April 2003, 3 May 2005, 2 July 2006, 27 February 2008, 6 April 2008, 7 November 2009
* 24 May 2010
*
* DOCUMENTATION:
* See Michael T Flanagan's JAVA library on-line web page:
* http://www.ee.ucl.ac.uk/~mflanaga/java/PropInt.html
* http://www.ee.ucl.ac.uk/~mflanaga/java/
*
* Copyright (c) 2002 - 2010 Michael Thomas Flanagan
*
* PERMISSION TO COPY:
* Permission to use, copy and modify this software and its documentation for
* NON-COMMERCIAL purposes is granted, without fee, provided that an acknowledgement
* to the author, Michael Thomas Flanagan at www.ee.ac.uk/~mflanaga, appears in all copies.
*
* Dr Michael Thomas Flanagan makes no representations about the suitability
* or fitness of the software for any or for a particular purpose.
* Michael Thomas Flanagan shall not be liable for any damages suffered
* as a result of using, modifying or distributing this software or its derivatives.
*
***************************************************************************************/
package flanagan.control;
import flanagan.complex.Complex;
import flanagan.complex.ComplexPoly;
import flanagan.plot.Plot;
import flanagan.plot.PlotGraph;
public class PropInt extends BlackBox{
private double kp = 1.0D; // proportional gain
private double ti = Double.POSITIVE_INFINITY; // integral time constant
private double ki = 0.0D; // integral gain
// Constructor - unit proportional gain, zero integral gain
public PropInt(){
super("PropInt");
super.setSnumer(new ComplexPoly(0.0D, 1.0D));
super.setSdenom(new ComplexPoly(0.0D, 1.0D));
super.setZtransformMethod(1);
super.addDeadTimeExtras();
}
// Set the proportional gain
public void setKp(double kp){
super.sNumer.resetCoeff(1, new Complex(kp, 0.0));
super.calcPolesZerosS();
super.addDeadTimeExtras();
}
// Set the integral gain
public void setKi(double ki){
this.ki=ki;
this.ti=this.kp/ki;
super.sNumer.resetCoeff(0, new Complex(ki, 0.0));
super.calcPolesZerosS();
super.addDeadTimeExtras();
}
// Set the integral time constant
public void setTi(double ti){
this.ti=ti;
this.ki=this.kp/ti;
super.sNumer.resetCoeff(0, new Complex(ki, 0.0));
super.calcPolesZerosS();
super.addDeadTimeExtras();
}
// Get the proprtional gain
public double getKp(){
return this.kp;
}
// Get the integral gain
public double getKi(){
return this.ki;
}
// Get the integral time constant
public double getTi(){
return this.ti;
}
// Perform z transform using an already set delta T
public void zTransform(){
super.deadTimeWarning("zTransform");
if(super.deltaT==0.0D)System.out.println("z-transform attempted in PropInt with a zero sampling period");
if(super.ztransMethod==0){
this.mapstozAdHoc();
}
else{
super.zDenom = new ComplexPoly(1);
Complex[] coef = Complex.oneDarray(2);
coef[0].reset(-1.0D,0.0D);
coef[1].reset(1.0D,0.0D);
super.zDenom.resetPoly(coef);
Complex[] zPoles = Complex.oneDarray(1);
zPoles[0].reset(1.0D, 0.0D);
super.zNumer = new ComplexPoly(1);
Complex[] zZeros = Complex.oneDarray(1);
double kit = this.ki*super.deltaT;
switch(this.integMethod){
// trapezium rule
case 0: coef[0].reset(kit/2.0D - this.kp, 0.0D);
coef[1].reset(kit/2.0D + this.kp, 0.0D);
super.zNumer.resetPoly(coef);
zZeros[0].reset((this.kp - kit/2.0D)/(this.kp + kit/2.0D), 0.0D);
break;
// backward rectangular rule
case 1: coef[0].reset(-this.kp, 0.0D);
coef[1].reset(kit + this.kp, 0.0D);
super.zNumer.resetPoly(coef);
zZeros[0].reset(this.kp/(this.kp + kit), 0.0D);
break;
// foreward rectangular rule
case 2: coef[0].reset(this.kp - kit, 0.0D);
coef[1].reset(this.kp, 0.0D);
super.zNumer.resetPoly(coef);
zZeros[0].reset((this.kp - kit)/this.kp, 0.0D);
break;
default: System.out.println("Integration method option in PropInt must be 0,1 or 2");
System.out.println("It was set at "+integMethod);
System.out.println("z-transform not performed");
}
}
}
// Perform z transform setting delta T
public void zTransform(double deltaT){
super.setDeltaT(deltaT);
this.zTransform();
}
// Plots the time course for a step input
public void stepInput(double stepMag, double finalTime){
// Calculate time course outputs
int n = 50; // number of points on plot
double incrT = finalTime/(double)(n-1); // plotting increment
double cdata[][] = new double [2][n]; // plotting array
double sum = 0.0D; // integration sum
cdata[0][0]=0.0D;
for(int i=1; i<n; i++){
cdata[0][i]=cdata[0][i-1]+incrT;
}
double kpterm = this.kp*stepMag;
for(int i=0; i<n; i++){
sum += ki*incrT*stepMag;
cdata[1][i] = kpterm + sum;
cdata[0][i] += super.deadTime;
}
// Plot
PlotGraph pg = new PlotGraph(cdata);
pg.setGraphTitle("Step Input Transient: Step magnitude = "+stepMag);
pg.setGraphTitle2(this.getName());
pg.setXaxisLegend("Time");
pg.setXaxisUnitsName("s");
pg.setYaxisLegend("Output");
pg.setPoint(0);
pg.plot();
}
// Plots the time course for a unit step input
public void stepInput(double finalTime){
this.stepInput(1.0D, finalTime);
}
// Plots the time course for an nth order ramp input (at^n)
public void rampInput(double rampGradient, int rampOrder, double finalTime){
// Calculate time course outputs
int n = 50; // number of points on plot
double incrT = finalTime/(double)(n-1); // plotting increment
double cdata[][] = new double [2][n]; // plotting array
double sum = 0.0D; // integration sum
cdata[0][0]=0.0D;
cdata[1][0]=0.0D;
for(int i=1; i<n; i++){
cdata[0][i]=cdata[0][i-1]+incrT;
sum += rampGradient*(Math.pow(cdata[0][i],rampOrder+1) - Math.pow(cdata[0][i-1],rampOrder+1))/(double)(rampOrder+1);
cdata[1][i] = this.kp*rampGradient*Math.pow(cdata[0][i],rampOrder) + sum;
}
for(int i=0; i<n; i++){
cdata[0][i] += super.deadTime;
}
// Plot
PlotGraph pg = new PlotGraph(cdata);
pg.setGraphTitle("Ramp (a.t^n) Input Transient: ramp gradient (a) = "+rampGradient + " ramp order (n) = " + rampOrder);
pg.setGraphTitle2(this.getName());
pg.setXaxisLegend("Time");
pg.setXaxisUnitsName("s");
pg.setYaxisLegend("Output");
pg.setPoint(0);
pg.plot();
}
// Plots the time course for an nth order ramp input (t^n)
public void rampInput(int rampOrder, double finalTime){
double rampGradient = 1.0D;
this.rampInput(rampGradient, rampOrder, finalTime);
}
// Plots the time course for a first order ramp input (at)
public void rampInput(double rampGradient, double finalTime){
int rampOrder = 1;
this.rampInput(rampGradient, rampOrder, finalTime);
}
// Plots the time course for a unit ramp input (t)
public void rampInput(double finalTime){
double rampGradient = 1.0D;
int rampOrder = 1;
this.rampInput(rampGradient, rampOrder, finalTime);
}
// Get the s-domain output for a given s-value and a given input.
public Complex getOutputS(Complex sValue, Complex iinput){
super.sValue=sValue;
super.inputS=iinput;
Complex term = super.sValue.times(this.kp);
term = term.plus(this.ki);
term = term.over(super.sValue);
super.outputS=term.times(super.inputS);
if(super.deadTime!=0.0D)super.outputS = super.outputS.times(Complex.exp(super.sValue.times(-super.deadTime)));
return super.outputS;
}
// Get the s-domain output for the stored input and s-value.
public Complex getOutputS(){
Complex term = super.sValue.times(this.kp);
term = term.plus(this.ki);
term = term.over(super.sValue);
super.outputS=term.times(super.inputS);
if(super.deadTime!=0.0D)super.outputS = super.outputS.times(Complex.exp(super.sValue.times(-super.deadTime)));
return super.outputS;
}
// Calculate the current time domain output for a given input and given time
// resets deltaT
public void calcOutputT(double ttime, double inp){
super.setInputT(ttime, inp);
this.calcOutputT();
}
// calculate the output for the stored sampled input and time.
public void calcOutputT(){
super.deadTimeWarning("calcOutputT()");
// proportional term
super.outputT[super.sampLen-1]=this.kp*super.inputT[super.sampLen-1];
// + integral term
if(super.forgetFactor==1.0D){
switch(super.integMethod){
// trapezium Rule
case 0: super.integrationSum += (super.inputT[super.sampLen-1]+super.inputT[super.sampLen-2])*super.deltaT/2.0D;
break;
// backward rectangular rule
case 1: super.integrationSum += super.inputT[super.sampLen-1]*super.deltaT;
break;
// foreward rectangular rule
case 2: super.integrationSum += super.inputT[super.sampLen-2]*super.deltaT;
break;
default: System.out.println("Integration method option in PropInt must be 0,1 or 2");
System.out.println("It was set at "+super.integMethod);
System.out.println("getOutput not performed");
}
}
else{
switch(super.integMethod){
// trapezium Rule
case 0: super.integrationSum=0.0D;
for(int i=1; i<super.sampLen; i++){
super.integrationSum+=Math.pow(super.forgetFactor, super.sampLen-1-i)*(super.inputT[i-1]+super.inputT[i])*super.deltaT/2.0D;
};
break;
// backward rectangular rule
case 1: super.integrationSum=0.0D;
for(int i=1; i<sampLen; i++){
super.integrationSum+=Math.pow(super.forgetFactor, super.sampLen-1-i)*(super.inputT[i])*super.deltaT;
};
break;
// foreward rectangular rule
case 2: super.integrationSum=0.0D;
for(int i=1; i<super.sampLen; i++){
super.integrationSum+=Math.pow(super.forgetFactor, super.sampLen-1-i)*(super.inputT[i-1])*super.deltaT;
};
break;
default: System.out.println("Integration method option in PropInt must be 0,1 or 2");
System.out.println("It was set at "+super.integMethod);
System.out.println("getOutput not performed");
}
}
super.outputT[super.sampLen-1] += this.ki*super.integrationSum;
}
// Deep copy
public PropInt copy(){
if(this==null){
return null;
}
else{
PropInt bb = new PropInt();
this.copyBBvariables(bb);
bb.kp = this.kp;
bb.ti = this.ti;
bb.ki = this.ki;
return bb;
}
}
// Clone - overrides Java.Object method clone
public Object clone(){
return (Object)this.copy();
}
}