Simple PID Controller with Integral Windup Supports creating a diagnostics message to send to a GUI
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Revision 5:1206105e20bd, committed 2017-10-31
- Comitter:
- batchee7
- Date:
- Tue Oct 31 03:46:43 2017 +0000
- Parent:
- 4:b590bd8fec6f
- Commit message:
- Final updates;
Changed in this revision
PidController.cpp | Show annotated file Show diff for this revision Revisions of this file |
PidController.h | Show annotated file Show diff for this revision Revisions of this file |
--- a/PidController.cpp Wed Oct 04 01:13:49 2017 +0000 +++ b/PidController.cpp Tue Oct 31 03:46:43 2017 +0000 @@ -1,13 +1,13 @@ #include "mbed.h" #include "PidController.h" -PidController::PidController(bool sqrt){ +PidController::PidController(char c){ elapsedTime =0; mode = MANUAL; - squareRootOuptut = sqrt; + diagChar = c; } -int PidController::Calculate(float SP, float PV, float ManualMV) +float PidController::Calculate(float SP, float PV, float ManualMV) { float CV; //(mm/s) Control Variable float IntegralAction; // Integral Contribution to Output @@ -17,35 +17,37 @@ { CV = ManualMV; //Write Manual Manipulated Variable accumError = 0; + prevError = 0; } else { //Calc error error = SP - PV; IntegralAction = K_i*(accumError + error); - DerivativeAction = K_d*(PV - lastInput); + //DerivativeAction = K_d*(PV - lastInput); + DerivativeAction = K_d*(error - prevError); //-- PID Calculation - if (SP) { - CV = K_p*error + IntegralAction - DerivativeAction; - if ((CV > 0) && squareRootOuptut)CV = sqrt(CV); - } + if (SP) + { + CV = bias + K_p*error + IntegralAction + DerivativeAction; + if (CV>0) {CV = sqrt(CV);} + } else + { + CV= 0; + accumError = 0; + } - CV= 0; - - //-- Only allow the Controller to integrate if the output isnt saturated if ((CV < maxLimit) || (CV > minLimit)) { accumError += error; } - - //-- Told to stop! - if (!SP) accumError = 0; //-- Save Current Input for Next Loop - lastInput = PV; + //lastInput = PV; + prevError = error; //Check to See Output is Within Limits if (CV > maxLimit){CV= maxLimit;} @@ -56,38 +58,41 @@ //-- Make message to send to GUI if (collectDiagnostics){BuildDiagMessage(SP,PV, CV, K_p*error, IntegralAction, DerivativeAction);} - return (int)(CV); + return CV; } -void PidController::UpdateSettings(float Bias, float PropGain, float IntGain, float DiffGain, float OutputMin, float OutputMax, float OutputScale){ +void PidController::UpdateSettings(float Bias, float PropGain, float IntGain, float DiffGain, float OutputMin, float OutputMax){ bias = Bias; K_p = PropGain; K_i = IntGain; K_d = DiffGain; minLimit = OutputMin; maxLimit = OutputMax; - scalar = OutputScale; + return; } void PidController::UpdateSettings(float OutputMin, float OutputMax){ minLimit = OutputMin; maxLimit = OutputMax; + return; } void PidController::StartDiag(void){ elapsedTime =0; collectDiagnostics = true; + return; } void PidController::EndDiag(void){ collectDiagnostics = false; - + return; } void PidController::BuildDiagMessage(float SetPoint, float ProcessVar, float PWM, float PropAction, float IntAction, float DifAction){ - sprintf(diagMsg, "P %d %0.4f %0.4f %0.1f %0.4f %0.4f %0.4f\n", elapsedTime, SetPoint, ProcessVar, PWM, PropAction, IntAction, DifAction); + //sprintf(diagMsg, "%c %d %0.4f %0.4f %0.1f %0.4f %0.4f %0.4f\n", diagChar, elapsedTime, SetPoint, ProcessVar, PWM, PropAction, IntAction, DifAction); + sprintf(diagMsg, "%c %d %0.4f %0.4f %0.1f 0.0 0.0 0.0\n", diagChar, elapsedTime, SetPoint, ProcessVar, PWM); elapsedTime += RATE; - if (elapsedTime > 32000){sprintf(diagMsg, "R");} + return; }
--- a/PidController.h Wed Oct 04 01:13:49 2017 +0000 +++ b/PidController.h Tue Oct 31 03:46:43 2017 +0000 @@ -41,10 +41,9 @@ #ifndef PidController_H #define PidController_H #include "mbed.h" -#include "math.h" //-- Constants used in system -const int RATE = 100; //--(ms) Time that Calculate mehtod is being called +const int RATE = 20; //--(ms) Time that Calculate mehtod is being called const int AUTOMATIC = 0; //-- In automatic then PID Controls Output const int MANUAL = 1; //-- In Manual then User Controls Output directly @@ -57,14 +56,14 @@ /** Constructor * */ - PidController(bool); + PidController(char); /** Performs the PID Calculation * @param SP - Setpoint (target value) units depends on what PID is controlling * @param PV - Process Variable (feedback/ measure value) units depends on what PID is controlling * @return Returns If Controller is in Automatic then returns PID controlled signal. In manual returns the user SP multipled by scalar. */ - int Calculate(float SP, float PV, float ManualMV); + float Calculate(float SP, float PV, float ManualMV); /** Update Internal Settings * @param Bias - Added to the PID Calculation @@ -75,7 +74,7 @@ * @param OutputMax - Maximum Limit for the Output (units are same as setpoint) * @param OutputScale - Multiplier at End of PID loop to convert from engineering units to signal (eg PWM duty cycle) */ - void UpdateSettings(float Bias, float PropGain, float IntGain, float DiffGain, float OutputMin, float OutputMax, float OutputScale); + void UpdateSettings(float Bias, float PropGain, float IntGain, float DiffGain, float OutputMin, float OutputMax); /** Update Internal Settings * @param OutputMin - Minimum Limit for the Output (units are same as setpoint) @@ -126,13 +125,14 @@ int elapsedTime; //-- For PID Calculations - bool squareRootOuptut; - float bias, scalar; + char diagChar; + float bias; float error; float lastInput; float accumError; float minLimit, maxLimit; float K_p,K_i,K_d; + float prevError; }; #endif