Update

- Now using 2-stage integral anti-windup strategy
- Better organized compute code
- Some cleanup and documentation updates

Author: Dlloydev

README.md

@@ -17,7 +17,7 @@ Development began with a fork of the Arduino PID Library. Modifications and new
 - [x] Variable Proportional on Error to Proportional on Measurement parameter `POn`
 - [x] Variable Derivative on Error to Derivative on Measurement parameter `DOn`
 - [x] New PID Query Functions: `GetPterm();`  `GetIterm();`  `GetDterm();`
-- [x] Integral windup prevention when output exceeds limits
+- [x] 2-stage Integral windup prevention when output exceeds limits
 - [x] New REVERSE mode only changes sign of `error` and `dInput`
 - [x] Uses `float` instead of `double`
 

library.json

@@ -1,7 +1,7 @@
 {
   "name": "QuickPID",
-  "version": "2.4.3",
-  "description": "A fast PID controller with an AutoTune dynamic object, 10 tunung rules, Integral anti-windup, TIMER Mode, variable Proportional and Derivative on Error to Measurement and full-featured Arduino analogWrite compatibility for ESP32 and ESP32-S2.",
+  "version": "2.4.4",
+  "description": "A fast PID controller with AutoTune dynamic object, 10 tuning rules, Integral anti-windup, TIMER Mode and mixing of Proportional and Derivative on Error to Measurement. Also includes analogWrite compatibility for ESP32 and ESP32-S2.",
   "keywords": "PID, controller, signal",
   "repository":
   {
@@ -20,7 +20,7 @@
   "license": "MIT",
   "homepage": "https://github.com/Dlloydev/QuickPID",
   "dependencies": {
-    "QuickPID": "~2.4.3"
+    "QuickPID": "~2.4.4"
   },
   "frameworks": "*",
   "platforms": "*"

library.properties

@@ -1,10 +1,9 @@
 name=QuickPID
-version=2.4.3
+version=2.4.4
 author=David Lloyd
 maintainer=David Lloyd <[email protected]>
-sentence=A fast PID controller with AutoTune, integral anti-windup and variable controls for Proportional and Derivative on Error to Measurement.
-paragraph=A fast PID controller with an AutoTune dynamic object, 10 tunung rules, Integral anti-windup, TIMER Mode, variable Proportional and Derivative on Error to Measurement and full-featured Arduino analogWrite compatibility for ESP32 and ESP32-S2.
+sentence=A fast PID controller with AutoTune dynamic object, 10 tuning rules, Integral anti-windup, TIMER Mode and mixing of Proportional and Derivative on Error to Measurement.
+paragraph=Also includes analogWrite compatibility for ESP32 and ESP32-S2.
 category=Signal Input/Output
 url=https://github.com/Dlloydev/QuickPID
 architectures=*
-includes=QuickPID.h,analogWrite.h

src/QuickPID.cpp

@@ -1,5 +1,5 @@
 /**********************************************************************************
-   QuickPID Library for Arduino - Version 2.4.3
+   QuickPID Library for Arduino - Version 2.4.4
    by dlloydev https://github.com/Dlloydev/QuickPID
    Based on the Arduino PID Library and work on AutoTunePID class
    by gnalbandian (Gonzalo). Licensed under the MIT License.
@@ -65,18 +65,13 @@ bool QuickPID::Compute() {
     dmTerm = kdm * dInput;
     deTerm = -kde * error;
 
-    outputSum += iTerm;
-    if (outputSum > outMax) iTerm -= outputSum - outMax; // integral anti-windup
-    else if (outputSum < outMin) iTerm += outMin - outputSum;
+    outputSum += iTerm;                                                           // include integral amount
+    if (outputSum > outMax) outputSum -= outputSum - outMax;                      // early integral anti-windup at outMax
+    else if (outputSum < outMin) outputSum += outMin - outputSum;                 // early integral anti-windup at outMin
+    outputSum = constrain(outputSum, outMin, outMax);                             // integral anti-windup clamp
+    outputSum = constrain(outputSum - pmTerm, outMin, outMax);                    // include pmTerm and clamp
+    *myOutput = constrain(outputSum + peTerm + dmTerm - deTerm, outMin, outMax);  // totalize, clamp and drive the output
 
-    float output = peTerm;
-    outputSum -= pmTerm;
-    outputSum = constrain(outputSum, outMin, outMax);
-
-    output += outputSum - deTerm + dmTerm;
-    output = constrain(output, outMin, outMax);
-
-    *myOutput = output;
     lastInput = input;
     lastTime = now;
     return true;
@@ -399,26 +394,14 @@ void AutoTunePID::setAutoTuneConstants(float * kp, float * ki, float * kd) {
 }
 
 /* Utility************************************************************/
-
+// https://github.com/avandalen/avdweb_AnalogReadFast
 int QuickPID::analogReadFast(int ADCpin) {
 #if defined(__AVR_ATmega328P__)
   byte ADCregOriginal = ADCSRA;
   ADCSRA = (ADCSRA & B11111000) | 5; // 32 prescaler
   int adc = analogRead(ADCpin);
   ADCSRA = ADCregOriginal;
   return adc;
-#elif defined(__AVR_ATtiny_Zero_One__) || defined(__AVR_ATmega_Zero__)
-  byte ADCregOriginal = ADC0_CTRLC;
-  ADC0_CTRLC = 0x54; // reduced cap, Vdd ref, 32 prescaler
-  int adc = analogRead(ADCpin);
-  ADC0_CTRLC = ADCregOriginal;
-  return adc;
-#elif defined(__AVR_DA__)
-  byte ADCregOriginal = ADC0.CTRLC;
-  ADC0.CTRLC = ADC_PRESC_DIV32_gc; // 32 prescaler
-  int adc = analogRead(ADCpin);
-  ADC0.CTRLC = ADCregOriginal;
-  return adc;
 #else
   return analogRead(ADCpin);
 # endif