Implement PID_ADD_EXTRUSION_RATE

Marlin/Configuration_adv.h

@@ -41,7 +41,8 @@
   // if Kc is chosen well, the additional required power due to increased melting should be compensated.
   #define PID_ADD_EXTRUSION_RATE
   #if ENABLED(PID_ADD_EXTRUSION_RATE)
-    #define  DEFAULT_Kc (1) //heating power=Kc*(e_speed)
+    #define DEFAULT_Kc (100) //heating power=Kc*(e_speed)
+    #define LPQ_MAX_LEN 50
   #endif
 #endif
 

Marlin/Marlin.h

@@ -329,6 +329,10 @@ extern int fanSpeed;
   extern int meas_delay_cm; //delay distance
 #endif
 
+#if ENABLED(PID_ADD_EXTRUSION_RATE)
+  extern int lpq_len;
+#endif
+
 #if ENABLED(FWRETRACT)
   extern bool autoretract_enabled;
   extern bool retracted[EXTRUDERS]; // extruder[n].retracted

Marlin/Marlin_main.cpp

@@ -420,6 +420,10 @@ bool target_direction;
   boolean chdkActive = false;
 #endif
 
+#if ENABLED(PID_ADD_EXTRUSION_RATE)
+  int lpq_len = 20;
+#endif
+
 //===========================================================================
 //================================ Functions ================================
 //===========================================================================
@@ -4770,7 +4774,16 @@ inline void gcode_M226() {
 #if ENABLED(PIDTEMP)
 
   /**
-   * M301: Set PID parameters P I D (and optionally C)
+   * M301: Set PID parameters P I D (and optionally C, L)
+   *
+   *   P[float] Kp term
+   *   I[float] Ki term (unscaled)
+   *   D[float] Kd term (unscaled)
+   *
+   * With PID_ADD_EXTRUSION_RATE:
+   *
+   *   C[float] Kc term
+   *   L[float] LPQ length
    */
   inline void gcode_M301() {
 
@@ -4784,6 +4797,8 @@ inline void gcode_M226() {
       if (code_seen('D')) PID_PARAM(Kd, e) = scalePID_d(code_value());
       #if ENABLED(PID_ADD_EXTRUSION_RATE)
         if (code_seen('C')) PID_PARAM(Kc, e) = code_value();
+        if (code_seen('L')) lpq_len = code_value();
+        NOMORE(lpq_len, LPQ_MAX_LEN);
       #endif
 
       updatePID();

Marlin/configuration_store.cpp

@@ -14,7 +14,7 @@
  *
  */
 
-#define EEPROM_VERSION "V20"
+#define EEPROM_VERSION "V21"
 
 /**
  * V19 EEPROM Layout:
@@ -60,6 +60,7 @@
  *  M301 E1 PIDC  Kp[1], Ki[1], Kd[1], Kc[1]
  *  M301 E2 PIDC  Kp[2], Ki[2], Kd[2], Kc[2]
  *  M301 E3 PIDC  Kp[3], Ki[3], Kd[3], Kc[3]
+ *  M301 L        lpq_len
  *
  * PIDTEMPBED:
  *  M304 PID  bedKp, bedKi, bedKd
@@ -227,6 +228,11 @@ void Config_StoreSettings()  {
 
   } // Extruders Loop
 
+  #if DISABLED(PID_ADD_EXTRUSION_RATE)
+    int lpq_len = 20;
+  #endif
+  EEPROM_WRITE_VAR(i, lpq_len);
+
   #if DISABLED(PIDTEMPBED)
     float bedKp = DUMMY_PID_VALUE, bedKi = DUMMY_PID_VALUE, bedKd = DUMMY_PID_VALUE;
   #endif
@@ -393,6 +399,11 @@ void Config_RetrieveSettings() {
       for (int q=16; q--;) EEPROM_READ_VAR(i, dummy);  // 4x Kp, Ki, Kd, Kc
     #endif // !PIDTEMP
 
+    #if DISABLED(PID_ADD_EXTRUSION_RATE)
+      int lpq_len;
+    #endif
+    EEPROM_READ_VAR(i, lpq_len);
+
     #if DISABLED(PIDTEMPBED)
       float bedKp, bedKi, bedKd;
     #endif
@@ -539,6 +550,9 @@ void Config_ResetDefault() {
         PID_PARAM(Kc, e) = DEFAULT_Kc;
       #endif
     }
+    #if ENABLED(PID_ADD_EXTRUSION_RATE)
+      lpq_len = 20; // default last-position-queue size
+    #endif
     // call updatePID (similar to when we have processed M301)
     updatePID();
   #endif // PIDTEMP
@@ -744,7 +758,8 @@ void Config_PrintSettings(bool forReplay) {
             SERIAL_ECHOPAIR(" D", unscalePID_d(PID_PARAM(Kd, i)));
             #if ENABLED(PID_ADD_EXTRUSION_RATE)
               SERIAL_ECHOPAIR(" C", PID_PARAM(Kc, i));
-            #endif      
+              if (i == 0) SERIAL_ECHOPAIR(" L", lpq_len);
+            #endif
             SERIAL_EOL;
           }
         }
@@ -758,7 +773,8 @@ void Config_PrintSettings(bool forReplay) {
         SERIAL_ECHOPAIR(" D", unscalePID_d(PID_PARAM(Kd, 0)));
         #if ENABLED(PID_ADD_EXTRUSION_RATE)
           SERIAL_ECHOPAIR(" C", PID_PARAM(Kc, 0));
-        #endif      
+          SERIAL_ECHOPAIR(" L", lpq_len);
+        #endif
         SERIAL_EOL;
       }
     #endif // PIDTEMP

Marlin/language.h

@@ -200,6 +200,7 @@
 #define MSG_PID_DEBUG_PTERM                 " pTerm "
 #define MSG_PID_DEBUG_ITERM                 " iTerm "
 #define MSG_PID_DEBUG_DTERM                 " dTerm "
+#define MSG_PID_DEBUG_CTERM                 " cTerm "
 #define MSG_INVALID_EXTRUDER_NUM            " - Invalid extruder number !"
 
 #define MSG_HEATER_BED                      "bed"

Marlin/temperature.cpp

@@ -99,6 +99,12 @@ static volatile bool temp_meas_ready = false;
   static float pTerm[EXTRUDERS];
   static float iTerm[EXTRUDERS];
   static float dTerm[EXTRUDERS];
+  #if ENABLED(PID_ADD_EXTRUSION_RATE)
+    static float cTerm[EXTRUDERS];
+    static long last_position[EXTRUDERS];
+    static long lpq[LPQ_MAX_LEN];
+    static int lpq_ptr = 0;
+  #endif
   //int output;
   static float pid_error[EXTRUDERS];
   static float temp_iState_min[EXTRUDERS];
@@ -357,6 +363,9 @@ void updatePID() {
   #if ENABLED(PIDTEMP)
     for (int e = 0; e < EXTRUDERS; e++) {
       temp_iState_max[e] = PID_INTEGRAL_DRIVE_MAX / PID_PARAM(Ki,e);
+      #if ENABLED(PID_ADD_EXTRUSION_RATE)
+        last_position[e] = 0;
+      #endif
     }
   #endif
   #if ENABLED(PIDTEMPBED)
@@ -497,6 +506,23 @@ float get_pid_output(int e) {
         iTerm[e] = PID_PARAM(Ki,e) * temp_iState[e];
 
         pid_output = pTerm[e] + iTerm[e] - dTerm[e];
+
+        #if ENABLED(PID_ADD_EXTRUSION_RATE)
+          cTerm[e] = 0;
+          if (e == active_extruder) {
+            long e_position = st_get_position(E_AXIS);
+            if (e_position > last_position[e]) {
+              lpq[lpq_ptr++] = e_position - last_position[e];
+              last_position[e] = e_position;
+            } else {
+              lpq[lpq_ptr++] = 0;
+            }
+            if (lpq_ptr >= lpq_len) lpq_ptr = 0;
+            cTerm[e] = (lpq[lpq_ptr] / axis_steps_per_unit[E_AXIS]) * Kc;
+            pid_output += cTerm[e];
+          }
+        #endif //PID_ADD_EXTRUSION_RATE
+
         if (pid_output > PID_MAX) {
           if (pid_error[e] > 0) temp_iState[e] -= pid_error[e]; // conditional un-integration
           pid_output = PID_MAX;
@@ -512,18 +538,16 @@ float get_pid_output(int e) {
 
     #if ENABLED(PID_DEBUG)
       SERIAL_ECHO_START;
-      SERIAL_ECHO(MSG_PID_DEBUG);
-      SERIAL_ECHO(e);
-      SERIAL_ECHO(MSG_PID_DEBUG_INPUT);
-      SERIAL_ECHO(current_temperature[e]);
-      SERIAL_ECHO(MSG_PID_DEBUG_OUTPUT);
-      SERIAL_ECHO(pid_output);
-      SERIAL_ECHO(MSG_PID_DEBUG_PTERM);
-      SERIAL_ECHO(pTerm[e]);
-      SERIAL_ECHO(MSG_PID_DEBUG_ITERM);
-      SERIAL_ECHO(iTerm[e]);
-      SERIAL_ECHO(MSG_PID_DEBUG_DTERM);
-      SERIAL_ECHOLN(dTerm[e]);
+      SERIAL_ECHOPAIR(MSG_PID_DEBUG, e);
+      SERIAL_ECHOPAIR(MSG_PID_DEBUG_INPUT, current_temperature[e]);
+      SERIAL_ECHOPAIR(MSG_PID_DEBUG_OUTPUT, pid_output);
+      SERIAL_ECHOPAIR(MSG_PID_DEBUG_PTERM, pTerm[e]);
+      SERIAL_ECHOPAIR(MSG_PID_DEBUG_ITERM, iTerm[e]);
+      SERIAL_ECHOPAIR(MSG_PID_DEBUG_DTERM, dTerm[e]);
+      #if ENABLED(PID_ADD_EXTRUSION_RATE)
+        SERIAL_ECHOPAIR(MSG_PID_DEBUG_CTERM, cTerm[e]);
+      #endif
+      SERIAL_EOL;
     #endif //PID_DEBUG
 
   #else /* PID off */
@@ -837,6 +861,9 @@ void tp_init() {
     #if ENABLED(PIDTEMP)
       temp_iState_min[e] = 0.0;
       temp_iState_max[e] = PID_INTEGRAL_DRIVE_MAX / PID_PARAM(Ki,e);
+      #if ENABLED(PID_ADD_EXTRUSION_RATE)
+        last_position[e] = 0;
+      #endif
     #endif //PIDTEMP
     #if ENABLED(PIDTEMPBED)
       temp_iState_min_bed = 0.0;