🚸 Improved MPCTEMP autotune (MarlinFirmware#25503)

Author: StevilKnevil

Marlin/Configuration.h

@@ -679,14 +679,18 @@
 
 // @section hotend temp
 
-// Enable PIDTEMP for PID control or MPCTEMP for Predictive Model.
-// temperature control. Disable both for bang-bang heating.
-#define PIDTEMP          // See the PID Tuning Guide at https://reprap.org/wiki/PID_Tuning
-//#define MPCTEMP        // ** EXPERIMENTAL **
+/**
+ * Temperature Control
+ *
+ *  (NONE) : Bang-bang heating
+ * PIDTEMP : PID temperature control (~4.1K)
+ * MPCTEMP : Predictive Model temperature control. (~1.8K without auto-tune)
+ */
+#define PIDTEMP           // See the PID Tuning Guide at https://reprap.org/wiki/PID_Tuning
+//#define MPCTEMP         // ** EXPERIMENTAL ** See https://marlinfw.org/docs/features/model_predictive_control.html
 
-#define BANG_MAX 255     // Limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // Limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
-#define PID_K1 0.95      // Smoothing factor within any PID loop
+#define PID_MAX  255      // Limit hotend current while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_K1 0.95       // Smoothing factor within any PID loop
 
 #if ENABLED(PIDTEMP)
   //#define PID_DEBUG             // Print PID debug data to the serial port. Use 'M303 D' to toggle activation.
@@ -708,6 +712,8 @@
     // #define DEFAULT_Ki   1.08
     // #define DEFAULT_Kd 114.00
   #endif
+#else
+  #define BANG_MAX 255    // Limit hotend current while in bang-bang mode; 255=full current
 #endif
 
 /**
@@ -719,11 +725,11 @@
  * @section mpctemp
  */
 #if ENABLED(MPCTEMP)
-  //#define MPC_AUTOTUNE                              // Include a method to do MPC auto-tuning (~5664-5882 bytes of flash)
-  //#define MPC_EDIT_MENU                             // Add MPC editing to the "Advanced Settings" menu. (~1300 bytes of flash)
+  //#define MPC_AUTOTUNE                              // Include a method to do MPC auto-tuning (~6.3K bytes of flash)
+  //#define MPC_EDIT_MENU                             // Add MPC editing to the "Advanced Settings" menu. (~1.3K bytes of flash)
   //#define MPC_AUTOTUNE_MENU                         // Add MPC auto-tuning to the "Advanced Settings" menu. (~350 bytes of flash)
 
-  #define MPC_MAX BANG_MAX                            // (0..255) Current to nozzle while MPC is active.
+  #define MPC_MAX 255                                 // (0..255) Current to nozzle while MPC is active.
   #define MPC_HEATER_POWER { 40.0f }                  // (W) Heat cartridge powers.
 
   #define MPC_INCLUDE_FAN                             // Model the fan speed?
@@ -758,32 +764,30 @@
 //====================== PID > Bed Temperature Control ======================
 //===========================================================================
 
+// @section bed temp
+
+/**
+ * Max Bed Power
+ * Applies to all forms of bed control (PID, bang-bang, and bang-bang with hysteresis).
+ * When set to any value below 255, enables a form of PWM to the bed that acts like a divider
+ * so don't use it unless you are OK with PWM on your bed. (See the comment on enabling PIDTEMPBED)
+ */
+#define MAX_BED_POWER 235 // limits duty cycle to bed; 255=full current
+
 /**
  * PID Bed Heating
  *
- * If this option is enabled set PID constants below.
- * If this option is disabled, bang-bang will be used and BED_LIMIT_SWITCHING will enable hysteresis.
- *
  * The PID frequency will be the same as the extruder PWM.
  * If PID_dT is the default, and correct for the hardware/configuration, that means 7.689Hz,
  * which is fine for driving a square wave into a resistive load and does not significantly
  * impact FET heating. This also works fine on a Fotek SSR-10DA Solid State Relay into a 250W
  * heater. If your configuration is significantly different than this and you don't understand
  * the issues involved, don't use bed PID until someone else verifies that your hardware works.
- * @section bed temp
+ *
+ * With this option disabled, bang-bang will be used. BED_LIMIT_SWITCHING enables hysteresis.
  */
 #define PIDTEMPBED
 
-//#define BED_LIMIT_SWITCHING
-
-/**
- * Max Bed Power
- * Applies to all forms of bed control (PID, bang-bang, and bang-bang with hysteresis).
- * When set to any value below 255, enables a form of PWM to the bed that acts like a divider
- * so don't use it unless you are OK with PWM on your bed. (See the comment on enabling PIDTEMPBED)
- */
-#define MAX_BED_POWER 235 // limits duty cycle to bed; 255=full current
-
 #if ENABLED(PIDTEMPBED)
   //#define MIN_BED_POWER 0
   //#define PID_BED_DEBUG // Print Bed PID debug data to the serial port.
@@ -799,7 +803,9 @@
   // #define DEFAULT_bedKd 305.4
 
   // FIND YOUR OWN: "M303 E-1 C8 S90" to run autotune on the bed at 90 degreesC for 8 cycles.
-#endif // PIDTEMPBED
+#else
+  //#define BED_LIMIT_SWITCHING   // Keep the bed temperature within BED_HYSTERESIS of the target
+#endif
 
 //===========================================================================
 //==================== PID > Chamber Temperature Control ====================

Marlin/src/core/millis_t.h

@@ -28,6 +28,7 @@ typedef uint32_t millis_t;
 #define SEC_TO_MS(N) millis_t((N)*1000UL)
 #define MIN_TO_MS(N) SEC_TO_MS((N)*60UL)
 #define MS_TO_SEC(N) millis_t((N)/1000UL)
+#define MS_TO_SEC_PRECISE(N) (float(N)/1000.0f)
 
 #define PENDING(NOW,SOON) ((int32_t)(NOW-(SOON))<0)
 #define ELAPSED(NOW,SOON) (!PENDING(NOW,SOON))

Marlin/src/gcode/temp/M306.cpp

@@ -42,7 +42,10 @@
  *  R<kelvin/second/kelvin>   Sensor responsiveness (= transfer coefficient / heat capcity).
  *
  *  With MPC_AUTOTUNE:
- *  T                         Autotune the specified or active extruder.
+ *  T                         Autotune the extruder specified with 'E' or the active extruder.
+ *                            S0 : Autotuning method AUTO (default)
+ *                            S1 : Autotuning method DIFFERENTIAL
+ *                            S2 : Autotuning method ASYMPTOTIC
  */
 
 void GcodeSuite::M306() {
@@ -54,8 +57,15 @@ void GcodeSuite::M306() {
 
   #if ENABLED(MPC_AUTOTUNE)
     if (parser.seen_test('T')) {
+      Temperature::MPCTuningType tuning_type;
+      const uint8_t type = parser.byteval('S', 0);
+      switch (type) {
+        case 1: tuning_type = Temperature::MPCTuningType::FORCE_DIFFERENTIAL; break;
+        case 2: tuning_type = Temperature::MPCTuningType::FORCE_ASYMPTOTIC; break;
+        default: tuning_type = Temperature::MPCTuningType::AUTO; break;
+      }
       LCD_MESSAGE(MSG_MPC_AUTOTUNE);
-      thermalManager.MPC_autotune(e);
+      thermalManager.MPC_autotune(e, tuning_type);
       ui.reset_status();
       return;
     }