Model predictive temperature control

Marlin/Configuration.h

@@ -589,10 +589,12 @@
 //===========================================================================
 //============================= PID Settings ================================
 //===========================================================================
-// PID Tuning Guide here: https://reprap.org/wiki/PID_Tuning
 
-// Comment the following line to disable PID and enable bang-bang.
-#define PIDTEMP
+// 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 **
+
 #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
@@ -614,7 +616,45 @@
     #define DEFAULT_Ki   1.08
     #define DEFAULT_Kd 114.00
   #endif
-#endif // PIDTEMP
+#endif
+
+/**
+ * Model Predictive Control for hotend
+ *
+ * Use a physical model of the hotend to control temperature. When configured correctly
+ * this gives better responsiveness and stability than PID and it also removes the need
+ * for PID_EXTRUSION_SCALING and PID_FAN_SCALING. Use M306 to autotune the model.
+ */
+#if ENABLED(MPCTEMP)
+  #define MPC_MAX BANG_MAX                            // (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?
+
+  // Measured physical constants from M306
+  #define MPC_BLOCK_HEAT_CAPACITY { 16.7f }           // (J/K) Heat block heat capacities.
+  #define MPC_SENSOR_RESPONSIVENESS { 0.22f }         // (K/s per ∆K) Rate of change of sensor temperature from heat block.
+  #define MPC_AMBIENT_XFER_COEFF { 0.068f }           // (W/K) Heat transfer coefficients from heat block to room air with fan off.
+  #if ENABLED(MPC_INCLUDE_FAN)
+    #define MPC_AMBIENT_XFER_COEFF_FAN255 { 0.097f }  // (W/K) Heat transfer coefficients from heat block to room air with fan on full.
+  #endif
+
+  // For one fan and multiple hotends MPC needs to know how to apply the fan cooling effect.
+  #if ENABLED(MPC_INCLUDE_FAN)
+    //#define MPC_FAN_0_ALL_HOTENDS
+    //#define MPC_FAN_0_ACTIVE_HOTEND
+  #endif
+
+  #define FILAMENT_HEAT_CAPACITY_PERMM 5.6e-3f        // 0.0056 J/K/mm for 1.75mm PLA (0.0149 J/K/mm for 2.85mm PLA).
+  //#define FILAMENT_HEAT_CAPACITY_PERMM 3.6e-3f      // 0.0036 J/K/mm for 1.75mm PETG (0.0094 J/K/mm for 2.85mm PETG).
+
+  // Advanced options
+  #define MPC_SMOOTHING_FACTOR 0.5f                   // (0.0...1.0) Noisy temperature sensors may need a lower value for stabilization.
+  #define MPC_MIN_AMBIENT_CHANGE 1.0f                 // (K/s) Modeled ambient temperature rate of change, when correcting model inaccuracies.
+  #define MPC_STEADYSTATE 0.5f                        // (K/s) Temperature change rate for steady state logic to be enforced.
+
+  #define MPC_TUNING_POS { X_CENTER, Y_CENTER, 1.0f } // (mm) M306 Autotuning position, ideally bed center just above the surface.
+#endif
 
 //===========================================================================
 //====================== PID > Bed Temperature Control ======================

Marlin/src/HAL/ESP32/HAL.cpp

@@ -209,19 +209,19 @@ void MarlinHAL::adc_init() {
   adc1_config_width(ADC_WIDTH_12Bit);
 
   // Configure channels only if used as (re-)configuring a pin for ADC that is used elsewhere might have adverse effects
-  TERN_(HAS_TEMP_ADC_0, adc1_set_attenuation(get_channel(TEMP_0_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_1, adc1_set_attenuation(get_channel(TEMP_1_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_2, adc1_set_attenuation(get_channel(TEMP_2_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_3, adc1_set_attenuation(get_channel(TEMP_3_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_4, adc1_set_attenuation(get_channel(TEMP_4_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_5, adc1_set_attenuation(get_channel(TEMP_5_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_6, adc2_set_attenuation(get_channel(TEMP_6_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_ADC_7, adc3_set_attenuation(get_channel(TEMP_7_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_HEATED_BED, adc1_set_attenuation(get_channel(TEMP_BED_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_CHAMBER, adc1_set_attenuation(get_channel(TEMP_CHAMBER_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_PROBE, adc1_set_attenuation(get_channel(TEMP_PROBE_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_COOLER, adc1_set_attenuation(get_channel(TEMP_COOLER_PIN), ADC_ATTEN_11db));
-  TERN_(HAS_TEMP_BOARD, adc1_set_attenuation(get_channel(TEMP_BOARD_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_0,        adc1_set_attenuation(get_channel(TEMP_0_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_1,        adc1_set_attenuation(get_channel(TEMP_1_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_2,        adc1_set_attenuation(get_channel(TEMP_2_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_3,        adc1_set_attenuation(get_channel(TEMP_3_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_4,        adc1_set_attenuation(get_channel(TEMP_4_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_5,        adc1_set_attenuation(get_channel(TEMP_5_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_6,        adc2_set_attenuation(get_channel(TEMP_6_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_ADC_7,        adc3_set_attenuation(get_channel(TEMP_7_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_HEATED_BED,        adc1_set_attenuation(get_channel(TEMP_BED_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_CHAMBER,      adc1_set_attenuation(get_channel(TEMP_CHAMBER_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_PROBE,        adc1_set_attenuation(get_channel(TEMP_PROBE_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_COOLER,       adc1_set_attenuation(get_channel(TEMP_COOLER_PIN), ADC_ATTEN_11db));
+  TERN_(HAS_TEMP_BOARD,        adc1_set_attenuation(get_channel(TEMP_BOARD_PIN), ADC_ATTEN_11db));
   TERN_(FILAMENT_WIDTH_SENSOR, adc1_set_attenuation(get_channel(FILWIDTH_PIN), ADC_ATTEN_11db));
 
   // Note that adc2 is shared with the WiFi module, which has higher priority, so the conversion may fail.

Marlin/src/gcode/gcode.cpp

@@ -787,6 +787,10 @@ void GcodeSuite::process_parsed_command(const bool no_ok/*=false*/) {
         case 305: M305(); break;                                  // M305: Set user thermistor parameters
       #endif
 
+      #if ENABLED(MPCTEMP)
+        case 306: M306(); break;                                  // M306: MPC autotune
+      #endif
+
       #if ENABLED(REPETIER_GCODE_M360)
         case 360: M360(); break;                                  // M360: Firmware settings
       #endif

Marlin/src/gcode/gcode.h

@@ -215,6 +215,7 @@
  * M303 - PID relay autotune S<temperature> sets the target temperature. Default 150C. (Requires PIDTEMP)
  * M304 - Set bed PID parameters P I and D. (Requires PIDTEMPBED)
  * M305 - Set user thermistor parameters R T and P. (Requires TEMP_SENSOR_x 1000)
+ * M306 - MPC autotune. (Requires MPCTEMP)
  * M309 - Set chamber PID parameters P I and D. (Requires PIDTEMPCHAMBER)
  * M350 - Set microstepping mode. (Requires digital microstepping pins.)
  * M351 - Toggle MS1 MS2 pins directly. (Requires digital microstepping pins.)
@@ -928,6 +929,11 @@ class GcodeSuite {
     static void M305();
   #endif
 
+  #if ENABLED(MPCTEMP)
+    static void M306();
+    static void M306_report(const bool forReplay=true);
+  #endif
+
   #if ENABLED(PIDTEMPCHAMBER)
     static void M309();
     static void M309_report(const bool forReplay=true);

Marlin/src/gcode/temp/M306.cpp

@@ -0,0 +1,86 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2022 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(MPCTEMP)
+
+#include "../gcode.h"
+#include "../../module/temperature.h"
+
+/**
+ * M306: MPC settings and autotune
+ *
+ *  T                         Autotune the active extruder.
+ *
+ *  A<watts/kelvin>           Ambient heat transfer coefficient (no fan).
+ *  C<joules/kelvin>          Block heat capacity.
+ *  E<extruder>               Extruder number to set. (Default: E0)
+ *  F<watts/kelvin>           Ambient heat transfer coefficient (fan on full).
+ *  P<watts>                  Heater power.
+ *  R<kelvin/second/kelvin>   Sensor responsiveness (= transfer coefficient / heat capcity).
+ */
+
+void GcodeSuite::M306() {
+  if (parser.seen_test('T')) { thermalManager.MPC_autotune(); return; }
+
+  if (parser.seen("ACFPR")) {
+    const heater_id_t hid = (heater_id_t)parser.intval('E', 0);
+    MPC_t &constants = thermalManager.temp_hotend[hid].constants;
+    if (parser.seenval('P')) constants.heater_power = parser.value_float();
+    if (parser.seenval('C')) constants.block_heat_capacity = parser.value_float();
+    if (parser.seenval('R')) constants.sensor_responsiveness = parser.value_float();
+    if (parser.seenval('A')) constants.ambient_xfer_coeff_fan0 = parser.value_float();
+    #if ENABLED(MPC_INCLUDE_FAN)
+      if (parser.seenval('F')) constants.fan255_adjustment = parser.value_float() - constants.ambient_xfer_coeff_fan0;
+    #endif
+    return;
+  }
+
+  HOTEND_LOOP() {
+    SERIAL_ECHOLNPGM("MPC constants for hotend ", e);
+    MPC_t& constants = thermalManager.temp_hotend[e].constants;
+    SERIAL_ECHOLNPGM("Heater power: ", constants.heater_power);
+    SERIAL_ECHOLNPGM("Heatblock heat capacity: ", constants.block_heat_capacity);
+    SERIAL_ECHOLNPAIR_F("Sensor responsivness: ", constants.sensor_responsiveness, 4);
+    SERIAL_ECHOLNPAIR_F("Ambient heat transfer coeff. (no fan): ", constants.ambient_xfer_coeff_fan0, 4);
+    #if ENABLED(MPC_INCLUDE_FAN)
+      SERIAL_ECHOLNPAIR_F("Ambient heat transfer coeff. (full fan): ", constants.ambient_xfer_coeff_fan0 + constants.fan255_adjustment, 4);
+    #endif
+  }
+}
+
+void GcodeSuite::M306_report(const bool forReplay/*=true*/) {
+  report_heading(forReplay, F("Model predictive control"));
+  HOTEND_LOOP() {
+    report_echo_start(forReplay);
+    MPC_t& constants = thermalManager.temp_hotend[e].constants;
+    SERIAL_ECHOPGM("  M306 E", e);
+    SERIAL_ECHOPAIR_F(" P", constants.heater_power, 2);
+    SERIAL_ECHOPAIR_F(" C", constants.block_heat_capacity, 2);
+    SERIAL_ECHOPAIR_F(" R", constants.sensor_responsiveness, 4);
+    SERIAL_ECHOPAIR_F(" A", constants.ambient_xfer_coeff_fan0, 4);
+    SERIAL_ECHOLNPAIR_F(" F", constants.ambient_xfer_coeff_fan0 + constants.fan255_adjustment, 4);
+  }
+}
+
+#endif // MPCTEMP

Marlin/src/inc/SanityCheck.h

@@ -1391,6 +1391,26 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
   #error "You must set DISPLAY_CHARSET_HD44780 to JAPANESE, WESTERN or CYRILLIC for your LCD controller."
 #endif
 
+/**
+ * Extruder temperature control algorithm - There can be only one!
+ */
+#if BOTH(PIDTEMP, MPCTEMP)
+  #error "Only enable PIDTEMP or MPCTEMP, but not both."
+#endif
+
+#if ENABLED(MPC_INCLUDE_FAN)
+  #if FAN_COUNT < 1
+    #error "MPC_INCLUDE_FAN requires at least one fan."
+  #endif
+  #if FAN_COUNT < HOTENDS
+    #if COUNT_ENABLED(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) > 1
+      #error "Enable either MPC_FAN_0_ALL_HOTENDS or MPC_FAN_0_ACTIVE_HOTEND, not both."
+    #elif NONE(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND)
+      #error "MPC_INCLUDE_FAN requires MPC_FAN_0_ALL_HOTENDS or MPC_FAN_0_ACTIVE_HOTEND for one fan with multiple hotends."
+    #endif
+  #endif
+#endif
+
 /**
  * Bed Heating Options - PID vs Limit Switching
  */

Marlin/src/lcd/extui/anycubic_chiron/chiron_tft.cpp

@@ -85,7 +85,7 @@ void ChironTFT::Startup() {
   // opt_enable FIL_RUNOUT_PULLUP
   TFTSer.begin(115200);
 
-  // wait for the TFT panel to initialise and finish the animation
+  // Wait for the TFT panel to initialize and finish the animation
   safe_delay(1000);
 
   // There are different panels for the Chiron with slightly different commands

Marlin/src/lcd/extui/anycubic_i3mega/anycubic_i3mega_lcd.cpp

@@ -85,7 +85,7 @@ void AnycubicTFTClass::OnSetup() {
   SENDLINE_DBG_PGM("J17", "TFT Serial Debug: Main board reset... J17"); // J17 Main board reset
   delay_ms(10);
 
-  // initialise the state of the key pins running on the tft
+  // Init the state of the key pins running on the TFT
   #if ENABLED(SDSUPPORT) && PIN_EXISTS(SD_DETECT)
     SET_INPUT_PULLUP(SD_DETECT_PIN);
   #endif

Marlin/src/module/settings.cpp

@@ -554,6 +554,13 @@ typedef struct SettingsDataStruct {
     uint8_t ui_language;                                // M414 S
   #endif
 
+  //
+  // Model predictive control
+  //
+  #if ENABLED(MPCTEMP)
+    MPC_t mpc_constants[HOTENDS];                       // M306
+  #endif
+
 } SettingsData;
 
 //static_assert(sizeof(SettingsData) <= MARLIN_EEPROM_SIZE, "EEPROM too small to contain SettingsData!");
@@ -1559,6 +1566,14 @@ void MarlinSettings::postprocess() {
       EEPROM_WRITE(ui.language);
     #endif
 
+    //
+    // Model predictive control
+    //
+    #if ENABLED(MPCTEMP)
+      HOTEND_LOOP()
+        EEPROM_WRITE(thermalManager.temp_hotend[e].constants);
+    #endif
+
     //
     // Report final CRC and Data Size
     //
@@ -2510,6 +2525,16 @@ void MarlinSettings::postprocess() {
       }
       #endif
 
+      //
+      // Model predictive control
+      //
+      #if ENABLED(MPCTEMP)
+      {
+        HOTEND_LOOP()
+          EEPROM_READ(thermalManager.temp_hotend[e].constants);
+      }
+      #endif
+
       //
       // Validate Final Size and CRC
       //
@@ -3219,6 +3244,37 @@ void MarlinSettings::reset() {
   #endif
 
   TERN_(EXTENSIBLE_UI, ExtUI::onFactoryReset());
+
+  //
+  // Model predictive control
+  //
+  #if ENABLED(MPCTEMP)
+    constexpr float _mpc_heater_power[] = MPC_HEATER_POWER;
+    constexpr float _mpc_block_heat_capacity[] = MPC_BLOCK_HEAT_CAPACITY;
+    constexpr float _mpc_sensor_responsiveness[] = MPC_SENSOR_RESPONSIVENESS;
+    constexpr float _mpc_ambient_xfer_coeff[] = MPC_AMBIENT_XFER_COEFF;
+    #if ENABLED(MPC_INCLUDE_FAN)
+      constexpr float _mpc_ambient_xfer_coeff_fan255[] = MPC_AMBIENT_XFER_COEFF_FAN255;
+    #endif
+
+    static_assert(COUNT(_mpc_heater_power) == HOTENDS, "MPC_HEATER_POWER must have HOTENDS items.");
+    static_assert(COUNT(_mpc_block_heat_capacity) == HOTENDS, "MPC_BLOCK_HEAT_CAPACITY must have HOTENDS items.");
+    static_assert(COUNT(_mpc_sensor_responsiveness) == HOTENDS, "MPC_SENSOR_RESPONSIVENESS must have HOTENDS items.");
+    static_assert(COUNT(_mpc_ambient_xfer_coeff) == HOTENDS, "MPC_AMBIENT_XFER_COEFF must have HOTENDS items.");
+    #if ENABLED(MPC_INCLUDE_FAN)
+      static_assert(COUNT(_mpc_ambient_xfer_coeff_fan255) == HOTENDS, "MPC_AMBIENT_XFER_COEFF_FAN255 must have HOTENDS items.");
+    #endif
+
+    HOTEND_LOOP() {
+      thermalManager.temp_hotend[e].constants.heater_power = _mpc_heater_power[e];
+      thermalManager.temp_hotend[e].constants.block_heat_capacity = _mpc_block_heat_capacity[e];
+      thermalManager.temp_hotend[e].constants.sensor_responsiveness = _mpc_sensor_responsiveness[e];
+      thermalManager.temp_hotend[e].constants.ambient_xfer_coeff_fan0 = _mpc_ambient_xfer_coeff[e];
+      #if ENABLED(MPC_INCLUDE_FAN)
+        thermalManager.temp_hotend[e].constants.fan255_adjustment = _mpc_ambient_xfer_coeff_fan255[e] - _mpc_ambient_xfer_coeff[e];
+      #endif
+    }
+  #endif
 }
 
 #if DISABLED(DISABLE_M503)
@@ -3495,6 +3551,11 @@ void MarlinSettings::reset() {
     #endif
 
     TERN_(HAS_MULTI_LANGUAGE, gcode.M414_report(forReplay));
+
+    //
+    // Model predictive control
+    //
+    TERN_(MPCTEMP, gcode.M306_report(forReplay));
   }
 
 #endif // !DISABLE_M503