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⚗️ Temperature Model Predictive Control (#23751)

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This commit is contained in:
tombrazier
2022-04-01 08:14:14 +01:00
committed by Scott Lahteine
parent 3443a9e18b
commit 21c838cb1b
13 changed files with 566 additions and 32 deletions
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300
Marlin/src/module/temperature.cpp
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@@ -141,7 +141,8 @@
#endif
#endif
#if ENABLED(PID_EXTRUSION_SCALING)
#if EITHER(MPCTEMP, PID_EXTRUSION_SCALING)
#include <math.h>
#include "stepper.h"
#endif
@@ -509,10 +510,14 @@ PGMSTR(str_t_heating_failed, STR_T_HEATING_FAILED);
volatile bool Temperature::raw_temps_ready = false;
#if ENABLED(PID_EXTRUSION_SCALING)
int32_t Temperature::last_e_position, Temperature::lpq[LPQ_MAX_LEN];
int32_t Temperature::pes_e_position, Temperature::lpq[LPQ_MAX_LEN];
lpq_ptr_t Temperature::lpq_ptr = 0;
#endif
#if ENABLED(MPCTEMP)
int32_t Temperature::mpc_e_position; // = 0
#endif
#define TEMPDIR(N) ((TEMP_SENSOR_##N##_RAW_LO_TEMP) < (TEMP_SENSOR_##N##_RAW_HI_TEMP) ? 1 : -1)
#define TP_CMP(S,A,B) (TEMPDIR(S) < 0 ? ((A)<(B)) : ((A)>(B)))
@@ -587,8 +592,8 @@ volatile bool Temperature::raw_temps_ready = false;
PID_t tune_pid = { 0, 0, 0 };
celsius_float_t maxT = 0, minT = 10000;
const bool isbed = (heater_id == H_BED);
const bool ischamber = (heater_id == H_CHAMBER);
const bool isbed = (heater_id == H_BED),
ischamber = (heater_id == H_CHAMBER);
#if ENABLED(PIDTEMPCHAMBER)
#define C_TERN(T,A,B) ((T) ? (A) : (B))
@@ -846,6 +851,198 @@ volatile bool Temperature::raw_temps_ready = false;
#endif // HAS_PID_HEATING
#if ENABLED(MPCTEMP)
void Temperature::MPC_autotune() {
auto housekeeping = [] (millis_t& ms, celsius_float_t& current_temp, millis_t& next_report_ms) {
ms = millis();
if (updateTemperaturesIfReady()) { // temp sample ready
current_temp = degHotend(active_extruder);
TERN_(HAS_FAN_LOGIC, manage_extruder_fans(ms));
}
if (ELAPSED(ms, next_report_ms)) {
next_report_ms += 1000UL;
SERIAL_ECHOLNPGM("Temperature ", current_temp);
}
hal.idletask();
};
SERIAL_ECHOLNPGM("Measuring MPC constants for E", active_extruder);
MPCHeaterInfo& hotend = temp_hotend[active_extruder];
MPC_t& constants = hotend.constants;
// move to center of bed, just above bed height and cool with max fan
SERIAL_ECHOLNPGM("Moving to tuning position");
TERN_(HAS_FAN, zero_fan_speeds());
disable_all_heaters();
TERN_(HAS_FAN, set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 255));
TERN_(HAS_FAN, planner.sync_fan_speeds(fan_speed));
gcode.home_all_axes(true);
const xyz_pos_t tuningpos = MPC_TUNING_POS;
do_blocking_move_to(tuningpos);
SERIAL_ECHOLNPGM("Cooling to ambient");
millis_t ms = millis(), next_report_ms = ms, next_test_ms = ms + 10000UL;
celsius_float_t current_temp = degHotend(active_extruder),
ambient_temp = current_temp;
wait_for_heatup = true; // Can be interrupted with M108
while (wait_for_heatup) {
housekeeping(ms, current_temp, next_report_ms);
if (ELAPSED(ms, next_test_ms)) {
if (current_temp >= ambient_temp) {
ambient_temp = (ambient_temp + current_temp) / 2.0f;
break;
}
ambient_temp = current_temp;
next_test_ms += 10000UL;
}
}
TERN_(HAS_FAN, set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 0));
TERN_(HAS_FAN, planner.sync_fan_speeds(fan_speed));
hotend.modeled_ambient_temp = ambient_temp;
SERIAL_ECHOLNPGM("Heating to 200C");
hotend.soft_pwm_amount = MPC_MAX >> 1;
const millis_t heat_start_time = ms;
next_test_ms = ms;
celsius_float_t temp_samples[16];
uint8_t sample_count = 0;
uint16_t sample_distance = 1;
float t1_time = 0;
while (wait_for_heatup) {
housekeeping(ms, current_temp, next_report_ms);
if (ELAPSED(ms, next_test_ms)) {
// record samples between 100C and 200C
if (current_temp >= 100.0f) {
// if there are too many samples, space them more widely
if (sample_count == COUNT(temp_samples)) {
for (uint8_t i = 0; i < COUNT(temp_samples) / 2; i++)
temp_samples[i] = temp_samples[i*2];
sample_count /= 2;
sample_distance *= 2;
}
if (sample_count == 0) t1_time = float(ms - heat_start_time) / 1000.0f;
temp_samples[sample_count++] = current_temp;
}
if (current_temp >= 200.0f) break;
next_test_ms += 1000UL * sample_distance;
}
}
hotend.soft_pwm_amount = 0;
// calculate physical constants from three equally spaced samples
sample_count = (sample_count + 1) / 2 * 2 - 1;
const float t1 = temp_samples[0],
t2 = temp_samples[(sample_count - 1) >> 1],
t3 = temp_samples[sample_count - 1],
asymp_temp = (t2 * t2 - t1 * t3) / (2 * t2 - t1 - t3),
block_responsiveness = -log((t2 - asymp_temp) / (t1 - asymp_temp)) / (sample_distance * (sample_count >> 1));
constants.ambient_xfer_coeff_fan0 = constants.heater_power * MPC_MAX / 255 / (asymp_temp - ambient_temp);
constants.fan255_adjustment = 0.0f;
constants.block_heat_capacity = constants.ambient_xfer_coeff_fan0 / block_responsiveness;
constants.sensor_responsiveness = block_responsiveness / (1.0f - (ambient_temp - asymp_temp) * exp(-block_responsiveness * t1_time) / (t1 - asymp_temp));
hotend.modeled_block_temp = asymp_temp + (ambient_temp - asymp_temp) * exp(-block_responsiveness * (ms - heat_start_time) / 1000.0f);
hotend.modeled_sensor_temp = current_temp;
// let the system stabilise under MPC control then get a better measure of ambient loss without and with fan
SERIAL_ECHOLNPGM("Measuring ambient heatloss at target ", hotend.modeled_block_temp);
hotend.target = hotend.modeled_block_temp;
next_test_ms = ms + MPC_dT * 1000;
constexpr millis_t settle_time = 20000UL,
test_length = 20000UL;
millis_t settle_end_ms = ms + settle_time,
test_end_ms = settle_end_ms + test_length;
float total_energy_fan0 = 0.0f;
#if HAS_FAN
bool fan0_done = false;
float total_energy_fan255 = 0.0f;
#endif
float last_temp = current_temp;
while (wait_for_heatup) {
housekeeping(ms, current_temp, next_report_ms);
if (ELAPSED(ms, next_test_ms)) {
// use MPC to control the temperature, let it settle for 30s and then track power output for 10s
hotend.soft_pwm_amount = (int)get_pid_output_hotend(active_extruder) >> 1;
if (ELAPSED(ms, settle_end_ms) && !ELAPSED(ms, test_end_ms) && TERN1(HAS_FAN, !fan0_done))
total_energy_fan0 += constants.heater_power * hotend.soft_pwm_amount / 127 * MPC_dT + (last_temp - current_temp) * constants.block_heat_capacity;
#if HAS_FAN
else if (ELAPSED(ms, test_end_ms) && !fan0_done) {
SERIAL_ECHOLNPGM("Measuring ambient heatloss with full fan");
set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 255);
planner.sync_fan_speeds(fan_speed);
settle_end_ms = ms + settle_time;
test_end_ms = settle_end_ms + test_length;
fan0_done = true;
}
else if (ELAPSED(ms, settle_end_ms) && !ELAPSED(ms, test_end_ms))
total_energy_fan255 += constants.heater_power * hotend.soft_pwm_amount / 127 * MPC_dT + (last_temp - current_temp) * constants.block_heat_capacity;
#endif
else if (ELAPSED(ms, test_end_ms)) break;
last_temp = current_temp;
next_test_ms += MPC_dT * 1000;
}
if (!WITHIN(current_temp, hotend.target - 15.0f, hotend.target + 15.0f)) {
SERIAL_ECHOLNPGM("Temperature error while measuring ambient loss");
break;
}
}
const float power_fan0 = total_energy_fan0 * 1000 / test_length;
constants.ambient_xfer_coeff_fan0 = power_fan0 / (hotend.target - ambient_temp);
#if HAS_FAN
const float power_fan255 = total_energy_fan255 * 1000 / test_length,
ambient_xfer_coeff_fan255 = power_fan255 / (hotend.target - ambient_temp);
constants.fan255_adjustment = ambient_xfer_coeff_fan255 - constants.ambient_xfer_coeff_fan0;
#endif
hotend.target = 0.0f;
hotend.soft_pwm_amount = 0;
TERN_(HAS_FAN, set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 0));
TERN_(HAS_FAN, planner.sync_fan_speeds(fan_speed));
if (!wait_for_heatup) SERIAL_ECHOLNPGM("Test was interrupted");
wait_for_heatup = false;
SERIAL_ECHOLNPGM("Done");
/* <-- add a slash to enable
SERIAL_ECHOLNPGM("t1_time ", t1_time);
SERIAL_ECHOLNPGM("sample_count ", sample_count);
SERIAL_ECHOLNPGM("sample_distance ", sample_distance);
for (uint8_t i = 0; i < sample_count; i++)
SERIAL_ECHOLNPGM("sample ", i, " : ", temp_samples[i]);
SERIAL_ECHOLNPGM("t1 ", t1, " t2 ", t2, " t3 ", t3);
SERIAL_ECHOLNPGM("asymp_temp ", asymp_temp);
SERIAL_ECHOLNPAIR_F("block_responsiveness ", block_responsiveness, 4);
//*/
SERIAL_ECHOLNPGM("MPC_BLOCK_HEAT_CAPACITY ", constants.block_heat_capacity);
SERIAL_ECHOLNPAIR_F("MPC_SENSOR_RESPONSIVENESS ", constants.sensor_responsiveness, 4);
SERIAL_ECHOLNPAIR_F("MPC_AMBIENT_XFER_COEFF ", constants.ambient_xfer_coeff_fan0, 4);
TERN_(HAS_FAN, SERIAL_ECHOLNPAIR_F("MPC_AMBIENT_XFER_COEFF_FAN255 ", ambient_xfer_coeff_fan255, 4));
}
#endif // MPCTEMP
int16_t Temperature::getHeaterPower(const heater_id_t heater_id) {
switch (heater_id) {
#if HAS_HEATED_BED
@@ -1101,7 +1298,7 @@ void Temperature::min_temp_error(const heater_id_t heater_id) {
pid_reset.set(ee);
}
else if (pid_error > PID_FUNCTIONAL_RANGE) {
pid_output = BANG_MAX;
pid_output = PID_MAX;
pid_reset.set(ee);
}
else {
@@ -1128,9 +1325,9 @@ void Temperature::min_temp_error(const heater_id_t heater_id) {
work_pid[ee].Kc = 0;
if (this_hotend) {
const long e_position = stepper.position(E_AXIS);
if (e_position > last_e_position) {
lpq[lpq_ptr] = e_position - last_e_position;
last_e_position = e_position;
if (e_position > pes_e_position) {
lpq[lpq_ptr] = e_position - pes_e_position;
pes_e_position = e_position;
}
else
lpq[lpq_ptr] = 0;
@@ -1173,7 +1370,86 @@ void Temperature::min_temp_error(const heater_id_t heater_id) {
}
#endif
#else // No PID enabled
#elif ENABLED(MPCTEMP)
MPCHeaterInfo& hotend = temp_hotend[ee];
MPC_t& constants = hotend.constants;
// At startup, initialize modeled temperatures
if (isnan(hotend.modeled_block_temp)) {
hotend.modeled_ambient_temp = min(30.0f, hotend.celsius); // cap initial value at reasonable max room temperature of 30C
hotend.modeled_block_temp = hotend.modeled_sensor_temp = hotend.celsius;
}
#if HOTENDS == 1
constexpr bool this_hotend = true;
#else
const bool this_hotend = (ee == active_extruder);
#endif
float ambient_xfer_coeff = constants.ambient_xfer_coeff_fan0;
#if ENABLED(MPC_INCLUDE_FAN)
const uint8_t fan_index = ANY(MPC_FAN_0_ACTIVE_HOTEND, MPC_FAN_0_ALL_HOTENDS) ? 0 : ee;
const float fan_fraction = TERN_(MPC_FAN_0_ACTIVE_HOTEND, !this_hotend ? 0.0f : ) fan_speed[fan_index] * RECIPROCAL(255);
ambient_xfer_coeff += fan_fraction * constants.fan255_adjustment;
#endif
if (this_hotend) {
const int32_t e_position = stepper.position(E_AXIS);
const float e_speed = (e_position - mpc_e_position) * planner.mm_per_step[E_AXIS] / MPC_dT;
// the position can appear to make big jumps when, e.g. homing
if (fabs(e_speed) > planner.settings.max_feedrate_mm_s[E_AXIS])
mpc_e_position = e_position;
else if (e_speed > 0.0f) { // ignore retract/recover moves
ambient_xfer_coeff += e_speed * FILAMENT_HEAT_CAPACITY_PERMM;
mpc_e_position = e_position;
}
}
// update the modeled temperatures
float blocktempdelta = hotend.soft_pwm_amount * constants.heater_power * (MPC_dT / 127) / constants.block_heat_capacity;
blocktempdelta += (hotend.modeled_ambient_temp - hotend.modeled_block_temp) * ambient_xfer_coeff * MPC_dT / constants.block_heat_capacity;
hotend.modeled_block_temp += blocktempdelta;
const float sensortempdelta = (hotend.modeled_block_temp - hotend.modeled_sensor_temp) * (constants.sensor_responsiveness * MPC_dT);
hotend.modeled_sensor_temp += sensortempdelta;
// Any delta between hotend.modeled_sensor_temp and hotend.celsius is either model
// error diverging slowly or (fast) noise. Slowly correct towards this temperature and noise will average out.
const float delta_to_apply = (hotend.celsius - hotend.modeled_sensor_temp) * (MPC_SMOOTHING_FACTOR);
hotend.modeled_block_temp += delta_to_apply;
hotend.modeled_sensor_temp += delta_to_apply;
// only correct ambient when close to steady state (output power is not clipped or asymptotic temperature is reached)
if (WITHIN(hotend.soft_pwm_amount, 1, 126) || fabs(blocktempdelta + delta_to_apply) < (MPC_STEADYSTATE * MPC_dT))
hotend.modeled_ambient_temp += delta_to_apply > 0.f ? max(delta_to_apply, MPC_MIN_AMBIENT_CHANGE * MPC_dT) : min(delta_to_apply, -MPC_MIN_AMBIENT_CHANGE * MPC_dT);
float power = 0.0;
if (hotend.target != 0 && TERN1(HEATER_IDLE_HANDLER, !heater_idle[ee].timed_out)) {
// plan power level to get to target temperature in 2 seconds
power = (hotend.target - hotend.modeled_block_temp) * constants.block_heat_capacity / 2.0f;
power -= (hotend.modeled_ambient_temp - hotend.modeled_block_temp) * ambient_xfer_coeff;
}
float pid_output = power * 254.0f / constants.heater_power + 1.0f; // ensure correct quantization into a range of 0 to 127
pid_output = constrain(pid_output, 0, MPC_MAX);
/* <-- add a slash to enable
static uint32_t nexttime = millis() + 1000;
if (ELAPSED(millis(), nexttime)) {
nexttime += 1000;
SERIAL_ECHOLNPGM("block temp ", hotend.modeled_block_temp,
", celsius ", hotend.celsius,
", blocktempdelta ", blocktempdelta,
", delta_to_apply ", delta_to_apply,
", ambient ", hotend.modeled_ambient_temp,
", power ", power,
", pid_output ", pid_output,
", pwm ", (int)pid_output >> 1);
}
//*/
#else // No PID or MPC enabled
const bool is_idling = TERN0(HEATER_IDLE_HANDLER, heater_idle[ee].timed_out);
const float pid_output = (!is_idling && temp_hotend[ee].celsius < temp_hotend[ee].target) ? BANG_MAX : 0;
@@ -2178,7 +2454,7 @@ void Temperature::init() {
TERN_(PROBING_HEATERS_OFF, paused_for_probing = false);
#if BOTH(PIDTEMP, PID_EXTRUSION_SCALING)
last_e_position = 0;
pes_e_position = 0;
#endif
// Init (and disable) SPI thermocouples
@@ -2248,6 +2524,10 @@ void Temperature::init() {
));
#endif
#if ENABLED(MPCTEMP)
HOTEND_LOOP() temp_hotend[e].modeled_block_temp = NAN;
#endif
#if HAS_HEATER_0
#ifdef BOARD_OPENDRAIN_MOSFETS
OUT_WRITE_OD(HEATER_0_PIN, HEATER_0_INVERTING);