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/**
* Marlin 3D Printer Firmware
* Copyright (c) 2020 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/MarlinConfigPre.h"
#if ENABLED(PROBE_TEMP_COMPENSATION)
#include "probe_temp_comp.h"
#include <math.h>
ProbeTempComp temp_comp;
int16_t ProbeTempComp::z_offsets_probe[cali_info_init[TSI_PROBE].measurements], // = {0}
ProbeTempComp::z_offsets_bed[cali_info_init[TSI_BED].measurements]; // = {0}
#if ENABLED(USE_TEMP_EXT_COMPENSATION)
int16_t ProbeTempComp::z_offsets_ext[cali_info_init[TSI_EXT].measurements]; // = {0}
#endif
int16_t *ProbeTempComp::sensor_z_offsets[TSI_COUNT] = {
ProbeTempComp::z_offsets_probe, ProbeTempComp::z_offsets_bed
#if ENABLED(USE_TEMP_EXT_COMPENSATION)
, ProbeTempComp::z_offsets_ext
#endif
};
const temp_calib_t ProbeTempComp::cali_info[TSI_COUNT] = {
cali_info_init[TSI_PROBE], cali_info_init[TSI_BED]
#if ENABLED(USE_TEMP_EXT_COMPENSATION)
, cali_info_init[TSI_EXT]
#endif
};
constexpr xyz_pos_t ProbeTempComp::park_point;
constexpr xy_pos_t ProbeTempComp::measure_point;
constexpr int ProbeTempComp::probe_calib_bed_temp;
uint8_t ProbeTempComp::calib_idx; // = 0
float ProbeTempComp::init_measurement; // = 0.0
void ProbeTempComp::clear_offsets(const TempSensorID tsi) {
LOOP_L_N(i, cali_info[tsi].measurements)
sensor_z_offsets[tsi][i] = 0;
calib_idx = 0;
}
bool ProbeTempComp::set_offset(const TempSensorID tsi, const uint8_t idx, const int16_t offset) {
if (idx >= cali_info[tsi].measurements) return false;
sensor_z_offsets[tsi][idx] = offset;
return true;
}
void ProbeTempComp::print_offsets() {
LOOP_L_N(s, TSI_COUNT) {
float temp = cali_info[s].start_temp;
for (int16_t i = -1; i < cali_info[s].measurements; ++i) {
serialprintPGM(s == TSI_BED ? PSTR("Bed") :
#if ENABLED(USE_TEMP_EXT_COMPENSATION)
s == TSI_EXT ? PSTR("Extruder") :
#endif
PSTR("Probe")
);
SERIAL_ECHOLNPAIR(
" temp: ", temp,
"C; Offset: ", i < 0 ? 0.0f : sensor_z_offsets[s][i], " um"
);
temp += cali_info[s].temp_res;
}
}
}
void ProbeTempComp::prepare_new_calibration(const float &init_meas_z) {
calib_idx = 0;
init_measurement = init_meas_z;
}
void ProbeTempComp::push_back_new_measurement(const TempSensorID tsi, const float &meas_z) {
switch (tsi) {
case TSI_PROBE:
case TSI_BED:
//case TSI_EXT:
if (calib_idx >= cali_info[tsi].measurements) return;
sensor_z_offsets[tsi][calib_idx++] = static_cast<int16_t>(meas_z * 1000.0f - init_measurement * 1000.0f);
default: break;
}
}
bool ProbeTempComp::finish_calibration(const TempSensorID tsi) {
if (tsi != TSI_PROBE && tsi != TSI_BED) return false;
if (calib_idx < 3) {
SERIAL_ECHOLNPGM("!Insufficient measurements (min. 3).");
clear_offsets(tsi);
return false;
}
const uint8_t measurements = cali_info[tsi].measurements;
const float start_temp = cali_info[tsi].start_temp,
res_temp = cali_info[tsi].temp_res;
int16_t * const data = sensor_z_offsets[tsi];
// Extrapolate
float k, d;
if (calib_idx < measurements) {
SERIAL_ECHOLNPAIR("Got ", calib_idx, " measurements. ");
if (linear_regression(tsi, k, d)) {
SERIAL_ECHOPGM("Applying linear extrapolation");
calib_idx--;
for (; calib_idx < measurements; ++calib_idx) {
const float temp = start_temp + float(calib_idx) * res_temp;
data[calib_idx] = static_cast<int16_t>(k * temp + d);
}
}
else {
// Simply use the last measured value for higher temperatures
SERIAL_ECHOPGM("Failed to extrapolate");
const int16_t last_val = data[calib_idx];
for (; calib_idx < measurements; ++calib_idx)
data[calib_idx] = last_val;
}
SERIAL_ECHOLNPGM(" for higher temperatures.");
}
// Sanity check
for (calib_idx = 0; calib_idx < measurements; ++calib_idx) {
// Restrict the max. offset
if (abs(data[calib_idx]) > 2000) {
SERIAL_ECHOLNPGM("!Invalid Z-offset detected (0-2).");
clear_offsets(tsi);
return false;
}
// Restrict the max. offset difference between two probings
if (calib_idx > 0 && abs(data[calib_idx - 1] - data[calib_idx]) > 800) {
SERIAL_ECHOLNPGM("!Invalid Z-offset between two probings detected (0-0.8).");
clear_offsets(TSI_PROBE);
return false;
}
}
return true;
}
void ProbeTempComp::compensate_measurement(const TempSensorID tsi, const float &temp, float &meas_z) {
if (WITHIN(temp, cali_info[tsi].start_temp, cali_info[tsi].end_temp))
meas_z -= get_offset_for_temperature(tsi, temp);
}
float ProbeTempComp::get_offset_for_temperature(const TempSensorID tsi, const float &temp) {
const uint8_t measurements = cali_info[tsi].measurements;
const float start_temp = cali_info[tsi].start_temp,
res_temp = cali_info[tsi].temp_res;
const int16_t * const data = sensor_z_offsets[tsi];
auto point = [&](uint8_t i) {
return xy_float_t({start_temp + i*res_temp, static_cast<float>(data[i])});
};
auto linear_interp = [](float x, xy_float_t p1, xy_float_t p2) {
return (p2.y - p1.y) / (p2.x - p2.y) * (x - p1.x) + p1.y;
};
// Linear interpolation
uint8_t idx = static_cast<uint8_t>((temp - start_temp) / res_temp);
// offset in um
float offset = 0.0f;
#if !defined(PTC_LINEAR_EXTRAPOLATION) || PTC_LINEAR_EXTRAPOLATION <= 0
if (idx < 0)
offset = 0.0f;
else if (idx > measurements - 2)
offset = static_cast<float>(data[measurements - 1]);
#else
if (idx < 0)
offset = linear_interp(temp, point(0), point(PTC_LINEAR_EXTRAPOLATION));
else if (idx > measurements - 2)
offset = linear_interp(temp, point(measurements - PTC_LINEAR_EXTRAPOLATION - 1), point(measurements - 1));
#endif
else
offset = linear_interp(temp, point(idx), point(idx + 1));
// return offset in mm
return offset / 1000.0f;
}
bool ProbeTempComp::linear_regression(const TempSensorID tsi, float &k, float &d) {
if (tsi != TSI_PROBE && tsi != TSI_BED) return false;
if (!WITHIN(calib_idx, 2, cali_info[tsi].measurements)) return false;
const float start_temp = cali_info[tsi].start_temp,
res_temp = cali_info[tsi].temp_res;
const int16_t * const data = sensor_z_offsets[tsi];
float sum_x = start_temp,
sum_x2 = sq(start_temp),
sum_xy = 0, sum_y = 0;
LOOP_L_N(i, calib_idx) {
const float xi = start_temp + (i + 1) * res_temp,
yi = static_cast<float>(data[i]);
sum_x += xi;
sum_x2 += sq(xi);
sum_xy += xi * yi;
sum_y += yi;
}
const float denom = static_cast<float>(calib_idx + 1) * sum_x2 - sq(sum_x);
if (fabs(denom) <= 10e-5) {
// Singularity - unable to solve
k = d = 0.0;
return false;
}
k = (static_cast<float>(calib_idx + 1) * sum_xy - sum_x * sum_y) / denom;
d = (sum_y - k * sum_x) / static_cast<float>(calib_idx + 1);
return true;
}
#endif // PROBE_TEMP_COMPENSATION
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