147 lines
5.4 KiB
C++
147 lines
5.4 KiB
C++
/**
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* Marlin 3D Printer Firmware
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* Copyright (C) 2019 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
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*
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* Based on Sprinter and grbl.
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* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "../inc/MarlinConfigPre.h"
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#if ENABLED(BACKLASH_COMPENSATION)
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#include "backlash.h"
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#include "../module/motion.h"
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#include "../module/planner.h"
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#ifdef BACKLASH_DISTANCE_MM
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#if ENABLED(BACKLASH_GCODE)
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float Backlash::distance_mm[XYZ] = BACKLASH_DISTANCE_MM;
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#else
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const float Backlash::distance_mm[XYZ] = BACKLASH_DISTANCE_MM;
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#endif
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#endif
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#if ENABLED(BACKLASH_GCODE)
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uint8_t Backlash::correction = (BACKLASH_CORRECTION) * 0xFF;
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#ifdef BACKLASH_SMOOTHING_MM
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float Backlash::smoothing_mm = BACKLASH_SMOOTHING_MM;
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#endif
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#endif
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#if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
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float Backlash::measured_mm[XYZ] = { 0 };
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uint8_t Backlash::measured_count[XYZ] = { 0 };
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#endif
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Backlash backlash;
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/**
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* To minimize seams in the printed part, backlash correction only adds
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* steps to the current segment (instead of creating a new segment, which
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* causes discontinuities and print artifacts).
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*
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* With a non-zero BACKLASH_SMOOTHING_MM value the backlash correction is
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* spread over multiple segments, smoothing out artifacts even more.
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*/
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void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const int32_t &dc, const uint8_t dm, block_t * const block) {
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static uint8_t last_direction_bits;
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uint8_t changed_dir = last_direction_bits ^ dm;
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// Ignore direction change if no steps are taken in that direction
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if (da == 0) CBI(changed_dir, X_AXIS);
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if (db == 0) CBI(changed_dir, Y_AXIS);
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if (dc == 0) CBI(changed_dir, Z_AXIS);
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last_direction_bits ^= changed_dir;
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if (correction == 0) return;
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#ifdef BACKLASH_SMOOTHING_MM
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// The segment proportion is a value greater than 0.0 indicating how much residual_error
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// is corrected for in this segment. The contribution is based on segment length and the
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// smoothing distance. Since the computation of this proportion involves a floating point
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// division, defer computation until needed.
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float segment_proportion = 0;
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// Residual error carried forward across multiple segments, so correction can be applied
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// to segments where there is no direction change.
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static int32_t residual_error[XYZ] = { 0 };
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#else
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// No direction change, no correction.
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if (!changed_dir) return;
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// No leftover residual error from segment to segment
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int32_t residual_error[XYZ] = { 0 };
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#endif
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const float f_corr = float(correction) / 255.0f;
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LOOP_XYZ(axis) {
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if (distance_mm[axis]) {
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const bool reversing = TEST(dm,axis);
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// When an axis changes direction, add axis backlash to the residual error
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if (TEST(changed_dir, axis))
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residual_error[axis] += (reversing ? -f_corr : f_corr) * distance_mm[axis] * planner.settings.axis_steps_per_mm[axis];
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// Decide how much of the residual error to correct in this segment
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int32_t error_correction = residual_error[axis];
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#ifdef BACKLASH_SMOOTHING_MM
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if (error_correction && smoothing_mm != 0) {
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// Take up a portion of the residual_error in this segment, but only when
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// the current segment travels in the same direction as the correction
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if (reversing == (error_correction < 0)) {
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if (segment_proportion == 0)
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segment_proportion = MIN(1.0f, block->millimeters / smoothing_mm);
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error_correction = CEIL(segment_proportion * error_correction);
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}
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else
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error_correction = 0; // Don't take up any backlash in this segment, as it would subtract steps
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}
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#endif
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// Making a correction reduces the residual error and modifies delta_mm
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if (error_correction) {
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block->steps[axis] += ABS(error_correction);
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residual_error[axis] -= error_correction;
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}
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}
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}
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}
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#if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
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#if USES_Z_MIN_PROBE_ENDSTOP
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#define TEST_PROBE_PIN (READ(Z_MIN_PROBE_PIN) != Z_MIN_PROBE_ENDSTOP_INVERTING)
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#else
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#define TEST_PROBE_PIN (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING)
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#endif
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// Measure Z backlash by raising nozzle in increments until probe deactivates
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void Backlash::measure_with_probe() {
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if (measured_count[Z_AXIS] == 255) return;
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float start_height = current_position[Z_AXIS];
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while (current_position[Z_AXIS] < (start_height + BACKLASH_MEASUREMENT_LIMIT) && TEST_PROBE_PIN)
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do_blocking_move_to_z(current_position[Z_AXIS] + BACKLASH_MEASUREMENT_RESOLUTION, MMM_TO_MMS(BACKLASH_MEASUREMENT_FEEDRATE));
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// The backlash from all probe points is averaged, so count the number of measurements
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measured_mm[Z_AXIS] += current_position[Z_AXIS] - start_height;
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measured_count[Z_AXIS]++;
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}
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#endif
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#endif // BACKLASH_COMPENSATION
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