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- /**
- * Marlin 3D Printer Firmware
- * Copyright (c) 2019 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 <http://www.gnu.org/licenses/>.
- *
- */
-
- #include "../inc/MarlinConfigPre.h"
-
- #if ENABLED(BACKLASH_COMPENSATION)
-
- #include "backlash.h"
-
- #include "../module/motion.h"
- #include "../module/planner.h"
-
- #ifdef BACKLASH_DISTANCE_MM
- #if ENABLED(BACKLASH_GCODE)
- xyz_float_t Backlash::distance_mm = BACKLASH_DISTANCE_MM;
- #else
- const xyz_float_t Backlash::distance_mm = BACKLASH_DISTANCE_MM;
- #endif
- #endif
-
- #if ENABLED(BACKLASH_GCODE)
- uint8_t Backlash::correction = (BACKLASH_CORRECTION) * 0xFF;
- #ifdef BACKLASH_SMOOTHING_MM
- float Backlash::smoothing_mm = BACKLASH_SMOOTHING_MM;
- #endif
- #endif
-
- #if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
- xyz_float_t Backlash::measured_mm{0};
- xyz_uint8_t Backlash::measured_count{0};
- #endif
-
- Backlash backlash;
-
- /**
- * To minimize seams in the printed part, backlash correction only adds
- * steps to the current segment (instead of creating a new segment, which
- * causes discontinuities and print artifacts).
- *
- * With a non-zero BACKLASH_SMOOTHING_MM value the backlash correction is
- * spread over multiple segments, smoothing out artifacts even more.
- */
-
- 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) {
- static uint8_t last_direction_bits;
- uint8_t changed_dir = last_direction_bits ^ dm;
- // Ignore direction change if no steps are taken in that direction
- if (da == 0) CBI(changed_dir, X_AXIS);
- if (db == 0) CBI(changed_dir, Y_AXIS);
- if (dc == 0) CBI(changed_dir, Z_AXIS);
- last_direction_bits ^= changed_dir;
-
- if (correction == 0) return;
-
- #ifdef BACKLASH_SMOOTHING_MM
- // The segment proportion is a value greater than 0.0 indicating how much residual_error
- // is corrected for in this segment. The contribution is based on segment length and the
- // smoothing distance. Since the computation of this proportion involves a floating point
- // division, defer computation until needed.
- float segment_proportion = 0;
-
- // Residual error carried forward across multiple segments, so correction can be applied
- // to segments where there is no direction change.
- static xyz_long_t residual_error{0};
- #else
- // No direction change, no correction.
- if (!changed_dir) return;
- // No leftover residual error from segment to segment
- xyz_long_t residual_error{0};
- #endif
-
- const float f_corr = float(correction) / 255.0f;
-
- LOOP_XYZ(axis) {
- if (distance_mm[axis]) {
- const bool reversing = TEST(dm,axis);
-
- // When an axis changes direction, add axis backlash to the residual error
- if (TEST(changed_dir, axis))
- residual_error[axis] += (reversing ? -f_corr : f_corr) * distance_mm[axis] * planner.settings.axis_steps_per_mm[axis];
-
- // Decide how much of the residual error to correct in this segment
- int32_t error_correction = residual_error[axis];
- #ifdef BACKLASH_SMOOTHING_MM
- if (error_correction && smoothing_mm != 0) {
- // Take up a portion of the residual_error in this segment, but only when
- // the current segment travels in the same direction as the correction
- if (reversing == (error_correction < 0)) {
- if (segment_proportion == 0)
- segment_proportion = _MIN(1.0f, block->millimeters / smoothing_mm);
- error_correction = CEIL(segment_proportion * error_correction);
- }
- else
- error_correction = 0; // Don't take up any backlash in this segment, as it would subtract steps
- }
- #endif
- // Making a correction reduces the residual error and modifies delta_mm
- if (error_correction) {
- block->steps[axis] += ABS(error_correction);
- residual_error[axis] -= error_correction;
- }
- }
- }
- }
-
- #if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
- #if HAS_CUSTOM_PROBE_PIN
- #define TEST_PROBE_PIN (READ(Z_MIN_PROBE_PIN) != Z_MIN_PROBE_ENDSTOP_INVERTING)
- #else
- #define TEST_PROBE_PIN (READ(Z_MIN_PIN) != Z_MIN_ENDSTOP_INVERTING)
- #endif
-
- // Measure Z backlash by raising nozzle in increments until probe deactivates
- void Backlash::measure_with_probe() {
- if (measured_count.z == 255) return;
-
- const float start_height = current_position.z;
- while (current_position.z < (start_height + BACKLASH_MEASUREMENT_LIMIT) && TEST_PROBE_PIN)
- do_blocking_move_to_z(current_position.z + BACKLASH_MEASUREMENT_RESOLUTION, MMM_TO_MMS(BACKLASH_MEASUREMENT_FEEDRATE));
-
- // The backlash from all probe points is averaged, so count the number of measurements
- measured_mm.z += current_position.z - start_height;
- measured_count.z++;
- }
- #endif
-
- #endif // BACKLASH_COMPENSATION
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