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🐛 Fix steps-to-mm with backlash (#23814)

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Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>
This commit is contained in:
tombrazier 2022-02-26 20:30:33 +00:00 committed by Scott Lahteine
parent 8e11a2bb83
commit b0fdbede9c
3 changed files with 54 additions and 13 deletions
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31
Marlin/src/feature/backlash.cpp
View File

@ -29,6 +29,11 @@
#include "../module/motion.h"
#include "../module/planner.h"
axis_bits_t Backlash::last_direction_bits;
#ifdef BACKLASH_SMOOTHING_MM
xyz_long_t Backlash::residual_error{0};
#endif
#ifdef BACKLASH_DISTANCE_MM
#if ENABLED(BACKLASH_GCODE)
xyz_float_t Backlash::distance_mm = BACKLASH_DISTANCE_MM;
@ -61,7 +66,6 @@ Backlash backlash;
*/
void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const int32_t &dc, const axis_bits_t dm, block_t * const block) {
static axis_bits_t last_direction_bits;
axis_bits_t changed_dir = last_direction_bits ^ dm;
// Ignore direction change unless steps are taken in that direction
#if DISABLED(CORE_BACKLASH) || EITHER(MARKFORGED_XY, MARKFORGED_YX)
@ -91,10 +95,6 @@ void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const
// 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;
@ -153,6 +153,27 @@ void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const
}
}
int32_t Backlash::applied_steps(const AxisEnum axis) {
if (axis >= LINEAR_AXES) return 0;
const bool reversing = TEST(last_direction_bits, axis);
#ifdef BACKLASH_SMOOTHING_MM
const int32_t residual_error_axis = residual_error[axis];
#else
constexpr int32_t residual_error_axis = 0;
#endif
// At startup it is assumed the last move was forwards. So the applied
// steps will always be a non-positive number.
if (!reversing) return -residual_error_axis;
const float f_corr = float(correction) / 255.0f;
const int32_t full_error_axis = -f_corr * distance_mm[axis] * planner.settings.axis_steps_per_mm[axis];
return full_error_axis - residual_error_axis;
}
#if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
#include "../module/probe.h"

9
Marlin/src/feature/backlash.h
View File

@ -27,6 +27,12 @@
constexpr uint8_t all_on = 0xFF, all_off = 0x00;
class Backlash {
private:
static axis_bits_t last_direction_bits;
#ifdef BACKLASH_SMOOTHING_MM
static xyz_long_t residual_error;
#endif
public:
#if ENABLED(BACKLASH_GCODE)
static xyz_float_t distance_mm;
@ -71,7 +77,8 @@ public:
return has_measurement(X_AXIS) || has_measurement(Y_AXIS) || has_measurement(Z_AXIS);
}
void add_correction_steps(const int32_t &da, const int32_t &db, const int32_t &dc, const axis_bits_t dm, block_t * const block);
static void add_correction_steps(const int32_t &da, const int32_t &db, const int32_t &dc, const axis_bits_t dm, block_t * const block);
static int32_t applied_steps(const AxisEnum axis);
};
extern Backlash backlash;

27
Marlin/src/module/planner.cpp
View File

@ -1706,7 +1706,8 @@ void Planner::endstop_triggered(const AxisEnum axis) {
}
float Planner::triggered_position_mm(const AxisEnum axis) {
return stepper.triggered_position(axis) * mm_per_step[axis];
const float result = DIFF_TERN(BACKLASH_COMPENSATION, stepper.triggered_position(axis), backlash.applied_steps(axis));
return result * mm_per_step[axis];
}
void Planner::finish_and_disable() {
@ -1728,8 +1729,8 @@ float Planner::get_axis_position_mm(const AxisEnum axis) {
// Protect the access to the position.
const bool was_enabled = stepper.suspend();
const int32_t p1 = stepper.position(CORE_AXIS_1),
p2 = stepper.position(CORE_AXIS_2);
const int32_t p1 = DIFF_TERN(BACKLASH_COMPENSATION, stepper.position(CORE_AXIS_1), backlash.applied_steps(CORE_AXIS_1)),
p2 = DIFF_TERN(BACKLASH_COMPENSATION, stepper.position(CORE_AXIS_2), backlash.applied_steps(CORE_AXIS_2));
if (was_enabled) stepper.wake_up();
@ -1738,7 +1739,7 @@ float Planner::get_axis_position_mm(const AxisEnum axis) {
axis_steps = (axis == CORE_AXIS_2 ? CORESIGN(p1 - p2) : p1 + p2) * 0.5f;
}
else
axis_steps = stepper.position(axis);
axis_steps = DIFF_TERN(BACKLASH_COMPENSATION, stepper.position(axis), backlash.applied_steps(axis));
#elif EITHER(MARKFORGED_XY, MARKFORGED_YX)
@ -1755,11 +1756,12 @@ float Planner::get_axis_position_mm(const AxisEnum axis) {
axis_steps = ((axis == CORE_AXIS_1) ? p1 - p2 : p2);
}
else
axis_steps = stepper.position(axis);
axis_steps = DIFF_TERN(BACKLASH_COMPENSATION, stepper.position(axis), backlash.applied_steps(axis));
#else
axis_steps = stepper.position(axis);
TERN_(BACKLASH_COMPENSATION, axis_steps -= backlash.applied_steps(axis));
#endif
@ -2841,6 +2843,9 @@ void Planner::buffer_sync_block(TERN_(LASER_SYNCHRONOUS_M106_M107, uint8_t sync_
block->flag = sync_flag;
block->position = position;
#if ENABLED(BACKLASH_COMPENSATION)
LOOP_LINEAR_AXES(axis) block->position[axis] += backlash.applied_steps((AxisEnum)axis);
#endif
#if BOTH(HAS_FAN, LASER_SYNCHRONOUS_M106_M107)
FANS_LOOP(i) block->fan_speed[i] = thermalManager.fan_speed[i];
@ -3108,13 +3113,21 @@ void Planner::set_machine_position_mm(const abce_pos_t &abce) {
LROUND(abce.k * settings.axis_steps_per_mm[K_AXIS])
)
);
if (has_blocks_queued()) {
//previous_nominal_speed_sqr = 0.0; // Reset planner junction speeds. Assume start from rest.
//previous_speed.reset();
buffer_sync_block();
}
else
stepper.set_position(position);
else {
#if ENABLED(BACKLASH_COMPENSATION)
abce_long_t stepper_pos = position;
LOOP_LINEAR_AXES(axis) stepper_pos[axis] += backlash.applied_steps((AxisEnum)axis);
stepper.set_position(stepper_pos);
#else
stepper.set_position(position);
#endif
}
}
void Planner::set_position_mm(const xyze_pos_t &xyze) {