Adding to #23814: correct backlash applied steps when config changes

Marlin/src/feature/backlash.cpp

@@ -30,9 +30,7 @@
 #include "../module/planner.h"
 
 axis_bits_t Backlash::last_direction_bits;
-#ifdef BACKLASH_SMOOTHING_MM
-  xyz_long_t Backlash::residual_error{0};
-#endif
+xyz_long_t Backlash::residual_error{0};
 
 #ifdef BACKLASH_DISTANCE_MM
   #if ENABLED(BACKLASH_GCODE)
@@ -43,7 +41,7 @@ axis_bits_t Backlash::last_direction_bits;
 #endif
 
 #if ENABLED(BACKLASH_GCODE)
-  uint8_t Backlash::correction = (BACKLASH_CORRECTION) * 0xFF;
+  uint8_t Backlash::correction = (BACKLASH_CORRECTION) * all_on;
   #ifdef BACKLASH_SMOOTHING_MM
     float Backlash::smoothing_mm = BACKLASH_SMOOTHING_MM;
   #endif
@@ -87,22 +85,20 @@ void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const
   #endif
   last_direction_bits ^= changed_dir;
 
-  if (correction == 0) return;
+  bool nothing_to_do = !correction;
+  for (uint8_t axis = 0; nothing_to_do && axis < LINEAR_AXES; axis++)
+    nothing_to_do = !residual_error[axis];
+  if (nothing_to_do) 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;
-  #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;
+  const float f_corr = float(correction) / all_on;
 
   LOOP_LINEAR_AXES(axis) {
     if (distance_mm[axis]) {
@@ -114,16 +110,14 @@ void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const
 
       // Decide how much of the residual error to correct in this segment
       int32_t error_correction = residual_error[axis];
+      if (reversing != (error_correction < 0))
+        error_correction = 0; // Don't take up any backlash in this segment, as it would subtract steps
+
       #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
+          // Take up a portion of the residual_error in this segment
+          if (segment_proportion == 0) segment_proportion = _MIN(1.0f, block->millimeters / smoothing_mm);
+          error_correction = CEIL(segment_proportion * error_correction);
         }
       #endif
 
@@ -153,27 +147,52 @@ void Backlash::add_correction_steps(const int32_t &da, const int32_t &db, const
   }
 }
 
-int32_t Backlash::applied_steps(const AxisEnum axis) {
+int32_t Backlash::get_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
+  const int32_t residual_error_axis = residual_error[axis];
 
   // 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 float f_corr = float(correction) / all_on;
   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;
 }
 
+class Backlash::StepAdjuster {
+  xyz_long_t applied_steps;
+public:
+  StepAdjuster() {
+    LOOP_LINEAR_AXES(axis) applied_steps[axis] = backlash.get_applied_steps((AxisEnum)axis);
+  }
+  ~StepAdjuster() {
+    // after backlash compensation parameter changes, ensure applied step count does not change
+    LOOP_LINEAR_AXES(axis) residual_error[axis] += backlash.get_applied_steps((AxisEnum)axis) - applied_steps[axis];
+  }
+};
+
+void Backlash::set_correction_uint8(const uint8_t v) {
+  StepAdjuster adjuster;
+  correction = v;
+}
+
+void Backlash::set_distance_mm(const AxisEnum axis, const float v) {
+  StepAdjuster adjuster;
+  distance_mm[axis] = v;
+}
+
+#ifdef BACKLASH_SMOOTHING_MM
+  void Backlash::set_smoothing_mm(const float v) {
+    StepAdjuster adjuster;
+    smoothing_mm = v;
+  }
+#endif
+
 #if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
 
   #include "../module/probe.h"

Marlin/src/feature/backlash.h

@@ -24,41 +24,36 @@
 #include "../inc/MarlinConfigPre.h"
 #include "../module/planner.h"
 
-constexpr uint8_t all_on = 0xFF, all_off = 0x00;
-
 class Backlash {
+public:
+  static constexpr uint8_t all_on = 0xFF, all_off = 0x00;
+
 private:
   static axis_bits_t last_direction_bits;
-  #ifdef BACKLASH_SMOOTHING_MM
-    static xyz_long_t residual_error;
-  #endif
+  static xyz_long_t residual_error;
 
-public:
   #if ENABLED(BACKLASH_GCODE)
-    static xyz_float_t distance_mm;
     static uint8_t correction;
+    static xyz_float_t distance_mm;
     #ifdef BACKLASH_SMOOTHING_MM
       static float smoothing_mm;
     #endif
-
-    static void set_correction(const_float_t v) { correction = _MAX(0, _MIN(1.0, v)) * all_on; }
-    static float get_correction() { return float(ui8_to_percent(correction)) / 100.0f; }
   #else
-    static constexpr uint8_t correction = (BACKLASH_CORRECTION) * 0xFF;
+    static constexpr uint8_t correction = (BACKLASH_CORRECTION) * all_on;
     static const xyz_float_t distance_mm;
     #ifdef BACKLASH_SMOOTHING_MM
       static constexpr float smoothing_mm = BACKLASH_SMOOTHING_MM;
     #endif
   #endif
 
   #if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
-    private:
-      static xyz_float_t measured_mm;
-      static xyz_uint8_t measured_count;
-    public:
-      static void measure_with_probe();
+    static xyz_float_t measured_mm;
+    static xyz_uint8_t measured_count;
   #endif
 
+  class StepAdjuster;
+
+public:
   static float get_measurement(const AxisEnum a) {
     UNUSED(a);
     // Return the measurement averaged over all readings
@@ -78,7 +73,24 @@ class Backlash {
   }
 
   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);
+  static int32_t get_applied_steps(const AxisEnum axis);
+
+  #if ENABLED(BACKLASH_GCODE)
+    static void set_correction_uint8(const uint8_t v);
+    static uint8_t get_correction_uint8() { return correction; }
+    static void set_correction(const float v) { set_correction_uint8(_MAX(0, _MIN(1.0, v)) * all_on + 0.5f); }
+    static float get_correction() { return float(get_correction_uint8()) / all_on; }
+    static void set_distance_mm(const AxisEnum axis, const float v);
+    static float get_distance_mm(const AxisEnum axis) {return distance_mm[axis];}
+    #ifdef BACKLASH_SMOOTHING_MM
+      static void set_smoothing_mm(const float v);
+      static float get_smoothing_mm() {return smoothing_mm;}
+    #endif
+  #endif
+
+  #if ENABLED(MEASURE_BACKLASH_WHEN_PROBING)
+    static void measure_with_probe();
+  #endif
 };
 
 extern Backlash backlash;

Marlin/src/gcode/calibrate/G425.cpp

@@ -105,13 +105,27 @@ struct measurements_t {
 };
 
 #if ENABLED(BACKLASH_GCODE)
-  #define TEMPORARY_BACKLASH_CORRECTION(value) REMEMBER(tbst, backlash.correction, value)
+  class restorer_correction {
+    const uint8_t val_;
+  public:
+    restorer_correction(const uint8_t temp_val) : val_(backlash.get_correction_uint8()) { backlash.set_correction_uint8(temp_val); }
+    ~restorer_correction() { backlash.set_correction_uint8(val_); }
+  };
+
+  #define TEMPORARY_BACKLASH_CORRECTION(value) restorer_correction restorer_tbst(value)
 #else
   #define TEMPORARY_BACKLASH_CORRECTION(value)
 #endif
 
 #if ENABLED(BACKLASH_GCODE) && defined(BACKLASH_SMOOTHING_MM)
-  #define TEMPORARY_BACKLASH_SMOOTHING(value) REMEMBER(tbsm, backlash.smoothing_mm, value)
+  class restorer_smoothing {
+    const float val_;
+  public:
+    restorer_smoothing(const float temp_val) : val_(backlash.get_smoothing_mm()) { backlash.set_smoothing_mm(temp_val); }
+    ~restorer_smoothing() { backlash.set_smoothing_mm(val_); }
+  };
+
+  #define TEMPORARY_BACKLASH_SMOOTHING(value) restorer_smoothing restorer_tbsm(value)
 #else
   #define TEMPORARY_BACKLASH_SMOOTHING(value)
 #endif
@@ -524,53 +538,53 @@ inline void calibrate_backlash(measurements_t &m, const float uncertainty) {
 
   {
     // New scope for TEMPORARY_BACKLASH_CORRECTION
-    TEMPORARY_BACKLASH_CORRECTION(all_off);
+    TEMPORARY_BACKLASH_CORRECTION(backlash.all_off);
     TEMPORARY_BACKLASH_SMOOTHING(0.0f);
 
     probe_sides(m, uncertainty);
 
     #if ENABLED(BACKLASH_GCODE)
 
       #if HAS_X_CENTER
-        backlash.distance_mm.x = (m.backlash[LEFT] + m.backlash[RIGHT]) / 2;
+        backlash.set_distance_mm(X_AXIS, (m.backlash[LEFT] + m.backlash[RIGHT]) / 2);
       #elif ENABLED(CALIBRATION_MEASURE_LEFT)
-        backlash.distance_mm.x = m.backlash[LEFT];
+        backlash.set_distance_mm(X_AXIS, m.backlash[LEFT]);
       #elif ENABLED(CALIBRATION_MEASURE_RIGHT)
-        backlash.distance_mm.x = m.backlash[RIGHT];
+        backlash.set_distance_mm(X_AXIS, m.backlash[RIGHT]);
       #endif
 
       #if HAS_Y_CENTER
-        backlash.distance_mm.y = (m.backlash[FRONT] + m.backlash[BACK]) / 2;
+        backlash.set_distance_mm(Y_AXIS, (m.backlash[FRONT] + m.backlash[BACK]) / 2);
       #elif ENABLED(CALIBRATION_MEASURE_FRONT)
-        backlash.distance_mm.y = m.backlash[FRONT];
+        backlash.set_distance_mm(Y_AXIS, m.backlash[FRONT]);
       #elif ENABLED(CALIBRATION_MEASURE_BACK)
-        backlash.distance_mm.y = m.backlash[BACK];
+        backlash.set_distance_mm(Y_AXIS, m.backlash[BACK]);
       #endif
 
-      TERN_(HAS_Z_AXIS, if (AXIS_CAN_CALIBRATE(Z)) backlash.distance_mm.z = m.backlash[TOP]);
+      TERN_(HAS_Z_AXIS, if (AXIS_CAN_CALIBRATE(Z)) backlash.set_distance_mm(Z_AXIS, m.backlash[TOP]));
 
       #if HAS_I_CENTER
-        backlash.distance_mm.i = (m.backlash[IMINIMUM] + m.backlash[IMAXIMUM]) / 2;
+        backlash.set_distance_mm(I_AXIS, (m.backlash[IMINIMUM] + m.backlash[IMAXIMUM]) / 2);
       #elif ENABLED(CALIBRATION_MEASURE_IMIN)
-        backlash.distance_mm.i = m.backlash[IMINIMUM];
+        backlash.set_distance_mm(I_AXIS, m.backlash[IMINIMUM]);
       #elif ENABLED(CALIBRATION_MEASURE_IMAX)
-        backlash.distance_mm.i = m.backlash[IMAXIMUM];
+        backlash.set_distance_mm(I_AXIS, m.backlash[IMAXIMUM]);
       #endif
 
       #if HAS_J_CENTER
-        backlash.distance_mm.j = (m.backlash[JMINIMUM] + m.backlash[JMAXIMUM]) / 2;
+        backlash.set_distance_mm(J_AXIS, (m.backlash[JMINIMUM] + m.backlash[JMAXIMUM]) / 2);
       #elif ENABLED(CALIBRATION_MEASURE_JMIN)
-        backlash.distance_mm.j = m.backlash[JMINIMUM];
+        backlash.set_distance_mm(J_AXIS, m.backlash[JMINIMUM]);
       #elif ENABLED(CALIBRATION_MEASURE_JMAX)
-        backlash.distance_mm.j = m.backlash[JMAXIMUM];
+        backlash.set_distance_mm(J_AXIS, m.backlash[JMAXIMUM]);
       #endif
 
       #if HAS_K_CENTER
-        backlash.distance_mm.k = (m.backlash[KMINIMUM] + m.backlash[KMAXIMUM]) / 2;
+        backlash.set_distance_mm(K_AXIS, (m.backlash[KMINIMUM] + m.backlash[KMAXIMUM]) / 2);
       #elif ENABLED(CALIBRATION_MEASURE_KMIN)
-        backlash.distance_mm.k = m.backlash[KMINIMUM];
+        backlash.set_distance_mm(K_AXIS, m.backlash[KMINIMUM]);
       #elif ENABLED(CALIBRATION_MEASURE_KMAX)
-        backlash.distance_mm.k = m.backlash[KMAXIMUM];
+        backlash.set_distance_mm(K_AXIS, m.backlash[KMAXIMUM]);
       #endif
 
     #endif // BACKLASH_GCODE
@@ -581,7 +595,7 @@ inline void calibrate_backlash(measurements_t &m, const float uncertainty) {
     // allowed directions to take up any backlash
     {
       // New scope for TEMPORARY_BACKLASH_CORRECTION
-      TEMPORARY_BACKLASH_CORRECTION(all_on);
+      TEMPORARY_BACKLASH_CORRECTION(backlash.all_on);
       TEMPORARY_BACKLASH_SMOOTHING(0.0f);
       const xyz_float_t move = LINEAR_AXIS_ARRAY(
         AXIS_CAN_CALIBRATE(X) * 3, AXIS_CAN_CALIBRATE(Y) * 3, AXIS_CAN_CALIBRATE(Z) * 3,
@@ -611,7 +625,7 @@ inline void update_measurements(measurements_t &m, const AxisEnum axis) {
  *    - Call calibrate_backlash() beforehand for best accuracy
  */
 inline void calibrate_toolhead(measurements_t &m, const float uncertainty, const uint8_t extruder) {
-  TEMPORARY_BACKLASH_CORRECTION(all_on);
+  TEMPORARY_BACKLASH_CORRECTION(backlash.all_on);
   TEMPORARY_BACKLASH_SMOOTHING(0.0f);
 
   TERN(HAS_MULTI_HOTEND, set_nozzle(m, extruder), UNUSED(extruder));
@@ -648,7 +662,7 @@ inline void calibrate_toolhead(measurements_t &m, const float uncertainty, const
  *   uncertainty    in     - How far away from the object to begin probing
  */
 inline void calibrate_all_toolheads(measurements_t &m, const float uncertainty) {
-  TEMPORARY_BACKLASH_CORRECTION(all_on);
+  TEMPORARY_BACKLASH_CORRECTION(backlash.all_on);
   TEMPORARY_BACKLASH_SMOOTHING(0.0f);
 
   HOTEND_LOOP() calibrate_toolhead(m, uncertainty, e);
@@ -674,7 +688,7 @@ inline void calibrate_all() {
 
   TERN_(HAS_HOTEND_OFFSET, reset_hotend_offsets());
 
-  TEMPORARY_BACKLASH_CORRECTION(all_on);
+  TEMPORARY_BACKLASH_CORRECTION(backlash.all_on);
   TEMPORARY_BACKLASH_SMOOTHING(0.0f);
 
   // Do a fast and rough calibration of the toolheads