diff --git a/Marlin/planner.cpp b/Marlin/planner.cpp
index 14303804a62e433713a89c381b03e5ea8e05e38e..b4b0ef9f371752554a54b198ac60644719b17c14 100644
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@@ -85,8 +85,8 @@ float Planner::max_feedrate_mm_s[NUM_AXIS], // Max speeds in mm per second
Planner::axis_steps_per_mm[NUM_AXIS],
Planner::steps_to_mm[NUM_AXIS];
-unsigned long Planner::max_acceleration_steps_per_s2[NUM_AXIS],
- Planner::max_acceleration_mm_per_s2[NUM_AXIS]; // Use M201 to override by software
+uint32_t Planner::max_acceleration_steps_per_s2[NUM_AXIS],
+ Planner::max_acceleration_mm_per_s2[NUM_AXIS]; // Use M201 to override by software
millis_t Planner::min_segment_time;
float Planner::min_feedrate_mm_s,
@@ -236,6 +236,7 @@ void Planner::reverse_pass() {
uint8_t b = BLOCK_MOD(block_buffer_head - 3);
while (b != tail) {
+ if (block[0] && (block[0]->flag & BLOCK_FLAG_START_FROM_FULL_HALT)) break;
b = prev_block_index(b);
block[2] = block[1];
block[1] = block[0];
@@ -696,6 +697,9 @@ void Planner::_buffer_line(const float &a, const float &b, const float &c, const
// Bail if this is a zero-length block
if (block->step_event_count < MIN_STEPS_PER_SEGMENT) return;
+ // Clear the block flags
+ block->flag = 0;
+
// For a mixing extruder, get a magnified step_event_count for each
#if ENABLED(MIXING_EXTRUDER)
for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
@@ -1011,90 +1015,170 @@ void Planner::_buffer_line(const float &a, const float &b, const float &c, const
// Compute and limit the acceleration rate for the trapezoid generator.
float steps_per_mm = block->step_event_count / block->millimeters;
+ uint32_t accel;
if (!block->steps[X_AXIS] && !block->steps[Y_AXIS] && !block->steps[Z_AXIS]) {
- block->acceleration_steps_per_s2 = ceil(retract_acceleration * steps_per_mm); // convert to: acceleration steps/sec^2
+ // convert to: acceleration steps/sec^2
+ accel = ceil(retract_acceleration * steps_per_mm);
}
else {
+ #define LIMIT_ACCEL(AXIS) do{ \
+ const uint32_t comp = max_acceleration_steps_per_s2[AXIS] * block->step_event_count; \
+ if (accel * block->steps[AXIS] > comp) accel = comp / block->steps[AXIS]; \
+ }while(0)
+
+ // Start with print or travel acceleration
+ accel = ceil((block->steps[E_AXIS] ? acceleration : travel_acceleration) * steps_per_mm);
+
// Limit acceleration per axis
- block->acceleration_steps_per_s2 = ceil((block->steps[E_AXIS] ? acceleration : travel_acceleration) * steps_per_mm);
- if (max_acceleration_steps_per_s2[X_AXIS] < (block->acceleration_steps_per_s2 * block->steps[X_AXIS]) / block->step_event_count)
- block->acceleration_steps_per_s2 = (max_acceleration_steps_per_s2[X_AXIS] * block->step_event_count) / block->steps[X_AXIS];
- if (max_acceleration_steps_per_s2[Y_AXIS] < (block->acceleration_steps_per_s2 * block->steps[Y_AXIS]) / block->step_event_count)
- block->acceleration_steps_per_s2 = (max_acceleration_steps_per_s2[Y_AXIS] * block->step_event_count) / block->steps[Y_AXIS];
- if (max_acceleration_steps_per_s2[Z_AXIS] < (block->acceleration_steps_per_s2 * block->steps[Z_AXIS]) / block->step_event_count)
- block->acceleration_steps_per_s2 = (max_acceleration_steps_per_s2[Z_AXIS] * block->step_event_count) / block->steps[Z_AXIS];
- if (max_acceleration_steps_per_s2[E_AXIS] < (block->acceleration_steps_per_s2 * block->steps[E_AXIS]) / block->step_event_count)
- block->acceleration_steps_per_s2 = (max_acceleration_steps_per_s2[E_AXIS] * block->step_event_count) / block->steps[E_AXIS];
+ LIMIT_ACCEL(X_AXIS);
+ LIMIT_ACCEL(Y_AXIS);
+ LIMIT_ACCEL(Z_AXIS);
+ LIMIT_ACCEL(E_AXIS);
}
- block->acceleration = block->acceleration_steps_per_s2 / steps_per_mm;
- block->acceleration_rate = (long)(block->acceleration_steps_per_s2 * 16777216.0 / ((F_CPU) * 0.125));
+ block->acceleration_steps_per_s2 = accel;
+ block->acceleration = accel / steps_per_mm;
+ block->acceleration_rate = (long)(accel * 16777216.0 / ((F_CPU) * 0.125)); // * 8.388608
+
+ // Initial limit on the segment entry velocity
+ float vmax_junction;
#if 0 // Use old jerk for now
float junction_deviation = 0.1;
// Compute path unit vector
- double unit_vec[XYZ];
-
- unit_vec[X_AXIS] = delta_mm[X_AXIS] * inverse_millimeters;
- unit_vec[Y_AXIS] = delta_mm[Y_AXIS] * inverse_millimeters;
- unit_vec[Z_AXIS] = delta_mm[Z_AXIS] * inverse_millimeters;
-
- // Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
- // Let a circle be tangent to both previous and current path line segments, where the junction
- // deviation is defined as the distance from the junction to the closest edge of the circle,
- // collinear with the circle center. The circular segment joining the two paths represents the
- // path of centripetal acceleration. Solve for max velocity based on max acceleration about the
- // radius of the circle, defined indirectly by junction deviation. This may be also viewed as
- // path width or max_jerk in the previous grbl version. This approach does not actually deviate
- // from path, but used as a robust way to compute cornering speeds, as it takes into account the
- // nonlinearities of both the junction angle and junction velocity.
- double vmax_junction = MINIMUM_PLANNER_SPEED; // Set default max junction speed
+ double unit_vec[XYZ] = {
+ delta_mm[X_AXIS] * inverse_millimeters,
+ delta_mm[Y_AXIS] * inverse_millimeters,
+ delta_mm[Z_AXIS] * inverse_millimeters
+ };
+
+ /*
+ Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
+
+ Let a circle be tangent to both previous and current path line segments, where the junction
+ deviation is defined as the distance from the junction to the closest edge of the circle,
+ collinear with the circle center.
+
+ The circular segment joining the two paths represents the path of centripetal acceleration.
+ Solve for max velocity based on max acceleration about the radius of the circle, defined
+ indirectly by junction deviation.
+
+ This may be also viewed as path width or max_jerk in the previous grbl version. This approach
+ does not actually deviate from path, but used as a robust way to compute cornering speeds, as
+ it takes into account the nonlinearities of both the junction angle and junction velocity.
+ */
+
+ vmax_junction = MINIMUM_PLANNER_SPEED; // Set default max junction speed
// Skip first block or when previous_nominal_speed is used as a flag for homing and offset cycles.
- if ((block_buffer_head != block_buffer_tail) && (previous_nominal_speed > 0.0)) {
+ if (block_buffer_head != block_buffer_tail && previous_nominal_speed > 0.0) {
// Compute cosine of angle between previous and current path. (prev_unit_vec is negative)
// NOTE: Max junction velocity is computed without sin() or acos() by trig half angle identity.
- double cos_theta = - previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
- - previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
- - previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ;
+ float cos_theta = - previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
+ - previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
+ - previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ;
// Skip and use default max junction speed for 0 degree acute junction.
if (cos_theta < 0.95) {
vmax_junction = min(previous_nominal_speed, block->nominal_speed);
// Skip and avoid divide by zero for straight junctions at 180 degrees. Limit to min() of nominal speeds.
if (cos_theta > -0.95) {
// Compute maximum junction velocity based on maximum acceleration and junction deviation
- double sin_theta_d2 = sqrt(0.5 * (1.0 - cos_theta)); // Trig half angle identity. Always positive.
+ float sin_theta_d2 = sqrt(0.5 * (1.0 - cos_theta)); // Trig half angle identity. Always positive.
NOMORE(vmax_junction, sqrt(block->acceleration * junction_deviation * sin_theta_d2 / (1.0 - sin_theta_d2)));
}
}
}
#endif
- // Start with a safe speed
- float vmax_junction = max_jerk[X_AXIS] * 0.5, vmax_junction_factor = 1.0;
- if (max_jerk[Y_AXIS] * 0.5 < fabs(current_speed[Y_AXIS])) NOMORE(vmax_junction, max_jerk[Y_AXIS] * 0.5);
- if (max_jerk[Z_AXIS] * 0.5 < fabs(current_speed[Z_AXIS])) NOMORE(vmax_junction, max_jerk[Z_AXIS] * 0.5);
- if (max_jerk[E_AXIS] * 0.5 < fabs(current_speed[E_AXIS])) NOMORE(vmax_junction, max_jerk[E_AXIS] * 0.5);
- NOMORE(vmax_junction, block->nominal_speed);
- float safe_speed = vmax_junction;
+ /**
+ * Adapted from Prusa MKS firmware
+ *
+ * Start with a safe speed (from which the machine may halt to stop immediately).
+ */
+
+ // Exit speed limited by a jerk to full halt of a previous last segment
+ static float previous_safe_speed;
+
+ float safe_speed = block->nominal_speed;
+ bool limited = false;
+ LOOP_XYZE(i) {
+ float jerk = fabs(current_speed[i]);
+ if (jerk > max_jerk[i]) {
+ // The actual jerk is lower if it has been limited by the XY jerk.
+ if (limited) {
+ // Spare one division by a following gymnastics:
+ // Instead of jerk *= safe_speed / block->nominal_speed,
+ // multiply max_jerk[i] by the divisor.
+ jerk *= safe_speed;
+ float mjerk = max_jerk[i] * block->nominal_speed;
+ if (jerk > mjerk) safe_speed *= mjerk / jerk;
+ }
+ else {
+ safe_speed = max_jerk[i];
+ limited = true;
+ }
+ }
+ }
if (moves_queued > 1 && previous_nominal_speed > 0.0001) {
- //if ((fabs(previous_speed[X_AXIS]) > 0.0001) || (fabs(previous_speed[Y_AXIS]) > 0.0001)) {
- vmax_junction = block->nominal_speed;
- //}
-
- float dsx = fabs(current_speed[X_AXIS] - previous_speed[X_AXIS]),
- dsy = fabs(current_speed[Y_AXIS] - previous_speed[Y_AXIS]),
- dsz = fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]),
- dse = fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]);
- if (dsx > max_jerk[X_AXIS]) NOMORE(vmax_junction_factor, max_jerk[X_AXIS] / dsx);
- if (dsy > max_jerk[Y_AXIS]) NOMORE(vmax_junction_factor, max_jerk[Y_AXIS] / dsy);
- if (dsz > max_jerk[Z_AXIS]) NOMORE(vmax_junction_factor, max_jerk[Z_AXIS] / dsz);
- if (dse > max_jerk[E_AXIS]) NOMORE(vmax_junction_factor, max_jerk[E_AXIS] / dse);
-
- vmax_junction = min(previous_nominal_speed, vmax_junction * vmax_junction_factor); // Limit speed to max previous speed
+ // Estimate a maximum velocity allowed at a joint of two successive segments.
+ // If this maximum velocity allowed is lower than the minimum of the entry / exit safe velocities,
+ // then the machine is not coasting anymore and the safe entry / exit velocities shall be used.
+
+ // The junction velocity will be shared between successive segments. Limit the junction velocity to their minimum.
+ bool prev_speed_larger = previous_nominal_speed > block->nominal_speed;
+ float smaller_speed_factor = prev_speed_larger ? (block->nominal_speed / previous_nominal_speed) : (previous_nominal_speed / block->nominal_speed);
+ // Pick the smaller of the nominal speeds. Higher speed shall not be achieved at the junction during coasting.
+ vmax_junction = prev_speed_larger ? block->nominal_speed : previous_nominal_speed;
+ // Factor to multiply the previous / current nominal velocities to get componentwise limited velocities.
+ float v_factor = 1.f;
+ limited = false;
+ // Now limit the jerk in all axes.
+ LOOP_XYZE(axis) {
+ // Limit an axis. We have to differentiate: coasting, reversal of an axis, full stop.
+ float v_exit = previous_speed[axis], v_entry = current_speed[axis];
+ if (prev_speed_larger) v_exit *= smaller_speed_factor;
+ if (limited) {
+ v_exit *= v_factor;
+ v_entry *= v_factor;
+ }
+ // Calculate jerk depending on whether the axis is coasting in the same direction or reversing.
+ float jerk =
+ (v_exit > v_entry) ?
+ ((v_entry > 0.f || v_exit < 0.f) ?
+ // coasting
+ (v_exit - v_entry) :
+ // axis reversal
+ max(v_exit, -v_entry)) :
+ // v_exit <= v_entry
+ ((v_entry < 0.f || v_exit > 0.f) ?
+ // coasting
+ (v_entry - v_exit) :
+ // axis reversal
+ max(-v_exit, v_entry));
+ if (jerk > max_jerk[axis]) {
+ v_factor *= max_jerk[axis] / jerk;
+ limited = true;
+ }
+ }
+ if (limited) vmax_junction *= v_factor;
+ // Now the transition velocity is known, which maximizes the shared exit / entry velocity while
+ // respecting the jerk factors, it may be possible, that applying separate safe exit / entry velocities will achieve faster prints.
+ float vmax_junction_threshold = vmax_junction * 0.99f;
+ if (previous_safe_speed > vmax_junction_threshold && safe_speed > vmax_junction_threshold) {
+ // Not coasting. The machine will stop and start the movements anyway,
+ // better to start the segment from start.
+ block->flag |= BLOCK_FLAG_START_FROM_FULL_HALT;
+ vmax_junction = safe_speed;
+ }
}
+ else {
+ block->flag |= BLOCK_FLAG_START_FROM_FULL_HALT;
+ vmax_junction = safe_speed;
+ }
+
+ // Max entry speed of this block equals the max exit speed of the previous block.
block->max_entry_speed = vmax_junction;
// Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED.
@@ -1109,13 +1193,12 @@ void Planner::_buffer_line(const float &a, const float &b, const float &c, const
// block nominal speed limits both the current and next maximum junction speeds. Hence, in both
// the reverse and forward planners, the corresponding block junction speed will always be at the
// the maximum junction speed and may always be ignored for any speed reduction checks.
- block->flag &= ~BLOCK_FLAG_NOMINAL_LENGTH;
- if (block->nominal_speed <= v_allowable) block->flag |= BLOCK_FLAG_NOMINAL_LENGTH;
- block->flag |= BLOCK_FLAG_RECALCULATE; // Always calculate trapezoid for new block
+ block->flag |= BLOCK_FLAG_RECALCULATE | (block->nominal_speed <= v_allowable ? BLOCK_FLAG_NOMINAL_LENGTH : 0);
// Update previous path unit_vector and nominal speed
memcpy(previous_speed, current_speed, sizeof(previous_speed));
previous_nominal_speed = block->nominal_speed;
+ previous_safe_speed = safe_speed;
#if ENABLED(LIN_ADVANCE)