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Fix/Improve junction deviation

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- Respect axis max acceleration limits instead of forcing a fixed acceleration value.
- The `junction_unit_vec` ensures proper handling of entry and exit speeds even when the axes involved have different limits.
This commit is contained in:
Sebastianv650
2018-05-31 08:35:54 +02:00
committed by Scott Lahteine
parent c010b1f43f
commit 568b19e7d4
4 changed files with 43 additions and 7 deletions
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21
Marlin/planner.cpp
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@@ -2148,11 +2148,22 @@ bool Planner::_populate_block(block_t * const block, bool split_move,
}
else {
NOLESS(junction_cos_theta, -0.999999); // Check for numerical round-off to avoid divide by zero.
const float sin_theta_d2 = SQRT(0.5 * (1.0 - junction_cos_theta)); // Trig half angle identity. Always positive.
// TODO: Technically, the acceleration used in calculation needs to be limited by the minimum of the
// two junctions. However, this shouldn't be a significant problem except in extreme circumstances.
vmax_junction_sqr = (JUNCTION_ACCELERATION * JUNCTION_DEVIATION_MM * sin_theta_d2) / (1.0 - sin_theta_d2);
float junction_unit_vec[JD_AXES] = {
unit_vec[X_AXIS] - previous_unit_vec[X_AXIS],
unit_vec[Y_AXIS] - previous_unit_vec[Y_AXIS],
unit_vec[Z_AXIS] - previous_unit_vec[Z_AXIS]
#if ENABLED(JUNCTION_DEVIATION_INCLUDE_E)
, unit_vec[E_AXIS] - previous_unit_vec[E_AXIS]
#endif
};
// Convert delta vector to unit vector
normalize_junction_vector(junction_unit_vec);
const float junction_acceleration = limit_value_by_axis_maximum(block->acceleration, junction_unit_vec),
sin_theta_d2 = SQRT(0.5 * (1.0 - junction_cos_theta)); // Trig half angle identity. Always positive.
vmax_junction_sqr = (junction_acceleration * JUNCTION_DEVIATION_MM * sin_theta_d2) / (1.0 - sin_theta_d2);
if (block->millimeters < 1.0) {
// Fast acos approximation, minus the error bar to be safe
@@ -2160,7 +2171,7 @@ bool Planner::_populate_block(block_t * const block, bool split_move,
// If angle is greater than 135 degrees (octagon), find speed for approximate arc
if (junction_theta > RADIANS(135)) {
const float limit_sqr = block->millimeters / (RADIANS(180) - junction_theta) * JUNCTION_ACCELERATION;
const float limit_sqr = block->millimeters / (RADIANS(180) - junction_theta) * junction_acceleration;
NOMORE(vmax_junction_sqr, limit_sqr);
}
}