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Adapt speed/jerk code based on Prusa MK2 branch

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This commit is contained in:
Scott Lahteine 2016-10-11 02:00:29 -05:00
parent 8e1cc9332a
commit 1092319b19
1 changed files with 139 additions and 56 deletions
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189
Marlin/planner.cpp
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@ -85,7 +85,7 @@ float Planner::max_feedrate_mm_s[NUM_AXIS], // Max speeds in mm per second
Planner::axis_steps_per_mm[NUM_AXIS], Planner::axis_steps_per_mm[NUM_AXIS],
Planner::steps_to_mm[NUM_AXIS]; Planner::steps_to_mm[NUM_AXIS];
unsigned long Planner::max_acceleration_steps_per_s2[NUM_AXIS], uint32_t Planner::max_acceleration_steps_per_s2[NUM_AXIS],
Planner::max_acceleration_mm_per_s2[NUM_AXIS]; // Use M201 to override by software Planner::max_acceleration_mm_per_s2[NUM_AXIS]; // Use M201 to override by software
millis_t Planner::min_segment_time; millis_t Planner::min_segment_time;
@ -236,6 +236,7 @@ void Planner::reverse_pass() {
uint8_t b = BLOCK_MOD(block_buffer_head - 3); uint8_t b = BLOCK_MOD(block_buffer_head - 3);
while (b != tail) { while (b != tail) {
if (block[0] && (block[0]->flag & BLOCK_FLAG_START_FROM_FULL_HALT)) break;
b = prev_block_index(b); b = prev_block_index(b);
block[2] = block[1]; block[2] = block[1];
block[1] = block[0]; 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 // Bail if this is a zero-length block
if (block->step_event_count < MIN_STEPS_PER_SEGMENT) return; 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 // For a mixing extruder, get a magnified step_event_count for each
#if ENABLED(MIXING_EXTRUDER) #if ENABLED(MIXING_EXTRUDER)
for (uint8_t i = 0; i < MIXING_STEPPERS; i++) for (uint8_t i = 0; i < MIXING_STEPPERS; i++)
@ -1011,51 +1015,67 @@ void Planner::_buffer_line(const float &a, const float &b, const float &c, const
// Compute and limit the acceleration rate for the trapezoid generator. // Compute and limit the acceleration rate for the trapezoid generator.
float steps_per_mm = block->step_event_count / block->millimeters; 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]) { 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 { 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 // Limit acceleration per axis
block->acceleration_steps_per_s2 = ceil((block->steps[E_AXIS] ? acceleration : travel_acceleration) * steps_per_mm); LIMIT_ACCEL(X_AXIS);
if (max_acceleration_steps_per_s2[X_AXIS] < (block->acceleration_steps_per_s2 * block->steps[X_AXIS]) / block->step_event_count) LIMIT_ACCEL(Y_AXIS);
block->acceleration_steps_per_s2 = (max_acceleration_steps_per_s2[X_AXIS] * block->step_event_count) / block->steps[X_AXIS]; LIMIT_ACCEL(Z_AXIS);
if (max_acceleration_steps_per_s2[Y_AXIS] < (block->acceleration_steps_per_s2 * block->steps[Y_AXIS]) / block->step_event_count) LIMIT_ACCEL(E_AXIS);
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];
} }
block->acceleration = block->acceleration_steps_per_s2 / steps_per_mm; block->acceleration_steps_per_s2 = accel;
block->acceleration_rate = (long)(block->acceleration_steps_per_s2 * 16777216.0 / ((F_CPU) * 0.125)); 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 #if 0 // Use old jerk for now
float junction_deviation = 0.1; float junction_deviation = 0.1;
// Compute path unit vector // Compute path unit vector
double unit_vec[XYZ]; double unit_vec[XYZ] = {
delta_mm[X_AXIS] * inverse_millimeters,
delta_mm[Y_AXIS] * inverse_millimeters,
delta_mm[Z_AXIS] * inverse_millimeters
};
unit_vec[X_AXIS] = delta_mm[X_AXIS] * inverse_millimeters; /*
unit_vec[Y_AXIS] = delta_mm[Y_AXIS] * inverse_millimeters; Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
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
// 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,
// deviation is defined as the distance from the junction to the closest edge of the circle, collinear with the circle center.
// 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 The circular segment joining the two paths represents the path of centripetal acceleration.
// radius of the circle, defined indirectly by junction deviation. This may be also viewed as Solve for max velocity based on max acceleration about the radius of the circle, defined
// path width or max_jerk in the previous grbl version. This approach does not actually deviate indirectly by junction deviation.
// 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. This may be also viewed as path width or max_jerk in the previous grbl version. This approach
double vmax_junction = MINIMUM_PLANNER_SPEED; // Set default max junction speed 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. // 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) // 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. // 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] float cos_theta = - previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
- previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS] - previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
- previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ; - previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ;
// Skip and use default max junction speed for 0 degree acute junction. // Skip and use default max junction speed for 0 degree acute junction.
@ -1064,37 +1084,101 @@ void Planner::_buffer_line(const float &a, const float &b, const float &c, const
// Skip and avoid divide by zero for straight junctions at 180 degrees. Limit to min() of nominal speeds. // Skip and avoid divide by zero for straight junctions at 180 degrees. Limit to min() of nominal speeds.
if (cos_theta > -0.95) { if (cos_theta > -0.95) {
// Compute maximum junction velocity based on maximum acceleration and junction deviation // 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))); NOMORE(vmax_junction, sqrt(block->acceleration * junction_deviation * sin_theta_d2 / (1.0 - sin_theta_d2)));
} }
} }
} }
#endif #endif
// Start with a safe speed /**
float vmax_junction = max_jerk[X_AXIS] * 0.5, vmax_junction_factor = 1.0; * Adapted from Prusa MKS firmware
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); * Start with a safe speed (from which the machine may halt to stop immediately).
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; // 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 (moves_queued > 1 && previous_nominal_speed > 0.0001) {
//if ((fabs(previous_speed[X_AXIS]) > 0.0001) || (fabs(previous_speed[Y_AXIS]) > 0.0001)) { // Estimate a maximum velocity allowed at a joint of two successive segments.
vmax_junction = block->nominal_speed; // 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.
float dsx = fabs(current_speed[X_AXIS] - previous_speed[X_AXIS]), // The junction velocity will be shared between successive segments. Limit the junction velocity to their minimum.
dsy = fabs(current_speed[Y_AXIS] - previous_speed[Y_AXIS]), bool prev_speed_larger = previous_nominal_speed > block->nominal_speed;
dsz = fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]), float smaller_speed_factor = prev_speed_larger ? (block->nominal_speed / previous_nominal_speed) : (previous_nominal_speed / block->nominal_speed);
dse = fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]); // Pick the smaller of the nominal speeds. Higher speed shall not be achieved at the junction during coasting.
if (dsx > max_jerk[X_AXIS]) NOMORE(vmax_junction_factor, max_jerk[X_AXIS] / dsx); vmax_junction = prev_speed_larger ? block->nominal_speed : previous_nominal_speed;
if (dsy > max_jerk[Y_AXIS]) NOMORE(vmax_junction_factor, max_jerk[Y_AXIS] / dsy); // Factor to multiply the previous / current nominal velocities to get componentwise limited velocities.
if (dsz > max_jerk[Z_AXIS]) NOMORE(vmax_junction_factor, max_jerk[Z_AXIS] / dsz); float v_factor = 1.f;
if (dse > max_jerk[E_AXIS]) NOMORE(vmax_junction_factor, max_jerk[E_AXIS] / dse); limited = false;
// Now limit the jerk in all axes.
vmax_junction = min(previous_nominal_speed, vmax_junction * vmax_junction_factor); // Limit speed to max previous speed 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; block->max_entry_speed = vmax_junction;
// Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED. // 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 // 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 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. // the maximum junction speed and may always be ignored for any speed reduction checks.
block->flag &= ~BLOCK_FLAG_NOMINAL_LENGTH; block->flag |= BLOCK_FLAG_RECALCULATE | (block->nominal_speed <= v_allowable ? BLOCK_FLAG_NOMINAL_LENGTH : 0);
if (block->nominal_speed <= v_allowable) block->flag |= BLOCK_FLAG_NOMINAL_LENGTH;
block->flag |= BLOCK_FLAG_RECALCULATE; // Always calculate trapezoid for new block
// Update previous path unit_vector and nominal speed // Update previous path unit_vector and nominal speed
memcpy(previous_speed, current_speed, sizeof(previous_speed)); memcpy(previous_speed, current_speed, sizeof(previous_speed));
previous_nominal_speed = block->nominal_speed; previous_nominal_speed = block->nominal_speed;
previous_safe_speed = safe_speed;
#if ENABLED(LIN_ADVANCE) #if ENABLED(LIN_ADVANCE)