2 planner.c - buffers movement commands and manages the acceleration profile plan
5 Copyright (c) 2009-2011 Simen Svale Skogsrud
7 Grbl is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 Grbl is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with Grbl. If not, see <http://www.gnu.org/licenses/>.
21 /* The ring buffer implementation gleaned from the wiring_serial library by David A. Mellis. */
24 Reasoning behind the mathematics in this module (in the key of 'Mathematica'):
26 s == speed, a == acceleration, t == time, d == distance
30 Speed[s_, a_, t_] := s + (a*t)
31 Travel[s_, a_, t_] := Integrate[Speed[s, a, t], t]
33 Distance to reach a specific speed with a constant acceleration:
35 Solve[{Speed[s, a, t] == m, Travel[s, a, t] == d}, d, t]
36 d -> (m^2 - s^2)/(2 a) --> estimate_acceleration_distance()
38 Speed after a given distance of travel with constant acceleration:
40 Solve[{Speed[s, a, t] == m, Travel[s, a, t] == d}, m, t]
41 m -> Sqrt[2 a d + s^2]
43 DestinationSpeed[s_, a_, d_] := Sqrt[2 a d + s^2]
45 When to start braking (di) to reach a specified destionation speed (s2) after accelerating
46 from initial speed s1 without ever stopping at a plateau:
48 Solve[{DestinationSpeed[s1, a, di] == DestinationSpeed[s2, a, d - di]}, di]
49 di -> (2 a d - s1^2 + s2^2)/(4 a) --> intersection_distance()
51 IntersectionDistance[s1_, s2_, a_, d_] := (2 a d - s1^2 + s2^2)/(4 a)
57 #include "temperature.h"
61 //===========================================================================
62 //=============================public variables ============================
63 //===========================================================================
65 unsigned long minsegmenttime;
66 float max_feedrate[4]; // set the max speeds
67 float axis_steps_per_unit[4];
68 unsigned long max_acceleration_units_per_sq_second[4]; // Use M201 to override by software
69 float minimumfeedrate;
70 float acceleration; // Normal acceleration mm/s^2 THIS IS THE DEFAULT ACCELERATION for all moves. M204 SXXXX
71 float retract_acceleration; // mm/s^2 filament pull-pack and push-forward while standing still in the other axis M204 TXXXX
72 float max_xy_jerk; //speed than can be stopped at once, if i understand correctly.
75 float mintravelfeedrate;
76 unsigned long axis_steps_per_sqr_second[NUM_AXIS];
78 // The current position of the tool in absolute steps
79 long position[4]; //rescaled from extern when axis_steps_per_unit are changed by gcode
80 static float previous_speed[4]; // Speed of previous path line segment
81 static float previous_nominal_speed; // Nominal speed of previous path line segment
83 extern volatile int extrudemultiply; // Sets extrude multiply factor (in percent)
86 float autotemp_max=250;
87 float autotemp_min=210;
88 float autotemp_factor=0.1;
89 bool autotemp_enabled=false;
92 //===========================================================================
93 //=================semi-private variables, used in inline functions =====
94 //===========================================================================
95 block_t block_buffer[BLOCK_BUFFER_SIZE]; // A ring buffer for motion instfructions
96 volatile unsigned char block_buffer_head; // Index of the next block to be pushed
97 volatile unsigned char block_buffer_tail; // Index of the block to process now
99 //===========================================================================
100 //=============================private variables ============================
101 //===========================================================================
102 #ifdef PREVENT_DANGEROUS_EXTRUDE
103 bool allow_cold_extrude=false;
105 #ifdef XY_FREQUENCY_LIMIT
106 // Used for the frequency limit
107 static unsigned char old_direction_bits = 0; // Old direction bits. Used for speed calculations
108 static long x_segment_time[3]={0,0,0}; // Segment times (in us). Used for speed calculations
109 static long y_segment_time[3]={0,0,0};
112 // Returns the index of the next block in the ring buffer
113 // NOTE: Removed modulo (%) operator, which uses an expensive divide and multiplication.
114 static int8_t next_block_index(int8_t block_index) {
116 if (block_index == BLOCK_BUFFER_SIZE) { block_index = 0; }
121 // Returns the index of the previous block in the ring buffer
122 static int8_t prev_block_index(int8_t block_index) {
123 if (block_index == 0) { block_index = BLOCK_BUFFER_SIZE; }
128 //===========================================================================
129 //=============================functions ============================
130 //===========================================================================
132 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
133 // given acceleration:
134 FORCE_INLINE float estimate_acceleration_distance(float initial_rate, float target_rate, float acceleration)
136 if (acceleration!=0) {
137 return((target_rate*target_rate-initial_rate*initial_rate)/
141 return 0.0; // acceleration was 0, set acceleration distance to 0
145 // This function gives you the point at which you must start braking (at the rate of -acceleration) if
146 // you started at speed initial_rate and accelerated until this point and want to end at the final_rate after
147 // a total travel of distance. This can be used to compute the intersection point between acceleration and
148 // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)
150 FORCE_INLINE float intersection_distance(float initial_rate, float final_rate, float acceleration, float distance)
152 if (acceleration!=0) {
153 return((2.0*acceleration*distance-initial_rate*initial_rate+final_rate*final_rate)/
154 (4.0*acceleration) );
157 return 0.0; // acceleration was 0, set intersection distance to 0
161 // Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
163 void calculate_trapezoid_for_block(block_t *block, float entry_factor, float exit_factor) {
164 unsigned long initial_rate = ceil(block->nominal_rate*entry_factor); // (step/min)
165 unsigned long final_rate = ceil(block->nominal_rate*exit_factor); // (step/min)
167 // Limit minimal step rate (Otherwise the timer will overflow.)
168 if(initial_rate <120) {initial_rate=120; }
169 if(final_rate < 120) {final_rate=120; }
171 long acceleration = block->acceleration_st;
172 int32_t accelerate_steps =
173 ceil(estimate_acceleration_distance(block->initial_rate, block->nominal_rate, acceleration));
174 int32_t decelerate_steps =
175 floor(estimate_acceleration_distance(block->nominal_rate, block->final_rate, -acceleration));
177 // Calculate the size of Plateau of Nominal Rate.
178 int32_t plateau_steps = block->step_event_count-accelerate_steps-decelerate_steps;
180 // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will
181 // have to use intersection_distance() to calculate when to abort acceleration and start braking
182 // in order to reach the final_rate exactly at the end of this block.
183 if (plateau_steps < 0) {
184 accelerate_steps = ceil(
185 intersection_distance(block->initial_rate, block->final_rate, acceleration, block->step_event_count));
186 accelerate_steps = max(accelerate_steps,0); // Check limits due to numerical round-off
187 accelerate_steps = min(accelerate_steps,block->step_event_count);
192 volatile long initial_advance = block->advance*entry_factor*entry_factor;
193 volatile long final_advance = block->advance*exit_factor*exit_factor;
196 // block->accelerate_until = accelerate_steps;
197 // block->decelerate_after = accelerate_steps+plateau_steps;
198 CRITICAL_SECTION_START; // Fill variables used by the stepper in a critical section
199 if(block->busy == false) { // Don't update variables if block is busy.
200 block->accelerate_until = accelerate_steps;
201 block->decelerate_after = accelerate_steps+plateau_steps;
202 block->initial_rate = initial_rate;
203 block->final_rate = final_rate;
205 block->initial_advance = initial_advance;
206 block->final_advance = final_advance;
209 CRITICAL_SECTION_END;
212 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
213 // acceleration within the allotted distance.
214 FORCE_INLINE float max_allowable_speed(float acceleration, float target_velocity, float distance) {
215 return sqrt(target_velocity*target_velocity-2*acceleration*distance);
218 // "Junction jerk" in this context is the immediate change in speed at the junction of two blocks.
219 // This method will calculate the junction jerk as the euclidean distance between the nominal
220 // velocities of the respective blocks.
221 //inline float junction_jerk(block_t *before, block_t *after) {
223 // pow((before->speed_x-after->speed_x), 2)+pow((before->speed_y-after->speed_y), 2));
227 // The kernel called by planner_recalculate() when scanning the plan from last to first entry.
228 void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *next) {
229 if(!current) { return; }
232 // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
233 // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
234 // check for maximum allowable speed reductions to ensure maximum possible planned speed.
235 if (current->entry_speed != current->max_entry_speed) {
237 // If nominal length true, max junction speed is guaranteed to be reached. Only compute
238 // for max allowable speed if block is decelerating and nominal length is false.
239 if ((!current->nominal_length_flag) && (current->max_entry_speed > next->entry_speed)) {
240 current->entry_speed = min( current->max_entry_speed,
241 max_allowable_speed(-current->acceleration,next->entry_speed,current->millimeters));
243 current->entry_speed = current->max_entry_speed;
245 current->recalculate_flag = true;
248 } // Skip last block. Already initialized and set for recalculation.
251 // planner_recalculate() needs to go over the current plan twice. Once in reverse and once forward. This
252 // implements the reverse pass.
253 void planner_reverse_pass() {
254 uint8_t block_index = block_buffer_head;
255 if(((block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1)) > 3) {
256 block_index = (block_buffer_head - 3) & (BLOCK_BUFFER_SIZE - 1);
257 block_t *block[3] = { NULL, NULL, NULL };
258 while(block_index != block_buffer_tail) {
259 block_index = prev_block_index(block_index);
262 block[0] = &block_buffer[block_index];
263 planner_reverse_pass_kernel(block[0], block[1], block[2]);
268 // The kernel called by planner_recalculate() when scanning the plan from first to last entry.
269 void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *next) {
270 if(!previous) { return; }
272 // If the previous block is an acceleration block, but it is not long enough to complete the
273 // full speed change within the block, we need to adjust the entry speed accordingly. Entry
274 // speeds have already been reset, maximized, and reverse planned by reverse planner.
275 // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
276 if (!previous->nominal_length_flag) {
277 if (previous->entry_speed < current->entry_speed) {
278 double entry_speed = min( current->entry_speed,
279 max_allowable_speed(-previous->acceleration,previous->entry_speed,previous->millimeters) );
281 // Check for junction speed change
282 if (current->entry_speed != entry_speed) {
283 current->entry_speed = entry_speed;
284 current->recalculate_flag = true;
290 // planner_recalculate() needs to go over the current plan twice. Once in reverse and once forward. This
291 // implements the forward pass.
292 void planner_forward_pass() {
293 uint8_t block_index = block_buffer_tail;
294 block_t *block[3] = { NULL, NULL, NULL };
296 while(block_index != block_buffer_head) {
299 block[2] = &block_buffer[block_index];
300 planner_forward_pass_kernel(block[0],block[1],block[2]);
301 block_index = next_block_index(block_index);
303 planner_forward_pass_kernel(block[1], block[2], NULL);
306 // Recalculates the trapezoid speed profiles for all blocks in the plan according to the
307 // entry_factor for each junction. Must be called by planner_recalculate() after
308 // updating the blocks.
309 void planner_recalculate_trapezoids() {
310 int8_t block_index = block_buffer_tail;
312 block_t *next = NULL;
314 while(block_index != block_buffer_head) {
316 next = &block_buffer[block_index];
318 // Recalculate if current block entry or exit junction speed has changed.
319 if (current->recalculate_flag || next->recalculate_flag) {
320 // NOTE: Entry and exit factors always > 0 by all previous logic operations.
321 calculate_trapezoid_for_block(current, current->entry_speed/current->nominal_speed,
322 next->entry_speed/current->nominal_speed);
323 current->recalculate_flag = false; // Reset current only to ensure next trapezoid is computed
326 block_index = next_block_index( block_index );
328 // Last/newest block in buffer. Exit speed is set with MINIMUM_PLANNER_SPEED. Always recalculated.
330 calculate_trapezoid_for_block(next, next->entry_speed/next->nominal_speed,
331 MINIMUM_PLANNER_SPEED/next->nominal_speed);
332 next->recalculate_flag = false;
336 // Recalculates the motion plan according to the following algorithm:
338 // 1. Go over every block in reverse order and calculate a junction speed reduction (i.e. block_t.entry_factor)
340 // a. The junction jerk is within the set limit
341 // b. No speed reduction within one block requires faster deceleration than the one, true constant
343 // 2. Go over every block in chronological order and dial down junction speed reduction values if
344 // a. The speed increase within one block would require faster accelleration than the one, true
345 // constant acceleration.
347 // When these stages are complete all blocks have an entry_factor that will allow all speed changes to
348 // be performed using only the one, true constant acceleration, and where no junction jerk is jerkier than
349 // the set limit. Finally it will:
351 // 3. Recalculate trapezoids for all blocks.
353 void planner_recalculate() {
354 planner_reverse_pass();
355 planner_forward_pass();
356 planner_recalculate_trapezoids();
360 block_buffer_head = 0;
361 block_buffer_tail = 0;
362 memset(position, 0, sizeof(position)); // clear position
363 previous_speed[0] = 0.0;
364 previous_speed[1] = 0.0;
365 previous_speed[2] = 0.0;
366 previous_speed[3] = 0.0;
367 previous_nominal_speed = 0.0;
377 if(!autotemp_enabled){
380 if(degTargetHotend0()+2<autotemp_min) { //probably temperature set to zero.
385 uint8_t block_index = block_buffer_tail;
387 while(block_index != block_buffer_head) {
388 if((block_buffer[block_index].steps_x != 0) ||
389 (block_buffer[block_index].steps_y != 0) ||
390 (block_buffer[block_index].steps_z != 0)) {
391 float se=(float(block_buffer[block_index].steps_e)/float(block_buffer[block_index].step_event_count))*block_buffer[block_index].nominal_speed;
398 block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1);
401 float g=autotemp_min+high*autotemp_factor;
409 t=AUTOTEMP_OLDWEIGHT*oldt+(1-AUTOTEMP_OLDWEIGHT)*t;
416 void check_axes_activity() {
417 unsigned char x_active = 0;
418 unsigned char y_active = 0;
419 unsigned char z_active = 0;
420 unsigned char e_active = 0;
421 unsigned char fan_speed = 0;
422 unsigned char tail_fan_speed = 0;
425 if(block_buffer_tail != block_buffer_head) {
426 uint8_t block_index = block_buffer_tail;
427 tail_fan_speed = block_buffer[block_index].fan_speed;
428 while(block_index != block_buffer_head) {
429 block = &block_buffer[block_index];
430 if(block->steps_x != 0) x_active++;
431 if(block->steps_y != 0) y_active++;
432 if(block->steps_z != 0) z_active++;
433 if(block->steps_e != 0) e_active++;
434 if(block->fan_speed != 0) fan_speed++;
435 block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1);
441 analogWrite(FAN_PIN,FanSpeed); // If buffer is empty use current fan speed
445 if((DISABLE_X) && (x_active == 0)) disable_x();
446 if((DISABLE_Y) && (y_active == 0)) disable_y();
447 if((DISABLE_Z) && (z_active == 0)) disable_z();
448 if((DISABLE_E) && (e_active == 0)) { disable_e0();disable_e1();disable_e2(); }
450 if((FanSpeed == 0) && (fan_speed ==0)) {
451 analogWrite(FAN_PIN, 0);
454 if (FanSpeed != 0 && tail_fan_speed !=0) {
455 analogWrite(FAN_PIN,tail_fan_speed);
464 float junction_deviation = 0.1;
465 // Add a new linear movement to the buffer. steps_x, _y and _z is the absolute position in
466 // mm. Microseconds specify how many microseconds the move should take to perform. To aid acceleration
467 // calculation the caller must also provide the physical length of the line in millimeters.
468 void plan_buffer_line(const float &x, const float &y, const float &z, const float &e, float feed_rate, const uint8_t &extruder)
470 // Calculate the buffer head after we push this byte
471 int next_buffer_head = next_block_index(block_buffer_head);
473 // If the buffer is full: good! That means we are well ahead of the robot.
474 // Rest here until there is room in the buffer.
475 while(block_buffer_tail == next_buffer_head) {
477 manage_inactivity(1);
481 // The target position of the tool in absolute steps
482 // Calculate target position in absolute steps
483 //this should be done after the wait, because otherwise a M92 code within the gcode disrupts this calculation somehow
485 target[X_AXIS] = lround(x*axis_steps_per_unit[X_AXIS]);
486 target[Y_AXIS] = lround(y*axis_steps_per_unit[Y_AXIS]);
487 target[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]);
488 target[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]);
490 #ifdef PREVENT_DANGEROUS_EXTRUDE
491 if(target[E_AXIS]!=position[E_AXIS])
492 if(degHotend(active_extruder)<EXTRUDE_MINTEMP && !allow_cold_extrude)
494 position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part
496 SERIAL_ECHOLNPGM(MSG_ERR_COLD_EXTRUDE_STOP);
498 #ifdef PREVENT_LENGTHY_EXTRUDE
499 if(labs(target[E_AXIS]-position[E_AXIS])>axis_steps_per_unit[E_AXIS]*EXTRUDE_MAXLENGTH)
501 position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part
503 SERIAL_ECHOLNPGM(MSG_ERR_LONG_EXTRUDE_STOP);
508 // Prepare to set up new block
509 block_t *block = &block_buffer[block_buffer_head];
511 // Mark block as not busy (Not executed by the stepper interrupt)
514 // Number of steps for each axis
515 block->steps_x = labs(target[X_AXIS]-position[X_AXIS]);
516 block->steps_y = labs(target[Y_AXIS]-position[Y_AXIS]);
517 block->steps_z = labs(target[Z_AXIS]-position[Z_AXIS]);
518 block->steps_e = labs(target[E_AXIS]-position[E_AXIS]);
519 block->steps_e *= extrudemultiply;
520 block->steps_e /= 100;
521 block->step_event_count = max(block->steps_x, max(block->steps_y, max(block->steps_z, block->steps_e)));
523 // Bail if this is a zero-length block
524 if (block->step_event_count <= dropsegments) { return; };
526 block->fan_speed = FanSpeed;
528 // Compute direction bits for this block
529 block->direction_bits = 0;
530 if (target[X_AXIS] < position[X_AXIS]) { block->direction_bits |= (1<<X_AXIS); }
531 if (target[Y_AXIS] < position[Y_AXIS]) { block->direction_bits |= (1<<Y_AXIS); }
532 if (target[Z_AXIS] < position[Z_AXIS]) { block->direction_bits |= (1<<Z_AXIS); }
533 if (target[E_AXIS] < position[E_AXIS]) { block->direction_bits |= (1<<E_AXIS); }
535 block->active_extruder = extruder;
538 if(block->steps_x != 0) enable_x();
539 if(block->steps_y != 0) enable_y();
540 #ifndef Z_LATE_ENABLE
541 if(block->steps_z != 0) enable_z();
545 if(block->steps_e != 0) { enable_e0();enable_e1();enable_e2(); }
547 if (block->steps_e == 0) {
548 if(feed_rate<mintravelfeedrate) feed_rate=mintravelfeedrate;
551 if(feed_rate<minimumfeedrate) feed_rate=minimumfeedrate;
555 delta_mm[X_AXIS] = (target[X_AXIS]-position[X_AXIS])/axis_steps_per_unit[X_AXIS];
556 delta_mm[Y_AXIS] = (target[Y_AXIS]-position[Y_AXIS])/axis_steps_per_unit[Y_AXIS];
557 delta_mm[Z_AXIS] = (target[Z_AXIS]-position[Z_AXIS])/axis_steps_per_unit[Z_AXIS];
558 delta_mm[E_AXIS] = ((target[E_AXIS]-position[E_AXIS])/axis_steps_per_unit[E_AXIS])*extrudemultiply/100.0;
559 if ( block->steps_x <=dropsegments && block->steps_y <=dropsegments && block->steps_z <=dropsegments ) {
560 block->millimeters = fabs(delta_mm[E_AXIS]);
562 block->millimeters = sqrt(square(delta_mm[X_AXIS]) + square(delta_mm[Y_AXIS]) + square(delta_mm[Z_AXIS]));
564 float inverse_millimeters = 1.0/block->millimeters; // Inverse millimeters to remove multiple divides
566 // Calculate speed in mm/second for each axis. No divide by zero due to previous checks.
567 float inverse_second = feed_rate * inverse_millimeters;
569 int moves_queued=(block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1);
571 // slow down when de buffer starts to empty, rather than wait at the corner for a buffer refill
573 if(moves_queued < (BLOCK_BUFFER_SIZE * 0.5) && moves_queued > 1) feed_rate = feed_rate*moves_queued / (BLOCK_BUFFER_SIZE * 0.5);
577 // segment time im micro seconds
578 unsigned long segment_time = lround(1000000.0/inverse_second);
579 if ((moves_queued > 1) && (moves_queued < (BLOCK_BUFFER_SIZE * 0.5))) {
580 if (segment_time < minsegmenttime) { // buffer is draining, add extra time. The amount of time added increases if the buffer is still emptied more.
581 inverse_second=1000000.0/(segment_time+lround(2*(minsegmenttime-segment_time)/moves_queued));
585 // END OF SLOW DOWN SECTION
588 block->nominal_speed = block->millimeters * inverse_second; // (mm/sec) Always > 0
589 block->nominal_rate = ceil(block->step_event_count * inverse_second); // (step/sec) Always > 0
591 // Calculate and limit speed in mm/sec for each axis
592 float current_speed[4];
593 float speed_factor = 1.0; //factor <=1 do decrease speed
594 for(int i=0; i < 4; i++) {
595 current_speed[i] = delta_mm[i] * inverse_second;
596 if(fabs(current_speed[i]) > max_feedrate[i])
597 speed_factor = min(speed_factor, max_feedrate[i] / fabs(current_speed[i]));
600 // Max segement time in us.
601 #ifdef XY_FREQUENCY_LIMIT
602 #define MAX_FREQ_TIME (1000000.0/XY_FREQUENCY_LIMIT)
604 // Check and limit the xy direction change frequency
605 unsigned char direction_change = block->direction_bits ^ old_direction_bits;
606 old_direction_bits = block->direction_bits;
608 if((direction_change & (1<<X_AXIS)) == 0) {
609 x_segment_time[0] += segment_time;
612 x_segment_time[2] = x_segment_time[1];
613 x_segment_time[1] = x_segment_time[0];
614 x_segment_time[0] = segment_time;
616 if((direction_change & (1<<Y_AXIS)) == 0) {
617 y_segment_time[0] += segment_time;
620 y_segment_time[2] = y_segment_time[1];
621 y_segment_time[1] = y_segment_time[0];
622 y_segment_time[0] = segment_time;
624 long max_x_segment_time = max(x_segment_time[0], max(x_segment_time[1], x_segment_time[2]));
625 long max_y_segment_time = max(y_segment_time[0], max(y_segment_time[1], y_segment_time[2]));
626 long min_xy_segment_time =min(max_x_segment_time, max_y_segment_time);
627 if(min_xy_segment_time < MAX_FREQ_TIME) speed_factor = min(speed_factor, speed_factor * (float)min_xy_segment_time / (float)MAX_FREQ_TIME);
631 if( speed_factor < 1.0) {
632 for(unsigned char i=0; i < 4; i++) {
633 current_speed[i] *= speed_factor;
635 block->nominal_speed *= speed_factor;
636 block->nominal_rate *= speed_factor;
639 // Compute and limit the acceleration rate for the trapezoid generator.
640 float steps_per_mm = block->step_event_count/block->millimeters;
641 if(block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0) {
642 block->acceleration_st = ceil(retract_acceleration * steps_per_mm); // convert to: acceleration steps/sec^2
645 block->acceleration_st = ceil(acceleration * steps_per_mm); // convert to: acceleration steps/sec^2
646 // Limit acceleration per axis
647 if(((float)block->acceleration_st * (float)block->steps_x / (float)block->step_event_count) > axis_steps_per_sqr_second[X_AXIS])
648 block->acceleration_st = axis_steps_per_sqr_second[X_AXIS];
649 if(((float)block->acceleration_st * (float)block->steps_y / (float)block->step_event_count) > axis_steps_per_sqr_second[Y_AXIS])
650 block->acceleration_st = axis_steps_per_sqr_second[Y_AXIS];
651 if(((float)block->acceleration_st * (float)block->steps_e / (float)block->step_event_count) > axis_steps_per_sqr_second[E_AXIS])
652 block->acceleration_st = axis_steps_per_sqr_second[E_AXIS];
653 if(((float)block->acceleration_st * (float)block->steps_z / (float)block->step_event_count ) > axis_steps_per_sqr_second[Z_AXIS])
654 block->acceleration_st = axis_steps_per_sqr_second[Z_AXIS];
656 block->acceleration = block->acceleration_st / steps_per_mm;
657 block->acceleration_rate = (long)((float)block->acceleration_st * 8.388608);
659 #if 0 // Use old jerk for now
660 // Compute path unit vector
663 unit_vec[X_AXIS] = delta_mm[X_AXIS]*inverse_millimeters;
664 unit_vec[Y_AXIS] = delta_mm[Y_AXIS]*inverse_millimeters;
665 unit_vec[Z_AXIS] = delta_mm[Z_AXIS]*inverse_millimeters;
667 // Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
668 // Let a circle be tangent to both previous and current path line segments, where the junction
669 // deviation is defined as the distance from the junction to the closest edge of the circle,
670 // colinear with the circle center. The circular segment joining the two paths represents the
671 // path of centripetal acceleration. Solve for max velocity based on max acceleration about the
672 // radius of the circle, defined indirectly by junction deviation. This may be also viewed as
673 // path width or max_jerk in the previous grbl version. This approach does not actually deviate
674 // from path, but used as a robust way to compute cornering speeds, as it takes into account the
675 // nonlinearities of both the junction angle and junction velocity.
676 double vmax_junction = MINIMUM_PLANNER_SPEED; // Set default max junction speed
678 // Skip first block or when previous_nominal_speed is used as a flag for homing and offset cycles.
679 if ((block_buffer_head != block_buffer_tail) && (previous_nominal_speed > 0.0)) {
680 // Compute cosine of angle between previous and current path. (prev_unit_vec is negative)
681 // NOTE: Max junction velocity is computed without sin() or acos() by trig half angle identity.
682 double cos_theta = - previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
683 - previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
684 - previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ;
686 // Skip and use default max junction speed for 0 degree acute junction.
687 if (cos_theta < 0.95) {
688 vmax_junction = min(previous_nominal_speed,block->nominal_speed);
689 // Skip and avoid divide by zero for straight junctions at 180 degrees. Limit to min() of nominal speeds.
690 if (cos_theta > -0.95) {
691 // Compute maximum junction velocity based on maximum acceleration and junction deviation
692 double sin_theta_d2 = sqrt(0.5*(1.0-cos_theta)); // Trig half angle identity. Always positive.
693 vmax_junction = min(vmax_junction,
694 sqrt(block->acceleration * junction_deviation * sin_theta_d2/(1.0-sin_theta_d2)) );
699 // Start with a safe speed
700 float vmax_junction = max_xy_jerk/2;
701 if(fabs(current_speed[Z_AXIS]) > max_z_jerk/2)
702 vmax_junction = max_z_jerk/2;
703 vmax_junction = min(vmax_junction, block->nominal_speed);
704 if(fabs(current_speed[E_AXIS]) > max_e_jerk/2)
705 vmax_junction = min(vmax_junction, max_e_jerk/2);
707 if ((moves_queued > 1) && (previous_nominal_speed > 0.0001)) {
708 float jerk = sqrt(pow((current_speed[X_AXIS]-previous_speed[X_AXIS]), 2)+pow((current_speed[Y_AXIS]-previous_speed[Y_AXIS]), 2));
709 if((fabs(previous_speed[X_AXIS]) > 0.0001) || (fabs(previous_speed[Y_AXIS]) > 0.0001)) {
710 vmax_junction = block->nominal_speed;
712 if (jerk > max_xy_jerk) {
713 vmax_junction *= (max_xy_jerk/jerk);
715 if(fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]) > max_z_jerk) {
716 vmax_junction *= (max_z_jerk/fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]));
718 if(fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]) > max_e_jerk) {
719 vmax_junction *= (max_e_jerk/fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]));
722 block->max_entry_speed = vmax_junction;
724 // Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED.
725 double v_allowable = max_allowable_speed(-block->acceleration,MINIMUM_PLANNER_SPEED,block->millimeters);
726 block->entry_speed = min(vmax_junction, v_allowable);
728 // Initialize planner efficiency flags
729 // Set flag if block will always reach maximum junction speed regardless of entry/exit speeds.
730 // If a block can de/ac-celerate from nominal speed to zero within the length of the block, then
731 // the current block and next block junction speeds are guaranteed to always be at their maximum
732 // junction speeds in deceleration and acceleration, respectively. This is due to how the current
733 // block nominal speed limits both the current and next maximum junction speeds. Hence, in both
734 // the reverse and forward planners, the corresponding block junction speed will always be at the
735 // the maximum junction speed and may always be ignored for any speed reduction checks.
736 if (block->nominal_speed <= v_allowable) { block->nominal_length_flag = true; }
737 else { block->nominal_length_flag = false; }
738 block->recalculate_flag = true; // Always calculate trapezoid for new block
740 // Update previous path unit_vector and nominal speed
741 memcpy(previous_speed, current_speed, sizeof(previous_speed)); // previous_speed[] = current_speed[]
742 previous_nominal_speed = block->nominal_speed;
746 // Calculate advance rate
747 if((block->steps_e == 0) || (block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0)) {
748 block->advance_rate = 0;
752 long acc_dist = estimate_acceleration_distance(0, block->nominal_rate, block->acceleration_st);
753 float advance = (STEPS_PER_CUBIC_MM_E * EXTRUDER_ADVANCE_K) *
754 (current_speed[E_AXIS] * current_speed[E_AXIS] * EXTRUTION_AREA * EXTRUTION_AREA)*256;
755 block->advance = advance;
757 block->advance_rate = 0;
760 block->advance_rate = advance / (float)acc_dist;
765 SERIAL_ECHOPGM("advance :");
766 SERIAL_ECHO(block->advance/256.0);
767 SERIAL_ECHOPGM("advance rate :");
768 SERIAL_ECHOLN(block->advance_rate/256.0);
772 calculate_trapezoid_for_block(block, block->entry_speed/block->nominal_speed,
773 MINIMUM_PLANNER_SPEED/block->nominal_speed);
776 block_buffer_head = next_buffer_head;
779 memcpy(position, target, sizeof(target)); // position[] = target[]
781 planner_recalculate();
786 void plan_set_position(const float &x, const float &y, const float &z, const float &e)
788 position[X_AXIS] = lround(x*axis_steps_per_unit[X_AXIS]);
789 position[Y_AXIS] = lround(y*axis_steps_per_unit[Y_AXIS]);
790 position[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]);
791 position[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]);
792 st_set_position(position[X_AXIS], position[Y_AXIS], position[Z_AXIS], position[E_AXIS]);
793 previous_nominal_speed = 0.0; // Resets planner junction speeds. Assumes start from rest.
794 previous_speed[0] = 0.0;
795 previous_speed[1] = 0.0;
796 previous_speed[2] = 0.0;
797 previous_speed[3] = 0.0;
800 void plan_set_e_position(const float &e)
802 position[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]);
803 st_set_e_position(position[E_AXIS]);
806 uint8_t movesplanned()
808 return (block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1);
811 void allow_cold_extrudes(bool allow)
813 #ifdef PREVENT_DANGEROUS_EXTRUDE
814 allow_cold_extrude=allow;