Files

planner.cpp
/* planner.c - buffers movement commands and manages the acceleration profile plan Part of Grbl Copyright (c) 2009-2011 Simen Svale Skogsrud Grbl is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Grbl is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Grbl. If not, see <http://www.gnu.org/licenses/>. */ /* The ring buffer implementation gleaned from the wiring_serial library by David A. Mellis. */ /* Reasoning behind the mathematics in this module (in the key of 'Mathematica'): s == speed, a == acceleration, t == time, d == distance Basic definitions: Speed[s_, a_, t_] := s + (a*t) Travel[s_, a_, t_] := Integrate[Speed[s, a, t], t] Distance to reach a specific speed with a constant acceleration: Solve[{Speed[s, a, t] == m, Travel[s, a, t] == d}, d, t] d -> (m^2 - s^2)/(2 a) --> estimate_acceleration_distance() Speed after a given distance of travel with constant acceleration: Solve[{Speed[s, a, t] == m, Travel[s, a, t] == d}, m, t] m -> Sqrt[2 a d + s^2] DestinationSpeed[s_, a_, d_] := Sqrt[2 a d + s^2] When to start braking (di) to reach a specified destionation speed (s2) after accelerating from initial speed s1 without ever stopping at a plateau: Solve[{DestinationSpeed[s1, a, di] == DestinationSpeed[s2, a, d - di]}, di] di -> (2 a d - s1^2 + s2^2)/(4 a) --> intersection_distance() IntersectionDistance[s1_, s2_, a_, d_] := (2 a d - s1^2 + s2^2)/(4 a) */ #include "Marlin.h" #include "planner.h" #include "stepper.h" #include "temperature.h" #include "ultralcd.h" #include "language.h" //=========================================================================== //=============================public variables ============================ //=========================================================================== unsigned long minsegmenttime; float max_feedrate[4]; // set the max speeds float axis_steps_per_unit[4]; unsigned long max_acceleration_units_per_sq_second[4]; // Use M201 to override by software float minimumfeedrate; float acceleration; // Normal acceleration mm/s^2 THIS IS THE DEFAULT ACCELERATION for all moves. M204 SXXXX float retract_acceleration; // mm/s^2 filament pull-pack and push-forward while standing still in the other axis M204 TXXXX float max_xy_jerk; //speed than can be stopped at once, if i understand correctly. float max_z_jerk; float max_e_jerk; float mintravelfeedrate; unsigned long axis_steps_per_sqr_second[NUM_AXIS]; // The current position of the tool in absolute steps long position[4]; //rescaled from extern when axis_steps_per_unit are changed by gcode static float previous_speed[4]; // Speed of previous path line segment static float previous_nominal_speed; // Nominal speed of previous path line segment #ifdef AUTOTEMP float autotemp_max=250; float autotemp_min=210; float autotemp_factor=0.1; bool autotemp_enabled=false; #endif //=========================================================================== //=================semi-private variables, used in inline functions ===== //=========================================================================== block_t block_buffer[BLOCK_BUFFER_SIZE]; // A ring buffer for motion instfructions volatile unsigned char block_buffer_head; // Index of the next block to be pushed volatile unsigned char block_buffer_tail; // Index of the block to process now //=========================================================================== //=============================private variables ============================ //=========================================================================== #ifdef PREVENT_DANGEROUS_EXTRUDE float extrude_min_temp=EXTRUDE_MINTEMP; #endif #ifdef XY_FREQUENCY_LIMIT #define MAX_FREQ_TIME (1000000.0/XY_FREQUENCY_LIMIT) // Used for the frequency limit static unsigned char old_direction_bits = 0; // Old direction bits. Used for speed calculations static long x_segment_time[3]={MAX_FREQ_TIME + 1,0,0}; // Segment times (in us). Used for speed calculations static long y_segment_time[3]={MAX_FREQ_TIME + 1,0,0}; #endif // Returns the index of the next block in the ring buffer // NOTE: Removed modulo (%) operator, which uses an expensive divide and multiplication. static int8_t next_block_index(int8_t block_index) { block_index++; if (block_index == BLOCK_BUFFER_SIZE) { block_index = 0; } return(block_index); } // Returns the index of the previous block in the ring buffer static int8_t prev_block_index(int8_t block_index) { if (block_index == 0) { block_index = BLOCK_BUFFER_SIZE; } block_index--; return(block_index); } //=========================================================================== //=============================functions ============================ //=========================================================================== // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the // given acceleration: FORCE_INLINE float estimate_acceleration_distance(float initial_rate, float target_rate, float acceleration) { if (acceleration!=0) { return((target_rate*target_rate-initial_rate*initial_rate)/ (2.0*acceleration)); } else { return 0.0; // acceleration was 0, set acceleration distance to 0 } } // This function gives you the point at which you must start braking (at the rate of -acceleration) if // you started at speed initial_rate and accelerated until this point and want to end at the final_rate after // a total travel of distance. This can be used to compute the intersection point between acceleration and // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed) FORCE_INLINE float intersection_distance(float initial_rate, float final_rate, float acceleration, float distance) { if (acceleration!=0) { return((2.0*acceleration*distance-initial_rate*initial_rate+final_rate*final_rate)/ (4.0*acceleration) ); } else { return 0.0; // acceleration was 0, set intersection distance to 0 } } // Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors. void calculate_trapezoid_for_block(block_t *block, float entry_factor, float exit_factor) { unsigned long initial_rate = ceil(block->nominal_rate*entry_factor); // (step/min) unsigned long final_rate = ceil(block->nominal_rate*exit_factor); // (step/min) // Limit minimal step rate (Otherwise the timer will overflow.) if(initial_rate <120) { initial_rate=120; } if(final_rate < 120) { final_rate=120; } long acceleration = block->acceleration_st; int32_t accelerate_steps = ceil(estimate_acceleration_distance(block->initial_rate, block->nominal_rate, acceleration)); int32_t decelerate_steps = floor(estimate_acceleration_distance(block->nominal_rate, block->final_rate, -acceleration)); // Calculate the size of Plateau of Nominal Rate. int32_t plateau_steps = block->step_event_count-accelerate_steps-decelerate_steps; // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will // have to use intersection_distance() to calculate when to abort acceleration and start braking // in order to reach the final_rate exactly at the end of this block. if (plateau_steps < 0) { accelerate_steps = ceil(intersection_distance(block->initial_rate, block->final_rate, acceleration, block->step_event_count)); accelerate_steps = max(accelerate_steps,0); // Check limits due to numerical round-off accelerate_steps = min((uint32_t)accelerate_steps,block->step_event_count);//(We can cast here to unsigned, because the above line ensures that we are above zero) plateau_steps = 0; } #ifdef ADVANCE volatile long initial_advance = block->advance*entry_factor*entry_factor; volatile long final_advance = block->advance*exit_factor*exit_factor; #endif // ADVANCE // block->accelerate_until = accelerate_steps; // block->decelerate_after = accelerate_steps+plateau_steps; CRITICAL_SECTION_START; // Fill variables used by the stepper in a critical section if(block->busy == false) { // Don't update variables if block is busy. block->accelerate_until = accelerate_steps; block->decelerate_after = accelerate_steps+plateau_steps; block->initial_rate = initial_rate; block->final_rate = final_rate; #ifdef ADVANCE block->initial_advance = initial_advance; block->final_advance = final_advance; #endif //ADVANCE } CRITICAL_SECTION_END; } // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the // acceleration within the allotted distance. FORCE_INLINE float max_allowable_speed(float acceleration, float target_velocity, float distance) { return sqrt(target_velocity*target_velocity-2*acceleration*distance); } // "Junction jerk" in this context is the immediate change in speed at the junction of two blocks. // This method will calculate the junction jerk as the euclidean distance between the nominal // velocities of the respective blocks. //inline float junction_jerk(block_t *before, block_t *after) { // return sqrt( // pow((before->speed_x-after->speed_x), 2)+pow((before->speed_y-after->speed_y), 2)); //} // The kernel called by planner_recalculate() when scanning the plan from last to first entry. void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *next) { if(!current) { return; } if (next) { // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising. // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and // check for maximum allowable speed reductions to ensure maximum possible planned speed. if (current->entry_speed != current->max_entry_speed) { // If nominal length true, max junction speed is guaranteed to be reached. Only compute // for max allowable speed if block is decelerating and nominal length is false. if ((!current->nominal_length_flag) && (current->max_entry_speed > next->entry_speed)) { current->entry_speed = min( current->max_entry_speed, max_allowable_speed(-current->acceleration,next->entry_speed,current->millimeters)); } else { current->entry_speed = current->max_entry_speed; } current->recalculate_flag = true; } } // Skip last block. Already initialized and set for recalculation. } // planner_recalculate() needs to go over the current plan twice. Once in reverse and once forward. This // implements the reverse pass. void planner_reverse_pass() { uint8_t block_index = block_buffer_head; //Make a local copy of block_buffer_tail, because the interrupt can alter it CRITICAL_SECTION_START; unsigned char tail = block_buffer_tail; CRITICAL_SECTION_END if(((block_buffer_head-tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1)) > 3) { block_index = (block_buffer_head - 3) & (BLOCK_BUFFER_SIZE - 1); block_t *block[3] = { NULL, NULL, NULL }; while(block_index != tail) { block_index = prev_block_index(block_index); block[2]= block[1]; block[1]= block[0]; block[0] = &block_buffer[block_index]; planner_reverse_pass_kernel(block[0], block[1], block[2]); } } } // The kernel called by planner_recalculate() when scanning the plan from first to last entry. void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *next) { if(!previous) { return; } // If the previous block is an acceleration block, but it is not long enough to complete the // full speed change within the block, we need to adjust the entry speed accordingly. Entry // speeds have already been reset, maximized, and reverse planned by reverse planner. // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck. if (!previous->nominal_length_flag) { if (previous->entry_speed < current->entry_speed) { double entry_speed = min( current->entry_speed, max_allowable_speed(-previous->acceleration,previous->entry_speed,previous->millimeters) ); // Check for junction speed change if (current->entry_speed != entry_speed) { current->entry_speed = entry_speed; current->recalculate_flag = true; } } } } // planner_recalculate() needs to go over the current plan twice. Once in reverse and once forward. This // implements the forward pass. void planner_forward_pass() { uint8_t block_index = block_buffer_tail; block_t *block[3] = { NULL, NULL, NULL }; while(block_index != block_buffer_head) { block[0] = block[1]; block[1] = block[2]; block[2] = &block_buffer[block_index]; planner_forward_pass_kernel(block[0],block[1],block[2]); block_index = next_block_index(block_index); } planner_forward_pass_kernel(block[1], block[2], NULL); } // Recalculates the trapezoid speed profiles for all blocks in the plan according to the // entry_factor for each junction. Must be called by planner_recalculate() after // updating the blocks. void planner_recalculate_trapezoids() { int8_t block_index = block_buffer_tail; block_t *current; block_t *next = NULL; while(block_index != block_buffer_head) { current = next; next = &block_buffer[block_index]; if (current) { // Recalculate if current block entry or exit junction speed has changed. if (current->recalculate_flag || next->recalculate_flag) { // NOTE: Entry and exit factors always > 0 by all previous logic operations. calculate_trapezoid_for_block(current, current->entry_speed/current->nominal_speed, next->entry_speed/current->nominal_speed); current->recalculate_flag = false; // Reset current only to ensure next trapezoid is computed } } block_index = next_block_index( block_index ); } // Last/newest block in buffer. Exit speed is set with MINIMUM_PLANNER_SPEED. Always recalculated. if(next != NULL) { calculate_trapezoid_for_block(next, next->entry_speed/next->nominal_speed, MINIMUM_PLANNER_SPEED/next->nominal_speed); next->recalculate_flag = false; } } // Recalculates the motion plan according to the following algorithm: // // 1. Go over every block in reverse order and calculate a junction speed reduction (i.e. block_t.entry_factor) // so that: // a. The junction jerk is within the set limit // b. No speed reduction within one block requires faster deceleration than the one, true constant // acceleration. // 2. Go over every block in chronological order and dial down junction speed reduction values if // a. The speed increase within one block would require faster accelleration than the one, true // constant acceleration. // // When these stages are complete all blocks have an entry_factor that will allow all speed changes to // be performed using only the one, true constant acceleration, and where no junction jerk is jerkier than // the set limit. Finally it will: // // 3. Recalculate trapezoids for all blocks. void planner_recalculate() { planner_reverse_pass(); planner_forward_pass(); planner_recalculate_trapezoids(); } void plan_init() { block_buffer_head = 0; block_buffer_tail = 0; memset(position, 0, sizeof(position)); // clear position previous_speed[0] = 0.0; previous_speed[1] = 0.0; previous_speed[2] = 0.0; previous_speed[3] = 0.0; previous_nominal_speed = 0.0; } #ifdef AUTOTEMP void getHighESpeed() { static float oldt=0; if(!autotemp_enabled){ return; } if(degTargetHotend0()+2<autotemp_min) { //probably temperature set to zero. return; //do nothing } float high=0.0; uint8_t block_index = block_buffer_tail; while(block_index != block_buffer_head) { if((block_buffer[block_index].steps_x != 0) || (block_buffer[block_index].steps_y != 0) || (block_buffer[block_index].steps_z != 0)) { float se=(float(block_buffer[block_index].steps_e)/float(block_buffer[block_index].step_event_count))*block_buffer[block_index].nominal_speed; //se; mm/sec; if(se>high) { high=se; } } block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1); } float g=autotemp_min+high*autotemp_factor; float t=g; if(t<autotemp_min) t=autotemp_min; if(t>autotemp_max) t=autotemp_max; if(oldt>t) { t=AUTOTEMP_OLDWEIGHT*oldt+(1-AUTOTEMP_OLDWEIGHT)*t; } oldt=t; setTargetHotend0(t); } #endif void check_axes_activity() { unsigned char x_active = 0; unsigned char y_active = 0; unsigned char z_active = 0; unsigned char e_active = 0; unsigned char tail_fan_speed = fanSpeed; #ifdef BARICUDA unsigned char tail_valve_pressure = ValvePressure; unsigned char tail_e_to_p_pressure = EtoPPressure; #endif block_t *block; if(block_buffer_tail != block_buffer_head) { uint8_t block_index = block_buffer_tail; tail_fan_speed = block_buffer[block_index].fan_speed; #ifdef BARICUDA tail_valve_pressure = block_buffer[block_index].valve_pressure; tail_e_to_p_pressure = block_buffer[block_index].e_to_p_pressure; #endif while(block_index != block_buffer_head) { block = &block_buffer[block_index]; if(block->steps_x != 0) x_active++; if(block->steps_y != 0) y_active++; if(block->steps_z != 0) z_active++; if(block->steps_e != 0) e_active++; block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1); } } if((DISABLE_X) && (x_active == 0)) disable_x(); if((DISABLE_Y) && (y_active == 0)) disable_y(); if((DISABLE_Z) && (z_active == 0)) disable_z(); if((DISABLE_E) && (e_active == 0)) { disable_e0(); disable_e1(); disable_e2(); } #if defined(FAN_PIN) && FAN_PIN > -1 #ifdef FAN_KICKSTART_TIME static unsigned long fan_kick_end; if (tail_fan_speed) { if (fan_kick_end == 0) { // Just starting up fan - run at full power. fan_kick_end = millis() + FAN_KICKSTART_TIME; tail_fan_speed = 255; } else if (fan_kick_end > millis()) // Fan still spinning up. tail_fan_speed = 255; } else { fan_kick_end = 0; } #endif//FAN_KICKSTART_TIME #ifdef FAN_SOFT_PWM fanSpeedSoftPwm = tail_fan_speed; #else analogWrite(FAN_PIN,tail_fan_speed); #endif//!FAN_SOFT_PWM #endif//FAN_PIN > -1 #ifdef AUTOTEMP getHighESpeed(); #endif #ifdef BARICUDA #if defined(HEATER_1_PIN) && HEATER_1_PIN > -1 analogWrite(HEATER_1_PIN,tail_valve_pressure); #endif #if defined(HEATER_2_PIN) && HEATER_2_PIN > -1 analogWrite(HEATER_2_PIN,tail_e_to_p_pressure); #endif #endif } float junction_deviation = 0.1; // Add a new linear movement to the buffer. steps_x, _y and _z is the absolute position in // mm. Microseconds specify how many microseconds the move should take to perform. To aid acceleration // calculation the caller must also provide the physical length of the line in millimeters. void plan_buffer_line(const float &x, const float &y, const float &z, const float &e, float feed_rate, const uint8_t &extruder) { // Calculate the buffer head after we push this byte int next_buffer_head = next_block_index(block_buffer_head); // If the buffer is full: good! That means we are well ahead of the robot. // Rest here until there is room in the buffer. while(block_buffer_tail == next_buffer_head) { manage_heater(); manage_inactivity(); lcd_update(); } // The target position of the tool in absolute steps // Calculate target position in absolute steps //this should be done after the wait, because otherwise a M92 code within the gcode disrupts this calculation somehow long target[4]; target[X_AXIS] = lround(x*axis_steps_per_unit[X_AXIS]); target[Y_AXIS] = lround(y*axis_steps_per_unit[Y_AXIS]); target[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]); target[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]); #ifdef PREVENT_DANGEROUS_EXTRUDE if(target[E_AXIS]!=position[E_AXIS]) { if(degHotend(active_extruder)<extrude_min_temp) { position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part SERIAL_ECHO_START; SERIAL_ECHOLNPGM(MSG_ERR_COLD_EXTRUDE_STOP); } #ifdef PREVENT_LENGTHY_EXTRUDE if(labs(target[E_AXIS]-position[E_AXIS])>axis_steps_per_unit[E_AXIS]*EXTRUDE_MAXLENGTH) { position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part SERIAL_ECHO_START; SERIAL_ECHOLNPGM(MSG_ERR_LONG_EXTRUDE_STOP); } #endif } #endif // Prepare to set up new block block_t *block = &block_buffer[block_buffer_head]; // Mark block as not busy (Not executed by the stepper interrupt) block->busy = false; // Number of steps for each axis #ifndef COREXY // default non-h-bot planning block->steps_x = labs(target[X_AXIS]-position[X_AXIS]); block->steps_y = labs(target[Y_AXIS]-position[Y_AXIS]); #else // corexy planning // these equations follow the form of the dA and dB equations on http://www.corexy.com/theory.html block->steps_x = labs((target[X_AXIS]-position[X_AXIS]) + (target[Y_AXIS]-position[Y_AXIS])); block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-position[Y_AXIS])); #endif block->steps_z = labs(target[Z_AXIS]-position[Z_AXIS]); block->steps_e = labs(target[E_AXIS]-position[E_AXIS]); block->steps_e *= extrudemultiply; block->steps_e /= 100; block->step_event_count = max(block->steps_x, max(block->steps_y, max(block->steps_z, block->steps_e))); // Bail if this is a zero-length block if (block->step_event_count <= dropsegments) { return; } block->fan_speed = fanSpeed; #ifdef BARICUDA block->valve_pressure = ValvePressure; block->e_to_p_pressure = EtoPPressure; #endif // Compute direction bits for this block block->direction_bits = 0; #ifndef COREXY if (target[X_AXIS] < position[X_AXIS]) { block->direction_bits |= (1<<X_AXIS); } if (target[Y_AXIS] < position[Y_AXIS]) { block->direction_bits |= (1<<Y_AXIS); } #else if ((target[X_AXIS]-position[X_AXIS]) + (target[Y_AXIS]-position[Y_AXIS]) < 0) { block->direction_bits |= (1<<X_AXIS); } if ((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-position[Y_AXIS]) < 0) { block->direction_bits |= (1<<Y_AXIS); } #endif if (target[Z_AXIS] < position[Z_AXIS]) { block->direction_bits |= (1<<Z_AXIS); } if (target[E_AXIS] < position[E_AXIS]) { block->direction_bits |= (1<<E_AXIS); } block->active_extruder = extruder; //enable active axes #ifdef COREXY if((block->steps_x != 0) || (block->steps_y != 0)) { enable_x(); enable_y(); } #else if(block->steps_x != 0) enable_x(); if(block->steps_y != 0) enable_y(); #endif #ifndef Z_LATE_ENABLE if(block->steps_z != 0) enable_z(); #endif // Enable all if(block->steps_e != 0) { enable_e0(); enable_e1(); enable_e2(); } if (block->steps_e == 0) { if(feed_rate<mintravelfeedrate) feed_rate=mintravelfeedrate; } else { if(feed_rate<minimumfeedrate) feed_rate=minimumfeedrate; } float delta_mm[4]; #ifndef COREXY delta_mm[X_AXIS] = (target[X_AXIS]-position[X_AXIS])/axis_steps_per_unit[X_AXIS]; delta_mm[Y_AXIS] = (target[Y_AXIS]-position[Y_AXIS])/axis_steps_per_unit[Y_AXIS]; #else delta_mm[X_AXIS] = ((target[X_AXIS]-position[X_AXIS]) + (target[Y_AXIS]-position[Y_AXIS]))/axis_steps_per_unit[X_AXIS]; delta_mm[Y_AXIS] = ((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-position[Y_AXIS]))/axis_steps_per_unit[Y_AXIS]; #endif delta_mm[Z_AXIS] = (target[Z_AXIS]-position[Z_AXIS])/axis_steps_per_unit[Z_AXIS]; delta_mm[E_AXIS] = ((target[E_AXIS]-position[E_AXIS])/axis_steps_per_unit[E_AXIS])*extrudemultiply/100.0; if ( block->steps_x <=dropsegments && block->steps_y <=dropsegments && block->steps_z <=dropsegments ) { block->millimeters = fabs(delta_mm[E_AXIS]); } else { block->millimeters = sqrt(square(delta_mm[X_AXIS]) + square(delta_mm[Y_AXIS]) + square(delta_mm[Z_AXIS])); } float inverse_millimeters = 1.0/block->millimeters; // Inverse millimeters to remove multiple divides // Calculate speed in mm/second for each axis. No divide by zero due to previous checks. float inverse_second = feed_rate * inverse_millimeters; int moves_queued=(block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1); // slow down when de buffer starts to empty, rather than wait at the corner for a buffer refill #ifdef OLD_SLOWDOWN if(moves_queued < (BLOCK_BUFFER_SIZE * 0.5) && moves_queued > 1) feed_rate = feed_rate*moves_queued / (BLOCK_BUFFER_SIZE * 0.5); #endif #ifdef SLOWDOWN // segment time im micro seconds unsigned long segment_time = lround(1000000.0/inverse_second); if ((moves_queued > 1) && (moves_queued < (BLOCK_BUFFER_SIZE * 0.5))) { if (segment_time < minsegmenttime) { // buffer is draining, add extra time. The amount of time added increases if the buffer is still emptied more. inverse_second=1000000.0/(segment_time+lround(2*(minsegmenttime-segment_time)/moves_queued)); #ifdef XY_FREQUENCY_LIMIT segment_time = lround(1000000.0/inverse_second); #endif } } #endif // END OF SLOW DOWN SECTION block->nominal_speed = block->millimeters * inverse_second; // (mm/sec) Always > 0 block->nominal_rate = ceil(block->step_event_count * inverse_second); // (step/sec) Always > 0 // Calculate and limit speed in mm/sec for each axis float current_speed[4]; float speed_factor = 1.0; //factor <=1 do decrease speed for(int i=0; i < 4; i++) { current_speed[i] = delta_mm[i] * inverse_second; if(fabs(current_speed[i]) > max_feedrate[i]) speed_factor = min(speed_factor, max_feedrate[i] / fabs(current_speed[i])); } // Max segement time in us. #ifdef XY_FREQUENCY_LIMIT #define MAX_FREQ_TIME (1000000.0/XY_FREQUENCY_LIMIT) // Check and limit the xy direction change frequency unsigned char direction_change = block->direction_bits ^ old_direction_bits; old_direction_bits = block->direction_bits; segment_time = lround((float)segment_time / speed_factor); if((direction_change & (1<<X_AXIS)) == 0) { x_segment_time[0] += segment_time; } else { x_segment_time[2] = x_segment_time[1]; x_segment_time[1] = x_segment_time[0]; x_segment_time[0] = segment_time; } if((direction_change & (1<<Y_AXIS)) == 0) { y_segment_time[0] += segment_time; } else { y_segment_time[2] = y_segment_time[1]; y_segment_time[1] = y_segment_time[0]; y_segment_time[0] = segment_time; } long max_x_segment_time = max(x_segment_time[0], max(x_segment_time[1], x_segment_time[2])); long max_y_segment_time = max(y_segment_time[0], max(y_segment_time[1], y_segment_time[2])); long min_xy_segment_time =min(max_x_segment_time, max_y_segment_time); if(min_xy_segment_time < MAX_FREQ_TIME) speed_factor = min(speed_factor, speed_factor * (float)min_xy_segment_time / (float)MAX_FREQ_TIME); #endif // Correct the speed if( speed_factor < 1.0) { for(unsigned char i=0; i < 4; i++) { current_speed[i] *= speed_factor; } block->nominal_speed *= speed_factor; block->nominal_rate *= speed_factor; } // Compute and limit the acceleration rate for the trapezoid generator. float steps_per_mm = block->step_event_count/block->millimeters; if(block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0) { block->acceleration_st = ceil(retract_acceleration * steps_per_mm); // convert to: acceleration steps/sec^2 } else { block->acceleration_st = ceil(acceleration * steps_per_mm); // convert to: acceleration steps/sec^2 // Limit acceleration per axis if(((float)block->acceleration_st * (float)block->steps_x / (float)block->step_event_count) > axis_steps_per_sqr_second[X_AXIS]) block->acceleration_st = axis_steps_per_sqr_second[X_AXIS]; if(((float)block->acceleration_st * (float)block->steps_y / (float)block->step_event_count) > axis_steps_per_sqr_second[Y_AXIS]) block->acceleration_st = axis_steps_per_sqr_second[Y_AXIS]; if(((float)block->acceleration_st * (float)block->steps_e / (float)block->step_event_count) > axis_steps_per_sqr_second[E_AXIS]) block->acceleration_st = axis_steps_per_sqr_second[E_AXIS]; if(((float)block->acceleration_st * (float)block->steps_z / (float)block->step_event_count ) > axis_steps_per_sqr_second[Z_AXIS]) block->acceleration_st = axis_steps_per_sqr_second[Z_AXIS]; } block->acceleration = block->acceleration_st / steps_per_mm; block->acceleration_rate = (long)((float)block->acceleration_st * (16777216.0 / (F_CPU / 8.0))); #if 0 // Use old jerk for now // Compute path unit vector double unit_vec[3]; 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, // colinear 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 // 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)) { // 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] ; // 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. vmax_junction = min(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_xy_jerk/2; float vmax_junction_factor = 1.0; if(fabs(current_speed[Z_AXIS]) > max_z_jerk/2) vmax_junction = min(vmax_junction, max_z_jerk/2); if(fabs(current_speed[E_AXIS]) > max_e_jerk/2) vmax_junction = min(vmax_junction, max_e_jerk/2); vmax_junction = min(vmax_junction, block->nominal_speed); float safe_speed = vmax_junction; if ((moves_queued > 1) && (previous_nominal_speed > 0.0001)) { float jerk = sqrt(pow((current_speed[X_AXIS]-previous_speed[X_AXIS]), 2)+pow((current_speed[Y_AXIS]-previous_speed[Y_AXIS]), 2)); // if((fabs(previous_speed[X_AXIS]) > 0.0001) || (fabs(previous_speed[Y_AXIS]) > 0.0001)) { vmax_junction = block->nominal_speed; // } if (jerk > max_xy_jerk) { vmax_junction_factor = (max_xy_jerk/jerk); } if(fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]) > max_z_jerk) { vmax_junction_factor= min(vmax_junction_factor, (max_z_jerk/fabs(current_speed[Z_AXIS] - previous_speed[Z_AXIS]))); } if(fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]) > max_e_jerk) { vmax_junction_factor = min(vmax_junction_factor, (max_e_jerk/fabs(current_speed[E_AXIS] - previous_speed[E_AXIS]))); } vmax_junction = min(previous_nominal_speed, vmax_junction * vmax_junction_factor); // Limit speed to max previous speed } block->max_entry_speed = vmax_junction; // Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED. double v_allowable = max_allowable_speed(-block->acceleration,MINIMUM_PLANNER_SPEED,block->millimeters); block->entry_speed = min(vmax_junction, v_allowable); // Initialize planner efficiency flags // Set flag if block will always reach maximum junction speed regardless of entry/exit speeds. // If a block can de/ac-celerate from nominal speed to zero within the length of the block, then // the current block and next block junction speeds are guaranteed to always be at their maximum // junction speeds in deceleration and acceleration, respectively. This is due to how the current // 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. if (block->nominal_speed <= v_allowable) { block->nominal_length_flag = true; } else { block->nominal_length_flag = false; } block->recalculate_flag = true; // Always calculate trapezoid for new block // Update previous path unit_vector and nominal speed memcpy(previous_speed, current_speed, sizeof(previous_speed)); // previous_speed[] = current_speed[] previous_nominal_speed = block->nominal_speed; #ifdef ADVANCE // Calculate advance rate if((block->steps_e == 0) || (block->steps_x == 0 && block->steps_y == 0 && block->steps_z == 0)) { block->advance_rate = 0; block->advance = 0; } else { long acc_dist = estimate_acceleration_distance(0, block->nominal_rate, block->acceleration_st); float advance = (STEPS_PER_CUBIC_MM_E * EXTRUDER_ADVANCE_K) * (current_speed[E_AXIS] * current_speed[E_AXIS] * EXTRUTION_AREA * EXTRUTION_AREA)*256; block->advance = advance; if(acc_dist == 0) { block->advance_rate = 0; } else { block->advance_rate = advance / (float)acc_dist; } } /* SERIAL_ECHO_START; SERIAL_ECHOPGM("advance :"); SERIAL_ECHO(block->advance/256.0); SERIAL_ECHOPGM("advance rate :"); SERIAL_ECHOLN(block->advance_rate/256.0); */ #endif // ADVANCE calculate_trapezoid_for_block(block, block->entry_speed/block->nominal_speed, safe_speed/block->nominal_speed); // Move buffer head block_buffer_head = next_buffer_head; // Update position memcpy(position, target, sizeof(target)); // position[] = target[] planner_recalculate(); st_wake_up(); } void plan_set_position(const float &x, const float &y, const float &z, const float &e) { position[X_AXIS] = lround(x*axis_steps_per_unit[X_AXIS]); position[Y_AXIS] = lround(y*axis_steps_per_unit[Y_AXIS]); position[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]); position[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]); st_set_position(position[X_AXIS], position[Y_AXIS], position[Z_AXIS], position[E_AXIS]); previous_nominal_speed = 0.0; // Resets planner junction speeds. Assumes start from rest. previous_speed[0] = 0.0; previous_speed[1] = 0.0; previous_speed[2] = 0.0; previous_speed[3] = 0.0; } void plan_set_e_position(const float &e) { position[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]); st_set_e_position(position[E_AXIS]); } uint8_t movesplanned() { return (block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1); } #ifdef PREVENT_DANGEROUS_EXTRUDE void set_extrude_min_temp(float temp) { extrude_min_temp=temp; } #endif // Calculate the steps/s^2 acceleration rates, based on the mm/s^s void reset_acceleration_rates() { for(int8_t i=0; i < NUM_AXIS; i++) { axis_steps_per_sqr_second[i] = max_acceleration_units_per_sq_second[i] * axis_steps_per_unit[i]; } }
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