smoothie port to mbed online compiler (smoothieware.org)
For documentation, license, ..., please check http://smoothieware.org/
This version has been tested with a 3 axis machine
Diff: modules/robot/Planner.cpp
- Revision:
- 0:31e91bb0ef3c
diff -r 000000000000 -r 31e91bb0ef3c modules/robot/Planner.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/modules/robot/Planner.cpp Tue Jul 31 21:11:18 2012 +0000 @@ -0,0 +1,264 @@ +/* + This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl) with additions from Sungeun K. Jeon (https://github.com/chamnit/grbl) + Smoothie 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. + Smoothie 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 Smoothie. If not, see <http://www.gnu.org/licenses/>. +*/ + +using namespace std; +#include <vector> +#include "libs/nuts_bolts.h" +#include "libs/RingBuffer.h" +#include "../communication/utils/Gcode.h" +#include "libs/Module.h" +#include "libs/Kernel.h" +#include "Block.h" +#include "Planner.h" +#include "Player.h" + + +Planner::Planner(){ + clear_vector(this->position); + clear_vector_double(this->previous_unit_vec); + this->previous_nominal_speed = 0.0; + this->has_deleted_block = false; +} + +void Planner::on_module_loaded(){ + this->on_config_reload(this); +} + +void Planner::on_config_reload(void* argument){ + this->acceleration = this->kernel->config->value(acceleration_checksum )->by_default(100 )->as_number(); + this->max_jerk = this->kernel->config->value(max_jerk_checksum )->by_default(100 )->as_number(); + this->junction_deviation = this->kernel->config->value(junction_deviation_checksum )->by_default(0.05)->as_number(); +} + + +// Append a block to the queue, compute it's speed factors +void Planner::append_block( int target[], double feed_rate, double distance, double deltas[] ){ + + // Stall here if the queue is ful + this->kernel->player->wait_for_queue(2); + + Block* block = this->kernel->player->new_block(); + block->planner = this; + + // Direction bits + block->direction_bits = 0; + for( int stepper=ALPHA_STEPPER; stepper<=GAMMA_STEPPER; stepper++){ + if( target[stepper] < position[stepper] ){ block->direction_bits |= (1<<stepper); } + } + + // Number of steps for each stepper + for( int stepper=ALPHA_STEPPER; stepper<=GAMMA_STEPPER; stepper++){ block->steps[stepper] = labs(target[stepper] - this->position[stepper]); } + + // Max number of steps, for all axes + block->steps_event_count = max( block->steps[ALPHA_STEPPER], max( block->steps[BETA_STEPPER], block->steps[GAMMA_STEPPER] ) ); + //if( block->steps_event_count == 0 ){ this->computing = false; return; } + + block->millimeters = distance; + double inverse_millimeters = 0; + if( distance > 0 ){ inverse_millimeters = 1.0/distance; } + + // Calculate speed in mm/minute for each axis. No divide by zero due to previous checks. + // NOTE: Minimum stepper speed is limited by MINIMUM_STEPS_PER_MINUTE in stepper.c + double inverse_minute = feed_rate * inverse_millimeters; + if( distance > 0 ){ + block->nominal_speed = block->millimeters * inverse_minute; // (mm/min) Always > 0 + block->nominal_rate = ceil(block->steps_event_count * inverse_minute); // (step/min) Always > 0 + }else{ + block->nominal_speed = 0; + block->nominal_rate = 0; + } + + //this->kernel->serial->printf("nom_speed: %f nom_rate: %u step_event_count: %u block->steps_z: %u \r\n", block->nominal_speed, block->nominal_rate, block->steps_event_count, block->steps[2] ); + + // Compute the acceleration rate for the trapezoid generator. Depending on the slope of the line + // average travel per step event changes. For a line along one axis the travel per step event + // is equal to the travel/step in the particular axis. For a 45 degree line the steppers of both + // axes might step for every step event. Travel per step event is then sqrt(travel_x^2+travel_y^2). + // To generate trapezoids with contant acceleration between blocks the rate_delta must be computed + // specifically for each line to compensate for this phenomenon: + // Convert universal acceleration for direction-dependent stepper rate change parameter + block->rate_delta = ceil( block->steps_event_count*inverse_millimeters * this->acceleration*60.0 / this->kernel->stepper->acceleration_ticks_per_second ); // (step/min/acceleration_tick) + + // Compute path unit vector + double unit_vec[3]; + unit_vec[X_AXIS] = deltas[X_AXIS]*inverse_millimeters; + unit_vec[Y_AXIS] = deltas[Y_AXIS]*inverse_millimeters; + unit_vec[Z_AXIS] = deltas[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 + + if (this->kernel->player->queue.size() > 1 && (this->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 = - this->previous_unit_vec[X_AXIS] * unit_vec[X_AXIS] + - this->previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS] + - this->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(this->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(this->acceleration*60*60 * this->junction_deviation * sin_theta_d2/(1.0-sin_theta_d2)) ); + } + } + } + block->max_entry_speed = vmax_junction; + + // Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED. + double v_allowable = this->max_allowable_speed(-this->acceleration,0.0,block->millimeters); //TODO: Get from config + 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(this->previous_unit_vec, unit_vec, sizeof(unit_vec)); // previous_unit_vec[] = unit_vec[] + this->previous_nominal_speed = block->nominal_speed; + + // Update current position + memcpy(this->position, target, sizeof(int)*3); + + // Math-heavy re-computing of the whole queue to take the new + this->recalculate(); + + // The block can now be used + block->ready(); + +} + + +// 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() { + //this->kernel->serial->printf("recalculate last: %p, queue size: %d \r\n", this->kernel->player->queue.get_ref( this->kernel->player->queue.size()-1 ), this->kernel->player->queue.size() ); + this->reverse_pass(); + this->forward_pass(); + this->recalculate_trapezoids(); +} + +// 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(){ + // For each block + int block_index = this->kernel->player->queue.tail; + Block* blocks[3] = {NULL,NULL,NULL}; + + while(block_index!=this->kernel->player->queue.head){ + block_index = this->kernel->player->queue.prev_block_index( block_index ); + blocks[2] = blocks[1]; + blocks[1] = blocks[0]; + blocks[0] = &this->kernel->player->queue.buffer[block_index]; + if( blocks[1] == NULL ){ continue; } + blocks[1]->reverse_pass(blocks[2], blocks[0]); + } + +} + +// 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() { + // For each block + int block_index = this->kernel->player->queue.head; + Block* blocks[3] = {NULL,NULL,NULL}; + + while(block_index!=this->kernel->player->queue.tail){ + blocks[0] = blocks[1]; + blocks[1] = blocks[2]; + blocks[2] = &this->kernel->player->queue.buffer[block_index]; + if( blocks[0] == NULL ){ continue; } + blocks[1]->forward_pass(blocks[0],blocks[2]); + block_index = this->kernel->player->queue.next_block_index( block_index ); + } + blocks[2]->forward_pass(blocks[1],NULL); + +} + +// Recalculates the trapezoid speed profiles for flagged blocks in the plan according to the +// entry_speed for each junction and the entry_speed of the next junction. Must be called by +// planner_recalculate() after updating the blocks. Any recalulate flagged junction will +// compute the two adjacent trapezoids to the junction, since the junction speed corresponds +// to exit speed and entry speed of one another. +void Planner::recalculate_trapezoids() { + int block_index = this->kernel->player->queue.head; + Block* current; + Block* next = NULL; + + while(block_index != this->kernel->player->queue.tail){ + current = next; + next = &this->kernel->player->queue.buffer[block_index]; + //this->kernel->serial->printf("index:%d current:%p next:%p \r\n", block_index, current, next ); + if( current ){ + // Recalculate if current block entry or exit junction speed has changed. + if( current->recalculate_flag || next->recalculate_flag ){ + current->calculate_trapezoid( current->entry_speed/current->nominal_speed, next->entry_speed/current->nominal_speed ); + current->recalculate_flag = false; + } + } + block_index = this->kernel->player->queue.next_block_index( block_index ); + } + + // Last/newest block in buffer. Exit speed is set with MINIMUM_PLANNER_SPEED. Always recalculated. + next->calculate_trapezoid( next->entry_speed/next->nominal_speed, MINIMUM_PLANNER_SPEED/next->nominal_speed); //TODO: Make configuration option + next->recalculate_flag = false; + +} + +// Debug function +void Planner::dump_queue(){ + for( int index = 0; index <= this->kernel->player->queue.size()-1; index++ ){ + if( index > 10 && index < this->kernel->player->queue.size()-10 ){ continue; } + this->kernel->serial->printf("block %03d > ", index); + this->kernel->player->queue.get_ref(index)->debug(this->kernel); + } +} + +// Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the +// acceleration within the allotted distance. +double Planner::max_allowable_speed(double acceleration, double target_velocity, double distance) { + return( + sqrt(target_velocity*target_velocity-2L*acceleration*60*60*distance) //Was acceleration*60*60*distance, in case this breaks, but here we prefer to use seconds instead of minutes + ); +} + +