src/modules/robot/Block.cpp

   1 /*
   2       This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl).
   3       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.
   4       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.
   5       You should have received a copy of the GNU General Public License along with Smoothie. If not, see <http://www.gnu.org/licenses/>.
   6 */
   7
   8 #include "libs/Module.h"
   9 #include "libs/Kernel.h"
  10 #include "libs/nuts_bolts.h"
  11 #include <math.h>
  12 #include <string>
  13 #include "Block.h"
  14 #include "Planner.h"
  15 #include "Player.h"
  16 using std::string;
  17 #include <vector>
  18 #include "../communication/utils/Gcode.h"
  19
  20 Block::Block(){
  21     clear_vector(this->steps);
  22     this->times_taken = 0;   // A block can be "taken" by any number of modules, and the next block is not moved to until all the modules have "released" it. This value serves as a tracker.
  23     this->is_ready = false;
  24     this->initial_rate = -1;
  25     this->final_rate = -1;
  26 }
  27
  28 void Block::debug(Kernel* kernel){
  29     kernel->serial->printf("%p: steps:%4d|%4d|%4d(max:%4d) nominal:r%10d/s%6.1f mm:%9.6f rdelta:%8d acc:%5d dec:%5d rates:%10d>%10d taken:%d ready:%d \r\n", this, this->steps[0], this->steps[1], this->steps[2], this->steps_event_count, this->nominal_rate, this->nominal_speed, this->millimeters, this->rate_delta, this->accelerate_until, this->decelerate_after, this->initial_rate, this->final_rate, this->times_taken, this->is_ready );
  30 }
  31
  32
  33 // Calculate a braking factor to reach baseline speed which is max_jerk/2, e.g. the
  34 // speed under which you cannot exceed max_jerk no matter what you do.
  35 double Block::compute_factor_for_safe_speed(){
  36     return( this->planner->max_jerk / this->nominal_speed );
  37 }
  38
  39
  40 // Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
  41 // The factors represent a factor of braking and must be in the range 0.0-1.0.
  42 //                                +--------+ <- nominal_rate
  43 //                               /          \
  44 // nominal_rate*entry_factor -> +            \
  45 //                              |             + <- nominal_rate*exit_factor
  46 //                              +-------------+
  47 //                                  time -->
  48 void Block::calculate_trapezoid( double entryfactor, double exitfactor ){
  49
  50     this->initial_rate = ceil(this->nominal_rate * entryfactor);   // (step/min)
  51     this->final_rate   = ceil(this->nominal_rate * exitfactor);    // (step/min)
  52     double acceleration_per_minute = this->rate_delta * this->planner->kernel->stepper->acceleration_ticks_per_second * 60.0;
  53     int accelerate_steps = ceil( this->estimate_acceleration_distance( this->initial_rate, this->nominal_rate, acceleration_per_minute ) );
  54     int decelerate_steps = ceil( this->estimate_acceleration_distance( this->nominal_rate, this->final_rate,  -acceleration_per_minute ) );
  55
  56     // Calculate the size of Plateau of Nominal Rate.
  57     int plateau_steps = this->steps_event_count-accelerate_steps-decelerate_steps;
  58
  59    // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will
  60    // have to use intersection_distance() to calculate when to abort acceleration and start braking
  61    // in order to reach the final_rate exactly at the end of this block.
  62    if (plateau_steps < 0) {
  63        accelerate_steps = ceil(this->intersection_distance(this->initial_rate, this->final_rate, acceleration_per_minute, this->steps_event_count));
  64        accelerate_steps = max( accelerate_steps, 0 ); // Check limits due to numerical round-off
  65        accelerate_steps = min( accelerate_steps, int(this->steps_event_count) );
  66        plateau_steps = 0;
  67    }
  68
  69    this->accelerate_until = accelerate_steps;
  70    this->decelerate_after = accelerate_steps+plateau_steps;
  71
  72    // TODO: FIX THIS: DIRTY HACK so that we don't end too early for blocks with 0 as final_rate. Doing the math right would be better. Probably fixed in latest grbl
  73    if( this->final_rate < 0.01 ){
  74         this->decelerate_after += floor( this->nominal_rate / 60 / this->planner->kernel->stepper->acceleration_ticks_per_second ) * 3;
  75     }
  76
  77 }
  78
  79 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
  80 // given acceleration:
  81 double Block::estimate_acceleration_distance(double initialrate, double targetrate, double acceleration) {
  82       return( (targetrate*targetrate-initialrate*initialrate)/(2L*acceleration));
  83 }
  84
  85 // This function gives you the point at which you must start braking (at the rate of -acceleration) if
  86 // you started at speed initial_rate and accelerated until this point and want to end at the final_rate after
  87 // a total travel of distance. This can be used to compute the intersection point between acceleration and
  88 // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)
  89 //
  90 /*                          + <- some maximum rate we don't care about
  91                            /|\
  92                           / | \
  93                          /  |  + <- final_rate
  94                         /   |  |
  95        initial_rate -> +----+--+
  96                             ^ ^
  97                             | |
  98         intersection_distance distance */
  99 double Block::intersection_distance(double initialrate, double finalrate, double acceleration, double distance) {
 100    return((2*acceleration*distance-initialrate*initialrate+finalrate*finalrate)/(4*acceleration));
 101 }
 102
 103 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
 104 // acceleration within the allotted distance.
 105 inline double max_allowable_speed(double acceleration, double target_velocity, double distance) {
 106   return(
 107     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
 108   );
 109 }
 110
 111
 112 // Called by Planner::recalculate() when scanning the plan from last to first entry.
 113 void Block::reverse_pass(Block* next, Block* previous){
 114
 115     if (next) {
 116         // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
 117         // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
 118         // check for maximum allowable speed reductions to ensure maximum possible planned speed.
 119         if (this->entry_speed != this->max_entry_speed) {
 120
 121             // If nominal length true, max junction speed is guaranteed to be reached. Only compute
 122             // for max allowable speed if block is decelerating and nominal length is false.
 123             if ((!this->nominal_length_flag) && (this->max_entry_speed > next->entry_speed)) {
 124                 this->entry_speed = min( this->max_entry_speed, max_allowable_speed(-this->planner->acceleration,next->entry_speed,this->millimeters));
 125             } else {
 126                 this->entry_speed = this->max_entry_speed;
 127             }
 128             this->recalculate_flag = true;
 129
 130         }
 131     } // Skip last block. Already initialized and set for recalculation.
 132
 133 }
 134
 135
 136 // Called by Planner::recalculate() when scanning the plan from first to last entry.
 137 void Block::forward_pass(Block* previous, Block* next){
 138
 139     if(!previous) { return; } // Begin planning after buffer_tail
 140
 141     // If the previous block is an acceleration block, but it is not long enough to complete the
 142     // full speed change within the block, we need to adjust the entry speed accordingly. Entry
 143     // speeds have already been reset, maximized, and reverse planned by reverse planner.
 144     // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
 145     if (!previous->nominal_length_flag) {
 146         if (previous->entry_speed < this->entry_speed) {
 147           double entry_speed = min( this->entry_speed,
 148             max_allowable_speed(-this->planner->acceleration,previous->entry_speed,previous->millimeters) );
 149
 150           // Check for junction speed change
 151           if (this->entry_speed != entry_speed) {
 152             this->entry_speed = entry_speed;
 153             this->recalculate_flag = true;
 154           }
 155         }
 156     }
 157
 158 }
 159
 160
 161 // Gcodes are attached to their respective blocks so that on_gcode_execute can be called with it
 162 void Block::append_gcode(Gcode* gcode){
 163    __disable_irq();
 164    this->gcodes.push_back(*gcode);
 165    __enable_irq();
 166 }
 167
 168 // The attached gcodes are then poped and the on_gcode_execute event is called with them as a parameter
 169 void Block::pop_and_execute_gcode(Kernel* &kernel){
 170     Block* block = const_cast<Block*>(this);
 171     for(unsigned short index=0; index<block->gcodes.size(); index++){
 172         kernel->call_event(ON_GCODE_EXECUTE, &(block->gcodes[index]));
 173     }
 174 }
 175
 176 // Signal the player that this block is ready to be injected into the system
 177 void Block::ready(){
 178     this->is_ready = true;
 179     this->player->new_block_added();
 180 }
 181
 182 // Mark the block as taken by one more module
 183 void Block::take(){
 184     this->times_taken++;
 185 }
 186
 187 // Mark the block as no longer taken by one module, go to next block if this free's it
 188 void Block::release(){
 189     this->times_taken--;
 190     if( this->times_taken < 1 ){
 191         this->player->kernel->call_event(ON_BLOCK_END, this);
 192         this->pop_and_execute_gcode(this->player->kernel);
 193         Player* player = this->player;
 194
 195         if( player->queue.size() > 0 ){
 196             player->queue.delete_first();
 197         }
 198
 199         if( player->looking_for_new_block == false ){
 200             if( player->queue.size() > 0 ){
 201                 Block* candidate =  player->queue.get_ref(0);
 202                 if( candidate->is_ready ){
 203                     player->current_block = candidate;
 204                     player->kernel->call_event(ON_BLOCK_BEGIN, player->current_block);
 205                     if( player->current_block->times_taken < 1 ){
 206                         player->current_block->release();
 207                     }
 208                 }else{
 209
 210                     player->current_block = NULL;
 211
 212                 }
 213             }else{
 214                 player->current_block = NULL;
 215             }
 216         }
 217     }
 218 }
 219
 220
 221