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->streams->printf("%p: steps:%4d|%4d|%4d(max:%4d) nominal:r%10d/s%6.1f mm:%9.6f rdelta:%8f 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->player->kernel->streams->printf("%p calculating trapezoid\r\n", this);
  51
  52     this->initial_rate = ceil(this->nominal_rate * entryfactor);   // (step/min)
  53     this->final_rate   = ceil(this->nominal_rate * exitfactor);    // (step/min)
  54
  55     //this->player->kernel->streams->printf("initrate:%f finalrate:%f\r\n", this->initial_rate, this->final_rate);
  56
  57     double acceleration_per_minute = this->rate_delta * this->planner->kernel->stepper->acceleration_ticks_per_second * 60.0; // ( step/min^2)
  58     int accelerate_steps = ceil( this->estimate_acceleration_distance( this->initial_rate, this->nominal_rate, acceleration_per_minute ) );
  59     int decelerate_steps = floor( this->estimate_acceleration_distance( this->nominal_rate, this->final_rate,  -acceleration_per_minute ) );
  60
  61
  62     // Calculate the size of Plateau of Nominal Rate.
  63     int plateau_steps = this->steps_event_count-accelerate_steps-decelerate_steps;
  64
  65     //this->player->kernel->streams->printf("accelperminute:%f accelerate_steps:%d decelerate_steps:%d plateau:%d \r\n", acceleration_per_minute, accelerate_steps, decelerate_steps, plateau_steps );
  66
  67    // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will
  68    // have to use intersection_distance() to calculate when to abort acceleration and start braking
  69    // in order to reach the final_rate exactly at the end of this block.
  70    if (plateau_steps < 0) {
  71        accelerate_steps = ceil(this->intersection_distance(this->initial_rate, this->final_rate, acceleration_per_minute, this->steps_event_count));
  72        accelerate_steps = max( accelerate_steps, 0 ); // Check limits due to numerical round-off
  73        accelerate_steps = min( accelerate_steps, int(this->steps_event_count) );
  74        plateau_steps = 0;
  75    }
  76
  77    this->accelerate_until = accelerate_steps;
  78    this->decelerate_after = accelerate_steps+plateau_steps;
  79
  80    //this->debug(this->player->kernel);
  81
  82    /*
  83    // 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
  84    if( this->final_rate < 0.01 ){
  85         this->decelerate_after += floor( this->nominal_rate / 60 / this->planner->kernel->stepper->acceleration_ticks_per_second ) * 3;
  86     }
  87     */
  88 }
  89
  90 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
  91 // given acceleration:
  92 double Block::estimate_acceleration_distance(double initialrate, double targetrate, double acceleration) {
  93       return( ((targetrate*targetrate)-(initialrate*initialrate))/(2L*acceleration));
  94 }
  95
  96 // This function gives you the point at which you must start braking (at the rate of -acceleration) if
  97 // you started at speed initial_rate and accelerated until this point and want to end at the final_rate after
  98 // a total travel of distance. This can be used to compute the intersection point between acceleration and
  99 // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)
 100 //
 101 /*                          + <- some maximum rate we don't care about
 102                            /|\
 103                           / | \
 104                          /  |  + <- final_rate
 105                         /   |  |
 106        initial_rate -> +----+--+
 107                             ^ ^
 108                             | |
 109         intersection_distance distance */
 110 double Block::intersection_distance(double initialrate, double finalrate, double acceleration, double distance) {
 111    return((2*acceleration*distance-initialrate*initialrate+finalrate*finalrate)/(4*acceleration));
 112 }
 113
 114 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
 115 // acceleration within the allotted distance.
 116 inline double max_allowable_speed(double acceleration, double target_velocity, double distance) {
 117   return(
 118     sqrt(target_velocity*target_velocity-2L*acceleration*distance)  //Was acceleration*60*60*distance, in case this breaks, but here we prefer to use seconds instead of minutes
 119   );
 120 }
 121
 122
 123 // Called by Planner::recalculate() when scanning the plan from last to first entry.
 124 void Block::reverse_pass(Block* next, Block* previous){
 125
 126     if (next) {
 127         // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
 128         // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
 129         // check for maximum allowable speed reductions to ensure maximum possible planned speed.
 130         if (this->entry_speed != this->max_entry_speed) {
 131
 132             // If nominal length true, max junction speed is guaranteed to be reached. Only compute
 133             // for max allowable speed if block is decelerating and nominal length is false.
 134             if ((!this->nominal_length_flag) && (this->max_entry_speed > next->entry_speed)) {
 135                 this->entry_speed = min( this->max_entry_speed, max_allowable_speed(-this->planner->acceleration,next->entry_speed,this->millimeters));
 136             } else {
 137                 this->entry_speed = this->max_entry_speed;
 138             }
 139             this->recalculate_flag = true;
 140
 141         }
 142     } // Skip last block. Already initialized and set for recalculation.
 143
 144 }
 145
 146
 147 // Called by Planner::recalculate() when scanning the plan from first to last entry.
 148 void Block::forward_pass(Block* previous, Block* next){
 149
 150     if(!previous) { return; } // Begin planning after buffer_tail
 151
 152     // If the previous block is an acceleration block, but it is not long enough to complete the
 153     // full speed change within the block, we need to adjust the entry speed accordingly. Entry
 154     // speeds have already been reset, maximized, and reverse planned by reverse planner.
 155     // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
 156     if (!previous->nominal_length_flag) {
 157         if (previous->entry_speed < this->entry_speed) {
 158           double entry_speed = min( this->entry_speed,
 159             max_allowable_speed(-this->planner->acceleration,previous->entry_speed,previous->millimeters) );
 160
 161           // Check for junction speed change
 162           if (this->entry_speed != entry_speed) {
 163             this->entry_speed = entry_speed;
 164             this->recalculate_flag = true;
 165           }
 166         }
 167     }
 168
 169 }
 170
 171
 172 // Gcodes are attached to their respective blocks so that on_gcode_execute can be called with it
 173 void Block::append_gcode(Gcode* gcode){
 174    __disable_irq();
 175    this->gcodes.push_back(*gcode);
 176    __enable_irq();
 177 }
 178
 179 // The attached gcodes are then poped and the on_gcode_execute event is called with them as a parameter
 180 void Block::pop_and_execute_gcode(Kernel* &kernel){
 181     Block* block = const_cast<Block*>(this);
 182     for(unsigned short index=0; index<block->gcodes.size(); index++){
 183         //printf("GCODE Z: %s \r\n", block->gcodes[index].command.c_str() );
 184         kernel->call_event(ON_GCODE_EXECUTE, &(block->gcodes[index]));
 185     }
 186 }
 187
 188 // Signal the player that this block is ready to be injected into the system
 189 void Block::ready(){
 190     this->is_ready = true;
 191     this->player->new_block_added();
 192 }
 193
 194 // Mark the block as taken by one more module
 195 void Block::take(){
 196     this->times_taken++;
 197     //printf("taking %p times now:%d\r\n", this, int(this->times_taken) );
 198 }
 199
 200 // Mark the block as no longer taken by one module, go to next block if this free's it
 201 void Block::release(){
 202     //printf("release %p \r\n", this );
 203     this->times_taken--;
 204     //printf("releasing %p times now:%d\r\n", this, int(this->times_taken) );
 205     if( this->times_taken < 1 ){
 206         this->player->kernel->call_event(ON_BLOCK_END, this);
 207         this->pop_and_execute_gcode(this->player->kernel);
 208         Player* player = this->player;
 209
 210         if( player->queue.size() > 0 ){
 211             player->queue.delete_first();
 212         }
 213
 214         if( player->looking_for_new_block == false ){
 215             if( player->queue.size() > 0 ){
 216                 Block* candidate =  player->queue.get_ref(0);
 217                 if( candidate->is_ready ){
 218                     player->current_block = candidate;
 219                     player->kernel->call_event(ON_BLOCK_BEGIN, player->current_block);
 220                     if( player->current_block->times_taken < 1 ){
 221                         player->current_block->times_taken = 1;
 222                         player->current_block->release();
 223                     }
 224                 }else{
 225
 226                     player->current_block = NULL;
 227
 228                 }
 229             }else{
 230                 player->current_block = NULL;
 231             }
 232         }
 233     }
 234 }
 235
 236
 237