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 "Conveyor.h"
  16 #include "Gcode.h"
  17
  18 #include "mri.h"
  19
  20 using std::string;
  21 #include <vector>
  22
  23 // A block represents a movement, it's length for each stepper motor, and the corresponding acceleration curves.
  24 // It's stacked on a queue, and that queue is then executed in order, to move the motors.
  25 // Most of the accel math is also done in this class
  26 // And GCode objects for use in on_gcode_execute are also help in here
  27
  28 Block::Block()
  29 {
  30     clear();
  31 }
  32
  33 void Block::clear()
  34 {
  35     //commands.clear();
  36     //travel_distances.clear();
  37     gcodes.clear();
  38     clear_vector(this->steps);
  39
  40     steps_event_count   = 0;
  41     nominal_rate        = 0;
  42     nominal_speed       = 0.0F;
  43     millimeters         = 0.0F;
  44     entry_speed         = 0.0F;
  45     exit_speed          = 0.0F;
  46     rate_delta          = 0.0F;
  47     initial_rate        = -1;
  48     final_rate          = -1;
  49     accelerate_until    = 0;
  50     decelerate_after    = 0;
  51     direction_bits      = 0;
  52     recalculate_flag    = false;
  53     nominal_length_flag = false;
  54     max_entry_speed     = 0.0F;
  55     is_ready            = false;
  56     times_taken         = 0;
  57 }
  58
  59 void Block::debug()
  60 {
  61     THEKERNEL->streams->printf("%p: steps:X%04d Y%04d Z%04d(max:%4d) nominal:r%10d/s%6.1f mm:%9.6f rdelta:%8f acc:%5d dec:%5d rates:%10d>%10d  entry/max: %10.4f/%10.4f taken:%d ready:%d recalc:%d nomlen:%d\r\n",
  62                                this,
  63                                          this->steps[0],
  64                                                this->steps[1],
  65                                                       this->steps[2],
  66                                                                this->steps_event_count,
  67                                                                              this->nominal_rate,
  68                                                                                    this->nominal_speed,
  69                                                                                             this->millimeters,
  70                                                                                                          this->rate_delta,
  71                                                                                                                  this->accelerate_until,
  72                                                                                                                          this->decelerate_after,
  73                                                                                                                                    this->initial_rate,
  74                                                                                                                                         this->final_rate,
  75                                                                                                                                                           this->entry_speed,
  76                                                                                                                                                                 this->max_entry_speed,
  77                                                                                                                                                                              this->times_taken,
  78                                                                                                                                                                                       this->is_ready,
  79                                                                                                                                                                                                 recalculate_flag?1:0,
  80                                                                                                                                                                                                           nominal_length_flag?1:0
  81                              );
  82 }
  83
  84
  85 /* Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
  86 // The factors represent a factor of braking and must be in the range 0.0-1.0.
  87 //                                +--------+ <- nominal_rate
  88 //                               /          \
  89 // nominal_rate*entry_factor -> +            \
  90 //                              |             + <- nominal_rate*exit_factor
  91 //                              +-------------+
  92 //                                  time -->
  93 */
  94 void Block::calculate_trapezoid( float entryspeed, float exitspeed )
  95 {
  96     // if block is currently executing, don't touch anything!
  97     if (times_taken)
  98         return;
  99
 100     // The planner passes us factors, we need to transform them in rates
 101     this->initial_rate = ceil(this->nominal_rate * entryspeed / this->nominal_speed);   // (step/min)
 102     this->final_rate   = ceil(this->nominal_rate * exitspeed  / this->nominal_speed);   // (step/min)
 103
 104     // How many steps to accelerate and decelerate
 105     float acceleration_per_minute = this->rate_delta * THEKERNEL->stepper->acceleration_ticks_per_second * 60.0; // ( step/min^2)
 106     int accelerate_steps = ceil( this->estimate_acceleration_distance( this->initial_rate, this->nominal_rate, acceleration_per_minute ) );
 107     int decelerate_steps = floor( this->estimate_acceleration_distance( this->nominal_rate, this->final_rate,  -acceleration_per_minute ) );
 108
 109     // Calculate the size of Plateau of Nominal Rate ( during which we don't accelerate nor decelerate, but just cruise )
 110     int plateau_steps = this->steps_event_count - accelerate_steps - decelerate_steps;
 111
 112     // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will
 113     // have to use intersection_distance() to calculate when to abort acceleration and start braking
 114     // in order to reach the final_rate exactly at the end of this block.
 115     if (plateau_steps < 0) {
 116         accelerate_steps = ceil(this->intersection_distance(this->initial_rate, this->final_rate, acceleration_per_minute, this->steps_event_count));
 117         accelerate_steps = max( accelerate_steps, 0 ); // Check limits due to numerical round-off
 118         accelerate_steps = min( accelerate_steps, int(this->steps_event_count) );
 119         plateau_steps = 0;
 120     }
 121     this->accelerate_until = accelerate_steps;
 122     this->decelerate_after = accelerate_steps + plateau_steps;
 123
 124     this->exit_speed = exitspeed;
 125 }
 126
 127 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
 128 // given acceleration:
 129 float Block::estimate_acceleration_distance(float initialrate, float targetrate, float acceleration)
 130 {
 131     return( ((targetrate * targetrate) - (initialrate * initialrate)) / (2.0F * acceleration));
 132 }
 133
 134 // This function gives you the point at which you must start braking (at the rate of -acceleration) if
 135 // you started at speed initial_rate and accelerated until this point and want to end at the final_rate after
 136 // a total travel of distance. This can be used to compute the intersection point between acceleration and
 137 // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)
 138 //
 139 /*                          + <- some maximum rate we don't care about
 140                            /|\
 141                           / | \
 142                          /  |  + <- final_rate
 143                         /   |  |
 144        initial_rate -> +----+--+
 145                             ^ ^
 146                             | |
 147         intersection_distance distance */
 148 float Block::intersection_distance(float initialrate, float finalrate, float acceleration, float distance)
 149 {
 150     return((2 * acceleration * distance - initialrate * initialrate + finalrate * finalrate) / (4 * acceleration));
 151 }
 152
 153 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
 154 // acceleration within the allotted distance.
 155 inline float max_allowable_speed(float acceleration, float target_velocity, float distance)
 156 {
 157     return sqrtf(target_velocity * target_velocity - 2.0F * acceleration * distance);
 158 }
 159
 160
 161 // Called by Planner::recalculate() when scanning the plan from last to first entry.
 162 float Block::reverse_pass(float exit_speed)
 163 {
 164     // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
 165     // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
 166     // check for maximum allowable speed reductions to ensure maximum possible planned speed.
 167     if (this->entry_speed != this->max_entry_speed)
 168     {
 169         // If nominal length true, max junction speed is guaranteed to be reached. Only compute
 170         // for max allowable speed if block is decelerating and nominal length is false.
 171         if ((!this->nominal_length_flag) && (this->max_entry_speed > exit_speed))
 172         {
 173             float max_entry_speed = max_allowable_speed(-THEKERNEL->planner->acceleration, exit_speed, this->millimeters);
 174
 175             this->entry_speed = min(max_entry_speed, this->max_entry_speed);
 176
 177             return this->entry_speed;
 178         }
 179         else
 180             this->entry_speed = this->max_entry_speed;
 181     }
 182
 183     return this->entry_speed;
 184 }
 185
 186
 187 // Called by Planner::recalculate() when scanning the plan from first to last entry.
 188 // returns maximum exit speed of this block
 189 float Block::forward_pass(float prev_max_exit_speed)
 190 {
 191     // If the previous block is an acceleration block, but it is not long enough to complete the
 192     // full speed change within the block, we need to adjust the entry speed accordingly. Entry
 193     // speeds have already been reset, maximized, and reverse planned by reverse planner.
 194     // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
 195
 196     // TODO: find out if both of these checks are necessary
 197     if (prev_max_exit_speed > nominal_speed)
 198         prev_max_exit_speed = nominal_speed;
 199     if (prev_max_exit_speed > max_entry_speed)
 200         prev_max_exit_speed = max_entry_speed;
 201
 202     if (prev_max_exit_speed <= entry_speed)
 203     {
 204         // accel limited
 205         entry_speed = prev_max_exit_speed;
 206         // since we're now acceleration or cruise limited
 207         // we don't need to recalculate our entry speed anymore
 208         recalculate_flag = false;
 209     }
 210     // else
 211     // // decel limited, do nothing
 212
 213     return max_exit_speed();
 214 }
 215
 216 float Block::max_exit_speed()
 217 {
 218     // if block is currently executing, return cached exit speed from calculate_trapezoid
 219     // this ensures that a block following a currently executing block will have correct entry speed
 220     if (times_taken)
 221         return exit_speed;
 222
 223     // if nominal_length_flag is asserted
 224     // we are guaranteed to reach nominal speed regardless of entry speed
 225     // thus, max exit will always be nominal
 226     if (nominal_length_flag)
 227         return nominal_speed;
 228
 229     // otherwise, we have to work out max exit speed based on entry and acceleration
 230     float max = max_allowable_speed(-THEKERNEL->planner->acceleration, this->entry_speed, this->millimeters);
 231
 232     return min(max, nominal_speed);
 233 }
 234
 235 // Gcodes are attached to their respective blocks so that on_gcode_execute can be called with it
 236 void Block::append_gcode(Gcode* gcode)
 237 {
 238     Gcode new_gcode = *gcode;
 239     gcodes.push_back(new_gcode);
 240 }
 241
 242 void Block::begin()
 243 {
 244     recalculate_flag = false;
 245
 246     if (!is_ready)
 247         __debugbreak();
 248
 249     times_taken = -1;
 250
 251     // execute all the gcodes related to this block
 252     for(unsigned int index = 0; index < gcodes.size(); index++)
 253         THEKERNEL->call_event(ON_GCODE_EXECUTE, &(gcodes[index]));
 254
 255     THEKERNEL->call_event(ON_BLOCK_BEGIN, this);
 256
 257     if (times_taken < 0)
 258         release();
 259 }
 260
 261 // Signal the conveyor that this block is ready to be injected into the system
 262 void Block::ready()
 263 {
 264     this->is_ready = true;
 265 }
 266
 267 // Mark the block as taken by one more module
 268 void Block::take()
 269 {
 270     if (times_taken < 0)
 271         times_taken = 0;
 272     times_taken++;
 273 }
 274
 275 // Mark the block as no longer taken by one module, go to next block if this free's it
 276 void Block::release()
 277 {
 278     if (--this->times_taken <= 0)
 279     {
 280         times_taken = 0;
 281         if (is_ready)
 282         {
 283             is_ready = false;
 284             THEKERNEL->call_event(ON_BLOCK_END, this);
 285
 286             // ensure conveyor gets called last
 287             THEKERNEL->conveyor->on_block_end(this);
 288         }
 289     }
 290 }