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 #include "libs/StreamOutputPool.h"
  18 #include "Stepper.h"
  19
  20 #include "mri.h"
  21
  22 using std::string;
  23 #include <vector>
  24
  25 // A block represents a movement, it's length for each stepper motor, and the corresponding acceleration curves.
  26 // It's stacked on a queue, and that queue is then executed in order, to move the motors.
  27 // Most of the accel math is also done in this class
  28 // And GCode objects for use in on_gcode_execute are also help in here
  29
  30 Block::Block()
  31 {
  32     clear();
  33 }
  34
  35 void Block::clear()
  36 {
  37     //commands.clear();
  38     //travel_distances.clear();
  39     gcodes.clear();
  40     clear_vector(this->steps);
  41
  42     steps_event_count   = 0;
  43     nominal_rate        = 0;
  44     nominal_speed       = 0.0F;
  45     millimeters         = 0.0F;
  46     entry_speed         = 0.0F;
  47     exit_speed          = 0.0F;
  48     rate_delta          = 0.0F;
  49     initial_rate        = -1;
  50     final_rate          = -1;
  51     accelerate_until    = 0;
  52     decelerate_after    = 0;
  53     direction_bits      = 0;
  54     recalculate_flag    = false;
  55     nominal_length_flag = false;
  56     max_entry_speed     = 0.0F;
  57     is_ready            = false;
  58     times_taken         = 0;
  59 }
  60
  61 void Block::debug()
  62 {
  63     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",
  64                                this,
  65                                          this->steps[0],
  66                                                this->steps[1],
  67                                                       this->steps[2],
  68                                                                this->steps_event_count,
  69                                                                              this->nominal_rate,
  70                                                                                    this->nominal_speed,
  71                                                                                             this->millimeters,
  72                                                                                                          this->rate_delta,
  73                                                                                                                  this->accelerate_until,
  74                                                                                                                          this->decelerate_after,
  75                                                                                                                                    this->initial_rate,
  76                                                                                                                                         this->final_rate,
  77                                                                                                                                                           this->entry_speed,
  78                                                                                                                                                                 this->max_entry_speed,
  79                                                                                                                                                                              this->times_taken,
  80                                                                                                                                                                                       this->is_ready,
  81                                                                                                                                                                                                 recalculate_flag?1:0,
  82                                                                                                                                                                                                           nominal_length_flag?1:0
  83                              );
  84 }
  85
  86
  87 /* Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
  88 // The factors represent a factor of braking and must be in the range 0.0-1.0.
  89 //                                +--------+ <- nominal_rate
  90 //                               /          \
  91 // nominal_rate*entry_factor -> +            \
  92 //                              |             + <- nominal_rate*exit_factor
  93 //                              +-------------+
  94 //                                  time -->
  95 */
  96 void Block::calculate_trapezoid( float entryspeed, float exitspeed )
  97 {
  98     // if block is currently executing, don't touch anything!
  99     if (times_taken)
 100         return;
 101
 102     // The planner passes us factors, we need to transform them in rates
 103     this->initial_rate = ceil(this->nominal_rate * entryspeed / this->nominal_speed);   // (step/s)
 104     this->final_rate   = ceil(this->nominal_rate * exitspeed  / this->nominal_speed);   // (step/s)
 105
 106     // How many steps to accelerate and decelerate
 107     float acceleration_per_second = this->rate_delta * THEKERNEL->stepper->get_acceleration_ticks_per_second(); // ( step/s^2)
 108     int accelerate_steps = ceil( this->estimate_acceleration_distance( this->initial_rate, this->nominal_rate, acceleration_per_second ) );
 109     int decelerate_steps = floor( this->estimate_acceleration_distance( this->nominal_rate, this->final_rate,  -acceleration_per_second ) );
 110
 111     // Calculate the size of Plateau of Nominal Rate ( during which we don't accelerate nor decelerate, but just cruise )
 112     int plateau_steps = this->steps_event_count - accelerate_steps - decelerate_steps;
 113
 114     // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will
 115     // have to use intersection_distance() to calculate when to abort acceleration and start braking
 116     // in order to reach the final_rate exactly at the end of this block.
 117     if (plateau_steps < 0) {
 118         accelerate_steps = ceil(this->intersection_distance(this->initial_rate, this->final_rate, acceleration_per_second, this->steps_event_count));
 119         accelerate_steps = max( accelerate_steps, 0 ); // Check limits due to numerical round-off
 120         accelerate_steps = min( accelerate_steps, int(this->steps_event_count) );
 121         plateau_steps = 0;
 122     }
 123     this->accelerate_until = accelerate_steps;
 124     this->decelerate_after = accelerate_steps + plateau_steps;
 125
 126     this->exit_speed = exitspeed;
 127 }
 128
 129 // Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
 130 // given acceleration:
 131 float Block::estimate_acceleration_distance(float initialrate, float targetrate, float acceleration)
 132 {
 133     return( ((targetrate * targetrate) - (initialrate * initialrate)) / (2.0F * acceleration));
 134 }
 135
 136 // This function gives you the point at which you must start braking (at the rate of -acceleration) if
 137 // you started at speed initial_rate and accelerated until this point and want to end at the final_rate after
 138 // a total travel of distance. This can be used to compute the intersection point between acceleration and
 139 // deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)
 140 //
 141 /*                          + <- some maximum rate we don't care about
 142                            /|\
 143                           / | \
 144                          /  |  + <- final_rate
 145                         /   |  |
 146        initial_rate -> +----+--+
 147                             ^ ^
 148                             | |
 149         intersection_distance distance */
 150 float Block::intersection_distance(float initialrate, float finalrate, float acceleration, float distance)
 151 {
 152     return((2 * acceleration * distance - initialrate * initialrate + finalrate * finalrate) / (4 * acceleration));
 153 }
 154
 155 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
 156 // acceleration within the allotted distance.
 157 inline float max_allowable_speed(float acceleration, float target_velocity, float distance)
 158 {
 159     return sqrtf(target_velocity * target_velocity - 2.0F * acceleration * distance);
 160 }
 161
 162
 163 // Called by Planner::recalculate() when scanning the plan from last to first entry.
 164 float Block::reverse_pass(float exit_speed)
 165 {
 166     // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
 167     // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
 168     // check for maximum allowable speed reductions to ensure maximum possible planned speed.
 169     if (this->entry_speed != this->max_entry_speed)
 170     {
 171         // If nominal length true, max junction speed is guaranteed to be reached. Only compute
 172         // for max allowable speed if block is decelerating and nominal length is false.
 173         if ((!this->nominal_length_flag) && (this->max_entry_speed > exit_speed))
 174         {
 175             float max_entry_speed = max_allowable_speed(-THEKERNEL->planner->get_acceleration(), exit_speed, this->millimeters);
 176
 177             this->entry_speed = min(max_entry_speed, this->max_entry_speed);
 178
 179             return this->entry_speed;
 180         }
 181         else
 182             this->entry_speed = this->max_entry_speed;
 183     }
 184
 185     return this->entry_speed;
 186 }
 187
 188
 189 // Called by Planner::recalculate() when scanning the plan from first to last entry.
 190 // returns maximum exit speed of this block
 191 float Block::forward_pass(float prev_max_exit_speed)
 192 {
 193     // If the previous block is an acceleration block, but it is not long enough to complete the
 194     // full speed change within the block, we need to adjust the entry speed accordingly. Entry
 195     // speeds have already been reset, maximized, and reverse planned by reverse planner.
 196     // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
 197
 198     // TODO: find out if both of these checks are necessary
 199     if (prev_max_exit_speed > nominal_speed)
 200         prev_max_exit_speed = nominal_speed;
 201     if (prev_max_exit_speed > max_entry_speed)
 202         prev_max_exit_speed = max_entry_speed;
 203
 204     if (prev_max_exit_speed <= entry_speed)
 205     {
 206         // accel limited
 207         entry_speed = prev_max_exit_speed;
 208         // since we're now acceleration or cruise limited
 209         // we don't need to recalculate our entry speed anymore
 210         recalculate_flag = false;
 211     }
 212     // else
 213     // // decel limited, do nothing
 214
 215     return max_exit_speed();
 216 }
 217
 218 float Block::max_exit_speed()
 219 {
 220     // if block is currently executing, return cached exit speed from calculate_trapezoid
 221     // this ensures that a block following a currently executing block will have correct entry speed
 222     if (times_taken)
 223         return exit_speed;
 224
 225     // if nominal_length_flag is asserted
 226     // we are guaranteed to reach nominal speed regardless of entry speed
 227     // thus, max exit will always be nominal
 228     if (nominal_length_flag)
 229         return nominal_speed;
 230
 231     // otherwise, we have to work out max exit speed based on entry and acceleration
 232     float max = max_allowable_speed(-THEKERNEL->planner->get_acceleration(), this->entry_speed, this->millimeters);
 233
 234     return min(max, nominal_speed);
 235 }
 236
 237 // Gcodes are attached to their respective blocks so that on_gcode_execute can be called with it
 238 void Block::append_gcode(Gcode* gcode)
 239 {
 240     Gcode new_gcode = *gcode;
 241     gcodes.push_back(new_gcode);
 242 }
 243
 244 void Block::begin()
 245 {
 246     recalculate_flag = false;
 247
 248     if (!is_ready)
 249         __debugbreak();
 250
 251     times_taken = -1;
 252
 253     // execute all the gcodes related to this block
 254     for(unsigned int index = 0; index < gcodes.size(); index++)
 255         THEKERNEL->call_event(ON_GCODE_EXECUTE, &(gcodes[index]));
 256
 257     THEKERNEL->call_event(ON_BLOCK_BEGIN, this);
 258
 259     if (times_taken < 0)
 260         release();
 261 }
 262
 263 // Signal the conveyor that this block is ready to be injected into the system
 264 void Block::ready()
 265 {
 266     this->is_ready = true;
 267 }
 268
 269 // Mark the block as taken by one more module
 270 void Block::take()
 271 {
 272     if (times_taken < 0)
 273         times_taken = 0;
 274     times_taken++;
 275 }
 276
 277 // Mark the block as no longer taken by one module, go to next block if this free's it
 278 void Block::release()
 279 {
 280     if (--this->times_taken <= 0)
 281     {
 282         times_taken = 0;
 283         if (is_ready)
 284         {
 285             is_ready = false;
 286             THEKERNEL->call_event(ON_BLOCK_END, this);
 287
 288             // ensure conveyor gets called last
 289             THEKERNEL->conveyor->on_block_end(this);
 290         }
 291     }
 292 }