Diff: modules/robot/Block.cpp

Revision:

0:31e91bb0ef3c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/robot/Block.cpp	Tue Jul 31 21:11:18 2012 +0000
@@ -0,0 +1,221 @@
+/*  
+      This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/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/>. 
+*/
+
+#include "libs/Module.h"
+#include "libs/Kernel.h"
+#include "libs/nuts_bolts.h"
+#include <math.h>
+#include <string>
+#include "Block.h"
+#include "Planner.h"
+#include "Player.h"
+using std::string;
+#include <vector>
+#include "../communication/utils/Gcode.h"
+
+Block::Block(){
+    clear_vector(this->steps);
+    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.
+    this->is_ready = false;
+    this->initial_rate = -1;
+    this->final_rate = -1;
+}
+
+void Block::debug(Kernel* kernel){
+    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 );
+}
+
+
+// Calculate a braking factor to reach baseline speed which is max_jerk/2, e.g. the
+// speed under which you cannot exceed max_jerk no matter what you do.
+double Block::compute_factor_for_safe_speed(){
+    return( this->planner->max_jerk / this->nominal_speed ); 
+}
+
+
+// Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
+// The factors represent a factor of braking and must be in the range 0.0-1.0.
+//                                +--------+ <- nominal_rate
+//                               /          \
+// nominal_rate*entry_factor -> +            \
+//                              |             + <- nominal_rate*exit_factor
+//                              +-------------+
+//                                  time -->
+void Block::calculate_trapezoid( double entryfactor, double exitfactor ){
+
+    this->initial_rate = ceil(this->nominal_rate * entryfactor);   // (step/min) 
+    this->final_rate   = ceil(this->nominal_rate * exitfactor);    // (step/min)
+    double acceleration_per_minute = this->rate_delta * this->planner->kernel->stepper->acceleration_ticks_per_second * 60.0; 
+    int accelerate_steps = ceil( this->estimate_acceleration_distance( this->initial_rate, this->nominal_rate, acceleration_per_minute ) );
+    int decelerate_steps = ceil( this->estimate_acceleration_distance( this->nominal_rate, this->final_rate,  -acceleration_per_minute ) );
+
+    // Calculate the size of Plateau of Nominal Rate.
+    int plateau_steps = this->steps_event_count-accelerate_steps-decelerate_steps;
+
+   // Is the Plateau of Nominal Rate smaller than nothing? That means no cruising, and we will
+   // have to use intersection_distance() to calculate when to abort acceleration and start braking
+   // in order to reach the final_rate exactly at the end of this block.
+   if (plateau_steps < 0) {
+       accelerate_steps = ceil(this->intersection_distance(this->initial_rate, this->final_rate, acceleration_per_minute, this->steps_event_count));
+       accelerate_steps = max( accelerate_steps, 0 ); // Check limits due to numerical round-off
+       accelerate_steps = min( accelerate_steps, int(this->steps_event_count) );
+       plateau_steps = 0;
+   }
+   
+   this->accelerate_until = accelerate_steps;
+   this->decelerate_after = accelerate_steps+plateau_steps; 
+
+   // 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
+   if( this->final_rate < 0.01 ){
+        this->decelerate_after += ( this->nominal_rate / 60 / this->planner->kernel->stepper->acceleration_ticks_per_second ) * 3;
+    }
+
+}
+
+// Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
+// given acceleration:
+double Block::estimate_acceleration_distance(double initialrate, double targetrate, double acceleration) {
+      return( (targetrate*targetrate-initialrate*initialrate)/(2L*acceleration));
+}
+
+// This function gives you the point at which you must start braking (at the rate of -acceleration) if
+// you started at speed initial_rate and accelerated until this point and want to end at the final_rate after
+// a total travel of distance. This can be used to compute the intersection point between acceleration and
+// deceleration in the cases where the trapezoid has no plateau (i.e. never reaches maximum speed)
+//
+/*                          + <- some maximum rate we don't care about
+                           /|\
+                          / | \
+                         /  |  + <- final_rate
+                        /   |  |
+       initial_rate -> +----+--+
+                            ^ ^
+                            | |
+        intersection_distance distance */
+double Block::intersection_distance(double initialrate, double finalrate, double acceleration, double distance) {
+   return((2*acceleration*distance-initialrate*initialrate+finalrate*finalrate)/(4*acceleration));
+}
+
+// Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
+// acceleration within the allotted distance.
+inline double 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
+  );
+}
+
+
+// Called by Planner::recalculate() when scanning the plan from last to first entry.
+void Block::reverse_pass(Block* next, Block* previous){
+
+    if (next) {
+        // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
+        // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
+        // check for maximum allowable speed reductions to ensure maximum possible planned speed.
+        if (this->entry_speed != this->max_entry_speed) {
+
+            // If nominal length true, max junction speed is guaranteed to be reached. Only compute
+            // for max allowable speed if block is decelerating and nominal length is false.
+            if ((!this->nominal_length_flag) && (this->max_entry_speed > next->entry_speed)) {
+                this->entry_speed = min( this->max_entry_speed, max_allowable_speed(-this->planner->acceleration,next->entry_speed,this->millimeters));
+            } else {
+                this->entry_speed = this->max_entry_speed;
+            }
+            this->recalculate_flag = true;
+
+        }
+    } // Skip last block. Already initialized and set for recalculation.
+
+}
+
+
+// Called by Planner::recalculate() when scanning the plan from first to last entry.
+void Block::forward_pass(Block* previous, Block* next){
+
+    if(!previous) { return; } // Begin planning after buffer_tail
+
+    // If the previous block is an acceleration block, but it is not long enough to complete the
+    // full speed change within the block, we need to adjust the entry speed accordingly. Entry
+    // speeds have already been reset, maximized, and reverse planned by reverse planner.
+    // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
+    if (!previous->nominal_length_flag) {
+        if (previous->entry_speed < this->entry_speed) {
+          double entry_speed = min( this->entry_speed,
+            max_allowable_speed(-this->planner->acceleration,previous->entry_speed,previous->millimeters) );
+
+          // Check for junction speed change
+          if (this->entry_speed != entry_speed) {
+            this->entry_speed = entry_speed;
+            this->recalculate_flag = true;
+          }
+        }
+    }
+      
+}
+
+
+// Gcodes are attached to their respective blocks so that on_gcode_execute can be called with it
+void Block::append_gcode(Gcode* gcode){
+   __disable_irq();
+   this->gcodes.push_back(*gcode);
+   __enable_irq();
+}
+
+// The attached gcodes are then poped and the on_gcode_execute event is called with them as a parameter
+void Block::pop_and_execute_gcode(Kernel* &kernel){
+    Block* block = const_cast<Block*>(this);
+    for(unsigned short index=0; index<block->gcodes.size(); index++){
+        kernel->call_event(ON_GCODE_EXECUTE, &(block->gcodes[index]));
+    }
+}
+
+// Signal the player that this block is ready to be injected into the system
+void Block::ready(){
+    this->is_ready = true;
+    this->player->new_block_added();
+}
+
+// Mark the block as taken by one more module
+void Block::take(){
+    this->times_taken++;
+}
+
+// Mark the block as no longer taken by one module, go to next block if this free's it
+void Block::release(){
+    this->times_taken--;
+    if( this->times_taken < 1 ){
+        this->player->kernel->call_event(ON_BLOCK_END, this);
+        this->pop_and_execute_gcode(this->player->kernel);
+        Player* player = this->player;
+
+        if( player->queue.size() > 0 ){ 
+            player->queue.delete_first();
+        } 
+
+        if( player->looking_for_new_block == false ){
+            if( player->queue.size() > 0 ){
+                Block* candidate =  player->queue.get_ref(0);
+                if( candidate->is_ready ){
+                    player->current_block = candidate;
+                    player->kernel->call_event(ON_BLOCK_BEGIN, player->current_block);
+                    if( player->current_block->times_taken < 1 ){
+                        player->current_block->release();
+                    }
+                }else{
+
+                    player->current_block = NULL;
+
+                } 
+            }else{
+                player->current_block = NULL;
+            }
+        }
+    }
+}
+
+
+