70 lines
3.2 KiB
C
70 lines
3.2 KiB
C
/*
|
|
motion_plan.c - buffers movement commands and manages the acceleration profile plan
|
|
Part of Grbl
|
|
|
|
Copyright (c) 2009-2011 Simen Svale Skogsrud
|
|
|
|
Grbl 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.
|
|
|
|
Grbl 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 Grbl. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <inttypes.h>
|
|
#include <math.h>
|
|
|
|
#include "motion_plan.h"
|
|
#include "nuts_bolts.h"
|
|
#include "stepper.h"
|
|
|
|
struct Block block_buffer[BLOCK_BUFFER_SIZE]; // A ring buffer for motion instructions
|
|
volatile int block_buffer_head = 0; // Index of the next block to be pushed
|
|
volatile int block_buffer_tail = 0; // Index of the block to process now
|
|
|
|
inline uint32_t estimate_acceleration_distance(int32_t current_rate, int32_t target_rate, int32_t acceleration) {
|
|
return((target_rate*target_rate-current_rate*current_rate)/(2*acceleration));
|
|
}
|
|
|
|
inline uint32_t estimate_acceleration_ticks(int32_t start_rate, int32_t acceleration_per_tick, int32_t step_events) {
|
|
return(
|
|
round(
|
|
(sqrt(2*acceleration_per_tick*step_events+(start_rate*start_rate))-start_rate)/
|
|
acceleration_per_tick));
|
|
}
|
|
|
|
// Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
|
|
// In practice both factors must be in the range 0 ... 1.0
|
|
void calculate_trapezoid_for_block(struct Block *block, double entry_factor, double exit_factor) {
|
|
block->initial_rate = max(round(block->nominal_rate*entry_factor),MINIMAL_STEP_RATE);
|
|
int32_t final_rate = max(round(block->nominal_rate*entry_factor),MINIMAL_STEP_RATE);
|
|
int32_t acceleration_per_second = block->rate_delta*ACCELERATION_TICKS_PER_SECOND;
|
|
int32_t acceleration_steps =
|
|
estimate_acceleration_distance(block->initial_rate, block->nominal_rate, acceleration_per_second);
|
|
int32_t decelleration_steps =
|
|
estimate_acceleration_distance(block->nominal_rate, final_rate, -acceleration_per_second);
|
|
// Check if the acceleration and decelleration periods overlap. In that case nominal_speed will
|
|
// never be reached but that's okay. Just truncate both periods proportionally so that they
|
|
// fit within the allotted step events.
|
|
int32_t plateau_steps = block->step_event_count-acceleration_steps-decelleration_steps;
|
|
if (plateau_steps < 0) {
|
|
int32_t half_overlap_region = fabs(plateau_steps)/2;
|
|
plateau_steps = 0;
|
|
acceleration_steps = max(acceleration_steps-half_overlap_region,0);
|
|
decelleration_steps = max(decelleration_steps-half_overlap_region,0);
|
|
}
|
|
block->accelerate_ticks = estimate_acceleration_ticks(block->initial_rate, block->rate_delta, acceleration_steps);
|
|
if (plateau_steps) {
|
|
block->plateau_ticks = round(1.0*plateau_steps/(block->nominal_rate*ACCELERATION_TICKS_PER_SECOND));
|
|
} else {
|
|
block->plateau_ticks = 0;
|
|
}
|
|
}
|