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refactored block buffer into separate module motion_plan pending the addition of the actual look ahead planner

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Simen Svale Skogsrud
2011-01-14 16:45:18 +01:00
parent b628a4aabf
commit 49a16cb777
21 changed files with 163 additions and 146 deletions
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motion_plan.c Normal file
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/*
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;
}
}