ManuelW/grbl-LPC-CoreXY
1
0
Fork 0
Code Issues Pull Requests Releases 1 Wiki Activity

Initial v0.8 ALPHA commit. Features multi-tasking run-time command execution (feed hold, cycle start, reset, status query). Extensive re-structuring of code for future features.

Browse Source 
- ALPHA status. - Multitasking ability with run-time command executions
for real-time control and feedback. - Decelerating feed hold and resume
during operation. - System abort/reset, which immediately kills all
movement and re-initializes grbl. - Re-structured grbl to easily allow
for new features: Status reporting, jogging, backlash compensation. (To
be completed in the following releases.) - Resized TX/RX serial buffers
(32/128 bytes) - Increased planner buffer size to 20 blocks. - Updated
documentation.
This commit is contained in:
Sonny Jeon
2011-12-08 18:47:48 -07:00
parent 292fcca67f
commit 03e2ca7cd5
23 changed files with 841 additions and 477 deletions
Download Patch File Download Diff File Expand all files Collapse all files

287
planner.c
View File

@ -4,6 +4,7 @@
Copyright (c) 2009-2011 Simen Svale Skogsrud
Copyright (c) 2011 Sungeun K. Jeon
Copyright (c) 2011 Jens Geisler
Grbl is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -30,28 +31,26 @@
#include "stepper.h"
#include "settings.h"
#include "config.h"
#include "protocol.h"
// The number of linear motions that can be in the plan at any give time
#ifdef __AVR_ATmega328P__
#define BLOCK_BUFFER_SIZE 18
#else
#define BLOCK_BUFFER_SIZE 5
#endif
#define BLOCK_BUFFER_SIZE 20
static block_t block_buffer[BLOCK_BUFFER_SIZE]; // A ring buffer for motion instructions
static volatile uint8_t block_buffer_head; // Index of the next block to be pushed
static volatile uint8_t block_buffer_tail; // Index of the block to process now
static uint8_t next_buffer_head; // Index of the next buffer head
static int32_t position[3]; // The current position of the tool in absolute steps
static int32_t position[3]; // The planner position of the tool in absolute steps
// static int32_t coord_offset[3]; // Current coordinate offset from machine zero in absolute steps
static double previous_unit_vec[3]; // Unit vector of previous path line segment
static double previous_nominal_speed; // Nominal speed of previous path line segment
static uint8_t acceleration_manager_enabled; // Acceleration management active?
// Returns the index of the next block in the ring buffer
// NOTE: Removed modulo (%) operator, which uses an expensive divide and multiplication.
static int8_t next_block_index(int8_t block_index) {
static uint8_t next_block_index(uint8_t block_index)
{
block_index++;
if (block_index == BLOCK_BUFFER_SIZE) { block_index = 0; }
return(block_index);
@ -59,7 +58,8 @@ static int8_t next_block_index(int8_t block_index) {
// Returns the index of the previous block in the ring buffer
static int8_t prev_block_index(int8_t block_index) {
static uint8_t prev_block_index(uint8_t block_index)
{
if (block_index == 0) { block_index = BLOCK_BUFFER_SIZE; }
block_index--;
return(block_index);
@ -68,7 +68,8 @@ static int8_t prev_block_index(int8_t block_index) {
// Calculates the distance (not time) it takes to accelerate from initial_rate to target_rate using the
// given acceleration:
static double estimate_acceleration_distance(double initial_rate, double target_rate, double acceleration) {
static double estimate_acceleration_distance(double initial_rate, double target_rate, double acceleration)
{
return( (target_rate*target_rate-initial_rate*initial_rate)/(2*acceleration) );
}
@ -86,7 +87,8 @@ static double estimate_acceleration_distance(double initial_rate, double target_
// 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)
static double intersection_distance(double initial_rate, double final_rate, double acceleration, double distance) {
static double intersection_distance(double initial_rate, double final_rate, double acceleration, double distance)
{
return( (2*acceleration*distance-initial_rate*initial_rate+final_rate*final_rate)/(4*acceleration) );
}
@ -96,13 +98,15 @@ static double intersection_distance(double initial_rate, double final_rate, doub
// NOTE: sqrt() reimplimented here from prior version due to improved planner logic. Increases speed
// in time critical computations, i.e. arcs or rapid short lines from curves. Guaranteed to not exceed
// BLOCK_BUFFER_SIZE calls per planner cycle.
static double max_allowable_speed(double acceleration, double target_velocity, double distance) {
static double max_allowable_speed(double acceleration, double target_velocity, double distance)
{
return( sqrt(target_velocity*target_velocity-2*acceleration*distance) );
}
// The kernel called by planner_recalculate() when scanning the plan from last to first entry.
static void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *next) {
static void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *next)
{
if (!current) { return; } // Cannot operate on nothing.
if (next) {
@ -128,8 +132,9 @@ static void planner_reverse_pass_kernel(block_t *previous, block_t *current, blo
// planner_recalculate() needs to go over the current plan twice. Once in reverse and once forward. This
// implements the reverse pass.
static void planner_reverse_pass() {
auto int8_t block_index = block_buffer_head;
static void planner_reverse_pass()
{
uint8_t block_index = block_buffer_head;
block_t *block[3] = {NULL, NULL, NULL};
while(block_index != block_buffer_tail) {
block_index = prev_block_index( block_index );
@ -143,7 +148,8 @@ static void planner_reverse_pass() {
// The kernel called by planner_recalculate() when scanning the plan from first to last entry.
static void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *next) {
static void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *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
@ -167,8 +173,9 @@ static void planner_forward_pass_kernel(block_t *previous, block_t *current, blo
// planner_recalculate() needs to go over the current plan twice. Once in reverse and once forward. This
// implements the forward pass.
static void planner_forward_pass() {
int8_t block_index = block_buffer_tail;
static void planner_forward_pass()
{
uint8_t block_index = block_buffer_tail;
block_t *block[3] = {NULL, NULL, NULL};
while(block_index != block_buffer_head) {
@ -194,8 +201,8 @@ static void planner_forward_pass() {
// The factors represent a factor of braking and must be in the range 0.0-1.0.
// This converts the planner parameters to the data required by the stepper controller.
// NOTE: Final rates must be computed in terms of their respective blocks.
static void calculate_trapezoid_for_block(block_t *block, double entry_factor, double exit_factor) {
static void calculate_trapezoid_for_block(block_t *block, double entry_factor, double exit_factor)
{
block->initial_rate = ceil(block->nominal_rate*entry_factor); // (step/min)
block->final_rate = ceil(block->nominal_rate*exit_factor); // (step/min)
int32_t acceleration_per_minute = block->rate_delta*ACCELERATION_TICKS_PER_SECOND*60.0; // (step/min^2)
@ -235,8 +242,9 @@ static void calculate_trapezoid_for_block(block_t *block, double entry_factor, d
// planner_recalculate() after updating the blocks. Any recalulate flagged junction will
// compute the two adjacent trapezoids to the junction, since the junction speed corresponds
// to exit speed and entry speed of one another.
static void planner_recalculate_trapezoids() {
int8_t block_index = block_buffer_tail;
static void planner_recalculate_trapezoids()
{
uint8_t block_index = block_buffer_tail;
block_t *current;
block_t *next = NULL;
@ -281,63 +289,71 @@ static void planner_recalculate_trapezoids() {
// All planner computations are performed with doubles (float on Arduinos) to minimize numerical round-
// off errors. Only when planned values are converted to stepper rate parameters, these are integers.
static void planner_recalculate() {
static void planner_recalculate()
{
planner_reverse_pass();
planner_forward_pass();
planner_recalculate_trapezoids();
}
void plan_init() {
block_buffer_head = 0;
block_buffer_tail = 0;
plan_set_acceleration_manager_enabled(true);
void plan_reset_buffer()
{
block_buffer_tail = block_buffer_head;
next_buffer_head = next_block_index(block_buffer_head);
}
void plan_init()
{
plan_reset_buffer();
clear_vector(position);
// clear_vector(coord_offset);
clear_vector_double(previous_unit_vec);
previous_nominal_speed = 0.0;
}
void plan_set_acceleration_manager_enabled(uint8_t enabled) {
if ((!!acceleration_manager_enabled) != (!!enabled)) {
st_synchronize();
acceleration_manager_enabled = !!enabled;
}
}
int plan_is_acceleration_manager_enabled() {
return(acceleration_manager_enabled);
}
void plan_discard_current_block() {
void plan_discard_current_block()
{
if (block_buffer_head != block_buffer_tail) {
block_buffer_tail = next_block_index( block_buffer_tail );
}
}
block_t *plan_get_current_block() {
block_t *plan_get_current_block()
{
if (block_buffer_head == block_buffer_tail) { return(NULL); }
return(&block_buffer[block_buffer_tail]);
}
// Returns the availability status of the block ring buffer. True, if full.
uint8_t plan_check_full_buffer()
{
if (block_buffer_tail == next_buffer_head) { return(true); }
return(false);
}
// Block until all buffered steps are executed.
void plan_synchronize()
{
while(plan_get_current_block()) {
protocol_execute_runtime(); // Check and execute run-time commands
if (sys_abort) { return; } // Check for system abort
}
}
// Add a new linear movement to the buffer. x, y and z is the signed, absolute target position in
// millimaters. Feed rate specifies the speed of the motion. If feed rate is inverted, the feed
// millimeters. Feed rate specifies the speed of the motion. If feed rate is inverted, the feed
// rate is taken to mean "frequency" and would complete the operation in 1/feed_rate minutes.
void plan_buffer_line(double x, double y, double z, double feed_rate, uint8_t invert_feed_rate) {
// NOTE: Assumes buffer is available. Buffer checks are handled at a higher level by motion_control.
void plan_buffer_line(double x, double y, double z, double feed_rate, uint8_t invert_feed_rate)
{
// Prepare to set up new block
block_t *block = &block_buffer[block_buffer_head];
// Calculate target position in absolute steps
int32_t target[3];
target[X_AXIS] = lround(x*settings.steps_per_mm[X_AXIS]);
target[Y_AXIS] = lround(y*settings.steps_per_mm[Y_AXIS]);
target[Z_AXIS] = lround(z*settings.steps_per_mm[Z_AXIS]);
// Calculate the buffer head after we push this byte
int next_buffer_head = next_block_index( block_buffer_head );
// If the buffer is full: good! That means we are well ahead of the robot.
// Rest here until there is room in the buffer.
while(block_buffer_tail == next_buffer_head) { sleep_mode(); }
// Prepare to set up new block
block_t *block = &block_buffer[block_buffer_head];
// Compute direction bits for this block
block->direction_bits = 0;
@ -384,92 +400,113 @@ void plan_buffer_line(double x, double y, double z, double feed_rate, uint8_t in
block->rate_delta = ceil( block->step_event_count*inverse_millimeters *
settings.acceleration / (60 * ACCELERATION_TICKS_PER_SECOND )); // (step/min/acceleration_tick)
// Perform planner-enabled calculations
if (acceleration_manager_enabled) {
// Compute path unit vector
double unit_vec[3];
// Compute path unit vector
double unit_vec[3];
unit_vec[X_AXIS] = delta_mm[X_AXIS]*inverse_millimeters;
unit_vec[Y_AXIS] = delta_mm[Y_AXIS]*inverse_millimeters;
unit_vec[Z_AXIS] = delta_mm[Z_AXIS]*inverse_millimeters;
// Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
// Let a circle be tangent to both previous and current path line segments, where the junction
// deviation is defined as the distance from the junction to the closest edge of the circle,
// colinear with the circle center. The circular segment joining the two paths represents the
// path of centripetal acceleration. Solve for max velocity based on max acceleration about the
// radius of the circle, defined indirectly by junction deviation. This may be also viewed as
// path width or max_jerk in the previous grbl version. This approach does not actually deviate
// from path, but used as a robust way to compute cornering speeds, as it takes into account the
// nonlinearities of both the junction angle and junction velocity.
double vmax_junction = MINIMUM_PLANNER_SPEED; // Set default max junction speed
unit_vec[X_AXIS] = delta_mm[X_AXIS]*inverse_millimeters;
unit_vec[Y_AXIS] = delta_mm[Y_AXIS]*inverse_millimeters;
unit_vec[Z_AXIS] = delta_mm[Z_AXIS]*inverse_millimeters;
// Skip first block or when previous_nominal_speed is used as a flag for homing and offset cycles.
if ((block_buffer_head != block_buffer_tail) && (previous_nominal_speed > 0.0)) {
// Compute cosine of angle between previous and current path. (prev_unit_vec is negative)
// NOTE: Max junction velocity is computed without sin() or acos() by trig half angle identity.
double cos_theta = - previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
- previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
- previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ;
// Skip and use default max junction speed for 0 degree acute junction.
if (cos_theta < 0.95) {
vmax_junction = min(previous_nominal_speed,block->nominal_speed);
// Skip and avoid divide by zero for straight junctions at 180 degrees. Limit to min() of nominal speeds.
if (cos_theta > -0.95) {
// Compute maximum junction velocity based on maximum acceleration and junction deviation
double sin_theta_d2 = sqrt(0.5*(1.0-cos_theta)); // Trig half angle identity. Always positive.
vmax_junction = min(vmax_junction,
sqrt(settings.acceleration * settings.junction_deviation * sin_theta_d2/(1.0-sin_theta_d2)) );
}
// Compute maximum allowable entry speed at junction by centripetal acceleration approximation.
// Let a circle be tangent to both previous and current path line segments, where the junction
// deviation is defined as the distance from the junction to the closest edge of the circle,
// colinear with the circle center. The circular segment joining the two paths represents the
// path of centripetal acceleration. Solve for max velocity based on max acceleration about the
// radius of the circle, defined indirectly by junction deviation. This may be also viewed as
// path width or max_jerk in the previous grbl version. This approach does not actually deviate
// from path, but used as a robust way to compute cornering speeds, as it takes into account the
// nonlinearities of both the junction angle and junction velocity.
double vmax_junction = MINIMUM_PLANNER_SPEED; // Set default max junction speed
// Skip first block or when previous_nominal_speed is used as a flag for homing and offset cycles.
if ((block_buffer_head != block_buffer_tail) && (previous_nominal_speed > 0.0)) {
// Compute cosine of angle between previous and current path. (prev_unit_vec is negative)
// NOTE: Max junction velocity is computed without sin() or acos() by trig half angle identity.
double cos_theta = - previous_unit_vec[X_AXIS] * unit_vec[X_AXIS]
- previous_unit_vec[Y_AXIS] * unit_vec[Y_AXIS]
- previous_unit_vec[Z_AXIS] * unit_vec[Z_AXIS] ;
// Skip and use default max junction speed for 0 degree acute junction.
if (cos_theta < 0.95) {
vmax_junction = min(previous_nominal_speed,block->nominal_speed);
// Skip and avoid divide by zero for straight junctions at 180 degrees. Limit to min() of nominal speeds.
if (cos_theta > -0.95) {
// Compute maximum junction velocity based on maximum acceleration and junction deviation
double sin_theta_d2 = sqrt(0.5*(1.0-cos_theta)); // Trig half angle identity. Always positive.
vmax_junction = min(vmax_junction,
sqrt(settings.acceleration * settings.junction_deviation * sin_theta_d2/(1.0-sin_theta_d2)) );
}
}
block->max_entry_speed = vmax_junction;
// Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED.
double v_allowable = max_allowable_speed(-settings.acceleration,MINIMUM_PLANNER_SPEED,block->millimeters);
block->entry_speed = min(vmax_junction, v_allowable);
// Initialize planner efficiency flags
// Set flag if block will always reach maximum junction speed regardless of entry/exit speeds.
// If a block can de/ac-celerate from nominal speed to zero within the length of the block, then
// the current block and next block junction speeds are guaranteed to always be at their maximum
// junction speeds in deceleration and acceleration, respectively. This is due to how the current
// block nominal speed limits both the current and next maximum junction speeds. Hence, in both
// the reverse and forward planners, the corresponding block junction speed will always be at the
// the maximum junction speed and may always be ignored for any speed reduction checks.
if (block->nominal_speed <= v_allowable) { block->nominal_length_flag = true; }
else { block->nominal_length_flag = false; }
block->recalculate_flag = true; // Always calculate trapezoid for new block
// Update previous path unit_vector and nominal speed
memcpy(previous_unit_vec, unit_vec, sizeof(unit_vec)); // previous_unit_vec[] = unit_vec[]
previous_nominal_speed = block->nominal_speed;
} else {
// Acceleration planner disabled. Set minimum that is required.
block->initial_rate = block->nominal_rate;
block->final_rate = block->nominal_rate;
block->accelerate_until = 0;
block->decelerate_after = block->step_event_count;
block->rate_delta = 0;
}
block->max_entry_speed = vmax_junction;
// Initialize block entry speed. Compute based on deceleration to user-defined MINIMUM_PLANNER_SPEED.
double v_allowable = max_allowable_speed(-settings.acceleration,MINIMUM_PLANNER_SPEED,block->millimeters);
block->entry_speed = min(vmax_junction, v_allowable);
// Initialize planner efficiency flags
// Set flag if block will always reach maximum junction speed regardless of entry/exit speeds.
// If a block can de/ac-celerate from nominal speed to zero within the length of the block, then
// the current block and next block junction speeds are guaranteed to always be at their maximum
// junction speeds in deceleration and acceleration, respectively. This is due to how the current
// block nominal speed limits both the current and next maximum junction speeds. Hence, in both
// the reverse and forward planners, the corresponding block junction speed will always be at the
// the maximum junction speed and may always be ignored for any speed reduction checks.
if (block->nominal_speed <= v_allowable) { block->nominal_length_flag = true; }
else { block->nominal_length_flag = false; }
block->recalculate_flag = true; // Always calculate trapezoid for new block
// Update previous path unit_vector and nominal speed
memcpy(previous_unit_vec, unit_vec, sizeof(unit_vec)); // previous_unit_vec[] = unit_vec[]
previous_nominal_speed = block->nominal_speed;
// Update buffer head and next buffer head indices
block_buffer_head = next_buffer_head;
next_buffer_head = next_block_index(block_buffer_head);
// Move buffer head
block_buffer_head = next_buffer_head;
// Update position
memcpy(position, target, sizeof(target)); // position[] = target[]
if (acceleration_manager_enabled) { planner_recalculate(); }
st_cycle_start();
planner_recalculate();
}
// Reset the planner position vector and planner speed
void plan_set_current_position(double x, double y, double z) {
void plan_set_current_position(double x, double y, double z)
{
// Track the position offset from the initial position
// TODO: Need to make sure coord_offset is robust and/or needed. Can be used for a soft reset,
// where the machine position is retained after a system abort/reset. However, this is not
// correlated to the actual machine position after a soft reset and may not be needed. This could
// be left to a user interface to maintain.
// coord_offset[X_AXIS] += position[X_AXIS];
// coord_offset[Y_AXIS] += position[Y_AXIS];
// coord_offset[Z_AXIS] += position[Z_AXIS];
position[X_AXIS] = lround(x*settings.steps_per_mm[X_AXIS]);
position[Y_AXIS] = lround(y*settings.steps_per_mm[Y_AXIS]);
position[Z_AXIS] = lround(z*settings.steps_per_mm[Z_AXIS]);
position[Z_AXIS] = lround(z*settings.steps_per_mm[Z_AXIS]);
// coord_offset[X_AXIS] -= position[X_AXIS];
// coord_offset[Y_AXIS] -= position[Y_AXIS];
// coord_offset[Z_AXIS] -= position[Z_AXIS];
previous_nominal_speed = 0.0; // Resets planner junction speeds. Assumes start from rest.
clear_vector_double(previous_unit_vec);
}
// Re-initialize buffer plan with a partially completed block, assumed to exist at the buffer tail.
// Called after a steppers have come to a complete stop for a feed hold and the cycle is stopped.
void plan_cycle_reinitialize(int32_t step_events_remaining)
{
block_t *block = &block_buffer[block_buffer_tail]; // Point to partially completed block
// Only remaining millimeters and step_event_count need to be updated for planner recalculate.
// Other variables (step_x, step_y, step_z, rate_delta, etc.) all need to remain the same to
// ensure the original planned motion is resumed exactly.
block->millimeters = (block->millimeters*step_events_remaining)/block->step_event_count;
block->step_event_count = step_events_remaining;
// Re-plan from a complete stop. Reset planner entry speeds and flags.
block->entry_speed = 0.0;
block->max_entry_speed = 0.0;
block->nominal_length_flag = false;
block->recalculate_flag = true;
planner_recalculate();
}