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AP_SafeRTL: move simplify and prune state into structures

This commit is contained in:
Randy Mackay 2017-08-31 15:20:20 +09:00
parent e0da7ed09c
commit 811e115a21
2 changed files with 90 additions and 84 deletions
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134
libraries/AP_SafeRTL/AP_SafeRTL.cpp
View File

@ -65,8 +65,8 @@ const AP_Param::GroupInfo AP_SafeRTL::var_info[] = {
* before they complete which is helpful when memory is filling up and we just
* need to quickly identify a handful of points which can be deleted.
*
* Once the algorithms have completed the _simplify_complete and
* _prune_complete flags are set to true. The "thorough cleanup" procedure,
* Once the algorithms have completed the simplify.complete and
* prune.complete flags are set to true. The "thorough cleanup" procedure,
* which is run as the vehicle initiates the SafeRTL flight mode, waits for
* these flags to become true. This can force the vehicle to pause for a few
* seconds before initiating the return journey.
@ -77,7 +77,7 @@ AP_SafeRTL::AP_SafeRTL(const AP_AHRS& ahrs, bool example_mode) :
_example_mode(example_mode)
{
AP_Param::setup_object_defaults(this, var_info);
_simplify_bitmask.setall();
_simplify.bitmask.setall();
}
// initialise safe rtl including setting up background processes
@ -99,19 +99,19 @@ void AP_SafeRTL::init()
// allocate arrays
_path = (Vector3f*)calloc(_points_max, sizeof(Vector3f));
_prunable_loops_max = _points_max * SAFERTL_PRUNING_LOOP_BUFFER_LEN_MULT;
_prunable_loops = (prune_loop_t*)calloc(_prunable_loops_max, sizeof(prune_loop_t));
_prune.loops_max = _points_max * SAFERTL_PRUNING_LOOP_BUFFER_LEN_MULT;
_prune.loops = (prune_loop_t*)calloc(_prune.loops_max, sizeof(prune_loop_t));
_simplify_stack_max = _points_max * SAFERTL_SIMPLIFY_STACK_LEN_MULT;
_simplify_stack = (simplify_start_finish_t*)calloc(_simplify_stack_max, sizeof(simplify_start_finish_t));
_simplify.stack_max = _points_max * SAFERTL_SIMPLIFY_STACK_LEN_MULT;
_simplify.stack = (simplify_start_finish_t*)calloc(_simplify.stack_max, sizeof(simplify_start_finish_t));
// check if memory allocation failed
if (_path == nullptr || _prunable_loops == nullptr || _simplify_stack == nullptr) {
if (_path == nullptr || _prune.loops == nullptr || _simplify.stack == nullptr) {
log_action(SRTL_DEACTIVATED_INIT_FAILED);
gcs().send_text(MAV_SEVERITY_WARNING, "SafeRTL deactivated: init failed");
free(_path);
free(_prunable_loops);
free(_simplify_stack);
free(_prune.loops);
free(_simplify.stack);
return;
}
@ -348,13 +348,13 @@ void AP_SafeRTL::run_background_cleanup()
}
// detect simplifications
if (!_simplify_complete) {
if (!_simplify.complete) {
detect_simplifications();
return;
}
// detect prunable loops
if (!_prune_complete) {
if (!_prune.complete) {
detect_loops();
return;
}
@ -370,7 +370,7 @@ void AP_SafeRTL::run_background_cleanup()
// the calls to remove_empty_points causes the detect_ algorithms to begin their calculations from scratch
void AP_SafeRTL::routine_cleanup()
{
const uint16_t potential_amount_to_simplify = _simplify_bitmask.size() - _simplify_bitmask.count();
const uint16_t potential_amount_to_simplify = _simplify.bitmask.size() - _simplify.bitmask.count();
// if simplifying will remove more than 10 points, just do it
if (potential_amount_to_simplify >= SAFERTL_CLEANUP_POINT_MIN) {
@ -385,9 +385,9 @@ void AP_SafeRTL::routine_cleanup()
}
uint16_t potential_amount_to_prune = 0;
for (uint16_t i = 0; i < _prunable_loops_count; i++) {
for (uint16_t i = 0; i < _prune.loops_count; i++) {
// add 1 at the end, because a pruned loop is always replaced by one new point.
potential_amount_to_prune += _prunable_loops[i].end_index - _prunable_loops[i].start_index + 1;
potential_amount_to_prune += _prune.loops[i].end_index - _prune.loops[i].start_index + 1;
}
// if pruning could remove 10+ points, prune loops until 10 or more points have been removed (doesn't necessarily prune all loops)
@ -423,11 +423,11 @@ bool AP_SafeRTL::thorough_cleanup(uint16_t path_points_count, ThoroughCleanupTyp
reset_if_new_points(path_points_count);
// if simplification is not complete, run it
if (!_simplify_complete && (clean_type != THOROUGH_CLEAN_PRUNE_ONLY)) {
if (!_simplify.complete && (clean_type != THOROUGH_CLEAN_PRUNE_ONLY)) {
detect_simplifications();
return false;
}
if (!_prune_complete && (clean_type != THOROUGH_CLEAN_SIMPLIFY_ONLY)) {
if (!_prune.complete && (clean_type != THOROUGH_CLEAN_SIMPLIFY_ONLY)) {
detect_loops();
return false;
}
@ -456,25 +456,25 @@ bool AP_SafeRTL::thorough_cleanup(uint16_t path_points_count, ThoroughCleanupTyp
}
// Simplifies a 3D path, according to the Ramer-Douglas-Peucker algorithm.
// _simplify_complete is set to true when all simplifications on the path have been identified
// _simplify.complete is set to true when all simplifications on the path have been identified
void AP_SafeRTL::detect_simplifications()
{
// complete immediately if only one segment
if (_simplify_path_points_count < 3) {
_simplify_complete = true;
if (_simplify.path_points_count < 3) {
_simplify.complete = true;
return;
}
// if not complete but also nothing to do, we must be restarting
if (_simplify_stack_count == 0) {
if (_simplify.stack_count == 0) {
// reset to beginning state. a single element in the array with start = first path point, finish = final path point
_simplify_stack[0].start = 0;
_simplify_stack[0].finish = _simplify_path_points_count-1;
_simplify_stack_count++;
_simplify.stack[0].start = 0;
_simplify.stack[0].finish = _simplify.path_points_count-1;
_simplify.stack_count++;
}
const uint32_t start_time_us = AP_HAL::micros();
while (_simplify_stack_count > 0) { // while there is something to do
while (_simplify.stack_count > 0) { // while there is something to do
// if this method has run for long enough, exit
if (AP_HAL::micros() - start_time_us > SAFERTL_SIMPLIFY_TIME_US) {
@ -482,7 +482,7 @@ void AP_SafeRTL::detect_simplifications()
}
// pop last item off the simplify stack
const simplify_start_finish_t tmp = _simplify_stack[--_simplify_stack_count];
const simplify_start_finish_t tmp = _simplify.stack[--_simplify.stack_count];
const uint16_t start_index = tmp.start;
const uint16_t end_index = tmp.finish;
@ -491,7 +491,7 @@ void AP_SafeRTL::detect_simplifications()
uint16_t farthest_point_index = start_index;
for (uint16_t i = start_index + 1; i < end_index; i++) {
// only check points that have not already been flagged for simplification
if (_simplify_bitmask.get(i)) {
if (_simplify.bitmask.get(i)) {
const float dist = _path[i].distance_to_segment(_path[start_index], _path[end_index]);
if (dist > max_dist) {
farthest_point_index = i;
@ -504,34 +504,34 @@ void AP_SafeRTL::detect_simplifications()
// so that on the next iteration we will check between start-to-farthestpoint and farthestpoint-to-end
if (max_dist > SAFERTL_SIMPLIFY_EPSILON) {
// if the to-do list is full, give up on simplifying. This should never happen.
if (_simplify_stack_count >= _simplify_stack_max) {
_simplify_complete = true;
if (_simplify.stack_count >= _simplify.stack_max) {
_simplify.complete = true;
return;
}
_simplify_stack[_simplify_stack_count++] = simplify_start_finish_t {start_index, farthest_point_index};
_simplify_stack[_simplify_stack_count++] = simplify_start_finish_t {farthest_point_index, end_index};
_simplify.stack[_simplify.stack_count++] = simplify_start_finish_t {start_index, farthest_point_index};
_simplify.stack[_simplify.stack_count++] = simplify_start_finish_t {farthest_point_index, end_index};
} else {
// if the farthest point was closer than ACCURACY * 0.5 we can simplify all points between start and end
for (uint16_t i = start_index + 1; i < end_index; i++) {
_simplify_bitmask.clear(i);
_simplify.bitmask.clear(i);
}
}
}
_simplify_complete = true;
_simplify.complete = true;
}
/**
* This method runs for the allotted time, and detects loops in a path. Any detected loops are added to _prunable_loops,
* This method runs for the allotted time, and detects loops in a path. Any detected loops are added to _prune.loops,
* this function does not alter the path in memory. It works by comparing the line segment between any two sequential points
* to the line segment between any other two sequential points. If they get close enough, anything between them could be pruned.
*
* reset_pruning should have been called at least once before this function is called to setup the indexes (_prune_i, etc)
* reset_pruning should have been called at least once before this function is called to setup the indexes (_prune.i, etc)
*/
void AP_SafeRTL::detect_loops()
{
// if there are less than 4 points (3 segments), mark complete
if (_prune_path_points_count < 4) {
_prune_complete = true;
if (_prune.path_points_count < 4) {
_prune.complete = true;
return;
}
@ -542,33 +542,33 @@ void AP_SafeRTL::detect_loops()
while (AP_HAL::micros() - start_time_us < SAFERTL_PRUNING_LOOP_TIME_US) {
// advance inner loop
_prune_j++;
if (_prune_j > _prune_path_points_count-2) {
_prune.j++;
if (_prune.j > _prune.path_points_count-2) {
// advance outer loop
_prune_i++;
if (_prune_i > _prune_path_points_count - 4) {
_prune_complete = true;
_prune.i++;
if (_prune.i > _prune.path_points_count - 4) {
_prune.complete = true;
return;
}
// push inner loop to start from outer loop+2 and skip over known loops
_prune_j = MAX(_prune_i + 2, _prune_j_min);
_prune.j = MAX(_prune.i + 2, _prune.j_min);
}
// find the closest distance between two line segments and the mid-point
dist_point dp = segment_segment_dist(_path[_prune_i], _path[_prune_i+1], _path[_prune_j], _path[_prune_j+1]);
dist_point dp = segment_segment_dist(_path[_prune.i], _path[_prune.i+1], _path[_prune.j], _path[_prune.j+1]);
if (dp.distance < SAFERTL_PRUNING_DELTA) { // if there is a loop here
// if the buffer is full, stop trying to prune
if (_prunable_loops_count >= _prunable_loops_max) {
_prune_complete = true;
if (_prune.loops_count >= _prune.loops_max) {
_prune.complete = true;
return;
}
// add loop to _prunable_loops array
_prunable_loops[_prunable_loops_count].start_index = _prune_i + 1;
_prunable_loops[_prunable_loops_count].end_index = _prune_j + 1;
_prunable_loops[_prunable_loops_count].midpoint = dp.midpoint;
_prunable_loops_count++;
// add loop to _prune.loops array
_prune.loops[_prune.loops_count].start_index = _prune.i + 1;
_prune.loops[_prune.loops_count].end_index = _prune.j + 1;
_prune.loops[_prune.loops_count].midpoint = dp.midpoint;
_prune.loops_count++;
// record inner loop should start no lower than 2nd segment
_prune_j_min = _prune_j + 1;
_prune.j_min = _prune.j + 1;
}
}
}
@ -578,10 +578,10 @@ void AP_SafeRTL::detect_loops()
void AP_SafeRTL::reset_if_new_points(uint16_t path_points_count)
{
// any difference in the number of points is because of new points being added to path
if (_simplify_path_points_count != path_points_count) {
if (_simplify.path_points_count != path_points_count) {
reset_simplification(path_points_count);
}
if (_prune_path_points_count != path_points_count) {
if (_prune.path_points_count != path_points_count) {
reset_pruning(path_points_count);
}
}
@ -590,29 +590,29 @@ void AP_SafeRTL::reset_if_new_points(uint16_t path_points_count)
// should be called if the existing path has been altered, for example when a loop as been removed
void AP_SafeRTL::reset_simplification(uint16_t path_points_count)
{
_simplify_complete = false;
_simplify_stack_count = 0;
_simplify_bitmask.setall();
_simplify_path_points_count = path_points_count;
_simplify.complete = false;
_simplify.stack_count = 0;
_simplify.bitmask.setall();
_simplify.path_points_count = path_points_count;
}
// reset pruning algorithm so that it will re-check all points in the path
// should be called if the existing path is altered for example when a loop as been removed
void AP_SafeRTL::reset_pruning(uint16_t path_points_count)
{
_prune_complete = false;
_prune_i = 0;
_prune_j = _prune_i+1; // detect_loops will increment this to the correct starting point of _prune_i+2.
_prune_j_min = _prune_j;
_prunable_loops_count = 0; // clear the loops that we've recorded
_prune_path_points_count = path_points_count;
_prune.complete = false;
_prune.i = 0;
_prune.j = _prune.i+1; // detect_loops will increment this to the correct starting point of _prune.i+2.
_prune.j_min = _prune.j;
_prune.loops_count = 0; // clear the loops that we've recorded
_prune.path_points_count = path_points_count;
}
// set all points that can be removed to zero
void AP_SafeRTL::zero_points_by_simplify_bitmask()
{
for (uint16_t i = 1; i < _path_points_count; i++) {
if (!_simplify_bitmask.get(i)) {
if (!_simplify.bitmask.get(i)) {
if (!_path[i].is_zero()) {
log_action(SRTL_POINT_SIMPLIFY, _path[i]);
_path[i].zero();
@ -625,8 +625,8 @@ void AP_SafeRTL::zero_points_by_simplify_bitmask()
void AP_SafeRTL::zero_points_by_loops(uint16_t points_to_delete)
{
uint16_t removed_points = 0;
for (uint16_t i = 0; i < _prunable_loops_count; i++) {
prune_loop_t l = _prunable_loops[i];
for (uint16_t i = 0; i < _prune.loops_count; i++) {
prune_loop_t l = _prune.loops[i];
for (uint16_t j = l.start_index; j < l.end_index; j++) {
// zero this point if it wasn't already zeroed
if (!_path[j].is_zero()) {

40
libraries/AP_SafeRTL/AP_SafeRTL.h
View File

@ -132,6 +132,7 @@ private:
// remove all zero points from the path
void remove_empty_points();
public:
// dist_point holds the closest distance reached between 2 line segments, and the point exactly between them
typedef struct {
float distance;
@ -140,6 +141,7 @@ private:
// get the closest distance between 2 line segments and the point midway between the closest points
static dist_point segment_segment_dist(const Vector3f& p1, const Vector3f& p2, const Vector3f& p3, const Vector3f& p4);
private:
// de-activate SafeRTL, send warning to GCS and log to dataflash
void deactivate(SRTL_Actions action, const char *reason);
@ -169,31 +171,35 @@ private:
uint16_t _path_points_count;// number of points in the path array
AP_HAL::Semaphore *_path_sem; // semaphore for updating path
// Simplify state
bool _simplify_complete;
uint16_t _simplify_path_points_count; // copy of _path_points_count taken when the simply algorithm started
// structure and buffer to hold the "to-do list" for the SIMPLIFICATION algorithm.
// Simplify
// structure and buffer to hold the "to-do list" for the simplify algorithm.
typedef struct {
uint16_t start;
uint16_t finish;
} simplify_start_finish_t;
simplify_start_finish_t* _simplify_stack;
uint16_t _simplify_stack_max; // maximum number of elements in the _simplify_stack array
uint16_t _simplify_stack_count; // number of elements in _simplify_stack array
Bitmask _simplify_bitmask = Bitmask(SAFERTL_POINTS_MAX); // simplify algorithm clears bits for each point that can be removed
struct {
bool complete;
uint16_t path_points_count; // copy of _path_points_count taken when the simply algorithm started
simplify_start_finish_t* stack;
uint16_t stack_max; // maximum number of elements in the _simplify_stack array
uint16_t stack_count; // number of elements in _simplify_stack array
Bitmask bitmask = Bitmask(SAFERTL_POINTS_MAX); // simplify algorithm clears bits for each point that can be removed
} _simplify;
// Pruning state
bool _prune_complete;
uint16_t _prune_path_points_count; // copy of _path_points_count taken when the prune algorithm started
uint16_t _prune_i; // loop search's outer loop index
uint16_t _prune_j; // loop search's inner loop index
uint16_t _prune_j_min; // inner loop search starts each iteration from no lower than this index
// Pruning
typedef struct {
uint16_t start_index;
uint16_t end_index;
Vector3f midpoint;
} prune_loop_t;
prune_loop_t* _prunable_loops; // the result of the pruning algorithm
uint16_t _prunable_loops_max; // maximum number of elements in the _prunable_loops array
uint16_t _prunable_loops_count; // number of elements in the _prunable_loops array
struct {
bool complete;
uint16_t path_points_count; // copy of _path_points_count taken when the prune algorithm started
uint16_t i; // loop search's outer loop index
uint16_t j; // loop search's inner loop index
uint16_t j_min; // inner loop search starts each iteration from no lower than this index
prune_loop_t* loops;// the result of the pruning algorithm
uint16_t loops_max; // maximum number of elements in the _prunable_loops array
uint16_t loops_count; // number of elements in the _prunable_loops array
} _prune;
};