Copter: add comments to RTL's compute return target

This commit is contained in:
Randy Mackay 2016-07-04 15:54:51 +09:00
parent 68d3655195
commit 5255f55cc3
1 changed files with 6 additions and 2 deletions

View File

@ -422,7 +422,7 @@ void Copter::rtl_build_path(bool terrain_following_allowed)
// return target's altitude is updated to a higher altitude that the vehicle can safely return at (frame may also be set) // return target's altitude is updated to a higher altitude that the vehicle can safely return at (frame may also be set)
void Copter::rtl_compute_return_target(bool terrain_following_allowed) void Copter::rtl_compute_return_target(bool terrain_following_allowed)
{ {
// set return target to nearest rally point or home position // set return target to nearest rally point or home position (Note: alt is absolute)
#if AC_RALLY == ENABLED #if AC_RALLY == ENABLED
rtl_path.return_target = rally.calc_best_rally_or_home_location(current_loc, ahrs.get_home().alt); rtl_path.return_target = rally.calc_best_rally_or_home_location(current_loc, ahrs.get_home().alt);
#else #else
@ -445,7 +445,7 @@ void Copter::rtl_compute_return_target(bool terrain_following_allowed)
} }
} }
// convert return-target alt to alt-above-home or alt-above-terrain // convert return-target alt (which is an absolute alt) to alt-above-home or alt-above-terrain
if (!rtl_path.terrain_used || !rtl_path.return_target.change_alt_frame(Location_Class::ALT_FRAME_ABOVE_TERRAIN)) { if (!rtl_path.terrain_used || !rtl_path.return_target.change_alt_frame(Location_Class::ALT_FRAME_ABOVE_TERRAIN)) {
if (!rtl_path.return_target.change_alt_frame(Location_Class::ALT_FRAME_ABOVE_HOME)) { if (!rtl_path.return_target.change_alt_frame(Location_Class::ALT_FRAME_ABOVE_HOME)) {
// this should never happen but just in case // this should never happen but just in case
@ -475,6 +475,10 @@ void Copter::rtl_compute_return_target(bool terrain_following_allowed)
#if AC_FENCE == ENABLED #if AC_FENCE == ENABLED
// ensure not above fence altitude if alt fence is enabled // ensure not above fence altitude if alt fence is enabled
// Note: because the rtl_path.climb_target's altitude is simply copied from the return_target's altitude,
// if terrain altitudes are being used, the code below which reduces the return_target's altitude can lead to
// the vehicle not climbing at all as RTL begins. This can be overly conservative and it might be better
// to apply the fence alt limit independently on the origin_point and return_target
if ((fence.get_enabled_fences() & AC_FENCE_TYPE_ALT_MAX) != 0) { if ((fence.get_enabled_fences() & AC_FENCE_TYPE_ALT_MAX) != 0) {
// get return target as alt-above-home so it can be compared to fence's alt // get return target as alt-above-home so it can be compared to fence's alt
if (rtl_path.return_target.get_alt_cm(Location_Class::ALT_FRAME_ABOVE_HOME, target_alt)) { if (rtl_path.return_target.get_alt_cm(Location_Class::ALT_FRAME_ABOVE_HOME, target_alt)) {