From 4532eca4ef6f6170765062ccd2ca7f29814e0b3a Mon Sep 17 00:00:00 2001 From: Lorenz Meier Date: Tue, 15 Oct 2013 22:55:16 +0200 Subject: Covered corner case in L1 controller not adressed so far in existing concepts --- src/lib/ecl/l1/ecl_l1_pos_controller.cpp | 33 ++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) (limited to 'src/lib') diff --git a/src/lib/ecl/l1/ecl_l1_pos_controller.cpp b/src/lib/ecl/l1/ecl_l1_pos_controller.cpp index c5c0c7a3c..daf136d49 100644 --- a/src/lib/ecl/l1/ecl_l1_pos_controller.cpp +++ b/src/lib/ecl/l1/ecl_l1_pos_controller.cpp @@ -130,8 +130,12 @@ void ECL_L1_Pos_Controller::navigate_waypoints(const math::Vector2f &vector_A, c float alongTrackDist = vector_A_to_airplane * vector_AB; /* estimate airplane position WRT to B */ - math::Vector2f vector_B_to_airplane_unit = get_local_planar_vector(vector_B, vector_curr_position).normalized(); - float bearing_wp_b = atan2f(-vector_B_to_airplane_unit.getY() , -vector_B_to_airplane_unit.getX()); + math::Vector2f vector_B_to_P_unit = get_local_planar_vector(vector_B, vector_curr_position).normalized(); + + /* calculate angle of airplane position vector relative to line) */ + + // XXX this could probably also be based solely on the dot product + float AB_to_BP_bearing = atan2f(vector_B_to_P_unit % vector_AB, vector_B_to_P_unit * vector_AB); /* extension from [2], fly directly to A */ if (distance_A_to_airplane > _L1_distance && alongTrackDist / math::max(distance_A_to_airplane , 1.0f) < -0.7071f) { @@ -148,21 +152,30 @@ void ECL_L1_Pos_Controller::navigate_waypoints(const math::Vector2f &vector_A, c /* bearing from current position to L1 point */ _nav_bearing = atan2f(-vector_A_to_airplane_unit.getY() , -vector_A_to_airplane_unit.getX()); -// XXX this can be useful as last-resort guard, but is currently not needed -#if 0 - } else if (absf(bearing_wp_b) > math::radians(80.0f)) { - /* extension, fly back to waypoint */ + /* + * If the AB vector and the vector from B to airplane point in the same + * direction, we have missed the waypoint. At +- 90 degrees we are just passing it. + */ + } else if (fabsf(AB_to_BP_bearing) < math::radians(100.0f)) { + /* + * Extension, fly back to waypoint. + * + * This corner case is possible if the system was following + * the AB line from waypoint A to waypoint B, then is + * switched to manual mode (or otherwise misses the waypoint) + * and behind the waypoint continues to follow the AB line. + */ /* calculate eta to fly to waypoint B */ /* velocity across / orthogonal to line */ - xtrack_vel = ground_speed_vector % (-vector_B_to_airplane_unit); + xtrack_vel = ground_speed_vector % (-vector_B_to_P_unit); /* velocity along line */ - ltrack_vel = ground_speed_vector * (-vector_B_to_airplane_unit); + ltrack_vel = ground_speed_vector * (-vector_B_to_P_unit); eta = atan2f(xtrack_vel, ltrack_vel); /* bearing from current position to L1 point */ - _nav_bearing = bearing_wp_b; -#endif + _nav_bearing = atan2f(-vector_B_to_P_unit.getY() , -vector_B_to_P_unit.getX()); + } else { /* calculate eta to fly along the line between A and B */ -- cgit v1.2.3