// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- // update_navigation - invokes navigation routines // called at 10hz static void update_navigation() { static uint32_t nav_last_update = 0; // the system time of the last time nav was run update // check for inertial nav updates if( inertial_nav.position_ok() ) { // calculate time since nav controllers last ran dTnav = (float)(millis() - nav_last_update)/ 1000.0f; nav_last_update = millis(); // prevent runnup in dTnav value dTnav = min(dTnav, 1.0f); // run the navigation controllers update_nav_mode(); // update log if (g.log_bitmask & MASK_LOG_NTUN && motors.armed()) { Log_Write_Nav_Tuning(); } } // To-Do: replace below with proper GPS failsafe // reduce nav outputs to zero if we have not seen a position update in 2 seconds if( millis() - nav_last_update > 2000 ) { // after 12 reads we guess we may have lost GPS signal, stop navigating // we have lost GPS signal for a moment. Reduce our error to avoid flyaways auto_roll >>= 1; auto_pitch >>= 1; } } // run_nav_updates - top level call for the autopilot // ensures calculations such as "distance to waypoint" are calculated before autopilot makes decisions // To-Do - rename and move this function to make it's purpose more clear static void run_nav_updates(void) { // fetch position from inertial navigation calc_position(); // check altitude vs target verify_altitude(); // calculate distance and bearing for reporting and autopilot decisions calc_distance_and_bearing(); // run autopilot to make high level decisions about control modes run_autopilot(); } // calc_position - get lat and lon positions from inertial nav library static void calc_position(){ if( inertial_nav.position_ok() ) { // pull position from interial nav library current_loc.lng = inertial_nav.get_longitude(); current_loc.lat = inertial_nav.get_latitude(); } } // calc_distance_and_bearing - calculate distance and direction to waypoints for reporting and autopilot decisions static void calc_distance_and_bearing() { // get current position Vector2f curr_pos(inertial_nav.get_latitude_diff(), inertial_nav.get_longitude_diff()); Vector2f dest; // get target from loiter or wpinav controller if( nav_mode == NAV_LOITER || nav_mode == NAV_CIRCLE ) { dest.x = loiter_lat_from_home_cm; dest.y = loiter_lon_from_home_cm; }else if( nav_mode == NAV_WP ) { dest.x = wpinav_destination.x; dest.y = wpinav_destination.y; }else{ dest = curr_pos; } // calculate distance to target lat_error = dest.x - curr_pos.x; lon_error = dest.y - curr_pos.y; wp_distance = safe_sqrt(lat_error*lat_error+lon_error*lon_error); // calculate waypoint bearing // To-Do: change this to more efficient calculation if( waypoint_valid(next_WP) ) { wp_bearing = get_bearing_cd(¤t_loc, &next_WP); }else{ wp_bearing = 0; } // calculate home distance and bearing if( ap.home_is_set ) { home_distance = safe_sqrt(curr_pos.x*curr_pos.x + curr_pos.y*curr_pos.y); // To-Do: change this to more efficient calculation home_bearing = get_bearing_cd(¤t_loc, &home); // update super simple bearing (if required) because it relies on home_bearing update_super_simple_bearing(); }else{ home_distance = 0; home_bearing = 0; } // calculate bearing to target (used when yaw_mode = YAW_LOOK_AT_LOCATION) // To-Do: move this to the look-at-waypoint yaw controller if( waypoint_valid(yaw_look_at_WP) ) { yaw_look_at_WP_bearing = get_bearing_cd(¤t_loc, &yaw_look_at_WP); } } // run_autopilot - highest level call to process mission commands static void run_autopilot() { switch( control_mode ) { case AUTO: // majority of command logic is in commands_logic.pde verify_commands(); break; case GUIDED: // switch to loiter once we've reached the target location and altitude if(verify_nav_wp()) { set_nav_mode(NAV_LOITER); } case RTL: verify_RTL(); break; } } // set_nav_mode - update nav mode and initialise any variables as required static bool set_nav_mode(uint8_t new_nav_mode) { // boolean to ensure proper initialisation of nav modes bool nav_initialised = false; // return immediately if no change if( new_nav_mode == nav_mode ) { return true; } switch( new_nav_mode ) { case NAV_NONE: nav_initialised = true; break; case NAV_CIRCLE: // set center of circle to current position circle_set_center(Vector2f(inertial_nav.get_latitude_diff(), inertial_nav.get_longitude_diff()), ahrs.yaw); nav_initialised = true; break; case NAV_LOITER: // set target to current position loiter_set_target(inertial_nav.get_latitude_diff(), inertial_nav.get_longitude_diff()); nav_initialised = true; break; case NAV_WP: nav_initialised = true; break; } // if initialisation has been successful update the yaw mode if( nav_initialised ) { nav_mode = new_nav_mode; } // return success or failure return nav_initialised; } // update_nav_mode - run navigation controller based on nav_mode static void update_nav_mode() { switch( nav_mode ) { case NAV_NONE: // do nothing break; case NAV_CIRCLE: // call circle controller which in turn calls loiter controller circle_get_pos(dTnav); break; case NAV_LOITER: get_loiter_pos_lat_lon(loiter_lat_from_home_cm, loiter_lon_from_home_cm, 0.1f); break; case NAV_WP: // move forward on the waypoint // To-Do: slew up the speed to the max waypoint speed instead of immediately jumping to max wpinav_advance_track_desired(g.waypoint_speed_max, dTnav); // run the navigation controller get_wpinav_pos(dTnav); break; } /* // To-Do: check that we haven't broken toy mode case TOY_A: case TOY_M: set_nav_mode(NAV_NONE); update_nav_wp(); break; } */ } static bool check_missed_wp() { int32_t temp; temp = wp_bearing - original_wp_bearing; temp = wrap_180(temp); return (labs(temp) > 9000); // we passed the waypoint by 90 degrees } static void force_new_altitude(int32_t new_alt) { next_WP.alt = new_alt; set_alt_change(REACHED_ALT); } static void set_new_altitude(int32_t new_alt) { // if no change exit immediately if(new_alt == next_WP.alt) { return; } // update new target altitude next_WP.alt = new_alt; if(next_WP.alt > (current_loc.alt + 80)) { // we are below, going up set_alt_change(ASCENDING); }else if(next_WP.alt < (current_loc.alt - 80)) { // we are above, going down set_alt_change(DESCENDING); }else{ // No Change set_alt_change(REACHED_ALT); } } // verify_altitude - check if we have reached the target altitude static void verify_altitude() { if(alt_change_flag == ASCENDING) { // we are below, going up if(current_loc.alt > next_WP.alt - 50) { set_alt_change(REACHED_ALT); } }else if (alt_change_flag == DESCENDING) { // we are above, going down if(current_loc.alt <= next_WP.alt + 50){ set_alt_change(REACHED_ALT); } } } // Keeps old data out of our calculation / logs static void reset_nav_params(void) { // We must be heading to a new WP, so XTrack must be 0 crosstrack_error = 0; // Will be set by new command wp_bearing = 0; // Will be set by new command wp_distance = 0; // Will be set by nav or loiter controllers lon_error = 0; lat_error = 0; nav_lon = 0; nav_lat = 0; nav_roll = 0; nav_pitch = 0; auto_roll = 0; auto_pitch = 0; } static int32_t wrap_360(int32_t error) { if (error > 36000) error -= 36000; if (error < 0) error += 36000; return error; } static int32_t wrap_180(int32_t error) { if (error > 18000) error -= 36000; if (error < -18000) error += 36000; return error; } // get_yaw_slew - reduces rate of change of yaw to a maximum // assumes it is called at 100hz so centi-degrees and update rate cancel each other out static int32_t get_yaw_slew(int32_t current_yaw, int32_t desired_yaw, int16_t deg_per_sec) { return wrap_360(current_yaw + constrain(wrap_180(desired_yaw - current_yaw), -deg_per_sec, deg_per_sec)); } // valid_waypoint - checks if a waypoint has been initialised or not static bool waypoint_valid(Location &wp) { if( wp.lat != 0 || wp.lng != 0 ) { return true; }else{ return false; } } //////////////////////////////////////////////////// // Loiter controller using inertial nav //////////////////////////////////////////////////// // get_loiter_accel - loiter acceration controllers with desired accelerations provided in forward/right directions in cm/s/s static void get_loiter_accel(int16_t accel_req_forward, int16_t accel_req_right) { float z_accel_meas = -AP_INTERTIALNAV_GRAVITY * 100; // gravity in cm/s/s // update angle targets that will be passed to stabilize controller auto_roll = constrain((accel_req_right/(-z_accel_meas))*(18000/M_PI), -4500, 4500); auto_pitch = constrain((-accel_req_forward/(-z_accel_meas*cos_roll_x))*(18000/M_PI), -4500, 4500); } // get_loiter_accel_lat_lon - loiter acceration controller with desired accelerations provided in lat/lon directions in cm/s/s static void get_loiter_accel_lat_lon(int16_t accel_lat, int16_t accel_lon) { float accel_forward; float accel_right; accel_forward = accel_lat*cos_yaw + accel_lon*sin_yaw; accel_right = -accel_lat*sin_yaw + accel_lon*cos_yaw; get_loiter_accel(accel_forward, accel_right); } // get_loiter_vel_lat_lon - loiter velocity controller with desired velocity provided in lat/lon directions in cm/s #define MAX_LOITER_VEL_ACCEL 400 // should be 1.5 times larger than MAX_LOITER_POS_ACCEL static void get_loiter_vel_lat_lon(int16_t vel_lat, int16_t vel_lon, float dt) { float speed_error_lat = 0; // The velocity in cm/s. float speed_error_lon = 0; // The velocity in cm/s. float speed_lat = inertial_nav.get_latitude_velocity(); float speed_lon = inertial_nav.get_longitude_velocity(); int32_t accel_lat; int32_t accel_lon; int32_t accel_total; int16_t lat_p,lat_i,lat_d; int16_t lon_p,lon_i,lon_d; // calculate vel error speed_error_lat = vel_lat - speed_lat; speed_error_lon = vel_lon - speed_lon; lat_p = g.pid_loiter_rate_lat.get_p(speed_error_lat); lat_i = g.pid_loiter_rate_lat.get_i(speed_error_lat, dt); lat_d = g.pid_loiter_rate_lat.get_d(speed_error_lat, dt); lon_p = g.pid_loiter_rate_lon.get_p(speed_error_lon); lon_i = g.pid_loiter_rate_lon.get_i(speed_error_lon, dt); lon_d = g.pid_loiter_rate_lon.get_d(speed_error_lon, dt); accel_lat = (lat_p+lat_i+lat_d); accel_lon = (lon_p+lon_i+lon_d); accel_total = safe_sqrt(accel_lat*accel_lat + accel_lon*accel_lon); if( accel_total > MAX_LOITER_VEL_ACCEL ) { accel_lat = MAX_LOITER_VEL_ACCEL * accel_lat/accel_total; accel_lon = MAX_LOITER_VEL_ACCEL * accel_lon/accel_total; } get_loiter_accel_lat_lon(accel_lat, accel_lon); } // get_loiter_pos_lat_lon - loiter position controller with desired position provided as distance from home in lat/lon directions in cm #define MAX_LOITER_POS_VELOCITY 750 // should be 1.5 ~ 2.0 times the pilot input's max velocity #define MAX_LOITER_POS_ACCEL 250 static void get_loiter_pos_lat_lon(int32_t target_lat_from_home, int32_t target_lon_from_home, float dt) { float dist_error_lat; int32_t desired_vel_lat; float dist_error_lon; int32_t desired_vel_lon; int32_t dist_error_total; int16_t vel_sqrt; int32_t vel_total; int16_t linear_distance; // the distace we swap between linear and sqrt. // calculate distance error dist_error_lat = target_lat_from_home - inertial_nav.get_latitude_diff(); dist_error_lon = target_lon_from_home - inertial_nav.get_longitude_diff(); linear_distance = MAX_LOITER_POS_ACCEL/(2*g.pi_loiter_lat.kP()*g.pi_loiter_lat.kP()); dist_error_total = safe_sqrt(dist_error_lat*dist_error_lat + dist_error_lon*dist_error_lon); if( dist_error_total > 2*linear_distance ) { vel_sqrt = constrain(safe_sqrt(2*MAX_LOITER_POS_ACCEL*(dist_error_total-linear_distance)),0,1000); desired_vel_lat = vel_sqrt * dist_error_lat/dist_error_total; desired_vel_lon = vel_sqrt * dist_error_lon/dist_error_total; }else{ desired_vel_lat = g.pi_loiter_lat.get_p(dist_error_lat); desired_vel_lon = g.pi_loiter_lon.get_p(dist_error_lon); } vel_total = safe_sqrt(desired_vel_lat*desired_vel_lat + desired_vel_lon*desired_vel_lon); if( vel_total > MAX_LOITER_POS_VELOCITY ) { desired_vel_lat = MAX_LOITER_POS_VELOCITY * desired_vel_lat/vel_total; desired_vel_lon = MAX_LOITER_POS_VELOCITY * desired_vel_lon/vel_total; } get_loiter_vel_lat_lon(desired_vel_lat, desired_vel_lon, dt); } #define MAX_LOITER_POS_VEL_VELOCITY 1000 // loiter_set_pos_from_velocity - loiter velocity controller with desired velocity provided in front/right directions in cm/s static void loiter_set_pos_from_velocity(int16_t vel_forward_cms, int16_t vel_right_cms, float dt) { int32_t vel_lat; int32_t vel_lon; int32_t vel_total; vel_lat = vel_forward_cms*cos_yaw - vel_right_cms*sin_yaw; vel_lon = vel_forward_cms*sin_yaw + vel_right_cms*cos_yaw; // constrain the velocity vector and scale if necessary vel_total = safe_sqrt(vel_lat*vel_lat + vel_lon*vel_lon); if( vel_total > MAX_LOITER_POS_VEL_VELOCITY ) { vel_lat = MAX_LOITER_POS_VEL_VELOCITY * vel_lat/vel_total; vel_lon = MAX_LOITER_POS_VEL_VELOCITY * vel_lon/vel_total; } // update loiter target position loiter_lat_from_home_cm += vel_lat * dt; loiter_lon_from_home_cm += vel_lon * dt; // update next_WP location for reporting purposes set_next_WP_latlon( home.lat + loiter_lat_from_home_cm / LATLON_TO_CM, home.lng + loiter_lat_from_home_cm / LATLON_TO_CM * scaleLongUp); } // loiter_set_target - set loiter's target position from home in cm // To-Do: change this function to accept a target in lat/lon format (and remove setting of next_WP?) static void loiter_set_target(float lat_from_home_cm, float lon_from_home_cm) { loiter_lat_from_home_cm = lat_from_home_cm; loiter_lon_from_home_cm = lon_from_home_cm; // update next_WP location for reporting purposes set_next_WP_latlon( home.lat + loiter_lat_from_home_cm / LATLON_TO_CM, home.lng + loiter_lat_from_home_cm / LATLON_TO_CM * scaleLongUp); } ////////////////////////////////////////////////////////// // waypoint inertial navigation controller ////////////////////////////////////////////////////////// // Waypoint navigation is accomplished by moving the target location up to a maximum of 10m from the current location // get_wpinav_pos - wpinav position controller with desired position held in wpinav_destination static void get_wpinav_pos(float dt) { // re-use loiter position controller get_loiter_pos_lat_lon(wpinav_target.x, wpinav_target.y, dt); } // wpinav_set_destination - set destination using lat/lon coordinates void wpinav_set_destination(const Location& destination) { wpinav_set_origin_and_destination(current_loc, destination); } // wpinav_set_origin_and_destination - set origin and destination using lat/lon coordinates void wpinav_set_origin_and_destination(const Location& origin, const Location& destination) { wpinav_origin.x = (origin.lat-home.lat) * LATLON_TO_CM; wpinav_origin.y = (origin.lng-home.lng) * LATLON_TO_CM * scaleLongDown; wpinav_destination.x = (destination.lat-home.lat) * LATLON_TO_CM; wpinav_destination.y = (destination.lng-home.lng) * LATLON_TO_CM * scaleLongDown; wpinav_pos_delta = wpinav_destination - wpinav_origin; wpinav_track_length = wpinav_pos_delta.length(); wpinav_track_desired = 0; // set next_WP, prev_WP for reporting purposes // To-Do: move calcs below to a function set_next_WP_latlon( home.lat + wpinav_destination.x / LATLON_TO_CM, home.lng + wpinav_destination.y / LATLON_TO_CM * scaleLongUp); } #define WPINAV_MAX_POS_ERROR 2000.0f // maximum distance (in cm) that the desired track can stray from our current location. void wpinav_advance_track_desired(float velocity_cms, float dt) { float cross_track_dist; float track_covered; float track_desired_max; float line_a, line_b, line_c, line_m; // get current location Vector2f curr(inertial_nav.get_latitude_diff(), inertial_nav.get_longitude_diff()); // check for zero length segment if( wpinav_pos_delta.x == 0 && wpinav_pos_delta.y == 0) { wpinav_target = wpinav_destination; return; } if( wpinav_pos_delta.x == 0 ) { // x is zero cross_track_dist = fabs(curr.x - wpinav_destination.x); track_covered = fabs(curr.y - wpinav_origin.y); }else if(wpinav_pos_delta.y == 0) { // y is zero cross_track_dist = fabs(curr.y - wpinav_destination.y); track_covered = fabs(curr.x - wpinav_origin.x); }else{ // both x and y non zero line_a = wpinav_pos_delta.y; line_b = -wpinav_pos_delta.x; line_c = wpinav_pos_delta.x * wpinav_origin.y - wpinav_pos_delta.y * wpinav_origin.x; line_m = line_a / line_b; cross_track_dist = abs(line_a * curr.x + line_b * curr.y + line_c ) / wpinav_track_length; line_m = 1/line_m; line_a = line_m; line_b = -1; line_c = curr.y - line_m * curr.x; // calculate the distance to the closest point along the track and it's distance from the origin track_covered = abs(line_a*wpinav_origin.x + line_b*wpinav_origin.y + line_c) / safe_sqrt(line_a*line_a+line_b*line_b); } // maximum distance along the track that we will allow (stops target point from getting too far from the current position) track_desired_max = track_covered + safe_sqrt(WPINAV_MAX_POS_ERROR*WPINAV_MAX_POS_ERROR-cross_track_dist*cross_track_dist); // advance the current target wpinav_track_desired += velocity_cms * dt; // constrain the target from moving too far if( wpinav_track_desired > track_desired_max ) { wpinav_track_desired = track_desired_max; } if( wpinav_track_desired > wpinav_track_length ) { wpinav_track_desired = wpinav_track_length; } // recalculate the desired position float track_length_pct = wpinav_track_desired/wpinav_track_length; wpinav_target.x = wpinav_origin.x + wpinav_pos_delta.x * track_length_pct; wpinav_target.y = wpinav_origin.y + wpinav_pos_delta.y * track_length_pct; } ////////////////////////////////////////////////////////// // circle navigation controller ////////////////////////////////////////////////////////// // circle_set_center -- set circle controller's center position and starting angle static void circle_set_center(const Vector2f pos_vec, float heading_in_radians) { // set circle center circle_center = pos_vec; // set starting angle to current heading - 180 degrees circle_angle = heading_in_radians-ToRad(180); if( circle_angle > 180 ) { circle_angle -= 180; } if( circle_angle < -180 ) { circle_angle -= 180; } // initialise other variables circle_angle_total = 0; } // circle_get_pos - circle position controller's main call which in turn calls loiter controller with updated target position static void circle_get_pos(float dt) { float angle_delta = circle_rate * dt; float cir_radius = g.circle_radius * 100; Vector2f circle_target; // update the target angle circle_angle += angle_delta; if( circle_angle > 180 ) { circle_angle -= 360; } if( circle_angle <= -180 ) { circle_angle += 360; } // update the total angle travelled circle_angle_total += angle_delta; // calculate target position circle_target.x = circle_center.x + cir_radius * sinf(1.57f - circle_angle); circle_target.y = circle_center.y + cir_radius * cosf(1.57f - circle_angle); // re-use loiter position controller get_loiter_pos_lat_lon(circle_target.x, circle_target.y, dt); }