// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- // update_navigation - checks for new GPS updates and invokes navigation routines static void update_navigation() { static uint32_t nav_last_gps_update = 0; // the system time of the last gps update static uint32_t nav_last_gps_time = 0; // the time according to the gps bool pos_updated = false; bool log_output = false; // check for new gps data if( g_gps->fix && g_gps->time != nav_last_gps_time ) { // used to calculate speed in X and Y, iterms // ------------------------------------------ dTnav = (float)(millis() - nav_last_gps_update)/ 1000.0; nav_last_gps_update = millis(); // prevent runup from bad GPS dTnav = min(dTnav, 1.0); // save GPS time nav_last_gps_time = g_gps->time; // signal to run nav controllers pos_updated = true; // signal to create log entry log_output = true; } #if INERTIAL_NAV_XY == ENABLED // TO-DO: clean this up because inertial nav is overwriting the dTnav and pos_updated from above // check for inertial nav updates if( inertial_nav.position_ok() ) { // 50hz dTnav = 0.02; // To-Do: calculate the time from the mainloop or INS readings? // signal to run nav controllers pos_updated = true; } #endif // calc various navigation values and run controllers if we've received a position update if( pos_updated ) { // calculate velocity calc_velocity_and_position(); // calculate distance, angles to target calc_distance_and_bearing(); // run navigation controllers run_navigation_contollers(); // Rotate the nav_lon and nav_lat vectors based on Yaw calc_nav_pitch_roll(); // update log if (log_output && (g.log_bitmask & MASK_LOG_NTUN) && motors.armed()) { Log_Write_Nav_Tuning(); } } // reduce nav outputs to zero if we have not received a gps update in 2 seconds if( millis() - nav_last_gps_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; } } //******************************************************************************************************* // calc_velocity_and_filtered_position - velocity in lon and lat directions calculated from GPS position // and accelerometer data // lon_speed expressed in cm/s. positive numbers mean moving east // lat_speed expressed in cm/s. positive numbers when moving north // Note: we use gps locations directly to calculate velocity instead of asking gps for velocity because // this is more accurate below 1.5m/s // Note: even though the positions are projected using a lead filter, the velocities are calculated // from the unaltered gps locations. We do not want noise from our lead filter affecting velocity //******************************************************************************************************* static void calc_velocity_and_position(){ static int32_t last_gps_longitude = 0; static int32_t last_gps_latitude = 0; // initialise last_longitude and last_latitude if( last_gps_longitude == 0 && last_gps_latitude == 0 ) { last_gps_longitude = g_gps->longitude; last_gps_latitude = g_gps->latitude; } // this speed is ~ in cm because we are using 10^7 numbers from GPS float tmp = 1.0/dTnav; #if INERTIAL_NAV_XY == ENABLED if( inertial_nav.position_ok() ) { // pull velocity from interial nav library lon_speed = inertial_nav.get_longitude_velocity(); lat_speed = inertial_nav.get_latitude_velocity(); // pull position from interial nav library current_loc.lng = inertial_nav.get_longitude(); current_loc.lat = inertial_nav.get_latitude(); }else{ // calculate velocity lon_speed = (float)(g_gps->longitude - last_gps_longitude) * scaleLongDown * tmp; lat_speed = (float)(g_gps->latitude - last_gps_latitude) * tmp; // calculate position from gps + expected travel during gps_lag current_loc.lng = xLeadFilter.get_position(g_gps->longitude, lon_speed, g_gps->get_lag()); current_loc.lat = yLeadFilter.get_position(g_gps->latitude, lat_speed, g_gps->get_lag()); } #else // calculate velocity lon_speed = (float)(g_gps->longitude - last_gps_longitude) * scaleLongDown * tmp; lat_speed = (float)(g_gps->latitude - last_gps_latitude) * tmp; // calculate position from gps + expected travel during gps_lag current_loc.lng = xLeadFilter.get_position(g_gps->longitude, lon_speed, g_gps->get_lag()); current_loc.lat = yLeadFilter.get_position(g_gps->latitude, lat_speed, g_gps->get_lag()); #endif // store gps lat and lon values for next iteration last_gps_longitude = g_gps->longitude; last_gps_latitude = g_gps->latitude; } //**************************************************************** // Function that will calculate the desired direction to fly and distance //**************************************************************** static void calc_distance_and_bearing() { // waypoint distance from plane in cm // --------------------------------------- wp_distance = get_distance_cm(¤t_loc, &next_WP); home_distance = get_distance_cm(¤t_loc, &home); // wp_bearing is bearing to next waypoint // -------------------------------------------- wp_bearing = get_bearing_cd(¤t_loc, &next_WP); home_bearing = get_bearing_cd(¤t_loc, &home); // bearing to target (used when yaw_mode = YAW_LOOK_AT_LOCATION) yaw_look_at_WP_bearing = get_bearing_cd(¤t_loc, &yaw_look_at_WP); } static void calc_location_error(struct Location *next_loc) { /* * Becuase we are using lat and lon to do our distance errors here's a quick chart: * 100 = 1m * 1000 = 11m = 36 feet * 1800 = 19.80m = 60 feet * 3000 = 33m * 10000 = 111m */ // X Error long_error = (float)(next_loc->lng - current_loc.lng) * scaleLongDown; // 500 - 0 = 500 Go East // Y Error lat_error = next_loc->lat - current_loc.lat; // 500 - 0 = 500 Go North } // called after a GPS read static void run_navigation_contollers() { // wp_distance is in CM // -------------------- switch(control_mode) { case AUTO: // note: wp_control is handled by commands_logic verify_commands(); // calculates the desired Roll and Pitch update_nav_wp(); break; case GUIDED: wp_control = WP_MODE; // check if we are close to point > loiter wp_verify_byte = 0; verify_nav_wp(); if (wp_control != WP_MODE) { set_mode(LOITER); } update_nav_wp(); break; case RTL: // execute the RTL state machine verify_RTL(); // calculates the desired Roll and Pitch update_nav_wp(); break; // switch passthrough to LOITER case LOITER: case POSITION: // This feature allows us to reposition the quad when the user lets // go of the sticks if((abs(g.rc_2.control_in) + abs(g.rc_1.control_in)) > 500) { if(wp_distance > 500){ ap.loiter_override = true; } } // Allow the user to take control temporarily, if(ap.loiter_override) { // this sets the copter to not try and nav while we control it wp_control = NO_NAV_MODE; // reset LOITER to current position next_WP.lat = current_loc.lat; next_WP.lng = current_loc.lng; if(g.rc_2.control_in == 0 && g.rc_1.control_in == 0) { wp_control = LOITER_MODE; ap.loiter_override = false; } }else{ wp_control = LOITER_MODE; } // calculates the desired Roll and Pitch update_nav_wp(); break; case LAND: verify_land(); // calculates the desired Roll and Pitch update_nav_wp(); break; case CIRCLE: wp_control = CIRCLE_MODE; update_nav_wp(); break; case STABILIZE: case TOY_A: case TOY_M: wp_control = NO_NAV_MODE; update_nav_wp(); break; } // are we in SIMPLE mode? if(ap.simple_mode && g.super_simple) { // get distance to home if(home_distance > SUPER_SIMPLE_RADIUS) { // 10m from home // we reset the angular offset to be a vector from home to the quad initial_simple_bearing = wrap_360(home_bearing+18000); //cliSerial->printf("ISB: %d\n", initial_simple_bearing); } } } // update_nav_wp - high level calculation of nav_lat and nav_lon based on wp_control // called after gps read from run_navigation_controller static void update_nav_wp() { int16_t loiter_delta; int16_t speed; switch( wp_control ) { case LOITER_MODE: // calc error to target calc_location_error(&next_WP); // use error as the desired rate towards the target calc_loiter(long_error, lat_error); break; case CIRCLE_MODE: // check if we have missed the WP loiter_delta = (wp_bearing - old_wp_bearing)/100; // reset the old value old_wp_bearing = wp_bearing; // wrap values if (loiter_delta > 180) loiter_delta -= 360; if (loiter_delta < -180) loiter_delta += 360; // sum the angle around the WP loiter_sum += loiter_delta; circle_angle += (circle_rate * dTnav); //1deg = 0.0174532925 radians // wrap if (circle_angle > 6.28318531) circle_angle -= 6.28318531; next_WP.lng = circle_WP.lng + (g.circle_radius * 100 * cos(1.57 - circle_angle) * scaleLongUp); next_WP.lat = circle_WP.lat + (g.circle_radius * 100 * sin(1.57 - circle_angle)); // use error as the desired rate towards the target // nav_lon, nav_lat is calculated if(wp_distance > 400) { calc_nav_rate(get_desired_speed(g.waypoint_speed_max)); }else{ // calc the lat and long error to the target calc_location_error(&next_WP); calc_loiter(long_error, lat_error); } break; case WP_MODE: // calc error to target calc_location_error(&next_WP); speed = get_desired_speed(g.waypoint_speed_max); // use error as the desired rate towards the target calc_nav_rate(speed); break; case NO_NAV_MODE: // clear out our nav so we can do things like land straight down // or change Loiter position // We bring copy over our Iterms for wind control, but we don't navigate nav_lon = g.pid_loiter_rate_lon.get_integrator(); nav_lat = g.pid_loiter_rate_lon.get_integrator(); nav_lon = constrain(nav_lon, -2000, 2000); // 20m nav_lat = constrain(nav_lat, -2000, 2000); // 20m 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 100 degrees } #define NAV_ERR_MAX 600 #define NAV_RATE_ERR_MAX 250 static void calc_loiter(int16_t x_error, int16_t y_error) { int32_t p,i,d; // used to capture pid values for logging int32_t output; int32_t x_target_speed, y_target_speed; // East / West x_target_speed = g.pi_loiter_lon.get_p(x_error); // calculate desired speed from lon error #if LOGGING_ENABLED == ENABLED // log output if PID logging is on and we are tuning the yaw if( g.log_bitmask & MASK_LOG_PID && (g.radio_tuning == CH6_LOITER_KP || g.radio_tuning == CH6_LOITER_KI) ) { Log_Write_PID(CH6_LOITER_KP, x_error, x_target_speed, 0, 0, x_target_speed, tuning_value); } #endif // calculate rate error x_rate_error = x_target_speed - lon_speed; // calc the speed error p = g.pid_loiter_rate_lon.get_p(x_rate_error); i = g.pid_loiter_rate_lon.get_i(x_rate_error + x_error, dTnav); d = g.pid_loiter_rate_lon.get_d(x_error, dTnav); d = constrain(d, -2000, 2000); // get rid of noise if(abs(lon_speed) < 50) { d = 0; } output = p + i + d; nav_lon = constrain(output, -32000, 32000); // constraint to remove chance of overflow when adding int32_t to int16_t #if LOGGING_ENABLED == ENABLED // log output if PID logging is on and we are tuning the yaw if( g.log_bitmask & MASK_LOG_PID && (g.radio_tuning == CH6_LOITER_RATE_KP || g.radio_tuning == CH6_LOITER_RATE_KI || g.radio_tuning == CH6_LOITER_RATE_KD) ) { Log_Write_PID(CH6_LOITER_RATE_KP, x_rate_error, p, i, d, nav_lon, tuning_value); } #endif // North / South y_target_speed = g.pi_loiter_lat.get_p(y_error); // calculate desired speed from lat error #if LOGGING_ENABLED == ENABLED // log output if PID logging is on and we are tuning the yaw if( g.log_bitmask & MASK_LOG_PID && (g.radio_tuning == CH6_LOITER_KP || g.radio_tuning == CH6_LOITER_KI) ) { Log_Write_PID(CH6_LOITER_KP+100, y_error, y_target_speed, 0, 0, y_target_speed, tuning_value); } #endif // calculate rate error y_rate_error = y_target_speed - lat_speed; // calc the speed error p = g.pid_loiter_rate_lat.get_p(y_rate_error); i = g.pid_loiter_rate_lat.get_i(y_rate_error + y_error, dTnav); d = g.pid_loiter_rate_lat.get_d(y_error, dTnav); d = constrain(d, -2000, 2000); // get rid of noise if(abs(lat_speed) < 50) { d = 0; } output = p + i + d; nav_lat = constrain(output, -32000, 32000); // constraint to remove chance of overflow when adding int32_t to int16_t #if LOGGING_ENABLED == ENABLED // log output if PID logging is on and we are tuning the yaw if( g.log_bitmask & MASK_LOG_PID && (g.radio_tuning == CH6_LOITER_RATE_KP || g.radio_tuning == CH6_LOITER_RATE_KI || g.radio_tuning == CH6_LOITER_RATE_KD) ) { Log_Write_PID(CH6_LOITER_RATE_KP+100, y_rate_error, p, i, d, nav_lat, tuning_value); } #endif // copy over I term to Nav_Rate g.pid_nav_lon.set_integrator(g.pid_loiter_rate_lon.get_integrator()); g.pid_nav_lat.set_integrator(g.pid_loiter_rate_lat.get_integrator()); } static void calc_nav_rate(int16_t max_speed) { float temp, temp_x, temp_y; // push us towards the original track update_crosstrack(); int16_t cross_speed = crosstrack_error * -g.crosstrack_gain; // scale down crosstrack_error in cm cross_speed = constrain(cross_speed, -150, 150); // rotate by 90 to deal with trig functions temp = (9000l - wp_bearing) * RADX100; temp_x = cos(temp); temp_y = sin(temp); // rotate desired spped vector: int32_t x_target_speed = max_speed * temp_x - cross_speed * temp_y; int32_t y_target_speed = cross_speed * temp_x + max_speed * temp_y; // East / West // calculate rate error x_rate_error = x_target_speed - lon_speed; x_rate_error = constrain(x_rate_error, -500, 500); nav_lon = g.pid_nav_lon.get_pid(x_rate_error, dTnav); int32_t tilt = (x_target_speed * x_target_speed * (int32_t)g.tilt_comp) / 10000; if(x_target_speed < 0) tilt = -tilt; nav_lon += tilt; // North / South // calculate rate error y_rate_error = y_target_speed - lat_speed; y_rate_error = constrain(y_rate_error, -500, 500); // added a rate error limit to keep pitching down to a minimum nav_lat = g.pid_nav_lat.get_pid(y_rate_error, dTnav); tilt = (y_target_speed * y_target_speed * (int32_t)g.tilt_comp) / 10000; if(y_target_speed < 0) tilt = -tilt; nav_lat += tilt; // copy over I term to Loiter_Rate g.pid_loiter_rate_lon.set_integrator(g.pid_nav_lon.get_integrator()); g.pid_loiter_rate_lat.set_integrator(g.pid_nav_lat.get_integrator()); } // this calculation rotates our World frame of reference to the copter's frame of reference // We use the DCM's matrix to precalculate these trig values at 50hz static void calc_nav_pitch_roll() { //cliSerial->printf("ys %ld, cx %1.4f, _cx %1.4f | sy %1.4f, _sy %1.4f\n", dcm.yaw_sensor, cos_yaw_x, _cos_yaw_x, sin_yaw_y, _sin_yaw_y); // rotate the vector auto_roll = (float)nav_lon * sin_yaw_y - (float)nav_lat * cos_yaw_x; auto_pitch = (float)nav_lon * cos_yaw_x + (float)nav_lat * sin_yaw_y; // flip pitch because forward is negative auto_pitch = -auto_pitch; } static int16_t get_desired_speed(int16_t max_speed) { /* Based on Equation by Bill Premerlani & Robert Lefebvre (sq(V2)-sq(V1))/2 = A(X2-X1) derives to: V1 = sqrt(sq(V2) - 2*A*(X2-X1)) */ if(ap.fast_corner) { // don't slow down }else{ if(wp_distance < 20000){ // limit the size of numbers we're dealing with to avoid overflow // go slower int32_t temp = 2 * 100 * (int32_t)(wp_distance - g.waypoint_radius * 100); int32_t s_min = WAYPOINT_SPEED_MIN; temp += s_min * s_min; max_speed = sqrt((float)temp); max_speed = min(max_speed, g.waypoint_speed_max); } } max_speed = min(max_speed, max_speed_old + (100 * dTnav));// limit going faster max_speed = max(max_speed, WAYPOINT_SPEED_MIN); // don't go too slow max_speed_old = max_speed; return max_speed; } static void reset_desired_speed() { max_speed_old = 0; } static void update_crosstrack(void) { // Crosstrack Error // ---------------- if (wp_distance >= (g.crosstrack_min_distance * 100) && abs(wrap_180(wp_bearing - original_wp_bearing)) < 4500) { float temp = (wp_bearing - original_wp_bearing) * RADX100; crosstrack_error = sin(temp) * wp_distance; // Meters we are off track line }else{ // fade out crosstrack crosstrack_error >>= 1; } } 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) { 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); } } 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) { // always start Circle mode at same angle circle_angle = 0; // 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 new command, used by loiter long_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)); }