ardupilot/ArduCopter/navigation.pde

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// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
//****************************************************************
// Function that will calculate the desired direction to fly and distance
//****************************************************************
static byte navigate()
{
// waypoint distance from plane in cm
// ---------------------------------------
wp_distance = get_distance(&current_loc, &next_WP);
home_distance = get_distance(&current_loc, &home);
if (wp_distance < 0){
// something went very wrong
return 0;
}
// target_bearing is where we should be heading
// --------------------------------------------
target_bearing = get_bearing(&current_loc, &next_WP);
home_to_copter_bearing = get_bearing(&home, &current_loc);
// nav_bearing will includes xtrac correction
// ------------------------------------------
nav_bearing = target_bearing;
return 1;
}
static bool check_missed_wp()
{
int32_t temp;
temp = target_bearing - original_target_bearing;
temp = wrap_180(temp);
return (abs(temp) > 10000); // we passed the waypoint by 100 degrees
}
// ------------------------------
static void calc_XY_velocity(){
// offset calculation of GPS speed:
// used for estimations below 1.5m/s
// our GPS is about 1m per
static int32_t last_longitude = 0;
static int32_t last_latitude = 0;
static int16_t x_speed_old = 0;
static int16_t y_speed_old = 0;
// y_GPS_speed positve = Up
// x_GPS_speed positve = Right
// initialise last_longitude and last_latitude
if( last_longitude == 0 && last_latitude == 0 ) {
last_longitude = g_gps->longitude;
last_latitude = g_gps->latitude;
}
// this speed is ~ in cm because we are using 10^7 numbers from GPS
float tmp = 1.0/dTnav;
x_actual_speed = (float)(g_gps->longitude - last_longitude) * scaleLongDown * tmp;
y_actual_speed = (float)(g_gps->latitude - last_latitude) * tmp;
x_actual_speed = (x_actual_speed + x_speed_old ) / 2;
y_actual_speed = (y_actual_speed + y_speed_old ) / 2;
x_speed_old = x_actual_speed;
y_speed_old = y_actual_speed;
last_longitude = g_gps->longitude;
last_latitude = g_gps->latitude;
/*if(g_gps->ground_speed > 150){
float temp = radians((float)g_gps->ground_course/100.0);
x_actual_speed = (float)g_gps->ground_speed * sin(temp);
y_actual_speed = (float)g_gps->ground_speed * cos(temp);
}*/
}
static void calc_location_error(struct Location *next_loc)
{
static int16_t last_lon_error = 0;
static int16_t last_lat_error = 0;
static int16_t last_lon_d = 0;
static int16_t last_lat_d = 0;
/*
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
int16_t tmp;
// -------------------------------------
tmp = (long_error - last_lon_error);
if(abs(abs(tmp) -last_lon_d) > 20){
tmp = x_rate_d;
}/*
if(long_error > 0){
if(tmp < 0) tmp = 0;
}else{
if(tmp > 0) tmp = 0;
}*/
x_rate_d = lon_rate_d_filter.apply(tmp);
x_rate_d = constrain(x_rate_d, -800, 800);
last_lon_d = abs(tmp);
// -------------------------------------
tmp = (lat_error - last_lat_error);
if(abs(abs(tmp) -last_lat_d) > 20)
tmp = y_rate_d;
/*if(lat_error > 0){
if(tmp < 0) tmp = 0;
}else{
if(tmp > 0) tmp = 0;
}*/
y_rate_d = lat_rate_d_filter.apply(tmp);
y_rate_d = constrain(y_rate_d, -800, 800);
last_lat_d = abs(tmp);
// debug
//int16_t t22 = x_rate_d * (g.pid_loiter_rate_lon.kD() / dTnav);
//if(control_mode == LOITER)
// Serial.printf("XX, %d, %d, %d \n", long_error, t22, (int16_t)g.pid_loiter_rate_lon.get_integrator());
last_lon_error = long_error;
last_lat_error = lat_error;
}
#define NAV_ERR_MAX 600
#define NAV_RATE_ERR_MAX 250
static void calc_loiter(int x_error, int 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
x_rate_error = x_target_speed - x_actual_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(x_actual_speed) < 50){
d = 0;
}
output = p + i + d;
nav_lon = constrain(output, -3000, 3000); // 30°
#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
y_rate_error = y_target_speed - y_actual_speed;
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(y_actual_speed) < 50){
d = 0;
}
output = p + i + d;
nav_lat = constrain(output, -3000, 3000); // 30°
#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());
//Serial.printf("XX, %d, %d, %d\n", long_error, x_actual_speed, (int16_t)g.pid_loiter_rate_lon.get_integrator());
// Wind I term based on location error,
// limit windup
/*
int16_t x_iterm, y_iterm;
x_error = constrain(x_error, -NAV_ERR_MAX, NAV_ERR_MAX);
y_error = constrain(y_error, -NAV_ERR_MAX, NAV_ERR_MAX);
x_iterm = g.pi_loiter_lon.get_i(x_error, dTnav);
y_iterm = g.pi_loiter_lat.get_i(y_error, dTnav);
nav_lat = nav_lat + y_iterm;
nav_lon = nav_lon + x_iterm;
*/
/*
int8_t ttt = 1.0/dTnav;
int16_t t2 = g.pi_nav_lat.get_integrator();
// 1 2 3 4 5 6 7 8 9 10
Serial.printf("%d, %d, %d, %d, %d, %d, %d, %d, %d, %d\n",
wp_distance, //1
y_error, //2
y_GPS_speed, //3
y_actual_speed, //4 ;
y_target_speed, //5
y_rate_error, //6
nav_lat_p, //7
nav_lat, //8
y_iterm, //9
t2); //10
//*/
/*
int16_t t1 = g.pid_nav_lon.get_integrator(); // X
Serial.printf("%d, %1.4f, %d, %d, %d, %d, %d, %d, %d, %d\n",
wp_distance, //1
dTnav, //2
x_error, //3
x_GPS_speed, //4
x_actual_speed, //5
x_target_speed, //6
x_rate_error, //7
nav_lat, //8
x_iterm, //9
t1); //10
//*/
}
static void calc_nav_rate(int max_speed)
{
// push us towards the original track
update_crosstrack();
// nav_bearing includes crosstrack
float temp = (9000l - nav_bearing) * RADX100;
// East / West
x_rate_error = (cos(temp) * max_speed) - x_actual_speed; // 413
x_rate_error = constrain(x_rate_error, -1000, 1000);
nav_lon = g.pid_nav_lon.get_pid(x_rate_error, dTnav);
nav_lon = constrain(nav_lon, -3000, 3000);
// North / South
y_rate_error = (sin(temp) * max_speed) - y_actual_speed; // 413
y_rate_error = constrain(y_rate_error, -1000, 1000); // added a rate error limit to keep pitching down to a minimum
nav_lat = g.pid_nav_lat.get_pid(y_rate_error, dTnav);
nav_lat = constrain(nav_lat, -3000, 3000);
// 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());
//int16_t x_iterm = g.pi_loiter_lon.get_i(x_rate_error, dTnav);
//int16_t y_iterm = g.pi_loiter_lat.get_i(y_rate_error, dTnav);
//nav_lon = nav_lon + x_iterm;
//nav_lat = nav_lat + y_iterm;
/*
Serial.printf("max_sp %d,\t x_sp %d, y_sp %d,\t x_re: %d, y_re: %d, \tnav_lon: %d, nav_lat: %d, Xi:%d, Yi:%d, \t XE %d \n",
max_speed,
x_actual_speed,
y_actual_speed,
x_rate_error,
y_rate_error,
nav_lon,
nav_lat,
x_iterm,
y_iterm,
crosstrack_error);
//*/
// nav_lat and nav_lon will be rotated to the angle of the quad in calc_nav_pitch_roll()
/*Serial.printf("max_speed: %d, xspeed: %d, yspeed: %d, x_re: %d, y_re: %d, nav_lon: %ld, nav_lat: %ld ",
max_speed,
x_actual_speed,
y_actual_speed,
x_rate_error,
y_rate_error,
nav_lon,
nav_lat);*/
}
/*static void calc_nav_lon(int rate)
{
nav_lon = g.pid_nav_lon.get_pid(rate, dTnav);
nav_lon = constrain(nav_lon, -3000, 3000);
}
static void calc_nav_lat(int rate)
{
nav_lat = g.pid_nav_lat.get_pid(rate, dTnav);
nav_lat = constrain(nav_lat, -3000, 3000);
}
*/
//static int16_t get_corrected_angle(int16_t desired_rate, int16_t rate_out)
/*{
int16_t tt = desired_rate;
// scale down the desired rate and square it
desired_rate = desired_rate / 20;
desired_rate = desired_rate * desired_rate;
int16_t tmp = 0;
if (tt > 0){
tmp = rate_out + (rate_out - desired_rate);
tmp = max(tmp, rate_out);
}else if (tt < 0){
tmp = rate_out + (rate_out + desired_rate);
tmp = min(tmp, rate_out);
}
//Serial.printf("rate:%d, norm:%d, out:%d \n", tt, rate_out, tmp);
return tmp;
}*/
//wp_distance,ttt, y_error, y_GPS_speed, y_actual_speed, y_target_speed, y_rate_error, nav_lat, y_iterm, t2
// 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_loiter_pitch_roll()
{
//Serial.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 calc_desired_speed(int16_t max_speed, bool _slow)
{
/*
|< WP Radius
0 1 2 3 4 5 6 7 8m
...|...|...|...|...|...|...|...|
100 | 200 300 400cm/s
| +|+
|< we should slow to 1.5 m/s as we hit the target
*/
// max_speed is default 600 or 6m/s
if(_slow){
max_speed = min(max_speed, wp_distance / 2);
max_speed = max(max_speed, 0);
}else{
max_speed = min(max_speed, wp_distance);
max_speed = max(max_speed, WAYPOINT_SPEED_MIN); // go at least 100cm/s
}
// limit the ramp up of the speed
// waypoint_speed_gov is reset to 0 at each new WP command
if(max_speed > waypoint_speed_gov){
waypoint_speed_gov += (int)(100.0 * dTnav); // increase at .5/ms
max_speed = waypoint_speed_gov;
}
return max_speed;
}
static void update_crosstrack(void)
{
// Crosstrack Error
// ----------------
if (abs(wrap_180(target_bearing - original_target_bearing)) < 4500) { // If we are too far off or too close we don't do track following
float temp = (target_bearing - original_target_bearing) * RADX100;
crosstrack_error = sin(temp) * (wp_distance * g.crosstrack_gain); // Meters we are off track line
nav_bearing = target_bearing + constrain(crosstrack_error, -3000, 3000);
nav_bearing = wrap_360(nav_bearing);
}else{
nav_bearing = target_bearing;
}
}
static int32_t get_altitude_error()
{
// Next_WP alt is our target alt
// It changes based on climb rate
// until it reaches the target_altitude
return next_WP.alt - current_loc.alt;
}
static void clear_new_altitude()
{
alt_change_flag = REACHED_ALT;
}
static void force_new_altitude(int32_t _new_alt)
{
next_WP.alt = _new_alt;
target_altitude = _new_alt;
alt_change_flag = REACHED_ALT;
}
static void set_new_altitude(int32_t _new_alt)
{
if(_new_alt == current_loc.alt){
force_new_altitude(_new_alt);
return;
}
// We start at the current location altitude and gradually change alt
next_WP.alt = current_loc.alt;
// for calculating the delta time
alt_change_timer = millis();
// save the target altitude
target_altitude = _new_alt;
// reset our altitude integrator
alt_change = 0;
// save the original altitude
original_altitude = current_loc.alt;
// to decide if we have reached the target altitude
if(target_altitude > original_altitude){
// we are below, going up
alt_change_flag = ASCENDING;
//Serial.printf("go up\n");
}else if(target_altitude < original_altitude){
// we are above, going down
alt_change_flag = DESCENDING;
//Serial.printf("go down\n");
}else{
// No Change
alt_change_flag = REACHED_ALT;
//Serial.printf("reached alt\n");
}
//Serial.printf("new alt: %d Org alt: %d\n", target_altitude, original_altitude);
}
static int32_t get_new_altitude()
{
// returns a new next_WP.alt
if(alt_change_flag == ASCENDING){
// we are below, going up
if(current_loc.alt >= target_altitude){
alt_change_flag = REACHED_ALT;
}
// we shouldn't command past our target
if(next_WP.alt >= target_altitude){
return target_altitude;
}
}else if (alt_change_flag == DESCENDING){
// we are above, going down
if(current_loc.alt <= target_altitude)
alt_change_flag = REACHED_ALT;
// we shouldn't command past our target
if(next_WP.alt <= target_altitude){
return target_altitude;
}
}
// if we have reached our target altitude, return the target alt
if(alt_change_flag == REACHED_ALT){
return target_altitude;
}
int32_t diff = abs(next_WP.alt - target_altitude);
// scale is how we generate a desired rate from the elapsed time
// a smaller scale means faster rates
int8_t _scale = 4;
if (next_WP.alt < target_altitude){
// we are below the target alt
if(diff < 200){
_scale = 4;
} else {
_scale = 3;
}
}else {
// we are above the target, going down
if(diff < 400){
_scale = 5;
}
if(diff < 100){
_scale = 6;
}
}
// we use the elapsed time as our altitude offset
// 1000 = 1 sec
// 1000 >> 4 = 64cm/s descent by default
int32_t change = (millis() - alt_change_timer) >> _scale;
if(alt_change_flag == ASCENDING){
alt_change += change;
}else{
alt_change -= change;
}
// for generating delta time
alt_change_timer = millis();
return original_altitude + alt_change;
}
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;
}
/*
//static int32_t get_altitude_above_home(void)
{
// This is the altitude above the home location
// The GPS gives us altitude at Sea Level
// if you slope soar, you should see a negative number sometimes
// -------------------------------------------------------------
return current_loc.alt - home.alt;
}
*/
// distance is returned in cm
static int32_t get_distance(struct Location *loc1, struct Location *loc2)
{
float dlat = (float)(loc2->lat - loc1->lat);
float dlong = ((float)(loc2->lng - loc1->lng)) * scaleLongDown;
dlong = sqrt(sq(dlat) + sq(dlong)) * 1.113195;
return dlong;
}
/*
//static int32_t get_alt_distance(struct Location *loc1, struct Location *loc2)
{
return abs(loc1->alt - loc2->alt);
}
*/
static int32_t get_bearing(struct Location *loc1, struct Location *loc2)
{
int32_t off_x = loc2->lng - loc1->lng;
int32_t off_y = (loc2->lat - loc1->lat) * scaleLongUp;
int32_t bearing = 9000 + atan2(-off_y, off_x) * 5729.57795;
if (bearing < 0) bearing += 36000;
return bearing;
}