ardupilot/APMrover2/sensors.cpp

#include "Rover.h"

#include <AP_RangeFinder/RangeFinder_Backend.h>

// initialise compass
void Rover::init_compass()
{
    if (!g.compass_enabled) {
        return;
    }

    if (!compass.init()|| !compass.read()) {
        hal.console->printf("Compass initialisation failed!\n");
        g.compass_enabled = false;
    } else {
        ahrs.set_compass(&compass);
    }
}

/*
  initialise compass's location used for declination
 */
void Rover::init_compass_location(void)
{
    // update initial location used for declination
    if (!compass_init_location) {
        Location loc;
        if (ahrs.get_position(loc)) {
            compass.set_initial_location(loc.lat, loc.lng);
            compass_init_location = true;
        }
    }
}

// init beacons used for non-gps position estimates
void Rover::init_beacon()
{
    g2.beacon.init();
}

// init visual odometry sensor
void Rover::init_visual_odom()
{
    g2.visual_odom.init();
}

// update visual odometry sensor
void Rover::update_visual_odom()
{
    // check for updates
    if (g2.visual_odom.enabled() && (g2.visual_odom.get_last_update_ms() != visual_odom_last_update_ms)) {
        visual_odom_last_update_ms = g2.visual_odom.get_last_update_ms();
        const float time_delta_sec = g2.visual_odom.get_time_delta_usec() / 1000000.0f;
        ahrs.writeBodyFrameOdom(g2.visual_odom.get_confidence(),
                                g2.visual_odom.get_position_delta(),
                                g2.visual_odom.get_angle_delta(),
                                time_delta_sec,
                                visual_odom_last_update_ms,
                                g2.visual_odom.get_pos_offset());
        // log sensor data
        DataFlash.Log_Write_VisualOdom(time_delta_sec,
                                       g2.visual_odom.get_angle_delta(),
                                       g2.visual_odom.get_position_delta(),
                                       g2.visual_odom.get_confidence());
    }
}

// update wheel encoders
void Rover::update_wheel_encoder()
{
    // exit immediately if not enabled
    if (g2.wheel_encoder.num_sensors() == 0) {
        return;
    }

    // update encoders
    g2.wheel_encoder.update();

    // initialise on first iteration
    const uint32_t now = AP_HAL::millis();
    if (wheel_encoder_last_ekf_update_ms == 0) {
        wheel_encoder_last_ekf_update_ms = now;
        for (uint8_t i = 0; i < g2.wheel_encoder.num_sensors(); i++) {
            wheel_encoder_last_angle_rad[i] = g2.wheel_encoder.get_delta_angle(i);
            wheel_encoder_last_update_ms[i] = g2.wheel_encoder.get_last_reading_ms(i);
        }
        return;
    }

    // calculate delta angle and delta time and send to EKF
    // use time of last ping from wheel encoder
    // send delta time (time between this wheel encoder time and previous wheel encoder time)
    // in case where wheel hasn't moved, count = 0 (cap the delta time at 50ms - or system time)
    //     use system clock of last update instead of time of last ping
    const float system_dt = (now - wheel_encoder_last_ekf_update_ms) / 1000.0f;
    for (uint8_t i = 0; i < g2.wheel_encoder.num_sensors(); i++) {
        // calculate angular change (in radians)
        const float curr_angle_rad = g2.wheel_encoder.get_delta_angle(i);
        const float delta_angle = curr_angle_rad - wheel_encoder_last_angle_rad[i];
        wheel_encoder_last_angle_rad[i] = curr_angle_rad;

        // calculate delta time
        float delta_time;
        const uint32_t latest_sensor_update_ms = g2.wheel_encoder.get_last_reading_ms(i);
        const uint32_t sensor_diff_ms = latest_sensor_update_ms - wheel_encoder_last_update_ms[i];

        // if we have not received any sensor updates, or time difference is too high then use time since last update to the ekf
        // check for old or insane sensor update times
        if (sensor_diff_ms == 0 || sensor_diff_ms > 100) {
            delta_time = system_dt;
            wheel_encoder_last_update_ms[i] = wheel_encoder_last_ekf_update_ms;
        } else {
            delta_time = sensor_diff_ms / 1000.0f;
            wheel_encoder_last_update_ms[i] = latest_sensor_update_ms;
        }

        /* delAng is the measured change in angular position from the previous measurement where a positive rotation is produced by forward motion of the vehicle (rad)
         * delTime is the time interval for the measurement of delAng (sec)
         * timeStamp_ms is the time when the rotation was last measured (msec)
         * posOffset is the XYZ body frame position of the wheel hub (m)
         */
        EKF3.writeWheelOdom(delta_angle, delta_time, wheel_encoder_last_update_ms[i], g2.wheel_encoder.get_position(i), g2.wheel_encoder.get_wheel_radius(i));

        // calculate rpm for reporting to GCS
        if (is_positive(delta_time)) {
            wheel_encoder_rpm[i] = (delta_angle / M_2PI) / (delta_time / 60.0f);
        } else {
            wheel_encoder_rpm[i] = 0.0f;
        }
    }

    // record system time update for next iteration
    wheel_encoder_last_ekf_update_ms = now;
}

// Calibrate compass
void Rover::compass_cal_update() {
    if (!hal.util->get_soft_armed()) {
        compass.compass_cal_update();
    }
}

// Save compass offsets
void Rover::compass_save() {
    if (g.compass_enabled &&
        compass.get_learn_type() >= Compass::LEARN_INTERNAL &&
        !arming.is_armed()) {
        compass.save_offsets();
    }
}

// Accel calibration

void Rover::accel_cal_update() {
    if (hal.util->get_soft_armed()) {
        return;
    }
    ins.acal_update();
    // check if new trim values, and set them    float trim_roll, trim_pitch;
    float trim_roll, trim_pitch;
    if (ins.get_new_trim(trim_roll, trim_pitch)) {
        ahrs.set_trim(Vector3f(trim_roll, trim_pitch, 0));
    }
}

// read the rangefinders
void Rover::read_rangefinders(void)
{
    rangefinder.update();

    AP_RangeFinder_Backend *s0 = rangefinder.get_backend(0);
    AP_RangeFinder_Backend *s1 = rangefinder.get_backend(1);

    if (s0 == nullptr || s0->status() == RangeFinder::RangeFinder_NotConnected) {
        // this makes it possible to disable rangefinder at runtime
        return;
    }

    if (s1 != nullptr && s1->has_data()) {
        // we have two rangefinders
        obstacle.rangefinder1_distance_cm = s0->distance_cm();
        obstacle.rangefinder2_distance_cm = s1->distance_cm();
        if (obstacle.rangefinder1_distance_cm < static_cast<uint16_t>(g.rangefinder_trigger_cm) &&
            obstacle.rangefinder1_distance_cm < static_cast<uint16_t>(obstacle.rangefinder2_distance_cm))  {
            // we have an object on the left
            if (obstacle.detected_count < 127) {
                obstacle.detected_count++;
            }
            if (obstacle.detected_count == g.rangefinder_debounce) {
                gcs().send_text(MAV_SEVERITY_INFO, "Rangefinder1 obstacle %u cm",
                        static_cast<uint32_t>(obstacle.rangefinder1_distance_cm));
            }
            obstacle.detected_time_ms = AP_HAL::millis();
            obstacle.turn_angle = g.rangefinder_turn_angle;
        } else if (obstacle.rangefinder2_distance_cm < static_cast<uint16_t>(g.rangefinder_trigger_cm)) {
            // we have an object on the right
            if (obstacle.detected_count < 127) {
                obstacle.detected_count++;
            }
            if (obstacle.detected_count == g.rangefinder_debounce) {
                gcs().send_text(MAV_SEVERITY_INFO, "Rangefinder2 obstacle %u cm",
                        static_cast<uint32_t>(obstacle.rangefinder2_distance_cm));
            }
            obstacle.detected_time_ms = AP_HAL::millis();
            obstacle.turn_angle = -g.rangefinder_turn_angle;
        }
    } else {
        // we have a single rangefinder
        obstacle.rangefinder1_distance_cm = s0->distance_cm();
        obstacle.rangefinder2_distance_cm = 0;
        if (obstacle.rangefinder1_distance_cm < static_cast<uint16_t>(g.rangefinder_trigger_cm))  {
            // obstacle detected in front
            if (obstacle.detected_count < 127) {
                obstacle.detected_count++;
            }
            if (obstacle.detected_count == g.rangefinder_debounce) {
                gcs().send_text(MAV_SEVERITY_INFO, "Rangefinder obstacle %u cm",
                        static_cast<uint32_t>(obstacle.rangefinder1_distance_cm));
            }
            obstacle.detected_time_ms = AP_HAL::millis();
            obstacle.turn_angle = g.rangefinder_turn_angle;
        }
    }

    Log_Write_Rangefinder();
    Log_Write_Depth();

    // no object detected - reset after the turn time
    if (obstacle.detected_count >= g.rangefinder_debounce &&
        AP_HAL::millis() > obstacle.detected_time_ms + g.rangefinder_turn_time*1000) {
        gcs().send_text(MAV_SEVERITY_INFO, "Obstacle passed");
        obstacle.detected_count = 0;
        obstacle.turn_angle = 0;
    }
}

// initialise proximity sensor
void Rover::init_proximity(void)
{
    g2.proximity.init();
    g2.proximity.set_rangefinder(&rangefinder);
}

// update error mask of sensors and subsystems. The mask
// uses the MAV_SYS_STATUS_* values from mavlink. If a bit is set
// then it indicates that the sensor or subsystem is present but
// not functioning correctly.
void Rover::update_sensor_status_flags(void)
{
    // default sensors present
    control_sensors_present = MAVLINK_SENSOR_PRESENT_DEFAULT;

    // first what sensors/controllers we have
    if (g.compass_enabled) {
        control_sensors_present |= MAV_SYS_STATUS_SENSOR_3D_MAG;  // compass present
    }
    if (gps.status() > AP_GPS::NO_GPS) {
        control_sensors_present |= MAV_SYS_STATUS_SENSOR_GPS;
    }
    if (g2.visual_odom.enabled()) {
        control_sensors_present |= MAV_SYS_STATUS_SENSOR_VISION_POSITION;
    }
    if (rover.DataFlash.logging_present()) {  // primary logging only (usually File)
        control_sensors_present |= MAV_SYS_STATUS_LOGGING;
    }
    if (rover.g2.proximity.get_status() > AP_Proximity::Proximity_NotConnected) {
        control_sensors_present |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
    }

    // all present sensors enabled by default except rate control, attitude stabilization, yaw, altitude, position control and motor output which we will set individually
    control_sensors_enabled = control_sensors_present & (~MAV_SYS_STATUS_SENSOR_ANGULAR_RATE_CONTROL &
                                                         ~MAV_SYS_STATUS_SENSOR_ATTITUDE_STABILIZATION &
                                                         ~MAV_SYS_STATUS_SENSOR_YAW_POSITION &
                                                         ~MAV_SYS_STATUS_SENSOR_XY_POSITION_CONTROL &
                                                         ~MAV_SYS_STATUS_SENSOR_MOTOR_OUTPUTS &
                                                         ~MAV_SYS_STATUS_LOGGING &
                                                         ~MAV_SYS_STATUS_SENSOR_BATTERY);
    if (control_mode->attitude_stabilized()) {
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_ANGULAR_RATE_CONTROL; // 3D angular rate control
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_ATTITUDE_STABILIZATION; // 3D angular rate control
    }
    if (control_mode->is_autopilot_mode()) {
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_YAW_POSITION; // yaw position
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_XY_POSITION_CONTROL; // X/Y position control
    }

    if (rover.DataFlash.logging_enabled()) {
        control_sensors_enabled |= MAV_SYS_STATUS_LOGGING;
    }

    // set motors outputs as enabled if safety switch is not disarmed (i.e. either NONE or ARMED)
    if (hal.util->safety_switch_state() != AP_HAL::Util::SAFETY_DISARMED) {
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_MOTOR_OUTPUTS;
    }

    if (battery.num_instances() > 0) {
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_BATTERY;
    }

    // default to all healthy except compass and gps which we set individually
    control_sensors_health = control_sensors_present & (~MAV_SYS_STATUS_SENSOR_3D_MAG & ~MAV_SYS_STATUS_SENSOR_GPS);
    if (g.compass_enabled && compass.healthy(0) && ahrs.use_compass()) {
        control_sensors_health |= MAV_SYS_STATUS_SENSOR_3D_MAG;
    }
    if (gps.is_healthy()) {
        control_sensors_health |= MAV_SYS_STATUS_SENSOR_GPS;
    }
    if (g2.visual_odom.enabled() && !g2.visual_odom.healthy()) {
        control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_VISION_POSITION;
    }
    if (!ins.get_gyro_health_all() || !ins.gyro_calibrated_ok_all()) {
        control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_3D_GYRO;
    }
    if (!ins.get_accel_health_all()) {
        control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_3D_ACCEL;
    }

    if (ahrs.initialised() && !ahrs.healthy()) {
        // AHRS subsystem is unhealthy
        control_sensors_health &= ~MAV_SYS_STATUS_AHRS;
    }

    if (rangefinder.num_sensors() > 0) {
        control_sensors_present |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
        control_sensors_enabled |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
        AP_RangeFinder_Backend *s = rangefinder.get_backend(0);
        if (s != nullptr && s->has_data()) {
            control_sensors_health |= MAV_SYS_STATUS_SENSOR_LASER_POSITION;
        }
    }
    if (rover.g2.proximity.get_status() == AP_Proximity::Proximity_NoData) {
        control_sensors_health &= ~MAV_SYS_STATUS_SENSOR_LASER_POSITION;
    }
    if (rover.DataFlash.logging_failed()) {
        control_sensors_health &= ~MAV_SYS_STATUS_LOGGING;
    }

    if (!battery.healthy() || battery.has_failsafed()) {
        control_sensors_enabled &= ~MAV_SYS_STATUS_SENSOR_BATTERY;
    }

    if (!initialised || ins.calibrating()) {
        // while initialising the gyros and accels are not enabled
        control_sensors_enabled &= ~(MAV_SYS_STATUS_SENSOR_3D_GYRO | MAV_SYS_STATUS_SENSOR_3D_ACCEL);
        control_sensors_health &= ~(MAV_SYS_STATUS_SENSOR_3D_GYRO | MAV_SYS_STATUS_SENSOR_3D_ACCEL);
    }
#if FRSKY_TELEM_ENABLED == ENABLED
    // give mask of error flags to Frsky_Telemetry
    frsky_telemetry.update_sensor_status_flags(~control_sensors_health & control_sensors_enabled & control_sensors_present);
#endif
}