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AC_PrecLand: non functional changes including adding comments

This commit is contained in:
Randy Mackay 2017-03-16 17:01:16 +09:00
parent 2a29d7fedd
commit 1fb6d468c6
2 changed files with 33 additions and 27 deletions
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16
libraries/AC_PrecLand/AC_PrecLand.cpp
View File

@ -52,8 +52,8 @@ const AP_Param::GroupInfo AC_PrecLand::var_info[] = {
// @Param: EST_TYPE
// @DisplayName: Precision Land Estimator Type
// @Description: Specifies the estimation method used.
// @Values: 0:RAW_MEASUREMENTS, 1:TWO_STATE_KF_PER_AXIS
// @Description: Specifies the estimation method to be used
// @Values: 0:RawSensor, 1:KalmanFilter
// @User: Advanced
AP_GROUPINFO("EST_TYPE", 5, AC_PrecLand, _estimator_type, 1),
@ -81,7 +81,6 @@ AC_PrecLand::AC_PrecLand(const AP_AHRS& ahrs, const AP_InertialNav& inav) :
_backend_state.healthy = false;
}
// init - perform any required initialisation of backends
void AC_PrecLand::init()
{
@ -129,14 +128,15 @@ void AC_PrecLand::init()
// update - give chance to driver to get updates from sensor
void AC_PrecLand::update(float rangefinder_alt_cm, bool rangefinder_alt_valid)
{
// Collect inertial data and append it to the buffer
// append current velocity and attitude correction into history buffer
struct inertial_data_frame_s inertial_data_newest;
_ahrs.getCorrectedDeltaVelocityNED(inertial_data_newest.correctedVehicleDeltaVelocityNED, inertial_data_newest.dt);
inertial_data_newest.Tbn = _ahrs.get_rotation_body_to_ned();
inertial_data_newest.inertialNavVelocity = _inav.get_velocity()*0.01f;
inertial_data_newest.inertialNavVelocityValid = _inav.get_filter_status().flags.horiz_vel;
_inertial_history.push_back(inertial_data_newest);
// update estimator of target position
if (_backend != nullptr && _enabled) {
_backend->update();
run_estimator(rangefinder_alt_cm*0.01f, rangefinder_alt_valid);
@ -195,7 +195,7 @@ void AC_PrecLand::run_estimator(float rangefinder_alt_m, bool rangefinder_alt_va
const struct inertial_data_frame_s& inertial_data_delayed = _inertial_history.front();
switch (_estimator_type) {
case ESTIMATOR_TYPE_RAW_MEASUREMENTS: {
case ESTIMATOR_TYPE_RAW_SENSOR: {
// Return if there's any invalid velocity data
for (uint8_t i=0; i<_inertial_history.size(); i++) {
const struct inertial_data_frame_s& inertial_data = _inertial_history.peek(i);
@ -245,7 +245,7 @@ void AC_PrecLand::run_estimator(float rangefinder_alt_m, bool rangefinder_alt_va
}
break;
}
case ESTIMATOR_TYPE_TWO_STATE_KF_PER_AXIS: {
case ESTIMATOR_TYPE_KALMAN_FILTER: {
// Predict
if (target_acquired()) {
const float& dt = inertial_data_delayed.dt;
@ -349,7 +349,7 @@ void AC_PrecLand::run_output_prediction()
_target_pos_rel_out_NE.y += _target_vel_rel_out_NE.y * inertial_data.dt;
}
// Apply offset
// compensate for camera offset from the center of the vehicle
Vector3f land_ofs_ned_m = _ahrs.get_rotation_body_to_ned() * Vector3f(_land_ofs_cm_x,_land_ofs_cm_y,0) * 0.01f;
_target_pos_rel_out_NE.x += land_ofs_ned_m.x;
_target_pos_rel_out_NE.y += land_ofs_ned_m.y;

44
libraries/AC_PrecLand/AC_PrecLand.h
View File

@ -51,13 +51,16 @@ public:
// returns true if precision landing is healthy
bool healthy() const { return _backend_state.healthy; }
// returns true if precision landing is enabled (used only for logging)
bool enabled() const { return _enabled.get(); }
// returns time of last update
uint32_t last_update_ms() const { return _last_update_ms; }
// give chance to driver to get updates from sensor
// give chance to driver to get updates from sensor, should be called at 400hz
void update(float rangefinder_alt_cm, bool rangefinder_alt_valid);
// returns target position relative to origin
// returns target position relative to the EKF origin
bool get_target_position_cm(Vector2f& ret);
// returns target position relative to vehicle
@ -72,23 +75,26 @@ public:
// process a LANDING_TARGET mavlink message
void handle_msg(mavlink_message_t* msg);
// accessors for logging
bool enabled() const { return _enabled; }
// parameter var table
static const struct AP_Param::GroupInfo var_info[];
private:
enum estimator_type_t {
ESTIMATOR_TYPE_RAW_MEASUREMENTS=0,
ESTIMATOR_TYPE_TWO_STATE_KF_PER_AXIS=1
ESTIMATOR_TYPE_RAW_SENSOR = 0,
ESTIMATOR_TYPE_KALMAN_FILTER = 1
};
// returns enabled parameter as an behaviour
enum PrecLandBehaviour get_behaviour() const { return (enum PrecLandBehaviour)(_enabled.get()); }
// run target position estimator
void run_estimator(float rangefinder_alt_m, bool rangefinder_alt_valid);
// get vehicle body frame 3D vector from vehicle to target. returns true on success, false on failure
bool retrieve_los_meas(Vector3f& target_vec_unit_body);
// calculate target's position and velocity relative to the vehicle (used as input to position controller)
// results are stored in_target_pos_rel_out_NE, _target_vel_rel_out_NE
void run_output_prediction();
// references to inertial nav and ahrs libraries
@ -103,29 +109,29 @@ private:
AP_Float _land_ofs_cm_x; // Desired landing position of the camera forward of the target in vehicle body frame
AP_Float _land_ofs_cm_y; // Desired landing position of the camera right of the target in vehicle body frame
uint32_t _last_update_ms; // epoch time in millisecond when update is called
bool _target_acquired;
uint32_t _last_backend_los_meas_ms;
uint32_t _last_update_ms; // system time in millisecond when update was last called
bool _target_acquired; // true if target has been seen recently
uint32_t _last_backend_los_meas_ms; // system time target was last seen
PosVelEKF _ekf_x, _ekf_y;
uint32_t _outlier_reject_count;
PosVelEKF _ekf_x, _ekf_y; // Kalman Filter for x and y axis
uint32_t _outlier_reject_count; // mini-EKF's outlier counter (3 consecutive outliers lead to EKF accepting updates)
Vector3f _target_pos_rel_meas_NED;
Vector3f _target_pos_rel_meas_NED; // target's relative position as 3D vector
Vector2f _target_pos_rel_est_NE;
Vector2f _target_vel_rel_est_NE;
Vector2f _target_pos_rel_est_NE; // target's relative position based on latest sensor data (i.e. not compensated for lag)
Vector2f _target_vel_rel_est_NE; // target's relative velocity based on latest sensor data (i.e. not compensated for lag)
Vector2f _target_pos_rel_out_NE;
Vector2f _target_vel_rel_out_NE;
Vector2f _target_pos_rel_out_NE; // target's relative position, fed into position controller
Vector2f _target_vel_rel_out_NE; // target's relative velocity, fed into position controller
// structure and buffer to hold a short history of vehicle velocity
struct inertial_data_frame_s {
Matrix3f Tbn;
Matrix3f Tbn; // dcm rotation matrix to rotate body frame to north
Vector3f correctedVehicleDeltaVelocityNED;
Vector3f inertialNavVelocity;
bool inertialNavVelocityValid;
float dt;
};
AP_Buffer<inertial_data_frame_s,8> _inertial_history;
// backend state