FlightTask.hpp

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/**
 * @file FlightTask.hpp
 *
 * Abstract base class for different advanced flight tasks like orbit, follow me, ...
 *
 * @author Matthias Grob <maetugr@gmail.com>
 */

#pragma once

#include <px4_platform_common/module_params.h>
#include <drivers/drv_hrt.h>
#include <matrix/matrix/math.hpp>
#include <uORB/Subscription.hpp>
#include <uORB/topics/landing_gear.h>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>
#include <uORB/topics/vehicle_command.h>
#include <uORB/topics/vehicle_constraints.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/vehicle_trajectory_waypoint.h>
#include <lib/weather_vane/WeatherVane.hpp>

class FlightTask : public ModuleParams
{
public:
    FlightTask() :
        ModuleParams(nullptr)
    {
        _resetSetpoints();
        _constraints = empty_constraints;
    }

    virtual ~FlightTask() = default;

    /**
     * Call once on the event where you switch to the task
     * @param state of the previous task
     * @return true on success, false on error
     */
    virtual bool activate(vehicle_local_position_setpoint_s last_setpoint);

    /**
     * Call this to reset an active Flight Task
     */
    virtual void reActivate();

    /**
     * To be called to adopt parameters from an arrived vehicle command
     * @param command received command message containing the parameters
     * @return true if accepted, false if declined
     */
    virtual bool applyCommandParameters(const vehicle_command_s &command) { return false; }

    /**
     * Call before activate() or update()
     * to initialize time and input data
     * @return true on success, false on error
     */
    virtual bool updateInitialize();

    /**
     * To be called regularly in the control loop cycle to execute the task
     * @return true on success, false on error
     */
    virtual bool update() = 0;

    /**
     * Call after update()
     * to constrain the generated setpoints in order to comply
     * with the constraints of the current mode
     * @return true on success, false on error
     */
    virtual bool updateFinalize() { return true; };

    /**
     * Get the output data
     * @return task output setpoints that get executed by the positon controller
     */
    const vehicle_local_position_setpoint_s getPositionSetpoint();

    /**
     * Get vehicle constraints.
     * The constraints can vary with task.
     * @return constraints
     */
    const vehicle_constraints_s &getConstraints() { return _constraints; }

    /**
     * Get landing gear position.
     * The constraints can vary with task.
     * @return landing gear
     */
    const landing_gear_s &getGear() { return _gear; }

    /**
     * Get avoidance desired waypoint
     * @return desired waypoints
     */
    const vehicle_trajectory_waypoint_s &getAvoidanceWaypoint() { return _desired_waypoint; }

    /**
     * Empty setpoint.
     * All setpoints are set to NAN.
     */
    static const vehicle_local_position_setpoint_s empty_setpoint;

    /**
     * Empty constraints.
     * All constraints are set to NAN.
     */
    static const vehicle_constraints_s empty_constraints;

    /**
     * default landing gear state
     */
    static const landing_gear_s empty_landing_gear_default_keep;

    /**
     * Call this whenever a parameter update notification is received (parameter_update uORB message)
     */
    void handleParameterUpdate()
    {
        updateParams();
    }

    /**
     * Sets an external yaw handler which can be used by any flight task to implement a different yaw control strategy.
     * This method does nothing, each flighttask which wants to use the yaw handler needs to override this method.
     */
    virtual void setYawHandler(WeatherVane *ext_yaw_handler) {}

    void updateVelocityControllerIO(const matrix::Vector3f &vel_sp,
                    const matrix::Vector3f &thrust_sp) {_velocity_setpoint_feedback = vel_sp; _thrust_setpoint_feedback = thrust_sp; }

protected:

    uORB::SubscriptionData<vehicle_local_position_s>    _sub_vehicle_local_position{ORB_ID(vehicle_local_position)};
    uORB::SubscriptionData<vehicle_attitude_s>      _sub_attitude{ORB_ID(vehicle_attitude)};

    /** Reset all setpoints to NAN */
    void _resetSetpoints();

    /** Check and update local position */
    void _evaluateVehicleLocalPosition();

    /** Set constraints to default values */
    virtual void _setDefaultConstraints();

    /** Determine when to trigger a takeoff (ignored in flight) */
    virtual bool _checkTakeoff();

    /**
     * Monitor the EKF reset counters and
     * call the appropriate handling functions in case of a reset event
     */
    void _initEkfResetCounters();
    void _checkEkfResetCounters();
    virtual void _ekfResetHandlerPositionXY() {};
    virtual void _ekfResetHandlerVelocityXY() {};
    virtual void _ekfResetHandlerPositionZ() {};
    virtual void _ekfResetHandlerVelocityZ() {};
    virtual void _ekfResetHandlerHeading(float delta_psi) {};

    /* Time abstraction */
    static constexpr uint64_t _timeout = 500000; /**< maximal time in us before a loop or data times out */
    float _time = 0; /**< passed time in seconds since the task was activated */
    float _deltatime = 0; /**< passed time in seconds since the task was last updated */
    hrt_abstime _time_stamp_activate = 0; /**< time stamp when task was activated */
    hrt_abstime _time_stamp_current = 0; /**< time stamp at the beginning of the current task update */
    hrt_abstime _time_stamp_last = 0; /**< time stamp when task was last updated */

    /* Current vehicle state */
    matrix::Vector3f _position; /**< current vehicle position */
    matrix::Vector3f _velocity; /**< current vehicle velocity */
    float _yaw = 0.f; /**< current vehicle yaw heading */
    float _dist_to_bottom = 0.0f; /**< current height above ground level */

    /**
     * Setpoints which the position controller has to execute.
     * Setpoints that are set to NAN are not controlled. Not all setpoints can be set at the same time.
     * If more than one type of setpoint is set, then order of control is a as follow: position, velocity,
     * acceleration, thrust. The exception is _position_setpoint together with _velocity_setpoint, where the
     * _velocity_setpoint is used as feedforward.
     * _acceleration_setpoint and _jerk_setpoint are currently not supported.
     */
    matrix::Vector3f _position_setpoint;
    matrix::Vector3f _velocity_setpoint;
    matrix::Vector3f _acceleration_setpoint;
    matrix::Vector3f _jerk_setpoint;
    matrix::Vector3f _thrust_setpoint;
    float _yaw_setpoint;
    float _yawspeed_setpoint;

    matrix::Vector3f _velocity_setpoint_feedback;
    matrix::Vector3f _thrust_setpoint_feedback;

    /* Counters for estimator local position resets */
    struct {
        uint8_t xy = 0;
        uint8_t vxy = 0;
        uint8_t z = 0;
        uint8_t vz = 0;
        uint8_t quat = 0;
    } _reset_counters;

    /**
     * Vehicle constraints.
     * The constraints can vary with tasks.
     */
    vehicle_constraints_s _constraints{};

    landing_gear_s _gear{};

    /**
     * Desired waypoints.
     * Goals set by the FCU to be sent to the obstacle avoidance system.
     */
    vehicle_trajectory_waypoint_s _desired_waypoint{};

    DEFINE_PARAMETERS_CUSTOM_PARENT(ModuleParams,
                    (ParamFloat<px4::params::MPC_XY_VEL_MAX>) _param_mpc_xy_vel_max,
                    (ParamFloat<px4::params::MPC_Z_VEL_MAX_DN>) _param_mpc_z_vel_max_dn,
                    (ParamFloat<px4::params::MPC_Z_VEL_MAX_UP>) _param_mpc_z_vel_max_up,
                    (ParamFloat<px4::params::MPC_TILTMAX_AIR>) _param_mpc_tiltmax_air
                       )
};