SimpleThrusterModel.h

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/*
Simple thruster model header file
 
Author: Alex Reynolds
*/
 
#ifndef MODELS_ACTUATORS_SIMPLE_THRUSTER_MODEL_H
#define MODELS_ACTUATORS_SIMPLE_THRUSTER_MODEL_H
 
#include "core/macros.h"
#include "simulation/Model.h"
#include "core/CartesianVector.hpp"
#include "six_dof_dynamics/Body.hpp"
#include "six_dof_dynamics/Node.hpp"
#include "models/support/BiasNoiseModel.h"
#include "utils/planetdefaults.h"
 
namespace modelspace {
 
    const double ON_STATE = 1e-15;   // Mdot threshold below which thruster is considered "off"
 
    enum cmds_e {
        OFF,
        ON
    };
 
    /**
     * @brief   Simple thruster model
     * 
     * This is a simple model of a thruster which applies a thrust force according
     * to mass flow and the specific impulse of the thruster. Force is applied to 
     * a node attached to the referenced body frame. The force applied by the 
     * thruster will produce a force and moment to the body as determined by the 
     * ModelSpace dynamics.
     * 
     * Noise is applied as a gaussian noise which is updated every time the thruster
     * command toggles from off to on.
     * 
     * @author Alex Reynolds <alex.reynolds@attx.tech>
    */
    class SimpleThrusterModel : public Model {
    public:
        // Model params
        //         NAME                     TYPE                    DEFAULT VALUE
        START_PARAMS
            /** The body which will be controlled by this model. The thruster force will be applied to a
             *  node aligned to this body, and ModelSpace will translate to force and torque at the body */
            SIGNAL(control_body,            BodyD*,                 nullptr)
            /** The thruster location relative to the provided body in the body frame*/
            SIGNAL(thruster_location__body, CartesianVector3D,      CartesianVector3D({0.0, 0.0, 0.0}))
            /** The thruster pointing vector in the body frame. This vector is the PLUME DIRECTION, so
             *  the actual force applied by the thruster is in the opposite direction of this vector. */
            SIGNAL(thruster_pointing__body, CartesianVector3D,      CartesianVector3D({0.0, 0.0, 0.0}))
            /** The bias in the thruster which is applied to every firing. */
            SIGNAL(thrust_bias,             double,                 0.0)
            /** The standard deviation of thruster noise which is applied firing to firing. A new noise
             *  draw is taken every time command toggles off to on. */
            SIGNAL(thrust_noise_std,        double,                 0.0)
            /** The Earth gravity in the units system of choice for the thruster (used in Isp calculation). Default is Metric.*/
            SIGNAL(g,                       double,                 clockwerk::earth_wgs84.mean_gravity)
            /** Value to seed the internal RNG for this model. */
            SIGNAL(seed_value,              int,                    0)
        END_PARAMS
 
        // Model inputs
        //         NAME                     TYPE                    DEFAULT VALUE
        START_INPUTS
            /** The mass flow rate through the thruster at the current time. */
            SIGNAL(mdot,                    double,                 0.0)
            /** The specific impulse of the thruster at the current time. */
            SIGNAL(Isp,                     double,                 0.0)
        END_INPUTS
 
        // Model outputs
        //         NAME                     TYPE                    DEFAULT VALUE
        START_OUTPUTS
            /** The thrust applied by the thruster at its location on the spacecraft body */
            SIGNAL(applied_thrust,          double,                  0.0)
            /** The force applied by the thruster as a vector value in the body frame.
             *  This is an informational output. Force is automatically applied to the node. */
            SIGNAL(applied_force__body,     CartesianVector3D,      CartesianVector3D({0.0, 0.0, 0.0}))
        END_OUTPUTS
 
        // Model-specific implementations of startup and derivative
        SimpleThrusterModel();
        SimpleThrusterModel(Model &pnt, const std::string &m_name="simple_thruster");
        SimpleThrusterModel(SimulationExecutive &e, const std::string &m_name="simple_thruster");
        SimpleThrusterModel(Model &pnt, int schedule_slot, const std::string &m_name="simple_thruster");
        SimpleThrusterModel(SimulationExecutive &e, int schedule_slot, const std::string &m_name="simple_thruster");
        ~SimpleThrusterModel() {}
 
        // Getters for handles to respective frames
        // TODO: Fix this to not be needed because these can all be public. Until then it's here
        clockwerk::DataIO<NodeD*> thrusterNode = clockwerk::DataIO<NodeD*>(this, "thrusterNode", &_thruster_node);
    protected:
        int start();
        int execute();
 
        /// @brief The bias and noise model for thrust output.
        BiasNoiseModel _thruster_bias_noise;
 
        /// @brief The node at which thrust is applied.
        NodeD _thruster_node;
 
        /// @brief Our nominal thrust calculation from Isp and the like.
        double _nominal_thrust = 0.0;
 
        /// @brief Value to hold perturbation to thrust
        double _thrust_perturbation = 0.0;
 
        /// @brief Value to hold total thrust calculation
        double _total_thrust = 0.0;
 
        /// @brief Value to hold last thrust command
        int _cmd_state = OFF;
        int _prev_cmd = OFF;
    };
 
}
 
#endif