TriadGuidance.h

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/*
Triad method guidance task header file
 
Author: Alex Jackson
*/
 
#ifndef TRIAD_GUIDANCE_H
#define TRIAD_GUIDANCE_H
 
#include "core/macros.h"
#include "architecture/Tasks.h"
#include "six_dof_dynamics/Frame.hpp"
#include "six_dof_dynamics/MRP.hpp"
 
namespace clockwerk {
 
    /**
     * @brief   Triad method guidance
     * 
     * This task applies a simple pointing guidance based on the Triad method
     * for attitude determination. In this approach, two body axes are selected,
     * along with desired vectors in the reference frame to which they should
     * point. The task calculates the attitude body/reference which fully meets
     * the primary pointing constraint and attempts a best effort at the secondary
     * pointing constraint.
    */
    class TriadGuidance : public Task {
    public:
        // Model params
        //         NAME                     TYPE                    DEFAULT VALUE
        START_PARAMS
 
        END_PARAMS
 
        // Model inputs
        //         NAME                     TYPE                    DEFAULT VALUE
        START_INPUTS
            /** The body axis vector which will be pointed to desired_primary */
            SIGNAL(current_primary_body,     CartesianVector3D,       CartesianVector3D({1.0, 0.0, 0.0}))
            /** The desired primary vector expressed in an arbitrary frame */
            SIGNAL(desired_primary,          CartesianVector3D,        CartesianVector3D({1.0, 0.0, 0}))
            /** The body axis vector which will be pointed to desired_secondary */
            SIGNAL(current_secondary_body,    CartesianVector3D,      CartesianVector3D({0.0, 1.0, 0.0}))
            /** The desired secondary vector expressed in an arbitrary frame */
            SIGNAL(desired_secondary,        CartesianVector3D,       CartesianVector3D({0.0, 1.0, 0.0}))
        END_INPUTS
 
        // Model outputs
        //         NAME                     TYPE                    DEFAULT VALUE
        START_OUTPUTS
            /** The desired attitude of the s/c body with respect to a reference frame that the desired primary and secondary were expressed in */
            SIGNAL(quat_body_ref,           Quaternion<double>,     Quaternion<double>({0.0, 0.0, 0.0}))
        END_OUTPUTS
 
 
        // Model-specific implementations of startup and derivative
        TriadGuidance() : Task() {}
        TriadGuidance(Task &pnt, int schedule_slot=0, const std::string &m_name="triad_guidance")
            : Task(pnt, schedule_slot, m_name) {}
        TriadGuidance(Executive &e, int schedule_slot=0, const std::string &m_name="triad_guidance")
            : Task(e, schedule_slot, m_name) {}
        ~TriadGuidance() {}
    protected:
        int execute();
 
        // Local vectors to establish DCM -- here for speed
        CartesianVector3D _body_triadx;
        CartesianVector3D _body_triady;
        CartesianVector3D _body_triadz;
        CartesianVector3D _ref_triadx;
        CartesianVector3D _ref_triady;
        CartesianVector3D _ref_triadz;
 
        // Local variables for DCM body/ref to MRP conversion
        DCMD _dcm_body_ref;
        QuaternionD _quat_body_ref;
    };
 
}
 
#endif