Source code for RCAIDE.Library.Mission.Common.Update.stability

# RCAIDE/Library/Missions/Common/Update/stability.py
# 
# 
# Created:  Jul 2023, M. Clarke 

import numpy as np
import RCAIDE
# ----------------------------------------------------------------------------------------------------------------------
#  Stability
# ---------------------------------------------------------------------------------------------------------------------- 


def stability(segment): 
    """ Updates the stability of the aircraft 
        
        Assumptions:
        If stability model is defined, overwrite the aerodynamics calculations
        
        Inputs:
            None 
                 
        Outputs: 
            None
      
        Properties Used:
        N/A
                    
    """   
    # unpack
    stability_model    = segment.analyses.stability
    conditions         = segment.state.conditions
     
    if stability_model != None:
        
        # check to see if results have already been calculated using the Aero analyses
        if ((type(segment.analyses.stability) == RCAIDE.Framework.Analyses.Stability.Vortex_Lattice_Method) and (type(segment.analyses.aerodynamics) == RCAIDE.Framework.Analyses.Aerodynamics.Vortex_Lattice_Method)) or \
            ((type(segment.analyses.stability) == RCAIDE.Framework.Analyses.Stability.Athena_Vortex_Lattice) and (type(segment.analyses.aerodynamics) == RCAIDE.Framework.Analyses.Aerodynamics.Athena_Vortex_Lattice)):
            pass
        else:
            Sref               = stability_model.vehicle.reference_area
            MAC                = stability_model.vehicle.wings.main_wing.chords.mean_aerodynamic
            span               = stability_model.vehicle.wings.main_wing.spans.projected
            q                  = segment.state.conditions.freestream.dynamic_pressure
            CLmax              = stability_model.settings.maximum_lift_coefficient
    
            _ = stability_model(segment)
     
            # Forces 
            CL = conditions.aerodynamics.coefficients.lift.total
            CD = conditions.aerodynamics.coefficients.drag.total
            CY = conditions.static_stability.coefficients.Y
    
            CL[q<=0.0] = 0.0
            CD[q<=0.0] = 0.0
            CL[CL>CLmax] = CLmax
            CL[CL< -CLmax] = -CLmax
    
            # dimensionalize
            F      = segment.state.ones_row(3) * 0.0
            F[:,2] = ( -CL * q * Sref )[:,0]
            F[:,1] = ( -CY * q * Sref )[:,0]
            F[:,0] = ( -CD * q * Sref )[:,0]
    
            # rewrite aerodynamic CL and CD
            conditions.aerodynamics.coefficients.lift.total  = CL
            conditions.aerodynamics.coefficients.drag.total  = CD
            conditions.frames.wind.force_vector[:,:]   = F[:,:]
    
            # -----------------------------------------------------------------
            # Moments
            # -----------------------------------------------------------------
            CM = conditions.static_stability.coefficients.M
            CL = conditions.static_stability.coefficients.L
            CN = conditions.static_stability.coefficients.N
    
            CM[q<=0.0] = 0.0
    
            # dimensionalize
            M      = segment.state.ones_row(3) * 0.0
            M[:,0] = (CL[:,0] * q[:,0] * Sref * span)
            M[:,1] = (CM[:,0] * q[:,0] * Sref * MAC)
            M[:,2] = (CN[:,0] * q[:,0] * Sref * span)
    
            # pack conditions
            conditions.frames.wind.moment_vector[:,:] = M[:,:]

    return