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✨ Add Euler angles => CRP and MRP conversions
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Lines changed: 135 additions & 2 deletions

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‎src/ReferenceFrameRotations.jl‎

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@@ -60,7 +60,9 @@ include("deprecations.jl")
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include("./conversions/angle_to_angle.jl")
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include("./conversions/angle_to_angleaxis.jl")
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include("./conversions/angle_to_crp.jl")
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include("./conversions/angle_to_dcm.jl")
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include("./conversions/angle_to_mrp.jl")
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include("./conversions/angle_to_quat.jl")
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include("./conversions/angle_to_rot.jl")
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include("./conversions/angleaxis_to_angle.jl")

‎src/conversions/angle_to_crp.jl‎

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## Description #############################################################################
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#
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# Functions related to the conversion from Euler angles to CRP.
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#
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############################################################################################
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export angle_to_crp
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"""
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angle_to_crp(θ₁::Number, θ₂::Number, θ₃::Number, rot_seq::Symbol = :ZYX) -> CRP
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angle_to_crp(Θ::EulerAngles) -> CRP
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Convert the Euler angles `θ₁`, `θ₂`, and `θ₃` [rad] with the rotation sequence `rot_seq` to
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classical Rodrigues parameters.
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Those values can also be passed inside the structure `Θ` (see [`EulerAngles`](@ref)).
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The rotation sequence is defined by a `:Symbol`. The possible values are: `:XYX`, `XYZ`,
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`:XZX`, `:XZY`, `:YXY`, `:YXZ`, `:YZX`, `:YZY`, `:ZXY`, `:ZXZ`, `:ZYX`, and `:ZYZ`. If no
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value is specified, it defaults to `:ZYX`.
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"""
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@inline function angle_to_crp(
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θ₁::Number,
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θ₂::Number,
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θ₃::Number,
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rot_seq::Symbol = :ZYX
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)
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return dcm_to_crp(angle_to_dcm(θ₁, θ₂, θ₃, rot_seq))
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end
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@inline angle_to_crp(Θ::EulerAngles) = angle_to_crp(Θ.a1, Θ.a2, Θ.a3, Θ.rot_seq)

‎src/conversions/angle_to_mrp.jl‎

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## Description #############################################################################
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#
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# Functions related to the conversion from Euler angles to MRP.
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#
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############################################################################################
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export angle_to_mrp
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"""
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angle_to_mrp(θ₁::Number, θ₂::Number, θ₃::Number, rot_seq::Symbol = :ZYX) -> MRP
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angle_to_mrp(Θ::EulerAngles) -> MRP
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Convert the Euler angles `θ₁`, `θ₂`, and `θ₃` [rad] with the rotation sequence `rot_seq` to
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modified Rodrigues parameters.
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Those values can also be passed inside the structure `Θ` (see [`EulerAngles`](@ref)).
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The rotation sequence is defined by a `:Symbol`. The possible values are: `:XYX`, `XYZ`,
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`:XZX`, `:XZY`, `:YXY`, `:YXZ`, `:YZX`, `:YZY`, `:ZXY`, `:ZXZ`, `:ZYX`, and `:ZYZ`. If no
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value is specified, it defaults to `:ZYX`.
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"""
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@inline function angle_to_mrp(
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θ₁::Number,
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θ₂::Number,
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θ₃::Number,
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rot_seq::Symbol = :ZYX
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)
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return dcm_to_mrp(angle_to_dcm(θ₁, θ₂, θ₃, rot_seq))
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end
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@inline angle_to_mrp(Θ::EulerAngles) = angle_to_mrp(Θ.a1, Θ.a2, Θ.a3, Θ.rot_seq)

‎src/conversions/api.jl‎

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@@ -64,14 +64,14 @@ Base.convert(::Type{<:Quaternion}, a::MRP) = mrp_to_quat(a)
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Base.convert(::Type{<:CRP}, a::DCM) = dcm_to_crp(a)
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Base.convert(::Type{<:CRP}, a::Quaternion) = quat_to_crp(a)
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Base.convert(::Type{<:CRP}, a::EulerAngles) = dcm_to_crp(angle_to_dcm(a))
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Base.convert(::Type{<:CRP}, a::EulerAngles) = angle_to_crp(a)
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Base.convert(::Type{<:CRP}, a::EulerAngleAxis) = dcm_to_crp(angleaxis_to_dcm(a))
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Base.convert(::Type{<:CRP}, a::MRP) = dcm_to_crp(mrp_to_dcm(a))
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# == Conversions to MRP ====================================================================
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Base.convert(::Type{<:MRP}, a::DCM) = dcm_to_mrp(a)
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Base.convert(::Type{<:MRP}, a::Quaternion) = quat_to_mrp(a)
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Base.convert(::Type{<:MRP}, a::EulerAngles) = dcm_to_mrp(angle_to_dcm(a))
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Base.convert(::Type{<:MRP}, a::EulerAngles) = angle_to_mrp(a)
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Base.convert(::Type{<:MRP}, a::EulerAngleAxis) = dcm_to_mrp(angleaxis_to_dcm(a))
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Base.convert(::Type{<:MRP}, a::CRP) = dcm_to_mrp(crp_to_dcm(a))

‎test/conversions/angle_to_crp.jl‎

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## Desription ##############################################################################
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#
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# Tests related to conversion from Euler angles to CRP.
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#
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############################################################################################
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# == File: ./src/conversions/angle_to_crp.jl ===============================================
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# -- Functions: angle_to_crp ---------------------------------------------------------------
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@testset "Euler angles => CRP" begin
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for T in (Float32, Float64)
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# We do not need comprehensive tests here because `angle_to_crp` first converts the
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# Euler angles to DCM and then to CRP. Those two operations are already heavily
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# tested.
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testset = [
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EulerAngles(T( 0.2), T(-0.1), T( 0.3), :ZYX)
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EulerAngles(T( 0.5), T( 0.4), T(-0.2), :XYZ)
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EulerAngles(T(-0.3), T( 0.2), T( 0.6), :ZXZ)
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]
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for ea in testset
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c = angle_to_crp(ea)
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@test c isa CRP{T}
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@test c ≈ dcm_to_crp(angle_to_dcm(ea))
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c2 = angle_to_crp(ea.a1, ea.a2, ea.a3, ea.rot_seq)
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@test c2 ≈ c
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end
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end
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end
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@testset "Euler angles => CRP (Singularity)" begin
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@test_throws ArgumentError angle_to_crp(π, 0.0, 0.0, :XYZ)
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@test_throws ArgumentError angle_to_crp(EulerAngles(π, 0.0, 0.0, :XYZ))
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end

‎test/conversions/angle_to_mrp.jl‎

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## Desription ##############################################################################
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#
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# Tests related to conversion from Euler angles to MRP.
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#
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############################################################################################
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# == File: ./src/conversions/angle_to_mrp.jl ===============================================
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# -- Functions: angle_to_mrp --------------------------------------------------------------
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@testset "Euler angles => MRP" begin
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for T in (Float32, Float64)
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# We do not need comprehensive tests here because `angle_to_mrp` first converts the
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# Euler angles to DCM and then to MRP. Those two operations are already heavily
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# tested.
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testset = [
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EulerAngles(T( 0.2), T(-0.1), T( 0.3), :ZYX)
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EulerAngles(T( 0.5), T( 0.4), T(-0.2), :XYZ)
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EulerAngles(T(-0.3), T( 0.2), T( 0.6), :ZXZ)
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]
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for ea in testset
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m = angle_to_mrp(ea)
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@test m isa MRP{T}
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@test m ≈ dcm_to_mrp(angle_to_dcm(ea))
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m2 = angle_to_mrp(ea.a1, ea.a2, ea.a3, ea.rot_seq)
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@test m2 ≈ m
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end
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end
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end

‎test/runtests.jl‎

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@time @testset "Conversions" verbose = true begin
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include("./conversions/angle_to_angle.jl")
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include("./conversions/angle_to_angleaxis.jl")
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include("./conversions/angle_to_crp.jl")
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include("./conversions/angle_to_dcm.jl")
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include("./conversions/angle_to_mrp.jl")
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include("./conversions/angle_to_quat.jl")
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include("./conversions/angle_to_rot.jl")
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include("./conversions/angleaxis_to_angle.jl")

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