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Merged
merged 2 commits into from
Nov 23, 2020
Merged

Get minimal velocity #38

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7881fe5
Fix example
janbruedigam Nov 22, 2020
78c40cc
Add get minimal velocity function
janbruedigam Nov 22, 2020
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3 changes: 1 addition & 2 deletions examples/doublependulum_3d.jl
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Expand Up @@ -23,11 +23,10 @@ q1 = UnitQuaternion(RotX(phi1))
# Links
origin = Origin{Float64}()
link1 = Body(b1)
socket0to1 = EqualityConstraint(Spherical(origin, link1; p2=vert11))
link2 = Body(b2)

# Constraints

socket0to1 = EqualityConstraint(Spherical(origin, link1; p2=vert11))
socket1to2 = EqualityConstraint(Spherical(link1, link2; p1=vert12, p2=vert21))

links = [link1;link2]
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9 changes: 9 additions & 0 deletions src/joints/rotational.jl
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Expand Up @@ -256,3 +256,12 @@ end
q = stateb.qc / joint.qoffset
return nullspacemat(joint) * rotation_vector(q)
end
@inline function minimalVelocities(joint::Rotational, body1::Body, body2::Body)
statea = body1.state
stateb = body2.state
return nullspacemat(joint) * (vrotate(stateb.ωc,statea.qc\stateb.qc) - statea.ωc) # in body1's frame
end
@inline function minimalVelocities(joint::Rotational, body1::Origin, body2::Body)
stateb = body2.state
return nullspacemat(joint) * vrotate(stateb.ωc,stateb.qc) # in body1's frame
end
9 changes: 9 additions & 0 deletions src/joints/translational.jl
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Expand Up @@ -255,3 +255,12 @@ end
stateb = body2.state
return nullspacemat(joint) * g(joint, stateb.xc, stateb.qc)
end
@inline function minimalVelocities(joint::Translational, body1::Body, body2::Body)
statea = body1.state
stateb = body2.state
return nullspacemat(joint) * (stateb.vc - statea.vc)
end
@inline function minimalVelocities(joint::Translational, body1::Origin, body2::Body)
stateb = body2.state
return nullspacemat(joint) * stateb.vc
end
5 changes: 5 additions & 0 deletions src/main_components/equalityconstraint.jl
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Expand Up @@ -118,6 +118,11 @@ end
return :(svcat($(vec...)))
end

@generated function minimalVelocities(mechanism, eqc::EqualityConstraint{T,N,Nc}) where {T,N,Nc}
vec = [:(minimalVelocities(eqc.constraints[$i], getbody(mechanism, eqc.parentid), getbody(mechanism, eqc.childids[$i]))) for i = 1:Nc]
return :(svcat($(vec...)))
end

@inline function GtλTof!(mechanism, body::Body, eqc::EqualityConstraint)
isactive(eqc) && (body.state.d -= zerodimstaticadjoint(∂g∂ʳpos(mechanism, eqc, body.id)) * eqc.λsol[2])
return
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