finishing touches

src/components.jl

@@ -306,16 +306,16 @@ Representing a body with 3 translational and 3 rotational degrees-of-freedom.
  @variables phid(t)[1:3]=phid0 [state_priority = 10]
  @variables phidd(t)[1:3]=zeros(3) [state_priority = 10]
  phi, phid, phidd = collect.((phi, phid, phidd))
- ar = axes_rotations([1, 2, 3], phi, phid)
+ ar = axes_rotations([1, 2, 3], phi, -phid) # NOTE: this - sign is mysterious, it was not required before the change to axis_rotation in https://github.com/JuliaComputing/Multibody.jl/pull/93, but the change in the PR was checked by comparing Multibody.RotX(pi/2) and angle = pi/2; [1 0 0; 0 cos(angle) sin(angle); 0 -sin(angle) cos(angle)] which is the modelica implementation of RotX. It appears related to vef_from_R, if the - is removed, vel_from_R can be set to false in swing example. 
  Equation[
  phid .~ D.(phi)
  phidd .~ D.(phid)
  Ra ~ ar
- Ra.w .~ w_a
+ Ra.w .~ ar.w
  if vel_from_R
  w_a .~ angular_velocity2(ori(frame_a, false)) # This is required for FreeBody and ThreeSprings tests to pass, but the other one required for harmonic osciallator without joint to pass. FreeBody passes with quat=true so we use that instead
  else
- w_a .~ ar.w # This one for most systems
+ w_a .~ angular_velocity2(ar) # This one for most systems
  end
  ]
  end

test/runtests.jl

@@ -663,7 +663,7 @@ using LinearAlgebra
 # @testset "Rolling wheel" begin
 @mtkmodel WheelInWorld begin
  @components begin
- world = World(render=true)
+ world = W()
  wheel = RollingWheel(radius = 0.3, m = 2, I_axis = 0.06,
  I_long = 0.12,
  x0 = 0.2,
@@ -675,6 +675,7 @@ end
 @named worldwheel = WheelInWorld()
 worldwheel = complete(worldwheel)
 
+# pars = collect(worldwheel.world.n) .=> [0,0,-1];
 defs = Dict([
  collect(worldwheel.world.n) .=> [0,0,-1];
  worldwheel.wheel.body.r_0[1] => 0.2;