def test_distal_node_velocity_due_to_hinge_rotation_has_correct_axis(self): h = Hinge('hinge', [0, 0, 1]) h.vstrain[0] = 4.5 # rad/s h.calc_kinematics() assert_array_equal(h.F_vp, eye(6)) # distal node moves with prox assert_array_equal(h.F_ve[:3, 0], zeros(3)) # hinge ang vel is assert_array_equal(h.F_ve[3:, 0], [0, 0, 1]) # about axis assert_array_equal(h.F_v2, zeros(6)) # no quadratic force, base fixed