Positioning, Tree File
The WorldSID model is delivered with a tree file for the OASYS Primer pre-processor (may also work for ALTAIR Hypermesh, BETA CAE-Systems ANSA and LS-PrePost, not verified by DYNAmore). This allows the user to position the dummy and adjust the parts according to their degrees of freedom. Figure 16 shows the connections of movable parts via tree file. All revolute joints are visualized by beams.
Figure 16: Tree-file assemblies of the WorldSID model
Two coordinate systems are modelled at the H-Point of the dummy model. These coordinate systems are connected to each other by a spherical joint. One coordinate system is constrained to global directions, which means only translations are possible, rotations are disabled. The other one is connected to the dummy, thus making it possible to measure the pelvis angle of the WorldSID during the positioning simulation quickly and easily. These coordinate systems are also used to determine the initial pelvis angle with OASYS-Primer.
Movable parts and revolute joints are:
| Assembly | Stop Angles |
|---|---|
| Foot, left and right about their ankle joints Local x-axis Local y-axis Local z-axis |
Stop angle: -21.0 and 21.0 degrees Stop angle: -48.0 and 48.0 degrees Stop angle: -29.0 and 29.0 degrees |
| Lower leg, left and right about their knee joints: Local y-axis |
Stop angle: -0.1 and 145.0 degrees |
| Upper leg bone, left and right about hip joint Local x-axis Local y-axis Local z-axis |
Stop angle: -1.0 and 1.0 degrees Stop angle: -2.5 and 2.0 degrees Stop angle: -2.0 and 2.0 degrees
|
The stop angles of the feet and the knees are adjusted to the physical range of motion of the individual components. But for the hip joint, there is no physical blocking in the WorldSID. However it might be possible that some pre-processors do not support the stop function of this tree-file structure. In this case, initial penetrations can occur if the upper legs are rotated at the hip joints beyond the values given in the table above. This reaction is based on the hardware. In the hardware, the geometry is deformed if the position of the upper leg is changed with respect to the pelvis.
The arms cannot be rotated in a pre-processor, because the jacket has to be deformed when the arms rotate. Here we recommend a pre-simulation to rotate the arm in the desired position.
