HM-4640: Dummy Positioner

In this step, you will load the LS-DYNA profile in HyperMesh.

1. Start HyperMesh Desktop.
2. In the User Profile dialog, set the user profile to LsDyna.
3. Set the template drop-down to Keyword971_R8.0.

In this step, you will open the model file and view it in HyperMesh.

1. Open a model file by completing one of the following options:
   • Click File > Open > Model from the menu bar.
   • Click on the Standard toolbar.
2. In the Open Model dialog, open the dummy_positioner.hm file.

The model appears in the graphics area.

Figure 1.

In this step, you will move the dummy to its H-Point Location on the seat.

1. From the menu bar, click Tools > Dummy to open the Dummy Browser.
2. In the Dummy Browser, click on the THOR_FE dummy entity to activate the global positioning parameters in the Entity Editor.

   
   
   Figure 2.

3. In the Entity Editor, for the Global rotation attribute Rx, enter 180.
   The dummy rotates.
4. Under H-Point location, click on the coordinates area and then click .
5. In the graphics area, select the node tagged as H-Point Location as seen in Figure 3.

   
   
   Figure 3.

6. In the panel area, click proceed.
   The dummy automatically moves to the selected H-Point location.

   
   
   Figure 4.

In this step, you will manually position the lower_leg_left and lower_leg_right body entities.

1. In the Dummy Browser, click the lower_leg_left body entity.

   
   
   Figure 5.

   The joint manipulator appears in the graphic area, and the Entity Editor opens.

   
   
   Figure 6.

2. Position the lower leg by completing one of the following:
   • In the graphics area, select the smallest blue arc on the manipulator to interactively position the lower leg to an angle value of -70°.
   • In the Entity Editor, Current angle field, enter -70.
3. In the Dummy Browser, click the lower_leg_right body entity.
4. Repeat step 2.

In this step, you will position the hands automatically .

1. In the Dummy Browser, right-click on the THOR_FE dummy entity and select Move Limbs from the context menu.
2. In the Entity Editor, set Multiple pairs to Yes.
3. Click the Select pairs field.
4. Position the left hand.
   1. In the Select multi nodes dialog, Source Point column, click on the first cell.
   2. Click the Nodes selector.
   3. In the panel area, click the node selector and enter 420848 in the id= field.
   4. Click proceed.
   5. In the Select multi nodes dialog, Target Point field, click the first cell.
   6. Click .
   7. In the graphics area, select the node tagged as Left Hand Target as seen in Figure 7.

      
      
      Figure 7.

   8. In the panel area, click proceed.
5. Position the right hand.
   1. In the Select multi nodes dialog, click to add a second row to define the Source Point and Target Point for the right hand.
   2. In the Select multi nodes dialog, Source Point column, click on the second cell.
   3. Click the Nodes selector.
   4. In the panel area, click the node selector and enter 320848 in the id= field.
   5. Click proceed.
   6. In the Select multi nodes dialog, Target Point field, click the second cell.
   7. Click .
   8. In the graphics area, select the node tagged as Right Hand Target as seen in Figure 8.

      
      
      Figure 8.

   9. In the panel area, click proceed.
6. In the Select multi nodes dialog, click Close.
7. In the Entity Editor, click Select Bodies.

   
   
   Figure 9.

8. In the Dummy Bodies DOF dialog, enable/disable dummy bodies and body DOFs to be taken into account for the automatic positioning of the dummy limbs.
   1. Deselect the bodies upper_torso and head_neck by clearing their corresponding checkbox in the Body column.
      Tip: You can also deselect a body by right-clicking on the desired body in the graphics area. Activate a body or a DOF by left-clicking on the desired body or joint arrow in the graphics area.
   2. Click OK to close the dialog.
9. In the Entity Editor, click Move to activate automatic limbs positioning.

   
   
   Figure 10.

In this step, you will save and retrieve dummy positions.

1. In the Dummy Browser, right-click on the THOR_FE dummy entity and select Define Position > New from the context menu.
2. In the Update Position info dialog, enter Final Position in the Name field and click Close.
   The actual position of the dummy is saved and can be retrieved for future reference.
3. To retrieve the initial dummy position, in the Dummy Browser, right-click on the THOR_FE dummy entity and select Retrieve Position > Initial Position from the context menu.
   The dummy automatically moves to its initial position.
4. To retrieve the saved dummy position, in the Dummy Browser, right-click on the THOR_FE dummy entity and select Retrieve Position > Other Position.
   1. In the Positions dialog, select Final Position and click Close.

In this step, you will link the dummy to a seat mechanism.

1. Open the Mechanism Browser, from the menu bar, by clicking Tools > Mechanism.
2. In the Mechanism Browser, expand the Driver_Seat mechanism to observe the different joints and bodies defined.

   
   
   Figure 11.

3. Right-click on the Driver_Seat mechanism entity and select Link To Dummy from the context menu.
4. In the Dummies dialog select THOR_FE and click Next.
5. In the Mechanism Bodies [Master Body] dialog, select Seat_Cushion and click Next.
   This body will be the master body that will drive the motion of the dummy. In the Mechanism Bodies [Master Body] dialog, the body containing the H-Point of the dummy is automatically selected, and the Body's DOF linked with the master body are automatically setup as TX; TY; TZ, which is sufficient.
6. Click Close to finalize the linking of the dummy to the seat mechanism.
   At this point, any motion of the seat will result in an according global motion of the dummy. It is also possible to constrain some bodies of the dummy that may remain in position, such as the feet.
7. Create a constraint on the ankle_left2 body.
   1. Right-click on the Driver_seat mechanism and select Create > Constraint > Point Node from the context menu.
   2. In the Entity Editor, Body field, click <Unspecified> > Body.
   3. In the Select Body dialog, select ankle_left2 and click OK.
   4. In the Entity Editor, Point node field, click <Unspecified> > Node.
   5. In the panel area, click the node selector and enter 681450 in the id= field.
   6. Click proceed.
   7. In the Entity Editor, click the Fixed DOF field and select the first four checkboxes and the last checkbox.
      The three translations and the rotations RX and RZ of the selected body are fixed in the global coordinate system. RY is free.

      
      
      Figure 12.

8. Create a constraint on the ankle_right2 body and node id=581450 with the same fixed DOF.
   1. Repeat steps 7.a and 7.b.
   2. In the Select Body dialog, select ankle_right2 and click OK.
   3. Repeat step 7.d.
   4. In the panel area, click the node selector and enter 581450 in the id= field.
   5. Repeat steps 7.f and 7.g.
9. In the Mechanism Browser, right-click on the Fix_RailToMove_Rail joint and select Move from the context menu.
10. In the Entity Editor, Current Distance field, enter -50.0.
    Notice how the dummy moves with the seat and how the position of the legs and feet are updated because of the constraints defined on the feet.

    
    
    Figure 13.