1. WORKSHOP 18
HATCHBACK II

3. Workshop Objectives Software Version Files Required
Find the approximate maximum force at the winglet required to close the lid in three seconds for the given Mazda MX-6 hatchback model
Software Version
Adams 2013
Files Required
Use file hatchback.cmd
Located in the directory exercise_dir/mod_17_hatchback_1
Problem Description
In this workshop, you will use the model you built in Workshop 17 - Hatchback I.

4. Model Overview:

5. Suggested Steps Import model. Measure the rotation of the Lid.
Close the Lid.
Create a simulation script.
Perform a simulated script.
Create a torque measure.
Deactivate the measure.
Inspect the torque measure.
Save your work.

6. Step 1. Import Model To import model:
Start Adams/View from the directory exercise_dir/mod_18_hatchback_2.
From the directory exercise_dir/mod_17_hatchback_1, import the model that you created in the previous module.
If you need a copy of the completed model you can import the command file named hatchback_1_completed.cmd which is found in the directory exercise_dir/mod_17_hatchback_1/completed.

7. Step 2. Measure the Rotation of the Lid
To measure the rotation of the lid:
Right-click l_shortarm_rev joint and create a measure, named shortarm_rotation, of the rotational displacement:
Characteristic: Ax/Ay/Az Projected Rotation
Component: Z
From/At: .ground.MAR_7
Run a 5-second, 50-step simulation.
In Adams/PostProcessor, plot the shortarm_rotation versus time.
From the shortarm_rotation plot, use the Plot Tracking tool to determine the steady-state angle of the left_shortarm.
The steady-state angle is d. a a b d d c

8. Step 3. Close the Lid
Currently the lid opens because of the preload in the springs and stops opening because of the impact forces.
To close the lid, you will rotate the left_shortarm part back to its original position as shown next. To rotate the left_shortarm, apply a joint motion to the left_shortarm_rev joint as explained next.

9. Step 3. Close the Lid (Cont.)a
To create a motion to close the lid:
Create a joint motion on the joint l_shortarm_rev, named closing_motion.
Use a STEP function to modify the motion to drive the lid back to its closed position:
Start the STEP function at the steady-state rotation (determined later in the workshop) of the left_shortarm at 4 seconds.
End the STEP function at 0º rotation of the left_shortarm at 7 seconds.
The function should look as shown next: STEP(time, 4.0, d, 7.0, 0.0d) b a

10. Step 4. Create a Simulation Script
In this section, you’ll create a simulation script containing Adams/Solver commands that deactivate the motion and run a simulation, then activate the motion and run a second simulation.
To create the script:
From the ribbon Simulation, select an icon Create a New Simulation Script.
Name the script, script_1.
Set Script Type to Adams/Solver Commands.
Enter the following Adams/Solver commands:
DEACTIVATE/MOTION, id=1
SIMULATE/DYNAMIC, END=4, STEPS=40
ACTIVATE/MOTION, id=1
SIMULATE/KINEMATIC, END=7, STEPS=30
Select OK. b c d e

11. Step 5. Perform a Scripted Simulation
To perform a scripted simulation:
From the ribbon Simulation, select Run a Scripted Simulation.
Enter the name of the script that you created, script_1.
Select the Play tool. c b a

12. Step 6. Create a Torque Measure
Measure the torque:
You now create a measure of the torque required to close the lid. You then deactivate this measure because it is dependent on the motion that is deactivated when the scripted simulation starts.
To create the measure:
Create a motion measure, named closing_torque_measure (right-click closing_motion, and then select Measure):
Characteristic: Torque
Component: Z a a

13. Step 7. Deactivate the Measure
To deactivate the measure:
By default, when you deactivate something using the Edit menu, Adams/View deactivates anything that is currently in your Select list. Therefore, first clear your Select list by selecting the Select tool, so you do not accidentally deactivate something else in your model.
From the Edit menu, select Deactivate.
Use the Browse option to filter only on measures.
Select closing_torque_measure.
Select OK. b a

14. Step 8. Inspect the Torque Measure
To inspect the torque measure:
In Adams/PostProcessor, plot torque in the motion versus time (the closing_torque_measure).
The figure represents the approximate amount of torque required to close the lid. a b

15. Step 8. Inspect the Torque Measure (Cont.)
Edit the torque curve to find the approximate force required to lower the lid in three seconds. To find this force, use the Scale a Curve tool to divide the motion torque by a moment arm of 700 mm:
To display the Scale a Curve tool, from the View menu (inside Adams/PostProcessor), point to Toolbars, and then select Curve Edit Toolbars.
A new toolbar appears.
Select the Scale a Curve tool.
Set Scale to 1/700.
Select the curve on the graph. a d b c

16. Step 8. Inspect the Torque Measure (Cont.)
To display only the force curve, delete the motion torque curve.
The figure represents the approximate amount of force required to close the lid.
Note the approximate maximum force required to close the lid. Use the value to answer Question 1 in Module review.

17. Save your work
To save your work:
Save your model.
Exit Adams/View.

18. Workshop 18, Review
What is the approximate maximum force required to close the lid? ______________________________________________________________________________________________________________
Is it possible to modify a force from one constant value to another instantaneously, such as shutting off a motor’s torque? ______________________________________________________________________________________________________________
Is it possible to use different output step sizes over different intervals by submitting an interactive simulation? ______________________________________________________________________________________________________________