Forklift Contact Forces and STEP Function Tutorial

1. Forklift Estimated time required: 20 min GUI familiarity level required: Higher MSC.ADAMS 2005 r2

2. Topics Covered In this tutorial, you will learn how to: • Create a STEP function • Create contact You will need to download the file “FORKLIFT_model_start.zip“ to begin this tutorial If you have any difficulties, import the “FORKLIFT_shortcut.cmd” file and proceed from pg 10 If you have any difficulties, import the “FORKLIFT_complete.cmd” file and proceed from pg 13

3. Forklift Problem Add contact forces and STEP function to delay movements of a forklift.

4. What You Should Accomplish If you are successful, you should end up with a ADAMS model that illustrates contact forces and STEP function of a forklift.

5. Import Model • Download file FORKLIFT_model_start.zip • Unzip the files to C:\ • Start ADAMS • Click Import a file radio button • Select C:\ as Start in text field • Click OK d e f • File Import window will open • Right-click File To Read text field, select Browse • Locate saved file FORKLIFT_start.cmd • Click Open • Click OK h g i j

6. Add Translation Joint • Select Translation Joint from Joint tool stack • Click ground  PAR2  PAR2.MAR1  move cursor to the right, click MAR1.Z • Select Translation Joint • Click PAR2  PAR3  PAR2.lift2_22.V229  move cursor up, click lift2_22.V6 a d b

7. Add Translation Joint Motion • Select Translational joint motion from Motion Driver tool stack • Click JOINT_1 • Select Translational joint motion • Click JOINT_2 a d b

8. Create STEP funtion • Right Click on JOINT_1, select Motion:MOTION_1  Modify • Click button • Enter STEP(time, 2.0, 0.0, 6.0, 150) in Define a runtime function text field • Click OK • Click OK c b a e d Note: the step function is a delayed movement function. It works like: STEP(time, time, distance, time 2, distance 2)

9. Create STEP function • Right Click on JOINT_2, select Motion_1  Modify • Click button • Enter STEP(time, 0.5, 0.0, 4.0, +36) + STEP5(time, 6.0, 0.0, 8.5, -36) • Click OK • Click OK

10. Create Contact • Select Contact from Forces tool stack • Right-click in I Solid text field, select Contact_Solid  Browse • Highlight BOX_42, BOX_43, BOX_44  Click OK • Repeat for J Solid except use PAR3  EXTRUSION_45, EXTRUSION_46 • Choose Blue from Force Display pull down menu • Enter Stiffnees = (Stiff_Box_Fork) , Force Exponent = (Exp_box_fork) , Damping = (B_box_fork) , Penetration Depth = (Dmax_box_fork) • Choose Coulomb from Friction Force pull down menu • Enter Static Coefficient = 0.3, Dynamic Coefficient = 0.2, Striction Transition = 10.0, Friction Transition = 100.0 • Click OK b c d e a f g h i

11. Create Contact • I Solid= PAR3  BOX_42, BOX_43, BOX_44 • J Solid =ground  BOX_21 • Choose Blue from Force Display pull down menu • Enter: • Stiffness =(Stiff_Box_Ground) • Force Exponent =(Exp_box_ground) • Damping =(B_box_ground) • Penetration Depth = (Dmax_box_ground) • Choose Coulomb from Friction Force pull down menu • Enter: • Static Coefficient = 0.62 • Dynamic Coefficient = 0.6 • Striction Transition = 10.0 • Friction Transition = 100.0 • Click OK a b c d e f g

12. Model This is what your screen should look like when your model is complete

13. Verify Verify the model Run a Simulation: Duration = 10, Step Size = 0.1

14. Topics Covered In this tutorial you learned how to: • Create a STEP function • Create contact

15. Best Practices • Check orientation and location of the translation joint • Check direction of translation joint motion • Check STEP function • Check Contact forces are between the right bodies • Check Contact values