WORKSHOP 1 introduction

Software Version Files Required Problem statement Adams 2012 build.cmd (plus other files referenced within the mod_01_intro directory) Problem statement In this workshop you will use a custom interface to solve a given problem, which levers a parameterized model. You need to determine the locations of joints in a mechanism so that a disk can be dropped at a desired angle. The customized graphical user interface (GUI) can be used in several ways: Move joint locations Simulate Animate Calculate a value of interest Optimize Perform tolerance check After using the interface provided, you will appreciate the advantages of a parameterized model with customized interface.

Model information This model represents a disk transfer mechanism: Disks are stacked in a bin and must be moved to a table. A series of links are constructed and driven by a pulley. The joint locations for each link must be determined so that the disk is oriented at a prescribed drop angle midway through its duty cycle. Throughout the cycle, it should neither strike the bin nor clash with the table.

Getting Started To get started: Start ADAMS/View. Select Existing Model and import the command file build.cmd from the exercise_dir/mod_01_intro directory. Be sure to use the default options, such as Use File Directory as Working Directory = Yes. This will import the disk transfer model and the interface customizations. From the View menu, select Revolve Model (custom menu button). Familiarize yourself with the model as it revolves about the y-axis of the view window. Run a 1-second / 50-step simulation to see how it operates. Reset the model and select a front view.

Changing the Design In this section you will see how to change key locations of your mechanism. To change the model: From the Disk menu, select Design Layout. In the Design Layout dialog box, select the design point you want to modify. Observe the current x and y coordinates in the text boxes. Use the + or - button to change the point location. Because the model is parameterized, all model dependencies update when you change these locations. Watch the model change as you press these buttons. Reset your model to the original design by selecting Reset All. Leave the Design Layout dialog box open and continue with the next step. Note: The buttons use increments of 2 mm per click. Note: If you move the points too far, you will encounter a hardcoded out-of-range error.

Simulating the Model Now you'll simulate the model to see how it behaves. To simulate the model: From the Disk Transfer menu, select Simulate. To simulate the current design configuration, make sure that Single is selected. Select Apply. Leave the Simulate dialog box open and continue with the next step. Tip: If you change the Model Display option menu from At Every Output Step to Never, the model solves faster, but does not update on the screen.

Reviewing the Results Now you'll look at results of the simulation as an animation and a calculated value of interest. To review results: From the Disk Transfer menu, select Review Results. Select Animate to see the motion from your last simulation. It will also draw some animation traces of markers at the corners of the disk. Select Reset in the Review dialog box when you're done animating. Tip: If necessary, use the Stop button in the lower right corner of the screen to stop an animation before it has completed.

Determining the Drop Angle To automatically find the drop angle: Select Actual Angle in the Review dialog box to determine the drop angle of the last simulated design. What is the drop angle for the baseline design? When you’re done, close the Information window. Leave the Review dialog box open and continue with the next step.

Determining the Drop Angle To manually find the drop angle: Adjust the locations of points 1, 2, and/or 4 so that the resulting drop angle is approximately -2 degrees (relative to the table). Did you succeed at finding a drop angle of -2 degrees in three tries or less? Yes, my angle was No, it was too difficult. Note: Visually verify that the disk does not clash with the table throughout its cycle.

Finding the Drop Angle using Optimization Now, you’ll perform an optimization study. During the optimization, ADAMS/View systematically varies the point locations and runs a number of simulations until the desired drop angle is achieved. To perform an optimization study: Reset the point locations by selecting Reset All in the Design Layout dialog box. In the Simulate dialog box, select Optimize and enter a Desired Drop Angle of -2 degrees. Select Apply to perform the optimization study. As the optimization runs, you may notice that the status bar updates with the iterations and passes used by the optimization algorithm. Please be patient, as this will take a few minutes. Note: We highly recommend that you set the Model Display option to At Simulation End to greatly speed up the individual simulations.

Finding the Drop Angle using Optimization A strip chart will be displayed, indicating the progress the optimizer is making by plotting the objective versus iteration. Once the optimization study is completed, an optimization summary will be displayed in the Information window. Which design variable coordinate had the largest percentage change from its initial value? Which design variable coordinate had the smallest percentage change from its initial value? What are the optimized variable values? X Y Point 1 Point 2 Point 3

Finding the Drop Angle using Optimization Close the Information window. As a confirmation, perform a single simulation using the design configuration that the optimizer found. Compare the desired drop angle to the actual drop angle. Was the optimization study successful? Yes No

Performing a Tolerance Check Next, you will see the effect of manufacturing tolerance on the drop angle. The optimized configuration will be considered the nominal value. To perform a tolerance check: In the Simulate dialog box, select Tolerance Check. Using a tolerance of 1 mm, perform a tolerance check for the variables that had the largest and smallest percent change from the optimization report (see steps 3 and 4 in the previous section). Write down the value of the objective for each trial: -1 mm (degrees) Nominal +1 mm (degrees) Point 4x (DV_p4_x) Point 2x (DV_p2_x)

Workshop Wrap-up This workshop used the following capabilities of ADAMS/View: A fully parameterized model Design studies Optimization studies Custom menus Custom macros Custom dialog boxes Throughout this course, the first three concepts and features above (parameterization, design studies, and optimization studies) will be taught in detail. At the end of this course, you will be able to apply these concepts with your own virtual prototypes.

Optional Tasks The following task can be optionally performed, time permitting: Allow the disk to be dropped to the table during the simulation. Run a scripted simulation (by selecting the Simulation tab, then Run a Scripted Simulation icon ), using .model_1.DROP_DISK_SCRIPT in the Simulation Script Name text box.

Answer Key Step 2, page 9: 6.979 degrees Step 2, page 10: No Step 3, page 12: DV_p4_x (+4.78%) Step 4, page 12: DV_p2_x (-0.247%) Step 5, page 12: Step 8, page 13: Yes Step 3, page 14: X Y Point 1 -67.9272 52.9958 Point 2 -66.0366 20.787 Point 3 -50.1885 8.99757 -1 mm (degrees) Nominal +1 mm (degrees) Point 4x -3.1782 ~0 2.9428 Point 2x 1.5269 -1.554