WORKSHOP 13 SUSPENSION-STEERING SYSTEM

Workshop Objective Assemble a suspension-steering system and inspect the toe angle that the wheel exhibits at steering wheel angles of 45º, 0º, and -45º. Quiz students about the steps required to complete the workshop.

Problem description Software Version Files Required You will use the following two models in this workshop: A geometric representation of a short-long arm (SLA) suspension subsystem. A geometric representation of a rack-and-pinion steering system. The rack-and-pinion steering model is constrained as shown next: Software Version Adams 2013 Files Required Use file exercise_dir/mod_12_suspension_2.

Suggested Steps Import the model and change the directory. Import the Steering model. Constrain the steering model. Add motion and couple to the joints. Assemble the suspension and steering models. Verify the model. Delete unwanted joints. Simulate models and compare results. Compare the results. Save your work.

Step 1. Import Model and Change Directory To import a model: Select Existing Model and start Adams/View from the directory exercise_dir/mod_12_suspension_2. From this directory, open the model that you created in the previous module. If you need a fresh copy of the model, change your working directory to exercise_dir/mod_12_suspension_2/completed, then open the command file, suspension_2_completed.cmd. To change the working directory to exercise_dir/mod_13_susp_steer: From the File menu, select Select Directory. Change to exercise_dir/mod_13_susp_steer. a b

Step 2. Import the steering model Import the steering model, shown below. It is in the command file steering_parts_start.cmd. The file contains a model named rack_and_pinion_steering.To import the model: Import the Adams/View model command file steering_parts_start.cmd.

Step 3. Constrain the Steering Model Now you’ll constrain the steering model. Each time you add a modeling element, you’ll simulate the model to verify its movement. To constrain the steering model: Apply a rotational joint motion to the revolute joint, strwheel_body_rev, on the steering_wheel_column. a

Step 4. Add Motion and Couple Rotation Right-click the motion icon, point to Motion: MOTION_1, and then select Modify. In the Function (time) text box, enter the following function: 45d*sin(360d*time) (be sure that Type is set to Displacement). Run a one-second, 50-step simulation. b The difference between merging two models and assembling models is found in the Adams/View Command Language help: Adams/View > View Command Language > model > model assemble.

Step 4. Add Motion and Couple Rotation (Cont.) Use the Coupler tool to couple the rotation (strshft_body_cyl) of the steering_shaft with the translation (rck_body_trans) of the steering_rack. Right-click the coupler icon, point to Coupler: COUPLER_1, and then select Modify. Modify the coupler so that for every 7º of rotation the steering_rack travels 1 mm: To verify that the steering_rack travels as expected, simulate the model. a Coupler b c

Step 5. Assemble the Suspension and Steering Models c Assemble the rack_and_pinion_steering model with the suspension model: From the Tools menu, select Command Navigator. In the Command Navigator, double-click model, and then double-click assemble. Name the model steering_suspension. Right-click the Model Names text box, point to Guesses, and then select *. Selecting * prompting Adams/View to include in the text box every item that is displayed under the Guesses option. To display the assembled model, from the View menu, select Model. Double-click steering_suspension. a b e f

Step 5. Assemble the Suspension and Steering Models (Cont.) Your model should look like so (shading turned on): a

Step 6. Verify the Model a a b c Verify the model to ensure it is not overconstrained. To ensure that the model is not overconstrained, look for duplicate joints as explained next. To verify the model: From the Tools menu, select Database Navigator. Set the top pull-down menu in the Database Navigator to Graphical Topology. Double-click the new model name, steering_suspension, and then select body_ground. a b c

Step 7. Delete Unwanted Joints Delete the unwanted joints by right-clicking them from the Model Browser and selecting Delete: Delete the fixed joint between body_ground and ground, (body_grnd_fixed_2). Delete the fixed joint, (rck_body_joint) between body_ground and steering_rack. Note: Leave both the rotational motion and the revolute joint between body_ground and steering_wheel_column because both are needed. To redisplay the measures you created in Create measures, in Workshop 12, slide 6, from the ribbon Design Exploration, select Display a Measure . Select both measures, Wheel_Height and Toe_Angle. (both measure graphs will appear) c d b

Step 8. Simulate and Compare In this section, you’ll run three simulations, each with different steering wheel angles. You’ll then compare the results of the simulations. To run and compare a series of simulations: Modify the motion you created in Step 4 on slide 9 to be a constant 45º steering wheel angle (Displacement(time) = 45d). Simulate the model. Save the simulation results as right_turn. Save the results just as you did in To save the simulation results in Workshop 2 - Adams/View Interface Overview, slide 16. Run a simulation with a 0º steering wheel angle (Displacement(time) = 0d). Save the simulation results as straight. Run a simulation with a -45º steering wheel angle (Displacement(time) = -45d). Save the simulation results as left_turn. Launch Adams/PostProcessor. a c d e f g

Step 9. Compare Results Plot toe_angle versus wheel height for all three simulations, on the same plot. (as done in the last workshop) a

Step 10. Save Your Work To save your work: Save the database so you retain the analyses. Exit Adams/View.

Workshop 13, Review What information do you need to provide Adams/View to create a coupler? ______________________________________________________________________________________________________________ What is the default name that Adams/View assigns to simulation results? ______________________________________________________________________________________________________________