<< Click to Display Table of Contents >> Navigation: Getting Started Tutorials - MechDesigner > Tutorial 2A: Four-bar Kinematic-Chains > Step 2.2: Add a Motion FB; Kinematic Vectors |
In Step 1.6, the model is a Motion-Part that rotates with uniform angular velocity - it is a Crank.
However, Parts in packaging machines frequently have more complex motions.
We use a Motion FB to link a more complex motion in MotionDesigner to a Motion-Part in the model.
1.Move a Part with a motion that is more complex than constant angular velocity
2.Show the Kinematic-Vectors for a Point
1.Delete the Gearing FB between the Linear-Motion FB and the Motion-Dimension FB
2.Add a Motion FB to the graphic-area.
3.Connect a wire from the Linear-Motion FB to the Motion FB, and from the Motion-FB to the Motion-Dimension FB
4.Edit the Motion-Dimension FB.
5.Edit a Point to show its Kinematic Vectors.
You should also complete MotionDesigner Tutorials 2 and Tutorial 3 to change the motion design.
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STEP 1: Delete the Gearing FB To delete the Gearing FB
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STEP 2: Add a Motion FB to the graphic-area To add the Motion FB
The Motion FB |
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STEP 3: Connect wires between the Function-Blocks See also: How to connect wires between FBs
In the image, there is wire
STEP 4: Cycle the kinematic-chain with the ALT+C key on your keyboard. The Rocker moves, with the motion as specified in MotionDesigner. It completes one motion for each cycle (0 – 360) of the Master-Machine-Angle. |
We are about to demonstrate that MechDesigner calculates the Position, Velocity and Acceleration of all Points at all times. We will add a new Line to the Coupler, at a random place, and show its velocity and acceleration vectors. |
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STEP 1: Add a Line to the coupler We use the same procedures to edit all Parts - we Edit the Part with the Part-Editor. There are many ways you can start the Part-Editor- See Step 1.3 Edit the Coupler Part:
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STEP 1: Show the Velocity and Acceleration Vectors:
Do 1-3 again to show the kinematic vectors of different Points, or to hide vectors for those Points that show vectors. Note: Why Show Numerical Vectors? There is no need to show them! And their values are slightly different from the normal Velocity and Acceleration Vectors. We calculate the Numerical Vectors with a finite difference technique, and we evaluate Velocity and Acceleration Vectors with algebraic equations. To reduce the differences, edit, by a small amount, the machine-angle. Use the Spin-Box tool of the Read-Write, Master-Machine Angle edit box. |
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Scale the Vectors
About the Velocity and Acceleration Vectors in the graphic-area
Notes: If necessary, change the color of the graphic-area to see the vectors more clearly - see Edit menu >Application Settings > Colors tab > Graphic separator > Background |