Objective of this Step
In this step, we specify the motion to the Part to be Constant-Angular Velocity.
We also learn how to connect wires from output-connectors to input-connectors of different FBs [Function-Blocks].
See also:
In MechDesigner, a Motion-Part has its motion defined by the input to a Motion-Dimension FB. A Rocker is Motion-Part that may rotate continuously or oscillate back and forth. It is the Rocker kinematic-element in the Kinematics-Tree.
In a Machine, a Rocker is a nearly always a machine element that 'oscillates back and forth'.
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Terminology Reminder:
| • | kinematically-defined Part : a part that has zero-degrees of-freedom. |
| • | Connect a wire : to 'drag a wire from the output-connector of a Function-Block to the input-connector of a different Function-Block. |
| • | Motion-Values flow instantly along the wires from FB to FB |
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Summary of this Step
| 1. | Review the Kinematic-FBs, the Master-Machine-Angle, the Animation-Speed. |
| 2. | Add a Linear-Motion FB - also called a 'Clock'. |
| 3. | Connect a wire from the output-connector of the Linear-Motion FB to the input-connector of the Motion-Dimension FB. |
| 5. | Add, connect and edit a Gearing FB to rotate the Part in a clockwise direction. |
Video
Video of this Step
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How to...Add a Linear-Motion FB and join the FBs with wires'
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We use
| • | Use Kinematic Function-Blocks to give motion-values to and |
| • | Connect wires between Function-Blocks (FBs) from output-connectors to the input-connectors of a different Function-Block. |
The schematic, to the left, shows how you can connect wires between the Function-Blocks.
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Motion-Providers: have output-connectors. The motion-values are either the MMA or found from the motion of a Part or Point in a kinematically-defined chain.
Motion-Processors: use the motion-values from Motion-Providers as the independent variable for their internal function. You can actively design their functions.
Motion-Parts: are identified by Motion-Dimension FB. The Motion-Parts have their motion specified by the motion-values at the input-connector to the Motion-Dimension FB.
Motion-Points: are identified by a Motion-Path FB. The Motion-Points have their motion specified by the motion-values at the input-connector to the Motion-Path FB.
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Tutorials Steps:
Add a Linear Motion FB; Connect to the Motion Dimension FB
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| STEP 1: | Click [right of the graphic-area]
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Click
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Right-click in the graphic-area, and select the Linear-Motion FB icon in the contextual-menu. |
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| STEP 2: | Click in the graphic-area. |
MechDesigner adds the Linear-Motion FB to the graphic-area.
Put the Linear-Motion FB to the left of the Motion-Dimension FB. It is easier to connect the FBs together.
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| STEP 3: | Connect Function-Blocks with a 'wire' . |
See how:
The motion-values at the output-connector of the Linear-Motion FB are at the the input-connector of the Motion-Dimension FB.
The Motion-Dimension = Output from Linear-Motion FB + Base-Value of the Motion-Dimension FB
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Cycle the kinematic-chain.
| STEP 4: | Click Run toolbar > Cycle icon
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Click Run menu > Cycle
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Press the 'C' key on your keyboard to start and stop the cycle command. |
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The Crank rotates one time with each Machine Cycle. Watch the red pointer under the Master-Machine-Angle move from 0 to 360 each time the Part rotates one time.
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Rotate the Part in a Clockwise direction
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As motion-values increase from 0 to 360, the Crank rotates in a counter-clockwise direction. Thus, the positive kinematic direction of an angle is the counter-clockwise direction.
To rotate the Crank in a clockwise direction, we will use a use a Gearing FB [I prefer to use the Gearing FB].
| STEP 2: | Click in the graphic-area. |
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Delete the wire between the Linear-Motion FB and the Motion-Dimension FB
To delete a wire:
| 1. | Click the wire in the graphic-area |
| 2. | Click your 'delete' on your keyboard, our use the method in the Selection-Window |
Connect the Linear-Motion FB to the Gearing FB, and the Gearing FB to the Motion-Dimension FB
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Step 4 is complete
Now we can open the Gearing FB dialog-box
| STEP 5: | Double-Click the Gearing FB |
| STEP 6: | Edit the Gearing Ratio parameter to -1. |
| STEP 8: | Click
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Press the 'C' key on your keyboard |
The Crank now rotates in a Clockwise direction.
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Other Notes:
Master Machine Angle (MMA)
 Master Machine Angle in the Feedback Area
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Revs: [Read-Only] box is a counter for each time the machine angle progressives from 0 to 360.
Pointer (▲): below the MMA scale, indicates the Master-Machine-Angle approximately
Machine Angle [Read/Write] indicates the Master Machine Angle exactly.
To edit the Master-Machine-Angle:
Approximately : Drag, to the left or right, with your mouse-pointer inside the Gold Area of the scale
Exactly : Enter a new value with keyboard in the Read/Write box.
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Animation Speed
 Animation Speed Slider in the Feedback Area |
Edit the Animation-Speed
The Animation-Speed does not change kinematic results.
| • | Drag, to the left or right, with your mouse-pointer inside the area of the scale |
Edit the Simulation-Speed
The Simulation-Speed does change the kinematic results.
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