Objective of this Step

In this step, we specify the motion to the Part as Constant Angular Velocity - also termed Uniform Rotation Motion.

We also learn how to connect wires from output-connectors to input-connectors of different FBs (Function-Blocks).

See also: How to Connect Function-Blocks

In MechDesigner, a Motion-Part has its motion defined by the input to a Motion-Dimension FB and the Base-Value parameter defined in its dialog-box.

A Rocker is the kinematic name in the Kinematics-Tree for a Motion-Part that may rotate continuously or oscillate back and forth.

In a Machine, a Rocker is a nearly always a machine element that 'oscillates back and forth'.

Terminology Reminder:

kinematically-defined Part : a part that has zero degrees of-freedom.
FB : a Function-Block.
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 wires from FB to FB

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
4.Delete the wire
5.Add, connect and edit a Gearing FB to rotate the Part in a clockwise direction



Tutorial 1: Step 1.7

Start the Part-Editor
Edit Length of a Part


Video of this Step

How to add a Linear-Motion FB and join the FBs with wires'

Kinematic Function-Blocks

Schematic of Function-Blocks


Use Kinematic Function-Blocks to give motion-values to Motion-Parts and Motion-Points
Connect wires between Function-Blocks (FBs) from output-connectors to the input-connectors of a different Function-Block.

The schematic, to the left, attempt to show how you can connect wires between the Function-Blocks.

Motion-Provider: have output-connectors. The motion-values are either the MMA or found from the motion measurement of a Part or Point in a kinematically-defined chain.

Motion-Processor: use the motion-values from Motion-Providers as the independent variable for their internal function. You can actively design their functions.

Motion-Part: identified by Motion-Dimension FB. Its motion is specified by the motion-values at the input-connector to the Motion-Dimension FB.

Motion-Point: identified by a Motion-Path FB. Its motion is specified by the motion-values at the input-connector to the Motion-Path FB.

Tutorials Steps:

Add a Linear Motion FB; Connect to the Motion Dimension FB


STEP 1: Click Kinematic-FB toolbar > Linear-Motion FB (right of the graphic-area)
- or -
Click Function-Block menu > Add Linear-Motion
- or -
Right-click in the graphic-area, and select the Linear-Motion FB icon in the contextual-menu.


STEP 2: Click in the graphic-area.

MechDesigner adds the Linear-Motion FBRed-14-1b to the graphic-area.

Hover+Drag the Linear-Motion FB in the graphic-area to the left of the Motion-Dimension FB.

It is easier to connect the FBs together.


STEP 3: Connect Function-Blocks with wires.

See how: Connect Function-Blocks

The motion-values at the output-connector of the Linear-Motion FB are now also at the input-connector of the Motion-Dimension FB.

The Motion-Dimension = Output from Linear-Motion FB + Base-Value - see Motion-Dimension dialog-box


Cycle the kinematic-chain.

STEP 4: Click Run toolbar > Cycle icon
- or -
Click Run menu > Cycle
- or -
Press ALT+C keys on your keyboard to start and stop the cycle command.

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.

Rotate the Part in a Clockwise direction


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 1: Click Kinematic-FB toolbar > Add Gearing FB
STEP 2: Click in the graphic-area.


STEP 1: 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, or use the method in the Selection-Window
STEP 2: Connect the Linear-Motion FB to the Gearing FB, and the Gearing FB to the Motion-Dimension FB




Now we can open the Gearing dialog-box

STEP 5: Double-Click the Gearing FB
STEP 6: Edit the Gearing Ratio parameter to -1.
STEP 7: Click OK-tiny-11-15 to close the Gearing Dialog-Box.
STEP 8: Click Run toolbar > Cycle icon
- or -
Run menu > Cycle
- or -
Press the ALT+C key on your keyboard

The Crank now rotates in a Clockwise direction.

Other Notes:

Master Machine Angle (MMA)

Master Machine Angle Indicator

Master Machine Angle in the Feedback Area


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 above the MMA scale.

Exactly : Enter a new value with keyboard in the Machine Angle box.

Animation Speed

Animation Speed Slider

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 above the Animation-Speed Slider scale.

Edit the Simulation-Speed

The Simulation-Speed will change the kinematic results.

Use the Edit menu (or toolbar) > Machine Settings > Machine Speed.

Tutorials and Reference Help Files for MechDesigner and MotionDesigner 14.2 + © Machine, Cam, Mechanism, and Motion Design Software by PSMotion Ltd