Kinematic FB | Add Motion-Dimension FB

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Kinematic FB | Add Motion-Dimension FB

Motion-Dimension Function-Block?


See also Motion-Dimension dialog-box


Terminology

Motion-Part :

A Part whose position, relative to another Part, is specified by Motion-Dimension FB.

Rocker :

A Part whose Angle, relative to another Part, is specified by Motion-Dimension FB.

Slider :

A Part whose Distance, relative to another Part, is specified by Motion-Dimension FB.

Motion-Dimension FB :

A FB that specifies the position and the motion of a Part relative to another Part.

The two Kinematic States of Parts

Not kinematically-defined :

The state of a Part when it is not solved. It is has one or more degrees-of-freedom.

kinematically-defined :

The state of a Part when it is solved. It has zero degrees-of-freedom. Its position, velocity and acceleration are fully specified. It has a Mobility of Zero.

All Parts in the model must be KINEMATICALLY-DEFINED before you calculate any kinematic and kinetostatic (Force data).


Note: The Part-Outlines, when in the two kinematic states, have two different colors. This is to help you identify the two kinematic-states.

Motion-Dimension FB - the function

A Motion-Dimension FB identifies a Motion-Part.

A Motion-Dimension FB can specify, relative to a different Part, the:

Angle of a Part - which we then call a Rocker

- or -

Distance to a Part - which we then call a Slider

tog_minusMotion-Dimension FB - Rocker

Preparation: Motion-Dimension - Rocker (typical)

MD-ADDMOTIONDIM-ROCKER-01

Preparation example:

Two(2) Parts. In this case the Base-PartRed-14-1b and a rotating-PartRed-14-2

LinesRed-14-3Red-14-4 in each Part

Pin-JointRed-14-5 joins the start-Point and/or end-Points of each LineRed-14-3Red-14-4

PartRed-14-1b is kinematically-defined

PartRed-14-2 is not kinematically-defined


See Add Line, Add Part, Add Pin-Joint

Add Motion-Dimension FB (Rocker)

MD-ADDMOTIONDIM-ROCKER-01A

STEP 1: Select the Add Motion-Dimension FB command

Add Motion-Dimension FB

1.Click Kinematics FB toolbar > Motion-Dimension FB

or

1.Click Add menu > Add Motion-Dimension FB

 

MD-ADDMOTIONDIM-ROCKER-01

STEP 2: Select the three elements in the graphic-area (or Assembly-Tree)

Element #1: PIN-JOINT

1.Click a Pin-JointRed-14-5

The Pin-Joint must be a joint between two(2) Parts, and:

One Part must be a kinematically-defined Part

The other Part must be a free Part.


Elements #2 and Element #3: Lines Red-14-3Red-14-4

Each Line must be a child to a Point that is also a child to the Pin-Joint. (Element #1)

2.Click the LineRed-14-4 in the kinematically-defined PartRed-14-5

3.Click the LineRed-14-3 in the free PartRed-14-2

STEP 3: Complete the Command

1.Click OK-tiny-11-15 in the Command-Manager to complete Add Motion-Dimension FB (Rocker).

 

MD-ADDMOTIONDIM-ROCKER-01B
MD-ADDMOTIONDIM-ROCKER-01C

Result:

PartRed-14-3 is now a Part that is kinematically-defined.

A Motion-DimensionRed-14-1b and Motion-Dimension FBRed-14-2 specifies the angle between the Lines

MD-Icon-FB-MotionDimension-Rocker--inGA

The Motion-Dimension FB iconRed-14-2 in the graphic-area for a Rocker.

Note: In the graphic-area the:

To move the Motion-DimensionRed-14-1b : CTRL+ Drag the FB iconRed-14-2

To move the Motion-Dimension FBRed-14-2 : Drag the FB iconRed-14-2

To edit

STEP 3: Open the dialog-box - See Motion-Dimension dialog-box

Kinematics Tree - Motion-Dimension (Rocker)

MD-ADDMOTIONDIM-ROCKER-01D

When we add a Motion-Dimension FB to a Pin-Joint, we identify it as a Rocker in the Kinematics-Tree.

The kinematic elements are:

Part +

Pin-Joint +

Motion-Dimension = ROCKER


tog_minusMotion-Dimension FB and Slider

Preparation: Add Motion-Dimension - Slider (typical)

MD-ADDMOTIONDIM-SLIDER-01

Preparation example:

1.Two(2) PartsRed-14-1bRed-14-2  

One is a kinematically-defined Part ...the Base-PartRed-14-1b

The other is a free Part Red-14-2

2.The Parts are Joined... with a Slide-JointRed-14-3

3.Start PointRed-14-4 (or end-Point) of a Line in the kinematically-defined Part

4.start-PointRed-14-5 (or end-Point) of a Line in the free Part

The Lines are those that you select for the Slide-JointRed-14-3.


See Add Line, Add Part, Add Pin-Joint


Add Motion-Dimension FB (Slider)

MD-ADDMOTIONDIM-SLIDER-01A

STEP 1: Add the Motion-Dimension FB

Add Motion-Dimension FB

1.Click Kinematics FB toolbar > Motion-Dimension FB

or

1.Click Add menu > Add Motion-Dimension FB

 

MD-ADDMOTIONDIM-SLIDER-01

STEP 2: Select three elements in the graphic-area (or Assembly-Tree)

Element #1: PIN-JOINT

1.Click a Slide-JointRed-14-3

The Slide-Joint must be a joint between two(2) Parts, and:

One Part must be a kinematically-defined Part Red-14-1b

The other Part must be a free Part Red-14-2


Elements #2 and Element #3: POINTS Red-14-4Red-14-5

Each Point must be a child to a Line that is also a child to the Slide-Joint. (Element #1)

2.Click the PointRed-14-4 in the kinematically-defined PartRed-14-1b

3.Click the PointRed-14-5 in the free PartRed-14-2

STEP 3: Complete the Command

1.Click OK-tiny-11-15 in the Command-Manager to complete Add Motion-Dimension FB (Slider).

Result :

The free Part is now kinematically-defined.

A Motion-DimensionRed-14-1b and Motion-Dimension FBRed-14-2 specifies the angle between the Lines

MD-Icon-FB-MotionDimension-Rocker--inGA

The Motion-Dimension FB iconRed-14-2 in the graphic-area for a SLIDER.

Note: To drag in the graphic-area the:

Motion-Dimension : CTRL+ Drag the FB icon

Motion-Dimension FB : Drag the FB icon


STEP 4: Open the dialog-box - See Motion-Dimension dialog-box

MD-ADDMOTIONDIM-SLIDER-01B

MD-ADDMOTIONDIM-SLIDER-01C

Kinematics Tree - Motion-Dimension (Slider)

MD-ADDMOTIONDIM-SLIDER-01D

When we add a Motion-Dimension FB to a Slide-Joint, we identify it as a Slider in the Kinematics-Tree.

The kinematic elements are:

Part +

Slide-Joint +

Motion-Dimension = SLIDER


Videos: Add Part, Add Joint, Add Motion-Dimension FB:

Add Motion-Dimension FB to a Pin-Joint

Add Motion-Dimension FB - Rocker

 


Add Motion-Dimension FB to a Slide-Joint

Add Motion-Dimension FB - Slider

Add Motion-Dimension FB - Slider

 

Add Motion-Dimension FB - Slider

 


Special Methods

Frequently, in a machine, joints are coincident (co-axial).

For example, there are two or more rotating-Parts that rotate about one center, or two or more sliding-Parts that slide along one axis.

Special Method: Coincident Pin-Joints

If you want to specify the motion of each rotating-part with a different Motion-Dimension FB, you must carefully plan as to which Points you select when you add the Pin-Joints,

Then, when you add the Motion-Dimension FBs, the Motion-Dimensions can reference the correct Parts.

Special Method: Coincident Slide-Joints

If you want to specify the motion of each sliding-part with a different Motion-Dimension FB, you must carefully plan as to which Lines you select when you add the Slide-Joints,

Then, when you add the Motion-Dimension FBs, the Motion-Dimensions can reference the correct Parts.

The Lines you select when you add the Slide-Joint determine between which two Parts you can specify the Motion-Dimension FB.


Special Method 1:

MD-ADDMOTIONDIM-ROCKER-02M

Result of Special Method 1:

The model shows

Two Motion-Dimension FBs

They reference the same Line in the Base-Part.

You can see the dimension of the two Motion-Dimensions FBs start at the green horizontal Line.

btn_delkeywordSTEP 1: Add Pin-Joints two times
btn_delkeywordSTEP 2: Add Motion-Dimension FB two times

Special Method 2:

MD-ADDMOTIONDIM-ROCKER-03A

Result of Special Method 2

We want the two Motion-Dimensions FBs:

Motion-Dimension 1:

From the Line in the Base-Part

To a Line in 'Part 1'

Motion-Dimension 2:

From the Line in 'Part 1'

To the Line in 'Part 2'

btn_delkeywordSTEP 1: Add Pin-Joint two times
btn_delkeywordSTEP 2: Add Motion-Dimension FB two times

btn_delkeywordPositive' Direction of Slide-Joints and Slider

The nursery rhyme : She swallowed a cat, that swallowed a mouse, that swallowed a spider, that swallowed a fly... will come to mind.