Kinematic Analysis Tools

We use these tools to show kinematic values at Master-Machine-Angle[MMA].

We can also plot the kinematic values for a complete machine cycle with a Graph FB.

tog_minus        Tool 1: Element Properties dialog-box                                                        

This dialog-box shows the Element's Properties. The values are at the Master-Machine-Angle [MMA]. You can move the model to any MMA while this dialog is open.

Elements that have Element Properties are:

Wire, Part, Pin-Joint, Slide-Joint, 2D-Cam, Part-Outline, Line, Circle, Arc, Point, Gear-Pair, Function-Blocks...

Example: The 'Point Element Properties' dialog-box is about to be opened to show its kinematic-properties.

To show the Elements Properties dialog-box:

In the graphic-area:

1.Hover above an element so that it becomes Red... do not click the element
2.CTRL key down + Click the element

The 'Element-Properties dialog-box' ['Properties' in title-bar of dialog] is now open.


The two steps above are frequently described as one step: 'Hover+CTRL+Click'.


Notes:

If you Hover+Ctrl+Click more than one element, the Element Properties dialog-box will not open.
Properties dialog box for a Point

Element Properties dialog box for a Point

For Example: Element Properties of a Point.

In the image of the Parts and Lines at the top, we looking at the 'Element's Properties of a Point'.

At the top of the dialog-box, you can see the Element's Name [Point19], Element's Part [Part3], and Element's Mechanism [Mechanism].

In this case, we are looking at the Element Properties of 'Point19', which is a child to 'Part3' [Element's Part], which is a child to 'Mechanism' [Element's Mechanism].

Point Property:

In the case of a Point, the properties are:

'Part Pos': the Point's vector position within the coordinate-system of the Part.
'Mech Pos': the Point's vector position within the coordinate-system of the Mechanism-Editor.
'Glob Position': the Point's vector position within the coordinate-system of the Model-Editor.
'Velocity', 'Acceleration':
oi , j : the magnitude of the vector's Velocity and Acceleration , in the X and Y directions, respectively
o|n| : the total magnitude of the vector's Velocity and Acceleration
oΘ :  the direction of the vector's Velocity and Acceleration . ['0' is the X-axis direction of the Mechanism-Plane]

'V' indicates they are 'vector' values.

tog_minus        Tool 2: Trace-Points                                                                                    

The Trace-Point shows the path of a Point on the Mechanism-Plane for a complete machine cycle.

Other terms for a Trace-Point are: 'locus', 'curve', and sometime a 'coupler curve'.

It is only possible to show a Trace-Point of a Point when the:

Part is a kinematically-defined chain, or as a Green Part-Outline.
Point actually moves relative to the Mechanism-Plane.

You can show any number of Trace-Points.

Add Trace icon

To show a Trace-Point:

1.Click Add Trace-Point in the Kinematic-elements toolbar
2.Click a Point that is a child to a Part in a kinematically-defined chain
3.Click OK in the Command-Manager

Do 1-3 again for other Points that belong to the same or different Parts.

Note: SHORT-CUT: 1: Click Add Trace-Point ; 2: Right-Click a Point. The Trace-Point will show immediately. Do 1-2 again to add more Trace-Points.

Video : Add Trace-Point

NOTES: SELECT-ELEMENTS DIALOG-BOX

When there is more than one Point that are coincident to each other, the Select Elements dialog-box opens.

1.Click a Point in the Select Elements dialog-box
2.Click OK to close the Select Elements dialog-box
3.Click OK in the Command-Manager

Do 1-3 again for other Points. Even in the same Part.

When the Points are in the same Part, or they are made coincident with a Pin-Joint, then the Point you select is not important.

To delete a Trace-Point

1.Click the Trace-Point in the graphic-area so that it becomes RED, and also shows in the Selection-Window
2.Click the 'delete' button on your keyboard,

- or -

2.Right-click the Point in the Selection-Window
3.Click 'Delete' in the contextual-menu

See also Mechanism Synthesis


Note: If the Point:

1....is a Point sketch-element (and not a Point that is start-Point, end-Point, centre-Point of another sketch-element)
2....is, also, not constrained with a dimension or constraint in the Part-Editor
3....is, also, a Trace-Point...

...then, you can drag the Point in the Mechanism-Editor and watch the Trace-Point update.

The Point must satisfy ALL of 1 ,2 & 3 before it is possible to drag the point.

tog_minus        Tool 3: Kinematic Vectors: Velocity and Acceleration

Point Kinematic Vector Display and Point Coordinates dialog box

To Show or Hide a Point's Velocity and Acceleration Vectors:

In the graphic-area:

1.Double-click a Point on a Part that has a Green Part-Outline

The Point: Vectors and Position dialog-box opens.

2.Click the Show or Hide Vectors separator bar
3.Click the Show Velocity Vector or Show Acceleration Vector, or both, check boxes
4.Click the TickSmall button to close the dialog-box.

Do 1-3 again to show the kinematic vectors of different Points, or to hide vectors for those Points that show vectors.


Note 1:

If necessary, change the colour of the graphic-area to see the vectors more clearly.

Application Settings > Colours tab > Graphic Colors > 'Background' button. .

Note 2:

You can double-click a velocity or acceleration vector to open this dialog-box.

Cycle (shortcut C) to see the vectors.

About the Velocity and Acceleration Vectors in the graphic-area

They show only when the Point moves relative to the Mechanism-Plane
Their length is proportional to the Point's instantaneous Velocity and Acceleration.
The magnitude of the vectors shows at the arrowhead of each vector in WHITE!
The colour of each is Blue for Velocity, Red for Acceleration
Update values and length each step as in the Machine Settings dialog-box.

Velocity and Acceleeration Vectors from a Point.

To scale the vectors:

Force, Torque, Velocity, Acceleration Buttons to scale the vectors.You can stretch or shrink the length of the vectors. Click the Velocity and the Acceleration (Accel.) buttons in the Feedback-Area.

1.Click the up-button to increase the length of the vectors

- or -

1.Click the down-button to decrease the length of the vectors

You many need to repeat this many times.

Top-Tip - make the vectors very short to see only the magnitude of the motion-values near to the Point.

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd