Tutorial 5: Edit the Start of Traditional Motion-Law

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Tutorial 5: Edit the Start of Traditional Motion-Law

Edit the Start of a Traditional Motion-Law

With a Traditional Motion-Law you can control its Start-Position and its End-Position.

You CANNOT (usually) edit the Velocity, Acceleration, or Jerk at the Start and End of a Traditional Motion-Law.

The velocity and acceleration values are usually zero at the Start and End of a Traditional Motion-Law.

See Standard or Traditional Segments

In this Tutorial, we show you how to edit the Start-Position of a Traditional Motion-Law with the Blend-Point Editor.

The mathematical function of the Traditional Motion-Law controls the Velocity, Acceleration, and Jerk values.

We consider the two cases:

How to edit the position at the start of a Traditional Motion-Law when:

Case 1: The motion-law of the Previous-Segment is also a Traditional Motion-Law.

Case 2: The motion-law of the Previous-Segment is a Dwell Motion-Law.

VIDEO

 

 

btn_delkeywordCASE 1: Previous-Segment is a Traditional Segment
GST-T5-001

In the image above, the:

Red-14-1b Selected-Segment (RED) is Modified-Trapezoidal - a Traditional Motion-Law.

Red-14-2 Previous-Segment is Modified-Sinusoid - also a Traditional Motion-Law.
Start Blend-Point Editor

Start Blend-Point Editor

To enter the Position at the End of the Modified-Sinusoid Red-14-2

- when it is also the Position at the Start of the Modified-TrapezoidRed-14-1b

1.Click above or below Modified-Trapezoid segmentRed-14-1b. It becomes the Selected-Segment

2.Click the Blend-Point and Segment toolbar > Start Blend-Point Editor icon
Y-axis values: Position Values in the Blend-Point Editor

Y-axis values: Position Values in the Blend-Point Editor

In Y-axis Values of the Blend-Point Editor (see image above)

3.Make sure the Specify End Position control-button is active Red-14-3

4.Make sure the Match control-button is active Red-14-4

5.Edit the End-PositionRed-14-5 with the Spin-Box tool, or use your keyboard to enter a new motion value.

The End-Position value is the position at the end of the Modified-SinusoidRed-14-2 segment and not the End-Position of the Modified-TrapezoidalRed-14-1b segment.

CASE 1 is easy and the normal case.

Question:

Why are the Velocity, Acceleration, and Jerk Control Buttons disabled in the Blend-Point Editor.

Answer:

You cannot edit those values. The motion-derivatives are defined by the mathematical function for the Modified-Sinusoid and Modified-Trapezoid segments. The Velocity and Acceleration values are zero by definition of the mathematical function - the Motion-Law.
btn_delkeywordCASE 2: The Previous Segment is a Dwell Motion-Law
GST-T5-002

In the image above, the:

Red-14-1b Selected-Segment (RED) is Modified-Trapezoidal - a Traditional Motion-Law.

Red-14-2 Previous-Segment is Dwell - also a Traditional Motion-Law.
Start Blend-Point Editor

Start Blend-Point Editor

To edit the Position at the End of the Dwell Red-14-2

- when it is the Position at the Start of the Modified-Trapezoid Red-14-1b

1.Click the Modified-Trapezoid segmentRed-14-1b. It becomes the Selected-Segment.

2.Click the Blend-Point and Segment toolbar > Start Blend-Point Editor icon
Blend-Point Editor Y-axis Position Values MODIFIED-TRAPEZOIND is the Selected-Segment

Blend-Point Editor Y-axis Position Values
MODIFIED-TRAPEZOIND is the Selected-Segment

In the Y-axis Values separator of the Blend-Point Editor :

The End-Position control-buttonRed-14-2 and the Start-Position control-button are READ-ONLY.Red-14-1b

You cannot enter a value in their data-boxes !

Remember:

Start-Position = Start of the Selected-Segment (the Modified-Trapezoid)

End-Position = End of the Previous-Segment (the Dwell)

Why are the data-boxes and Control-Buttons for the End-Position READ-ONLY?

Definition 1 :

DWELL: Position at End of Dwell = Position at the Start of Dwell

Rule 1 :

Dwell: You must edit the Start-position of the DWELL segment

GST-BPE-Goto-PreviousSEgment

Rule 1:

Select the Dwell segment

3.Click the Move to the Previous-Segment icon in the Blend-Point Editor.

Blend-Point Editor Y-axis Position Values DWELL Segment is the Selected-Segment

Blend-Point Editor Y-axis Position Values
DWELL Segment is the Selected-Segment

The Dwell segment is now the Selected-Segment.

We cannot edit its Start-PositionRed-14-1.

Again, why?

Rule 2 :

If the Match control-buttonRed-14-2 is active (and the Dwell segment is still the Selected-Segment)

... you must edit the End-PositionRed-14-3 for the segment that is the Previous-Segment to the Dwell segment

 

4.Use the Spin-Box (or enter a value with your keyboard) to edit the End-PositionRed-14-3 of the Previous-Segment.

In the image below, the:

End-Position=100Red-14-3

Notice :

Start-PositionRed-14-1 (of the Dwell Segment) = 100

This is because the Match control-buttonRed-14-2 is active.
Blend-Point Editor Y-axis Position Values DWELL Segment is the Selected-Segment

Blend-Point Editor Y-axis Position Values
DWELL Segment is the Selected-Segment

SUMMARY: How you must edit the Start of a Traditional Motion-Law when the Previous Segment is a Dwell.

Select the Dwell segment ...

... edit the End-Position of the Previous-Segment to the Dwell.

When the Match control-button is active in the Dwell segment

automatically, the Start-Position of the Dwell segment will equal the End-Position of the Previous segment.

And, from the mathematical function of a Dwell segment (a very simple function, you will agree)

automatically, the End-Position of the Dwell segment will equal the Start-Position of the Dwell segment

And, when the Match control-button is active in the Modified Trapezoid segment:

... automatically, the Start-Position of the Modified-Traditional segment will equal the End-Position of the Dwell segment