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Step 5.4: MMA, Kinematic Function-Blocks, Graph FB

Contents

Basic Function-Blocks

In this Step, we review the:

•	The Master-Machine-Angle

•	Three of the basic Kinematic FBs that we use most frequently

•	Make a plot of motion-values with a Graph FB

The Master Machine Angle (MMA) 'Function-Block'

The Master-Machine-Angle is at the bottom and right of the application.

Master :

Machine :

Angle :

The machine clock that beats the drum for all Function-Blocks and Kinematic-Chains

It synchronizes all FB calculations

Equivalent to the angle of a shaft that rotates one time per machine cycle.

To edit the Master Machine Angle:

•	Enter an Exact Angle: Enter a value in the MMA data-value box. Use your keyboard to enter a new value or use the spin-box tool.

•	Enter an Approximate Angle: Drag your mouse-pointer inside the MMA scale area

Of course, when you Cycle the model, the Master Machine Angle continually increases from 0 to 360, again and again.

Basic Kinematic Function-Blocks

To add these Function-Blocks (FBs) to the graphic-area:

1.	Click the Function-Block you want to add to the model in the Add menu or the Kinematic-FB toolbar

2.	Click in the graphic-area.

The Function-Block is in the graphic-area.

The Linear Motion FB

The motion-values at the output-connector of the Linear-Motion FB increase linearly at the same rate as the MMA.

Linear-Motion FB Output Angle ψ(º) = Master-Machine-Angle(º) + θ(º)

Use a Linear-Motion FB to synchronize each kinematic-chain with the Master-Machine Angle.

Note: Kinematic-chains do not always move as a function of the Master-Machine-Angle.

The Gearing FB

The 'Gearing Function-Block' has three parameters:

The Gearing FB function is:

Output = {×(Input +)}+

•	Result 1 = add to the input-motion-value

•	Result 2: = multiply Result 1 with the Gearing Ratio

•	Result 3: = add to Result 2 = output motion-value

The Motion FB

We use a Motion Function-Block to link a motion in a Motion name-tab to a Motion-Part

To link the Motion FB to a Motion name

1.	Double-click the Motion FB to open the Motion FB dialog-box

2.	Select a Motion name in the drop-down list box

The list is a complete list of motion name that are in MotionDesigner Motion name-tabs

We design the motions in MotionDesigner, of course. You can design simple or complex motions in MotionDesigner.

Plot motion-values with a Graph FB

To find the motion-values at the output-connector of a FB, simply connect a wire from its output-connector to the input-connector of a Graph FB.

Remember, when you connect an output-connector to an input-connector with a wire, the motion-values are the same at the output-connector and the input-connector, because they see the same wire.

Linear Motion FB

STEP 1:

Add TWO Linear-Motion FBs to the graphic-area.

STEP 2:

Add a Graph FB to the graphic-area

STEP 3:

Connect a Linear-Motion FB to the X-axis input of the Graph FB .

STEP 4:

Connect a Linear-Motion FB to one of the Y-axis inputs of the Graph FB .

STEP 5:

Edit the Linear-Motion FB that is connected to Y-axis of the Graph FB.

STEP 6:

Edit the Machine Angle +'

(the phase relative to the MMA) parameter

STEP 7:

Edit the Graph FB to show the plot

Below: a screen capture of the various elements, cleverly positioned, after Steps 1–7.

There are two Linear-Motion Function-Blocks connected to a Graph FB.

Function-Blocks-LMFB

Note: the Linear-Motion FB in this image is old. However, the main parameter has not changed.

In the image to the left, the 'top' Linear-Motion FB is red. It is connected it to the top (Y1) input of the Graph FB, and the 'bottom' Linear-Motion FB is connected to the X-axis.

SETTINGS

The dialog for the 'top' Linear-Motion FB is open. The Machine Angle = +30

Master-Machine-Angle = 120

GRAPH CONNECTIONS:

X-AXIS -'bottom' Graph connection

The 'bottom' Linear-Motion FB is connected to the X-axis of the Graph FB.

The phase of the 'bottom' Linear-Motion FB is '0'.

Therefore, the motion value at the output-connector of the 'bottom' Linear-Motion FB, and the input to the X-axis of the Graph FB is:

= MMA

= 120

Y-AXIS – 'top' Graph connection

The 'top' Linear-Motion FB is connected to the Y1-Axis of the Graph FB.

The phase of the 'top' Linear-Motion FB is +30

Therefore, the motion value at the output-connector of the 'top' Linear-Motion FB, and the input to the Y1-Axis of the Graph FB is: =

MMA + Phase =

120 + 30 = 150

Digital Readouts (DROs)

The DROs below the graphs indicate the values at the position of the vertical red cursor

Gearing FB

STEP 1:

Add TWO Linear-Motion Function-Blocks to the graphic-area.

STEP 2:

Add a Graph FB to the graphic-area

STEP 3:

Connect a Linear-Motion FB to the Graph FB X-axis.

STEP 4:

Add a Gearing FB to the graphic-area

STEP 5:

Connect the other Linear-Motion FB to the Gearing FB, and from the Gearing FB to the Graph Y-axis.

STEP 6:

Double-click the Linear-Motion FB connected to the Gearing FB and edit the phase.

STEP 7:

Double-click the Gearing FB to edit the Gear parameters.

STEP 8:

Double-click the Graph FB to open it.

GearingFB-Explained

The Gearing FB dialog box is open

We have selected the Gearing as Ratio' option

We have entered:

•	20 = Input Pulley

•	10 = Output Pulley

•	20 = Add Before Gearing Ratio

•	10 = After Gear Ratio

Graph FB input-Connections

X-AXIS: The Linear-Motion FB is connected to the X-axis of the Graph FB

It equals the MMA = 120

Y-AXIS: The 'top' Linear-Motion FB is connected to the Gearing FB, which is connected to the Graph FB

The output of the Linear-Motion FB is +30

The input to the Gearing FB

= 120 + 30 = 150

The output from the Gearing FB and input to the Graph FB is:

= (20/10)*(120+30)+20)+10 = 350

The Digital Readout (DRO) lists the values of the variables connected to the Graph FB.

X-axis = 120; Y1-Axis = 350

For Information:

Gearing FB Output (when MMA 0) = 2 * ((0+30) + 20) + 10 = 110

Gearing FB Output (when MMA 360) = 2 * ((360+30) + 20) + 10 = 830

Motion FB

STEP 1:

Add TWO Linear-Motion Function-Blocks to the graphic-area

STEP 2:

Add a Graph FB to the graphic-area

STEP 3:

Connect one Linear-Motion FB to the bottom input-connector of the Graph FB - the X-axis.

STEP 4:

Add a Motion FB to the graphic-area

STEP 5:

Connect the Linear-Motion FB to the Motion FB, and from the Motion FB to the Graph FB.

STEP 6:

Double-click the Linear-Motion FB that is connected to the Motion FB and edit the phase

STEP 7:

Double-click the Motion FB to link it with Motion in MotionDesigner

STEP 8:

Open the Graph FB.

We have cleverly positioned the elements after we have followed the steps above.

QST6-2-3A Master-Machine-Angle (MMA) Slider @ is at 120.

Top

Linear-Motion FB >> Motion FB >> Y1 Graph FB

Connect

•	The 'top' Linear-Motion FB to the Motion FB to the Y1 input of the Graph FB

MotionDesigner is open

MotionDesigner shows the Motion that is linked to the Motion FB

The Motion 'Function' in MotionDesigner is the default motion – a Rise-Dwell-Return-Dwell.

Bottom

Linear-Motion FB >> Graph FB

The output of the Linear-Motion FB is equal to the Master-Machine-Angle (MMA). The MMA is 120

The DRO for the X-axis 120

The Graph shows a plot of output from the 'Motion FB' against the 'bottom' Linear-Motion FB

•	The MMA is 120

•	The 'top' Linear-Motion FB is 150

The motion graph shows that the Y-axis is still 100mm when the X-axis is 150.

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