<< Click to Display Table of Contents >> Navigation: Getting Started Tutorials - MechDesigner > Tutorial 5: Kinematic Function Blocks for Motion > Step 5.4: MMA, Kinematic Function-Blocks, Graph FB |
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 is at the bottom and right of the application.
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. |
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 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.
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The 'Gearing Function-Block' has three parameters:
•Result 1 = add •Result 2: = multiply Result 1 with the Gearing Ratio •Result 3: = add |
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. |
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.
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 +' STEP 7: Edit the Graph FB to show the plot |
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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. |
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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 SETTINGS The dialog for the 'top' Linear-Motion FB is open 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 |
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. |
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 |
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 |
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. |
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We have cleverly positioned the elements after we have followed the steps above. |
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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. |
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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 •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. |