Tutorial: Building a Pick and Place Model with the CAD Toolbox
In this tutorial, you will build a pick and place mechanism from a .step file by performing the following tasks:
Import the CAD drawing
Group parts into groups
Add Coords and then import the CAD subsystems into MapleSim
Build the pick and place model
Simulate the model
From the File menu, select Load CAD....
Browse to the following directory:
C:\Program Files\Maple <RELEASE>\toolbox\CadToolboxPro\examples
where <RELEASE> is the major release version for Maple, for example, 2019
Note: This assumes that your Maple installation directory is C:\Program Files\Maple <RELEASE>\. If you installed Maple in a different location, replace C:\Program Files\Maple <RELEASE>\ with the correct location.
Select the PickAndPlace.step CAD file, and then click Open.
The CAD Toolbox window opens and a progress bar shows import progress.
When the import process is finished, the parts included in the assembly are shown in the CAD Toolbox window.
Orient the CAD assembly in the CAD Workspace to show the view above. You can change the view by using the left mouse button click-and-drag to rotate, the right mouse button click-and-drag to pan, and the middle mouse button click-and-drag to zoom. Alternatively, the Pan ( ), Zoom ( ), Rotate ( ), and View All ( ) view modes can be used to orient the CAD assembly. Press Esc to exit any of these view modes and return to select mode ( ).
See Panning, Zooming, Rotating, Viewing the Entire Model, and Focus on Selected for more information on these view controls.
Tip: Press S to save the current view. Now at any time you can restore this saved view of the model by pressing R.
The grouping of parts (that is, creating groups) merges parts into a single body when importing them into MapleSim. You will create groups from the parts in the assembly.
In the Tree View on the left of the CAD Toolbox window, Ctrl-click on frame and the four bushing bolt subassembly groups.
Right-click on frame and then select Create Group. Alternatively, you can click Create Group ( ) in the toolbar.
Enter Base in the Name field.
Click Ok.
The Tree View updates to include the new Base group. Base has five children, frame and four bushing bolt subassembly.
Drag gear motor onto the Base group.
The Tree View should resemble the following figure. Notice that gear motor is now part of the Base group.
6. Create a group named Link using Create Group ( ) in the toolbar and replicate the Tree View shown in the figure.
Tips:
You can add a part to a group by dragging the part onto the group in the Tree View. Similarly, you can move a part out of a group by either dragging it onto another group or dragging it out to the main assembly (which in this example is PickAndPlace).
Each part has properties such as material (density), color, and translucency that you can set. To set the properties for a part, select the part and click Properties ( ) or press P. For more information on part properties, see Setting Part Properties.
This section covers how to prepare parts and groups so that they can be converted to CAD subsystems for use in MapleSim.
You will prepare the parts by adding local coordinate systems (Coords) to them. When the parts are converted to CAD subsystems, the Coords are converted to Multibody ports (or, simply, ports). Ports are needed in order to connect your CAD subsystems to other modeling components.
In particular, this section demonstrates how to add a reference Coord. Reference Coords are necessary when you have to connect two CAD subsystems to the same component. Reference Coords ensure that the geometry of your CAD assembly is preserved and that your model simulates accurately.
Ports can be added during import in the CAD Toolbox window (current window) or after the parts have been imported into MapleSim in the Feature Detect window (for individual parts). This section shows you how to add matched ports in the CAD Toolbox window. The following section demonstrates how to add matched ports in the Feature Detect window.
To prepare your parts and import them into MapleSim:
Right-click on the top slide part and clear the Show check box to hide the part. This will make it easier to place the Coord.
Click Coord ( ).
Place your pointer on the inner round edge of flange bushing and click to place the Coord. This Coord will be used to model rotational motion in the system.
The pointer changes to indicate coordinate placement mode: . When you hover over an edge, the pointer changes to indicate coordinate placement on an edge: . You will know when the pointer is over the round edge when the Coord appears at the center of the circular feature.
Tip: The size of the Coord can be increased/decreased at any time by using the +/- keys on the numeric keypad.
Hover over the inner edge of the flange bushing.
The coordinate is now in place.
Press Esc to exit Coord mode.
Tip: Press and hold the C key to enter Coord placement mode as quick alternative to clicking the Coord button. (Shift + C for placement on a surface) This method is recommended because you exit the mode as soon as you release the C key, and do not have to remember to exit the mode using Esc.
Click the Toggle Coordinates Tree View button ( ) to display only the Coords that have been placed on the CAD model. Expand Base. (The name of your Coord may be slightly different.)
Select the Coord in the Coordinate Tree View and then click Properties ( ). Tip: You also use shortcut keys: press Ctrl + R to rename an object or press P when the part or Coord is selected to open the Properties dialog. For more shortcut keys, see Keyboard and Mouse Shortcuts.
Enter A in the Name field. Close the Properties window. The coordinate is renamed.
Click Place Reference Coordinate ( ). The Add Reference Coordinates dialog opens.
Select top slide as the Target Component.
Click Add and then click Done.
An exact copy of the Coord is attached to top slide. The reference Coord will always have the same position and orientation as the A Coord on the Base group.
Above the Tree View, click to Toggle back to the full Tree View.
Right-click on white space in the CAD visualization window and select Show All. Recall, we'd hidden a part earlier (step 1 of this section), so we now need to show all the CAD components.
Right-click on the pick up plate - Fillet3 part (in the Tree View it is under the suction plate assembly) and clear the Show check box to hide the part. This will make it easier to place the Coord.
Press and hold C and place your pointer on the inner round edge of top slide - Fillet2 and click to place the Coord. This Coord will be used to model translational motion in the system.
Note that you do not need to press Esc to exit Coord mode if you use the keyboard shortcut to place the Coord.
Click the Toggle Coordinates Tree View button ( ) and expand top slide. (The name of your Coord may be slightly different.)
Open the Properties window for the Coord and enter B in the Name field.
Click Place Reference Coordinate ( ) and place a reference coordinate with source coordinate B and target component suction plate assembly. Click Add and then Done.
Right-click in the Tree View or Workspace and select Show All.
Add a Coord to pick up plate - Fillet3 in the suction plate assembly group. Rename it C. In its properties dialog, click on Coordinate and change the orientation to match the following:
In a similar way, add the following Coords to the CAD model.
Coord D on flange bushing - CirPattern1 in the bushing bolt subassembly subgroup in the Base group (bushing at bottom of frame).
Coord E on 12in link in the Link group.
Coord F on link 1 Z.
Coord G on motor crank arm - Fillet1.
Add reference Coords ( ) to replicate the Coordinate Tree View shown in the figure.
Right-click in the Tree View or Workspace and select Show All to ensure the entire CAD assembly is visible. Then press R to restore the saved view.
Next we will import this CAD assembly into MapleSim.
Tip: The current camera angle will be used to create the icons for the CAD subsystems in MapleSim. A good view will make your parts easier to recognize in MapleSim. The current view is also used to select the location of the ports on the CAD subsystem icons. Therefore, a good view will also make finding ports easier.
Click Accept and Return ( ) to finish importing your CAD drawing and convert the parts and groups to CAD subsystems.
A MapleSim dialog box opens with a message telling you where the CAD subsystems are in your Hierarchy.
Click OK.
The parts and groups from your CAD drawing have been converted to CAD subsystems and imported into MapleSim. The CAD subsystems can be found under the Local Components tab ( ), in the Hierarchy palette, in the PickAndPlace subgroup.
Notice that there is one CAD subsystem for each of the top-level groups that were in the CAD Toolbox window. There is also a _group PickAndPlace component. The _group PickAndPlace is a shared subsystem that contains all of the CAD subsystems you created.
In this section you will build the pick and place model in MapleSim by connecting the CAD subsystems in the Hierarchy to multibody components. You will also see how to add ports to CAD subsystems using the Feature Detect window.
To build the pick and place:
From the Hierarchy, drag a Base component onto the Model Workspace.
Drag a top slide component onto the Model Workspace, placing it to the left of the Base component.
In the Model Workspace the CAD subsystems are named Base1 and top slide1, respectively. Notice that both components have a CAD subsystem icon ( ) in their lower left-hand corners. This icon is attached to all CAD subsystems in the Model workspace.
Tip: If you do not see the CAD subsystem icon, from the View menu, select Show Subsystem Markers.
Click Show 3-D Workspace ( ) in the MapleSim toolbar.
The Base and top slide components are drawn in the 3-D Workspace in the correct positions and orientations. If you have show implicit geometry ( ) and axis visibility ( ) selected, you will see the multibody ports (axes), Rigid Body Frames (cylinders), and Rigid Bodies (spheres) that make up the Base and top slide CAD subsystems. Specifically, you should see the following features:
The A port and reference port.
The B port.
The D port.
The G port.
A Rigid Body Frame connecting A to the center of mass (CoM) of Base.
A Rigid Body Frame connecting D to the CoM of Base.
A Rigid Body Frame connecting G to the CoM of Base.
A Rigid Body Frame connecting A to the CoM of top slide.
A Rigid Body Frame connecting B to the CoM of top slide.
A Rigid Body at the CoM of Base.
A Rigid Body at the CoM of top slide.
Tip: Click Show/hide implicit geometry ( ) to hide the multibody components.
Show the port labels on the components by doing the following:
In the Model Workspace, right-click on the Base1 component, and then select Show Port Labels.
Right-click on the top slide1 component, and then select Show Port Labels.
The port names are shown next to the ports. This makes it easier to identify ports when you make connections. Notice that the port names are the same as the names you gave the Coords.
Click Always-On-Top ( ).
The Always-On-Top setting keeps the 3-D Workspace in focus even when you are working in another MapleSim window. This is useful when you want to work in the Model Workspace and at the same time see your model being assembled in the 3-D Workspace.
Click on one of the CAD subsystem ports.
The port becomes highlighted and the axis for the port is highlighted in the 3-D Workspace. Press Esc to delete the connection line from the port.
In the Library Components tab ( ), expand the Multibody > Joints and Motions menu, and then drag a Revolute joint between the components.
Make the following connections between Base1, R1, and top slide1.
Note: The axis of rotation with respect to the Coords is the Z-axis (the blue arrow). The Revolute joint is set to allow movement about the Z-axis by default, so you do not need to make any setting changes for this connection.
In the Local Components tab ( ), expand the Hierarchy > Hierarchy > PickAndPlace menu, and then drag a suction plate assembly component to the left of top slide1.
Right-click on suction plate assembly1 and then select Flip Horizontal.
Right-click on suction plate assembly1 and then select Show Port Labels.
In the Library Components tab ( ), expand the Multibody > Joints and Motions menu, and then drag a Prismatic joint between the components.
Make the following connections between suction plate assembly1, P1, and top slide1.
Note: The figure from step 7 shows that the sliding axis between the top slide and suction plate assembly is the Z-axis (the blue arrow). The Prismatic joint is set to allow movement in the X-axis by default, so the translation axis setting needs to be changed for this connection.
Select the Prismatic joint and set the parameter e1 to [0, 0, 1].
Drag a Link, link 1 Z, and motor crank arm CAD components and five Revolute joints to the canvas. Connect the model as shown in the figure. Use the Flip Horizontal option to flip components as needed.
All the rotations in the model are about the Z-axis, which is the default for Revolute joints, so you do not need to make any setting changes for the connections.
Note: The orientation of R5 has frame_b of the Revolute connected to the CAD component that will be actuated (the motor rotation).
Double-click on Base1.
The Feature Detect window opens with the Base in the CAD Workspace. You will now add a Coord to this part so that you can connect it to a Fixed Frame.
Press and hold Shift + C and place a Coord on the surface of frame - Chamfer1.
Name the Coord Ground and set the positions and orientations to 0 using the Properties window.
The orientation of the Coord determines how the part is oriented in MapleSim. Setting the positions and orientations to 0 means the Coord aligns itself with the Orientation Indicator.
Note: Reference Coords can also be added in the Feature Detect window. In this case the Target Component will be the CAD part that has been opened in the Feature Detect.
Click Accept and Return ( ), and then click OK.
Note that the Base component in the Hierarchy and on the Model Workspace have the Ground port added to them. This is because CAD subsystems are actually shared subsystems. Changes that you make to one instance of a CAD subsystem are made to all instances, including its definition.
In the Library Components tab ( ), expand the Multibody > Bodies and Frames menu, and then drag a Fixed Frame component to the right of Base1.
Right-click on the Fixed Frame component and select Rotate Counterclockwise.
Connect the Fixed Fame component to the Ground port on Base1.
Before simulating the pick and place, a Constant Speed component will be added that will drive the motor crank arm during its simulation.
Select the Library Components tab ( ).
Expand the 1-D Mechanical > Rotational > Motion Drivers menu, and then drag a Constant Speed component above the motor crank arm1 component.
Connect the flange from the Constant Speed component to flange_b on R5.
The following figure shows the complete model with all the appropriate connections.
Click Run Simulation ( ).
After the simulation completes, the simulation results are available in the Simulation Results tab ( ) in the Analysis window. Press Play ( ) to play a 3-D animation of the pick and place model in the 3-D Playback Window.
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