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ROVER’S FRAME

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What Does A Rover Robot Have?

  • Computer Brain
  • Body / Frame
  • Motors
  • Sensors
  • Wires
  • Wheels

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What You Will Learn

  • Electronics
  • 2D Design
  • Coding
  • Navigation

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ROVER’S FRAME

using OnShape Engineering CAD

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Robot Frame

  • Support all components
  • Flat 2D board (...easier for first time CAD users)
  • Will be laser cut from plywood (...can also use Acrylic, carbon fibre, Acetal, but plywood is more forgiving of mistakes)

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OnShape

  • Professional engineering CAD (Computer Aided Design) software
  • Capable of 3D design… but we are only doing 2D in this workshop
  • Runs in browser, no installation required
  • Free for non-commercial use

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OnShape Account

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Create a new document

  1. Create
  2. Document

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Create a sketch

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Select sketch plane

Click here to select the “Front” plane as the sketch plane

Press “n” on your keyboard to rotate the view

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Create board

1.Click here to enter rectangle drawing mode

2.Click anywhere on the sketch plane to start drawing

3. Click a second time to complete the rectangle. Don’t worry about the dimensions for now

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Create board

The lines are in blue, indicating that they can still move around; we haven’t locked them in place or set the dimensions (we’ll do that next)

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Lock one corner

1. Press “esc” on your keyboard to exit rectangle drawing mode (...rectangle button is no longer highlighted)

2. Click on these two points to select them

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Lock one corner

3. Click this to set a “coincident” constraint on these two points

There are many other constraints available; open the dropdown to view them

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Black lines

Some of the lines are now in black, indicating that they can no longer be moved.

The top and right lines are still moveable (...try dragging them).

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Set dimensions

1. Click this to enter dimension mode

2. Click this line to select it for dimensioning, then a second click outside the line to confirm it

3. Set the dimension to “195 mm”

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Set dimensions

1. You should still be in dimension mode (button highlighted)

2. Click this line to select it for dimensioning, then a second click outside the line to confirm it

3. Set the dimension to “335 mm”

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Board dimensions

You can change the dimensions and even the shape of your robot frame (...doesn’t have to be rectangular), but DO IT LATER!

At the end of these slides, we will share the design limits. As long as you stay within these limits, you can design your robot frame your way.

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Mounting holes

  • Need to provide mounting holes for components
  • We’ll run through the mounting holes for the motor brackets
  • You’ll need to do the rest on your own

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Engineering drawings

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Engineering drawings

For this component, there are 6 mounting holes, but it’s enough to use just 4.

Size of the holes are 4mm

Distance between holes are 53.6mm and 30mm

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Draw mounting holes

1.Click here to enter circle drawing mode

2. Click once to set the center of the circle, and a second click to set the radius. Don’t worry about the size for now.

Draw 4 circles.

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Set hole size

Exit circle drawing mode (“esc” key), then select the edges of all 4 circles

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Set hole size

1. Open the constraints dropdown

2. Select the “Equal” constraint. This set all the circles to have equal diameters.

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Hole dimensions

1.Click this to enter dimension mode

2.Click on the circumference of one circle and left click somewhere blank

3.Set diameter to 4.2mm (slightly bigger than the 4mm screw for an easier fit)

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Circle alignment

1. Select the center of these two circles

2. Select the “Vertical” constraint.

This forces the two circles to be vertically in line with each other.

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Circle alignment

1. Select the center of these two circles

2. Select the “Horizontal” constraint.

This forces the two circles to be horizontally in line with each other.

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Circle alignment

1. Repeat the horizontal constraints for the bottom two circles

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Circle alignment

1. Repeat the vertical constraints for the two circles on the right

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Alignment with board

2. Click to select the top edge, then the center of a top circle, then click a blank area to set the distance between them (10mm)

1.Enter dimension mode

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Alignment with board part 2

Select the left edge and the center of a left circle to set the distance between them (10mm)

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Distance between holes

In dimensions mode, select the center of the two circles to set the distance between them (30mm)

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Distance between holes

In dimensions mode, select the center of the two circles to set the distance between them (53.6mm)

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Mounting holes

Complete dimensions for front left motor

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Four motors

We showed you this…

…now it’s on you to do the rest.

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Ending sketch

Click the green tick when you are done

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Export sketch

Right click on your sketch…

…then “Export as DXF/DWG”

This example is NOT complete; you’ll need to add mounting holes for all the components first.

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Export sketch

1. Put in your team number

2. Ensure the settings match

3. Click Export

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Upload sketch

  • Open the file sharing page at https://a9i.sg/holiday26
  • When prompted for a name, provide your name
  • Upload your sketch (DXF file)