Swerve Module
Insert a COTS swerve module, position it with joints, and mount it to the frame
What Is A Swerve Module
Each corner can drive AND steer independently
- Two motors per module: drive + steer
- Lets the robot translate and rotate at once
- Four modules = one swerve drivetrain
Open with the big picture. A swerve module is a self-contained corner: one motor spins the wheel (drive), a second motor rotates the whole pod (steer/azimuth). Four of them give you full omnidirectional movement. Stress that we are NOT designing the module from scratch today. These are COTS (commercial off the shelf) units. Our job as CAD designers is to place a known-good part correctly and build the robot AROUND it.
Maxswerve Vs Mk4I
Both are proven COTS modules used by top teams
- REV MAXSwerve: compact, NEO/Vortex, cheaper
- SDS MK4i: inverted steer, NEO or Kraken
- Today we use MAXSwerve as the example
- Download the vendor STEP before class
Briefly compare. MAXSwerve mounts to the TOP of the frame rail with a bolt pattern; MK4i hangs the steer motor up top so the module sits lower. Either is fine for our learning goal. Tell students to grab the official STEP file from REV (revrobotics.com) or SDS (swervedrivespecialties.com) ahead of time so we are not all hammering the download mid-class. We import STEP, not Onshape's MKCad library.
Download The Step File
COTS parts come from the vendor, not modeled by you
- Find the module's CAD/Downloads page
- Grab STEP (.step/.stp) or F3D if offered
- Save to a known folder on your machine
- STEP carries geometry; no editable history
Explain file formats. STEP is the universal CAD exchange format. It brings in solid bodies but NO feature history, so you cannot edit how it was built. That is fine for COTS. If a vendor offers a native Fusion .f3d, even better. Common mistake: students grab a STL (mesh) by accident. STL is for 3D printing, it imports as a blobby mesh, not clean solids. We want STEP.
Insert > Insert Mcmaster Or Upload
Insert > Insert into Current Design for STEP
- Or upload STEP to your Data Panel first
- It lands as a Component with bodies
- Use Insert McMaster-Carr for hardware
- Rename the component immediately
Demo the actual insert. Two paths: (1) upload the STEP to the Data Panel, then drag it in, or (2) Insert > Insert into Current Design. The module arrives as its own Component. CRITICAL FRC habit: rename it right away in the browser, e.g. MAXSwerve_FL. Unnamed Component1, Component2 chaos is the number one thing that wrecks a real robot assembly. Mention Insert McMaster-Carr pulls bolts and bearings directly with correct part numbers.
GROUND THE FRAME FIRST
One component must be fixed in space — usually the drivetrain frame — so everything else has something to attach to.
Joints = Onshape Mates
A Joint defines how two parts connect and move
- Rigid: bolted solid, zero motion
- Revolute: one rotation axis (the wheel)
- Slider: one straight axis of travel
- ASSEMBLE > Joint, pick two faces/edges
Translate the vocabulary. If they know Onshape, Joints ARE Mates. For mounting the whole module to the frame we want RIGID, it is bolted and does not move relative to the chassis. Revolute is for the spinning wheel and the steering axis. Slider is for things like an elevator carriage, not used here. Show the two-click workflow: pick a point/face on the module, then the matching one on the frame.
Rigid-Joint To The Frame
Use Rigid Joint to bolt the module to the rail
- Snap module's mount face to the frame top
- Align to the real bolt-hole pattern
- Check it sits flush, not floating
- Capture Position if it jumps
Live demo the real mount. Select the module's mounting-plate hole as Joint origin 1, then the frame rail's corresponding hole as origin 2, motion type Rigid. The module should snap flush onto the top of the tube. MAXSwerve uses a specific hole pattern on 2x1 tube. Common mistake: the part flips upside-down or 90 degrees off, use the Flip / Angle / Offset options in the joint dialog to correct orientation. If the body teleports weirdly, right-click > Capture Position.
Pattern The Corners
A drivetrain needs a module at each corner
- Insert again or copy the component
- Rigid-joint each to its own corner
- Name them FL, FR, BL, BR
- Keep steer zero pointed consistently
Now scale up. You can Insert the STEP four times, or copy-paste the component (each instance shares geometry, lighter file). Joint each one to its corner. Naming convention matters on a real team: Front-Left, Front-Right, Back-Left, Back-Right. Note that diagonally opposite modules are often mirror images on MK4i; MAXSwerve is symmetric so identical copies work. Make sure every module's 'forward' is consistent or your steering offsets will fight you in code later.
COTS PARTS ARE REFERENCE, NOT CLAY
Never edit an inserted module's internal geometry — design your robot to fit it, and let it stay a clean, swappable block.
Your Task
- Sketch a square frame from 2x1 tube
- Ground the frame component
- Insert a MAXSwerve STEP file
- Rigid-joint a module to all 4 corners
- Name modules FL, FR, BL, BR
- Verify all modules sit flush
- Fusion > Share > Public Link
- Paste the link on AltHub
This is the graded build. Give them ~30 min. Walk the room watching for: ungrounded frame (everything floats), modules jointed to the wrong face, and unnamed components. A correct submission is a square frame with four flush, correctly-named modules. To submit: top-right Share button > Share Public Link > copy, then paste into the AltHub assignment post. Remind them Share Public Link must be toggled ON or mentors cannot open it.
🧰 Add-ins for this step
Use the installed AltSkripts / FRC-COTS tools here — don't do it the slow way.
- FRC-COTS — search your swerve module (e.g. MAXSwerve), click to insert; it auto-joints to the frame.
You Mounted A Swerve Drive Don'T Remodel Cots Parts
- Insert COTS as STEP, rename it immediately
- Ground the frame, then Rigid-joint modules
- Next: route motors, gears, and wiring around it
Your Task
- Model what this lesson covers in Fusion 360.
- Use the AltSkripts tools where they apply.
- Save it with a clear name.
- In Fusion: Share → Public Link → Copy.
- Paste the link below.
- A coach reviews it in AltHub.