The mechanism has five parts: a rail, a slider, a crank, a connecting rod and a pivot. You'll model them all in one Part Studio with tools you already know. Then you'll connect them in an Assembly with a slider mate for the straight-line motion and revolute mates at each pivot. Animate the main revolute mate and the whole thing moves.
Why this matters for FTC
FTC robots are full of moving mechanisms: intakes that fold out, arms that swing, linkages that carry motion from a motor to a claw. Animated mates let you check, before cutting any aluminum, that parts don't collide during travel, that an arm clears the frame at every angle, and that a slide reaches where it needs to. Finding a collision in CAD takes minutes. Finding it after you've drilled the parts takes much longer.
A slider mate lets a part move along one straight line, like a drawer. A revolute mate lets it spin around one axis, like a hinge. Combine them and you can model mechanisms that turn spinning into pushing, which is exactly what a robot does with its motors.
The tutorial
- Make a new Onshape document in your training folder.
- Work through the video section by section, building each piece in Onshape before you move on.
- Model all five parts, then assemble and mate them.
- Animate the main revolute mate on a loop and check that the slider moves correctly.
Crank-slider · mates & animation
More FTC design lessons are on the way, building toward modeling our full robot. Check the CAD Training page for new lessons.