Unit 4: Structure, Materials, and Stability

Robots fail in boring ways. A bracket flexes. A bearing is misaligned. A fastener loosens. The center of mass moves farther than expected. Suddenly the "software problem" is a structure problem.

What must stay true while the robot moves?

Why Robot Frames Flex connects stiffness to sensor and mechanism alignment. Fasteners, Bearings, and Alignment examines joints and rotating support. Mass, Center of Mass, and Stability looks at what happens when the whole robot accelerates, turns, or reaches outward.

The important shift is from asking whether a frame is "strong" to asking whether it preserves the geometry the rest of the system depends on.

Inspect load paths, not just parts

Your Unit evidence is a structural review marking load paths, joints, alignment risks, and center of mass.

Mark where force enters, where it travels, and what supports it. Then identify one location where a small displacement could create a much larger system error.

Vocabulary that earns its place here: stiffness, load path, fastener, bearing, tolerance, alignment, center of mass, stability.

Physical work stays bounded

A static sketch, CAD model, supplied photo, or simulation is enough for the core analysis. Any real mechanical adjustment happens de-energized and under the local workspace rules. "I was only tightening one thing" is not an exception to stored-energy or motion hazards.