Lightweighting (Magnesium Alloy / Carbon Fiber)

Using light materials like magnesium alloy, carbon fiber, and engineering plastics to cut a robot's weight.

Lightweighting means reducing the weight of a robot's structural parts while still meeting strength and stiffness requirements, using materials such as magnesium alloy (about two-thirds the density of aluminum alloy), carbon-fiber composites (high strength per unit weight, good for rods and shells), and engineering plastics such as PEEK. For legged and humanoid robots, the benefits of cutting weight compound: lighter limbs mean lower rotational inertia, which means the joint motors need less torque, which extends battery life and reduces impact force in a fall or a collision with a person. The trade-off is higher material and manufacturing cost — magnesium alloy needs corrosion treatment, and carbon-fiber parts are hard to repair. It's commonly discussed alongside plastic-for-steel substitution, payload-to-weight ratio, and battery life.

ExampleReplacing an aluminum-alloy lower leg with a carbon-fiber tube reduces mass at the far end of the leg, making the hip and knee joints work less hard when swinging the leg quickly.

Also called

Lightweight Design

Related

Replacing Steel with Engineering Plastics (Plastic-for-Steel Substitution) · Payload-to-Weight Ratio · Moment of Inertia · Battery Runtime · Polyether Ether Ketone (PEEK) · Torque Density

Sources

Magnesium alloy - Wikipedia
Carbon-fiber reinforced polymers - Wikipedia