Define Caster

A caster (sometimes spelled castor) is a single, double or compound wheel mounted on an object in order to make movement easier. Casters can commonly be found on office chairs, dollies, and grocery store shopping carts.

Specific Definition

According to Roland Siegwart and Illah Nournakhsh, authors of "Introduction to Autonomous Mobile Robots" (MIT Press, Cambridge, MA , 2004), a caster is defined as "a wheel mounted to a fork with an additional offset steering joint. The steering joint allows the wheel to rotate freely in a full 360° motion."

Benefits

Casters allow for the easy turning of an object without changing the direction of the chassis that the caster is actually mounted to. Additionally, the angle and distance of the wheel axles and steering joint can be adjusted for different types of caster performance.

Materials Casters Are Made From

Casters are made from a wide variety of materials, including nylon, plastic, rubber, stainless steel, or aluminum, and they often are most effective on smoother surfaces.

Disadvantages

Casters suffer from a phenomenon called "flutter," where the caster will rapidly swing from side to side. This occurs naturally at faster speeds. This can cause an object to suddenly move in an unwanted direction.

Industrial Uses

Heavy duty casters are commonly used on platform trucks and tow lines in industrial plants.

References

• Siegwart, R. and Nournakhsh, I. "Introduction to Autonomous Mobile Robots", MIT Press, Cambridge, MA , 2004.