The design of a standard robot arm is, more or less, a mechanized representation of an idealized human arm, replete with elbow and wrist joints. Such designs tend to be unwieldy in confined spaces, and unsuitable for many industrial production line processes. As a result, delta arms – a series of interconnected parallelograms which restrict movement to the X, Y or Z directions and do not rotate – have become popular for use in tight workspaces. But, when faced with a requirement for both flexibility and compactness, a design that incorporates the best of both types is required. That's where the double-delta robot comes in.