Motion control in product design

Designers sometimes must choose whether to create a mechanism that will guide the motion of a rigid body or to use a battery of actuators with integrated electronic controls. Usually the actuators win, despite cost and other advantages of simple mechanisms because it is easier to pick readily available motors from a catalog rather than design a new mechanism. The term `mechanisms' used here encompasses conventional devices, from linkages, cams, and gears to intermittent mechanisms. A fundamental tenet of mechanism design is to minimize the number of actuators (the number of kinematic degrees of freedom) required to perform a given task. The challenge lies in designing such mechanisms to obtain intricate motion output, typically with a single actuator.