119 Copyright Goodheart-Willcox Co., Inc. Overview At one time, all manufacturing operations were manually controlled. Gas-fi lled tubes, magnetic contacts, and electrical switchgears served as the primary control devices. Developments in solid-state electron- ics and miniaturization have brought a number of advances in system control. Electromechanical, light, hydraulic, and pneumatic systems are often combined in the control of a single industrial robot. This chapter provides an overview of the types of electromechanical systems used with robots.