Electromagnetic actuation systems-design and applications

The subject of limited motion electromagnetic actuation systems is now very broad. It encompasses various enabling technologies and a wide range of magnetic circuit topologies, for an ever-increasing spectrum of applications spanning all market sectors. Thus, operational requirements vary widely, in terms of displacement, speed of response, positional accuracy, duty cycle and bandwidth. Further, whilst the majority of actuators have only a single degree-of-freedom, actuation systems are emerging which can provide multiple degrees-of-freedom of controlled motion. As a consequence, it is difficult to give a general overview of the current status of electromagnetic actuation systems. Therefore, the presentation focuses mainly on systems which have been the subject of research at the University of Sheffield, some of which have only been feasible because of the emergence of high energy permanent magnets. The following actuators are discussed: long-stroke and short-stroke actuators; solenoid actuators; active magnetic bearings; reciprocating actuators; and reciprocating generators.