Magnetic actuators

• Published in: Sensors and actuators. A. Physical. Vol. 81; no. 1; pp. 268 - 274
• Main Author: Howe, D.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01.04.2000; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Controlled motion; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Linear rotary motion; Magnetic actuator; Magnetic components, instruments and techniques; Magnetic properties and materials; Permanent magnet; Permanent magnets; Physics; Studies of specific magnetic materials; Linear rotary motion; Controlled motion; Magnetic actuator; Permanent magnet; Linear systems; Actuators; Degrees of freedom; Magnetic devices; Permanent magnets; Magnetic materials; Control method; Experimental study; Motion control; Rotation
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(99)00174-0

The subject of magnetic actuators is very broad, and encompasses various technologies, as well as a wide range of magnetic circuit topologies and performance characteristics, for an ever-increasing spectrum of applications in all market sectors. Magnetic actuators can be rotary or linear, and can have continuous or limited motion, the basic classes being moving-coil, moving-iron and moving-magnet. Within these, the airgap length may either remain constant or vary with displacement, and while the majority of such actuators have only one degree-of-freedom, systems are emerging which are capable of providing multiple degrees-of-freedom of controlled motion. In view of the breadth of the subject, the paper focuses on research which is being undertaken in the Electrical Machines and Drives Group at the University of Sheffield on some specific magnetic actuation systems. These include: • Aerospace—electromechanical and electro-hydraulic actuators for flight control surfaces, • Automotive—short-stroke actuators, for applications such as high-speed diesel fuel injector control valves; active and passive magnetic bearing actuation systems for electric vehicle flywheel energy storage units, • Industrial—long stroke linear motors for high-speed packaging and manufacturing applications, • Healthcare—reciprocating linear actuators for resonant electro-mechanical systems, such as positive-displacement diaphragm air-compressors, • Computer—multi-degree-of-freedom spherical actuators for force-feedback joysticks, manipulators etc. As will be highlighted, much of the research involves the application of high-energy rare-earth permanent magnets, which have facilitated the development of new and improved performance magnetic actuators.