Theoretical and experimental investigations of the temperature and thermal deformation of a giant magnetostrictive actuator

Giant magnetostrictive actuators (GMAs) have received considerable attention in recent years and are becoming increasingly important in the exploitation of new type electromechanical devices. The performance of giant magnetostrictive actuator (GMA) is generally determined by the precision of the GMA output displacement; however, the heat-induced displacement of a GMA is the principal element influencing the precision of the GMA output displacement. In this paper, a precise GMA with a heat-induced displacement suppression system is developed; the heat-induced displacement control mechanism consists of a temperature control module and a thermal displacement compensation module. Based on the heat-transfer rules, a GMA heat-transfer mathematical model and a GMM rod heat-induced displacement model are built; next, the mathematical models of GMA heat-transfer are solved and the temperature distribution, the heat-induced displacement, and the heat transfer rate of GMA are completely obtained. Finally, a test system for a GMA heat-induced displacement suppression system is implemented, and an experimental study of the system is performed. The results of the GMA heat-induced displacement by experimental research basically coincide with the results of the GMA heat-transfer mathematical model, that is, the GMA temperatures are controlled to below 35 °C and the GMA heat-induced displacement remains within a small range under an input current of 1 A for a period of continuous operation of 80 min. The system observably improved the precision of the GMA output displacement; as a result, the research results provided a basis for a precise micro-displacement GMA.

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