Design and Performance Analysis of Magnetic Shape Memory Alloy Actuator With a Compact Electromagnetic Coil Configuration

Magnetic shape memory alloy (MSMA), which has emerged in recent years, has been proven to have great potential for electromagnetic actuators due to the long life cycle, fast response, and relatively large load capacity. Current research on such material mainly focuses on the fundamentals, thermal effect, composition, and magnetic induction strain, but issues involved in its application to the industry are rarely addressed in detail. This article first analyzed the principle of magnetically induced strain and the corresponding constitutive equations, and investigated the magnetomechanical characteristics of the MSMA sample through measurement carried out on a specially designed experimental setup. Taking advantage of good drive performance, MSMA electromagnetic actuator with spring recovery was designed in detail. In order to resolve the contradiction between compactness and high magnetic field strength, a novel configuration with double-layered coils was proposed to achieve the required magnetic flux density. Influences of input current, prepressure, and spring stiffness on the dynamic response characteristics of the actuator excited by step signal and square wave signal input were analyzed by simulation. Finally, the experimental platform is built to verify the feasibility of the configuration and dynamic characteristics of the actuator. The experimental results show that the designed actuator has good output performance with a response time of 25 ms, demonstrating the superiority of MSMA in microdisplacement actuator with high dynamics.