Design and control of linear actuators made by magnetically controlled shape memory alloy

This paper introduces the basic structure of a magnetically controlled shape memory alloy (MSMA) actuators based on the actuation principle of the NiMnGa alloys under external magnetic field. A new differential control strategy of MSMA actuator was proposed and the differential linear MSMA actuator has been built and tested. The new MSMA actuator has the advantages of smaller excitation power and higher control accuracy. An inchworm type linear MSMA motor has been designed and built. The linear motor adopts the economic way to get the large displacement by using a small piece of MSMA material based on the inchworm approach. The feasibility of the new MSMA linear motor design has been proved by the tested result of the prototype machine.