Tunable Magnet Actuators: Hysteresis Modelling for Efficient and Accurate Magnetization State Tuning

In this thesis, the accuracy and efficiency of Magnetization State (MS) tuning in Tunable Magnet Actuators (TMAs) is investigated. TMAs are developed to improve thermal stability in quasi-static precision actuation applications. First, the operating principles of TMAs and limitations in previous work are discussed respectively. It is found that the linearization and simplification of magnetic hysteresis limit the accuracy and efficiency of the tuning process. Subsequently, a history dependent tuning algorithm and a generalized non-linear hysteresis modelling methodology are proposed. The tuning algorithm minimizes the energy loss by adhering to the hysteresis properties described by Madelung’s rules. The hysteresis model uses measurement data to accurately calculate the applied field Corner Point (CP). Finally, the tuning algorithm and hysteresis model are experimentally validated for MS tuning of an AlNiCo-5 Permanent Magnet with an RMSE of 5.8 mT and theoretical tuning energies are reduced by as much as 86%.Mechanical Engineering | Mechatronic System Design (MSD