In this work, the generalized finite difference method (GFDM), a popular meshless numerical method, is employed for predicting the thermal and mechanical behavior of an electrothermal micro-actuator. Based on the concept of GFDM and discretization on the computational domain, the discrete forms of the thermal and mechanical governing equations are derived, respectively. With the help of the incremental load method, the discrete form from the electrothermal analysis is solved precisely and the temperature distribution is obtained. Meanwhile, combining this approach with the discrete control equation derived from the natural boundary condition, its displacement is also evaluated. The convergence of the temperature by different iterative methods is tested and compared. The computational stability and efficiency (CPU time) in these two analyses are also given in this study. To further investigate the accuracy of the solutions, experiments to capture temperature and FEM analysis are conducted. Regardless of the imperfect boundary condition, the temperature distribution calculated by the GFDM shows great agreement with that obtained by experiment and FEM. A similar phenomenon can be also found in the comparison between the displacements evaluated by the GFDM and FEM, respectively.

Electrothermally actuated micro-beams are expected to be massively adopted in the micromanipulation and microassembly, due to their easy access to a larger motion. As a case study in this work, an amended electrothermal analytical submodel governing the temperature distribution of the V-shaped actuator is first established. Based on the thermal expansion and elastic equilibrium, a thermo-elastic coupling equation that determines the displacement is then deduced. The Galerkin weak form of these two coupling equations is obtained by the variational principle. So the RPIM, independent of the traditional Lagrange mesh, can be successfully introduced to obtain their solution. The convergence of the solutions both in the electrothermal and the thermo-elastic submodel is validated. The ideal radial basis functions in the RPIM are found to be applied into the different submodels, respectively. To further investigate the accuracy of the solutions, temperature experiment and FEM analysis are conducted. The temperature from this work shows great agreement with that from the experiment. Similar observation is obtained in the comparison between the displacements separately from the RPIM and FEM.

This paper presents a novel implementation of the Polynomial Point Interpolation Collocation Method (PPCM) for analyzing the coupled electrothermal and thermomechanical behavior of V-shaped microactuators. Within the PPCM framework, the governing equations for heat transfer and structural mechanics are discretized over the computational domain. The resulting discrete electrothermal system is solved in a fully coupled manner via an incremental load method to determine the temperature field. Subsequently, the displacement field is computed by solving the discrete mechanical equation, which incorporates terms from the natural boundary conditions. The MQ radial basis function behaves well in convergence when its parameters p_a and p_q are 1 and 1.8. Under a 6 V voltage, the difference between the PPCM and FEM temperature values is less than 1 °C. Meanwhile, the discrepancy between the PPCM and experimental temperature values is approximately 20 °C, corresponding to an approximate error of 10%. Furthermore, the displacement error between the PPCM and FEM is as low as approximately 2 μm under an applied voltage of 12 V. These results validate the PPCM for predicting the driving characteristics of V-shaped microactuators.

As the core power equipment and primary load in power systems, electric motors are involved throughout the entire power generation, transmission, substation, and distribution processes. Their operational reliability directly determines the safety and stability of the power grid. This paper provides a systematic analysis of the current status and future trends in motor fault diagnosis. Specifically, it summarizes the three mainstream approaches currently used in motor fault diagnosis: model-based methods, signal processing-based methods, and artificial intelligence-based methods, while highlighting the respective advantages and application limitations of each approach. The analysis reveals three prominent challenges in existing research: inefficient multi-source information fusion, difficulties in early weak fault detection, and insufficient stability in decision-making integration. Future research directions are identified, including mechanism-data dual-driven strategies, deep cross-dimensional feature fusion of current, vibration and temperature signals, denoising algorithms for faint fault features,and edge-based online diagnostic systems for full-life predictive health management. It clarifies that overcoming the limitations of single-domain analysis, establishing an efficient fusion framework, and enhancing adaptability to complex operating conditions are crucial for further improving diagnostic accuracy and ensuring reliable operation of motors and power supply systems.

This paper presents a case study demonstrating the use of the moving least square method (MLS) for modeling the mechanical response of an electrothermal microactuator. Under the MLS framework, the governing equations for heat transfer and structural mechanics are discretized across the computational domain. The resulting discrete electrothermal system is solved accurately through an incremental load and Newton–Raphson iterative method to determine the temperature field. Subsequently, the displacement field is obtained by solving the discrete mechanical equation, which includes contributions from natural boundary conditions. Convergence of the temperature solution is rigorously evaluated across different iterative schemes. The accuracy of the MLS solutions is validated against experimental temperature data and finite element method (FEM) simulations. Results indicate that the temperature distribution obtained from the MLS aligns well with both experimental and FEM results, even under idealized boundary conditions. Additionally, a similarly favorable comparison is observed between the displacement fields predicted by the MLS, polynomial point interpolation collocation method (PPCM), and FEM.