A novel design for a strip-type microthrottle pump with a rectangular actuator geometry is proposed, with more efficient chip surface consumption compared to existing micropumps with circular actuators. Due to the complex structure and operation of the proposed device, determination of detailed structural parameters is essential. Therefore, we developed an advanced, fully coupled 3D electro-fluid-solid mechanics simulation model in COMSOL that includes fluid inertial effects and a hyperelastic model for PDMS and no-slip boundary condition in fluid-wall interface. Numerical simulation resulted in accurate virtual prototyping of the proposed device only after inclusion of all mentioned effects. Here, we provide analysis of device operation at various frequencies which describes the basic pumping effects, role of excitation amplitude and backpressure and provides optimization of critical design parameters such as optimal position and height of the microthrottles. Micropump prototypes were then fabricated and characterized. Measured characteristics proved expected micropump operation, achieving maximal flow-rate 0.43 mL·min⁻¹ and maximal backpressure 12.4 kPa at 300 V excitation. Good agreement between simulation and measurements on fabricated devices confirmed the correctness of the developed simulation model.

The hysteresis of magnetoresistive sensors remains a considerable cause of inaccuracy of positioning applications. The phenomena itself has been well studied and described by different physical and phenomenological models. Various biasing techniques have been proposed. However, the increased fabrication and computational price they require is undesirable. In this paper, a computational algorithm for the compensation of hysteresis of linear and rotary encoders is proposed. A lagging-domain model based on play operators is presented for prediction of hysteresis. The outlined procedure for the calibration of parameters allows the use of the algorithm for various types of encoders without knowing their exact material properties. The method was tested on different anisotropic magnetoresistive and tunneling magnetoresistive sensors. Results show that the impact of hysteresis was reduced by up to 90% without a significant increase of computational time or production costs.

An application of a current sheet as a finite element in the Boundary Element Method (BEM) is described. A detailed procedure for mathematical and software implementation of a Current Sheet Element (CSE) as a Finite Boundary Element (FBE) in BEM analysis is presented. For a simple generic magnetic circuit with a stator and a rotor, the calculated magnetic field and torque values are compared with the values obtained by two different Finite Element Method (FEM) based simulation programs showing a good agreement, however, elucidating the fact that even by employing professional FEM tools, on fairly simple problems, accurate determination of forces and torques is not necessarily guaranteed. Certain aspects of using the Maxwell Stress Tensor (MST) for the determination of forces and torques on the rotor domain are discussed. Since the primary magnetic field sources are currents in a set of conductors of circular cross-section, analytical expressions are used for the calculation of the primary field. Due to the selected geometry of the FBEs, i.e., CSEs, after a numerical determination of their currents by BEM, analytical expressions are employed for the calculation of FBEs fields as well.