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The main purpose of the paper is to develop model basing on the modified and properly‐adopted Fermi‐Dirac equation which combines proper accuracy with adequate simplicity as well as to show how steady state and transient curves resulting from this model can be applied for solving design task.

The standard Fermi‐Dirac equation was modified and extended. Full performance cycle for the SMA actuator was characterized by double‐valued function describing the actuator activation and the actuator deactivation. All these functions and parameters can be easily determined by analysis of measurement data or with use of Hooke‐Jeeves optimization algorithm.

SMA linear actuator can be used in mechatronic systems as a special non‐standard drive when ultra‐light mass and very simple mechanical construction of power feed system is required. The proposed steady‐state and transient performance curves as well as operation diagram constitute sufficient base for effective designing SMA drive systems.

The greatest disadvantage of a SMA actuator is long time of deactivation resulting from slow self‐cooling process. As far as efficiency is concerned as essential factor for choosing the most suitable linear actuator, there is no sense to take into account a linear SMA actuator because of its very low efficiency.

Designer can use performance curve which determines proper length of SMA actuator and range of its motion. The proposed model can be implemented in SMA drive control unit for controlling position of the actuator.

Similarities between change of martensitic phase during transition process and probability P of electron energy level distribution described by the Fermi‐Dirac two‐variable equation were taken into account. Such an approach seems to express in the most suitable way the physical nature of m‐a transition. The authors decided to extend concept (proposed in Jayender et al.) and to adopt the Fermi‐Dirac equation for describing behaviour of a SMA linear actuator.

The purpose of this paper is to present a new concept of a multi-module electromagnetic launcher with pneumatic assist. The authors focus on the problem of modelling a two-module electromagnetic launcher consisting of a coil-gun (module C) and a rail-gun (module R), as well as on the key problem of determining their position-dependent parameters, i.e. the resistances and inductances of discharging electrical circuits connected with the both modules. Special attention is paid to the possibility of influencing the missile’s flight via basic controller variation of the initial voltage values across the terminals of the capacitor batteries supplying current to both modules C and R.

Analysis of the electromagnetic launcher has been based on the circuit-field approach. Differential equations describing movement of the missile have been drawn from circuit theory. The Finite Element Method and the Comsol Multiphysic program were used to determine position-dependent parameters in module C. It is worth emphasising that the effect of saturation (resulting from B-H curve for ferromagnetic part of the considered magnetic circuit) was taken into account. The influence of the initial missile speed adjusted in a pneumatic assist unit on the missile’s velocity was also considered and illustrated by appropriate simulations (the Matlab program).

In analysing the flight of a missile along coil-gun and rail-gun modules, it is necessary to distinguish between three specific stages of the moveable element: the “fall in” stage, the “drive through” stage and the “fall out” stage. One of the most important findings is that during modelling, it is necessary to take into account of all the three above-mentioned stages of missile movement and, in particular, the “fall in” stage. It was shown both by computer simulations and laboratory investigations that this stage plays an important role in determining the time curves of decaying currents in discharging electrical circuits of both module C and module R.

The main difficulties are related to determining the influence of air drag force upon missile movement (especially in module C), as well as identifying an accurate value for contact resistances and friction force between the rails and the missile in module R.

Hybrid construction employing propelling units of different characters should be treated as a promising and challenging trend in developing launcher structure. One of the most significant advantages of such a solution is the possibility of influencing missile velocity during its flight.

Since the first device was successfully completed in 1920 the continuous rise in the interest on electromagnetic launchers has been observed. As far as their social and technical impact is concerned, one of the most promising fields of interest seem to be launchers of satellites, high-pressure compressors, simulators modelling collisions between meteoroids and the surface of the earth and electromagnetic guns on board war ships.

The novel concept in developing the construction of launchers presented in this paper has been to integrate propelling modules of different characteristics and to create a new multi-module constructional-compact whole. The designed and constructed prototype consists of three modules: a pneumatic drive unit and two electromagnetic drive units that have different principles of operation. The original methodology leading to the creation of its effective mathematical model (focusing on determination of position-depended parameters) was presented and verified in an experimental way.

Aims to present a new approach for formulating state‐space equations of an electromechanical actuator using magnetic flux linkages as state variables.

The model is based on employment of discrete databases and their interpolation. The algorithm of determination of databases defining the flux/current characteristics of an actuator is described. Graphical interpretation of variable transformation is presented. A simplified, two‐axis model of reluctance motor is used to illustrate the application of the proposed modelling technique. Comparison with the classical model of the motor is used to verify the validity of the method. Analysis is focused on determination of saturation phenomenon influence on formulation methodology and on correctness of obtained results.

A very good agreement is observed between reference dq model and the proposed model. The main problem of the presented method is the existence of undefined entries in databases. Sufficiently dense databases can be used to overcome the problem.

The model is limited to actuators in which eddy currents and hysteresis phenomenon can be neglected. Future research will be concentrated on evaluation of different interpolation strategies of databases used in the model for realistic saturation conditions.

The model can be used as a library block for testing various control strategies for actuators without standard simplifying assumptions (e.g. sinusoidal winding distribution). It can be implemented in any simulational software (e.g. SIMULINK) as its block diagram is simple and no numerical differentiation is necessary in derivation of the model data.

Presents an extension of state‐space model of an actuator based on database discretised description of variables to two or more state variables.

The purpose of this paper is to present a modification of the Park variable transformation for a three‐phase wye‐connected winding without neutral wire. A new physical interpretation of the winding equivalent circuit is proposed.

An equivalent circuit representing reluctance motor stator winding is rearranged to enable easier physical interpretation of obtained voltage equation. The Park transformation and constraints resulting from Kirchhof's laws are then applied to obtain a two‐axis mathematical model of the motor.

A new physical two‐phase interpretation of the voltage equation for a three‐phase wye‐connected winding without neutral wire is proposed. A novel two‐axis transformation is formulated for all variables. Compared to the Park transformation, which is the same for all variables, in the proposed transformation its matrices for currents and voltages/flux linkages are different, yet strongly interconnected.

The proposed transformation is formulated for a specific type of winding connection scheme. Therefore, it is limited in its application.

From the practical point of view, the proposed transformation could be very useful as it applies to the most popular stator winding connection scheme. Its main advantages are fewer number of trigonometric parameters in the matrices and measurability of all currents and voltages present in its voltage equations. It could be of special importance for electric machines with non‐sinusoidal field distribution (e.g. Brushless DC).

The paper presents a new type of variable transformation for three‐phase electric machines with wye‐connected windings without neutral wire. Proposed transformation combines different transformations for currents and voltages/flux linkages.