Electric motors that convert electrical energy into motion are one of the basic components of automation systems. In these systems, either linear or circular motion is needed. Linear motion can be obtained either from motors that generate circular motion with the help of ancillary equipment or directly by the means of a linear motor. Obtaining linear motion from motors that produce rotary motion leads to additional costs and reduced efficiency. Linear motors, on the other hand, eliminate the need for conversion mechanisms. Despite this advantage, linear motors have some disadvantages, such as length limitation and low force/current ratio. In this study, a novel Cylindrical Direct Current Linear Motor (CDCLM) with high force/current ratio and no length limitation (long stroke) has been developed. Analyses of the developed motor has been performed with an analytical method. In addition, detailed numerical analyses have been carried out in an Ansys-Maxwell environment. A prototype of the designed DC linear motor has been implemented in a laboratory environment and experimental analyses have been carried out. The results of analytical, numerical and experimental analyses have been compared.

A linear induction launcher (LIL) is an air-cored coilgun. Its barrel consists of an array of cylindrical drive coils and the barrel can be a single section or divided into several sections. A single-section barrel can be easily driven by energizing the coils in a polyphase fashion to accelerate the moving part of the LIL, the projectile. A multisection barrel, on the other hand, offers higher muzzle velocities for the projectile. From breech to muzzle, each section is energized with an increasing frequency. However, several problems arise when a multisection barrel is used. Some of them are currently reported in the literature. For example, a retarding force on the projectile has been observed while the projectile passes from one section to another. The initial position of the projectile also affects the launching performance. Some experiments can be useful to determine the optimum conditions to reach maximum possible muzzle velocity. This article concerns the design, implementation, and experimental test of a laboratory-scale, two-section LIL to examine the effects of various parameters on the launching performance.

Nonlinear control is generally considered as more complex than linear control techniques by graduate students. This is especially because the analysis and design tools for linear systems comprise mature, simple and powerful methods and so almost all undergraduate programs in system engineering provide some linear control classes. But, on the other hand, all physical systems available in nature are inherently nonlinear. Graduate-level education programs in electrical engineering should provide some courses to the learner to make them able to design and implement more realistic high performance controllers to control the engineering systems. This paper deals with the experimental demonstration of the necessity of having a real-time nonlinear control system to be able to design such controllers. Specifically, the paper is designed as a supplementary experimental tool for a nonlinear control class to boost students’ interest and encouragement in this topic. For this aim, a simple tool, a single-link robot driven by a permanent magnet direct current motor, is used to demonstrate the benefits with the real-time nonlinear control systems and to provide replication facility to an instructor. The paper explains in detail the design and implementation of a nonlinear exact-model controller assuming all the system parameters are exactly known, and then, a more realistic case, a nonlinear adaptive controller with full parameter uncertainty. An additional experiment on the effects of a non-real-time system is also presented.

Tokamak is a fusion reactor that provides extremely high temperature needed for fusion process. Such a temperature is created by confining plasma via some poloidal coils. Control of voltages to be applied to the poloidal coils is an important control problem for proper operation of the overall system. This paper deals with the nonlinear robust control of plasma current, shape, and position in a Tokamak reactor. The paper briefly discusses the modeling issue of a Tokamak, and then, based on a nonlinear state-space model, presents three different versions of a robust controller for the process. All parameters of the system are assumed to be unknown for all three types of the controllers. Lyapunov-type arguments are used to prove the stability of the proposed control schemes. Advantages and disadvantages with each type of controllers are discussed in detail.

Background/Objectives: Mood disorders are described by marked disruptions in emotions. Generally speaking, mood disorders are classified into two main categories: unipolar mood disorder, also known as unipolar depression, and bipolar mood disorder, also called manic-depressive illness. It is estimated that 40 million people live with bipolar disorder worldwide. Mathematical modeling of the dynamics of bipolar disorder may help to both better understand and treat the illness. This is especially important for bipolar disorder since, unlike unipolar disorder, there is an oscillation to be quenched between hypomanic and depressive episodes. Methods: By using a nonlinear dynamical model of bipolar disorder, this study offers two different control (treatment) approaches for the disorder. The first one is a nonlinear exact model knowledge controller assuming that all the parameters of the patient model are known. The second one is a nonlinear adaptive controller assuming that all the parameters are unknown. Results: Both controllers aim to drive both emotional mood and the change rate to a stable state. The Backstepping Technique is utilized as a nonlinear controller design tool. For both controllers, Lyapunov-type arguments are used to design the controller and to prove the stability of the designed controllers. Numerical simulation results are also provided to show the performance and feasibility of the proposed controllers. Conclusions: It has been shown that a nonlinear controller is capable of driving the emotional mood to its equilibrium point, zero, by quenching the mood swing.