Recently, glasses containing rare earth ions have evoked interest due to their potential applications in solid-state laser, display devices, sensors, reflecting windows, waveguides, 3D data storage devices etc. In particular the Sm3+ ions in host glass material exhibit broad emission bands due to 4G5/2 →5HJ (J = 5/2, 7/2, 9/2, 11/2) transitions in any host matrix. In order to obtain optimum emission characteristics for device applications, the characteristic features of host as well as concentration dependent studies of Sm3+ are essential. In this regard, a new series of Samarium doped Zinc Lithium Borate glass were synthesized and their optical properties were investigated.
As it was pointed out at the Davos Forum, in the era of talentism, the company's prosperity will depend on human capital. However, human resources management is associated with the need to counter threats to the entire product lifecycle caused by the human factor. Managing labor risks is associated with the need for an individual assessment of the human resource, which is a very laborious task, requiring digitalization of this projects area. The article presents the developed concept of an assessment system and architecture of the labor risks module for project tasks. A mathematical model for calculating labor risks has been formulated, taking into account many factors of the Project Server corporate environment, external sources of corporate data, such as the electronic passes system and MS Outlook e-mail. Algorithms of the program module's operation to calculate resource and design indicators have been developed, and the general architecture of the system has been built. Logical and physical data models are designed, all information system's objects for calculating resource and design indicators are identified. The software implementation methods, the software platform and the environment for implementing the assigned tasks are described in the paper. The software interface of the VSTO add-in was developed, its functional purpose and software forms to operate and analyze the calculated data on resources and project tasks are described.
Students are taught in undergraduate lectures about dynamic systems, control theory and computer programming. However, in the engineering practice a more diverse skillset is required. In addition to the topics covered in lectures, Model Driven Engineering (MDE) should be introduced to the curriculum. With the help of MDE students can learn to develop controls for dynamic systems, furthermore they learn about signal processing and communication systems, using an efficient and effective method. As a case study, the controlled object that is used in this educational project is an Electronic Throttle Valve (ETV). The ETV is used as a laboratory project, because it can be controlled by a diverse range of controller designs, from simple to complex. During the design phase of a new controller, its functionality and reliability should be tested in all development phases. An appropriate process for testing and applying MIL, SIL, PIL and HIL simulation is the V-cycle. This paper describes the related education methods at Deggendorf Institute of Technology (DIT). As an introduction a short description of related educational activities at DIT in current study plans will be given. Thereafter, the modelling method applied to the ETV will be presented together with the control design by Input-Output-linearization. Comparison of the MIL, SIL, PIL and HIL simulation techniques for identifying potential errors are performed for each test-case. The test result of the hardware implementation on an FPGA board will be discussed in the last section.
Extending the lifetime of the wireless sensor node is a critical issue facing the developing of the wireless sensor networks. One of the solutions is employing the energy harvesting technologies to collect renewable energy from the ambient environment. For indoor Wireless Sensor Network (WSN) applications, the chosen of the energy harvester is based on the requirements of the application and the environment. Our application will be used in offices and hospitals so using a noiseless technology is required. So, the photovoltaic energy is the best solution which matches the requirements. In this paper, we will present the design of the photovoltaic energy harvesting system with mathematical modeling and the results of the real experiments.
The paper is focused on the tram input LC traction filter stabilization by the super capacitor energy storage system. The input LC filter is almost undamped resonant circuit connected on the both sides to the sources of disturbances. On the input side, LC filter is connected by the tram pantograph to the dc-trolley overhead lines. The main disturbances are caused by the dc-trolley voltage drops, other vehicles, pantographs head arcs, etc. On the output side, the LC filter is connected to the traction drive. With the constant torque command, the tram during the voltage drops increase the current flow from the LC filter to hold constant torque and thereby further decrease the LC filter voltage, and vice versa. This could lead to unstable traction drive behavior. The super capacitor storage system, which is commonly used to accumulate energy during tram breaking, can be furthermore used to stabilize LC filter voltage. The paper describes the algorithm of the LC filter stabilization by the super capacitor storage system control.
In this paper a method for controlling and stabilizing an unstable nonlinear system using a NARX neural network is presented. It is difficult to design a common feedback controller or even perform system identification on unstable systems, more even so if these systems are nonlinear. To compensate for nonlinearity a feedforward controller is required. In this paper we present a method of estimating inverse model of the system for the feedforward controller using a NARX artificial neural network in an iterative approach which takes less time than methods commonly used and performs as good. This method is verified and tested on an educational model of magnetic levitation of steel ball. Both static and dynamic forms of the inverse model are presented and evaluated with positive results.
This work deals with thermal design of permanent magnet synchronous motor (PMSM). The designed motor is the in-wheel traction motor for automotive. The motor consist of an external rotor and inner stator with water cooling system. The thermal calculation is based on the simplified lumped parameters thermal model and is verified by the finite element methods FEM. The thermal simulation is made for the machine under various operating conditions of the car.
The paper deals with the solution of the finish-abrasive processing issue (contour grinding) of external helical surface. It is proposed to use a robotic system including an external tool, a multi-axis manipulator with a mounted workpiece. The paper investigates the influence of the workpiece movement trajectory relative to the external tool with respect to the parameters identifying a helical surface. As a solution, we proposed to use the algorithm to be developed for robot program performance. The program is developed on the basis of required surface parameters of quality. The approach enables to achieve effective helical surfaces technologies.
Postural balance and stability is a complex neuromuscular task and it requires coordination among different limbs and body parts. The maintenance of balance in upright stance isn't yet completely comprehended and difficulties because of insufficiency in the postural control are of significant concern. The postural control mechanism combines highly nonlinear musculoskeletal structure together with neural control and tactile system in human body. Searching for a model for a more noteworthy comprehension of human postural control framework, this paper displays another computational model committed to the investigation of human upright stance. In this paper we propose a nonlinear control method in light of feedback linearization to imitate the control activity of central nervous system (CNS) in support of postural balance. We use 4-segments biomechanical model with 3 degrees-of-freedom and with rotation about ankle, knee and hip joints. The output feedback is computed with feedback linearization augmented with LQR. The feedback gains are optimized with physiological relevant optimization based on center of mass (COM) and ground reaction forces (GRF). The active and passive torques involved in postural stabilization are computed from reference trajectories and output feedbacks respectively. These torque profiles settle the motion profiles within human anatomical constraints.
An electro-magnetic damping device, consisting of a pot-core with a permanent magnet in the center with a coil wound on it and a ferromagnetic yoke is analyzed in a simplified, linearised form. Experimental results indicate resonance peak attenuation and shift to a lower frequency in respect to a sole mechanical oscillatory system. The contribution aims to explain the device behavior in an indicative way and present some simulation and experimental results.
The field oriented control algorithms (FOC) of induction motor (IM) drives are generally sensitive to model parameter mismatch. Especially, the proper flux orientation and flux amplitude is influenced by the rotor/stator resistance values. Moreover, the rotor and stator resistances are temperature dependent and thus time-varying variables. The real-time testing of different kinds of FOC algorithms to parameter mismatch robustness is a difficult task. The motor parameters such as resistances, inductances, inertia etc. are not commonly tunable in the laboratory experiments. Furthermore, the IM fluxes are not commonly directly measured. The hardware in the loop (HIL) IM simulators operating real-time could be the right choice to FOC algorithms robustness testing. This paper describes the conventional cascade based FOC, feedback linearization based FOC and novel adaptive FOC algorithm tested on self-developed IM HIL FPGA-based platform. The paper presents both HIL based results and experimental results.
Several animal species like rats or seals explore the surrounding environment with their sensory hairs, the so-called vibrissae. Regarding to natural vibrissa, the functionalities of tactile object sensing to receive information about, e.g., the shape and/or the surface texture are often discussed. But, the usage of natural vibrissae to detect flows is reported as well. The necessary information about the flow are coded in the signals recorded at the base of the vibrissa. Due to the natural paragon, we adapt this behavior in order to show up how the information about flows can be extracted from these observables. This is an important procedure because the detection and determination of information about flow effects become interesting for several reasons. For example, in the case of other sensing tasks and strategies like object contour scanning, flows are considered as (possible) disturbances that have to be known to reconstruct any sensed boundary. Otherwise, the flow itself can be of interest. In a first step, simulations are performed to examine the relations between the observables at the base of the sensor and the applied velocity of a flow. Here, a steady-state uniform flow is assumed. The simulations are validated by experiments.
This article is focused on computational modeling of the temperature increase of the high-speed permanent magnet motor. The main aim is to create the calculation program. The program is based on parametric motor model. The methodology of calculation is the Lumped Parameter Thermal Networks (LPTN). The presented work is more focused on convection heat transfer coefficient. In the end is made the evaluation with FEA model of the same machine created in ANSYS.
The proposed control algorithm is focused on reducing and redistribution of power losses among the transistors and diodes in a dual (open winding load) converter. The proposed method combines a space vector PWM (SVPWM) with a finite control set model predictive control (MPC). The SVPWM is used for preselection of basic voltage vectors which are suitable to create a reference output voltage. It enables to identify available switching combinations of basic vectors which are closest to the reference. The MPC enables using a mathematical model of the converter including calculation of power losses and redistribution of them. Using a proposed cost function, it is possible to redistribute power losses to be closely equal among the converter semiconductor switches. The output voltage vector is then utilizing optimum switching combination which is composed of three optimum switching states only.
This paper presents Nonlinear Auto Regressive Moving Average (NARMA) based stable robust adaptive controller design. Both the plant and the closed-loop controller systems are modelled by the proposed NARMA based input-output models. During online supervised learning for the system identification and the controller design phases, input-output data obtained from the simulated plant are evaluated in suitable parameter regions providing Schur stability for the overall closed-loop system. At the same time, ε-insentive loss function and ℓ 1 norm are used for providing robustness for proposed system identification and adaptive controller parameters. The proposed controller design method is performed on quadrotor model which is an unmanned air vehicle benchmark plant. The performance results are compared against proportional derivative controller.
The design of the quasi-online geometric errors compensation method on CNC machine tool using the Ballbar device is described. Nowadays, control and compensation of CNC machine tools are essential phases of their operation. The control is usually manual; the operator and the measuring apparatus jointly perform the measurement and subsequent machine compensation. The present paper describes the procedure and the experiment designed to assess machine condition under various operating conditions. The principle of performed machine tests is based on circular interpolation in manual regime. Prior to experiments, relevant evaluations are made, and quasi-online compensation is devised. For circularity measurement, the DMU 125 P DuoBlock CNC machining centre was chosen
This paper deals with the possibility of evaluating the frequency of the pressure pulses by measuring the motor current and its evaluation. For some applications where it is not possible, to use pressure pulse evaluation from pressure measurements, this method may be appropriate and relatively simple. The article first describes general procedures for evaluating currents. Motor current signature analysis, instantaneous power signature analysis and park's vector approach was chose as used diagnostics method. Next, the article deals with the description of the experiment and then with its evaluation.
This paper deals with the problem of output feedback tracking control of revolute joined robot manipulators with unmeasurable velocities. The controller consists of three parts: (1) a feedforward term, (2) a fist-order linear dynamic compensator, and (3) a nonlinear proportional-like term. Due to the presence of angular variables, the closed-loop system is shown to have a set of all equilibrium points that corresponds to the zero position in a cylindrical phase space. We provide the result on a semi-global asymptotic stability of a reference trajectory. The usefulness of our controller is demonstrated in a simulation study of a three-link spatial robot manipulator.
The paper compares characteristics of three steel types - one standardized in EN 10106 (M235-35A) and two special steel alloys - Arnon5 and Hiperco 50. The iron core loss characteristics are derived to describe the dependence of loss number on magnetic flux density and frequency. Based on obtained results the application field of each material is discussed.
