A frequency‐locked position servo control system by microprocessor‐based slope‐varied technique

Abstract

A microprocessor‐based slope‐varied frequency‐pumped controller (μP‐SVFPC) for improving the locking performance of the frequency‐locked position servo control system (FLPS) is presented. The presented slope‐varied pump technique is to perform the position control process fast for a long distance servo, while nearly similar acquisition times for different distance servos are obtained during the servo range. The motion profiles for system locking are adaptively generated according to the coming frequency error. No motion profiles are required to be pre‐installed in the controller. A prototype of μP‐FLPS is realized, simulated, and tested. Computer simulation and experimental result confirm that the system acquisition times of μP‐FLPS for short, middle, and long distance servos are nearly similar to each other. In comparison with the basic FLPS system, the acquisition times of the presented μP‐FLPS for the middle and long distance servos are improved by about 58% and 85%, respectively.     

Analysis and design of frequency‐controlled oscillator for frequency‐locked stepping position control system

Abstract

A frequency‐locked stepping position servo system (FLSPS) is presented. The proposed microprocessor‐based sloped‐varied frequency‐controlled oscillator (SVFCO) is designed to achieve nearly the same acquisition times for different position commands. The slope‐varied technique is to quickly position for long distance servo during the wide‐range control. The motion profiles for position locking are adaptively built according to the periodically sampled frequency error. No motion profiles are required to be pre‐installed in the controller. The system model is built for stability investigation and simulation. A design example is realized to verify the theoretical predictions. System simulation and experimentation confirm that the system acquisition times for short, middle, and long distance servos are very close to each other. In comparison with the corresponding traditional stepping position system, the acquisition times of the FLSPS are improved by 53% and 73%.     

A microprocessor‐based electrohydraulic servo system

Abstract

A microprocessor‐based electrohydraulic servo system has been constructed and tested. It is implemented with an 8‐bit single‐chip microcomputer to control a hydraulic motor. The control algorithm is based on variable structure control principles. The experimental results show that the system is under good control and possesses a great potential for electrohydraulic servo control.     

A frequency‐dependent droop scheme for parallel control of ups inverters

Abstract

This paper presents a frequency‐dependent droop scheme for paralleling UPS inverters with no control interconnection, so the inverters can be tightly connected with the load. At the fundamental frequency, the reference voltage of the inverter is generated as a reactor connected between the inverter and the load. The intention is to control the real and reactive power sharing of inverters with the Q‐V and P‐ω droop scheme employed in the power system without needing a true transfer reactor. At the harmonic frequency, the reference voltage is generated as a resistor connected between the inverter and the load. The intention is that the load harmonic current can be shared equally and the voltage waveform distortion will be low. Two 1KVA single‐phase inverters are designed and implemented, some simulation and experimental results are provided for demonstrating the effectiveness of the proposed approach.     

A computer‐aided design system for NC part program

Abstract

The electron cyclotron maser is a novel electromagnetic radiation mechanism employed in a new class of microwave devices called the gyrotron. In this expository paper, the electron cyclotron maser interaction is analyzed on the basis of a simple physical model. The purpose of the analysis is to quantitatively elucidate the details of the interaction processes, such as the electron bunching in the cyclotron phase space, the time scale of interest to the interation, the matching condition between the wave and cyclotron frequencies, and the parametric dependence of the electron energy loss rate.     

Application of variable‐structure system in dc‐motor velocity‐control

Abstract

The most important characteristic of variable‐structure system (VSS) is its insensitivity to parameter variations in the sliding mode. In this paper three methods of VSS are used to implement DC‐motor velocity‐control. The conventional VSS uses only a sliding line. The adaptive VSS uses multiple switching lines. The modern method uses a sliding curve. The modern method makes a system trajectory following the sliding curve which has been set up in the controller from the initial state to the origin in the phase plane. Hence it is insensitive to parameter variations from the initial state to the steady state. If parameter variations are the most critical factors, then the modern VSS is the right method to be considered to overcome the problem of parameter variations.     

The design and implementation of an interactive news‐on‐demand system

Abstract

In this paper, we present a news‐on‐demand system that consists of 1) a news database, 2) a news search engine, and 3) a news editor. All multimedia data are stored in the news database. Through the system, readers not only can browse multimedia news in the database, but also can query the relevant news with a specified predicate. Also, to help journalists to edit their electronic news, we also design the news editor. It helps journalists to edit their news homepages, even if they are not experts in HTML programming.     

Design of a double microprocessor‐based on‐line process control system

Abstract

A numerical technique for integrating the full Navier‐Stokes and diffusion equations through an initial value problem has been used to investigate the time development of a line buoyant source issuing in a density‐stratified environment. The basic physical features and some structures of the interactions of the motion at the intermediate mixing region are obtained. Results show that the stratification tends to inhibit the flow development of the buoyant source and to encourage the formation of a recirculatory vortex on the lower region near the source and the upper region.     

Combinatorial growth and analysis of Ti-In-Zn-O films deposited by radio‐frequency and direct-current magnetron co-sputtering system

The compositional dependence of co-sputtered Ti-In-Zn-O film properties was investigated by means of a combinatorial technique. The X-ray diffraction result showed that the amorphous Ti-In-Zn-O films were fabricated regardless of the Ti contents [Ti / (Ti + In + Zn), at.%] of 4.5-34.4 at.%. The surface of amorphous Ti-In-Zn-O film is quite smooth. The obtained surface roughness (R_RMS) values ranged from 0.5 nm to 1.7 nm. The superior resistivity of 3.8 × 10^− 4 Ω cm and the transmittance of 92% (at 550 nm) was obtained for the Ti-In-Zn-O film with the elemental composition ratio of 18.6/68.5/12.9 at.% [Ti/In/Zn, at.%]. The indium quantity actually could be reduced to as high as ~ 15 at.% compared to that of commercial indium tin oxide or indium zinc oxide having similar resistivity value of ~ 10^− 4 Ω cm. Overall, the amorphous Ti-In-Zn-O films may serve as a viable, low-cost alternative for flexible transparent conducting electrode applications.     

Experimental verification of a radar target discrimination technique using multiple‐frequency amplitude returns

Abstract

An experimental study of radar target discrimination using multiple‐frequency scattering amplitude without phase data is presented. Based on the concept of natural resonance frequencies, the technique is aspect‐angle independent so that a priori information of the aspect‐angle is not necessary. The radar cross sections of a spheroid and a thin wire are measured at different aspect ‐ and bistatic‐angles to distinguish different spheroids and wires in the resonance frequency range. The results show that the discrimination algorithm works well and can be applied to both monostatic and bistatic radars.     

A self‐tuning control approach of mechanical manipulators

Abstract

The dynamic model of a manipulator system is a time‐varying highly nonlinear coupling equation set. When the moving speed increases or the payload, compared to its own weight, is no longer small, the performance of the conventional control schemes is not satisfactory for precision industrial application. Here a new adaptive control approach is developed for the manipulators to solve these problems. This algorithm directly uses a nonlinear dynamic model in the controller design to account for the nonlinear effects of the system. The least‐square time‐varying parameter identification scheme has been used to identify the change in configuration and payload. The simulation results show that this new approach has a very good trajectory tracking performance.     

Composition control in Cu2ZnSnS4 thin films by a sol–gel technique without sulfurization

Kesterite Cu₂ZnSnS₄ (CZTS) thin films with a smooth, compact and crack-free morphology are obtained via a sol–gel method without sulfurization process. Non-toxic ethylene glycol is selected as solvent, while Cu(CH₃COO)₂, Zn(CH₃COO)₂, SnCl₂·2H₂O and thiourea are used as raw materials. Chemical composition dependence of CZTS films on pre-annealing and post-annealing process is comprehensively investigated. The analysis of energy dispersive X-ray indicates that composition control of CZTS films can be easily realized by the preparation of precursor solution and varying the annealing conditions.     

A novel design of a cpw‐fed single square‐loop antenna for circular polarization

Abstract

The experimental and simulated results for the proposed antenna are investigated in this article. Moreover, a novel broadband design of a circularly polarized (CP) single square slot antenna fed by a single coplanar waveguide is presented. By appropriately choosing the circumference of the square‐loop, the length of the protruded strip, and the gap, this proposed antenna thus owns good CP radiation and good impedance match simultaneously at the frequency of 2.45 GHz. This proposed antenna has the fundamental resonant frequency of 2.5 GHz with the minimum return loss of ‐39.9 dB. Furthermore, its impedance bandwidth is 460 MHz or 18.4% and 3‐dB axial‐ratio (AR) bandwidth is 360 MHz or 14.4% at 2.5 GHz.     

A study of the feature‐based digital image stabilization system

Abstract

This article presents a digital image stabilization scheme that uses image processing techniques to compensate for undesirable image jitter due to vehicle or platform vibration to obtain a stabilized image display. The developed digital image stabilization system is based on the image combination approach combined with advanced image selection, feature detection, feature matching and pre‐rotation processing to produce crisp images. Using the Sobel edge detector, we calculate the magnitude of edge response as the judgment criteria for image transformation. To demonstrate the validity of the proposed technique, experimental results are given for some synthetic images.     

A discussion on “On the solution of a class of fuzzy system of linear equations”

The paper is a discussion on the results obtained by Salkuyeh in the article (Sādhānā 40(2):369–377, 2015). Salkuyeh considers the solution of the fuzzy system of linear equations (FSLE) and gives numerical examples where the results of FSLE are calculated. It was shown that the results by Salkuyeh are not full solutions and do not satisfy equivalent forms of the analysed FSLE. The paper presents a multidimensional approach to finding the solution of the FSLE. On the basis of the notation of the horizontal fuzzy number, a full solution that satisfies the FSLE and its equivalent forms is obtained.     

Antibacterial activity of silver-loaded zeolite A prepared by a fast microwave-loading method

Silver ion was loaded into zeolite A by a rapid synthesis method, microwave loading, to obtain an antibacterial agent suitable for use in biological applications. Antibacterial activity of silver-loaded zeolite A against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus was determined by minimum inhibitory concentration, revealing its potential as a strong bactericide.     

A formal control-theoretic model of a human–automation interactive manufacturing system control

This paper describes a human–automation interactive manufacturing system and presents a formal model for describing and controlling the system. The model presented in this paper considers a system from two perspectives: structural and operational perspectives. Human and an automated controller are considered agents that cooperate to achieve given goals by executing assigned tasks. A human–automation interaction is described with a particular communication model between two agents that exchanges messages. A system control schema and human tasks are modelled separately and then integrated in a formal manner using a modified communicating finite state machine framework. An interface model that coordinates the message exchanges between two agents is then introduced. An automated shop floor control system with a human material handler is modelled with the proposed framework and a simple illustrative example is provided.     

Who is in control of road safety? A STAMP control structure analysis of the road transport system in Queensland,Australia

Despite significant progress, road trauma continues to represent a global safety issue. In Queensland (Qld), Australia, there is currently a focus on preventing the ‘fatal five’ behaviours underpinning road trauma (drug and drink driving, distraction, seat belt wearing, speeding, and fatigue), along with an emphasis on a shared responsibility for road safety that spans road users, vehicle manufacturers, designers, policy makers etc. The aim of this article is to clarify who shares the responsibility for road safety in Qld and to determine what control measures are enacted to prevent the fatal five behaviours. This is achieved through the presentation of a control structure model that depicts the actors and organisations within the Qld road transport system along with the control and feedback relationships that exist between them. Validated through a Delphi study, the model shows a diverse set of actors and organisations who share the responsibility for road safety that goes beyond those discussed in road safety policies and strategies. The analysis also shows that, compared to other safety critical domains, there are less formal control structures in road transport and that opportunities exist to add new controls and strengthen existing ones. Relationships that influence rather than control are also prominent. Finally, when compared to other safety critical domains, the strength of road safety controls is brought into question.