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The solidification cooling curve itself as well as its first derivative, and related temperatures, reported to the calculated equilibrium temperatures in stable and metastable solidification systems, are used to predict the solidification characteristics of the cast iron. Silicon, as the most representative cast iron element, and inoculation, as graphitizing metallurgical treatment, have a major influence on the transition from the liquid to the solid state. Six experimental programs are performed, with Si content typically for non-alloyed (&lt, 3.0% Si), low (3.0–3.5% Si) and medium alloyed (4.5–5.5% Si) ductile cast irons, as Si-content increasing, and inoculation simultaneous effects. Silicon is an important influencing factor, but the base and minor elements also affect the equilibrium eutectic temperatures, much more in the Fe-C-Si-Xi stable system (15–20 °C) than in the metastable system (5–10 °C), comparing with their calculation based only on a Si effect (Fe-C-Si system). The highest positive effect of inoculation is visible in non-Si alloyed cast irons (2.5% Si): 9–15 °C for the eutectic reaction and 3 to 4 times increased at the end of solidification (37–47 °C). Increased Si content decreases inoculation power to 7–9 °C for low alloying grade (up to 3.5% Si), with the lowest contribution at more than 4.5% Si (0.3–2.0 °C). 2.5–3.5% Si ductile cast irons are more sensitive to high solidification undercooling, especially at the end of solidification (but with a higher efficiency of inoculation), compared to 4.5–5.5% Si ductile cast irons, at a lower undercooling level, and at lower inoculation contribution, as well.

This paper presents a study on idling production policies in the context of periodic review inventory control. The usefulness of these policies will be demonstrated by means of two different numerical experiments from which we will be able extract some interesting managerial insights, as well some structural properties of the solutions. In the first experiment, the stabilization properties of these policies will be illustrated by means of the stabilization of the Lu&Kumar network. In the second experiment, we will present a stable system for which idling policies achieved a lower operational cost when faced with their non-idling counterparts.

This paper presents an extended state observer (ESO) based repetitive control (RC) to compensate periodic signals, aperiodic disturbances, and uncertainties of the plant with relative degree equal to or greater than zero. Since linear ESO has only two tuning parameters, the proposed controller provides a simple and user friendly solution to complex engineering problems in practice. Moreover, due to the model free approach of a ESO-based control, it can be applied to a wide variety of plants. The design procedures are proposed to ensure a stable system. Various types of disturbances are used in simulations and experiments which show that the ESO-based RC cannot only reject periodic and aperiodic disturbances but also handle the plant parameter uncertainty. The comparison studies demonstrate that the ESO-based RC has superb performance.

Mathematical modelling is the theoretically established tool for developing solar heating systems, e.g. with using transfer functions. If we know the transfer functions of the system, the outlet temperature can be predicted as a function of the input variables (solar irradiance, inlet temperature, environment temperatures), dynamic analysis can be carried out, and stable system control can be effectively designed based on the well-tried methods of control engineering. For these purposes, new, validated transfer functions for solar heating systems are worked out in this study based on a mathematical model, which can be found in the literature and has been applied successfully in the field. The transfer functions are used for dynamic analysis and control design of solar heating systems. The dynamic analysis is presented and the efficiency of the proposed stable control is demonstrated with respect to a real solar heating system.

This study implemented a mobile diagnosing system that provides user-centered interfaces for more precisely estimating and diagnosing engine conditions through communications with the self-developed ECU only for industrial CRDI engine use. For the implemented system, a new protocol was designed and applied based on OBD-II standard to receive engine data values of the developed ECU. The designed protocol consists of a message structure to request data transmission from a smartphone to ECU and a response message structure for ECU to send data to a smartphone. It transmits 31 pieces of engine condition information simultaneously and sends the trouble diagnostic code. Because the diagnostic system enables real-time communication through modules, the engine condition information can be checked at any time. Thus, because when troubles take place on the engine, users can check them right away, quick response and resolution are possible, and stable system management can be expected.

Deployable structures are new prefabricated frames that can be transformed from a closed stage or compact configuration to a predetermined, stable expanded form. The structure is very convenient for transportation and recycling because it can be stretched out, drawn back and disassembled into pieces easily. This paper describes a new deployable structure composed of scissor composite members, each of which consists of universal scissor components, connected by bolts, and braced by pre-tensioned ropes out-of-plane, conforming a stable system. An aluminum-alloy deployable model was fabricated and a test program was carried out under vertical load to evaluate the capacity of the structure. Numerical analysis using FEM was conducted for validation purpose. By studying the stability and capacity of the structure, comprehensive evaluations of the structure were made. Possessing several advantages stated in this paper, deployable structures can be used as semi-permanent and temporary large spatial buildings.

This paper investigates a hybrid structure based synchronous control strategy for multimotor system of shaftless-driven printing press. Many existing algorithms can obtain a stable synchronous system; however, the obtained stable system may encounter a large enough disturbance that can destroy the synchronization. Focusing on this challenging technological problem about how to receive more robust synchronization during steady-state process, this paper first proposes a state-dependent-switching based leader-following control approach, in which synchronization includes two parts, one associated with tracking control for all members, and the other one associated with consensus maintained among followers in the case that one follower loses synchronization with the leader during steady-state motion. By employing the algebra graph theory, matrix theory, and Lyapunov analysis, the convergence and stability of the given multimotor system are proved. Finally, simulation examples are presented to demonstrate the effectiveness and robustness of the theoretical results.

The electric boiler in use at present has a significant system inertia and a serious time-lag at the same time the difficulty of building the mathematical model. In this paper, a study based on the electric boiler is presented to meet the demands of stable system, shorter regulating time and a small overshoot. When fuzzy control is used, regulating time and overshoot always can achieves the specification, but system cause steady-state error. So it comes to a new method of combining them together. The parameters of Kp, Ki and Kd are adjust by fuzzy inference. Experimental results illustrate that the fuzzy PID parameters controller achieved the system performance index. The method of fuzzy PID control is a ideal method.

In order to meet fast and accurate auto-loading, insure stable system, fast minish error, and minish interference signal influence, RBF network adaptive control based on uncertainty compensation is adopted in this thesis. By simulation, simulation results show that this control method can meet control requiements.

Design and synthesis of a nonlinear non-minimum phase supersonic flight vehicle longitudinal dynamics control for g-commands output tracking are presented. Differential geometric approach utilized to outline system relative degree and unstable internal dynamics explored based on the vehicle dynamics transformation to a nonlinear normal form. Unstable internal dynamics are then invoked to identify ideal state reference profiles leading to desired output-tracking problem. Presented compensated internal dynamics converged to a solution on the system center manifold for ideal internal dynamics asymptotically. Finally, sliding mode control employed based on an appropriate sliding manifold to track the reference input while being robust against uncertainties. Simulation results are performed and effectiveness of the designed approach demonstrated as well.

According to the needs of the electrohydraulic servo valve dynamic and static performance testing, designed an automated test system for the test of the static characteristics and dynamic characteristics test combinations together. Its advantage includes a stable system, a high degree of automation, simple operation, and high efficiency, full-featured.

A sliding-mode based repetitive control (SMRC) is presented in this paper to improve tracking periodic reference, rejecting disturbance, and adapting parameter uncertainty such as mass or viscous friction variation. The design method is simple with reduced order algorithm. The stability analysis is conducted, and the design conditions are derived for a stable system. Then, the proposed algorithm is simulated in MATLAB Simulink with different loading conditions. The comparison studies are conducted to demonstrate the effectiveness of the SMRC.

A friction compensator based repetitive control (FCRC) is proposed in this paper to improve tracking periodic reference, and compensating frictions. The stability analysis is conducted, and the design conditions are presented to ensure a stable system. Then, MATLAB Simulink is applied to simulate the proposed algorithm. The comparison studies are conducted to show the effectiveness of the FCRC.

This paper presents a discrete extended state observer (DESO) based repetitive controller (RC) to compensate periodic signals, aperiodic disturbances and uncertainties of the plant with relative degree equal or greater than zero. Since ESO has only two tuning parameters, the proposed controller provides a simple and user friendly solution to complex engineering problems in practice. Moreover, due to the model free approach of ESO-based control, it can be applied to wide variety of plants. The design procedures are proposed to ensure a stable system. Various types of disturbances have been used in simulation which show that the ESO-based RC can not only reject periodic and aperiodic disturbances but also handle the plant parameter uncertainty. The comparison studies demonstrate that the ESO-based RC has superb performance.

Following text is dealing with control possibilities during the moment of transition in to Island Operation of city of Pilsen in view of keeping the balance between generation and consumption. To achieve stable system we use number of control tools and one of them might be the use of DSM (Demand Side Management) as a supportive regulation tool. Current DSM technology that is widely used in Czech Republic is Centralized Ripple Control and this article is focused on the use of this available tool.

On-off control performance of target pumping station was experimented by changing measurement methods for storage level or inflow and operating logic for control system setting. Four scenarios with different measurement methods and operational logic were examined in the Matlab/Simulink environment. Controller`s on-off control repetition that was frequent before has been reduced and more effective and stable system operation was found to be possible with the scenarios. Moreover, defensive operation enforced prevention of floods by changing measurement methods enabled economic operation that made an utmost use of storage volumes.

A 200 W portable polymer electrolyte membrane fuel cell (PEMFC) system is developed. The PEMFC system consists of an air-cooled fuel cell stack module, a fuel supply subsystem, a power management subsystem, and a control electronics subsystem. The control logic is designed for the stable system operation. The system-level performance evaluation discloses that the present PEMFC system provides a rated power output of 200.5 W at 13.4 V with the maximum balance-of-plant (BOP) efficiency of 72%, and maximum system efficiency based on lower heating value (LHV) is 37% at 120.7 W system power output.

This paper investigates the output tracking problem for the single-input single-output (SISO) non-linear system with an output time delay using the twisting sliding mode (SM) control with adaptive gains. Under an appropriate transformation, the SISO non-linear system with relative degree n can be transformed to a relative degree-two system. Pade approximation is involved when considering the output delay problem and this generates a non-minimum phase system, which is considered by the stable system centre approach. Twisting SM control with adaptive gain is used to obtain good output tracking results. A numerical non-linear example is studied to show the effectiveness of this methodology.

PurposeThe purpose of this paper is to present a wireless sensor network system which can monitor human physiological signals of heartbeat rate and body temperature.Design/methodology/approachWhen physiological activity occurs, signals are generated. By measuring these signals, human activity can be monitored. With the help of a new network module named Waseda Hibikino Module‐2, which can transmit not only data, but also based of physiological signals, a wireless sensor network is established.FindingsWhile measuring physiological signals, a stable system is required. From human body to the terminal in a hospital, data must be sent completely, especially for example the heartbeat rate. And a stable transmission protocol must be applied during this process of wireless transmission.Originality/valueThis technology represents a new real‐time monitoring system of human physiological signals. With single data processing, it can prevent different kind of situations before a bad status like a heart attack occurs.

In this paper a heuristic design strategy for stabilizing the satellite attitude has been proposed. It is assumed that the satellite is actuated by a set of mutually perpendicular magnetic coils. Using well-known Lyapunov direct stability method it is shown that the proposed controller causes to a global asymptotic stable system for all near polar orbits. The design procedure is based on analyzing of the conceptual effects of magnetic coils on the satellite attitude motion. Considering these effects lead to some intuitive results which determine the global stabilizing control law. The performance and robustness of the designed controller against actuators saturation and quantization error have been verified using a real-time-hardware–software in-loop (RTHSIL) simulation results. These results show that the global stability can be achieved although some disturbances and restrictions exist. This stabilizing controller can be simply combined with a linear explicit model predictive controller (EMPC) to achieve a full three-axis control law.

Basic principles of a scenario approach application to research of a problem of functioning and development of distributed manufacturing systems (DMS) are stated. The problem of stable system functioning is examined. The formalized concept of the stable scenario functioning DMS is entered. There are examined synergistic and attractive scenarios of development. For synergistic scenarios the modes providing stable, noncrisis development DMS are studied. For attractive scenarios the new type of management technologies is defining: the distributed package management technology (DPM-technology). Methods and examples of formation of such scenarios are offered on the basis of behavior model, submitted in language oriental graphs.

This paper provides an overview of current techniques to allow the industrial systems to automatically adapt to change while maintaining predictable and stable system behaviour. This is performed along the dimensions of simple, dynamic and intelligent reconfiguration and focuses on the physical device and software component levels of the shop floor and in particular, on automatic reconfiguration of programmable logic controller systems. Through an analysis of recent work by the authors and others in this area, the paper identifies the basic requirements for intelligent reconfiguration and the outstanding issues in this area.

The paper presents an observer synthesis method for distributed parameter systems using the transformation bakstepping. The Backstepping method transforms the system into a stable system with a simpler structure. The method is applied to a chemical reactor tube.

This study is about international system and stability. By comparing different theoretical approaches, it discusses the relation between polarity and stability. It is quite common to identify international systems as unipolar, bipolar, and multipolar structures. There is a wide ranging discussion over which one of these structures represents the most stable system. Although multipolar structures were admitted as more stable previously, later the claim of bipolar stability became more common. Recently, the idea that unipolar structures are more stable compared to bipolar structures has gained more ground. This study identifies two main theoretical logics behind the discussions over the relation between polarity and stability: a logic of motivations and a logic of obligations. Although the logic of obligations appears as doing better than the logic of motivations in predicting international stability, it has its own theoretical shortcomings. The study further offers the logic possibilities in order to theoretically explain and predict the relation between polarity and stability. According to this logic, international stability can be considered an outcome of states’ calculations of possibilities

In this paper, We are going to propose the fire protection system using CAN(Controller Area Network). The larger, higher and deeper buildings an, the more dangerous people are when fire happens. We should be aware of the problems of prior fire protection system. Therefore, we construct the embedded system based on CAN communication that is capable of N to N communication, and build independent fire protection system. If the fire is occurred on the building, the problem is that how fast we can detect the fire and put it on by using available system, this is major factor that reduces damage of our wealth. Therefore in this studies, We would like to design more stable system than current system. This system is based on CAN communication which is available N to N communication constructs and designed to compensate for each fault, so that our aim is to reduce the wires of system, cost of installation and to suppose future type fire protection system.

This paper describes important engineering features relating to the seismic evaluation of a school building system in southern Indiana. This evaluation is the first step in identifying deficiencies in the school’s seismic force resisting system and may ultimately be a reference for retrofitting the structure to be in compliance with current design standards. This paper is intended to provide an introduction to the engineering challenges of seismic retrofitting of school structures in the Midwest, with particular reference to the Glenwood Middle School located in Evansville, Indiana. To this end, the paper presents the numerical modeling and analyses to establish a retrofitting scheme that would provide a structurally stable system under seismic loading conditions.

When cast on a chill, cast irons may solidify partly in a stable system and partly in a metastable one. Stable and metastable eutectic solidification are related to different partitioning of alloyi...

Combination of relay feedback experiment and control synthesis is usually a part of autotuning principles. This contribution deals with the relay based identification of continuous time plants because the knowledge of the controlled system parameters is important for the quality of control. The feedback relay schemes can use different types of relays. This paper is focused on biased relay with hysteresis. The controlled system is identified as a first order transfer function because most of industrial plants can be sufficiently approximated by a first order linear stable system with time delay term. The main aim is to analyze the precision of controlled system parameters identification when the feedback relay parameters will vary. Matlab program environment is used for all simulations conducted in this paper. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

Complexity is an inherent property. Measuring and keeping it under control is more logical than practical. Since quality is directly proportional to complexity, a quantitative measure is expected. In software industry, software quality is depending on quality of each phases of its development. As the size of the requirement increases, the design phase complexity increases. This has an adverse affect on software stability. The fundamental design-need in Object Oriented Methodology (OOM) is the well-defined modules and their inter-connectivity, namely, cohesion and coupling. The structure of such artefact is expected to be simple since it influences stability and thereon the module reusability and maintainability. This paper encompasses an investigation on coupling and cohesion which are major design decisive factors and their influence on maintainability and reusability through design stability. The paper provides a hypothetical support on the influence of coupling and cohesion on maintainability and reusability. It also focuses on the further research interests in the same field as a part of through literature survey. The work would contribute to design a high quality product by which the industries sustain themselves in the competitive market.

In this paper, the input-output behavior of a linear stable system is studied in some detail. Some results are presented to make more precise the folklore statement that outputs follow inputs for stable linear systems. Based on these results, it is also discussed how to choose an output and how to fuse a number of sensor outputs, to best track the input in stationarity.

This paper deals with multiobjective control problems for systems whose partial states can be generated by a stable system. For given problems we propose a method to synthesize controllers which explicitly contain the stable system. The synthesis method is proposed as a consequence of the following results : (a) there exists an equivalent problem where partial states of a given generalized plant are exactly available; (b) the resultant controller is constructed by the stable system and another controller for the equivalent problem. The proposing method is advantageous owing to the following reasons : (1) it is possible to synthesize, based on LMIs, controllers which explicitly contain stable systems; those stable systems generate partial states of generalized plants; (2) computational complexity in LMI synthesis can be reduced; (3) computational time to produce control input can be shorten. Moreover, numerical experiments clarify the effectiveness of the proposed method in the case of discrete input delay systems.

The integration of solar PVs which is projected to increase over the years creates concerns over stability. Reverse power flow occurs due to high PV penetration into the power system network. PV placement at proper locations in a transmission system is essential to maintain voltage stability. Improper placement will caused voltage stability of the system to be affected. However, if the PVs are connected at a strategic location it will lead to a more stable system. This paper presents a methodology for PV source placement in the transmission system while maintaining the stability of the. Voltage Stability Index (VSI) will be used as an indicator to measure the stability status of the system. Two test systems will be used for simulation for this research, the IEEE 30 Bus and 57 Bus Test System. The simulation results showed that proper placement of the PV source in the transmission system will lead to better stability to the system.

This paper presents a comparison of the performance of an online inertia estimation method for three different C37.118 compliant PMUs in a laboratory. Inertia is a critical part of ensuring stable system frequency and improving operator awareness of inertia will help preserve high quality frequency control in power systems with high levels of wind generation and converter interfaced generation. This study is necessary as inertia estimation is based on active power and rate of change of frequency measurements recorded immediately after a disturbance. Therefore, the transition time and inherent difficulty of estimating derivatives may mean that not all PMUs can support inertia estimation. Indeed, the results presented show that not all PMUs are capable of supporting inertia estimation. Therefore, it must be acknowledged that the installation of a PMU at a bus does not necessarily imply that it will be possible to perform inertia estimation at that bus.

Recent blackouts of power systems in North America and throughout the world have shown how critical a reliable power system is to modern societies, and the enormous economic and societal damage a blackout can cause. It has been noted that unanticipated operation of protection systems can contribute to cascading phenomena and, ultimately, blackouts. This project developed and field-tested two methods of Adaptive Protection systems utilizing synchrophasor data. One method detects conditions of system stress that can lead to unintended relay operation, and initiates a supervisory signal to modify relay response in real time to avoid false trips. The second method detects the possibility of false trips of impedance relays as stable system swings “encroach” on the relays’ impedance zones, and produces an early warning so that relay engineers can re-evaluate relay settings. In addition, real-time synchrophasor data produced by this project was used to develop advanced visualization techniques for display of synchrophasor data to utility operators and engineers.

The paper shows, with the help of numerical simulation and hardware experiments, that the tracking response of a NLA-based second order PLL would be affected in the presence of additional loop time delay. The inclusion of a phase modulator in the system structure can reduce the adverse effects to some extent, but the design parameters should have to be properly chosen to get a stable system.

The blockage/starvation patterns of known instability examples suggest using local demand information-which is precisely what is provided by the widely advocated kanban approach to flow control in manufacturing systems. Therefore, we have re-analyzed for stability the examples described in the 1990 Kumar-Seidman paper when modified by introducing kanban control. It is found that this does not ensure stability and, in fact, some interesting new instability phenomena arise. Counterintuitively, it is possible that increasing some reserve in a stable system may induce instability.

Reliability of production processes is a key issue to ensuring a stable system operation, increasing a product quality, and reducing production losses. In this paper we proposed a tool for the analysis of faults in a process and the definition of the most effective way for their elimination. In the centre of the offered framework is FMEA - a reliability analysis type, the most widely used in enterprises. In the paper it is proposed to extend the FMEA by introducing a classification of faults and an estimation of expert opinions for the FMEA parameters. By using the Pareto analysis, it is possible to extract from the FMEA the most critical process failures. To analyse these faults through the Bayesian Belief Network is the most effective way to address them. The Bayesian network structure duplicates the faults classifier structure, therefore this method fits well for this analysis. BBN enables to calculate the probabilities for each fault group based on the error of the manufacturing processes probability. For a more complete analysis of a process we used a structural and dynamic analysis for revealing the bottlenecks of the process, as well as the Fault Tree Analysis and Reliability Block Diagram, which may be built on the base of a structural model of a process and gives the reliability of the system on the whole. On the base of the FMEA data it is possible to calculate an optimal plan of the equipment maintenance for a current process. The framework for the analysis of the production process enables companies of machinery manufacturing enterprises to analyse processes as a whole as well as its parts for efficient forecast of the production process improvement.DOI: http://dx.doi.org/10.5755/j01.mech.18.6.3168

From engineering point of view, a construction can be named tall when its height leads to significant influence of lateral forces of wind and earthquake on its design. Also, contrary to gravity forces, the effect of lateral forces on constructions is so variable and increases along with height. Three fundamental factors should be considered in designing all tall buildings are resistance, rigidity and stability. In designing tall buildings, construction system should be consistent with these requirements. The need to resistance is the dominant factor in designing short buildings. But, increasing the height leads to more necessity of rigidity and stability. Therefore, in a tall building structure, the stable system against lateral and erect loads differs in terms of height of structure, kind of use and nature of forces. In this study, first, central concrete core system was introduced as the lateral carrier system. Then, some studies were reviewed focusing on the behavior of this specific system. Meanwhile, building models and implementing analytic analyses using ETABS were presented. Finally, data were compared to find ideal results. Keywords: concrete center core; lateral resisting system; time history analysis; rms results; modal analysis

System Integrity Protection Schemes (SIPS) are a widely used solution to the problems in operating increasingly stressed power systems. This leads to the application of large numbers of SIPS on many national networks, which results in an increased probability of undesirable and unplanned interactions amongst the SIPS. Recent electrical disturbances evidenced that these events decrease power system reliability and increase the probability of widespread incidents. This paper proposes a procedure for assessing the risk caused by the interaction between different SIPS on the same or neighbouring networks. The probability of adverse operation of each individual SIPS is used to evaluate the probability of an interaction between the SIPS. This method is illustrated using a small power system, where the installation of a wind park increases system stress and SIPS are used to ensure stable system operation.

When distributed generation (DG) units operate in a microgrid environment, there is a need for coordinated operation between the DGs, the utility grid and the loads. A Microgrid Central Controller (MGCC) can keep track of the status from the systemic point of view and command the local microsource controllers (MC) to ensure system stability. In various modes of operation, vis-a-vis grid-connected, islanded and during transition from grid-connected to islanded mode and vice versa, the MGCC can support the MCs by feeding the necessary information to contribute towards stable system operation. This paper discusses the implementation of the MGCC for a laboratory test system.

In this paper we have described the novel approach for energy efficient configuration using IEEE 802.16e Standard. Obtained results provide an explicit picture of the best system configuration under different environmental conditions that allows to save energy while providing required data rate. This leads to the stable system condition and decreasing power consumption due to adjusting to more energy efficient state.

In design and optimization problems, a solution which is stable enough in its variability in presence of the perturbation of the parameters/variables of the model is called robust. In engineering design optimization, the designer may sacrifice the optimal solution for the robust one in order to set a stable system design. Although in literature there are methods for capturing such solution, they do not provide the designer with a direct and systematic control over the level of the required robustness. In this paper a new robust design methodology is introduced in the context of the multiobjective optimization problem. The proposed approach not only is able to capture the robust design but also can introduce a manipulation for controlling the extent of the design’s robustness based on the designer preferences while dealing with the fuzzy and interval values uncertainty. The presented method is different form its other counterparts as it does not average the vicinity of the current design nor change/add any new constraint to keep the feasibility of the design despite of variation. On the contrary, only a special tunable objective function is constructed to incorporate the preference of the designer on the extent of the demanded robustness efficiently. The benefits of the new approach are discussed and, to show its effectiveness, it is tested on a well known engineering design problem and the results are presented. The proposed approach is of immediate use for any engineering design, where the designer would like to study a set of robust solution with different levels and to choose the most appropriate ones amongst.

The problem of causal output tracking and observation in non-minimum phase nonlinear systems is studied. The extended method of Stable System Center (ESSC) is used in two-fold manner: i) to generate reference profile for unstable internal states; ii) to estimate states of unstable internal dynamics. Two applications of the proposed technique are considered for illustration purposes: output voltage tracking in a nonminimum phase DC/DC electric power converter and output tracking in SISO systems with time-delayed output feedback. A variety of traditional and higher-order sliding mode (HOSM) control and observation methods is employed in the majority of algorithms. Most of the theoretical results are covered by numerical simulations.

In this paper, we introduce machine-job incidence (MJI) matrix that can be obtained from Steward sequencing matrix and Kusiak machine-part incidence matrix. Methods for determination of structural properties of free-choice multiple reentrant systems (FMRF) are proposed and an explanation on how the content (number of active jobs) of those structures can be controlled. This paper gives a new method on how to determine if allocation of resources, in a form of repeatable sequences, gives stable system behavior. Although efficiency of the proposed methods have been demonstrated on examples involving manufacturing workcells, the method can be used for other discrete-event systems as well, as long as the system under study belongs to FMRF class.

In this paper a coverage scheme consisting of both fixed and configurable beams is proposed for relieving of hot spot in HAPS CDMA systems. According to different user distribution, the system capacity is optimized by embedding configurable beams in fixed beams rationally and adjusting the position and size of them efficiently. The numerical results show that a higher and more stable system capacity is expectable despite variation of user distribution, and large number of beams are also economized. This good performance especially appears in solving the problem of the hot spot.

Many tuning strategies for model predictive control algorithms have been proposed in the literature depending on the conditionality of the system matrix and the choice of its cost function. In this paper, the properties of a new predictive controller termed extended predictive control (EPC) are investigated and presented. These properties are important to the understanding of the unique tuning strategy of EPC. EPC is based on the assumption of infinite horizon which is preferable to guarantee stability. The EPC properties are derived using a second order plant with relatively large dead time and is applicable to any open-loop stable system. The tuning strategy of EPC was applied to generalized predictive control with good results.

Effective control of load swing in shipboard crane has been the subject of interest to both commercial and military applications. The difficulty of the control problem due to uncertainty in the nonlinear models of the crane, and the presence of numerous disturbance sources in the environment is well documented. Model predictive control (MPC) has been successfully applied in many real-world industrial applications due to its inherent robustness to modeling errors and the ability to explicitly include constraints in the problem formulation. This paper proposes a formulation that enables the use of a purely MPC-based technology for the control of load swing in shipboard cranes in real-time. We show that a decomposition of the crane model into linear state dynamics, and nonlinear static output mapping enables the use of the MPC approach in a computationally efficient way. We use our newly developed nonlinear solver to enhance the computational properties of the MPC-based approach. Simulation results are presented to demonstrate the feasibility of the proposed approach. To the best of our knowledge, this is the first successful implementation of a purely MPC-based controller for the load swing in a shipboard crane. The solution presented in this paper is ideally suited for indirect adaptive control and hence suggests an exciting opportunity for a versatile controller in a difficult application.

Results are presented from a preliminary study to determine the potential benefits of utilizing dynamic inversion inspired by a structural analogy for formation control of a system of vehicles. Vehicles are modeled as unconstrained mass particles under the influence of control forces in an inertial reference frame. For a system of particles restricted to motion in one dimension only, equations of motion are developed, and a corresponding dynamic inversion control law is proposed. A dissipative mechanical structure analogy is used to establish a family of feedback controllers. The conditions for global asymptotic stability are presented, and information requirements are discussed. It is shown that a stable system can be generated with each particle obtaining measurements for the mass center location of the system, and the position of the particles immediately next to it. A simulation of the response of a system to initial errors and desired trajectories using the proposed control law is presented yielding satisfactory results.

This paper is about hybrid methods of combining energy function analysis and conventional time-domain simulation for transient stability assessment. In particular, a new approach called marginally unstable injection (MUI) for developing a more accurate transient stability index is presented. An energy margin for transient stability assessment based on a reduced energy function is formulated. One implementation of the proposed approach is to use a feedback-controlled sequence of short pseudo-faults to impel the stable system to a marginally unstable state. The conceptual differences between MUI and some earlier approaches of hybrid methods are discussed. For illustrative purposes, the technique developed is applied to a 700-bus North America system. Some numerical results are presented.

In this paper we address the problem of nonlinear formation flight control design using a leaderfollower configuration. The problem is to design a formation hold autopilot for the follower vehicle such that the relative positions between the leader and the follower are maintained close to their desired values. We first present a nonlinear control algorithm based on the dynamics of the relative positions between the two vehicles. Such a control law results in a locally stable system since the corresponding dynamic model has a singularity in the state space. We next propose a singularity-free formation control algorithm based on a new error formulation in the inertial frame. We prove global stability of the overall system, and demonstrate favorable properties of the proposed formation control algorithm through computer simulations.