Temat: time control - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Optimal sliding control of mobile manipulators
Autorzy:: Galicki, M.
Tematy:: mobile manipulator
trajectory tracking
finite time control; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/201159.pdf Link otwiera się w nowym oknie
Opis:: The paper adresses optimal control problem of mobile manipulators. Dynamic equations of those mechanisms are assuemd herein to be uncertain. Moreover, unbounded disturbances act on the mobile manipulator whose end-effector tracks a desired (reference) trajectory given in a task (Certesian) space. A compytionally efficient class of two-stage cascaded (hierarchchical) control algotithms based on both the transpose Jacobian matrix and transpose actuation matrix, has been proposed. The offered control laws involve to kinds of non-singular terminal sliding mode (TSM) manifolds, which were also introduced in the paper. The proposed class of cooperating sub-controllers is shown to be finite time stable be fulfilment of practically reasonable assumptions. The performance of the proposed control strategies is illustated on an exemplary mobile manipulator whose end-effector tracks desired trajectory.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Improving data access security by server-side functional extensions
Autorzy:: Miłosz, M.
Draganek, D.
Tematy:: security
data access
access time control
password policy; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/102072.pdf Link otwiera się w nowym oknie
Opis:: All Database Management Systems used in the industry provide secure access to data at the server level. The level of security is influenced by technology, security model, password encryption method, password strength and others. The human factor – unreasonable behaviour of users – also has a significant impact on safety. Developers of database applications often implement their security policy by limiting the risk caused by users. This implementation has a disadvantage – it does not work outside of the application. A large number and variety of applications that work with the database server may then create a security gap. The paper presents the authors’ extensions of the functional features implemented in the Oracle database server, increasing the security of data access. The implemented methods of controlling the time of user access to data and limiting the use of serial and modular passwords are also discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Speed Analysis of a Digital Controller in Time Critical Applications
Autorzy:: Piątek, P.
Grega, W.
Tematy:: digital control
real-time control
time-critical systems
FPGA
magnetic levitation
timing model; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Powiązania:: https://bibliotekanauki.pl/articles/384616.pdf Link otwiera się w nowym oknie
Opis:: Traditionally, control algorithms are designed without a consideration of their real-time implementation details. The performance of a digital control system, besides the sampling period, depends on many variables, such as the control loop execution time, jitter, complexity of the control algorithm etc. In this paper attention is focused on the inter-action of the parameters of the scheduled tasks and on the performance of control loops closed with digital controller. A design approach that is based on the relative speed classification of the control system has been proposed. The approach is illustrated by the analysis of control systems developed for laboratory magnetic levitation process.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Using Pre-emption For Dependable Urban Vehicle Traffic
Autorzy:: Letia, T.
Barbu, S.
Dinga, F.
Tematy:: urban vehicle traffic control
real time scheduling
traffic congestion
real time control
dependability; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Powiązania:: https://bibliotekanauki.pl/articles/384863.pdf Link otwiera się w nowym oknie
Opis:: A new approach for design and implementation of urban vehicle control system is proposed. The vehicle streams on lanes are considered similar with the streams of instructions in multitask programs. Real-time scheduling algorithms are used to allocate the green lights to phases. An adaptive component is used to calculate new vehicle flow parameters when a failure appears as a consequence of an accident. The real-time schedulers use the parameters to obtain new feasible resource allocations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Interval arithmetic-based fuzzy discrete-time crane control scheme design
Autorzy:: Smoczek, J.
Tematy:: interval arithmetic
discrete-time control
fuzzy control
pole placement
anti-sway control; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/201270.pdf Link otwiera się w nowym oknie
Opis:: In many manufacturing segments, container terminals and shipping yards the automation of material handling systems is an important element of enhancing productivity, safety and efficiency. The fast, precise and safe transfer of goods in crane operations requires a control application solving the problems, including non-collision trajectory planning and limitation of payload oscillations. The paper presents the interval arithmetic-based method of designing a discrete-time closed-loop anti-sway crane control system based on the fuzzy interpolation of linear controller parameters. The interval analysis of a closed-loop control system characteristic polynomial coefficients deviation from their nominal values is proposed to define a minimum number of fuzzy sets on the scheduling variables universe of discourse and to determine the distribution of triangular-shaped membership functions parameters, which satisfy the acceptable range of performances deterioration in the presence of the system’s parameters variation. The effectiveness of this method was proved in experiments conducted using the PAC system on the laboratory scaled overhead crane.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Dead-beat and reaching-law-based sliding-mode control of perishable inventory systems
Autorzy:: Ignaciuk, P.
Bartoszewicz, A.
Tematy:: sliding-mode control
inventory control
perishable inventories
discrete-time control systems; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/202382.pdf Link otwiera się w nowym oknie
Opis:: In this paper we consider the problem of efficient control of inventory systems with perishable goods. In the analyzed setting the deteriorating stock at a distribution center used to fulfill unknown, time-varying demand is replenished with delay from a supply source. The challenging issue is to achieve the high service level with minimum costs when the replenishment orders are procured with lead-time delay spanning multiple review periods. On the contrary to the typical heuristic approaches, we apply formal methodology based on discrete-time sliding-mode (SM) control. The proposed SM controller with the sliding plane selected for a dead-beat scheme ensures that the maximum service level is obtained in the system with arbitrary delay and any bounded demand pattern. In order to account for the supplier capacity limitations in the systems with input constraints, we also develop an alternative control strategy based on reaching law. Both controllers achieve a given service level with smaller holding costs and reduced order-to-demand variance ratio as compared to the classical order-up-to policy.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Comparative Simulation of the Production Flow with the Implementation of Kanban and DBR
Autorzy:: Tomaszewska, Klaudia
Tematy:: modeling
control optimization
real-time control
process control
lean manufacturing
theory of constraints; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/24200493.pdf Link otwiera się w nowym oknie
Opis:: Currently, we live in a culture of being overly busy, but this does not translate into efficiency, speed of implementation of the actions taken. Enterprises are constantly looking for methods and tools to make them more efficient. The most popular method of production management is Lean Manufacturing, less known is Theory of Constraints. This work is a continuation of the research on the comparison of these methods with apply a computer simulation, which the analyzed production process in the selected enterprise, after 24 hours and week. An attempt was made to simplify the comparison of the methods based on the obtained simulation in terms of costs. In analyzed case, more advantageous solution is to use the DBR method. To produce various orders that do not require 100% production on the bottleneck position, the use of Kanban is a frequent practice as it provides greater flexibility in order execution.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Discrete-time control systems on homogeneous spaces: partition property
Autorzy:: Jordan, J.
Tematy:: discrete-time control systems
inverse iteration
partition property
system semigroup; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Badań Systemowych PAN
Powiązania:: https://bibliotekanauki.pl/articles/970004.pdf Link otwiera się w nowym oknie
Opis:: If the system semigroup of a control system is a roup, the system has the partition property, i.e., the reachable sets form a disjoint partition in the state space. The converse is ot true in general. In this work we give sufficient conditions for le partition property for a family of discrete-time control systems on homogeneous spaces. We apply our results to Inverse Iteration systems on flag manifolds, which are closely related to numerical aIgorithms.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Work Time Control and Mental Health of Workers Working Long Hours: The Role of Gender and Age
Autorzy:: Żołnierczyk-Zreda, D.
Bedyńska, S.
Warszewska-Makuch, M.
Tematy:: long working hours
work time control
somatic complaints
anxiety
social dysfunction
depression; Pokaż więcej
Wydawca:: Centralny Instytut Ochrony Pracy
Powiązania:: https://bibliotekanauki.pl/articles/89996.pdf Link otwiera się w nowym oknie
Opis:: The aim of this study was to examine the relationship between work time control and mental health in workers working long hours. The study also attempted to show how that relationship depended on age and gender. Three hundred and six white-collar workers doing clerical work for over 8 h daily were diagnosed on work time control and mental health with the 28-item General Health Questionnaire. The results of an analysis of variance (ANOVA) showed that participants working long hours but having high control over their work time had a significantly higher level of their mental health with regard to somatic complaints and anxiety and marginally higher with regard to social dysfunction than workers with low control over their work time. Male and female workers reported different problems with their mental health depending on what age (stage of life) they were at. It is hypothesized that the work–family conflict, inability to fulfil social commitments and poor working conditions can influence those effects.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: An iterative method for time optimal control of dynamic systems
Autorzy:: Kashiri, N.
Ghasemi, M. H.
Dardel, M.
Tematy:: dynamic systems
optimal control
time optimal control
bounded control inputs; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/229435.pdf Link otwiera się w nowym oknie
Opis:: An iterative method for time optimal control of a general type of dynamic systems is proposed, subject to limited control inputs. This method uses the indirect solution of open-loop optimal control problem. The necessary conditions for optimality are derived from Pontryagin's minimum principle and the obtained equations lead to a nonlinear two point boundary value problem (TPBVP). Since there are many difficulties in finding the switching points and in solving the resulted TPBVP, a simple iterative method based on solving the minimum energy solution is proposed. The method does not need finding the switching point so that the resulted TPBVP can be solved by usual algorithms such as shooting and collocation. Also, since the solution of TPBVPs is sensitive to initial guess, a short procedure for making the proper initial guess is introduced. To this end, the accuracy and efficiency of the proposed method is demonstrated using time optimal solution of some systems: harmonic oscillator, robotic arm, double spring-mass problem with coulomb friction and F-8 aircraft.
Dostawca treści:: Biblioteka Nauki

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