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1

Dynamic performance and stability analysis of an active inerter-based suspension with time-delayed acceleration feedback control

Wang Yong, Jin Xian-Yu, Zhang Yun-Shun, Ding Hu, Chen Li-Qun

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 2

art. no. e140687

EN

An active inerter-based suspension with acceleration feedback control is proposed in this paper, the time delay generated in the controllers and actuators is considered, which constitutes the time-delayed active inerter-based (TDA-IB) suspension. The dynamic equation of the TDA-IB suspension is established and is a neutral type of delay differential equation (NDDE) in which the time delay exists in the highestorder derivative. The stability analysis is conducted by calculating the number of unstable characteristic roots based on the definite integral stability method, the stable and unstable regions are determined. The effect of time delay and feedback gain on the dynamic performance of the TDA-IB suspension under harmonic, random, and shock excitations is studied in detail and compared with the parallel-connected inerterbased (PC-IB) and traditional suspensions. The results show that the TDA-IB suspension is asymptotically stable for smaller feedback gain and time delay, through increasing the feedback gain, the stable regions shrink, and a smaller time delay could cause the system to become unstable. Furthermore, the time delay could regulate the resonance peak around the unsprung mass natural frequency and generate multiple high-frequency resonance peaks. If the time delay is chosen appropriately and falls into the stable range, the TDA-IB suspension could improve the dynamic performance for the suspension stroke and dynamic tire load while having a deterioration for the vehicle body acceleration compared with the PC-IB and traditional suspensions.

2

Uniform exponential stabilization of distributed bilinear parabolic time delay systems with bounded feedback control

Tsouli Azzeddine, Ouarit Mostafa

Archives of Control Sciences

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2022

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Vol. 32, No. 2

257--278

EN

In this paper we deal with the problem of uniform exponential stabilization for a class of distributed bilinear parabolic systems with time delay in a Hilbert space by means of a bounded feedback control. The uniform exponential stabilization problem of such a system reduces to stabilizing only its projection on a suitable finite dimensional subspace. Furthermore, the stabilizing feedback control depends only on the state projection on the finite dimensional subspace. An explicit decay rate estimate of the stabilized state is given provided that a non-standard weaker observability condition is satisfied. Illustrative examples for partial functional differential equations are displayed.

3

A fault estimation and fault-tolerant control based sliding mode observer for LPV descriptor systems with time delay

Hamdi Habib, Rodrigues Mickael, Rabaoui Bouali, Benhadj Braiek Naceur

International Journal of Applied Mathematics and Computer Science

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2021

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Vol. 31, no. 2

247--258

EN

This paper considers the problem of fault-tolerant control (FTC) and fault reconstruction of actuator faults for linear parameter varying (LPV) descriptor systems with time delay. A polytopic sliding mode observer (PSMO) is synthesized to achieve simultaneous reconstruction of LPV polytopic descriptor system states and actuator faults. Exploiting the reconstructed actuator faults and state estimates, a fault-tolerant controller is designed to compensate the impact of actuator faults on system performance by stabilizing the closed-loop LPV delayed descriptor system. Besides, the controller and PSMO gains are obtained throughout the resolution of linear matrix inequalities (LMIs) using convex optimization techniques. The developed PSMO could force the output estimation error to converge to zero in a finite time when the actuators faults are bounded through the reinjection of the output estimation error via a nonlinear switching term. Simulation results applied to a given numerical system are presented to highlight the superiority and effectiveness of the proposed approach.

4

Performance of Mn/Bi2O3 Pyrotechnic Time Delay Compositions

Tichapondwa Shepherd M., Guo Shasha, Roux Willem E.

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 1

46--62

EN

Chemical time delay detonators are used widely in mine blasting applications. In order to achieve effective blasting, detonations must follow a precisely controlled timing sequence in a specified firing pattern. Silicon fuel-based pyrotechnic compositions are widely used in mining detonators and are well studied. However, some of these formulations are deemed to be problematic, as they contain heavy metals which are bio-accumulative and toxic to the environment. Therefore, there is need to explore alternative formulations which are suitable for these applications. Manganese-fueled systems are attractive due to their metallic properties and several oxidation states of the manganese fuel. This study focused on characterizing the burn properties of Mn/Bi2O3 compositions for slow to intermediate time delay applications. The compositions supported combustion in the 25 to 55 wt.% Mn range in an inert helium atmosphere. Burn rates between 2.5 and 11.2 mm·s–1 were recorded in open burn tests, whilst closed burn tests in glass tubes resulted in burn rates of 6.3 to 11.2 mm·s–1. Both X-ray diffraction analysis of the reaction products and thermodynamic simulations confirmed that MnO and Bi are the main reaction products, with unreacted Mn and Bi2O3 also being detected. This suggests that the dominant reaction for this composition is a simple thermite-type reaction.

5

Design of decoupled pi controllers for two-input two-output networked control systems with intrinsic and network-induced time delays

Mohamed-Vall Ould Mohamed

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 4

201--208

EN

Proportional integral controller design for two-input two-output (TITO) networked control systems (NCSs) with intrinsic and network-induced time delays is studied in this paper. The TITO NCS consists of two delayed sub-systems coupled in a 1-1/2-2 pairing mode. In order to simplify the controller design, a decoupling method is first applied to obtain a decoupled system. Then, the controllers are designed based on the transfer function matrix of the obtained decoupled system and using the boundary locus method for determining the stability region and the well-known Mikhailov criterion for the stability test. A comparative analysis of the designed controllers and other controllers proposed in previous literature works is thereafter carried out. To demonstrate the validity and efficacy of the proposed method and to show that it achieves better results than other methods proposed in earlier literature works, the implementation in simulation of Wood–Berry distillation column model (methanol–water separation), a well-known benchmark for TITO systems, is carried out.

6

Protection system for induction motor based on Sugeno Inference

Achou Nadia, Tandjaoui Mohammed Nasser, Benachaiba Chellali, Bendjebbar Mokhtar

Przegląd Elektrotechniczny

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2020

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R. 96, nr 3

138--141

EN

The induction motor is a most important drive in the production area. These motors are used in various industrial applications. They can be protected from the different mechanical and electrical faults using different protection systems. The protection is very important to detect abnormal motor running conditions such as over current, over voltage, overload, over temperature, and unbalance conditions. In the classical protection systems, the time delay is adjusted constantly without considering the fault level. This paper presents protection system for induction motor based on Sugeno Inference. The time delay is computed by this intelligent protection for different faults. The obtained results are interesting and show the interest of the proposed intelligent protection.

PL

W artykule zaprezentowano system zabezpieczeń silnika indukcyjnego bazujący na Sugeno Inference. Określano opóźnienie czasowe dla różnych rodzajów błędów. W stosunku do istniejących systemów proponowany system umożliwia bardziej precyzyjne określenie błędów.

7

Calibration of ultrasound tester delay time by cutting a wooden beam

Karwat Zbigniew, Rousek Miroslav

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2020

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No. 110

131--139

EN

Obtaining precise and reliable test results requires specific tools on one hand, and at the same time, reliability of the results should not be questioned. One of the necessary steps to achieve this goal is the calibration of the measuring device before the test. This article describes an experiment involving calibration of the device by an independent method called cutting beam calibration carried out on the ultrasonic material tester UMT 01. The standard calibration of this device is carried out by using a dedicated metal disc as a template. Calibration of the tester consisted of determining the time delay of the measured signal. The obtained results were used to prepare charts and to determine of signal time delay, called correction, which also allowed determining the velocity of ultrasonic wave in the tested material in three ways. The experiment was conducted on samples of three species of wood: Norway spruce, Scots pine and sycamore. The velocity of ultrasonic wave from research was compared with literature data.

PL

Kalibracja ultradźwiękowego testera materiałów przy pomocy przycinanej belki drewnianej. Celem badań było sprawdzenie kalibracji ultradźwiękowego testera materiałów UMT 01 bez użycia wzorca fabrycznego. Sprawdzenie to polegało na pomiarach całkowitych czasów przebiegu sygnału w skracanych próbkach. Skracanie próbek odbywało się naprzemiennie i równomierne odcinanie jej końców. Badania przeprowadzono z użyciem ultradźwięków przy zastosowaniu impulsowego trybu pracy testera. Kalibracja została przeprowadzona na trzech gatunkach drewna: sosny zwyczajnej, świerka pospolitego i klonu jaworu. Wyniki pomiarów poddano analizie. Ustalono, iż proponowana niezależna metoda kalibracji jest zgodna i równie dokładna jak kalibracja wzorcem dedykowanym. Równocześnie badania te potwierdziły, iż używanie poliakrylowego żelu ultrasonograficznego podczas badań istotnie zwiększa precyzję pomiarów. Na mocy porównania wyników badań z danymi źródłowymi oraz dokładnego przeglądu literatury, można stwierdzić, iż w zagadnieniu ultrasonografii drewna zdarza się słabe doprecyzowanie rodzaju prędkości mierzonych fal (grupowej, fazowej, impulsowej). Uporządkowanie i rozstrzygnięcie rodzaju prędkości mierzonych, znacznie ułatwiłoby interpretację i metaanalizę danych z różnych prac.

8

Badania porównawcze działania spłonek elektrycznych w funkcji mocy impulsu pobudzającego

Faryński A., Kaźmierczak R., Kwaśniak T., Olejniczak E., Urbaniak R., Ziółkowski Z.

Problemy Techniki Uzbrojenia

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2018

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R. 47, z. 148

115--135

PL

Badano inicjowanie spłonek elektrycznych impulsami o stałej energii i 3 poziomach mocy: P ~1 W, P ~1 kW do P ~1 MW. Porównywano działanie spłonek z mostkiem metalicznym połączonych z zapłonnikiem (SI), pobudzanych ze stałą energią dysponowaną ok. 20 mJ i spłonek z rezystancją rozłożoną w mieszaninie pirotechnicznej (SII), pobudzanych ze stałą energią dysponowaną ok. 200 mJ. Zobrazowano kilkukrotne „podimpulsy” prądowe prowadzące do jednego pobudzenia SII. Średnie opóźnienie zadziałania malało od 8,7 ms przy P ~1 W do 133 µs przy P ~1 MW dla SI oraz od ok. 90 µs przy P ~1 kW do ok. 50 µs przy P ~1 MW dla SII, przy czym od P ~1 kW dla obu rodzajów spłonek praktycznie nie zmieniało się. Przedyskutowano mechanizmy pobudzenia i czynniki wpływające na mierzone opóźnienia. Wyznaczono średnie energie pochłonięte do chwili zadziałania: 5-7 mJ dla SI, ok. 15 mJ dla SII. Oszacowano końcowe ciśnienia: 300-400 bar w korpusach spłonek/zapłonników.

EN

Initiation of electric primers by pulses of constant energy at 3 different levels of power from P ~1 W to P ~1 MW was investigated. Actions of primers with metallic electric bridge (SI) connected to an exploder and initiated by permanent disposable energy of ca. 20 mJ were compared to primers with the resistance distributed within a pyrotechnic mixture (SII) initiated by permanent disposable energy of ca. 200 mJ. A series of current “sub-pulses” at one activation of SII is shown. Average delay of activation was reduced from 8.7 ms at P ~1 W to 133 mikro s at P ~1 MW for SI, and from ca. 90 mikro s at P ~1 kW to ca. 50 mikro s at P ~1 MW for SII, to be in practice unchangeable above P ~1 kW for two types of primers. Mechanisms of initiation and factors influencing the measured delays were discussed. Average energies absorbed to the moment of activation were determined: 5-7 mJ for SI, and ca.15 mJ for SII. Final pressures inside the casing of primers/igniters were estimated on the level of 300-400 bar.

9

Enhanced IMC synthesis for tracking control of magnetic levitation system

Elumalai V. K., Subramanian R. G., Reddipogu J. S. D., Srinivasan S., Agrawal S.

Archives of Electrical Engineering

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2018

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Vol. 67, nr 2

293–-306

EN

This paper presents an enhanced internal model control (EIMC) scheme for a time-delayed second order unstable process, which is subjected to exogenous disturbance and model variations. Even though the conventional internal model control (IMC) can provide an asymptotic tracking response with desired stability margins, the major limitation of conventional IMC is that it cannot be applied for an unstable system because a small exogenous disturbance can trigger the control signal to grow unbounded. Hence, modifying the conventional IMC structure to guarantee the internal stability, we present an EIMC scheme which can offer better trade-off between setpoint tracking and disturbance rejection characteristics. To improve the load disturbance rejection characteristics and attenuate the effect of sensor noise, we solve the selection of controller gains as an H∞ optimization problem. One of the key aspects of the EIMC scheme is that the robustness of the closed loop system can be tuned via a single tuning parameter. The performance of the EIMC scheme is experimentally assessed on a magnetic levitation plant for reference tracking application. Experimental results substantiate that the EIMC scheme can effectively counteract the inherent time delay in the model and offer precise tracking, even in the presence of exogenous disturbance. Moreover, by comparing the trajectory tracking performance of EIMC with that of the proportional integral velocity (PIV) controller through cumulative power spectral density (CPSD) of the tracking error, we show that the EIMC can offer better low frequency servo response with minimal vibrations.

10

Określenie wpływu czasu przechowywania/eksploatacji na parametry pracy spłonek pironabojów foteli katapultowych

Długołęcki A., Dębiński J., Faryński A., Kwaśniak T., Słonkiewicz Ł.

Problemy Techniki Uzbrojenia

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2017

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R. 46, z. 144

79--89

PL

Praca niniejsza dotyczy pobudzania za pomocą uderzaka grawitacyjnego (UG) grup spłonek pironabojów foteli katapultowych z roczników produkcyjnych różniących się datą produkcji o około 12-13 lat. W czasie prób przy energii dysponowanej UG, odpowiadającej energii sprężynowych mechanizmów strzałowych (SMS) fotela zmierzono średnie wartości: opóźnienia zadziałania Δt ~ 410 µs i nadciśnienia 1 i 1,8 bar przed i po odbiciu w komorze wybuchowej o objętości 460 cm3 oraz medianę energii Eśred wymaganej do pobudzenia spłonek. Stwierdzono wzrost Eśred od około 290 mJ o ok. 20% w ciągu 10 lat, co oznacza odpowiedni spadek wrażliwości. Pozostałe mierzone wielkości nie wykazywały zauważalnej zależności od czasu użytkowania. Zbadano zależność opóźnienia zadziałania od prędkości początkowej v0 iglicy w zakresie od ok. 1 m/s do zbliżonej do występującej w SMS (7-10 m/s). Zależność ta jest zbliżona do Δt ~ 1 / v0, stwierdzanej dla innych typów spłonek pobudzanych uderzeniowo.

EN

The paper dwells on using a gravitation striker (GS) to initiate collections of ejection cartridge primers with dates of manufacture spanning by ca. 12-13 years. During the tests at the energy provided by the GS corresponding to spring firing mechanisms (SFM) of the seat, the average values of activation delay time Δt 410 µs and the overpressure 1.0 and 1.8 bar before and after the bouncing and the median energy Eaver required for the initiation of the primers were measured in the explosive chamber having the volume 460 cm3. The increase of Eaver from 290 mJ by ca. 20% during 10 years indicates the fall of sensitivity. The remaining measured values have not shown any clear dependence on the life time. The dependence of activation time delay between the striker initial velocities v0 of ca. 1 m/s and values of SFM (7-10 m/s) was also investigated. The dependence is close to Δt ~ 1 / v0 observed for other types of percussion primers.

11

The fastest, simplified method of estimation of the largest Lyapunov exponent for continuous dynamical systems with time delay

Balcerzak M., Pikunov D.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

985--994

EN

This paper focuses on the applications of the new method of estimation of the Largest Lyapunov exponent. The method has been adapted to continuous dynamical systems with time delay. The paper presents efficiency of the new method in comparison with classical algorithms of LLE estimation. Computation times and convergence rates have been compared with the typically used method. It has been revealed in this paper that for the van der Pol oscillator, application of the new method increases the efficiency of calculations by 28% comparing to the classic one. Therefore, authors claim that the method presented in this paper is the fastest one in the assumed range of applications.

12

Stability analysis of nonlinear time-delayed systems with application to biological models

Kruthika H. A., Mahindrakar A. D., Pasumarthy R.

International Journal of Applied Mathematics and Computer Science

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2017

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Vol. 27, no. 1

91--103

EN

In this paper, we analyse the local stability of a gene-regulatory network and immunotherapy for cancer modelled as nonlinear time-delay systems. A numerically generated kernel, using the sum-of-squares decomposition of multivariate polynomials, is used in the construction of an appropriate Lyapunov–Krasovskii functional for stability analysis of the networks around an equilibrium point. This analysis translates to verifying equivalent LMI conditions. A delay-independent asymptotic stability of a second-order model of a gene regulatory network, taking into consideration multiple commensurate delays, is established. In the case of cancer immunotherapy, a predator–prey type model is adopted to describe the dynamics with cancer cells and immune cells contributing to the predator–prey population, respectively. A delay-dependent asymptotic stability of the cancer-free equilibrium point is proved. Apart from the system and control point of view, in the case of gene-regulatory networks such stability analysis of dynamics aids mimicking gene networks synthetically using integrated circuits like neurochips learnt from biological neural networks, and in the case of cancer immunotherapy it helps determine the long-term outcome of therapy and thus aids oncologists in deciding upon the right approach.

13

Optimal robust stabilizer design based on UPFC for interconnected power systems considering time delay

Koofigar H. R., Isazadeh G.

Archives of Electrical Engineering

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2017

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Vol. 66, nr 3

459--474

EN

A robust auxiliary wide area damping controller is proposed for a unified power flow controller (UPFC). The mixed H2 /H∞ problem with regional pole placement, resolved by linear matrix inequality (LMI), is applied for controller design. Based on modal analysis, the optimal wide area input signals for the controller are selected. The time delay of input signals, due to electrical distance from the UPFC location is taken into account in the design procedure. The proposed controller is applied to a multimachine interconnected power system from the IRAN power grid. It is shown that the both transient and dynamic stability are significantly improved despite different disturbances and loading conditions.

14

Influence of time delay on fractional-order PI-controlled system for a second-order oscillatory plant model with time delay

Sadalla T., Horla D., Giernacki W., Kozierski P.

Archives of Electrical Engineering

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2017

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Vol. 66, nr 4

693--704

EN

The paper aims at presenting the influence of an open-loop time delay on the stability and tracking performance of a second-order open-loop system and continuoustime fractional-order PI controller. The tuning method of this controller is based on Hermite- Biehler and Pontryagin theorems, and the tracking performance is evaluated on the basis of two integral performance indices, namely IAE and ISE. The paper extends the results and methodology presented in previous work of the authors to analysis of the influence of time delay on the closed-loop system taking its destabilizing properties into account, as well as concerning possible application of the presented results and used models.

15

Determination of the Firing Pin Critical Velocity and the Critical Power in the Percussive Initiation of Primer Caps

Faryński A., Długołęcki A., Dębiński J., Słonkiewicz Ł.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2016

|

Vol. 7, Nr 4 (26)

33--66

EN

This work involved testing of the probability of initiating a KWM-3 type of primer cap as a function of the firing pin velocity upon impact. The tested firing pin was accelerated to the required velocity by a falling mass. The measurements under this work were made with a measurement system and methodologies developed at Air Force Institute of Technology (AFIT) in Warsaw (Poland). The percussive pulse velocity and power was altered by modifying the percussive mass to keep the initiating pulse energy constant at two levels: Ewe = 272 mJ and 343 mJ. The firing pin velocity values estimated by experimental data to bring a 50% probability of percussive primer cap initiation were within the interval vi50% = 0.34÷0.51 m/s. It was found that the mean primer cap ignition delay rose from approx. 0.7 ms at a percussion velocity of 1.5 m/s to 6 ms at 0.17 m/s. The experimental data suggest the values of Ewe × vi50% = 0.136. A simplified model was proposed for the deformation of the primer cap base and compressed pyrotechnical mixture shape. The model served to determine the approximate time trend for the penetration of the primer cap by the firing pin, including velocity, power and emitted energy, by assuming a complete energy transfer from the percussive mass to the primer cap. The mean initiating pulse power calculated from the model at the vi50% interval was Pavg = 120÷180 W, whereas the maximum initiating pulse power was Pmax = 170÷250 W. The calculated time values for firing pin penetration were very close to the aforementioned primer cap ignition delays at the respective velocity and percussive mass values. This indirectly indicates nearly complete energy transmission from the percussive masses to the primer caps. A location was identified within the compressed pyrotechnical mixture shape volume which could form the hot spot for initiation of the explosive reaction. Based on the calculation results using the simplified model, and assuming that the energy and diffusive heat flux output to and from the explosive reaction initiation hot spot were equivalent, the expression of Ewe × vi50% derived from the result was approx. 0.18. This means that the two critical parameters of primer cap initiation: (i) velocity, which can be identified with vi50% (and the respective power) and (ii) Ewe50%, i.e. the energy threshold below which the probability of primer cap initiation is less than 0.5, are interrelated. Aside from the initiation mechanism proposed and applied to calculate the firing pin critical velocity, this work discusses several other initiation mechanisms, all of which were ruled out during the testing process.

PL

W pracy przeprowadzono badania prawdopodobieństwa pobudzenia spłonki typu KWM-3 w funkcji prędkości uderzającej iglicy. Prędkość nadawała iglicy spadająca masa. Pomiary prowadzono za pomocą układu i metod opracowanych w ITWL. Prędkość i moc impulsu uderzeniowego zmieniano poprzez zmianę masy uderzeniowej tak, aby zachować stałość energii impulsu inicjującego na dwóch poziomach: Ewe = 272 mJ i 343 mJ. Oszacowane na podstawie danych doświadczalnych prędkości iglicy, dla których występuje 50% prawdopodobieństwo pobudzenia mieszczą się w przedziale vi50% = 0,34÷0,51 m/s. Stwierdzono, że średnia zwłoka czasowa zadziałania spłonki rosła od ok. 0,7 ms przy prędkości uderzenia wynoszącej 1,5 m/s do 6 ms przy 0,17 m/s. Dane doświadczalne sugerują Ewe × vi50% ≈ 0,136. Zaproponowano uproszczony model deformacji dna spłonki i sprasowanej kształtki mieszaniny pirotechnicznej, za pomocą którego przy założeniu całkowitego przekazania energii spłonce przez masę uderzeniową wyznaczono w sposób przybliżony przebiegi w czasie zagłębiania iglicy w spłonkę i jego prędkości, mocy i wydzielanej energii. Obliczona na podstawie modelu średnia moc w czasie impulsu inicjującego dla podanych vi50% wynosi odpowiednio Pavg = 120÷180 W, natomiast moc maksymalna Pmax = 170÷250 W. Otrzymane w wyniku obliczeń czasy zagłębiania iglicy są bardzo bliskie wyżej wymienionym czasom zadziałania spłonek dla odpowiednich prędkości i mas uderzeniowych, co pośrednio świadczy o niemal całkowitym przekazaniu przez te masy energii spłonkom. Wskazano miejsce w kształtce mieszaniny pirotechnicznej, które może być ogniskiem inicjowania reakcji wybuchu. Na podstawie wyników obliczeń opartych o ten model, przyjmując równość mocy doprowadzania energii i dyfuzyjnego odprowadzenia strumienia ciepła do i z ogniska w temperaturze inicjacji, wyprowadzono wyrażenie na Ewe × vi50% , które dało wartość ok. 0,18. Świadczy to o tym, że dwa parametry krytyczne pobudzenia spłonki – prędkość, którą można utożsamić z vi50% (i odpowiednia moc) oraz Ewe50% – energia, poniżej której prawdopodobieństwo pobudzenia spłonki spada poniżej 0,5, są związane ze sobą. Oprócz mechanizmu pobudzenia zaproponowanego i użytego do obliczenia prędkości krytycznej dyskutowano inne mechanizmy, które wykluczono.

16

Multivariable predictive control considering time delay for load-frequency control in multi-area power systems

Daniar S., Shiroei M., Aazami R.

Archives of Control Sciences

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2016

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Vol. 26, no. 4

527--549

EN

In this paper, a multivariable model based predictive control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area interconnected power system. The proposed controller is designed to consider time delay, generation rate constraint and multivariable nature of the LFC system, simultaneously. A new formulation of the MPC is presented to compensate time delay. The generation rate constraint is considered by employing a constrained MPC and economic allocation of the generation is further guaranteed by an innovative modification in the predictive control objective function. The effectiveness of proposed scheme is verified through time-based simulations on the standard 39-bus test system and the responses are then compared with the proportional-integral controller. The evaluation of the results reveals that the proposed control scheme offers satisfactory performance with fast responses.

17

A time interval generator with the STM32 microcontroller

Sawicki M., Różyc K.

Measurement Automation Monitoring

|

2015

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Vol. 61, No. 7

296--298

EN

The paper presents a concept of utilization of counter-timer circuits built in popular microcontrollers for generating precise time intervals. The main aim was to generate pulses START and STOP wholly in hardware without using a core of the microcontroller. This enables minimizing the value of time jitter of the generated time intervals and allows the use of remaining resources of the microcontroller freely. The introduced method of generation exploits the possibility of simultaneous synchronization of TIM2 and TIM3 timers from an overloaded TIM1 timer. Dependent timers work in One Pulse Mode. START and STOP signals are generated by PWM channels of individual timers. PWM channels can be configured independently which gives the possibility to generate START and STOP pulses of different polarity and width. Generation of a time interval can be triggered automatically (TIM1) or through one of the inputs of the microcontroller. The implemented generator is characterized by the generated range of time interval from 0 to 100 s and the resolution of 40 ns. The jitter of 100 ps was obtained. The concept is suitable to apply in any microcontroller of the STM32 family. It allows the generation of precise and adjustable delays in the application without the need to significantly expand a hardware part of the device.

18

Optimization of information flows of logistic supply chain

Oliskevych M.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2015

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Vol. 4, No 4

71--76

EN

This research is devoted to the problem of information flows of logistic system of goods supplying. Information messages appear at moment of material flows which should be consider as discrete one. It gives an ability to research all changes that can occur to input material flow. Moreover, it makes a possibility to obtain analytic dependence of showers of effectively of system from parameter of information and material flows interaction. Logistic chain was first decomposed on four basic logistic operation such as distributing, unitizing, breaking up, speed up. Three parameters were used to characterize them. All that parameters depend of main flow of goods, packets, transport packets. The principle of solid material flows was applied. Then points of control were defined. It was researched two parts of main problem. First deals with a increasing material flows andconsequences of logistic chain adopting after that. Second deals with an decreasing flow. Control of several ways of different changes of logistic schemas depends of existed information flows which may be sent at one of defined control point. The criteria of material and information flows interaction effectiveness is total time delay per unit. The principle of streamlining is just-in-time. Deviation of appointed moment of operation starting or finishing equals to additional costs. The result consists the dependence of total delay per unit from structure of information flows. It can be used as a condition of real logistic schema optimization.

19

Ionospheric Time-delay over Akure Using Global Positioning System Observations

Bolaji O. S., Izang P. A., Oladosu O. R., Koya F., Fayose R. S., Rabiu A. B.

Acta Geophysica

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2015

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Vol. 63, no. 3

884--899

EN

Ionospheric time delay (VΔt) variability using Global Positioning System (GPS) data over Akure (7.15°N, 5.12°E), Nigeria, has been studied. The observed variability of VΔt in comparison to older results of vertical total electron content (TEC) across similar regions has shown equivalent signatures. Higher monthly mean values of VΔt (MVΔt) were observed during daytime as compared to nighttime (pre- and post- midnight) hours in all months. The highest MVΔt observed in September during daytime hours range between ~6 and ~21 ns (~1.80 and ~6.30 m) and at post-midnight, they are in the range of ~1 to ~6 ns (~0.3 to ~1.80 m). The possible mechanisms responsible for this variability were discussed. Seasonal VΔt were investigated as well.

20

Robust L2 consensus of high-order swarm systems with time-varying delays

Xi J, Yao Z, Liu G., Zhong Y.

Control and Cybernetics

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2014

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Vol. 43, no. 1

59--77

EN

Consensus problems for high-order continuous-time swarm systems in directed networks with time delays, uncertainties and external disturbances are investigated. Firstly, the state space of a swarm system is decomposed into a consensus subspace (CS) and a complement consensus space (CCS). A necessary and sufficient condition for the system with time delays and uncertainties to achieve consensus is presented based on the state projection on CCS, and an explicit expression of the consensus function is shown on the basis of the state projection on CS. Then, a sufficient condition for the system to achieve consensus with a desired L2 performance is given. Finally, numerical simulations are shown to demonstrate theoretical results.