Добірка наукової літератури з теми "Relative puese duration of the control signal"

Introduction: When diagnosing the deviations of controllable dynamic system parameters, it is convenient in terms of control simplicity to apply the Schreiber method which uses a set of rectangular pulses of equal duration as a test signal. Since for a single object you can construct many test signals which differ in the number of pulses, the problem arises how to minimize the number of test pulses when using the Schreiber method. Purpose: Simplification of test control and diagnostics of linear controllable dynamic systems. Results: It has been shown that a set of test pulse amplitude vectors is a kernel of the controllability matrix of a discrete analogue of the object under test. The problem is formulated of finding the optimal length of a test pulse in order to minimize the number of pulses in the test signal. For a given pulse length, the pulse amplitudes of an optimal test signal are equal to the coefficients of the control vector minimal polynomial for the discrete analog of the object relative to its system matrix. The number of test pulses can be reduced by choosing the pulse duration calculated from the imaginary component of the object poles. In particular, if an object has at least one pair of complex-conjugate poles, the number of test pulses does not at least exceed the order of the object. An algorithm has been developed for calculating a test signal for linear controllable object FDI by the Schreiber method. The input to the algorithm is the system matrix of the object, and the output is the length of the test pulse and the pulse amplitude vector. The efficiency of the algorithm is illustrated by FDI for two technical objects. Practical relevance: The results of the study can be applied to static parameter FDI of controllable dynamical objects which allow a linear description in their state space.

A stable 50-mJ three-channel optical waveform synthesizer is demonstrated and used to reproducibly generate a high-order harmonic supercontinuum in the soft x-ray region. This synthesizer is composed of pump pulses from a 10-Hz repetition-rate Ti:sapphire pump laser and signal and idler pulses from an infrared two-stage optical parametric amplifier driven by this pump laser. With full active stabilization of all relative time delays, relative phases, and the carrier-envelope phase, a shot-to-shot stable intense continuum harmonic spectrum is obtained around 60 eV with pulse energy above 0.24 μJ. The peak power of the soft x-ray continuum is evaluated to be beyond 1 GW with a 170-as transform limit duration. We found a characteristic delay dependence of the multicycle waveform synthesizer and established its control scheme. Compared with the one-color case, we experimentally observe an enhancement of the cutoff spectrum intensity by one to two orders of magnitude using three-color waveform synthesis.

Electropneumatic valves are a key element of the electropneumatic clutch control system for vehicles of categories N3 and M3. The speed and accuracy of the clutch control system depend on their parameters. When the operating conditions of the solenoid valve change, its initial parameters also change, even before the loss of serviceability. Goal. The goal of the work is to form dependencies that determine the parameters of the control signal for the clutch control system of vehicles of categories M3 and N3 in the conditions of change of supply voltage, pressure drop on the valve and ambient temperature. Methodology. To achieve this goal, an advanced mathematical model and onedimensional optimization method were used to determine the optimal control effect on the electropneumatic valve of the clutch control system. Results. The block diagram of the control pulse in different modes of operation of the electropneumatic clutch control system is given. Based on the calculated data, the characteristic areas of operation of the electropneumatic valve are determined and the purpose for the optimization process is determined. Based on the defined range of data change and the accuracy of finding the optimal value, a rational optimization method is determined. By modeling the operation of the solenoid valve with parameters according to the chosen optimization method, the response surfaces were constructed relative to the control pulse depending on such parameters as supply voltage of the vehicle onboard network, ambient temperature and pressure drop on the solenoid valve. Originality. The error in the reproduction of the theoretical response surfaces based on the parameters of the clutch and the electronic control unit is also determined. Theoretical aspects for providing the required inductance of the solenoid valve coil are shown. Practical value. A method for determining the pressure drop on an electropneumatic valve is proposed. The method takes into account the change in pressure during operation of the clutch control system due to wear of the friction plate. The error in ensuring the duration of the control pulse due to the presence of hysteresis in the operation of the clutch and the executive control device is estimated.

In below-grade buildings and buried structures, such as those constructed as hardened secure facilities and used for munitions storage on U.S. Army installations, water intrusion can cause serious damage and reduce penetration resistance. Inside the building active water and high humidity can result in corrosion of HVAC, electronic equipment, as well as damage or disrupt mission critical electronic equipment. In the adjacent backfill and the structure itself, excessive water can seriously compromise the structural hardening of the facility. Thus, it is vital to Army sustainability to control moisture in below-grade structures and eliminate corrosion of electrical mechanical equipment. This also prevents mold growth on the interior surface of below grade concrete walls and floors. Control of water movement involves both actively removing water in and around a building, and the use of barriers to prevent water from penetrating to interior spaces. A pumping system is typically required with the use of a barrier system to assist in controlling the movement of moisture into the structure. Conventional waterproofing technologies are expensive and often have short service life. A new approach is needed—a cost effective and robust solution—to the pervasive problem of water intrusion. Electro-Osmotic Pulse is a promising alternative solution presented here. Electro-Osmotic Pulse (EOP) technology uses pulses of electricity to reverse the flow of water seepage. The applied voltage causes moisture to flow out of the basement walls and away from the building. The technology works by alternately pulsating a direct electric field with an off period. The first part of the sequence consists of a pulse of positive voltage (as seen from the dry side of the concrete wall), followed by a pulse of negative voltage. This is followed by a period when no voltage is applied. Of the three parts, the positive voltage pulse has the greatest time duration. The amplitude of the positive signal is typically on the order of 20 to 40 Volts DC. This electrical pulse causes cations (e.g., Ca++) and associated water molecules to move from the dry side (anode) towards the wet side (cathode) against the direction of flow induced by the hydraulic gradient, thus preventing water penetration through buried concrete structures. Laboratory and field tests have shown an increase in calcium compounds at the cathode side of test specimens. The negative portion of the pulse increases the efficiency of moisture movement by depolarizing the electrodes. Electro-Osmotic Pulse (EOP) technology has been successfully installed in military structures such as family housing, steel reinforced deep structures, and tunnels. EOP has also been implemented on Civilian structures such as residential structures, D.C. Metro Tunnels, and an underground treasury vault. EOP has been shown to prevent moisture seepage into below-grade structures. It is effective at keeping concrete surfaces at or below 50 percent humidity content, meaning the treated space stays dry, indoor relative humidity stays low, and no mold or mildew can grow. This technology has received the 2002 international NOVA award for innovation in construction, and twice nominated for the CERF Pankow award (1999 and 2004). The ERDC research on this technology has also been recognized by the 2004 Army Research and Development Achievement Award.

Abstract In this paper, we study the diagnostics and identification of injection duration of common rail (CR) diesel pilot injectors of dual-fuel engines. In these pilot injectors, the injected volume is small and the repeatability of the injections and identification of the drifts of the injectors are important factors, which need to be taken into account in achieving good repeatability (shot-to-shot with every cylinder) and therefore a well-balanced engine and reduced overall wear. A diagnostics method based on analysis of CR pressure signal with experimental verification results is presented. Using the developed method, the relative duration of injection events can be identified. In the method, the pressure signal during the injection is first extracted after the control of each injection event. After that, the signal is normalized and filtered. Then a derivative of the filtered signal is calculated. Change in the derivative of the filtered signal larger than a predefined threshold indicates an injection event which can be detected and its relative duration can be identified. The efficacy of the proposed diagnostics method is presented with the experimental results, which show that the developed method detects drifts in injection duration and the magnitude of drift. According to the result, ≥ 10 μs change (2%, 500 μs) in injection time can be identified.

Electromyographic (EMG) and kinematic data were collected from European starlings (Sturnus vulgaris) flying at a range of speeds from 8 to 18 m s-1 in a variable-speed windtunnel. Their flight at all speeds consisted of alternating flapping and non-flapping phases. Wing postures during non-flapping phases included glides, partial-bounds and bounds. Glides were performed proportionally more often within each speed and were longer in duration than either of the other two non-flapping postures, but the percentage of bounds increased markedly with increasing flight speed. The shift from flap-gliding at slow speeds towards flap-bounding at fast speeds was consistent with reducing mean power output relative to continuous flapping. The starlings often combined more than one non-flapping posture within a single non-flapping period. Transitions between non-flapping postures, as well as transitions between bounds and subsequent flapping, were classified as 'pull-outs'. Pull-outs consisted of an increase in wingspan but no change in wingtip elevation. The pectoralis and supracoracoideus exhibited electrical activity during glides but not during bounds. The scapulohumeralis caudalis was not active during glides, but this muscle and the supracoracoideus were typically active during partial-bounds and pull-out phases. The scapulohumeralis caudalis occasionally showed activity during bounds, which may reflect its role as a humeral retractor. The frequency and duration of non-flapping intervals in starlings were less during EMG experiments than during non-implanted flights. During flapping phases, relative intensity and duration of EMG signal and wingbeat frequency increased with flight speed, whereas flapping or non-flapping cycle duration, the percentage of a cycle spent flapping and the number of wingbeats in a cycle were all greatest at 8 m s-1. Wingbeat amplitude was smaller at intermediate speeds, but differences among speeds were not significant. These variables allowed indirect estimates of power output and suggested that minimum power speed for starlings was near 12 m s-1 and that power output increased at both slower and faster speeds. Within windtunnel speeds, muscle activity changed in relation to wingspan at mid-upstroke, wingtip excursion, wingbeat frequency, acceleration, velocity, altitude and horizontal position.

Oximeters used for continuous monitoring experience periods with no signal. This SpO2drop-out is widely acknowledged and its causes generally understood. This is a prospectively designed analysis of an existing database with the aim of characterizing drop-outs as experienced in the neonatal ICU. The data reflects 116 days of monitoring in seven tertiary care neonatal ICUs in 6 countries. From the evaluation of 1,396 drop-outs we found that typically the time was minimal with missing SpO2 data, and the episodes were short (median 2.79 minutes per day IQR 0.17-76, median 22 seconds IQR: 15-37, respectively). During during about half of the days there were no prolonged dropouts (1 minute or longer), even so half of the total time spent with no SpO2data were in prolonged episodes (median length 110 seconds IQR 85-150). The predominate factor associated with excessive drop-out time was the number of prolonged episodes rather than their duration. We concluded that the impact of drop-outs during manual control of inspired oxygen primarily impact alarm fatigue, but that during automatic FiO2control they could have an important impact. The relative effectiveness of the fall-back strategies of these automatic control systems ought to be evaluated.

Understanding how orofacial muscle activity and movement covary across changes in speech rate and intensity has implications for the neural control of speech production and the use of clinical procedures that manipulate speech prosody. The present study involved a correlation analysis relating average lower-lip and jaw-muscle activity to lip and jaw movement distance, speed, and duration. Recordings were obtained on orofacial movement, muscle activity, and the acoustic signal in 3 normal speakers as they repeated a simple test utterance with targeted speech rates varying from 60% to 160% of their habitual rate and at targeted vocal intensities of –6 dB and +6 dB relative to their habitual intensity. Surface electromyographic (EMG) recordings were obtained with electrodes positioned to sample primarily the mentalis, depressor labii inferior, anterior belly of the digastric, and masseter muscles. Two-dimensional displacements of the lower lip and jaw in the midsagittal plane were recorded with an electromagnetic system. All participants produced linear changes in percent utterance duration relative to the auditory targets for speech rate variation. Intensity variations ranged from –10 dB to +8 dB. Average EMG levels for all 4 muscles were well correlated with specific parameters of movement. Across the intensity conditions, EMG level was positively correlated with movement speed and distance in all participants. Across the rate conditions, EMG level was negatively correlated with movement duration in all participants, while greater interparticipant variability was noted for correlations relating EMG to speed and distance. For intensity control, it is suggested that converging neural input to orofacial motoneurons varies monotonically with movement distance and speed. In contrast, rate control appears to be more strongly related to the temporal characteristics of neural input than activation level.

AbstractIntroductionHaemodynamically unstable patients can experience potentially hazardous changes in vital signs related to the exchange of depleted syringes of epinephrine to full syringes. The purpose was to determine the measured effects of epinephrine syringe exchanges on the magnitude, duration, and frequency of haemodynamic disturbances in the hour after an exchange event (study) relative to the hours before (control).Materials and methodsBeat-to-beat vital signs recorded every 2 seconds from bedside monitors for patients admitted to the paediatric cardiovascular ICU of Texas Children’s Hospital were collected between 1 January, 2013 and 30 June, 2015. Epinephrine syringe exchanges without dose/flow change were obtained from electronic records. Time, magnitude, and duration of changes in systolic blood pressure and heart rate were characterised using Matlab. Significant haemodynamic events were identified and compared with control data.ResultsIn all, 1042 syringe exchange events were found and 850 (81.6%) had uncorrupted data for analysis. A total of 744 (87.5%) exchanges had at least 1 associated haemodynamic perturbation including 2958 systolic blood pressure and 1747 heart-rate changes. Heart-rate perturbations occurred 37% before exchange and 63% after exchange, and 37% of systolic blood pressure perturbations happened before syringe exchange, whereas 63% occurred after syringe exchange with significant differences found in systolic blood pressure frequency (p<0.001), duration (p<0.001), and amplitude (p<0.001) compared with control data.ConclusionsThis novel data collection and signal processing analysis showed a significant increase in frequency, duration, and magnitude of systolic blood pressure perturbations surrounding epinephrine syringe exchange events.

We consider the task of automated quality control of sound recordings containing voice samples of individuals. It is shown that in this task the most acute is the small sample size. In order to overcome this problem, we propose the novel method of acoustic measurements based on relative stability of the pitch frequency within a voice sample of short duration. An example of its practical implementation using aninter-periodic accumulation of a speech signal is considered. An experimental study with specially developed software provides statistical estimates of the effectiveness of the proposed method in noisy environments. It is shown that this method rejects the audio recording as unsuitable for a voice biometric identification with a probability of 0,95 or more for a signal to noise ratio below 15 dB. The obtained results are intended for use in the development of new and modifying existing systems of collecting and automated quality control of biometric personal data. The article is intended for a wide range of specialists in the field of acoustic measurements and digital processing of speech signals, as well as for practitioners who organize the work of authorized organizations in preparing for registration samples of biometric personal data.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. Національний технічний університет "Харківський політехнічний інститут". – Харків, 2017. З метою розширення області застосування АБС за рахунок зниження вартості модулятора тиску досліджено процес осциляційної модуляції тиску. Запропоновано конструкцію осциляційного модулятора, який задовольняє всі висунуті до нього вимоги, та доведено можливість його застосування в якості виконавчого елемента у складі дуальних адаптивних гальмівних системах. Порівняльний аналіз відомих способів модуляції тиску в гідравлічному гальмівному приводі показав, що тільки спосіб осциляційної модуляції не вимагає для своєї реалізації дорогих конструктивних елементів (електромагнітних клапанів, насосів, що підкачують, крокових електродвигунів і т.п.), що дозволяє знизити вартість модуляторів при їх застосуванні. Моделювання процесу осциляційної модуляції та лабораторні випробування осциляційного модулятора показали: – принципову можливість осциляційної модуляції у всьому необхідному діапазоні зміни тиску від 0 до 10 МПа; – працездатність запропонованої конструкції модулятора і його відповідність усім пред’явленим до модулятору АБС вимогам. Дослідження роботи осциляційного модулятора у складі дуальної адаптивної гальмівної системи, виконані шляхом моделювання процесу гальмування автомобіля при різних станах дорожньої поверхні та режимах руху підтвердили, що застосування осциляційного модулятора не погіршують показники ефективності гальмування, стійкості і керованості у порівнянні з відомими.
The dissertation on competition of a scientific degree of candidate of technical sciences, speciality 05.22.02 – cars and tractors. National technical university "Kharkiv polytechnic institute". – Kharkiv, 2017. With the of expanding the field of application of anti-block system by reducing the value of the pressure modulator investigated the process of the oscillating modulation of the pressure. The proposed design of the oscillating modulator that meets all applicable requirements and proved the possibility of its use as an clement in the composition of the dual adaptive brake systems. Comparative analysis of the known methods of modulation of the pressure in the hydraulic brake drive showed that the only way of oscillating modulation does not require expensive structural elements (solenoid valves, booster pumps, stepper motors, etc.) that can reduce the cost of modulators in its application. Modeling of oscillating modulation process and laboratory tests of oscillating modulator showed: – principle possibility of oscillating modulation in all the required range of pressure changes from 0 to 10 МПА; – the efficiency of the proposed design of the modulator and its compliance with all requirements to the anti-block system modulator. Research work of oscillating modulator comprising a dual adaptive brake system, made by modeling the process of deceleration of the vehicle under different conditions of road surface and driving conditions confirmed that the application of an oscillating modulator does not degrade the braking efficiency, stability and controllability with the known.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. Національний технічний університет "Харківський політехнічний інститут". – Харків, 2017. З метою розширення області застосування АБС за рахунок зниження вартості модулятора тиску досліджено процес осциляційної модуляції тиску. Запропоновано конструкцію осциляційного модулятора, який задовольняє всі висунуті до нього вимоги, та доведено можливість його застосування в якості виконавчого елемента у складі дуальних адаптивних гальмівних системах. Порівняльний аналіз відомих способів модуляції тиску в гідравлічному гальмівному приводі показав, що тільки спосіб осциляційної модуляції не вимагає для своєї реалізації дорогих конструктивних елементів (електромагнітних клапанів, насосів, що підкачують, крокових електродвигунів і т.п.), що дозволяє знизити вартість модуляторів при їх застосуванні. Моделювання процесу осциляційної модуляції та лабораторні випробування осциляційного модулятора показали: – принципову можливість осциляційної модуляції у всьому необхідному діапазоні зміни тиску від 0 до 10 МПа; – працездатність запропонованої конструкції модулятора і його відповідність усім пред’явленим до модулятору АБС вимогам. Дослідження роботи осциляційного модулятора у складі дуальної адаптивної гальмівної системи, виконані шляхом моделювання процесу гальмування автомобіля при різних станах дорожньої поверхні та режимах руху підтвердили, що застосування осциляційного модулятора не погіршують показники ефективності гальмування, стійкості і керованості у порівнянні з відомими.
The dissertation on competition of a scientific degree of candidate of technical sciences, speciality 05.22.02 – cars and tractors. National technical university "Kharkiv polytechnic institute". – Kharkiv, 2017. With the of expanding the field of application of anti-block system by reducing the value of the pressure modulator investigated the process of the oscillating modulation of the pressure. The proposed design of the oscillating modulator that meets all applicable requirements and proved the possibility of its use as an clement in the composition of the dual adaptive brake systems. Comparative analysis of the known methods of modulation of the pressure in the hydraulic brake drive showed that the only way of oscillating modulation does not require expensive structural elements (solenoid valves, booster pumps, stepper motors, etc.) that can reduce the cost of modulators in its application. Modeling of oscillating modulation process and laboratory tests of oscillating modulator showed: – principle possibility of oscillating modulation in all the required range of pressure changes from 0 to 10 МПА; – the efficiency of the proposed design of the modulator and its compliance with all requirements to the anti-block system modulator. Research work of oscillating modulator comprising a dual adaptive brake system, made by modeling the process of deceleration of the vehicle under different conditions of road surface and driving conditions confirmed that the application of an oscillating modulator does not degrade the braking efficiency, stability and controllability with the known.