Therapeutic Validation of Venous Pulsatile Tinnitus and Biomaterial Applications for Temporal Bone Reconstruction Surgery Using Multi-sensing Platforms and Coupled Computational Techniques

The application of grafts and biomaterials is a cardinal therapeutic procedure to resolve venous pulsatile tinnitus (PT) caused by temporal bone dehiscence during transtemporal reconstructive surgery. However, the transmission mechanism of venous PT remains unclear, and the sound absorption and insulation properties of different repair materials have not been specified. This study quantifies the vibroacoustic characteristics of PT, sources the major transmission pathway of PT, and verifies the therapeutic effect of different material applications using joint multi-sensing platforms and coupled computational fluid dynamics (CFD) techniques. The in vivo intraoperative acoustic and vibroacoustic characteristics of intrasinus blood flow motion and dehiscent sigmoid plate of a typical venous PT patient were investigated using acoustic and displacement sensors. The acoustical, morphological, and mechanical properties of the dehiscent sigmoid plate, grafts harvested from a cadaveric head, and other biomaterials were acquired using acoustical impedance tubes, micro-CT, scanning electron microscopy, and mercury porosimetry, as appropriate. To analyze the therapeutic effect of our previous reconstructive techniques, coupled CFD simulations were performed using the acquired mechanical properties of biomaterials and patient-specific radiologic data. The peak in vivo intraoperatively gauged, peak simulated vibroacoustic and peak simulated hydroacoustic amplitude of PT prior to sigmoid plate reconstruction were 64.0, 70.4, and 72.8 dB, respectively. After the solidified gelatin sponge–bone wax repair technique, the intraoperative gauged peak amplitude of PT was reduced from 64.0 to 47.3 dB. Among three different reconstructive techniques based on CFD results, the vibroacoustic and hydroacoustic sounds were reduced to 65.9 and 68.6 dB (temporalis–cartilage technique), 63.5 and 63.1 dB (solidified gelatin sponge technique), and 42.4 and 39.2 dB (solidified gelatin sponge–bone wax technique). In conclusion, the current novel biosensing applications and coupled CFD techniques indicate that the sensation of PT correlates with the motion and impact from venous flow, causing vibroacoustic and hydroacoustic sources that transmit via the air-conduction transmission pathway. The transtemporal reconstructive surgical efficacy depends on the established areal density of applied grafts and/or biomaterials, in which the total transmission loss of PT should surpass the amplitude of the measured loudness of PT.

ANALYSIS OF THE capabilities OF the CLOSED-OPEN SYSTEM CORRECTION scheme FOR MEASURING VIBRATIONS OF AIRCRAFT STRUCTURal ELEMENTS

В настоящее время в связи со всевозрастающей степенью сложности проектирования, производства и эксплуатации летательных аппаратов все более важным направлением в области развития информационно-измерительных систем становится совершенствование существующих и разработка новых способов измерения параметров вибрации элементов механических конструкций летательных аппаратов. Целью данной работы является анализ возможности и перспективности построения системы для измерения вибраций элементов конструкции самолета на основе использования микромеханических инерциальных измерительных блоков в качестве основных виброметрических измерителей. При этом объектом исследования является система измерения параметров вибрации, а предметом – ее структура, состав, алгоритмы функционирования и ожидаемые точностные характеристики. Для достижения поставленной цели строится информационно-измерительная система на базе инерциальных приборов, а также датчиков для непосредственных измерений перемещений, используются численные и аналитические методы высшей математики и теоретической механики, методы теории случайных процессов и оптимального оценивания. В статье рассмотрены принципы построения такой системы на примере варианта системы измерения параметров вибраций крыла самолета, представлен краткий обзор существующих решений в предметной области и обоснована актуальность и целесообразность предложенного варианта технического решения. Приведены базовый состав и структура системы, описаны основные принципы ее работы, основанные на использовании данных датчиков перемещения, инерциальных измерителей и оптимального калмановского оценивания и коррекции. Показаны основные алгоритмы работы системы, включая алгоритмы ориентации и навигации, оценивания и коррекции при замкнуто-разомкнутой схеме включения оптимального фильтра Калмана, алгоритм вычисления параметров вибрации, представленыматематические модели ошибок основных измерителей системы, показаны полученные предварительные результаты имитационного моделирования, демонстрирующие работоспособность системы и ее ожидаемые приемлемые точностные характеристики, подтверждающие возможность эффективного использования системы и перспективность выбранного направления работ. At present, because of the ever-increasing degree of complexity of aircrafts design, production and operation, the improvement of the existing methods and development of new ones for vibration parameters measurement of aircrafts mechanical structural elements is still an important direction in the field of information-measurement systems development. The purpose of this work is to analyze the possibility and prospects of constructing a system for measuring vibrations of aircraft structural elements based on the use of micromechanical inertial measurement units as the main vibrometric transducers. In this case, the object of research is the vibration parameters measurement system, and the subject is its structure, composition, operations algorithms and the expected accuracy characteristics. To achieve this purpose, an information-measurement system is built on the basis of inertial devices, as well as sensors for direct displacements measurements, numerical and analytical methods of higher mathematics and theoretical mechanics, methods of random processes theory and optimal estimation are used. The article discusses the principles of constructing such system taking as an example a system for measuring the vibration parameters of an aircraft wing, provides a brief overview of the existing solutions in this field of applications and substantiates the relevance and expediency of the proposed methodology of the technical solution. The basic components and structure of the system are presented, the basic principles of its operation are described, based on the use of data from displacement sensors, inertial meters and optimal Kalman estimation and correction. The main algorithms of the system operation are shown, including the orientation and navigation algorithm, estimation and correction algorithm for a closed-open scheme of optimal Kalman filter inclusion in the system, algorithm for calculating vibration parameters, beside the mathematical errors models of the main system sensors and channels are presented, preliminary results of simulation modeling are shown and they demonstrate the operability of the system and its expected acceptable accuracy characteristics, confirming the possibility of the effective use of the proposed system and the prospects of the chosen direction of work.

Soft Robotic Sensing, Proprioception via Cable and Microfluidic Transmission

Current challenges in soft robotics include sensing and state awareness. Modern soft robotic systems require many more sensors than traditional robots to estimate pose and contact forces. Existing soft sensors include resistive, conductive, optical, and capacitive sensing, with each sensor requiring electronic circuitry and connection to a dedicated line to a data acquisition system, creating a rapidly increasing burden as the number of sensors increases. We demonstrate a network of fiber-based displacement sensors to measure robot state (bend, twist, elongation) and two microfluidic pressure sensors to measure overall and local pressures. These passive sensors transmit information from a soft robot to a nearby display assembly, where a digital camera records displacement and pressure data. We present a configuration in which one camera tracks 11 sensors consisting of nine fiber-based displacement sensors and two microfluidic pressure sensors, eliminating the need for an array of electronic sensors throughout the robot. Finally, we present a Cephalopod-chromatophore-inspired color cell pressure sensor. While these techniques can be used in a variety of soft robot devices, we present fiber and fluid sensing on an elastomeric finger. These techniques are widely suitable for state estimation in the soft robotics field and will allow future progress toward robust, low-cost, real-time control of soft robots. This increased state awareness is necessary for robots to interact with humans, potentially the greatest benefit of the emerging soft robotics field.

RESULTS OF STATIC TESTS OF PROTECTIVE STRUCTURES OF AGRICULTURAL TRACTORS CABINS

The purpose of research is determination of cabin deformation indicators using standardized methods and developed technical means. Research methods. The tests were performed according to the methods described in [DSTU ISO 5700, 2019] using a loading bench, pressure and displacement sensors, digital measuring amplifier Spider 8 and laptop Panasonic CF-19 Touchbook, model: CF-19KHR88PE. Research results. The protective structure AI.209.45.011.00 of the cab of tractors type C25 "Slobozhanets" was provided for testing. Before the tests, the dimensions of the cab structure were measured and recorded. During the first longitudinal loading from front to right, the load was applied to the upper transverse element of the protective structure. The point of application of the load was at a distance of 260 mm from the outer corner of the edge of the protective structure. An even load distribution in the direction perpendicular to the direction of action and along the loading beam was ensured using a sealing element. The value of the energy absorbed by the protective structure was 13100 J (required energy - 12586 J) with a maximum applied force of 82 kN and a displacement of 340 mm. During the first and second compression tests, the structure was loaded vertically with a force of 180 kN along the front and rear upper transverse elements of the protective structure with a holding of the specified force for 5 s. The side load was applied horizontally to the upper right longitudinal element of the protective structure at a distance of 85 mm forward from the control point of the driver's seat. The length of the loading beam was 600 mm. The value of the energy absorbed by the protective structure of 17000 J (required energy - 15732 J) at a maximum applied force of 80 kN and a displacement of 290 mm was achieved. After all test stages, the frontmost point of the protective structure was 70 mm and the front left point was 35 mm. The rear end points were also shifted backwards by 45 mm - right and 30 mm - left. In the lateral direction, the front right extreme point moved forward by 15 mm. After the tests, the free space area was not violated. Conclusions. The methods and technical means used during the tests allow determine the magnitude of the applied forces and deformation with the necessary accuracy and reliability. During the compression tests, the values of the test force (180 kN) were achieved, and during the application of horizontal loads - the energy absorbed by the protective structure (13100 J - longitudinal load and 17000 J - lateral load). The greatest final deformation was suffered by the protective structure at the front extreme point - 70 mm, while the violation of the zone of free space of the driver by the elements of the protective structure is not observed. Therefore, the protective structure AI.209.45.011.00 cab of tractors type C25 "Slobozhanets" withstood static tests for compliance with DSTU ISO 5700.

A novel piezoelectric-actuated microgripper simultaneously integrated microassembly force, gripping force and jaw-displacement sensors: design, simulation and experimental investigation

For assembling easy-to-deform and easy-to-broken micropart, accurate acquisition of microassembly force and gripping force during microassembly process while ensuring parallel movement of jaws of microgripper is the key to ensure consistency, accuracy and reliability of microassembly without damage. In addition, simultaneously real-time detection of jaw-displacement of microgripper is also a necessary condition for rapid and accurate microassembly. This paper proposes and realizes a principle of a parallelogram compliant mechanism (PCM) based piezoelectric-actuated microgripper, which simultaneously integrates with microassembly force, gripping force and jaw-displacement sensors for the first time and ensures parallel movement of jaws under no-load and gripping micropart. The major structure of proposed microgripper is a monolithic compliant mechanism (MCM) composed of a primary lever compliant mechanism and three-stage PCM in series. Among them, the third-stage PCM is orthogonal to other two PCM in series. MCM transmits the displacement and force from piezoelectric actuator to jaws while transforming microassembly force, gripping force and jaw-displacement into surface strain of single-notch hinges of PCM with three-stage in series. On this basis, simultaneously sensing microassembly force, gripping force and jaw-displacement is realized by monitoring surface strain of single-notch hinges of three-stage PCM. The sensing equations of the microassembly force, gripping force, and jaw-displacement are established, respectively. A microgripper is manufactured, a microgripper system is realized and the integrated sensors are calibrated. The hysteresis characteristics, creep characteristics and time response are tested experimentally. Two examples of microassembly sub-process are simulated and carried out on the constructed microassembly experimental setup. The theoretical and experimental results show that the designed microgripper can simultaneously acquire the microassembly force, gripping force and jaw-displacement with high sensitivity, linearity and resolution in processes of gripping hohlraum and applying microassembly force to hohlraum while ensuring the parallel movement of the gripping jaws when gripping and not gripping micropart.

Experimental research on cage motion with different pocket shapes in angular contact ball bearing

The cage motion with different pocket shapes, such as spherical, square, and cylindrical, in an angular contact ball bearing under different operating conditions are studied experimentally. A test rig with two laser displacement sensors is used to obtain the displacements of the cage in five freedom degrees. The results reveal that these three type cage shapes have different trends of the centroid trajectory versus rotating speed or radial load. The whirling radius is equal to half of the pocket clearance for the spherical pocket, and half of the guiding clearance for both square and cylindrical pocket. The slip rates of all cages decrease with increasing radial load, and increase with rotating speed. Both inclination angel and slip rate of the spherical, cylindrical and square pocket decrease in turn.

Three-Probe Error Separation with Chromatic Confocal Sensors for Roundness Measurement

In this study, three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement. Here, the harmonic suppression is discussed first to set suitable orientation angles among three sensors. Monte Carlo simulation is utilized to test the error separation and optimize the orientation angles and off-axial distance. The experimental setup is established using chromatic confocal sensors with a precise rotary platform. The experimental results show that the measured roundness with an orientation-angle combination of (0°, 90.1°, and 178.6°) is much better than that of another nonoptimal selection (0°, 90.4°, and 177.4°). The roundness error is only 0.7% between the proposed measurement system and an expensive ultraprecision roundness meter. Furthermore, it is proven that the eccentricity distance should be decreased as small as possible to improve the measurement accuracy. In sum, this paper proposes a feasible method for roundness measurement with reliable simulations, easily integrated sensors, and an ordinary precision rotary platform.

Displacement Sensing of an Active String Actuator by an Optical Fiber

We have fabricated a string-shaped actuator called “Active string” that has high contractile displacement/force by accumulating thin pneumatic artificial muscles using the string production process. However, displacement control of the active string is challenging because general bulky and rigid displacement sensors are not suitable for the sensor element of the active string. Therefore, in this report, a flexible optical fiber sensor is combined with the active string to enable sensing of its displacement. As the active string contracts, the radius of curvature of the optical fiber decreases, and light intensity propagating in the optical fiber decreases due to bending loss. The experimental results showed that the optical fiber sensor value changed with corresponding to the displacement of the active string. It shows the possibility that it is possible to make a displacement estimation of the displacement of the active string using an optical fiber sensor.