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Статті в журналах з теми "Threshold acceleration sensor"
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Feng, Jiacheng, Jun Ma, ZaiYan Gong, Di Kang, and Chao Wang. "Design of Multi-threshold Acceleration Switch Based on Matlab." MATEC Web of Conferences 232 (2018): 04026. http://dx.doi.org/10.1051/matecconf/201823204026.
Повний текст джерелаАнотація:
Acceleration switch can trigger switches according to the variation of external acceleration without complex control system and circuit. With the excellent characteristics of integration of sensor and actuator, zero power consumption and high reliability, multi-threshold acceleration switch has great application value in the fields of vehicle safety, aerospace and industrial equipment. In order to reduce the complexity of the measurement system and improve the reliability, we realized the design of a multi-threshold and anti-overloading acceleration switch which can distinguish specific pulse width. Additionally, the magnetic elastic contact is designed to prevent the rebound phenomenon when switch is overloaded. Considering the coupling force of spring, magnetic elastic contact and magnetic, we built the dynamic model and analysed the influence of the acceleration threshold and the pulse width on the switch actuation. The numerical simulation shows that the proposed switch has accurate sensitivity of acceleration excitation with specific threshold and certain pulse width, and it also has the ability of anti-overload. Consequently, the proposed method provides a new method for designing acceleration switch.
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Liu, Min, Xinyang Wu, Yanxu Niu, Haotian Yang, Yingmin Zhu, and Weidong Wang. "Research Progress of MEMS Inertial Switches." Micromachines 13, no. 3 (February 24, 2022): 359. http://dx.doi.org/10.3390/mi13030359.
Повний текст джерелаАнотація:
As a typical type of MEMS acceleration sensor, the inertial switch can alter its on-off state while the environmental accelerations satisfy threshold value. An exhaustive summary of the design concept, performance aspects, and fabrication methods of the micro electromechanical system (MEMS) inertial switch is provided. Different MEMS inertial switch studies were reviewed that emphasized acceleration directional and threshold sensitivity, contact characteristics, and their superiorities and disadvantages. Furthermore, the specific fabrication methods offer an applicability reference for the preparation process for the designed inertial switch, including non-silicon surface micromachining technology, standard silicon micromachining technology, and the special fabrication method for the liquid inertial switch. At the end, the main conclusions of the current challenges and prospects about MEMS inertial switches are drawn to assist with the development of research in the field of future engineering applications.
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Yu, Yudan, Wei Lin, and Zhaoyang Yu. "Research on motion track error detection and compensation algorithm based on MEMS sensor." ITM Web of Conferences 47 (2022): 02010. http://dx.doi.org/10.1051/itmconf/20224702010.
Повний текст джерелаАнотація:
Due to various errors in actual use, MEMS inertial sensors have large errors in the detection of motion trajectories. Therefore, it is necessary to analyse and model the errors to decrease the impact of error sources on the detection system. This errors mainly include systematic random errors and accumulated errors generated during double integral operation, and different filtering methods are used for different types of errors. For random errors, the wavelet fuzzy threshold method is used to filter the sensor output signal. For the accumulated error, the zero-state adaptive compensation algorithm is used to correct the acceleration and integral velocity. Experiments show that the wavelet threshold denoising algorithm combined with the zero-state adaptive compensation algorithm can enhance the preciseness of the MEMS inertial sensor in object trajectory detection.
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Tian, Wen Chao, Ya Feng Hao, and Hong Fang Ruan. "Simulation and Test of Bistable Inductive Micro-Switch." Advanced Materials Research 230-232 (May 2011): 779–83. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.779.
Повний текст джерелаАнотація:
Inductive micro-switch is an integrative device of a sensor and actuator. It can not only induce an external acceleration, but can also be controlled by the external acceleration to realize the trigger action. However, its malfunctions related to “fail-to-closure” and “transient-closure” result in low reliability and weak anti-jamming capability. A new bistable inductive micro-switch is presented based on micro size adhesive effect. The dynamic simulation is obtained by Comsol software. The simulation shows the threshold acceleration is 23.6g, and the response time is 0.38ms. The micro-switch is tested by a centrifuge. The test result shows that the threshold acceleration is 24g.The relative error between the theoretical analysis and the test result is only 1.6%.
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Norhabibah, Siti, Wahyu Andhyka, and Diah Risqiwati. "Rancang Bangun Sistem Monitoring Deteksi Jatuh untuk Manula dengan Menggunakan Accelerometer." JOINCS (Journal of Informatics, Network, and Computer Science) 1, no. 1 (July 21, 2017): 43. http://dx.doi.org/10.21070/joincs.v1i1.803.
Повний текст джерелаАнотація:
Elderly is a last transitional period of human life. Decrease or disappearance of organ function such as loss of balance, reduced vision and hearing cause the elderly often fall. The limited physical ability of them requires supervision. Supervision is necessary to avoid undesirable thing occurs. Here, a tool called accelerometer can be used to supervise and monitor whether the fall incident occurs or not to the elderly. In this study, the magnitude of the acceleration in x, y, and z axes of the accelerometer sensor is processed into a total value of acceleration. Then the value will be compared with the lower threshold value and the higher threshold value. After that the total value of the acceleration is compared again with the threshold value of the total value orientations. The total value of acceleration is used to distinguish between regular activity and falling. The results of this study indicate that the system developed has the sensitivity values of 89% and specificity of 98%.
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Norhabibah, Siti, Wahyu Andhyka, and Diah Risqiwati. "Design and Build a Fall Detection Monitoring System for the Elderly Using an Accelerometer." JOINCS (Journal of Informatics, Network, and Computer Science) 1, no. 1 (January 25, 2018): 43–52. http://dx.doi.org/10.21070/10.21070/joincs.v1i1.803.
Повний текст джерелаАнотація:
Elderly is a last transitional period of human life. Decrease or disappearance of organ function such as loss of balance, reduced vision and hearing cause the elderly often fall. The limited physical ability of them requires supervision. Supervision is necessary to avoid undesirable thing occurs. Here, a tool called accelerometer can be used to supervise and monitor whether the fall incident occurs or not to the elderly. In this study, the magnitude of the acceleration in x, y, and z axes of the accelerometer sensor is processed into a total value of acceleration. Then the value will be compared with the lower threshold value and the higher threshold value. After that the total value of the acceleration is compared again with the threshold value of the total value orientations. The total value of acceleration is used to distinguish between regular activity and falling. The results of this study indicate that the system developed has the sensitivity values of 89% and specificity of 98%.
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Lukyanov, Dmitry P., Alexander M. Boronakhin, Sergey Yu Shevchenko, Mariya A. Khivrich, and Temurmalik A. Amirov. "Microaccelerometer on Surface Acoustic Waves with a Ring Resonator on Anisotropic Material." Journal of the Russian Universities. Radioelectronics 22, no. 5 (December 4, 2019): 116–29. http://dx.doi.org/10.32603/1993-8985-2019-22-5-116-129.
Повний текст джерелаАнотація:
Introduction. Diagnostic systems are designed to monitor the condition of operational components (for example, on the railway). It is imperative that micro-electromechanical systems (MEMS) equipped with acceleration sensors (accelerometers) be used as part of measuring diagnostic systems. It is known that accelerometers are operated under increased vibration and repeated shock loads. This imposes a limitation both on the accelerometer design and the properties of materials from which these devices are produced.Aim. To develop a micromechanical accelerometer (MMA) for surface acoustic waves (SAW), capable of measuring shock effects.Materials and methods. The theoretical part of the study was carried out using the mathematical theory of differential equations, theoretical mechanics, finite element analysis and elements of SAW theory. In the course of the work, the following methods of mathematical processing were applied: MATLAB, Mathcad, Maple, COMSOL Multiphysics, OOFELIE: Multiphysics, Bluehill3 software, CorelDRAW. Experimental studies were also conducted using the INSTRON 5985 floor automated test system.Results. An original design of MMA on a SAW capable of measuring shock effects in hundreds of g was proposed. A sensing element (SE) of the sensor was developed. An analysis of the plate materials for their use as part of the SAW-based MMA design showed that SE from the quartz ST-cut material has a wider range of measured accelerations and a higher sensitivity threshold than SE from the YX-128˚ cut-off lithium niobate material. Requirements were developed to increase the SE sensitivity threshold. Design requirements were developed, and an interdigital transducer (IDT) topology in the form of a ring resonator was proposed. The following output characteristics were assessed: sensitivity threshold, dynamic range and scale factor. In addition, a procedure was developed for calculating MMA on a SAW with a ring resonator on an anisotropic material. It was found that the developed SE is characterized by a high sensitivity threshold, a wide dynamic range and a low transverse sensitivity.Conclusion. The technique proposed for designing a sensing element for use in solid-state linear acceleration sensors facilitates, depending on technical requirements, selection of construction materials and sensor design. Due to the originality of the design and engineering solutions, the proposed accelerometer allows measurements to be carried out across a wide range of impact loads.
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Han, Yingzhou, Guozhe Xuan, Jiahao Zhao, and Zheng You. "Low-G Triggered Acceleration Switch for Near-Zero Power Wake-Up Application." Micromachines 13, no. 8 (August 17, 2022): 1333. http://dx.doi.org/10.3390/mi13081333.
Повний текст джерелаАнотація:
A low-g triggered micro-electromechanical system (MEMS) resonant acceleration switch is designed, fabricated and tested in this paper for near-zero power wake-up applications. The switch is actuated by ambient low-g vibration, consuming zero power while waiting for vibration at its resonant frequency. A cantilever beam and proof mass structure is adopted in the switch. The patterns of spiral cantilever beams are designed for low resonant frequency and threshold. Once the vibration with resonant frequency exceeds the acceleration threshold of the switch, the movable electrode becomes sufficiently displaced to contact the fixed electrodes and causes them to trigger. The dynamic responses of the switch are tested on a piezoelectric stack. The experimental results show that the switch closes under vibration at a frequency as low as 39.3 Hz and at an acceleration threshold of 0.074 g. A wake-up sensor node connected to the switch can awaken when the switch is under vibration as an intended characteristics.
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Alhusban, Zaid. "Studying sediment transport dynamics by using the Smart sphere." International Journal of Energetica 5, no. 1 (June 30, 2020): 01. http://dx.doi.org/10.47238/ijeca.v5i1.122.
Повний текст джерелаАнотація:
A new method is introduced by using high precision accelerometer and gyroscope micro-electromechanical sensors (MEMS), which can record Lagrangian observations of sediments and shed light into the dynamics of sediment transport processes at above threshold conditions. The sensor can be used under a range of well-controlled flow conditions and can record measurements at high frequency (200 Hz), which can be used at the field. The smart sphere performance was evaluated by comparing its rotation and acceleration readings from the sensors to the video recordings of both top and underwater high-speed camera for a range of flow rates and sphere densities. Furthermore, an initial attempt to compare the smart-sphere’s velocity is achieved, by transforming the particle’s velocity from the Lagrangian frame of reference, obtained from the inertial sensor, to its velocity at the Eularian frame, obtained from the top camera.
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Jung, Byung, Young Huh, and Jin-Woo Park. "A Self-Powered, Threshold-Based Wireless Sensor for the Detection of Floor Vibrations." Sensors 18, no. 12 (December 5, 2018): 4276. http://dx.doi.org/10.3390/s18124276.
Повний текст джерелаАнотація:
Smart buildings will soon be a reality due to innovative Internet of Things (IoT) applications. IoT applications can be employed not only for energy management in a building, but also for solving emerging social issues, such as inter-floor noise-related disputes in apartments and the solitary death of an elderly person. For example, acceleration sensors can be used to detect abnormal floor vibrations, such as large vibrations due to jumping children or unusual vibrations in a house where an elderly person is living alone. However, the installation of a conventional accelerometer can be restricted because of the sense of privacy invasion. In this study, a self-powered wireless sensor using a threshold-based method is studied for the detection of floor vibrations. Vibration levels of a bare slab in a testbed are first measured when a slab is impacted by a bang machine and an impact ball. Second, a piezoelectric energy harvester using slab vibration is manufactured to generate electrical power over a threshold. Next, the correlation among harvested energy, floor vibration, and impact noise is studied to check whether harvested energy can be employed as a condition detection threshold. Finally, a prototype of a self-powered wireless sensor to detect abnormal conditions in floor vibrations is developed and its applicability is demonstrated.
Дисертації з теми "Threshold acceleration sensor"
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Todd, Benjamin L. "A Compliant Threshold Acceleration Sensor Integrated with Radio Frequency Identifiable Tags." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2456.pdf.
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Ramanathan, Murugappan. "Towards the Development of MEMS g-Switches." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/5978.
Повний текст джерелаАнотація:
Accelerometers are sensors that measure and record the acceleration of an object in motion. They typically contain spring and mass elements that are set into vibration upon any impressed acceleration. The characteristics of their continuous vibration are used to extract the acceleration information. MEMS g-switch accelerometers are a special class of such sensors that sense a threshold acceleration and act as a switch for some other action that must ensue only if the threshold acceleration is achieved. Such accelerometers are used for impact detection and very high-speed propulsion, e.g., rockets. There are two types of g-switches — Latch type and Non-latch type. Non-latch type accelerometers have a proof-mass suspended by springs (beams) and two stationary electrodes, on experiencing an acceleration, this proof-mass touches the two electrodes closing an external electrical circuit and allowing an electric current to flow through the circuit as long as there is contact. This current flow indicates that a particular level of acceleration is reached. Latch type accelerometers, on the other hand, have compliant electrodes that latch on to the proof-mass on experiencing the threshold acceleration, maintaining the switch in ON state permanently from the instant the threshold acceleration is reached. We have designed, developed and studied both types of g-switches in this work. Time of contact (in case of non-latch type switches), contact resistance, and response time are key parameters that affect the performance of these devices. Energy-based approach is used in the design of these switches with appropriate displacement and velocity constraints that enforce the threshold condition. Dynamic characterisation is done on the fabricated devices to extract their modal parameters. An impulse acceleration is generated by means of an impact using a drop test equipment and high-speed video imaging is used to extract the device response. The experimental response is compared with FEM simulation results. The high-speed video imaging is also used to study the dynamics of the contact at the micro-second time scale. Electrical switching experiments are done for varying magnitude of the shock profile to find the threshold g-level of the switches. For the latch type accelerometers, to reset the switch and make them reusable after latching, a Chevron beam (bent beam) type thermal actuator is designed to accomplish the unlatching. In case of large vertical off-set between the proof-mass and the electrode, a horizontally actuated bent beam mechanism is used to accomplish the unlatching. Thus the study undertaken reports a complete development of the target g-switches.
Частини книг з теми "Threshold acceleration sensor"
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Li, Lili, Hao Luo, He Qi, and Feiyu Wang. "Sensor Fault Diagnosis Method of Bridge Monitoring System Based on FS-LSTM." In Advances in Frontier Research on Engineering Structures, 487–501. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8657-4_44.
Повний текст джерелаАнотація:
AbstractAn improved long-short-term memory neural network (FS-LSTM) fault diagnosis method is proposed based on the problems of damage false alarm, data of health monitoring system incorrect caused by sensor fault in bridge structure health monitoring system. The method is verified by simulating three-span continuous beams to install several sensors and considering the five failures of one sensor, the faults such as: constant, gain, bias, gain linearity bias, and noise. At first, several pieces of white noise data are randomly generated, and each piece of white noise data is applied as a ground pulsation excitation to the structure support, and the acceleration response of the structure at the sensor location is calculated. Simultaneously, each structural response record of each sensor adds white noise with the same signal-to-noise ratio to obtain the test value of each sensor; Secondly, in order to study the generality, except for the five types of faulty sensors in sequence, one sensor is randomly selected from each of the remaining spans, to verify whether there will be a situation where an intact sensor is misdiagnosed as a faulty sensor; Finally, the FS-LSTM network is constructed through the training set to predict the acceleration data, determine the sensor fault threshold, and compare the residual sequence with the fault threshold to diagnose whether the sensor is faulty. The case research of a three-span continuous beam shows that when the above-mentioned five types of faults occur in the sensor, the proposed method can correctly determine whether the sensor is faulty, and it will not be misdiagnosed, which can be used for daily bridge health monitoring. Furthermore, it provides a new method for the maintenance of the bridge health monitoring system.
Тези доповідей конференцій з теми "Threshold acceleration sensor"
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Medina, Lior, Rivka Gilat, and Slava Krylov. "Sub g Threshold Acceleration Sensor Incorporating Latched Bistable Beam." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85181.
Повний текст джерелаАнотація:
We present a concept and a theoretical feasibility study of a sub g threshold inertial micro sensor, which incorporates a curved bistable beam as a suspension element. For certain range of geometric parameters such a beam can exhibit lathing, namely remain in its switched configuration at zero actuating force. Since the device can be released from its latched state by an external acceleration force, it can therefore serve as a threshold inertial switch. While the snap-through force, associated with the switching from the initial to the buckled state, cannot be reduced without decreasing the frequency of the device, the release value of the acceleration can be tailored to be arbitrarily low. This allows design of a devices with sufficiently high stiffness in the initial and latched configurations, but with a very low release threshold. Our model show that for appropriately chosen parameters, it is possible to design a sub g threshold acceleration micro switch of realistic dimensions.
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Xu, Qiu, Lvjun Wang, Alhammam Niyazi, and Mohammad I. Younis. "Multi-Threshold MEMS Shock Sensor for Quantitative Acceleration Measerements." In 2021 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers). IEEE, 2021. http://dx.doi.org/10.1109/transducers50396.2021.9495396.
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Wycisk, Michael, Josef Binder, Sven Michaelis, and Hans-Joerg Timme. "New sensor-on-chip technology for micromechanical acceleration-threshold switches." In Asia Pacific Symposium on Microelectronics and MEMS, edited by Neil W. Bergmann, Olaf Reinhold, and Norman C. Tien. SPIE, 1999. http://dx.doi.org/10.1117/12.364462.
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Pallay, Mark, Alwathiqbellah I. Ibrahim, and Shahrzad Towfighian. "A MEMS Threshold Acceleration Switch Powered by a Triboelectric Generator." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85543.
Повний текст джерелаАнотація:
In this paper a novel electrostatic MEMS combined shock sensor and normally-closed switch is presented. The switch uses combined attractive and repulsive forcing to toggle a cantilever beam to and from the pulled-in position. The attractive force is generated through a parallel plate electrode configuration and induces pull-in. The repulsive force is generated through electrostatic levitation from a third electrode and serves to pull the beam out of its pulled-in position. A triboelectric transducer converts impact energy to electrical energy to provide voltage for the third electrode, which temporarily opens the switch if enough impact energy is supplied. Triboelectricity addresses the high voltage requirement for electrostatic levitation. The multi-electrode sensor also addresses the low current output from the generator because it acts as an open circuit between the parallel plate and levitation electrodes. A theoretical model of the switch is derived to analyze stability and the dynamic response of the cantilever. Threshold voltages to pull-in and release the beam through repulsive forcing is calculated. Output voltage plots from a prototype generator under a single impact are applied to the sensor-switch model to demonstrate the working principle of the sensor-switch is feasible.
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Rabanim, Shila, Emil Amir, and Slava Krylov. "Bistable Threshold Sensor With Mechanically Nonlinear Self-Limiting Suspension and Electrostatic Actuation." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-47575.
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We report on the operational principle, modeling, fabrication and characterization of an electrostatically actuated force/acceleration sensor with mechanically nonlinear stiffening suspension. The suspension incorporates initially curved beams oriented in such a way that both the electrostatic and inertial forces applied to the beam’s ends are directed predominantly along the beam. Since the stiffness of the curved beam is significantly lower than that of the straightened beam, the force-displacement dependence of the suspension is of the self-limiting type while the suspension itself serves as a compliant constraint. Application of a softening electrostatic force, provided by a parallel-plate transducer, results in pull-in instability followed by the steep increase in the suspension stifftness and the appearance of an additional stable configuration of the device. In accordance with the model results the dependence between the acceleration and the shift of the pull-in voltage induced by the acceleration is nearly linear and the pull-in voltage monitoring can be used for the measurement of the acceleration. Model results show that using the suggested approach significantly improves device resolution, extends dynamic range, and improves reliability by eliminating contact. Devices of several configurations were fabricated from a silicon on insulator (SOI) substrate using a deep reactive ion etching (DRIE) based process. Preliminary experimental results imply that the suggested approach is feasible.
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Arndt, Mark William, and John F. Wiechel. "Results From Calculating the Acceleration at an ELR Using Measured Responses From Four Steering-Induced Rollover Crashes." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36735.
Повний текст джерелаАнотація:
Four steer-induced rollover crashes were analyzed by calculating the local three-dimensional accelerations at hypothetical seat positions’ Emergency Locking [seat belt] Retractor (ELR). The method for calculating the local acceleration was described in a recent Society of Automotive Engineers (SAE) paper and assumed three-dimensional rigid body motion, recorded acceleration and recorded roll rates at the center of gravity. For a threshold of 0.7 g, results demonstrated that intervals in the vehicle’s response that may cause the ELR’s inertial sensor to move into a neutral zone were limited to localized high-magnitude negative vertical acceleration events during the rollover segment with a maximum calculated duration of 31.7 ms. Changing the threshold to 0.35 g reduced the interval count by 70 percent and maximum duration by approximately 50 percent. Results of the analysis were consistent with prior published research that noted limited and brief periods of instances in rollover crashes when the inertial sensor may be in a neutral zone. Calculating an interval that a vehicle’s response may allow a retractor to move into a neutral zone did not mean that a specific retractor will move into a neutral zone. To asses if a specific retractor will move into a neutral zone its performance should be analyzed. As identified in prior research, occupant kinematics analysis was necessary in determining whether an inertial sensor in a neutral zone during a rollover event will result in belt spool out. It is beyond the scope of the paper to include a complete analysis of occupants’ kinematics.
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Zhao, Jian, Yu Huang, Pengbo Liu, Qifei Fang, and Renjing Gao. "Nonlinear Design Model for Multi-Threshold Accelerometer Utilizing Magnetic Induced Multistable Mechanisms." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85868.
Повний текст джерелаАнотація:
Different from traditional accelerometer, multi-threshold acceleration switch can be triggered to different working states by external accelerations without complex auxiliary circuits and controlling elements, which has great application potentials in aerospace, vehicle safety and consumer electronics. In this paper, a novel multi-threshold acceleration switch with anti-overloading function is designed and fabricated by incorporating both magnetic multi-stable structures and compliant cantilever contacts, which also can be used to distinguish specific acceleration pulse. To enhance the contact reliability, the magnetic compliant locking mechanism is introduced to prevent bouncing back phenomenon under overload acceleration. Considering the air-damping and multi-magnetic fields coupling effect, the dynamic design model is proposed for analyzing the nonlinear switch response. Then, threshold accelerations can be determined as ac1 = 3.78g, ac2 = 10.2g and ac3 = 6.95g in one direction while threshold accelerations in opposite direction are ac4 = 4.9g, ac5 = 8.47g and ac6 = 5.6g. The switch shows excellent threshold acceleration detection capability, and the inertial switch keeps open while the external acceleration is 0.2g less than the predefined threshold value. The experimental results show that the threshold acceleration with specific pulse width can be accurately identified, and the switch can bear strong overload acceleration comparing to traditional switches. Consequently, the proposed design method provides a new way for intelligent mechanical inertial sensors.
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Wittwer, Jonathan W., Michael S. Baker, David S. Epp, and John A. Mitchell. "MEMS Passive Latching Mechanical Shock Sensor." In ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49178.
Повний текст джерелаАнотація:
This paper presents a novel micro-scale passive-latching mechanical shock sensor with reset capability. The device integrates a compliant bistable mechanism, designed to have a high contact force and low actuation force, with metal-to-metal electrical contacts that provide a means for interrogating the switch state. No electrical power is required during storage or sensing. Electrical power is only required to initialize, reset, self-test, or interrogate the device, allowing the mechanism to be used in low-power and long shelf-life applications. The sensor has a footprint of about 1 mm2, allowing multiple devices to be integrated on a single chip for arrays of acceleration thresholds, redundancy, and/or multiple sense directions. Modeling and experimental results for a few devices with different thresholds in the 100g to 400g range are given. Centrifuge test results show that the accelerations required to toggle the switches are higher than current model predictions. Resonant frequency measurements suggest that the springs may be stiffer than predicted. Hammer-strike tests demonstrate the feasibility of using the devices as sensors for actual mechanical shock events.
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Tay, Yi Yang, Rasoul Moradi, and Hamid M. Lankarani. "A Numerical Analysis of Pre-Deployment Effect of Side-Impact Airbags in Reducing Occupant Injuries." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63234.
Повний текст джерелаАнотація:
Side impact collisions represent the second greatest cause of fatality in motor vehicle accidents. Side-impact airbags (SABs), though not mandated by NHTSA, have been installed in recent model year vehicle due to its effectiveness in reducing passengers’ injuries and fatality rates. However, the increase in number of frontal and side airbags installed in modern vehicles has concomitantly led to the rise of airbag related injuries. A typical side-impact mechanical or electronic sensor require much higher sensitivity due to the limited crush zones making SABs deployment more lethal to out-of-position passengers and children. Appropriate pre-crash sensing needs to be utilized in order to properly restraint passengers and reduce passengers’ injuries in a vehicle collision. A typical passenger vehicle utilizes sensors to activate airbag deployment when certain crush displacement, velocity and or acceleration threshold are met. In this study, it is assumed that an ideal pre-crash sensing system such as a combination of proximity and velocity and acceleration sensors is used to govern the SAB pre-deployment algorithm. The main focus of this paper is to provide a numerical analysis of the benefit of pre-deploying SAB in lateral crashes in reducing occupant injuries. The effectiveness of SABs at low and high speed side-impact collisions are examined using numerical Anthropomorphic Test Dummy (ATD) model. Finite Element Analysis (FEA) is primarily used to evaluate this concept. Velocities ranging from 33.5mph to 50mph are used in the FEA simulations. The ATD used in this test is the ES-2re 50th percentile side-impact dummy (SID). Crucial injury criteria such as Head Injury Criteria (HIC), Thoracic Trauma Index (TTI), and thorax deflection are computed for the ATD and compared against those from a typical airbag system without pre-crash sensing. It is shown that the pre-deployment of SABs has the potential of reducing airbag parameters such as deployment velocity and rise rate that will directly contribute to reducing airbag related injuries.
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Nie, Weirong, Zhijian Zhou, Zhanwen Xi, Chao Bu, and Qiao Luo. "A novel dual-threshold MEMS acceleration latching switch." In 2017 IEEE International Symposium on Inertial Sensors and Systems (INERTIAL). IEEE, 2017. http://dx.doi.org/10.1109/isiss.2017.7935667.
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