Research on Precise Control of a Cylinder Delay Oscillation System Based on Response Surface and Genetic Algorithm

A cylinder time-delay oscillation system can be constructed by using air bag and throttle valve. The air bag and throttle valve are used to realize the time-delay transmission of pressure in the feedback circuit, and the feedback pressure is used to promote the reversing of two position five-way valve, so as to realize the reciprocating action of the cylinder. The experimental design is carried out based on the simulation analysis, and the response surface is constructed based on the experimental data to clarify the relationship between the cylinder dwell time and the main component parameters. Based on response surface, genetic algorithm is used to search for the best control parameters to realize the accurate control of cylinder dwell time.

Design of MEMS Capacitive Accelerometer for Automotive Airbag Application

The objective of this paper is to bring out the responsiveness of the capacitive accelerometer with changes in the input acceleration. The performance analysis of the device is done using COMSOL MULTIPHYSICS .It is analysed that when the capacitance reaches a threshold value, amplifying the electric signal the air bag could be initiated.3D capacitive accelerometers which are less prone to noise and temperature variations. They reduce the severity of the accident by sensing the sudden increase in negative acceleration and deployment of the airbags. The dependency between the acceleration and the capacitance has been analysed. The sensitivity of the device with respect to forces in real time accident conditions is observed.

A Feasibility Study on Smart Mattresses to Improve Sleep Quality

Good sleep quality is essential, especially for clinical users. Sleep disorders not only impair the success rate of treatment but also delay recovery. They can seriously interfere with treatment outcomes and even endanger a user’s life. In this study, we created a smart mattress containing 10 × 18 air packs and control units. Each air pack contains a set of pressure and height sensors and two air valves. Each row control unit can detect and adjust the pressure and height of each air bag in the row. When the bed body is turned on, it automatically initializes, adjusts the state of each air bag to the same height and pressure, and enters a slow scanning state. When perceived objects or people are lying on the bed, the bed automatically perceives the human body structure and body pressure matrix, increases the scanning speed for more timely and accurate measurements of the digital matrix and forming pressure by matrix-normalized processing, and then uses local pressure variance detection to automatically adjust to the sleeping position of the human body and thus achieve a uniform force distribution and a comfortable state. Finally, pressure matrix binarization was used to match sleeping position templates to identify the best template for automatic recognition of the sleeping position. The experimental results show that the sleeping position recognition method has high accuracy, recall, and precision. Our mattress is designed with interfaces for external devices. In future research, the smart mattress can connect to an auxiliary part of a smart ecosystem consisting of a smart pill box, a smart lighting system, and a microclimate system, which is expected to yield a more comprehensive intelligent ward to explore the possibility of improving sleep quality.

Mask-Type Sensor for Pulse Wave and Respiration Measurements and Eye Blink Detection

This paper reports on a mask-type sensor for simultaneous pulse wave and respiration measurements and eye blink detection that uses only one sensing element. In the proposed sensor, a flexible air bag-shaped chamber whose inner pressure change can be measured by a microelectromechanical system-based piezoresistive cantilever was used as the sensing element. The air bag-shaped chamber is fabricated by wrapping a sponge pad with plastic film and polyimide tape. The polyimide tape has a hole to which the substrate with the piezoresistive cantilever adheres. By attaching the sensor device to a mask where it contacts the nose of the subject, the sensor can detect the pulses and eye blinks of the subject by detecting the vibration and displacement of the nose skin caused by these physiological parameters. Moreover, the respiration of the subject causes pressure changes in the space between the mask and the face of the subject as well as slight vibrations of the mask. Therefore, information about the respiration of the subject can be extracted from the sensor signal using either the low-frequency component (<1 Hz) or the high-frequency component (>100 Hz). This paper describes the sensor fabrication and provides demonstrations of the pulse wave and respiration measurements as well as eye blink detection using the fabricated sensor.

Experimental Investigation of Friction Between Vehicle Air Bag Material and Head Skin for Humans and Crash Test Dummies

Motor vehicle crashes can produce serious head or brain injuries due to contact with interior vehicle structures. It has been found through both field data analysis and experimental testing that many of these brain injuries occur in oblique crashes, even with the deployment of air bags. Research has determined that rotational head velocity is strongly correlated to the risk of brain injury through metrics such as Brain Rotational Injury Criteria (BrIC). The severity of rotational head motion could be related to the friction force developed during contact between the head and air bags. Although crash test dummy head skins are designed with appropriate mass properties and anthropometry as well as material type and thickness to emulate the proper impact response of the human head, it is not known whether they accurately represent the frictional properties of human skin during air bag interaction. This study experimentally characterized the friction coefficient between human skin and air bag fabrics using a pin-on-disc tribometer. Skin samples were harvested from different locations (forehead, cheeks, chin) from specimens of post-mortem human subjects (PMHS). Fabric samples were cut from six different air bags spanning various vehicle manufacturers and interior mounting locations. For comparison, four types of dummy head skin samples were also tested against the air bag samples. Friction was measured between different skinair bag material combinations at various linear velocities and normal forces. It was determined that the difference between human and dummy skin friction with the air bag samples varied significantly among different air bags; however, the effect of linear speed, normal force, and human skin sample harvesting location on friction coefficient is negligible. Except for one air bag fabric, the friction coefficients of the dummy skin are higher than those quantified for human skin.