• 한국자동차공학회논문집
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• 제24권6호
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• pp.660-667
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• 2016

Maintaining proper tire air pressure is an essential element in ensuring vehicle safety. UHP Tires that boast of many safety features are increasing in the market. In particular, the development of "Self-Inflating Tire" technology is accelerating around the globe. Self-inflating tire refers to a technique for maintaining appropriate tire pressure. An internal regulator senses when tire inflation pressure has dropped below the set air pressure. The tire boosts air through the valve when rolling and compressed air enters into the tire. This procedure keeps the tire air pressure at an appropriate level and increases tire safety. Flow analysis of the internal tube is required to examine self-inflating tires. In this study, a method of tube flow analysis using the FSI Method is proposed. The valve system is also implemented to optimize the regulator and sensor.

• PNF and Movement
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• 제19권3호
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• pp.375-382
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• 2021

Purpose: The objectives of the present study were to investigate the disadvantages of tire pressure asymmetry of a wheelchair tire and recommend the criterion for appropriate tire pressure without generating negative changes in the musculoskeletal system in asymptomatic participants. Methods: Fourteen asymptomatic participants were asked to sit in pressure-controlled wheelchairs and perform desk work for 20 minutes in each tire condition. The asymmetry of the tire conditions was set as 0% difference, 25% difference, and 50% difference from the recommended pressure. The pelvic alignment and muscular recruitment represented as a flexion-relaxation ratio (FRR) were measured at pre-test, and after each condition of desk work. The displacement of the center of pressure (COP) was measured during the desk work. Results: The tire air pressure condition significantly affected the FRR and COP (P < 0.05). Both sides of the FRR values were significantly higher under the symmetrical tire conditions (0% difference) and pre-test, compared with the asymmetrical tire condition of 50% difference (P < 0.05). The mediolateral COP displacement of the asymmetrical tire conditions (25% and 50% difference) was significantly higher than that of the symmetrical tire conditions (0%) (P < 0.05). Conclusion: Asymmetrical tire conditions could cause changes in the muscle recruitment pattern of the erector spine and mediolateral COP displacement. Tire pressure asymmetry higher than 50% could be a risk factor for prevalence of back pain, so this level of asymmetry in tire pressures should be cautioned against for wheelchair users.

• 한국소음진동공학회논문집
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• 제20권3호
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• pp.249-256
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• 2010

This paper presents performance analysis of a quarter-vehicle magneto-rheological(MR) suspension system with respect to different tire pressure. As a first step, MR damper is designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial mid-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the manufactured MR damper, the quarter-vehicle MR suspension system consisting of sprung mass, spring, tire and the MR damper is constructed in order to investigate the ride comfort. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of quarter-vehicle MR suspension system. Ride comfort characteristics such as vertical acceleration RMS and weighted RMS of sprung mass are evaluated under various road conditions.

• 항공우주시스템공학회지
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• 제4권2호
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• pp.1-9
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• 2010

An airless tire has advantages over the conventional pneumatic tire in terms of flat proof and maintenance free. According to the recently disclosed inventions on the airless tire, non-pneumatic tire (NPT) consists of the flexible polygon spokes. Considering the NPT structure, the spokes undergo the tension-compression cyclic loading while the tire rolls. Therefore the spokes of NPT are required to have both stiffness and resilience under the cyclic tensile-compressible loading. In general, if a material has a high stiffness, it shows a low elastic strain limit. In this paper, using the auxetic honeycomb structure with negative poissons's ratio, the spokes of NPT tire are designed to have both stiffness and resilience. Finite element based numerical simulation of the contact pressure of a NPT is carried out with ABAQUS.

• 한국지능시스템학회논문지
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• 제22권5호
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• pp.663-668
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• 2012

차량의 각 타이어에 부착된 센서에서 압력과 온도 등을 측정하여 측정된 데이터를 차량의 무선 수신기에 전송하여 디스플레이에 타이어의 상태를 표시하는 TPMS(Tire Pressure Monitoring System)는 차량의 운행 또는 정지 중에 타이어의 상태를 수시로 점검하여 운전자에게 타이어 상태정보를 제공하는 안전보조 장치이다. TPMS는 각 타이어에서 측정되는 데이터를 전송하기위해 무선통신을 이용하는데, 정확한 데이터 전송을 방해하는 외부 전기 및 전자장치에 의한 간섭이 존재할 수 있다. 본 논문에서는 정확한 데이터 전송에 영향을 주는 간섭을 제거하고 MVDR(Minimum-Variance Distortionless-Response) 보다 낮은 복잡도를 가지는 GSC(Generalized Sidelobe Canceler) 기반의 TPMS 간섭제거 방식을 제안한다. 컴퓨터 시뮬레이션을 통하여 본 논문에서 제안된 간섭제거 기술의 성능을 확인한다.

• 전기전자학회논문지
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• 제24권1호
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• pp.33-39
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• 2020

본 논문에서는 타이어의 물리적인 요소 중 하나인 압력정보를 이용해서 자동차의 하중 표출이 가능한 타이어 공기압 측정 기술을 사용한 차량의 적재중량 측정시스템 설계 기법을 제안한다. 제안된 기법은 하중 및 진동에 의한 노이즈 보정, 기체유량 보정, 데이터 믹서, 중량 환산 등의 4가지 과정으로 구성된다. 하중 및 진동에 의한 노이즈 보정에서는 외부충격 및 차량이 주행 중 발생하는 진동 등에 의해 타이어의 내부 압력이 상승하는 노이즈를 제거한다. 기체유량 보정 과정에서는 하중 및 진동에 의한 노이즈 보정 과정을 거친 데이터에 대하여 지면의 온도상승에 의해 타이어의 내부 압력이 상승하는 노이즈를 제거한다. 데이터 믹서 과정에서는 화물적재 시 타이어에 수직으로 전달이 되어 타이어의 압력변화에 따른 공차, 중차, 만차에 대한 하중과 압력 등을 분류하게 된다. 중량 환산 과정에서는 하중 및 진동에 의한 노이즈 보정 및 기체유량 보정을 거친 데이터를 사용하여 중량 환산 알고리즘을 통해 중량으로 표출된다. 중량 환산 알고리즘은 하중과 압력변화에 대한 선형 함수의 기울기인 중량 환산 Factor를 구하여 중량을 환산한다. 본 논문에서 제안된 타이어 공기압 측정 기술을 사용한 차량의 적재중량 측정 시스템의 정밀도를 평가하기 위해 자체적으로 테스트 베드를 구축하여 평가하였다. 하중 및 진동에 의한 노이즈 보정 결과와 기체 유량 데이터 보정 결과는 신뢰성 있는 결과를 나타내었다. 또한 중량 정밀도 반복 실험도 국내 업체 기준치인 90% 보다 우수한 중량 정밀도를 나타내었다.

• Journal of Biosystems Engineering
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• 제27권1호
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• pp.1-10
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• 2002

This study was carried out to investigate experimentally the effect of three factors(dynamic load, inflation pressure and number of passes of tire) on soil compaction under the tire. The experiment were conducted with a 6.00R14 radial-ply tire for sandy loam soil using soil bin system. To evaluate the effect of three factors on soil compaction under the tire, the sinkage. density and volume of soil under the tire were measured fur the three levels of dynamic load(1.17kN, 2.35kN and 3.53kN), for the three levels of tire inflation pressure(103.42kPa, 206.84kPa and 413.67kPa), and for three different number of passes(1, 3 and 5). The results of this study can be summarized as follows : 1. As dynamic load, inflation pressure and number of passes of the tire increased, soil sinkage and density increased. and volume of soil decreased. Thus increase in dynamic load, inflation pressure and number of passes of the tire would increase soil compaction. 2. The effect of tire inflation pressure on sinkage. density and volume of soil under the tire was relatively less than that of the dynamic load. Therefore, it was concluded that dynamic load was more important factor affecting soil compaction in comparison to the inflation pressure of tire. 3. The effect of three different factors on sinkage, density and volume of soil decreased as the soil depth increase. Consequently, it was fecund that soil compaction at a shallow depth in soil was larger than that at deep place in soil.

• 센서학회지
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• 제14권4호
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• pp.265-271
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• 2005

In this study, a variable capacitive pressure sensor is fabricated for TPMS (Tire Pressure Monitoring System). This study is for developing sensors which consecutively measure the tire pressure given as 30 psi from the industrial standard. For improving non-linearity of the prior capacitive pressure sensors, it is suggested that touch mode capacitive pressure sensor be applied. In addition, initial capacitance is designed as small as possible for the conformity to the wireless sensor. ANSYS, commercial FEA package, is used for designing and simulating the sensor. The device is progressed by MEMS (Micro Electro Mechanical Systems) fabrication and packaged with PDMS. The result is obtained sensitivity, 1 pF/psi, through a pressure test. The simulation result is discrepant from experiment one. Wafer's uniformity is presumed as the main reason of discrepancy.

• 한국전자통신학회논문지
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• 제7권6호
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• pp.1327-1335
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• 2012

타이어 파손으로 인한 사고를 사전에 방지하기 위해 개발된 TPMS(Tire Pressure Monitoring System)는 타이어에 장착된 센서부로부터 전송된 데이터를 기반으로 타이어의 이상 유무를 디스플레이 장치에 표시하고 운전자가 실시간으로 타이어의 온도, 압력 등의 정보를 수시로 파악하여 최적의 주행조건을 유지시켜주기 위한 안전보조시스템이다. 무선통신을 사용하는 TPMS는 측정된 데이터의 송수신 시 간섭이나 잡음으로 인해 데이터 전송 시 수신 오류가 발생할 수 있다. 이러한 문제점을 해결하기 위해 스위칭(Switching), MVDR(Minimum-Variance Distortionless-Response), GSC(Generalized Sidelobe Canceler) 빔형성기(Beamformer) 등과 같은 간섭제거에 효율적인 대표적인 빔형성 기술들을 사용한다. 본 논문에서는 이 세 가지 빔형성기의 복잡도를 계산하여, 복잡도 성능 비교에 대한 수학적 근거를 제시한다. 컴퓨터 시뮬레이션을 통하여 본 논문에서 고려된 세 가지 빔형성기의 복잡도 성능을 확인한다.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.210-216
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• 2016

In this work, performance analysis to improve ride comfort of an ER (electrorheological) fluid damper for a mid-sized passenger vehicle in terms of tire pressure is presented. An ER damper by considering specification for a mid-sized commercial passenger vehicle is proposed and mechanically designed. After manufacturing and assembling the proposed ER damper with design parameters, their performance such as field-dependent damping forces are experimentally measured. A quarter-vehicle ER ECS (Electronic Control Suspension) system consisting of the ER damper, sprung mass, spring, sky-hook controller and tire is constructed to analysis the ride comfort performances. Vertical tire stiffness with different tire pressure is experimentally measured and investigated. In addition, ride comfort analysis such as vertical acceleration root mean square (RMS) of sprung mass is investigated under bump road using quarter-vehicle test equipment.