Search Results (51)

This study investigates the perception of postural discomfort experienced by passengers seated in the middle rear seat of a vehicle—an area often overlooked in ergonomic research. A total of 20 participants (12 males and 8 females) were involved in a pilot test using two car models: a City Car (Fiat Panda) and a C-SUV (Renault Arkana). Each participant completed a short on-road ride (~24 min, 11.7 km) in both vehicles. Discomfort was assessed using a 5-point Likert scale, considering both overall and localized body discomfort, as well as other elements/factors, such as those involved in the human–car interaction (e.g., the central tunnel, the headrest, AC vents, and other passengers). The results showed that overall discomfort was significantly higher in the City Car (mean: 3.75 ± 0.72) compared to the SUV (mean: 3.00 ± 1.16). The most affected body regions in the City Car were the arms (mean: 3.95), knees (3.90), and legs/feet (3.55). In the SUV, discomfort was lower across all regions, with the arms (3.15) and knees (3.05) still being notably impacted. Strong correlations were observed between discomfort and several vehicle features: backrest width, headrests, interference with adjacent passengers, and rear air conditioning vents. This study highlights specific ergonomic issues in the middle rear seat and suggests design improvements, including wider backrests and headrests, repositioned air vents, and the inclusion of lateral supports. These findings offer actionable insights for automotive manufacturers to enhance passenger comfort in multi-passenger configurations. Full article

Automotive NVH (Noise, Vibration, and Harshness) performance significantly impacts driving comfort and traffic safety. Vehicles exhibiting superior NVH characteristics are more likely to achieve consumer acceptance and enhance their competitiveness in the marketplace. In the development of automotive NVH performance, traditional vibration reduction methods have proven to be mature and widely implemented. However, due to constraints related to size and weight, these methods typically address only high-frequency vibration control. Consequently, they struggle to effectively mitigate vehicle body and component vibration noise at frequencies below 200 Hz. In recent years, acoustic metamaterials (AMMs) have emerged as a promising solution for suppressing low-frequency vibrations. This development offers a novel approach for low-frequency vibration control. Nevertheless, conventional design methodologies for AMMs predominantly rely on empirical knowledge and necessitate continuous parameter adjustments to achieve desired bandgap characteristics—an endeavor that entails extensive calculations and considerable time investment. With advancements in machine learning technology, more efficient design strategies have become feasible. This paper presents a tandem neural network (TNN) specifically developed for the design of AMMs. The trained neural network is capable of deriving both the bandgap characteristics from the design parameters of AMMs as well as deducing requisite design parameters based on specified bandgap targets. Focusing on addressing low-frequency vibrations in the back frame of automobile seats, this method facilitates the determination of necessary AMMs design parameters. Experimental results demonstrate that this approach can effectively guide AMMs designs with both speed and accuracy, and the designed AMMs achieved an impressive vibration attenuation rate of 63.6%. Full article

A textile woven presence sensor was previously presented to demonstrate its functionality in eliminating some false positives on car seat presence sensors. After studying the functionality, the next characteristic that the textile sensor should demonstrate is its reliability. The woven sensor was prepared to be tested against ageing. The ageing cycle was prepared according to the UNE-EN ISO 17228:2015 standard. Nine woven sensors are prepared, seven of them face the aging test, and two are selected as reference sensors. The characterization of the woven sensor has been carried out through a microcontroller measurement circuit that obtains the cycles to charge the sensor. Comparison of the results obtained shows that the effects of ageing are negligible. The behavior of the aged sensors is similar to that of the reference sensors, indicating that the variations in the values of both aged and reference sensors are provoked by the environmental conditions during the measurements. To support this argument, a statistical study based on a t-Student analysis was carried out. After 4 ageing cycles, the functionality of the sensors remains unaffected. This research proves the reliability of the woven textile sensor, which encourages its use in automotive applications. Full article

Prolonged driving is associated with fatigue and reduced comfort, jeopardizing driver safety. This study proposes an innovative Anti-Fatigue Massage Function (AFMF) system integrated into a driver’s seat to improve subjective comfort and decrease compensatory movements during extended driving due to fatigue. In total, 24 participants (12 males, 12 females) completed two 60 min simulated driving sessions—one with the AFMF activated and one with it deactivated. Subjective comfort was measured every 10 min using a 5-point Likert scale, while objective In-Chair Movements (ICMs) were manually recorded by expert researchers from dual-camera recordings. ART ANOVA revealed that the AFMF-equipped seat significantly enhanced comfort ratings and reduced ICM frequencies compared to the deactivated condition. These findings suggest that the AFMF system can enhance driver well-being and mitigate fatigue-related risks during prolonged driving. Full article

Vibration can have a significant impact on long-term health, driver comfort, and vehicle performance. With a focus on steering wheel vibrations, this study examines both general and local vibrations that affect the driver. Under real-world conditions, a series of controlled test drives were conducted, with high-precision accelerometers mounted on the driver’s seat and steering wheel recording vibration data. The measurements were conducted in accordance with ISO 5349 and ISO 2631-1, which guaranteed a consistent assessment of vibration exposure. The results suggest that the daily vibration exposure for general vibrations at the driver’s seat is significantly lower than the legal limit, as evidenced by the presence of significant frequencies in the vertical (Z) axis. Nevertheless, steering wheel vibrations may cause pain due to their proximity to the resonance frequencies of the human hand–arm system, which have frequency maxima at approximately 35 Hz and harmonic 70 Hz. Additionally, the vibration intensity was elevated at vehicle velocities between 70 and 80 km/h, suggesting the potential presence of a resonance effect within the suspension or powertrain. The results emphasize the significance of advanced vibration reduction strategies in enhancing driver comfort and safety, including the implementation of a well-designed steering system and enhanced seat absorption. This research offers valuable insights for automotive engineers and ergonomics specialists who are interested in minimizing long-term health risks and vibration-induced fatigue. The aim of this study is to indicate the areas of the drive system fault that have a direct impact on the vibrations of the body structure. The article presents an analysis of the recorded vibration results based on which of the areas of change in the comfort of using the vehicle were selected. Full article

In-vehicle physiological sensing is emerging as a vital approach to enhancing driver monitoring and overall automotive safety. This pilot study explores the feasibility of a pressure-based system, repurposing commonplace occupant classification electronics to capture respiration signals during real-world driving. Data were collected from a driver-seat-embedded, fluid-filled pressure bladder sensor during normal on-road driving. The sensor output was processed using simple filtering techniques to isolate low-amplitude respiratory signals from substantial background noise and motion artifacts. The experimental results indicate that the system reliably detects the respiration rate despite the dynamic environment, achieving a mean absolute error of 1.5 breaths per minute with a standard deviation of 1.87 breaths per minute (9.2% of the mean true respiration rate), thereby bridging the gap between controlled laboratory tests and real-world automotive deployment. These findings support the potential integration of unobtrusive physiological monitoring into driver state monitoring systems, which can aid in the early detection of fatigue and impairment, enhance post-crash triage through timely vital sign transmission, and extend to monitoring other vehicle occupants. This study contributes to the development of robust and cost-effective in-cabin sensor systems that have the potential to improve road safety and health monitoring in automotive settings. Full article

Growing interest in microphone array technology has been observed in the automotive industry and in this work, specifically, for Active Noise Control (ANC) systems. However, the human presence always limits the usage of microphone arrays in driving conditions at the driver’s seat. This is often the most important position of the car cabin; a wearable microphone array is particularly interesting. In this paper, a wearable helmet microphone array is presented featuring 32 microphones arranged over the surface of a helmet, which also integrates a specially designed Analog-to-Digital (A/D) converter, delivering digital signals over the Automotive Audio Bus (A²B). Digital signals are collected using a control unit located in the passenger compartment. The control unit can either deliver digital signals to a personal computer or analog signals to an external acquisition system, by means of Digital-to-Analog (D/A) converters. A prototype was built and acoustically characterized to calculate the beamforming filter matrix required to convert the recordings (pressure signals) into Ambisonics signals (a spatial audio format). The proposed solution was compared to the reference spherical microphone array of the last decade, demonstrating better performance in sound source localization at low frequencies, where ANC systems are mostly effective. Full article

This study explores the integration of a custom-designed pneumatic spring into a car-seat cushion and its interaction with a simplified human body model using the Finite Element Method (FEM). A 3D half-symmetry FEM framework, developed from experimental data, ensured computational efficiency and convergence. This research bridged experimental and numerical approaches by analyzing the contact pressure distributions between a seat cushion and a volunteer with representative biometric characteristics. The model incorporated two material groups: (1) human body components (bones and muscles) and (2) seat cushion materials (polyurethane foam, latex, and fabric tape). Mechanical properties were obtained from both the literature and experiments, and simulations were conducted using MSC.Marc software under realistic boundary and initial conditions. The simulation results exhibited strong agreement with experimental data, validating the model’s reliability in predicting contact pressure distribution and optimizing seat cushion designs. Contrary to the conventional notion that uniformly distributed contact pressure inherently enhances comfort, this study emphasizes that the precise localization of pressure plays a crucial role in static and long-term seating ergonomics. Both experimental and simulation results demonstrated that modulating the pneumatic spring’s internal pressure from 0 kPa to 25 kPa altered peak contact pressure by approximately 3.5 kPa (around 20%), significantly influencing pressure redistribution and mitigating high-pressure zones. By validating this FEM-based approach, this study reduces dependence on physical prototyping, lowering design costs, and accelerating the development of ergonomically optimized seating solutions. The findings contribute to a deeper understanding of human–seat interactions, offering a foundation for next-generation automotive seating innovations that enhance comfort, fatigue reduction, and adaptive pressure control. Full article

Flexible polyurethane foam (FPUF) is extensively applied in multiple applications, including automotive, construction, furniture cushioning, and transportation seating, due to its outstanding mechanical properties, sound absorption, breathable characteristics, and versatility. However, FPUF is highly flammable and releases significant quantities of smoke and harmful gases when burned, which presents considerable safety hazards and has led to extensive research into flame retardant solutions. This review covers the development of both conventional and bio-based flame-retardant agents, including reactive-type and additive-type FRs, and surface coating methods, with a focus on their preparation, characterization methods, and underlying flame retardant mechanisms. Additionally, innovative flame retardant technologies, particularly surface coatings, are discussed in terms of their impact on thermal stability, mechanical performance, and smoke toxicity reduction in the resulting FPUFs. The review also highlights future research priorities and significant challenges, including environmental concerns, cost-effectiveness, and durability. Future research will need to focus on improving flame retardant efficiency while also considering the environmental impact and recyclability of materials, aiming for the green and sustainable development of FPUFs. Full article

As components in direct contact with drivers and passengers in complex and challenging road conditions, automotive seats need to effectively absorb and isolate vibrations from the automotive chassis to minimize any adverse effects on the human body. In response to the issue of inadequate vibration isolation within multiple frequency bands for car seats, which can lead to discomfort for passengers, a vibration-damping seat structure equipped with an eddy current damper using electromagnets as the magnetic field source is proposed, and its vibration suppression characteristics are studied. First, a semi-active suspension damping structure is designed based on an eddy current damping effect. Second, the theoretical model of the semi-active suspension damping structure based on an eddy current effect is established, and the characteristic parameters of adjustable damping and their relationship with the amplitude response are analyzed. Finally, electromagnetic simulation analysis is conducted, and the results are compared with the theoretical model analysis results to verify the analysis, and the vibration suppression law of the semi-active suspension damping structure based on an eddy current effect is explored. Full article

To address the increasing demand for sustainable manufacturing in the automotive industry, this study focuses on the optimization of stamping process parameters for heavy truck seat reinforcement plates. Finite element analysis software and AutoForm R7 were utilized to develop a numerical simulation model for the stamping process, aiming to enhance material utilization and reduce waste. The research aimed to predict forming defects and explore the effects of blank holder force, friction coefficient, and drawbead resistance coefficient on springback, wrinkles, and strain, with an emphasis on improving production efficiency and minimizing resource consumption. The forming quality was optimized through adjustments in blank holder force, friction coefficient, and drawbead resistance coefficient, demonstrating the potential for eco-friendly manufacturing. Multi-objective optimization was performed to identify the optimal parameter combination, achieving sustainable outcomes with improved forming precision and reduced material waste. Results revealed that the optimal parameter combination (A4B4C2) included a blank holder force of 500 kN, a friction coefficient of 0.18, and a drawbead resistance coefficient of 0.25. These settings minimized material thinning (11.6%), excessive thickening (7.4%), and springback (0.905 mm), aligning with sustainable production standards. Full article

Induction-based breathing sensors in automobiles enable unobtrusive respiratory rate monitoring as an indicator of a driver’s alertness and health. This paper introduces a quantitative method based on signal quality to guide the integration of textile inductive electrodes in automotive applications. A case study with a simplified setup illustrated the ability of the method to successfully provide basic design rules about where and how to integrate the electrodes on seat belts and seat backs to gather good quality respiratory signals in an automobile. The best signals came from the subject’s waist, then from the chest, then from the upper back, and finally from the lower back. Furthermore, folding the electrodes before their integration on a seat back improves the signal quality for both the upper and lower back. This analysis provided guidelines with three design rules to increase the chance of acquiring good quality signals: (1) use a multi-electrode acquisition approach, (2) place the electrodes in locations that maximize breathing-induced body displacement, and (3) use a mechanical amplifying method such as folding the electrodes in locations with little potential for breathing-induced displacement. Full article

Background: The primary flame retardants in vehicles, organophosphates (OPEs) and polybrominated diphenyl ethers (PBDEs), volatilize and accumulate in the enclosed vehicle environment, posing potential health risks. Amidst the rising number of vehicles, the scrutiny of persistent organic pollutants like OPEs and PBDEs in vehicles is increasing. This study investigates occupational and nonoccupational population exposure to specific OPEs (TnBP, TBOEP, TEHP, TCEP, TCiPP, TDCiPP, TPhP, EHDPP) and PBDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, BDE-209) in vehicle dust. Methods: Data on OPEs and PBDEs in vehicle dust were sourced from PubMed and Web of Science. We applied PCA and PMF to identify pollutant sources and assessed health risks using the hazard index (HI) and carcinogenic risk (CR) methods. Monte Carlo simulations were conducted for uncertainty analysis, evaluating variable contributions to the results. Results: The predominant OPE in dust samples was TDCiPP (mean value: 4.34 × 10⁴ ng g⁻¹), and the main PBDE was BDE-209 (mean value: 1.52 × 10⁴ ng g⁻¹). Potential sources of OPEs in vehicle dust include polyvinyl chloride (PVC) upholstery, polyurethane foam (PUF) seats, electronics, carpet wear, hydraulic oil, and plastic wear in the brake system. PBDE sources likely include automotive parts, PVC upholstery, seats, carpets, and electronics. The 90th percentile HI and CR values for occupational and nonoccupational populations exposed to OPEs and PBDEs indicate that the noncarcinogenic and carcinogenic risks are relatively low. A sensitivity analysis showed that the pollutant concentration, time in the vehicle, exposure frequency, and duration significantly influence health risks. Conclusions: The health risks to both occupational and nonoccupational populations from exposure to OPEs and PBDEs in vehicle dust are relatively low. Full article

As the market share of electric vehicles continues to rise, consumer demands for comfort within the vehicle interior have also increased. The noise generated by electric seats during operation has become one of the primary sources of in-cabin noise. However, the offline detection methods for electric seat noise severely limit production capacity. To address this issue, this paper presents an online quality inspection system for automotive electric seats, developed using LabVIEW. This system is capable of simultaneously detecting both the noise and electrical functions of electric seats, thereby resolving problems associated with multiple detection processes and low integration levels that affect production efficiency on the assembly line. The system employs NI boards (9250 + 9182) to collect noise data, while communication between LabVIEW and the Programmable Logic Controller (PLC) allows for programmed control of the seat motor to gather motor current. Additionally, a supervisory computer was developed to process the collected data, which includes generating frequency and time-domain graphs, conducting data analysis and evaluation, and performing database queries. By being co-located with the production line, the system features a highly integrated hardware and software design that facilitates the online synchronous detection of noise performance and electrical functions in automotive electric seats, effectively streamlining the detection process and enhancing overall integration. Practical verification results indicate that the system improves the production line cycle time by 34.84%, enabling rapid and accurate identification of non-conforming items in the seat motor, with a detection time of less than 86 s, thereby meeting the quality inspection needs for automotive electric seats. Full article

Lower back pain (LBP) is one of the most prevalent health losses in adults worldwide. Historically, heat has been successfully used for treating pain and relieving tight muscles. Given the effective contact with the occupant’s back and proximity to the heat source, coupled with increasing commute times, automotive seats offer an opportunity to intervene. Fifteen adults (nine female) who experienced acute, subacute, and chronic lower back pain were recruited to examine the effectiveness of heat delivered to the lower back in providing temporary pain relief. Participants sat in a car seat for 38 min on two days, which included a 5-min baseline followed by a 33-min intervention; control, or localized. For the control condition, participants sat for 33 min without any thermal devices on, while the localized condition heated and maintained the seat surface temperature of the lower seat back area to ~45 °C. Over the 33-min control condition, the back skin temperature increased by ~1–2 °C and did not impact the subjective LBP. Heating the lower back for 33 min to ~39 °C reduced the subjective LBP by 10%. We demonstrated that lower back pain can be alleviated from an automotive seat providing heat to the lower back within normal commute times in those with lower back pain. Full article