Ride Comfort Research Articles

Uncertainty Optimization of Vibration Characteristics of Automotive Micro-Motors Based on Pareto Elliptic Algorithm

The NVH (Noise, Vibration, and Harshness) characteristics of micro-motors used in vehicles directly affect the comfort of drivers and passengers. However, various factors influence the motor’s structural parameters, leading to uncertainties in its NVH performance. To improve the motor’s NVH characteristics, we propose a method for optimizing the structural parameters of automotive micro-motors under uncertain conditions. This method uses the motor’s maximum magnetic flux as a constraint and aims to reduce vibration at the commutation frequency. Firstly, we introduce the Pareto ellipsoid parameter method, which converts the uncertainty problem into a deterministic one, enabling the use of traditional optimization methods. To increase efficiency and reduce computational cost, we employed a data-driven method that uses the one-dimensional Inception module as the foundational model, replacing both numerical models and physical experiments. Simultaneously, the module’s underlying architecture was improved, increasing the surrogate model’s accuracy. Additionally, we propose an improved NSGA-III (Non-dominated Sorting Genetic Algorithm III) method that utilizes adaptive reference point updating, dividing the optimization process into exploration and refinement phases based on population matching error. Comparative experiments with traditional models demonstrate that this method enhances the overall quality of the solution set, effectively addresses parameter uncertainties in practical engineering scenarios, and significantly improves the vibration characteristics of the motor.

Perceived Traffic Risk on Road Infrastructure Conditions among Car Drivers in Lhokseumawe City, Aceh, Indonesia

According to the Indonesian Department of Transportation, 86% of traffic accidents are attributed to human factors. Additionally, road conditions are identified as a contributing factor to road accidents. Therefore, this study aimed to explore road conditions and their impact on the driving behaviour of car drivers. Data for this exploration were collected by distributing questionnaires to 200 respondents, utilizing a Likert scale for answer options. The technique used was random sampling, utilizing descriptive statistical analysis and a Confirmatory Factor Analysis model. Consequently, the result showed that each latent variable construct examined by car drivers had a value exceeding 80%. The most prominent latent variable was the "Condition of Road Surface Facilities," accounting for 88.1% and featuring eight indicators. The indicator "Disturbed when passing through a narrow road," part of the latent variable "Condition of Road Equipment Facilities," had the highest standardized value at 1.223. Finally, this study suggested that the government should prioritize attention to road infrastructure conditions to enhance driver comfort and mitigate the risk of traffic accidents.

Numerical Prediction of Ride Comfort of Tracked Vehicle Equipped with Novel Flexible Road Wheels

Enhancing ride comfort has always constituted a crucial focus in the design and research of modern tracked vehicles, heavily reliant on the driving system’s performance. While the road wheel is a key component of the driving system, traditional road wheels predominantly adopt a solid structure, exhibiting subpar adhesion performance and damping effects, thereby falling short of meeting the demands for high-speed, stable, and long-distance driving in tracked vehicles. Addressing this issue, this paper proposes a novel type of flexible road wheel (FRW) characterized by a catenary construction. The study investigates the ride comfort of tracked vehicles equipped with flexible road wheels by integrating finite element and vehicle dynamic. First, three-dimensional (3D) finite element (FE) models of both flexible and rigid road wheels are established, considering material and contact nonlinearities. These models are validated through a wheel radial loading test. Based on the validated FE model, the paper uncovers the relationship between load and radial deformation of the road wheel, forming the basis for a nonlinear mathematical model. Subsequently, a half-car model of a tracked vehicle with seven degrees of freedom is established using Newton’s second law. A random road model, considering the track effect and employing white noise, is constructed. The study concludes by examining the ride comfort of tracked vehicles equipped with flexible and rigid road wheels under various speeds and road grades. The results demonstrate that, in comparison to the rigid road wheel (RRW), the flexible road wheel enhances the ride comfort of tracked vehicles on randomly uneven roads. This research provides a theoretical foundation for the implementation of flexible road wheels in tracked vehicles.

Determination of riding comfort on cycleways using a smartphone application

Well maintained cycleways will encourage more people to cycle, as the condition of cycleways is important for the safety, accessibility and riding comfort of cyclists. Despite that, only a few models used to describe the quality of service for cyclists take the surface condition into account. Objective measuring methods are needed to enable reliable and effective assessment of surface conditions, and measurable performance criteria related to the needs of cyclists should be developed. The purpose of this study has been to test the reliability and validity of using accelerometers in smartphones to assess the riding comfort on cycleways. A smartphone application converting three-dimensional accelerometer measurements into a single indicator for cycleways has been used to assess road surfaces in two field studies, in Sweden and Norway, respectively. Both studies assessed test sections of varying quality. To relate the measurements to subjective riding comfort assessments by cyclists, recruited cyclists collected quantitative data using the app, whilst also rating their perceived riding comfort by completing a survey. Measurements were also related to standard road surface condition indicators, generated from a road surface tester equipped with 19 laser sensors: international roughness index (IRI), mega- and macrotexture. The results show that it is possible to describe the unevenness of a cycleway using the technology present in smartphones. A software application can be used to collect and analyse data from the acceleration sensors in the phone, which can then be used to describe the riding comfort of cyclists. It is mainly the unevenness in the 50–1000 mm size-range that create the greatest discomfort for cyclists, and intermittent vibrations are perceived as more uncomfortable than more evenly distributed vibrations. Therefore, IRI is not a relevant measurement for describing the riding comfort of cyclists.

Autonomous Bus Docking for Optimal Ride Comfort of Standing Passengers

Autonomous Bus Docking for Optimal Ride Comfort of Standing Passengers

Analytical Investigation of Vertical Force Control in In-Wheel Motors for Enhanced Ride Comfort

This study explores the effectiveness of vertical force control in in-wheel motors (IWMs) to enhance ride comfort in electric vehicles (EVs). A dynamic vehicle model and a proportional ride-blending controller were used to reduce vertical vibrations of the sprung mass. By converting the state-space model into a transfer function, the system’s frequency response was evaluated using road profiles generated according to ISO 8608 standards and converted into Power Spectral Density (PSD) inputs. The frequency-weighted acceleration (aw) was calculated based on ISO 2631 standards to measure ride comfort improvements. The results showed that increasing the proportional gain (Kp) effectively reduced the frequency-weighted acceleration and the RMS of the vertical acceleration of the sprung mass. However, the proportional gain could not be increased indefinitely due to the torque limitations of the IWMs. Optimal proportional gains for various road profiles demonstrated significant improvements in ride comfort. This study concludes that advanced suspension technologies, including the proportional ride-blending controller, can effectively mitigate the challenges of increased unsprung mass in IWM vehicles, thereby enhancing ride quality and vehicle dynamics.

Modeling and Implementation of PID Controller in Vehicle Ride Comfort Improvement Using Bond Graph

The proportional integral derivative (PID) controller method is a famous and influential approach used in a variety of engineering domain systems. This paper presents Bond Graph modelling and implementation of PID controller in the active quarter-vehicle suspension system for the purpose of achieving better ride comfort. Bond graph is a better tool for modelling multi-domain energy systems with control hardware associated with it. SYMBOL SHAKTI software is used to simulate the active vehicle suspension system, which is theoretically represented as a 4-DOF human Bio-dynamic model combined with a 3-DOF quarter automobile system. The suggested PID Controller's performance is contrasted with that of the passive model. To measure the effectiveness of the suggested PID controller suspension system, time domain evaluations of systems performance criteria are conducted. The findings show that a significant improvement in ride comfort is offered by the suggested Bond graph PID controller model of the active vehicle suspension.

Evaluation of comfort zone boundary based automated emergency braking algorithms for car‐to‐powered‐two‐wheeler crashes in China

AbstractCrashes between cars and powered two‐wheelers (PTWs: motorcycles, scooters, and e‐bikes) are a safety concern; as a result, developing car safety systems that protect PTW riders is essential. While the pre‐crash protection system automated emergency braking (AEB) has been shown to avoid and mitigate injuries for car‐to‐car, car‐to‐cyclist, and car‐to‐pedestrian crashes, much is still unknown about its effectiveness in car‐to‐PTW crashes. Further, the characteristics of the crashes that remain after the introduction of such systems in traffic are also largely unknown. This study estimates the crash avoidance and injury risk reduction performance of six different PTW‐AEB algorithms that were virtually applied to reconstructed car‐to‐PTW pre‐crash kinematics extracted from a Chinese in‐depth crash database. Five of the algorithms include combinations of drivers’ and PTW riders’ comfort zone boundaries for braking and steering, while the sixth is a traditional AEB. Results show that the average safety performance of the algorithms using only the driver's comfort zone boundaries is higher than that of the traditional AEB algorithm. All algorithms resulted in similar distributions of impact speed and impact locations, which means that in‐crash protection systems likely can be made less complex, not having to consider differences in AEB algorithm design among car manufacturers.

Analisis Pengaruh Kenyamanan dan Kualitas Produk Terhadap Kepuasan Konsumen pada Motor Listrik PT. Len Industi (Persero) di Lingkungan Militer TNI.

The research aims to analyze the perception of comfort in driving electric motorcycles among TNI military personnel at PT. Len Industri (Persero) to identify factors influencing comfort and measure the impact of PT. Len Industri (Persero) electric motorcycle product quality on interest and satisfaction in the military environment. The study adopts a quantitative method, employing purposive sampling with a total sample of 40 respondents. Data collection involves distributing Likert scale questionnaires to consumers or TNI military personnel using PT Len Industri (Persero) electric motorcycles. The author employs data analysis techniques such as validity testing, reliability testing, normality testing, t-test, F- test, and R-test. The data obtained are processed using SPSS 29. Based on the results of the t-test, the calculated r-value is 5.323 > r-table 1.686, and a significant value of 0.00 < 0.05 is obtained, indicating that the related variables are influenced by independent variables. Referring to the coefficient of determination test results, an R square value of 86.7% is obtained. Thus, based on the analysis conducted, it is concluded that customer satisfaction is influenced by rider comfort and product quality.

Investigation of Different Windshield Designs for Aerodynamic Drag Force in Motorcycle

This research investigates the aerodynamic performance of different windshielddesigns for the Honda CB500X motorcycleat 140 km/h, focusing on drag force, drag coefficient, and pressure distribution. Three aftermarket windshields and oneoriginal equipment manufacturer(OEM)windshieldwere developed in SolidWorks and simulated using computational fluid dynamics (CFD) in ANSYS Fluent. The OEM windshieldoutperformed the aftermarket designs in terms of aerodynamic efficiency, with a lower drag force (735.65991 N) and drag coefficient (0.3951). However, apressure distribution study found that aftermarket windshields provided better deflection of airflow, resulting in less direct wind effect on the rider, potentially improving rider comfort and safety.These findings highlight the trade-off between aerodynamic efficiency and rider comfort in windshield design.

Lower Back & Comfortability Analysis of Driving Posture to Mitigate Musculoskeletal Disorders: An Ergonomics Study using Digital Human Modelling in JACK Software

In this paper, the crucial aspect of driver comfort was explored by investigating the prevailing driving postures among individuals, aiming to discern their ergonomic implications and ascertain whether the commonly adopted postures are conducive to musculoskeletal health or pose potential risks. From the last decade vehicle like cars have become one of the common modes of personal transport. Car has high relevance in day-to-day activities like commuting, economic activities and sports etc. The continuous driving of vehicle can lead the driver prone to musculoskeletal disorders such as back pain, spine injury and posture issues. This study is conducted to address the ergonomic aspects of posture of the driver to highlight the risk of Musculoskeletal disorders (MSDs) and to optimize the driving posture. Lower Back Analysis (LBA) and Comfortability Analysis is performed in JACK Software to analyze the driving posture. A DHM (Digital Human Model) is created in JACK Simulation Software according to the collected anthropometric data of an average Pakistani man. A virtual Environment is created in JACK Simulation Software. The posture of the subject is analyzed by taking measurements of the subject’s angle of joints when they are sitting in a driving posture. For Ergonomic Analysis the Driving Posture is evaluated on JACK software to Mitigate Musculoskeletal Disorders. Results show that the subject is having low back compression force of 672 which is below the NIOSH Back Compression Action Limit of 3400N representing a nominal risk of low back injury.

Statistical analysis of trends in Battery Electric Vehicles: Special reference to vehicle weight reduction, electric motor, battery, and interior space dimensions

Electric vehicles (EVs) are increasingly being used, as they are more environmentally friendly than conventional vehicles with internal combustion engines (ICE). Battery electric vehicles (BEVs) can be said to have zero exhaust emissions only if the electricity used to drive these vehicles is obtained in an environmentally friendly way. It is common knowledge that BEVs have a significantly higher overall mass than conventional vehicles. The significantly higher total vehicle weight of BEVs can have various adverse effects on energy consumption during movement and the vehicle's dynamics. In contrast to the negative aspects of BEVs, there are also positive aspects that are primarily related to the comfort of drivers and passengers, considering the main fact that they do not require the presence of a floor tunnel. In this paper, trends related to BEVs in the previous five years were statistically analysed. Changes in average sizes related to BEVs are shown, primarily internal dimensions that can be of crucial importance when deciding between BEVs and conventional vehicles. In the paper itself, other important trends are presented, both for the electric motor itself and for the batteries used in BEVs.

Modeling of Car-to-motorcycle Overtaking Maneuver Based on Comfort Zone Boundaries

Thailand has one of the world's highest road fatality rates, mainly on motorcycles. In mixed traffic, motorcycles coexist with other vehicles. The interaction between cars and motorcycles, such as overtaking due to speed differences, can lead to accidents. This scenario also has implications for autonomous vehicles interacting with motorcycles. To increase safety in such interactions, a model was developed that simulates overtaking maneuvers of car drivers with motorcycles, using the concept of comfort zone boundary and a four-phase classification. In a driving simulator, 648 overtaking maneuvers collected from 36 Thai drivers were recorded with different lateral positions and speeds of the motorcycles. A novel graphical method using steering wheel angle and steering wheel velocity signals facilitated the identification of the phases. Time-to-collision and lateral distance characterized driver comfort zones and served as an indicator for safety measures. The lateral position of the motorcycle has proven to be the most influential factor in the model. The results suggest that overtaking vehicles exhibit non-lane-bound driving characteristics and a risk for the sideswipe accident is identified. These results provide a foundational framework for advanced driver assistance systems and motion planning of autonomous vehicles, contributing to improved road safety.

Human-bus-road coupled vibration considering effect of braking forces

The ride comfort of vehicles traveling on the road has always been a concern. In addition, the braking force of vehicles will aggravate the damage to road structures and reduce the comfort of drivers and passengers. In the present study, the dynamic response of pavement, road friendliness, and human comfort are investigated by setting up the human-bus-road coupled vibration system considering the braking forces. Firstly, the three-dimensional finite element model of asphalt pavement with interlayer contact and the human-bus model with multiple degrees of freedom (2n + 7) were established to analyze the dynamic responses of asphalt pavement, human body, and bus under different braking conditions. Then, the dynamic load coefficients of wheels under different combined conditions were investigated to evaluate the road friendliness and the human annoyance rate was adopted to evaluate the human comfort. The results show that for the asphalt pavement, the shear stress of the pavement is larger than the normal stress due to the bus braking, and the combined effect of road surface roughness and braking force on the road friendliness is the largest. For the human comfort, the pitch acceleration of human body increases more than the roll acceleration due to bus braking, resulting in the decreased human comfort and increased annoyance rate.

Determination of Equine Behaviour in Subjectively Non-Lame Ridden Sports Horses and Comparison with Lame Sports Horses Evaluated at Competitions.

The Ridden Horse Pain Ethogram (RHpE) was developed to facilitate the identification of musculoskeletal pain. The aim of the current study was to collate behavioural data using the RHpE from horses at competitions assumed by their owners and/or riders to be fit for competition. The objectives were to quantify the frequency of occurrence of behaviours in pain-free horses and those with lameness or abnormalities of canter and to determine any differences between disciplines and levels of competition. The RHpE was applied to 1358 horses competing in Grand Prix (GP) dressage (n = 211), 5* three-day events (TDE) (n = 137), or low-level one-day events (ODE) (n = 1010). The median RHpE score for all horses was 4 (interquartile range [IQR] 2, 5; range 0, 12) and the median lameness grade was 0 (IQR 0, 1; range 0, 4). The Kruskal-Wallis test, followed by Dunn's test for pairwise comparisons, found a difference in median RHpE scores between low-level ODE and GP dressage (p = 0.001), but not between 5* TDE and low-level ODE (p = 0.09) or between GP dressage and 5* TDE (p = 1.00). The median RHpE score was highest for low-level ODE. The Chi-square/Fisher's exact test identified a significant difference in prevalence of most of the 24 behaviours of the RHpE in non-lame compared with lame horses. Recognition of the behaviours of non-lame horses may improve equine welfare and performance, and rider comfort, confidence, and safety.

Good practices on transit operation design: bus drivers’ perspective

Understanding which aspects can have the greatest influence on the performance, comfort and safety of a public transport system can be of great help in improving its operation and promoting more sustainable mobility. To find out more about these aspects, a survey was carried out among more than 180 drivers of urban bus transport systems in seven medium-sized cities in Spain. The drivers' perspective has been insufficiently taken into account in previous research, despite the fact that these workers have a high and direct knowledge of the operation and problems directly affecting the service. The data collected through this survey have been analysed using descriptive statistics and an Ordered Probit model. The results have allowed us to detect specific aspects to improve the performance and comfort of users and drivers such as the correct location and length of bus stops and enforcing regulation to ensure that buses have priority in traffic and that illegal parking does not interfere with their operations. In addition, bus lanes were seen as important by drivers to improve the comfort and safety of the service. Other factors related to safety were generally highly rated and there was little dispersion in the responses about their importance, although aspects such as proper visibility, avoiding illegal parking, and campaigns to encourage bus users to be aware of their surroundings stood out in the answers. Finally, the payment system was highlighted as very relevant to ensure the performance and comfort of users and drivers during the operation at bus stops. Improving this system was identified as the measure that could have the greatest impact on the performance of the service as a whole.

Who are the early adopters of alternative fuel technology? A study of Swedish road freight companies

This study investigates the effect of three key firm characteristics (diversification, size, and age) on road freight companies’ early adoption of alternative fuel vehicles (AFVs). While previous studies have identified the determinants of the adoption intention of AFVs, a gap in the literature is research into firm characteristics and the early adopters of AFVs. Because early adopters play an important role in the diffusion of innovation, it is imperative to fill this gap. Based on a survey of 156 Swedish road freight companies and logistic regression analyses, we report that firm size and diversification affect the early adoption of AFVs. In addition, the partial impact of the importance of driver comfort and payload capacity on early adoption of AFVs has been reported. Other factors, including purchase price, fuel cost, and truck refueling efficiency, were not found to discriminate early adopters of AFVs from those who had not yet adopted AFVs. These findings imply to policymakers that the current instruments in use in Sweden, including the greenhouse gas mandate and the relatively high taxation on diesel fuel, have led to the adoption of AFVs by larger road freight companies. For vehicle producers aiming to scale up the production and sales of AFV, the findings suggest the benefit of targeting diversified and larger road freight companies in the first place.

Whole body vibration and rider comfort determination of an electric two-wheeler test rig

Background Two-wheeled vehicles are the major mode of transportation in India. Such vehicles are exposed to excessive vibration on the road when compared to four-wheeled vehicles. However, the research on the reduction of whole body vibration in the case of two-wheelers is not explored in detail. The present study predicts rider comfort in the case of an electric two-wheeler as per ISO 2631-1, by obtaining the finding the weighted acceleration at the strategic locations of vibration at the test rig. Methods An electric two-wheeler test rig is used in the study. The values of acceleration from the test rig in running conditions are obtained by using NI LabVIEW 2019. The drive cycle of the electric vehicle (EV) test rig is controlled by Sync sols’ EV lab software. Obtaining the weighted root mean square (RMS) acceleration from running the test setup, it is compared with the ISO 2631-1 standard to obtain the rider comfort. Results Loading area, traction motor, base mount, and suspension were found to be the strategic points of vibration. Frequency weighted RMS acceleration of 0.3 to 0.4 m/s2 obtained at these points are prone to cause discomfort for the rider. Vehicle speed, road profile, and duration of exposure were found to be important parameters affecting the rider’s comfort. A maximum of 4.6 m/s2 amplitude was observed. The loading area, which corresponds to a rider’s seat in actual vehicle, is important and reduction of these vibrations make the ride comfortable for the rider. Suspension and base mount of the test rig are found to be uncomfortable observing the weighted RMS acceleration. Conclusions A suitable damping technique design is very much essential in reducing these vibrations and improve the rider comfort, as many more non-deterministic vibrations are prone to cause dis-comfort in case of actual on road riding conditions.

Ride comfort improvement by back propagation-active disturbance rejection control in semi-active hydro-pneumatic suspension of mining dump truck

Ride comfort improvement by back propagation-active disturbance rejection control in semi-active hydro-pneumatic suspension of mining dump truck

Biomechanics‐based study of muscle activation under different driving conditions for Chinese percentiles

AbstractIn this paper, we determined the adjustment levels of the human–machine layout under the preferred driving posture for individuals with different body sizes. We also comparatively analyzed the maximum activation levels of various muscles under straight‐line driving and steering conditions. To increase the accuracy of the results, AnyBody biomechanics software was used to establish a human skeletal muscle mechanics model, which we analyzed for consistency with rig test results. The results showed that people with larger body sizes preferred a driving position with the seat reclined back. Steered driving was associated with a significant (p < .05) increase in the maximum activation of the wrist extensors, serratus anterior, deltoid, and triceps brachii, which are the main force‐generating muscle groups for steered driving, compared with straight driving. Moreover, the measured and simulated results of maximum muscle activation were relatively consistent, with the error between them within a 15% margin. In summary, this study explored the relationship between different driving conditions and preferred driving postures from a biomechanical perspective. A combined experimental and simulation approach was adopted to ensure the reliability of the findings. The insights from this study can inform ergonomic considerations for the comfort and health of Chinese drivers with varying physical characteristics.