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In human walking, the left and right legs move alternately, half a stride out of phase with each other. Although various parameters, such as stride frequency and length, vary with walking speed, the antiphase relationship remains unchanged. In contrast, during walking in left-right asymmetric situations, the relative phase shifts from the antiphase condition to compensate for the asymmetry. Interlimb coordination is important for adaptive walking and we expect that interlimb coordination is strictly controlled during walking. However, the control mechanism remains unclear. In the present study, we derived a quantity that models the control of interlimb coordination during walking using two coupled oscillators based on the phase reduction theory and Bayesian inference method. The results were not what we expected. Specifically, we found that the relative phase is not actively controlled until the deviation from the antiphase condition exceeds a certain threshold. In other words, the control of interlimb coordination has a dead zone like that in the case of the steering wheel of an automobile. It is conjectured that such forgoing of control enhances energy efficiency and maneuverability. Our discovery of the dead zone in the control of interlimb coordination provides useful insight for understanding gait control in humans. Analyses of the synchronization mechanism between the legs during walking using two coupled oscillators and Bayesian inference method reveal the presence of a "dead zone," where the control of interlimb coordination is ineffective. [ABSTRACT FROM AUTHOR]

The high photoluminescence quantum yield (PLQY) orange-red phosphor, which is of great significance for the application of phosphor-converted light-emitting diode (LED). Herein, the novel BaSrLu 4 O 8 :Eu2+ orange-red phosphor was synthesized, and the PLQY is enhanced from 30 % to 91 % by Al 2 O 3 assisted sintering. Combined with the trap energy level analysis, it is considered that the addition of Al 2 O 3 introduces new vacancies, which release electrons during high temperature sintering, creating a more favorable environment for the reduction of Eu3+, increasing the Eu2+ luminescence center in the matrix and improving the PLQY. The white LED device prepared with BaSrLu 4 O 8 :Eu2+ and Y 3 (Al,Ga) 5 O 12 :Ce3+ has a color rendering index of 84.4 at a low correlated color temperature of 4295 K. Meanwhile, the luminous brightness of the orange LED prepared by BaSrLu 4 O 8 :Eu2+ can maintain 89 % of the original light intensity in the simulated foggy day illumination experiment, which proves its excellent lighting prospect as an automobile steering lamp in foggy and smog extreme conditions. The results indicate that this work provides a new strategy for the reduction of Eu2+ while realizing the multi-application of phosphors. [Display omitted] [ABSTRACT FROM AUTHOR]

Commercialized polyurethane foam products for automobile steering wheels have been committed to the development of products with comprehensive properties such as low density, high production efficiency and environmental protection. Based on this, this article has launched a series of experiments to explore the effects of different types of chain extenders, blowing agents and catalysts on the mechanical properties, cell structure, skin and reactivity of self-skinning polyurethane foams for automobile steering wheels. The results show that the hardness and tensile strength of the foam gradually decrease with the chain growth of small molecular chain extenders (ethylene glycol, 1.3-propanediol, 1.4-butanediol), and the elongation at break increases gradually. The foaming agent formic acid is more conducive than water as it favors the formation of small but compact cells, thus dense skin. The catalytic efficiency of non-reactive catalysts (A1, KC101 and DabcoEG) is higher than that of reactive catalysts (LED-103, ZR-50, DPA). The theoretical research for the development of high-performance and high-efficiency polyurethane foam products for automobile steering wheels. [ABSTRACT FROM AUTHOR]

The main parts of automobiles are the piston rod of the shock absorber and the steering rack of the steering gear, and their quality control is critical in the product process. In the process line, these products are normally inspected through visual inspection, sampling, and simple tensile tests; however, if there is a problem or abnormality, it is difficult to identify the type and location of the defect. Usually, these defects are likely to cause surface cracks during processing, which in turn accelerate the deterioration of the shock absorber and steering, causing serious problems in automobiles. As a result, the purpose of this study was to present, among non-destructive methods, a shock response test method and an analysis method that can efficiently and accurately determine the defects of the piston rod and steering rack. A test method and excitation frequency range that can measure major changes according to the location and degree of defects were proposed. A defect discrimination model was constructed using machine and deep learning through feature derivation in the time and frequency domains for the collected data. The analysis revealed that it was possible to effectively distinguish the characteristics according to the location as well as the presence or absence of defects in the frequency domain rather than the time domain. The results indicate that it will be possible to quickly and accurately check the presence or absence of defects in the shock absorber and steering in the automobile manufacturing process line in the future. It is expected that this will play an important role as a key factor in building a smart factory. [ABSTRACT FROM AUTHOR]

Cold forging dies are manufactured through the shrink fit process to withstand high pressure loads, but fatigue failure eventually occurs due to repeated compressive stresses. The life cycle until fatigue failure was defined as the limit life, and attempts were made to predict the die life based on finite element method. However, accurate prediction was impossible owing to uncontrollable environmental variables. Consequently, it is impossible to clearly determine the die replacement cycle, resulting in negative consequences such as poor quality, production delay, and cost increase. Various environmental factors affecting the prediction of die life cycle result in the increase or decrease of the forming load, which is an important variable that determines the die life cycle. In this study, a system for monitoring load data generated from forging facilities was developed based on a piezo sensor. In addition, the die life cycle was more accurately predicted by using the forming load data measured in real time, and a die life management system that can determine the die replacement cycle was applied to the automobile steering parts production line. [ABSTRACT FROM AUTHOR]

Monotony, caused by deficiencies in the visual reference, can increase the risk of road accidents. This paper focuses on using landscape intervention as an alertness maintaining 'tool' to counter monotony. Therefore, a driving simulator experiment with four different scenes was designed. One is the control group with no landscape. The other three are landscapes with different spatial patterns. The spatial patterns were treatments combing the different graphic shapes and different enclosure degrees. Twenty‐six subjects were required to drive in the centre of the right lane with a speed limit of 80 km/h as an alertness task. To assess the impact of different landscapes on driving behaviour, speed, steering wheel angle, and lane position were analysed. The results indicated a significant advantage of alertness maintaining of semi‐open chevron landscape. Speeding and lane crossing has been significantly improved (p < 0.05). Also, the adequate length of the semi‐open chevron landscape based on the alertness threshold of steering wheel angle SampEn is longer than the other spatial patterns. This work can help to develop more efficient monotony countermeasures with landscape intervention. It also provides valuable information for methods of adequate duration determination in alertness maintaining 'tool' based on driving behaviour. [ABSTRACT FROM AUTHOR]

In order to improve the handling stability of four-wheel steering (4WS) cars, a two-degree-of-freedom 4WS vehicle dynamics model is constructed here, and the motion differential equation of the system model is established. Based on the quadratic optimal control theory, the optimal control of 4WS system is proposed in this paper. When running at low speed and high speed, through yaw rate feedback control, state feedback control, and optimal control, the 4WS cars are controlled based on yaw rate and centroid cornering angle with MATLAB/Simulink simulation. The result indicates that 4WS control based on the optimal control can improve the displacement of the cars. And, the optimal control of 4WS proposed in this paper can eliminate centroid cornering angle completely compared with other two traditional optimal control methods. Besides, the optimal control enjoys faster response speed and no overshoot happens. In conclusion, the optimal control method proposed in the paper represents better stability, moving track and stability, thereby further enhancing the handling property of cars. [ABSTRACT FROM AUTHOR]

The APM 300 running gear structure follows the structural design of the automobile steering drive axle; therefore, the lateral stiffness of the suspension system is considerable, resulting in poor lateral ride comfort. To improve the lateral ride comfort of the vehicle, this paper proposed a new type of running gear called single air spring running gear (SARG), and according to the original loading conditions, the parameters of the SARG air spring are modified. By establishing a theoretical model of linear steady-state curve negotiation of the single-axle tyre running gear, the radial adjusting index is deduced to evaluate the radial performance of the SARG. By establishing the force analysis model of APM rolling in the static state, APM's flexibility coefficient is obtained to evaluate the anti-overturning capacity. The influence of running gear parameters on the flexibility coefficient is discussed in detail. Based on this, the stiffness of the SARG anti-roll bar is determined. By comparing the dynamic performance of both types of vehicles, the SARG advantages are proved. Finally, several improvements on the SARG structure are proposed for its adaptation to more complex scenario. [ABSTRACT FROM AUTHOR]

The traditional lane change warning method is time-consuming and low success rate. A lane change warning method based on radar ranging is proposed. Based on the principle of Doppler radar, the distance between static vehicle and dynamic vehicle around the target vehicle is judged and measured. According to the lane line coordinate parameters, the distance between the target vehicle and the left and right lane lines is calculated, and the vehicle turning and lane changing time is calculated by combining the speed and road condition information at this time. If the lane change time is longer than the safety threshold time, the lane change warning is enabled. Experimental results show that the method has a high success rate of early warning, with an average success rate of 98.22%. [ABSTRACT FROM AUTHOR]

When driving a 32‐m long multi‐set rubber‐tire transit in a manual driving mode, it is easy for the driver to feel tired due to the massive concentration, and it is hard to manually operate in a narrow and twist gauge. The authors introduce a six‐axle coordinated automatic all‐wheel steering control system and its design method is based on the visual perception and the geometric relationship. First, the functions of the two subsystems of the full‐axle automatic steering control system are introduced. One subsystem is a path tracking control system and the other subsystem is a trajectory following the control system. Secondly, the theoretical principles of the two control systems are introduced in detail. Then, the controller design method of the two subsystems is introduced. Finally, the simulation results of Trucksim and MATLAB/Simulink are compared with the actual vehicle test data to test the controller's perception and the follow‐up control effect. It can be concluded that the gap between the platform and the train is kept between a relatively 10∼20 cm narrow when the train pulls in and out of the station. When the train runs at a high speed, it is stabilised at 72 km/h, and the lateral deviation from the virtual track centreline is controlled within ±15 cm. [ABSTRACT FROM AUTHOR]

An important part of the overall task of social and economic development of many developed countries is the creation of a unique transport infrastructure or improvement of transport services for the population. The cumulative solution to many problems is to improve the quality and reliability of elements and equipment in any vehicle design. This determines its efficient operation and the safety of passengers. A common urban electric transport in megacities is a trolleybus, the reliability of which depends on individual components and assemblies, power supply systems and traffic control. But this type of transport requires modern scientific and technical solutions for the design of individual components and assemblies, for example, steering, which is directly related to the safe and comfortable transportation of passengers. An innovative technical solution has been proposed that will increase the energy efficiency of the trolleybus steering system through the use of an electric power steering based on a rolling rotor electric motor. The analysis of the design is carried out and the principle of control of the rolling rotor motor is determined. Functional diagrams of the components of the trolleybus steering system with an electric power steering based on a rolling rotor motor are developed. The electromagnetic and mechanical connections of the motor with the rolling rotor are determined and mathematically described. Factors affecting the steering system when turning the steered wheels are reasoned. A mathematical model of a trolleybus steering system with an electric booster based on an electric rolling rotor motor has been developed. The mathematical model is based on the differential equations of the electrical and mechanical parts. Algebraic equations were used to characterize the electromagnetic connections of the rolling rotor motor. The proposed solution will allow simulating dynamic processes in the trolleybus steering system and evaluating the results. Determination of the efficiency of the steering system was carried out by comparative analysis of the following factors: the control action created by the driver, the condition of the road surface, dynamic and transient electromechanical processes of the system, and the like. [ABSTRACT FROM AUTHOR]

Summary. Steering systems are one of the most important components of a car and have a direct impact on safety and driving comfort. Therefore, high reliability is required of them. One of the methods of object reliability estimation may be the grey system theory. This method can be used not only to calculate the number of failures, but also to calculate the wear of mating parts, and the vibrations of engines and rolling elements. This work presents the use of the grey system theory for the examination of motor vehicle steering system reliability. The forecast number of failures was calculated for the various components of the steering system and the grey system accuracy was assessed. This is aimed at finding out how useful this theory is for forecasting the number of steering system failures. [ABSTRACT FROM AUTHOR]

The torque developed in the steering system of an automobile is a result of multiple interactions between a tyre and the roadway surface. Models are well established for high-speed ground vehicle operation where the tyre is rolling rapidly and the dominant source of tire tread stress is deformation due to lateral force on the tyre. In contrast, for situations where the vehicle is operating at low speeds or even steering when stationary, the torque required to turn the wheels is predominantly a function of the steering rate. However, the torque still can be predicted using models of the deformation of the tyre rubber. This paper introduces such a model of the tyre dynamics that considers the low-speed tyre deformation behaviour considering the interacting effects of steering while the tyre is slowly rolling, allowing for the prediction of steering torques during low speed manoeuvring. The physics-based model is validated with steering torque data from an instrumented steer-by-wire vehicle. The validated model also allows for opportunistic friction estimation in certain steady conditions by inversion of the model with the steering rate, steering torque, and vehicle speed as input data. [ABSTRACT FROM AUTHOR]

Automobile steering knuckle is an important part of the steering system, which is subjected to significant impacts and loads during its operation. Generally, cast aluminum steering knuckles are usually produced using some type of enhanced low-pressure casting process, like counter-pressure casting. Compared with aluminum forging and sand cast ductile iron, it can improve the production speed and achieve the adequate casting quality. In this study, various methodologies such as dynamic thermomechanical analysis, differential scanning calorimetry, and the laser flash method were employed to study the thermophysical properties of AlSi7Mg0.3. Further, the physical model of a counter-pressure casting system with an aluminum interior was established based on the combination of the tested and the theoretical properties of aluminum; this was achieved with the consideration of the presence of other factors including rapid solidification. The temperature field of the system was computed and verified by thermocouples at six different points during the tooling and the shrinkage simulation. It was observed that the plot shape of the computed temperatures and that of the simulated ones correlated; further, the difference between the peaks and the valleys was controlled to be 3% on an average, with the maximum variation of 7% at only one point. Moreover, all the predicted shrinkages were verified by the casting. This study provides a solid foundation for facilitating the simulation of the morphologies of the microstructure. [ABSTRACT FROM AUTHOR]

Recently in many cities of the world began to introduce so-called «metrobus» or BRT (Bus Rapid Transit) systems, which became a cheaper alternative to the metro and other rail transport, in particular trams. The aim of the work is to determine the stability indicators of the metrobus in the transitional traffic modes, in particular when performing such manoeuvres as «steering wheel jerk» and «shuffle». For this purpose, the equations of metrobus plane-parallel motion are supplemented by equations of the links of the road train in the vertical plane by halopilation (tangage, trim) and roll. The critical straight-line speed of the three-link metrobus has been determined, which was 32,06 m/s, and this speed is independent of the corners of the steering wheels of the bus and the trailer links. It has been shown that as the steering wheel angle of the bus increases, the difference in the folding angles of the bus increases, with the second folding angle significantly exceeding the first, especially considering the roll of the metrobus body. It has been established that the greatest rolls and loads of the metrobus axles are those of the last trailer, which is the limiting factor for the critical speed. The lateral accelerations of individual metrobus links and their yaw velocity when performing the manoeuvre «steering wheel jerk» and «shuffle, Sl = 24 m», show that both the bus and the second trailer link are a limiting factor when performing various manoeuvres, but the acceleration value does not exceed the permissible 0.4 g, so its stability under these conditions is ensured. [ABSTRACT FROM AUTHOR]

The autodriver algorithm was introduced as a path-following algorithm for autonomous vehicles, which uses road geometry data and planar vehicle dynamics. In this paper, the autodriver algorithm is improved according to practical implications, and a more realistic vehicle model (roll mode) is used, which considers roll degree of freedom in addition to a planar motion. A Ghost-Car path-following approach is introduced to define the desired location of the car at every instance. Key steady-state characteristics of turning vehicles, namely the curvature, yaw rate, and side-slip responses, are discussed and used to construct a feed-forward component of a path-following controller based on the autodriver algorithm. Feedback control loops are designed and applied to minimise transient errors between the road and vehicle positions. Finally, simulations are performed to analyse the pathfollowing performance of the proposed scheme. The results show promising performance of the controller both in terms of error minimisation and passenger comfort. [ABSTRACT FROM AUTHOR]

Statistical model improvement consists of model calibration, validation, and refinement techniques. It aims to increase the accuracy of computational models. Although engineers in industrial fields are expanding the use of computational models in the process of product development, many field engineers still hesitate to perform statistical model improvement due to its practical aspects. Therefore, this paper describes research aimed at addressing three practical issues that hinder statistical model improvement in industrial fields: (1) lack of experimental data for quantifying uncertainties of true responses, (2) numerical input variables for propagating uncertainties of the computational model, and (3) model form uncertainties in the computational model. Issues 1 and 2 deal with difficulties in uncertainty quantification of experimental and computational responses. Issue 3 focuses on model form uncertainties, which are due to the excessive simplification of computational modeling; simplification is employed to reduce the calculation cost. Furthermore, the paper outlines solutions to address these three issues, specifically: (1) kernel density estimation with estimated bounded data, (2–1) variance-based variable screening, (2–2) surrogate modeling, and (3) a model refinement approach. By examining the computational model of an automobile steering column, these techniques are shown to demonstrate efficient statistical model improvement. This case study shows that the suggested approaches can actively reduce the burden in statistical model improvement and increase the accuracy of computational modeling, thereby encouraging its use in industry. [ABSTRACT FROM AUTHOR]

EDAS (EGNOS Data Access Service) is the EGNOS internet broadcast service, which provides free of charge access to the data collected and generated by the EGNOS infrastructure. EDAS disseminates over the Internet, both in real time and via an FTP archive, the raw data of the GPS, GLONASS (no commitment on GLONASS data is provided (1)) and EGNOS GEO satellites collected by the receivers located at the EGNOS reference stations, which are mainly distributed over Europe and North Africa. The EDAS services offer several types of GNSS data in various protocols and formats, such as DGNSS corrections. This paper reports on the results of some in-field tests conducted by ESSP and Topcon Agriculture to confirm the suitability of EDAS DGNSS corrections for precision farming in Europe. The European Commission (EC) is the owner of EGNOS system (including EDAS) and has delegated the exploitation of EGNOS to the European GNSS Agency (GSA). EDAS service provision is performed by ESSP, as EGNOS Services Provider, under contract with the GSA, the EGNOS program manager. In the ENC 2018 article "EDAS (EGNOS Data Access Service): Differential GPS corrections performance test with state-of-the-art precision agriculture system", ESSP and Topcon Agriculture presented the results of the first in-field test conducted in a dynamic and real-life environment in the summer of 2017. The test results indicated that the EDAS DGNSS corrections could enable a reliable pass-to-pass accuracy performance for a wide range of precision agriculture applications and become an attractive solution for cereal farms, when the farm is located in the vicinity of an EGNOS reference station. In particular, Topcon Agriculture acknowledged that the observed performance was sufficient to support the following precision agriculture applications: spraying and spreading of any crop type, tilling and harvesting of cereal. Then, ESSP and Topcon Agriculture engaged in additional testing activities to further characterise the EDAS DGPS performance in different scenarios (i.e. at various European locations and with a variety of distances between the designated farm and the target EGNOS reference station). In each test, multiple runs with the rover tractors have been performed over the reference patterns predefined in the Topcon guidance systems. Data recorded during the tests has been analysed in detail, looking at the key performance indicators (e.g. cross track error and pass-to-pass performance) that characterize the EDAS DGPS performance for precision agriculture applications. Different techniques for the computation of the pass-to-pass accuracy performance have been used, including a procedure to measure live in the field and a post-processing alternative. The diversity of scenarios available allows drawing conclusions on the applicability of EDAS DGPS corrections (in terms of maximum distance from the target EGNOS station) for precision agriculture and also understanding the impact of operationally relevant aspects such as the quality of the mobile internet coverage (highly variable across Europe). The EDAS system and its architecture, the main types of data disseminated through EDAS services and the online information available to the EDAS users are introduced in this paper. In particular, the EDAS Ntrip service is described in detail, since it provides the differential corrections to the GPS and GLONASS satellites at the EGNOS reference stations in RTCM format, which are the basis for the present study. The article also reports on the results of the latest tests, which have been performed using Topcon receivers, vehicles and auto-steering systems. In all cases, two different Topcon guidance systems on board tractors were running simultaneously to assess the EDAS DGPS positioning performance with respect to a the reference provided by a top-performing RTK-based Topcon solution. The objective of this paper is to draw conclusions on the use of EDAS DGPS corrections as a reliable free-of-charge alternative for precision farming in Europe (especially for cereal farms), based on the available performance results from the testing campaign and the feedback from the involved precision agriculture experts. [ABSTRACT FROM AUTHOR]

This study sought to investigate whether force perceptual bias was affected by differences in posture while steering an automobile using a psychophysical experiment to examine the relationship with muscle activity. The human perceptual characteristics of weight and force are known to be nonlinear, and a perceptual bias can occur, that is, bias that causes a perception of something that is larger or smaller than the actual scale. This is considered to be caused by physical and/or psychological conditions. Sense of effort is believed to be one influential factor. It is known to correlate with muscle activity intensity, and bias may be caused by muscle activity changes. In the current study, we hypothesized that force perceptual bias would depend on posture due to the intensity of muscle activity changes caused by changing postures during steering operation. By investigating this hypothesis, we can clarify the relationship between sense of effort and muscle activity. To investigate this issue, we conducted a psychophysical experiment to confirm postural dependence, and estimated muscle activity using a three-dimensional musculoskeletal model simulation with postural and arm force data during the experiment. In addition, prediction of bias was conducted based on a simulation in the psychophysical experiment using these data. The results revealed that bias existed, as measured by differences in postures. Additionally, a significant moderate correlation was found between the predicted bias and the actual bias, indicating the existence of a relationship between muscle activity and bias. [ABSTRACT FROM AUTHOR]

In this study, a computational fluid dynamics (CFD) model is developed to investigate die filling of semi solid slurry as part of rheo pressure die casting (RPDC) system. The die filling cavity corresponds to that of an automobile steering knuckle, and the slurry is made of A356 aluminium alloy. The rheological model used in the CFD simulation is determined experimentally. The results obtained from present numerical model includes flow field of the slurry within the die cavity, viscosity evolution, solid fraction distribution, temperature and pressure distribution during solidification within cavity during die filling stage. The main objective of the study is to determine the gating arrangement, pouring temperature, and injection conditions for desirable microstructure and mechanical properties of the developed component. To study the effect of injection conditions on die filling capability of the said alloy slurry, five injection profiles are studied, with a variation in final injection velocity between 2–3.2 m/s. In order to corroborate the findings of the present study, microstructural morphology and structure-property correlation have been studied, primarily in the form of optical microscopy and macro hardness measurements, by obtaining samples from different locations of the solidified component. [ABSTRACT FROM AUTHOR]

This paper presents a new approach for autonomous reversing of a tractor-semitrailer vehicle called minimum swept path control (MSPC). MSPC improves the performance of previous path following control (PFC) strategies, by minimizing the maximum excursion of the vehicle, while guaranteeing acceptable path following accuracy. A linear controller is devised, combining state feedback control with an optimized preview distance. A relationship between the maximum lateral offsets of the front axle of the tractor unit and the rear axle of the last trailer and the corresponding weights in the control cost function is established, and the controller is tuned to provide the best performance compromise. Several simulations of a tractor-semitrailer case are run, and the results show that the overall swept path width is reduced by more than 40% when compared with PFC methods. [ABSTRACT FROM AUTHOR]

In order to solve the contradiction between the control output and the control effect, especially in extreme conditions, this paper designs a H ∞ /extension controller based on active front steering system by introducing the extension control into H ∞ mixed sensitivity control about sensitivity function S/T problem. The proposed controller can transform the control information under the unstable domain into the eligible value range by using dependent degree to tune the control output. And ultimately, the combination of H ∞ norm and extension transformation extends the stable region of the system. The results of the simulation and vehicle test show that the proposed H ∞ /extension controller can effectively deal with the contradiction between the control effect and the control output under extreme condition, and achieve satisfactory control effect with the control output as small as possible under normal condition. [ABSTRACT FROM AUTHOR]

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Estimating vehicle sideslip angle and road friction in real time is of great significance for vehicle stability control and intelligent vehicle lateral control. These parameters are often difficult to obtain directly and the high cost of measuring instruments restricts their application in general vehicle control. Therefore, an estimation method based on online gradient descent (OGD) algorithm for vehicle sideslip angle and road friction is proposed. For the front-wheel-steer and front-wheel-drive vehicle, the vehicle's lateral dynamics model is established with smaller assumptions. And an unknown input observer is designed to estimate the tire's lateral force of the rear wheel. On the basis of this, the parameter estimation is transformed into the parameter optimization problem and the cost function is designed by using the nonlinear tire model, i.e., magic formula, and its gradient formula. Then, the OGD algorithm is used to estimate the sideslip angle and road friction, respectively. The effectiveness of the proposed method is evaluated via numerical simulation based on MATLAB/Simulink and CarSim software platform. The results show that the method can reliably and accurately estimate the vehicle sideslip angle and the road friction under a variety of test conditions. The proposed algorithm can effectively suppress the influences of sensor noise, longitudinal velocity change, and tire force nonlinearity on the estimation results. [ABSTRACT FROM AUTHOR]

• Micro-LSP is proposed to increase the wear resistance of AISI 5140 steel. • Micro-LSP increased the surface hardness, and decreased the friction coefficient and surface roughness. • The wear rate of specimens after Micro-LSP treatment is lower than that of LSP treatment. • Micro-LSP increased the resistance of the sample to foreign substance intrusion. AISI 5140 steel is widely used in automobile steering shafts, whereby its abrasion resistance directly affects the reliability of transmission components. This paper proposes Micro-laser shock peening (Micro-LSP) as a new laser shock peening (LSP) treatment. The surface of the AISI 5140 steel was examined after Micro-LSP, and its influence on the wear resistance was determined. Compared with LSP, Micro-LSP exhibited a better strengthening effect on the wear and surface hardness. After Micro-LSP treatment, the surface hardness of the sample was 368.7 HV 0.5 , the depth of the hardened layer was 580 μm, and the surface roughness was 1.40 μm. This improved wear resistance is attributed to the higher microhardness and formation of a surface oxide layer. [ABSTRACT FROM AUTHOR]

Our objective in this contribution is to categorize driver behavior in terms of preturning maneuvers. We analyze driving behavior in an urban environment prior to turns using data obtained from the CANbus of an instrumented vehicle during a one-hour driving period for 12 different individuals. CANbus data streams such as vehicle speed, gas pedal pressure, brake pedal pressure, steering wheel angle, and acceleration are collected and analyzed for 5, 10, and 15 seconds of driving prior to each turn. We consider all turns for each driver and extract statistical features from the signals and use cluster analysis to categorize drivers into groups reflecting different driving styles. The results show that using this approach we can effectively cluster drivers into two groups. The results show consistency in the membership within a cluster throughout the different timeframes. We conclude that driver behavior classification from such data streams is possible and we hope in the near future to devise driver descriptors that include additional maneuvers. [ABSTRACT FROM AUTHOR]

Highlights • Studies impacts of automated vehicles on the performance of freeway weaving sections. • Proposes a multiclass hybrid model including lane change positions as exogenous input. • Finds optimal lane change positions using simulation-based optimization. • Results show 15% capacity increase by optimizing the spatial lane change distribution. • Considering vehicle class dependent reaction times reveals a combination effect. Abstract Weaving sections, where a merge and a diverge are in close proximity, are considered as crucial bottlenecks in the highway network. Lane changes happen frequently in such sections, leading to a reduced capacity and the traffic phenomenon known as capacity drop. This paper studies how the emerging automated vehicle technology can improve the operations and increase the capacity of weaving sections. We propose an efficient yet effective multiclass hybrid model that considers two aspects of this technology in scenarios with various penetration rates: (i) the potential to control the desired lane change decisions of automated vehicles, which is represented in a macroscopic manner as the distribution of lane change positions, and (ii) the lower reaction time associated with automated vehicles that can reduce headways and the required gaps for lane changing maneuvers. The proposed model is successfully calibrated and validated with empirical observations from conventional vehicles at a weaving section near the city of Basel, Switzerland. It is able to replicate traffic dynamics in weaving sections including the capacity drop. This model is then applied in a simulation-based optimization framework that searches for the optimal distribution of the desired lane change positions to maximize the capacity of weaving sections. Simulation results show that by optimizing the distribution of the desired lane change positions, the capacity of the studied weaving section can increase up to 15%. The results also indicate that if the reaction time is considered as well, there is an additional combined effect that can further increase the capacity. Overall, the results show the great potential of the automated vehicle technology for increasing the capacity of weaving sections. [ABSTRACT FROM AUTHOR]

Highlights • An adaptive staircase to estimate drivers’ individual gap acceptance at junctions. • Drivers accept smaller (risker) gaps in front of motorcycles than cars. • Drivers do not modify their behaviour when clearing the junction. • Differences in gap acceptance were only found in the high-fidelity simulator. Abstract A disproportionate number of road deaths occur at intersections where one vehicle is a motorcycle. Previous research has not systematically varied the type of vehicles presented in a controlled environment. We compared drivers’ (n = 54) gap acceptance when either a car or motorcycle was approaching a junction. We used a QUEST adaptive staircase to estimate gap acceptance thresholds for cars and motorcycles separately. On each trial, drivers saw a car approaching from the left and a vehicle (car or motorcycle) approaching from the right. The driver had to stop for the car from the left, but could choose whether to pull out in front of the vehicle from the right, or to wait for it to pass. Participants completed the task in either a medium-fidelity simulator (steering wheel and pedals, 180-degree screen) or a high-fidelity simulator (fully instrumented car, 360-degree screen). Participants accepted significantly smaller (riskier) gaps in front of motorcycles than in front of cars, particularly in the high-fidelity simulator. The speed of crossing the junction did not differ between vehicle types, meaning that drivers were closer to the motorcycle than the car during the manoeuvre. There was one instance that appeared to replicate a ‘Look But Fail To See’ error, where a participant pulled out in front of an oncoming motorcycle resulting in a crash. This suggests that drivers accept riskier gaps around motorcycles than cars, which may be due to a difference in attitude towards different vehicles or differences in optic flow properties. These results help to explain the disproportionate involvement of motorcycles in real junction crashes. [ABSTRACT FROM AUTHOR]

Highlights • Automation changed the way drivers allocated attention when parallel parking. • Drivers glanced towards the parking space less when steering was automated. • Glances were redirected to the instrument cluster showing system information. • Drivers also looked at the instrument cluster while approaching a spot. Abstract Drivers adapt their glance behavior when using automation, which may detract attention from their surroundings. Glance behavior during parallel parking maneuvers performed with and without automated steering was compared. Drivers directed a smaller proportion of their glances toward the parking space and spent less time looking at it when using automation than when not using automation. The proportion of glances and time spent looking at the instrument cluster containing information from the automation increased significantly. Drivers also spent a significantly larger proportion of time looking at the instrument cluster and a smaller proportion looking forward and rearward when using automation while approaching a parking space. The system selected the parking space in the approach phase, which may have drawn attention to the instrument cluster. In conclusion, when using automated steering during parallel parking drivers monitored their surroundings less and looked at system displays more presumably to supervise the automation. The safety implications of these changes in glance behavior should be explored in future research. [ABSTRACT FROM AUTHOR]

A general and psychologically plausible collision avoidance driver model can improve transportation safety significantly. Most computational driver models found in the literature have used control theory methods only, and they are not established based on psychological theories. In this paper, a unified approach is presented based on concepts taken from psychology and control theory. The “task difficulty homeostasis theory”, a prominent motivational theory, is combined with the “Lyapunov stability method” in control theory to present a general and psychologically plausible model. This approach is used to model driver steering behavior for collision avoidance. The performance of this model is measured by simulation of two collision avoidance scenarios at a wide range of speeds from 20 km/h to 170 km/h. The model is validated by experiments on a driving simulator. The results demonstrate that the model follows human behavior accurately with a mean error of 7%. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the predictive value of the Multidimensional Driving Style Inventory (MDSI) for driving behaviour in a driving simulator, in terms of speeding, braking, steering, lateral positioning and maintaining distance to a preceding vehicle. Eighty-eight participants, mainly from the Netherlands and Belgium, filled in the MDSI and drove in a simulator for thirty minutes. Different driving behaviours, including complying with the maximum speed, lateral position and the distance to preceding vehicles, were recorded. The objective data retrieved from the simulator were compared with scores resulting from the questionnaire data. The analysis revealed modest correlations between the self-reported driving styles and the driving behaviour in the driving simulator, similar to those reported in the literature. It is concluded that the current study supports the use of the MDSI as a diagnostic tool for screening participants with different driving styles for simulator studies. [ABSTRACT FROM AUTHOR]

This work deals with the assessment of the actual position of the hands on the steering wheel of drivers of passenger cars in specific driving modes. The findings are compared with the location that is generally considered to be optimal in terms of both active and passive safety, and the long-term effects on the health of the driver. The research described in this work was carried out on a sample of randomly selected drivers in the Czech Republic. For all of the measurements, one identical neutral passenger middle-class vehicle, with which none of the test subjects had previous experience, was selected. The reason for this research was to model a normal situation where the driver controls a vehicle with his hands on the steering wheel in a position that is only the result of his or her own intuition and the subjective sense of the driver's comfort. On the basis, of a statistical evaluation of the obtained data, it was found that the introductory hypothesis, which states that a significant part of the tested sample of drivers holds the steering wheel in an unsuitable manner, can be confirmed. This fact negatively impacts not only on the reduction of active and passive safety, but also affects the health of drivers who drive a large amount of kilometres annually. The results of this work can be used in the design of cabs and modern passenger car systems that will be able to motivate the driver to hold the steering wheel in an optimal way. This will directly affect road safety and positively influence the health of drivers. [ABSTRACT FROM AUTHOR]

Car-following (CF) and lane-changing (LC) behaviours are basic components in driving process. Previous models described them as physical processes with vehicle dynamics and physical criteria. However, drivers’ decisions are greatly influenced by their subjective vision information of various traffic environment elements. To solve this problem, we propose a new concept of traffic environmental vision pressure to explain these two behaviours. The pressure source consists of two parts: nearby vehicles and infrastructures. Pressure models were built to quantify the impact of traffic and roadside infrastructures on these two behaviours. 103 field tests (53 LC and 50 CF) carried out by 40 drivers were conducted to test and calibrate the models. Drivers’ psychological data and vehicle data were collected and postprocessed. Results showed positive relationship between drivers’ psychological stress and vision pressure, which verified the assumption that traffic environmental vision information would have certain effect on driver behaviour. Quantitative thresholds of pressure value were also given and explained with test data. It is concluded that the traffic environmental vision pressure in CF and LC behaviours is quite different, and higher pressure has more impact on behaviour change. We believe that these results will be helpful to study the micro driver behaviour. [ABSTRACT FROM AUTHOR]

This paper proposes a new Lane Keeping Assist (LKA) system based on the integrated control strategy with AFS and BTV. To be specific, the steering controller calculates the gear ratio of AFS to align with the target lane whereas the braking controller determines differential brake pressure using Sliding Mode Control (SMC) theory according to the state-varying sliding surface with Fuzzy model. In recent years, auto industries have produced the lane keeping applications to prevent lane departure caused by drivers’ distractions or drowsiness. To also prevent wrist injury in drivers while steering, current LKA systems limit the output values of steering-wheel assist torque. This limiting mechanism, however, can cause a problem that cannot follow a road curvature when an older driver overexerts an inappropriate control effort. A new LKA system of the AFS and BTV integrated controller has since been drafted to solve this problem, and validated its performance in regards to the test conditions given with various driver models. [ABSTRACT FROM AUTHOR]

Nowadays, more lightweight designs is the key goal of all major automotive industries. One of the main sections for more lightweight automotive area is the Cowl cross bar (CCB) assemblies. A cowl cross bar supports a steering system, airbag module, audio, instrument panel and air conditioning system. The CCB integrates these components into the cockpit module and connects to the body. So the CCB must meet the 5 performance requirements, ① NVH requirement to minimize the vibration, ② Crash performance for less deflection, ③ Steering response requirement for steer predictability, ④ Durability performance like the fatigue life and ⑤ Supporting rigidity for the components. In this study, a new methodology for the optimum CCB design is proposed to obtain a more lightweight design considering 5 targeted requirements. At first, for NVH and Steering response performance, 3-steps of optimization was fulfilled in sequence of (1) Size optimization and mounting position, (2) Case studies about the various types of brackets and (3) Shape optimization using the topology. The proposed design and optimization framework was verified whether it could meet the crash, durability and stiffness requirements. The final optimal CCB would be applied to the new platforms of the Hyundai-Kia motors. [ABSTRACT FROM AUTHOR]

As the market for motor steering components and parts becomes increasingly mature, the requirement for vehicle steering stability becomes strict. Steering wheel torque may fluctuate when the vehicle is running on an uneven road and under steering reversal condition. A change in the return torque of the steering wheel may result in insufficient return or return overshoot, which can affect the vehicle's steering stability. To overcome the adverse effect of random pavement excitation on vehicle return-ability, an electric power steering (EPS) system return control algorithm that integrates disturbance observer and back-stepping sliding-mode algorithm was proposed in this study. First, a return control strategy based on the return torque needed by the vehicle was established. Under the return condition, the observed value of disturbance observer was considered the theoretical basis. Then, the power-assisting motor return current of the EPS system was compensated, and the target current value of return control was determined. A full-vehicle model was established in Adams dynamic simulation software, and a controller model of the EPS system was built in MATLAB software. A random pavement excitation signal was then added in the Adams full-vehicle model, and return-ability was evaluated using vehicle yaw velocity and lateral acceleration. Finally, the stability of the designed system was verified on the test bed. Results show that the return torque provided by the power-assisting motor is verified through a comprehensive performance bench of 2 N.m, and the maximum return residual angle of the steering wheel is kept within 5°, thereby improving the vehicle steering stability. This study provides a theoretical reference for the return response of EPS systems under external excitations of different frequencies. [ABSTRACT FROM AUTHOR]

An integrated chassis control framework that consists of a basic chassis controller and a torque vectoring controller is designed for a three-axle electric bus with distributed motor-driven and active rear steering subsystems. In the basic chassis controller, the active speed limiting control is integrated for antisideslip and antirollover purposes, and the interaxle torque distribution ratio is optimized for energy economy. Meanwhile, the active rear steering control is designed for the tire-wear coordinating purpose. In the torque vectoring controller, the model-based motion control algorithm based on the holistic cornering control method is designed, by which a torque increment is generated at each wheel to change the plane motion states of the vehicle. To solve the optimal torque increment vector, a real-time constrained quadratic programming problem is formulated. The constraints related to the wheel torque limits, the tire friction limits, and the anti-wheel-slip requirements are constructed and converted as the upper and lower bounds of the increments of the longitudinal tire forces. To verify the performance of the control framework, a Trucksim-Simulink cooperative test platform is established. The test results show satisfactory performances on energy economy, anti-wheel-slip, and the safety and stability of the motion control. [ABSTRACT FROM PUBLISHER]

Purpose The purpose of this paper is to present a new optimisation approach for product variance from the purchasing perspective.Design/methodology/approach The research is based on a case study of a collaboration with a global acting automotive Tier 1 supplier, who produces steering systems for cars and commercial vehicles. A total of 116 different variants of three components of a car automotive steering system were analysed and evaluated. The data were gathered from 13 sub-suppliers for three different types of a steering system.Findings Unnecessary time, money, quality and technology can be saved through a greater understanding of such product variances. The results of the case study lead to a general method to optimise existing product variance and present cost improvements and a new key performance indicator to manage product variance out of the purchasing department.Research limitations/implications The research is based on a purchasing case study at a Tier 1 supplier of the automotive branch. The approach can be used for other company departments, e.g. logistics and for different industries than automotive.Practical implications A company can be successful and competitive when it meets the customer needs with a maximum on satisfaction without generating of waste. Unnecessary existing product variance is a kind of waste. The insights of this paper support the operative user and the strategic company management to reduce and improve unnecessary variance in different sections.Originality/value The structured analysis of product variance from the purchasing perspective and the key performance indicator “variance share” are new to company management. The research focuses on the management of existing variance out of the purchasing department which is a segment that has received limited academic attention in research to date. [ABSTRACT FROM AUTHOR]

Much of the Human Factors research into vehicle automation has focused on driver responses to critical scenarios where a crash might occur. However, there is less knowledge about the effects of vehicle automation on drivers’ behaviour during non-critical take-over situations, such as driver-initiated lane-changing or overtaking. The current driving simulator study, conducted as part of the EC-funded AdaptIVe project, addresses this issue. It uses a within-subjects design to compare drivers’ lane-changing behaviour in conventional manual driving, partially automated driving (PAD) and conditionally automated driving (CAD). In PAD, drivers were required to re-take control from an automated driving system in order to overtake a slow moving vehicle, while in CAD, the driver used the indicator lever to initiate a system-performed overtaking manoeuvre. Results showed that while drivers’ acceptance of both the PAD and CAD systems was high, they generally preferred CAD. A comparison of overtaking positions showed that drivers initiated overtaking manoeuvres slightly later in PAD than in manual driving or CAD. In addition, when compared to conventional driving, drivers had higher deviations in lane positioning and speed, along with higher lateral accelerations during lane changes following PAD. These results indicate that even in situations which are not time-critical, drivers’ vehicle control after automation is degraded compared to conventional driving. [ABSTRACT FROM AUTHOR]

This paper deals with global chassis control of automotive vehicles. It focuses on the coordination of suspension and steering/braking vehicle controllers based on the interaction between the vertical and lateral behaviors of the vehicle. It is shown that the lateral acceleration and resulting roll motion of the car generate load transfers that considerably affect vehicle stability. A control law is designed in hierarchical way to improve the overall dynamics of the vehicle and cope with coupled driving maneuvers like obstacle avoidance using steering control and stop-and-go control using braking or driving wheel torque. This global control strategy includes two types of controllers. The first one is the longitudinal/lateral nonlinear flatness controller. Based on an appropriate choice of flat outputs, the flatness proof of a 3 DOF two-wheel nonlinear vehicle model is established. Then, the combined longitudinal and lateral vehicle control is designed using algebraic estimation techniques to provide an accurate estimation of the derivatives and filtering of the reference flat outputs. The second part of the proposed strategy consists of a linear parameter-varying/ [ABSTRACT FROM AUTHOR]

The function of vehicle dynamics control system is adjusting the yaw moment, the longitudinal force and lateral force of a vehicle body through several chassis systems, such as brakes, steering and suspension. Individual systems such as ESC, AFS and 4WD can be used to achieve desired performance by controlling actuator variables. However, integrated chassis control systems that have multiple objectives may not simply achieve the desired performance by controlling the actuators directly. Usually those systems determine the required tire forces in an upper level controller and a lower level controller regulates the tire forces through the actuators. The tire force is controlled in a recursive way based on vehicle state measurement, which may not be sufficient for fast response. For immediate force tracking, we introduce a direct tire force generation method that uses a nonlinear inverse tire model, a pseudo-inverse model of vehicle dynamics and the relationship between longitudinal force and brake pressure. [ABSTRACT FROM AUTHOR]

In this work, the reference model modification strategy for vehicle stability control based on driver's intention recognition under emergent obstacle avoidance situation was proposed. First the conflicts between the driver's emergency alignment (EA) intention and vehicle response characteristics were analyzed in critical emergent obstacle avoidance situation. Second combining steering wheel angle and its speed, the driver's EA intention was recognized. The reference model modification strategy based on steering operation index (SOI) was presented. Then a LQR model following controller with tire cornering stiffness adaption was used to generate direct yaw moment for tracking modified reference yaw rate and reference sideslip angle. Finally based on the four-in-wheel-motor-drive (FIWMD) electric vehicles (EV), double lane change and slalom tests were conducted to compare the results using modified reference model with the results using normal reference model. The experimental tests have proved the effectiveness of the reference model modification strategy based on driver's intention recognition. [ABSTRACT FROM AUTHOR]

Fatigue damage assessment is essential in determining the durability of automobile components. Several studies have been conducted on fatigue durability of steering knuckle using constant amplitude loading. However, most of the engineering structural and components are subjected to Variable Amplitude Loadings (VALs) in service. Therefore, this study aims to present a fatigue damage simulation of automobile steering knuckle of a 1300 cc national automobile using finite element analysis. In this study, the steering knuckle is modeled using computer-aided design software, in which the dimensions are assigned according to 3D scanning files. The critical area on the steering knuckle is determined using commercial finite element software. The strain gauge is then mounted on the steering knuckle and connected to a data acquisition system to capture the actual fatigue strain signal while driving on a residential road. The fatigue strain signal is then used as the VAL in the fatigue damage simulation of automobile steering knuckle. Forged steel, cast aluminum, and cast iron are used and analyzed in the simulation. Results indicate that the different types of material used significantly influenced the fatigue damage of the automobile steering knuckle. [ABSTRACT FROM AUTHOR]