scholarly journals On the Influence of Suspension Geometry on Steering Feedback

2020 ◽  
Vol 10 (12) ◽  
pp. 4297
Author(s):  
Emanuele Bonera ◽  
Marco Gadola ◽  
Daniel Chindamo ◽  
Stefano Morbioli ◽  
Paolo Magri
Keyword(s):  
Driving Simulator ◽  
Front Axle ◽  
Simulation Software ◽  
Steering Wheel ◽  
Active Device ◽  
Driving Experience ◽  
Contact Patch ◽  
Wheel Drive ◽  
Suspension Geometry ◽  
The Impact

Feedback through the steering wheel is known as the most important source of information to the driver. The so-called steering feeling, composed of self-aligning actions coming from tyres and suspension geometry all the way through mechanical linkages to the driver’s hands, provides vital communication for intuitive driving, and it is therefore utterly important for safety and for a pleasant driving experience as well. Subtle forces and vibrations, due to the interaction between the tyre contact patch and the road surface texture, also play a role, provided they are not heavily filtered or cancelled by the power steering system. Human perception is guided by experience in order to establish correlations between steering feedback and vehicle motion in terms of straight-line stability, cornering speed, tyre adhesion and available friction, vehicle balance, and so on. A front-wheel drive car is potentially a critical vehicle from this point of view, especially when the powertrain can deliver large torque figures, and even more so if a limited-slip differential (LSD) or a similar active device is present in order to improve traction capabilities. Any difference between the two wheels in terms of tractive force can result into the so-called torque steer issue, that is to say, a “pulling” sensation on the steering wheel or a shifting of the vehicle from the desired trajectory. This paper analyses the torque steer phenomenon on an all-wheel-drive, full electric sportscar where a significant portion of the torque is transferred to the front axle. The effects of suspension kinematics and the load variation at tyre contact patch level are taken into account. For evaluating the impact of steering feedback, the VI-grade® simulation software is adopted and a test campaign on the professional driving simulator available at the University of Brescia has been carried out in order to understand the impact of steering feedback on driver perception and performance.

Analysis of Vehicle Lateral Response During Regenerative Braking in a Turn

2016 ◽  
Author(s):  
C. S. Nanda Kumar ◽  
Shankar C. Subramanian
Keyword(s):  
Rear Wheel ◽  
Front Wheel ◽  
Lateral Acceleration ◽  
Regenerative Braking ◽  
Steering Wheel ◽  
Slip Angle ◽  
Lateral Response ◽  
Wheel Drive ◽  
Reference Track ◽  
The Impact

Regenerative braking is applied only at the driven wheels in electric and hybrid vehicles. The presence of brake force only at the driven wheels reduces the lateral traction limit of the corresponding tires. This impacts the vehicle lateral response, particularly while applying the regenerative brake in a turn. In this paper, a detailed study was made on the impact of regenerative brake on the vehicle lateral response in front wheel drive and rear wheel drive configurations on dry and wet asphalt road surfaces. Simulations were done considering a typical set of vehicle parameters with the IPG CarMaker® software for different drive conditions and braking configurations along the same reference track. The steering wheel angle, yaw rate, lateral acceleration, vehicle slip angle, and tire forces were obtained. Further, they were compared against the conventional all wheel friction brake configuration. The regenerative braking configuration that had the most impact on vehicle lateral response was analyzed and response variations were quantified.

Function-Specific Uncertainty Communication in Automated Driving

2019 ◽  
Vol 11 (2) ◽  
pp. 75-97
Author(s):  
Alexander Kunze ◽  
Stephen J. Summerskill ◽  
Russell Marshall ◽  
Ashleigh J. Filtness
Keyword(s):  
Augmented Reality ◽  
Situation Awareness ◽  
Driving Simulator ◽  
Automated Driving ◽  
Driving Experience ◽  
Visual Variables ◽  
Simulator Study ◽  
The Impact

Conveying the overall uncertainties of automated driving systems was shown to improve trust calibration and situation awareness, resulting in safer takeovers. However, the impact of presenting the uncertainties of multiple system functions has yet to be investigated. Further, existing research lacks recommendations for visualizing uncertainties in a driving context. The first study outlined in this publication investigated the implications of conveying function-specific uncertainties. The results of the driving simulator study indicate that the effects on takeover performance depends on driving experience, with less experienced drivers benefitting most. Interview responses revealed that workload increments are a major inhibitor of these benefits. Based on these findings, the second study explored the suitability of 11 visual variables for an augmented reality-based uncertainty display. The results show that particularly hue and animation-based variables are appropriate for conveying uncertainty changes. The findings inform the design of all displays that show content varying in urgency.

Function-Specific Uncertainty Communication in Automated Driving

2022 ◽  
pp. 1002-1026
Author(s):  
Alexander Kunze ◽  
Stephen J. Summerskill ◽  
Russell Marshall ◽  
Ashleigh J. Filtness
Keyword(s):  
Augmented Reality ◽  
Situation Awareness ◽  
Driving Simulator ◽  
Automated Driving ◽  
Driving Experience ◽  
Visual Variables ◽  
Simulator Study ◽  
The Impact

Conveying the overall uncertainties of automated driving systems was shown to improve trust calibration and situation awareness, resulting in safer takeovers. However, the impact of presenting the uncertainties of multiple system functions has yet to be investigated. Further, existing research lacks recommendations for visualizing uncertainties in a driving context. The first study outlined in this publication investigated the implications of conveying function-specific uncertainties. The results of the driving simulator study indicate that the effects on takeover performance depends on driving experience, with less experienced drivers benefitting most. Interview responses revealed that workload increments are a major inhibitor of these benefits. Based on these findings, the second study explored the suitability of 11 visual variables for an augmented reality-based uncertainty display. The results show that particularly hue and animation-based variables are appropriate for conveying uncertainty changes. The findings inform the design of all displays that show content varying in urgency.

Left or Right: Auditory Collision Warnings for Driving Assistance Systems

2017 ◽  
Vol 61 (1) ◽  
pp. 1551-1551 ◽  
Author(s):  
Edin Sabic ◽  
Jing Chen
Keyword(s):  
Decision Making ◽  
Driving Simulator ◽  
Steering Wheel ◽  
Warning Systems ◽  
Collision Warning ◽  
Time To Collision ◽  
The Road ◽  
Driving Scenario ◽  
Assistance Systems ◽  
The Impact

Assistance driving systems aim to facilitate human behavior and increase safety on the road. These systems comprise common systems such as forward collision warning systems, lane deviation warning systems, and even park assistance systems. Warning systems can communicate with the driver through various modalities, but auditory warnings have the advantage of not further tasking visual resources that are primarily used for driving. Auditory warnings can also be presented from a certain location within the cab environment to be used by the driver as a cue. Beattie, Baillie, Halvey, and McCall (2014) assessed presenting warnings in stereo configuration, coming from one source, and bilateral configuration, panned fully from left or right, and found that drivers felt more in control with lateral warnings than stereo warnings when the car was in self-driving mode. Straughn, Gray, and Tan (2009) examined laterally presented auditory warnings to signal potential collisions. They found that the ideal presentation of warnings in either the avoidance direction, in which the driver should direct the car to avoid a collision, or the collision direction, in which the potential collision is located, was dependent on time to collision. Wang, Proctor, and Pick (2003) applied the stimulus-response compatibility principle to auditory warning design by using a steering wheel in a non-driving scenario and found that a tone presented monaurally in the avoidance-direction led to the fastest steering response. However, the reverse finding occurred when similar experiments utilized a driving simulator in a driving scenario (Straughn et al., 2009; Wang, Pick, Proctor, & Ye, 2007). The present study further investigated how to design spatially presented auditory collision warnings to facilitate drivers’ response to potential collisions. Specifically, tones indicating a pedestrian walking across the road were presented either in the avoidance direction or in the collision direction. The experimental task consisted of monitoring the road for potential collisions and turning the wheel in the appropriate direction to respond. Additionally, time to collision was manipulated to investigate the impact of the timing of the warning and increasing time pressure on the steering response. Time to collision was manipulated by half second intervals from two to four seconds resulting in five different time-to-collision scenarios. Lastly, the effect of individual differences in decision-making styles were also considered by using two decision-making style questionnaires. Results from the experiment showed that the presentation of a collision warning in the collision direction led to faster responses when compared to the warning in the avoidance direction. This result may be due to the collision warning directing the attention of the participant to the location of the threat so that they can more quickly make a response decision. Further, the advantage of avoidance-direction warnings over collision-direction warnings was greater with greater time to collision. Results showed that participant responses to varying time to collision influenced their reaction time. The participants appeared to have not relied solely on the auditory tones, but rather they utilized the warning tones in conjunction with visual information in the environment. These results from this study have implications for improving collision avoidance systems: Presentation of a collision warning in the direction of the collision may be more intuitive to drivers, regardless of time to collision.

scholarly journals ANALYSIS OF THE IMPACT OF VARIOUS PRESSURES IN THE VEHICLE WHEELS ON THE WHEEL GEOMETRY

2021 ◽  
Vol 1 (50) ◽  
pp. 210-220
Author(s):  
LEW K ◽  
Keyword(s):  
Automatic Device ◽  
Steering System ◽  
Front Axle ◽  
Air Pressure ◽  
Steering Wheel ◽  
The Road ◽  
Significant Difference ◽  
On The Road ◽  
Toe Angle ◽  
The Impact

The steering system in a vehicle is one of the main systems that ensures its controllability and is important for road safety. The steering system consists of two main mechanisms, namely the steering gear, the task of which is to convert the rotary motion into reciprocating motion, and the steering gear, the task of which is to ensure the correct steering of the vehicle. In this case, the steering system is interconnected with the suspension of the car, in which there are four main angles of the wheels that are responsible for the correct maneuverability of the vehicle, namely: camber angle, toe angle, angle of rotation of the axle of the fist and the angle of inclination of the pivot axis of the fist. Measuring the geometry of a vehicle's suspension has several interrelated purposes. One of them is the modification of the stability of the vehicle, that is, the effective impact on the maintenance of the vehicle on the road. Handling also depends on the geometry setting and ensures proper maintenance on the road. Well adjusted geometry ensures even tire wear on each axle. The purpose of the steering system is to maintain the correct position of the steering wheel in relation to the steering wheels. The tests were carried out in stationary conditions at the diagnostic station of the Rzeszow University of Technology using an automatic device for measuring and regulating the air pressure in the tires of the Unitrol PA-10K car and the Launch X-631 car wheel alignment system. The object of the study was a passenger car of the Opel Agila brand. The tests were carried out for various values of air pressure in the car wheels. Based on the above, the task was set - to demonstrate how incorrect air pressure in the wheels of a car changes the angles of inclination of the wheels of the car. When analyzing the obtained test results, it was found that the pressure in the wheels, different from the nominal, but the same in each wheel, does not significantly affect the change in the values of the parameters of the angles of inclination of the vehicle wheels. If the pressure in the wheels on one side of the vehicle drops by 1 bar, there is a significant difference in the camber angles of the front axle. Changes in the air pressure in one of the rear wheels of the car do not significantly affect the angles of inclination of the car wheels. KEY WORDS: AIR PRESSURE IN THE WHEELS, UNEVEN PRESSURE, WHEEL MOUNTING ANGLES, CAMBER AND TOE ANGLES, STEERING.

scholarly journals Drivers’ Braking Behavior Affected by Cognitive Distractions: An Experimental Investigation with a Virtual Car Simulator

2020 ◽  
Vol 10 (10) ◽  
pp. 150
Author(s):  
Nicola Baldo ◽  
Andrea Marini ◽  
Matteo Miani
Keyword(s):  
Driving Simulator ◽  
Cognitive Task ◽  
Phone Call ◽  
Control Group ◽  
Cognitive Resources ◽  
Driving Experience ◽  
Young Drivers ◽  
Significant Difference ◽  
The Moment ◽  
The Impact

In this study, a cohort of 78 university students performed a driving experience in a virtual urban scenario, by means of a car driving simulator, to examine effects of a planned hands-free mobile phone conversation on young drivers’ braking behaviors. To this aim, a control group was left free to drive without any imposed cognitive task. An experimental group faced the same scenario while engaged in a phone call. The conversation via earphones was arranged to diminish the amount of cognitive resources allocated to the driving task. For both groups, the analyses focused on the moment at which a child entered a pedestrian crossing from a sidewalk. The results of a mixed two-way ANOVA showed the presence of a significant difference for distracted and non-distracted drivers with the absence of gender-related differences across the two groups. Distracted participants assumed lower initial speeds, took the first action to stop at shorter distances from the zebra crossing, and had more difficulty in keeping speed variations under control. These findings suggest that the distraction induced by the use of earphones may induce risk compensation behaviors and delay pedestrian perception. Moreover, the effects on the participants’ braking behavior suggest that the procedure adopted to increase cognitive load, based on a story retelling, is an effective method to analyze the impact of hands-free cellphone use on driving skills in a car simulation experiment.

scholarly journals IMPACT OF THE INFLATION PRESSURE OF THE TIRES ON LEAD OF FRONT DRIVE WHEELS AND MOVEMENT RESISTANCE FORCE OF TRACTORS

Transport ◽  
2019 ◽  
Vol 34 (6) ◽  
pp. 628-638
Author(s):  
Algirdas Janulevičius ◽  
Povilas Gurevičius
Keyword(s):  
Rear Axle ◽  
Front Wheel ◽  
Front Axle ◽  
Resistance Force ◽  
Inflation Pressure ◽  
Wheel Drive ◽  
Braking Torque ◽  
Drive Axle ◽  
The Impact ◽  
Additional Losses

The transmission of mechanical front-wheel drive tractors normally has a front axle lead ratio, which is equal to 1.5…2.5%. Naturally, when ballast masses are added to the tractor or when inflation pressure in the tires is reduced, distortion of the tires is inevitable, which changes the lead of the front wheels. In this paper, we present the impact of tire inflation pressures on the lead front drive wheels and movement resistance force when the tractor travelled with a front drive axle enabled and was engine braking with the fuel supply off. It was found that the variation in front and rear tires inflation pressure combination can significantly change the lead of the front drive wheels. For the tested tractor up to 6.9%. The result is that when the tractor travelled with the front axle enabled and was engine braking, the engine-braking efficiency decreases with increasing lead of the front wheels. Front (slipping) wheels create the opposite-direction torque, which is transferred to the rear wheels through the tractor’s front-rear axle drive system. Additional losses of the engine braking occur in transmission due to power circulation, and the result is that the tractor wheels receive less braking torque from the engine.

scholarly journals Computer Simulation of Car Aerodynamic Properties

2017 ◽  
Vol 65 (5) ◽  
pp. 1505-1514 ◽  
Author(s):  
Ivan Janoško ◽  
Tomáš Polonec ◽  
Peter Kuchar ◽  
Pavel Máchal ◽  
Martin Zach
Keyword(s):  
Rear Axle ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Front Axle ◽  
Simulation Software ◽  
The Body ◽  
Body Parts ◽  
Aerodynamic Properties ◽  
Before And After ◽  
The Impact

The paper presents an optimization of car aerodynamic properties using the simulation software STAR‑CCM+. For real simulation was used tested car Fiat 127 which was modified on the performance car. The basic objective of this work is using computer simulations to obtain knowledge about the impact of individual body parts on the results of aerodynamic drag, downforce or lift. Based on the results, bodywork modifications will be designed to improve the aerodynamic characteristics of the body, but would not disrupt the basic shape and appearance of the vehicle. The modifications will be again subjected to tests in simulation software. On the modified body was significantly reduced torque of the front axle, while increased of rear axle (cca 1250 N.m). This caused a significant stabilizing effect on the rear axle. The results of simulation tests before and after use bodywork modifications are processed in graphical and numerical form.

scholarly journals Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2690
Author(s):  
Bo Pan ◽  
Xuguang Wang ◽  
Zhenyang Xu ◽  
Lianjun Guo ◽  
Xuesong Wang
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Joint Angle ◽  
Simulation Software ◽  
Dissipated Energy ◽  
Energy Structure ◽  
Joint Angles ◽  
Crack Penetration ◽  
Before And After ◽  
The Impact

The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.

A simplified iterative approach for testing the pulse derailment of light rail vehicles across a viaduct to near-fault earthquake scenarios

2021 ◽  
pp. 095440972098741
Author(s):  
Ling-Kun Chen ◽  
Peng Liu ◽  
Li-Ming Zhu ◽  
Jing-Bo Ding ◽  
Yu-Lin Feng ◽  
...  
Keyword(s):  
Ground Motions ◽  
Simulation Software ◽  
Light Rail ◽  
Rail Transit ◽  
Light Rail Transit ◽  
Seismic Responses ◽  
Near Fault ◽  
Rail Vehicle ◽  
Pulse Type ◽  
The Impact

Near-fault (NF) earthquakes cause severe bridge damage, particularly urban bridges subjected to light rail transit (LRT), which could affect the safety of the light rail transit vehicle (“light rail vehicle” or “LRV” for short). Now when a variety of studies on the fault fracture effect on the working protection of LRVs are available for the study of cars subjected to far-reaching soil motion (FFGMs), further examination is appropriate. For the first time, this paper introduced the LRV derailment mechanism caused by pulse-type near-fault ground motions (NFGMs), suggesting the concept of pulse derailment. The effects of near-fault ground motions (NFGMs) are included in an available numerical process developed for the LRV analysis of the VBI system. A simplified iterative algorithm is proposed to assess the stability and nonlinear seismic response of an LRV-reinforced concrete (RC) viaduct (LRVBRCV) system to a long-period NFGMs using the dynamic substructure method (DSM). Furthermore, a computer simulation software was developed to compute the nonlinear seismic responses of the VBI system to pulse-type NFGMs, non-pulse-type NFGMs, and FFGMs named Dynamic Interaction Analysis for Light-Rail-Vehicle Bridge System (DIALRVBS). The nonlinear bridge seismic reaction determines the impact of pulses on lateral peak earth acceleration (Ap) and lateral peak land (Vp) ratios. The analysis results quantify the effects of pulse-type NFGMs seismic responses on the LRV operations' safety. In contrast with the pulse-type non-pulse NFGMs and FFGMs, this article's research shows that pulse-type NFGM derail trains primarily via the transverse velocity pulse effect. Hence, this study's results and the proposed method can improve the LRT bridges' seismic designs.

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