An extended model of the ISO-2631 standard to objectify the ride comfort in autonomous driving

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S37-S45
Author(s):  
Georg Burkhard ◽  
Tobias Berger ◽  
Erik Enders ◽  
Dieter Schramm
Keyword(s):  
Ride Comfort ◽  
Autonomous Driving ◽  
Extended Model ◽  
Measuring Point ◽  
Significant Difference ◽  
Comfort Perception ◽  
Simulator Study ◽  
Iso 2631

BACKGROUND: With the development of autonomous driving, the occupants’ comfort perception and their activities during the drive are becoming increasingly the focus of research. Especially in one of the first applications, a drive on a motorway, vertical dynamics play a major role. OBJECTIVE: To be able to robustly objectify ride comfort, better models need to be developed. Initial studies have shown, that the current ISO-2631 standard creates good results in the objectification and can be regarded as benchmark. METHODS: To increase the accuracy in objectification, an extended model with the occupants’ head as additional measuring point is introduced. Instead of the known frequency filters, weighting (k-factors) is used to differentiate possible excitations. For comparing the model with the ISO-2631, a simulator study with 5 excitations and 50 inattentive subjects is carried out. RESULTS: Evaluating the study with the ISO-2631, 3 out of 5 excitations indicate a significant difference between the occupant’s impression and the calculated comfort value. In comparison the extended model has no significant difference. CONCLUSION: The results further show, that inattentive occupants move their heads significantly more. By measuring accelerations of the head, the extended model creates equivalent or more accurate comfort values than the ISO-2631.

scholarly journals Passengers Comfort Perception and Demands on Railway Vehicles: A Review

2020 ◽  
Author(s):  
Patrícia Filipa Pinheiro da Silva ◽  
Joaquim Mendes
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Railway Transportation ◽  
Railway Vehicles ◽  
Comfort Perception ◽  
High Speed Trains ◽  
Ride Comfort Evaluation ◽  
Iso 2631 ◽  
Temperature Noise

Trains are becoming a popular way of transportation driven by comfort and ecology reasons. Latest statistics showed an increasing of 40% on the number of passengers in the last decade. The development of new high-speed trains promoted an evolution on the coaches interiors, as to make railway transportation more attractive. To cope this objective, new requirements were set, namely high levels of comfort and safety. In complement, multiple long-term ride comfort evaluation methods have been developed. The aim of this work is to present a review on the passengers’ comfort perception    in railway vehicles. The standards ISO 2631, EN 12299 and the Sperling’s method are the most used ones. They refer several factors, as the vibration (level, frequency and duration), temperature, noise and area of the train per capita. Additionally, the perception of reduced accidents delayed the studies of passive security. Therefore, recent works focus on reducing the consequences of the second impact in case of accident and minimize the biomechanics injury criterion, through new interiors design layouts. Keywords: Railway vehicles, Passengers comfort, Posture, Ride evaluation, Passive safety

scholarly journals Sequential Coordination between Lingual and Pharyngeal Pressures Produced during Dry Swallowing

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jitsuro Yano ◽  
Yoichiro Aoyagi ◽  
Takahiro Ono ◽  
Kazuhiro Hori ◽  
Wakami Yamaguchi ◽  
...  
Keyword(s):  
Strong Correlation ◽  
Healthy Subjects ◽  
Hard Palate ◽  
Flow Dynamics ◽  
Tongue Pressure ◽  
Pressure Flow ◽  
Measuring Point ◽  
Pharyngeal Pressure ◽  
Median Part ◽  
Significant Difference

The aim of this study was to investigate oropharyngeal pressure flow dynamics during dry swallowing in ten healthy subjects. Tongue pressure (TP) was measured using a sensor sheet system with five measuring points on the hard palate, and pharyngeal pressure (PP) was measured using a manometric catheter with four measuring points. The order and correlations of sequential events, such as onset, peak, and offset times of pressure production, at each pressure measuring point were analyzed on the synchronized waveforms. Onset of TP was earlier than that of PP. The peak of TP did not show significant differences with the onset of PP, and it was earlier than that of PP. There was no significant difference between the offset of TP and PP. The onset of PP was temporally time-locked to the peak of TP, and there was an especially strong correlation between the onset of PP and TP at the posterior-median part on the hard palate. The offset of PP was temporally time-locked to that of TP. These results could be interpreted as providing an explanation for the generation of oropharyngeal pressure flow to ensure efficient bolus transport and safe swallowing.

scholarly journals Driver Take-Over Reaction in Autonomous Vehicles with Rotatable Seats

Safety ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 34
Author(s):  
Shi Cao ◽  
Pinyan Tang ◽  
Xu Sun
Keyword(s):  
Reaction Time ◽  
Interior Design ◽  
Situation Awareness ◽  
Repeated Measures ◽  
Autonomous Vehicles ◽  
Driving Simulator ◽  
Autonomous Driving ◽  
Maximum Magnitude ◽  
Significant Difference ◽  
Driving Conditions

A new concept in the interior design of autonomous vehicles is rotatable or swivelling seats that allow people sitting in the front row to rotate their seats and face backwards. In the current study, we used a take-over request task conducted in a fixed-based driving simulator to compare two conditions, driver front-facing and rear-facing. Thirty-six adult drivers participated in the experiment using a within-subject design with take-over time budget varied. Take-over reaction time, remaining action time, crash, situation awareness and trust in automation were measured. Repeated measures ANOVA and Generalized Linear Mixed Model were conducted to analyze the results. The results showed that the rear-facing configuration led to longer take-over reaction time (on average 1.56 s longer than front-facing, p < 0.001), but it caused drivers to intervene faster after they turned back their seat in comparison to the traditional front-facing configuration. Situation awareness in both front-facing and rear-facing autonomous driving conditions were significantly lower (p < 0.001) than the manual driving condition, but there was no significant difference between the two autonomous driving conditions (p = 1.000). There was no significant difference of automation trust between front-facing and rear-facing conditions (p = 0.166). The current study showed that in a fixed-based simulator representing a conditionally autonomous car, when using the rear-facing driver seat configuration (where participants rotated the seat by themselves), participants had longer take-over reaction time overall due to physical turning, but they intervened faster after they turned back their seat for take-over response in comparison to the traditional front-facing seat configuration. This behavioral change might be at the cost of reduced take-over response quality. Crash rate was not significantly different in the current laboratory study (overall the average rate of crash was 11%). A limitation of the current study is that the driving simulator does not support other measures of take-over request (TOR) quality such as minimal time to collision and maximum magnitude of acceleration. Based on the current study, future studies are needed to further examine the effect of rotatable seat configurations with more detailed analysis of both TOR speed and quality measures as well as in real world driving conditions for better understanding of their safety implications.

scholarly journals Train-Bridge Dynamic Behaviour of Long-Span Asymmetrical-Stiffness Cable-Stayed Bridge

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yuexing Wu ◽  
Jianting Zhou ◽  
Jinquan Zhang ◽  
Qiang Wen ◽  
Xuan Li
Keyword(s):  
Dynamic Behaviour ◽  
Model Updating ◽  
Ride Comfort ◽  
Observation Point ◽  
Main Beam ◽  
Train Track ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Significant Difference ◽  
Track Bridge

Long-span cable-stayed bridge (LCB) with unequal-height towers is being designed and constructed in metro lines due to its better adaptability to environment and terrain conditions compared to traditional cable-stayed bridge with equal-height towers. However, the asymmetrical arrangement of towers leads to obvious nonuniformity of the structural stiffness along the longitudinal direction, which intensifies the wheel-rail coupled vibration behaviour, and affects the running safety of operating trains and ride comfort. Therefore, train-bridge dynamic behaviour of long-span asymmetrical-stiffness cable-stayed bridge is deeply investigated in this work. Primarily, considering the comprehensive index of frequency difference and modal assurance criterion (MAC), a nonlinear model updating technique (NMUT) based on penalty function theory is proposed, which can be used to optimize the bridge numerical model. Secondly, on the basis of the train-track-bridge dynamic interaction theory (TDIT), a train-track-bridge coupled dynamic model (TCDM) is established. Finally, a LCB with unequal-height towers is applied as a case to illustrate the influence of asymmetrical stiffness on the train-track-bridge dynamic characteristics. Results show that the proposed NMUT is efficacious and practical. For the LCB with unequal-height towers, a significant difference between the bridge vibration at low tower location and that at high tower location appears. The vertical displacement difference of the main beam on both sides of the bridge increases with the distance from the observation point to the bridge tower increasing. The variation of acceleration difference on both sides of the bridge is influenced by the speed of the train and the position of the observation point simultaneously. In general, vibrations of the main beam at low tower location are larger than those at high tower location.

Evaluation of Passenger Ride Comfort of Indian Rail and Road Vehicles with ISO 2631-1 Standards Part 2 - Simulation

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
R.C. Sharma
Keyword(s):  
Ride Comfort ◽  
Road Vehicles ◽  
Rail Vehicle ◽  
Normal Duration ◽  
Indian Railway ◽  
Iso 2631 ◽  
Comfortable Ride

In this paper ride comfort of Indian road and rail vehicle is evaluated using ISO 2631-1 comfort specifications. A three wheel vehicle, light four wheel vehicle and general sleeper ICF coach of Indian railway have been evaluated on the basis of 1 hr, 2.5 hrs, 4 hrs and 8 hrs ISO 2631 comfort specifications in seated position as these are the normal duration for passengers. An insight to comfortable ride duration for these vehicles is presented in this paper.

Evaluation of Passenger Ride Comfort of Indian Rail and Road Vehicles with ISO 2631-1 Standards Part 1 - Mathematical Modelling

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
R.C. Sharma
Keyword(s):  
Mathematical Modelling ◽  
Ride Comfort ◽  
Dominant Factor ◽  
Ride Quality ◽  
Passenger Vehicle ◽  
Performance Indices ◽  
Road Vehicles ◽  
Rail Vehicles ◽  
Indian Railway ◽  
Iso 2631

Ride quality and ride comfort are the most important performance indices of road or rail vehicles and is affected by various factors, such as vibrations, acoustics, smell, temperature, visual stimuli, humidity and seat design. Among these vibration is a dominant factor that influences the performance indices the most. In this work the coupled vertical-lateral mathematical models of Indian rail and road vehicles have been formulated using Lagrangian. The roadway vehicles considered for this analysis are three wheel and light four wheel Indian passenger vehicle. The rail vehicles considered for this analysis are General sleeper ICF coach of Indian railway.

Analysis of bio-dynamic model of seated human subject and optimization of the passenger ride comfort for three-wheel vehicle using random search technique

2021 ◽  
Vol 235 (1) ◽  
pp. 106-121
Author(s):  
Rakesh Chandmal Sharma ◽  
Sakshi Sharma ◽  
Sunil Kumar Sharma ◽  
Neeraj Sharma ◽  
Gurpreet Singh
Keyword(s):  
Dynamic Model ◽  
Human Subject ◽  
Present Model ◽  
Ride Comfort ◽  
Random Search ◽  
Linear Optimization ◽  
Search Technique ◽  
Random Surface ◽  
Surface Irregularities ◽  
Iso 2631

Ride comfort is the major concern to the roadway vehicle passengers, travelling in as it affects their health and efficiency to work. In the present study, a 9 DoF model of a three-wheel vehicle is developed with Lagrangian approach to investigate its ride behavior when subjected to random surface irregularities. The irregularities of the track are measured with a three-wheeled setup equipped with profilometer known as opto-coupler. The present model is validated in two ways, first by comparing the vertical-lateral PSD acceleration received from simulation and actual testing and second by comparing vertical seat to head transmissibility obtained from analysis (VSTH) with past reported studies. A 7 DoF bio-dynamic model of the seated human subject is formulated and integrated with the vehicle model, ride comfort of the vehicle and human body segments are assessed based on ISO specifications. Passenger Ride Comfort is optimized through non-linear optimization using Random Search Technique. The modified values of vehicle suspension parameters are presented to obtain optimum passenger comfort based on ISO-2631-1 criteria.

Optimum design for passive suspension system of a vehicle to prevent rollover and improve ride comfort under random road excitations

2016 ◽  
Vol 230 (4) ◽  
pp. 426-441 ◽  
Author(s):  
Abolfazl Seifi ◽  
Reza Hassannejad ◽  
Mohammad A Hamed
Keyword(s):  
Frequency Domain ◽  
Ride Comfort ◽  
Suspension System ◽  
Vertical Acceleration ◽  
Optimized Design ◽  
Power Spectral ◽  
Road Roughness ◽  
Vehicle Suspension System ◽  
Iso 2631

The main functions of suspension system are to provide ride comfort for the passengers and vehicle handling (road holding). But, in many studies, full attention to the ride comfort leads to the determination of incorrect suspension system parameters as well as other problems such as rollover and reducing road-holding ability in the vehicle. The aim of this study is to present a method for the optimized design of the vehicle suspension system in order to improve the ride comfort, road holding, workspace and preventing rollover, considering a full vehicle model with 11-DOF. The most important feature of this study is that the prevention of rollover factor and all of suspension functions are considered simultaneously. In this research, in order to assess the ride comfort, the vertical acceleration values of seats that are caused by random road roughness are calculated by power spectral density of road in frequency domain. In the context of prevention of rollover, Fishhook manoeuvre is performed using a mathematical model for the roll motion, and then the dynamic behaviour of the variables is considered in rollover threshold. Then, the optimization problem is solved to minimize the vertical acceleration values and vehicle roll angle by considering the physical limitation and safety of the model. The results of the optimization show that the vertical acceleration, in frequency domain at the desired boundary values (as defined in ISO 2631), decreases and rollover resistance of the vehicle increases.

Comparing Audio and Tactile Inputs as Driver Attention Control

2002 ◽  
Vol 46 (21) ◽  
pp. 1777-1781
Author(s):  
Lisbeth Almén
Keyword(s):  
Secondary Task ◽  
Focus Of Attention ◽  
Attention Control ◽  
Main Task ◽  
Tactile Sense ◽  
Car Accidents ◽  
Significant Difference ◽  
Driving Task ◽  
Simulator Study ◽  
Own Name

In this simulator study we compared the effects that two different alerting devices had on driver attention control. The alerting devices were presented to the audio and tactile sense modality respectively. The audio alerting was in form of the driver's own name and the tactile device was in form of vibrations similar to those produced by rumble lines. While driving, the driver was distracted by a secondary task. The alerting device was then used to make the driver change his/her focus of attention back to the main task of driving. No significant difference between the alerting devices was found. A combination of the two alerting devices shows a tendency to provide the most rapid switch of attention back to focus on the main driving task. This paper is part of a study to discriminate an efficient way to alert a distracted driver so that car accidents may be reduced.

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