Toward a Comfortable Driving Experience for a Self-Driving Shuttle Bus

The convergence of mechanical, electrical, and advanced ICT technologies, driven by artificial intelligence and 5G vehicle-to-everything (5G-V2X) connectivity, will help to develop high-performance autonomous driving vehicles and services that are usable and convenient for self-driving passengers. Despite widespread research on self-driving, user acceptance remains an essential part of successful market penetration this forms the motivation behind studies on human factors associated with autonomous shuttle services. We address this by providing a comfortable driving experience while not compromising safety. We focus on the accelerations and jerks of vehicles to reduce the risk of motion sickness and to improve the driving experience for passengers. Furthermore, this study proposes a time-optimal velocity planning method for guaranteeing comfort criteria when an explicit reference path is given. The overall controller and planning method were verified using real-time, software-in-the-loop (SIL) environments for a real-time vehicle dynamics simulation the performance was then compared with a typical planning approach. The proposed optimized planning shows a relatively better performance and enables a comfortable passenger experience in a self-driving shuttle bus according to the recommended criteria. Document type: Articl

An Inverse Vehicle Model for a Neural-Network-Based Integrated Lateral and Longitudinal Automatic Parking Controller

The majority of currently used automatic parking systems exploit the planning-and-tracking approach that involves planning the reference trajectory first and then tracking the desired reference trajectory. However, the response delay of longitudinal velocity prevents the parking controller from tracing the desired trajectory because the vehicle’s velocity and other state parameters are not synchronized, while the controller maneuvers the vehicle according to the planned desired velocity and steering profiles. We propose an inverse vehicle model to provide a neural-network-based integrated lateral and longitudinal automatic parking controller. We approximated the relationship of the planned velocity to the vehicle’s velocity using a second-order difference equation that involves the response characteristic of the vehicle’s longitudinal delay. The adjusted desired velocity to track the origin-planned velocity is calculated using the inverse vehicle model. Furthermore, we proposed an integrated longitudinal and lateral parking controller using an artificial neural network (ANN) model trained on a dataset applying the inverse vehicle model. By learning the control laws between the vehicle’s states and the corresponding actions, the proposed ANN-based controller could yield a steering angle and the adjusted desired velocity to complete automatic parking in a confined space

Adaptive Integrated Thermal Management System for a Stable Driving Environment in Battery Electric Vehicles

With an increase in global warming, battery electric vehicles (BEVs), which are environmentally friendly, have been rapidly commercialized to replace conventional vehicles with internal combustion engines. Unlike traditional internal combustion engine vehicles, the powertrain system of BEVs operates with high efficiency, resulting in lower heat generation. This poses a challenge for cabin heating under low-temperature conditions. Conversely, under high-temperature conditions, the operating temperature of a high-voltage battery (HVB) is lower than the ambient air temperature, which makes cooling through ambient air challenging. To overcome these challenges, in this study, we proposed an integrated thermal management system (ITMS) based on a heat pump system capable of stable thermal management under diverse climatic conditions. Furthermore, to assess the ability of the proposed ITMS to perform thermal management under various climatic conditions, we integrated a detailed powertrain system model incorporating BEV specifications and the proposed ITMS model based on the heat pump system. The ITMS model was evaluated under high-load-driving conditions, specifically the HWFET scenario, demonstrating its capability to perform stable thermal management not only under high-temperature conditions, such as at 36 °C, but also under low-temperature conditions, such as at −10 °C, through the designated thermal management modes

A High Speed CMOS Image Sensor with a Novel Digital Correlated Double Sampling and a Differential Difference Amplifier

In order to increase the operating speed of a CMOS image sensor (CIS), a new technique of digital correlated double sampling (CDS) is described. In general, the fixed pattern noise (FPN) of a CIS has been reduced with the subtraction algorithm between the reset signal and pixel signal. This is because a single-slope analog-to-digital converter (ADC) has been normally adopted in the conventional digital CDS with the reset ramp and signal ramp. Thus, the operating speed of a digital CDS is much slower than that of an analog CDS. In order to improve the operating speed, we propose a novel digital CDS based on a differential difference amplifier (DDA) that compares the reset signal and the pixel signal using only one ramp. The prototype CIS has been fabricated with 0.13 µm CIS technology and it has the VGA resolution of 640 × 480. The measured conversion time is 16 µs, and a high frame rate of 131 fps is achieved at the VGA resolution

Comprehensive Evaluation of the Visual Environment of a Railroad Station’s Platform, Focused on the User’s Psychology

Through a comprehensive evaluation of the spaces of 25 railway stations, where power-saving operations are being conducted due to an earthquake, the effects of various components of the space on users’ psychology were reviewed. For the platforms of railway stations, which are divided into ‘island platforms’ and ‘side platforms’ the ‘physical quantity measurement’ and ‘impression evaluation’ were assessed. When a simple power-saving method, such as partial lighting up is adopted, it has been shown that there is a negative effect on the users, both physically and psychologically. In particular, in the case of outdoor platforms, there is a concern that glare and anxiety due to contrast may increase; therefore, it is necessary to utilize the reflective surfaces effectively. Floor illuminance is fundamental to lighting design. However, some areas cannot be evaluated by floor illuminance alone. The difference in the results of the impression evaluation in five areas with floor illuminance around 50 lx was widely distributed, and it was found that the shape and material of the space affected the results. If platform screen doors are installed, a lighting method that can evenly illuminate the interior of the space is necessary. By reviewing each factor that determines the visual impression, it was revealed that the lighting location and lighting method were significantly affected

Investigation of the Visual Environment of Railway Station Stairs Using Qualitative and Quantitative Evaluation Methods

A qualitative evaluation was performed by comprehensively considering the lighting environment of each staircase of 20 railway stations in Tokyo, the width of the stairs, the type of ceiling, wall lighting fixtures, and the color. As a result of the quantitative evaluation of 20 stairs, it was found that a difference of up to 400 lx occurred in the measurement results of the entrance, exit, and middle landing, even for the same stairs. As a result of qualitative evaluation, it was found that the quantitative evaluation result and the simple proportional relationship were not established. It was found that simply physically brightening a space cannot make a comfortable and safe space, and in some cases, glare is likely to occur. As a result of the analysis of variance and correlation analysis, it was found that the characteristics of the space, especially the material of the wall and the location of the lighting equipment, had a large effect on the impression of the space. As a result of simulation analysis, it was found that the performance varied greatly depending on the installation location of the lighting. In particular, the method of installing the line light source close to the ground was effective. In designing stair lighting for public facilities in the future, it is considered that qualitative factors such as the finishing of walls and ceilings, installation positions, and angles of lighting fixtures, which are environmental components other than lighting, should also be considered