In the automotive industry, improving vehicle operability tailored to individual drivers is essential for achieving a long and enjoyable driving experience. This study presents a demonstration of a personal-fit control system that adaptively adjusts vehicle characteristics to match each driver’s preferred operability. The experiment is conducted using a driving simulator. In addition, an evaluation method based on a Kalman filter is examined. The results indicate that optimal vehicle characteristics vary among drivers, and that the personal-fit control system enables adaptation to these individual preferences.

Projection mapping (PM) is useful in the product design process, since it seamlessly bridges a physical mockup and its digital twin by allowing designers to interactively explore new textures, colors, and shapes without the need to create new physical mockups. While PM has proven effective for car interior design, previous research focused solely on supporting the design of dashboards and instrument panels, neglecting evaluation in realistic driving scenarios. This paper introduces a self-contained car interior design support system that extends beyond the dashboard to include the A-pillars. Additionally, to enable designers to evaluate their designs in authentic driving conditions, we integrate a driving simulator, complete with a motion platform, into the PM system. Through the construction of a prototype, we demonstrate the feasibility of our proposed system. Finally, through user studies, we derive guidelines for PM-based car interior design to optimize the user experience.

With the recent diversification of operating devices, the demand for input operations that require confirmation of the effect of differences in display response on operability has increased. Regarding display response, previous studies have investigated the threshold time and sense of agency for a delayed response during device operation. However, these studies only focused on subjective evaluations. Therefore, this study aims to clarify the human motor characteristics and activated brain regions based on the differences in display response time during device operation. The target motion is the rotational operation of the cylindrical rotary controller using the index finger and thumb. The experimental conditions involve four types of display response times (the duration from the operation to the indicated response). We measured the brain activity using near-infrared spectroscopy, the muscle activity from a surface myoelectric potential measurement device, and the force data of the index finger and thumb tip obtained from two independent six-axis force/torque sensors. Although the experimental results showed no significant difference in the muscle activity and gripping force, a significant difference was observed in the brain activity and the questionnaire survey by the difference in display response time. This investigation reveals that the difference in display response time affects brain activity and subjective information, clarifying the relationship between brain activity and subjective information.

This study aim to confirm the effect of viscosity characteristics differences on the rotational manipulation of a cylindrical rotary controller with the index finger and thumb through a quantitative analysis and evaluation of muscle and brain activations. The target motion was a rotary manipulation with the index finger and thumb of a cylindrical rotary controller with a 50 mm diameter. The rotary motion of the controller produces a click sensation at every 12 degrees in the rotation. The experimental conditions were three conditions with different viscosity characteristics related to the rotary motion of the controller. The subjects were six right-handed healthy males with a mean age of 21.7 (S. D.: 1.03) years. We analyzed the brain activity from a near- infrared spectroscopy measurement system, the muscles activity using a surface myoelectric potential measurement device, the force data at the index finger and thumb tip using two independent six-axis force/torque sensors, and the position data using a 3D position measurement device. The experimental results showed that there was no significant difference in the questionnaire survey, muscle activity, and grasping force, respectively; however, a significant difference in brain activity was observed with increased controller viscosity. Therefore, it became clear that there was a change in the brain activity when rotating the cylindrical rotary controller with the viscosity characteristics related to the rotary motion.

Car interior design, such as dashboard, broadly consists of two parts. One is shape design, where the processes of 2D drawing, 3D modeling and evaluation with full-scale mockups are iterated, which takes a massive amount of time and cost. The other is material design such as surface property tuning, where designers compare material samples. This way, however, has a limitation on the number of material samples to compare and does not allow applying of the samples of interest to the whole mockups in early phases. In this paper, we apply projection mapping technique to boost the design process by altering the appearance of the surface of projected objects and enabling various shape and material evaluations in early phases. Our proposed system uses multiple projectors, one of which is 4K projector to reproduce fine leather surface. Utilizing physiological and psychological depth cues, the system allows the user to perceive the projected mockup as deformed. Psychological experiments confirm that users perceive deformation and have controlled impression on leather reproduced with certain parameters. In addition, we discuss the usability of the proposed system as a support system of car interior design.

A human can control dynamic properties of his/her own body naturally and effectively according to tasks by utilizing the perceived information of environmental characteristics. If dynamic properties of human movements depending on environmental characteristics can be described quantitatively, there would be expected to design and develop a novel human-machine system in which an operator can manipulate more comfortably. This paper discusses a design methodology of human-machine systems integrating human motor characteristics. A vehicle interface system manipulated by the foot is focused on, and mechanical impedance properties of human lower extremities during maintained leg posture are investigated according to the leg posture and the foot force