Atsuhide Kishi

A Subjective Force Perception Model of Humans and Its Application to a Steering Operation System of a Vehicle

The present study clarifies the human characteristics of motion and perception, and develops a force perception model in vehicle operation. As the first step, this paper analyzes experimentally human force perception properties during steering operation, in which multiple joint motions and large postural changes of arms are necessary. The experimental results reveal the following three points: a) force perception follows the Weber-Fechner law under the constant arm posture, b) force perception changes depending on the steering wheel angle and is affected by arm weight and force perception properties, and c) the same tendency of force perception properties is observed even if the steering direction changes. Finally, a force perception model in sending a steering wheel is proposed.

Investigation of the subjective force perception based on the estimation of the muscle activities during a steering operation

The models of motion and perception characteristics of humans are helpful to evaluate subjective efforts associated with intuitive, safe, and easy-to-use products. Traditionally, the muscle activity and/or the joint torque estimated by using a musculoskeletal model have been evaluated, whereas there are few studies that consider humans perception characteristics. In this paper, the perception characteristics of force are investigated based on the estimation of the muscle activities. Experimental analysis of human force perception characteristics in a steering wheel operation has revealed that the perceived force depends on the angle of the steering wheel and the direction of the load. This paper proposes the estimation model of the force perceived by a subject that considers humans posture- and direction-dependent perception characteristics in the steering operation. We estimate the muscle activity during the steering wheel operation by using a three-dimensional musculoskeletal model, develops a perception conversion model that follows the Weber-Fechner law, and describes the experimental results that confirm the feasibility of the proposed force perception estimation.

Windshield Frame Shape and Awareness of the External World While Driving an Automobile

The vehicle windshield is supported and framed by the hood, roof, and pillars, which occlude the driver’s view of the outside. It has been previously shown that awareness of the external world changes according to differences in windshield shape. This directly affects the drivability of a vehicle. Thus, the windshield shape must be designed by considering driver’s visual performance so that it can be balanced with other performance measures such as weight and roominess to design the optimal cockpit. Visual performance during driving is affected by (1) bottom-up attention and (2) top-down attention, and (3) selection between them. This study focuses on Itti and Koch’s visual saliency that attracts bottom-up attention as a visual scene changes in shape and color around front windshield frame during driving. This paper aims to quantify the relationships between drivers’ gaze movements and visual saliency.