Haptic device for virtual prototyping

In determining the quality of a car, switch feeling is one of the important factors. Designing switches is time consuming because the relationships between characteristics of a desired switch and design parameters such as spring stiffness or stroke are not very clear, and furthermore, physical evaluation requires prototypes. A haptic Virtual Prototyping Environment (VPE), in which CAE (Computer-Aided Engineering) and haptic interface work together to display virtual feelings of mechanisms designed by CAD (Computer-Aided Design) will enable designers to feel the motions of the designed switches without prototypes. This paper presents design and quantitative evaluation of a haptic VPE for power window switches. We compared relationship between displacement and static reaction force, and acceleration during clicking motion. The similarity in the force vs stroke curve (FS curve) suggests the overall similarity in the feeling of the whole switch stroke. The acceleration showed some differences, which was felt as somewhat softer clicking effect. The lower frequency of the residual vibration of the haptic device indicates that the equivalent inertia of the haptic device is larger than that of the real switch. Although the overall motion of the switch stroke felt similar, quality of reality needs further refinement. Introduction of acceleration feedback for reducing the equivalent inertia is discussed.