Doctor of Philosophy

dissertationVirtual reality is becoming a common technology with applications in fields such as medical training, product development, and entertainment. Providing haptic (sense of touch) information along with visual and audio information can create an immersive virtual environment and enables intuitive interaction with objects in the environment. Haptic information is usually categorized into two modalities: kinesthetic (force) feedback and tactile (cutaneous) feedback. Compared to kinesthetic-force feedback, tactile feedback conveys high-resolution and low-level force information, which enables precise discrimination and dexterous manipulation of small or delicate objects. The main drawback of the state-of-the-art tactile display devices is the lack of transparency and mobility since replicating a realistic tactile sensation on a fingerpad requires a high degree of freedom system. This dissertation presents the development of two separate haptic interfaces in which simplified tactile feedback for local contact geometry and compliance information are displayed on a user's fingerpad via a compact tactile display device. The first interface is a two-degree-of-freedom contact location display device, which improved upon the capabilities of prior one-degree-of-freedom contact location display device designs. This device renders the location of contact between the user's fingerpad and three-dimensional virtual objects. The results of a virtual ball manipulation experiment showed that providing two-degree-of-freedom contact location information, in addition to kinesthetic force feedback, helped participants to locate the ball easier and manipulate it more intuitively. The second interface is a tilting-plate compliance display device, which replicates the compliance property of deformable and nondeformable virtual objects. This tactile display utilizes two tilting plates that create a first-order approximation of the concavity that is created when pressing on a compliant object. Despite its simple design and compact packaging, the compliance display device can provide a high-range of stiffness levels from 100 N/m up to rigid surfaces. The tilting-plate device is suitable for integration within devices such as robotic surgery consoles or cell phone touch screens