| The modeling of contact interface, in which two entities are brought to interact with each other, either through direct contact or non-direct contact, is crucial in the understanding of robotics and biomedical research where such interface will determine important engineering properties. The modeling and analysis of direct contact interface and non-direct interface are studied in this dissertation, as applied in tonometry (non-contact) and skin sensors (contact). The stiffness of human organs or tissues is an important factor for medical diagnoses, and the accurate measurement of contact properties are very important. For instance, cancerous tissue has higher stiffness, and stiffer eyeballs with higher Intra-Ocular Pressure (IOP) have higher risk of glaucoma. In principle, the stiffness is estimated by measuring the deformation due to an applied force. Tonometry refers to a technique to measure the IOP of eyes, including that with a direct contact, such as the Goldman Applanation tonometry, or non-direct contact, such as the air-puff tonometry. The non-direct contact interface in the air-puff tonometry is analyzed and modeled to enhance the accuracy of IOP measurement in this dissertation. In addition, human organs or tissues demonstrate time-dependent responses of viscoelastic phenomena which affect the estimation of the stiffness and other engineering properties. Furthermore, prototypes of artificial skin, inspired by human skin, are fabricated to study the viscoelastic property and other engineering properties by different types of stimuli. The responses are also compared with those of biological skins in the context of interface with direct contact. |
