Spring 2011 - Fall 2011. Minimally invasive surgery (MIS), where surgical tools are inserted into the body through small incisions, has recently moved in the direction of using small in vivo robotic devices. In vivo robots have a strong potential to make state-of-the-art MIS concepts, such as natural orifice translumenal endoscopic surgery (NOTES), a reality by providing for an unconstrained in vivo platform to visualize, manipulate and surgically treat tissue. However, the key to effective in vivo devices is mobility which is challenging: the surgical environment is dynamic due to respiration and other biological processes; in vivo mobility inevitably involves the interaction between tissues and device; and the tissue properties (viscoelasticity, fluid coatings, adhesion, terrain profile, etc) are different for each organ, each patient, and even at different points in the surgery as patient hydration and in vivo humidity levels change. To make in vivo robotics a reality, accurate tissue models and simulation methods need to be developed for future design optimization and faster testing of device concepts before going to animal studies. In this project, accurate tissue models will be developed for modeling contact mechanics for future locomotion system designs. The proposed work specifically includes: 1) experimental measurement of small bowel mechanical properties, and 2) peristaltic and tract constriction force measurements. These results will lead to combined modeling of the gastrointestinal (GI) tract including these properties, contact locomotion modeling, and experimental testing of prototype locomotion systems.