Modeling and experiments on a legged microrobot locomoting in a tubular, compliant and slippery environment

This paper presents the concept and preliminary modeling of a legged microrobot locomoting in a tubular compliant and slippery environment. The envisaged application field is related to capsular endoscopy. i.e., the development of a mobile swallowable capsule for navigation inside the gastrointestinal tract for diagnosis and therapy. After introducing and discussing the issue of autonomous locomotion of endoscopic devices, with reference to worldwide ongoing research in the field, the legged solution is proposed and peculiarities of this approach are described. The importance of simulation for developing a legged device is discussed and a locomotion model is presented. Experimental results are described for the definition of biomechanical parameters necessary in the model. Thanks to this work first simulations have been obtained, in which the microrobot's body moves according to arbitrary gait patterns for the legs and to its interaction with tissue. The resulting tool will be used for the design synthesis, for defining the optimal number of legs and the best number of degrees of freedom for each leg. It will be also used for controlling the device, by identifying the gait pattern to be adopted in order to obtain different capsule movements.