The design and realization of micro robotic devices in the medical field enable the operating gesture to be assisted. So a polyarticulated device actuated with shape memory alloy (SMA) springs for endoscopy is developed in collaboration with the Laboratoire de Robotique de Paris. In this paper, a simulator realization, based on an original simulation platform (OpenMASK), of this structure is described. A numerical representation of the inspected network obtained by magnetic resonance imaging is used. A contact detection algorithm, which will be described, allows to determine the interaction forces between the endoscope and the duct thanks to a distance cartography of the space, in order to minimize the calculation time. An important experimental work shall be lead to determine the parameters of the contact model. Simulation results of virtual navigation through this duct representation by using an endoscope mechanical model including a behaviour description of the SMA actuators will be presented. Moreover, the efficiency of a command with the multi-agent approach is proved. Then the simulator interest is studied for the prototype amelioration by applying the techniques of virtual prototyping. Some results of optimization by using genetic algorithms with respect to the virtual navigation task will be shown.