Towards an analytic haptic model for force rendering of soft-tissue dissection

Both surgical simulation and robot-assisted surgery require haptic models of tool-tissue interaction for force rendering. Most efforts of haptic modeling have focused on characterizing tool-tissue interaction of soft-tissue indentation, insertion and cutting. Less attention has been devoted to soft-tissue dissection however. For the dissection, haptic models remain elusive to meet two requirements as: to represent nonlinearity of soft-tissue responses and to comply with the time constraint of 1 ms for force rendering. Hence, this paper presents a modeling framework towards developing an analytic haptic model for force rendering of the dissection. Based on estimation theories, the framework devises an analytic model to approximate an empirical force-distance profile of the dissection. Applying the framework to 2 different empirical profiles as use cases, the derived models estimated about 72% and 91% of the empirical data, respectively. Algorithm implementation of these models in Matlab yielded a computational time of about 24 μs, much less than 1 ms. The outcomes indicate a potential of using the framework to develop an analytic haptic model for force rendering of soft-tissue dissection.