Haptic Playback: Modeling, Controller Design, and Stability Analysis

With new surgical tools and techniques being continuously introduced, efficient teaching of sensorimotor skills has become an important issue in surgical training. Sensorimotor skills are traditionally taught by a trainer who physically interacts with the trainee. This method is expensive and time consuming. Haptic playback represents an efficient solution to this problem allowing to simultaneously display position and force information to users. The traditional framework used in haptics does not well adapt to this task. This paper proposes a new framework that allows to formally address the issues deriving from simultaneously displaying force and position. This is achieved with the introduction of an information channel and the modeling of the operator as a MISO system. An intuitive and simple model for the user is proposed and validated through experiments with human subjects. The model is then used to design a control strategy, the crossed controller, that exploits both the haptic channel and the information one. The stability of the controlled system can be studied with formal methods. The performance of the crossed controller is finally tested against a more traditional controller through experiments with human subjects.