A novel magnetic levitation haptic device for augmentation of tissue stiffness perception

In medical training especially in palpation surgery, it is important for surgeons to perceive tissue stiffness. We design a novel magnetic levitation haptic device based on electromagnetic principles to enhance the perception of tissue stiffness in a virtual environment. The user can directly sense virtual tissues by moving a magnetic stylus in the magnetic field generated by the coil array of our device. To fully use the effective magnetic field, we devise an adjustable coil array and provide a reasonable explanation for such design. Moreover, we design a control interface circuit and present a self-adaptive fuzzy proportion integration differentiation (PID) algorithm to precisely control the coil current. The quantitative experiment shows that the experimental and simulation data of our device are consistent and the proposed control algorithm contributes to increasing the accuracy of tissue stiffness perception. In qualitative experiment, we recruit 22 participants to distinguish tissues of different stiffness and detect tissue abnormality. The experimental results demonstrate that our magnetic levitation haptic device can provide accurate perception of tissue stiffness.