Motion modeling and simulation of a flexible needle system with a piezo-actuated tip

Flexible needle insertion is a promising technique in biopsy therapy and intervention treatment. In this paper, a novel flexible needle system is proposed based on mechatronics system design and synthesis. The proposed flexible needle system is separated into two parts, i.e. a needle body and an actuated tip. The needle tip is actuated by the shear piezoelectric actuators based on stick-slip motion principle. In the conventional design, the needle tip can be rotated since the needle body transmits the motion from the needle base. However, the rotation accuracy suffers from the friction torque which is generated between the needle body and the surrounding tissue. One of the main advantages of the proposed design indicates that the needle tip is directly driven at tip end instead of at base end, which avoids the uncertainties such as friction disturbance. In this paper, the conceptual design of the proposed system is introduced first, and based on that, a detailed dynamic model is also discussed, which is validated by the numerical simulation.