Needle pose adjustment based on force information with needle puncturing robot

In recent years, interventional radiology (IR) which is a medical procedure has been attracting considerable attention. Doctors can perform IR percutaneously while observing the fluoroscopic image, such as CT and MRI images, of patients. Therefore, this surgical method is less invasive. However, doctors are exposed to strong radiation in the case of CT-guidance. In order to overcome this problem, we have developed remote-controlled IR assistance robot. The phenomena that the needle tip deviates from target tissue at the end sometimes occur, even if the needle is aligned with target tissue before puncturing. In this research a method to adjust pose of a needle in lateral direction based on information of force sensor for reducing deflection of needle is proposed. First, deflection of needle was modeled as a simply cantilever beam. Next, pose of needle gripper of robot to reduce the force is calculated. Finally, validity of the proposed method was verified based on the result of phantom puncture experiment.