A fuzzy control algorithm is adopted to help the needle hit the target more accurately.The experimental setup for the needle insertion is built up to validate the algorithm.How the forces during the insertion make the needle deflect away from the planned path is given,and the normal method correcting the deflection is obtained accordingly.Because the normal method cannot perform well for correction,a fuzzy controller is established.The input module,output module,fuzzification module,defuzzification module and inference engine for the controller are given respectively according to the fuzzy theory.Our experimental results show that the fuzzy controlling system presenting in the paper can better eliminate the deflection.
In order to improve the effectiveness of percutaneous diagnosis and therapies,the needle insertion into the deforming soft and inhomogenous tissue should be accurate. In this study a needle with 6 degrees of freedom force / torque sensor is used to find the relationship between the pathway's length and the force. Our experiments show that the method with repeated extraction-insertion cycles can make the needle approach the target as much as possible. M eanwhile ! a method to obtain the appropriaterepeated extraction-insertion cycles is given to drive the needle to execute the repeated cycles efficiently. Experiments and discussions were conducted to preliminarily validate the method.
