A 2-DoF Insertion Needle Using Inertia Piezoelectric Actuator And Motion Control

Insertion into delicate tissue is one of the most common biomedical operations.Some operations,such as vitreoretinal surgery,demand low force but high-resolution movements,which is arduous for human hands to achieve.Multiple actuation technologies,including electric motors,piezoelectric actuators,magnetic actuators,and thread actuators,have been applied and explored in this field.Each of these actuators features different exceptional characteristics,but some common drawbacks are also evident,including large volume,complicated structure or control signals,and relatively low movement range.The dissertation proposed a 2-Do F needle insertion device using inertia piezoelectric actuator for translational and rotational actuation of axially unsymmetrical arched fine needles for retinal vessel or cell insertion.The critical inertia actuation process was modeled and analyzed based on simulation.The characteristics and impact factors were discussed.The dimensions of the piezoelectric actuator's mechanical structures were obtained using the mechanics model and iterative optimization process of finite element analysis.A handheld controller was designed aiming to facilitate the control and application.The needle insertion device prototype was researched experimentally.Velocity,step size,step consistency,movement coupling,and force output of the actuator prototype were tested accordingly.The results showed that the needle insertion device could accomplish linear and rotary movement within a compact size,providing the insertion force of 32 m N.The motion range of linear movement was over 10 mm,and full rotation could also be achieved.The step size of t he linear movement under 120 V is 2.4?m.The maximum velocity equals 412?m/s with the step size variance coefficient of 4.23%.Rotary movement's step size under 120 V is 0.56 mrad.The highest rotating speed is up to 220mrad/s with the variance with the step size variance coefficient of 3.69%.The translational coupling movement in the rotational Dof is below 0.77?m,and the rotational coupling movement in the translational Dof is lower than 0.48?m.Wide motion range,micron stepping motion,reliable step size consistency,and stable force output guarantee the needle insertion device an ideal alternative for delicate tissue insertion.The handheld controller made the open-loop needle control reliable and straightforward.Cooperating with a macro actuator,such as a robotic arm,the 2-Do F needle could effectively alleviate the operational complexity,benefitting the operation efficiency and quality,showing great versatility and promising application potential.