Development of an active catheter by using IPMC (Ionomeric Polymer-Metal Composite)

• Main Authors: Po-Kae Fung, 方柏凱
• Other Authors: Ming-Shaung Ju
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/76186133119251148739

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 93 === 　Cardiac catheterization is a common minimum invasive surgical procedure for treating the cardiovascular diseases. The development of active catheter could alleviate the need to frequently change guide wires during the surgery. The main goal of this study is to develop an active guide wire (dim. 1 ~ 2 mm) by using ionomeric polymer-metal composite (IPMC). 　In this work, first, a novel fabrication method for IPMC film was developed and a testing system was set up to test the mechanical properties and performance of the IPMC actuator. Second, empirical model of the IPMC actuator was identified and fitted with an ARMAX model. Performances of open-loop and closed-loop controls of the IPMC actuator were compared for the overshoot percentage and the settling time. The prototype was tested on a conduit (dim. 3 mm) which has a Y-junction and a T-junction. 　The new metal replacement electroless plating method developed in this thesis can yield IPMC film (20 x 5 x 0.2 mm) with good electro active properties. From both analytical and FEM analyses, we found that the Young’s modulus of the composite film depends on the cubic power of the ratio of thickness of Nafion to that of the metal film. The IPMC actuator was a time-varying third order system. The bending angle of the active guide wire is proportional to the applied voltage. Bandwidth of the active guide wire system is about 3 ~ 4 Hz. By using the PID controller, the steady-state error for step response is less than 5% and the overshoot percentage is less than 5% and the settling time is about 0.4 seconds. The prototype active guide wire can go through the conduit system driven by applying a potential of 6 volts. 　The new fabrication process developed in this work has the advantages of shorter process time and simpler procedures when compared with existing methods. Bending angle of the guide wire can be accurately controlled by using the PID controller. Further miniaturization of the guide wire and combined with strain gage based curvature sensor by using the micro system technology may result in a complete active catheter system.