The Design Of Capsule Robot Based On IPMC Actuator

Ionic Polymer-metal Composites(IPMC) is a new type of electro-active polymer(EAP) material, which deposited a noble metal on both sides of the Nafion polymer film by using chemical plating method. IPMC has the advantages of small volume, lightness, flexibility, can be driven under low voltage with large deformation and work in damp environment or water filled environment. Also IPMC has good biocompatibility. To solve the existing defects of clinical commercial capsule endoscopy, in this paper, we designed a kind of capsule robot driving by IPMCs in order to realize the active control of capsule endoscope in the body. The main contents include the following:1. Prepare IPMC actuators for the capsule robot. The IPMC actuators were fabricated by depositing platinum on the casting Nafion membrane using chemical plating. The thickness of IPMC is 0.3mm.2. Design of a portable IPMC actuator tester. In order to achieve the portability and convenience of the IPMC testing system, the power supply and control system of the tester were integrated into an electrode clamp. The tester can adjust the frequency, amplitude and wave form of the output signal. The signal’s accuracy is 0.1V, and the lowest frequency can be 0.1Hz. Meanwhile, the control system has a large load capacity to drive the IPMC, as the output current can be at least 200 m A. The measurement results showed that the design for the IPMC tester was correct and feasible.3. The design of the capsule robot. First of all, the capsule robot’s functional planning was discussed and divided into two parts: the active clamp and the active drive in human body. Secondly, according to the functional planning of the robot, the overall structure of the capsule robot was designed. The robot comprised a front cover, the main middle structure part, the tail structure parts, and was fabricated by using laser 3D print.4. The active control and test of the capsule robot. The caudal fin structure and driving mode of the robot was bionic optimization designed. We designed the flexible fin unit, and proposed two drive mode: single tail fin structure and double tail fin structure; According to the test result of the two driving modes, the maximum swimming speed is up to 7mm/s. Finally, the capsule robot’s functions were tested in simulated intestinal environment.