This paper proposes a new type of microrobot that can move along a narrow area such as blood vessels which has great potential for application in microsurgery. Also, the development of a wireless microrobot that can be manipulated inside a pipe by adjusting an external magnetic field has been discussed. The model microrobot utilizes an electromagnetic actuator as the servo actuator to realize movement in biomedical applications. The structure, motion mechanism, and evaluation characteristic of motion of the microrobot have been discussed, and the directional control can be realized via the frequency of the input current. The moving experiments have been carried out in branching points in the horizontal direction, and the moving speed of the robot has been measured in vertical direction by changing frequency. Based on the results, the microrobot has a rapid response, and it can clear out dirt which is adhering to the inner wall of pipe. This microrobot will play an important role in both industrial and medical applications such as microsurgery.

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This paper proposes a novel master-slave robotic catheter operating system with force feedback and visual feedback for vascular interventional surgery (VIS). The robotic catheter system has good manoeuvrability, it can transmit the surgeon's skill to insert and rotate the catheter and avoids danger during VIS using force and visual feedback. In addition, it can be used to train unskilled surgeons to perform VIS. We performed a simulation experiment to validate our system using an endovascular evaluator (EVE). The experimental results demonstrated that the stability and response of the system were good. The robotic catheter system is suitable for performing VIS.

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This paper proposes a master-slave catheterisation system including a steerable catheter with positioning function and an insertion mechanism with force feedback. The steerable catheter is integrated with two magnetic tracking sensors for positioning. The distal shape of catheter is displayed with virtual vascular model to generate 3D guiding image to provide the relative relationship between the catheter and its surrounding vessels. The master-slave insertion mechanism with differential gear structure is designed with force feedback to assist surgeons to manipulate the catheter. It can implement pulling/pushing, rotating and bending/recovering the catheter. Based on this system, surgeons in the control room can utilise the master handle to operate the insertion mechanism for positioning the distal end of catheter with the assistance of 3D guiding image. The stability and accuracy of the system is validated in-vitro.

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A variety of microrobots have commonly been used in the fields of biomedical engineering and underwater operations during the last few years. Thanks to their compact structure, low driving power, and simple control systems, microrobots can complete a variety of underwater tasks, even in limited spaces. To accomplish our objectives, we previously designed several bio-inspired underwater microrobots with compact structure, flexibility, and multi-functionality, using ionic polymer metal composite (IPMC) actuators. To implement high-position precision for IPMC legs, in the present research, we proposed an electromechanical model of an IPMC actuator and analysed the deformation and actuating force of an equivalent IPMC cantilever beam, which could be used to design biomimetic legs, fingers, or fins for an underwater microrobot. We then evaluated the tip displacement of an IPMC actuator experimentally. The experimental deflections fit the theoretical values very well when the driving frequency was larger than 1 Hz. To realise the necessary multi-functionality for adapting to complex underwater environments, we introduced a walking biomimetic microrobot with two kinds of motion attitudes: a lying state and a standing state. The microrobot uses eleven IPMC actuators to move and two shape memory alloy (SMA) actuators to change its motion attitude. In the lying state, the microrobot implements stick-insect-inspired walking/rotating motion, fish-like swimming motion, horizontal grasping motion, and floating motion. In the standing state, it implements inchworm-inspired crawling motion in two horizontal directions and grasping motion in the vertical direction. We constructed a prototype of this biomimetic microrobot and evaluated its walking, rotating, and floating speeds experimentally. The experimental results indicated that the robot could attain a maximum walking speed of 3.6 mm/s, a maximum rotational speed of 9°/s, and a maximum floating speed of 7.14 mm/s. Obstacle-avoidance and swimming experiments were also carried out to demonstrate its multi-functionality.