Showing papers by "Yili Fu published in 2008"

Research on the axis shape of an active catheter

Abstract: Background An active catheter is a minimally invasive surgery catheter that can perform deflectable motions. The active catheter can be controlled from outside the body and moves like a snake, utilizing a multi-joint mechanism with distributed shape memory alloy (SMA) actuators. Methods It was considered that the deflection curve of the axis of the catheter is determined by the output force of the SMA actuators. Based on the large deflection theory, the deflection curve equation of the axis of the catheter was derived, using the precise form of the curvature. Results Through experimentation, the axial bending curve shape of the blended active catheter was measured precisely, and the experimental results were compared with the calculation results obtained from the large deflection theory and the circular arc hypothesis. The experimental results show that the curves calculated by large deflection theory are very close to the actual axis curves. Conclusions An active catheter prototype has been designed using the theory presented in this paper. Utilizing a vascular model, the active catheter-based invasive surgery was simulated. The experiment confirmed that the large deflection theory calculation method can be used to guide the design of the active catheter. Copyright © 2008 John Wiley & Sons, Ltd.

A wheel-leg hybrid wall climbing robot with multi-surface locomotion ability

Abstract: A prototype of wheel-leg hybrid mobile robot that can move on both ground and wall surfaces is presented, which could be used for special tasks such as rescue, inspection, surveillance and reconnaissance. The wheel-leg hybrid locomotion mechanism enable the robot to achieve quick motion on wall surface, as well as obstacle-spanning on wall surfaces and smooth wall-to-wall transitions. And the wheel lifting mechanism enables the robot to move on both wall surfaces and ground. The robot is composed of a base body and a mechanical leg with 3 DOF. The base body is a big flat suction cup with three-wheeled locomotion mechanism inside, and there is a small flat sucker in the end of the mechanical leg. The new designed chamber seal has simple structure and has steady and reliable performance. A distributed embedded control system is also described which enable the robot operating manually and semi-autonomously in wheeled motion mode or legged motion mode. Kinematics model of the robot is established to analyze the robot's motion on the wall. And the locomotion gait of the robot is discussed. Experiments show that the robot can adhere on wall surface and realize the basic movements.