Guidance and Control of Biomimetric Underwater Robot with Mechanical Pectoral Fins

Abstract

This paper discusses guidance and control of an underwater robot equipped with 2 pairs of the mechanical pectoral fins by carrying out two kinds of the tank experiments in still water and in water currents. Fuzzy algorithms were used in the guidance and control. The first kind of the experiment was to guide the underwater robot from a far point to an underwater post by controlling the position both in the vertical plane and in the horizontal plane. In still water, the underwater robot was firstly guided to a waypoint located in the elongated longitudinal plane of the underwater post and was next guided to an underwater post. In water currents crossing the course of the underwater robot, the underwater robot was guided to the first waypoint located upstream from the longitudinal plane of the underwater post, and was next guided to the second waypoint located in the neighborhood of the underwater post by making the underwater robot drift downstream, and was finally guided to the underwater post. The second kind of the experiment was to guide the underwater robot around the surface of a circular cylinder by keeping the distance between the surface of the circular cylinder and the underwater robot constant and directing the head of the underwater robot to the center of the cylinder. In still water, lateral swimming control, distance control between the surface of the circular cylinder and the underwater robot, and azimuth control to direct the head of the underwater robot to the center of the cylinder were simultaneously performed by allotting the lateral swimming control to the fore mechanical pectoral fins and the distance control and the azimuth control to aft mechanical pectoral fins. In water currents, the underwater robot was firstly guided from an upstream start point to a downstream waypoint by making the underwater robot drift downstream along the water currents under the control of the azimuth control and the distance control, and was next guided from the downstream waypoint to the upstream start point by taking a roundabout course.