Sang-Ki Jeong

Design and Control of 6 D.O.F(Degrees of Freedom) Hovering AUV

In this paper, a study of a new hovering six dof underwater robot with redundant horizontal thrusters, titled HAUV (hovering AUV), is presented. The results of study on the structure design, deployment of thrusters, and development of the developed control system of the AUV was presented. For the HAUV structure, a structure design and an analysis of the thrusting system was performed. For navigation, a sensor fusion board which can proceed various sensor signals to identify correct positions and speeds was developed and a total control system including EKF (Extended Kalman Filter) was designed. Rolling, pitching and depth control tests of the HAUV have been performed, and relatively small angle error and depth tracking error results were shown.

A study on an up-milling rock crushing tool operation of an underwater tracked vehicle

In this article, we develop the analysis of a new underwater tracked vehicle with rock crushing tool, working under the water. To design the capacity of the underwater tracked vehicle actuator and the rock crushing tool actuator, we analyze the interaction forces and torque between the rock and the rock crushing tool. Since experiments on the underwater tracked vehicle with a rock crushing tool are very difficult, costly, time-consuming, we first perform a mathematical modeling of the underwater tracked vehicle with the rock crushing tool. We analyze the mechanics of the underwater tracked vehicle system that is affected by the forces and moments of the underwater rock crushing, where the force and torque on the rock crushing tool are based on the analysis of the mechanics of an individual cutter tool. We derive a mathematical expression for the forces and moments of the combined system on the underwater tracked vehicle and the rock crushing tool for rock crushing. For this, we study the parameters that affect the mechanics of the underwater tracked vehicle system with the rock crushing tool. To apply the rock crushing tool to underwater rock excavation, we also study the hydrostatic effects to the combined underwater tracked vehicle system with the rock crushing tool. To design the capacity of the actuator of the developing underwater tracked vehicle and the rock crushing tool, we analyze the required tractive or down thrust forces, and the torque to the rotor carriage caused by the cutting system. In addition, we analyze the energy and the power for the rock crushing tool actuator related to the tool characteristics. To support the validity of the analyses, we use the derived equations to perform a number of numerical simulations.

Design of a new high speed unmanned underwater glider and motion control

In this paper, the design and control of a new underwater glider having a high horizontal speed was studied. For this, the capacity of buoyancy engine which performs 2.5(knots) horizontal speed was designed. Especially, a controllable buoyancy engine to regulate the amount of buoyancy was designed and developed for control of the pitching angle of UG and the mass shifter carrying the battery was designed for controlling pitching and yawing motion of the UG. A mathematical modeling based on six degree-of-freedom dynamics equation including the buoyancy engine and mass shifter dynamics was performed to control the UG. Using the mathematical model, a simulation of the yaw motion control of the UG is presented. A number of sea experiments were performed to verify the navigation performance of the developed UG.

Design and Implementation of Dynamic Positioning Control System for USV

Nowadays, the dynamic positioning (DP) performance of an unmanned surface vehicle (USV) is receiving special attention for marine research and surveying exploration in coastal areas. So, this paper describes a structure design of a USV disposed with three thrusters. With this disposition, by means of active thrust, the USV can be controlled at a fixed position with fixed heading. Also, hardware and software architectures of the control system are addressed and the functions of all parts are clarified. A strategy for DP control is presented to compensate the deviations due to disturbances from waves, wind, sea current, or sensor inaccuracy. Finally, according to this developed strategy, a number of experiments were performed through sea trials and the results will be shown.