Jong-Su Choi

A Self-Propelled Deep-Seabed Miner and Lessons From Shallow Water Tests

A self-propelled miner for deep-seabed manganese nodules was developed for the purpose of evaluations of mining performance and viability for scale-up. The test miner crawls on the seafloor by two tracks and separates the nodules from seafloor by hybrid pick-up device. The weight and size are 10tons in air (5tons in water) and 5m(L)×4m(W)×3m(H), respectively. It is operated electro-hydraulically in real-time via umbilical cable. Software’s for real-time remote control, monitoring and database systems were developed as well. Shallow water tests of the test miner were performed in 100m water depth of an inshore condition site. Glass beads (d = 19mm, m = 10g/ea) were made for artificial nodules instead of real nodules. Non DP barge (W = 19m, L = 51m) was used as surface unit. The sea tests showed that the fundamental performance of the test miner is confirmed and at the same time functional modification and improvement in sensing and measurement system are addressed. This paper describes about the development methods of the test miner and lessons from the sea tests.© 2010 ASME

Path Tracking using Vector Pursuit Algorithm for Tracked Vehicles Driving on the Soft Cohesive Soil

Generally, tracked vehicles are used in military, agricultural and recreational applications where terrain conditions are improper or unpredictable. Tracked vehicles are better than wheeled vehicles due to the larger contact area of tracks providing better floatation and traction at various ground conditions. In this paper, the path tracking method is proposed for tracked vehicle driving on the deep-sea soft cohesive soil. Firstly, to generate the vehicles motion following the specified path, the vector pursuit algorithm is used. Next, to drive the vehicle as the generated motion, the control method based on the relation between the traction force and the track slip is proposed. Finally, to prove the performance of vector pursuit algorithm, the numerical simulation is done. Also, to directly induce the relation of traction force-slip, the draw-bar pull test is executed

Performance Analysis of Deepsea Manganese Nodule Test Miner in Inshore Tests

Inshore tests were performed in order to verify the design concept of deep sea manganese nodule miner at a site near Hupo at East Sea of Korea in June of 2009. Total mining tests of the test miner, named ‘Minero ® ’, together with flexible hose, lifting pump and lifting hose were accomplished. In this study, the performances of three subsystems of testminer (vehicle, pick-up device, and launch-and-recovery device) were analyzed for feasibility assessment of self-propelled remotely controlled miner, and also to compile basic data for designing a pilotminer. Performances of the test miner were defined based on the Functional Requirements of Axiomatic Design. The inshore tests revealed that the test miner generally satisfies the functional performances. Feasibility assessment and reflection on results are discussed within.

Total Dynamic Analysis of Deep-Seabed Integrated Mining System

본 논문은 통합채광시스템의 동력학 해석을 다루고 있다. 통합채광시스템은 채광선, 수직양광관, 중간 저장 장소인 버퍼, 유연관, 자항식집광기로 구성되어 있다. 자항식집광기와 버퍼는 6자유도의 강체로 가정하였으며, 수직양광관과 유연관의 동적거동 해석을 위해 집중질량 매개방법을 이용한 이산화 모델을 적용하였다....

Damage Detection Using Finite Element Model Updating

In this study, a damage detection method that uses sensitivity-based finite (FE) element model updating with the natural frequency and zero frequency was proposed. The stiffness matrix for a structure was modified using the sensitivity-based FE model updating method. A sensitivity analysis was used to update the FE model, and the natural frequencies and zero frequencies were considered as target parameters to supplement the information on the vibration characteristics. The locations and values of the damages were estimated from the modified stiffness matrix. Several numerical examples were considered to verify the performance of the proposed method.

An Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Soft Sediment Based on Design of Experiment Using Orthogonal Array

Abstract : This paper is concerned with an experimental investigation about tractive performance of atracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of 0.9 m(L) ×0.75 m(B) × 0.4 m(H) and the weight of 167 kg was constructed with a pair of driving chain links driven bytwo AC-servo motors. The tracks are configured with detachable grousers with variable span. Deep seabedwas simulated by means of bentonite-water mixture in a soil bin of 6.0 m(L) × 3.7 m(B) × 0.7 m(H). Slip ofvehicle and driving torque of motor were measured with respect to experimental variables; grouser span,grouser chevron angle, driving speed, drawbar-pull weight, position of center-of-gravity and weight. L 8 orthogonal array is adopted for DOE (Design Of Experiment). The effects of experiment variables ontraction performance are evaluated.Key words : (cohesive soil), (tracked vehicle), (orthogonal arrays), (Design Of Experiment), (grouser), (drawbar-pull test), (slip), (driving torque)

Metamodel-Based Multidisciplinary Design Optimization of a Deep-Sea Manganese Nodules Test Miner

A deep-sea manganese nodules test miner has not only coupled relationship between system components but also various design requirements of each system to meet the specified multitasks. To accomplish the multiobjectives of complex systems, multidisciplinary design optimization (MDO) is performed. Metamodels such as the kriging model and the response surface model are employed to reduce computational costs for MDO and to integrate component systems in a design framework. After verifying the accuracy of each metamodel, metamodel-based MDO for a deep-ocean test miner is formulated and performed. Finally, results and advantages of the proposed design methodology are discussed.

Study on underwater navigation of crawler type mining robot

In South Korea, a self-propelled mining robot, named MineRo, was developed in 2007. In 2009 and 2010, shallow water tests in around 100m depth have been executed for the purpose of evaluations of collecting, lifting and driving performance. Particularly, in the 2010s test, a path tracking control of the robot was performed near harbor Hupo at East Sea of South Korea. For the path tracking control, most of all, the underwater navigation informed robots position should be ensured. This paper proposes two navigation algorithms, dead-reckoning and extended kalman filter(EKF) based on the kinematics of robot. Firstly, the kinematic parameters, such as slip and slip-angle are calculated from velocity of DVL and yaw-rate in real time. In case of dead reckoning, the position is directly estimated from the kinematics substituting the parameters. In EKF, by applying the parameters to the Jacobian matrix, the accuracy is improved. The performances of two algorithms are verified through simulation using the data of various driving test of the robot.

A Study on the Contact Response Analysis Technique for Marine Slender Structure

Dynamic analysis of a marine slender structure is often involved with contacts among bodies or between bodies and seafloor. This paper presents an efficient and general contact search algorithm for dynamics in the context of the compliance contact model. A global detecting method that a bounding box is divided into several pieces in global coordinate system is presented in this paper. The method has an advantage that the number of contacting searching am be smaller than other methods for a system. The developed an efficient contact search algorithm is applied to the simulation program of 3D nonlinear dynamics of slender structure. Some examples are presented to show the validity of the proposed method.

Steering performance test of underwater mining robot

A pilot-scale mining robot for manganese nodule has been developed by KRISO (Korea Research Institute of Ships and Ocean Engineering) in 2012. The robot consists of two unit-modules having an identical mechanical and hydraulic configuration. Each unit module has two tracks, two pick-up devices with attitude control devices, two crushers, one discharging pump, and hydraulic system. In 2013, Sea-trial has been performed at 130m depth in the east sea of South Korea. To strictly keep and follow the pre-defined complex path with a constant forward speed, steering characteristics of the mining robot are required. To know the characteristics of the robot, steering performance test was executed with appointed steering ratios. Also, for the reliable driving of the robot, the velocity pattern of four-columns tracks is determined by numerical simulation. To actuate track motor as a commanded velocity, PI controller is designed from system identification method and gain tuning rule.