Design and Qualification of a Latching System for Experimental Undercarriage System for 6000 m depth

Abstract

India has been developing technology for deep sea mining to harvest polymetallic nodules from the Central Indian Ocean Basin (CIOB). As the seabed soil is very soft in nature, developing the mining machine for maneuverability with controlled slippage is very critical. Estimating the forces acting on the mining machine is important for developing the locomotion system of the same. An Experimental Under-carriage has been developed for qualifying the traction and measuring the resistance parameters. The flexible riser-umbilical exerts considerable dynamic load on the mining machine during locomotion. This paper presents the design, analysis and functional qualification of a latching system of the Experimental under-carriage (EUC) locomotion system which is used to measure these riser dynamic loads at various stage of the locomotion. Underwater load cells with high sensitivity are used to measure the riser loads on the system. These load cells however cannot handle the large loads during deployment and retrieval. To isolate the load cell during launching and retrieval, a latching system has been developed. It has been made fail safe to operate when power and communication link fail. The load cells have been qualified in hyperbaric chamber for various load and pressure conditions. A multibody dynamic analysis has been undertaken in Automatic Dynamic Analysis for Mechanical Systems (ADAMS/View) for evaluating the configuration, mechanism of closing and the reaction forces under various conditions of launch and retrieval. The complete system has been analyzed in Finite Element Method using ANSYS by applying the reaction forces from ADAMS/view and the weak points identified and corrected. A functional prototype was developed and tested under various loading conditions and analyzed for operation and strength.