Traction and drawbar pull experimental study for development of deep sea mining machine

Motion of tracked vehicles, especially on soil with shear strength less than 2 kPa under deep sea conditions is an ambitious area to envisage. A tracked deep sea mining machine is being developed to mine polymetallic nodules from 5000-6000 m water depth at the Central Indian Ocean where the sea bed has a very low soil strength. Experimental and numerical simulation studies were conducted on the tracked vehicle model to arrive at the optimum dimensions of the undercarriage of deep sea mining machine. An electro hydraulically driven tracked vehicle used for the experiments on traction studies. The tracked system model was run on a sandy terrain under different normal loads and the traction force was measured. Various parameters like hydraulic oil pressure at the motor inlet, oil flow and speed of the drive drum were measured using sensors through a data acquisition system (DAC system). A tension type load cell was used for the drawbar pull test to measure the maximum traction force offered by the soil. Another critical design parameter for the tracked vehicle moving on cohesive soil is the grouser which is interacting directly with the soil. The effect of vital parameters like pitch, height and inter teeth gap of the grouser teeth of the track belts were studied analytically and optimum configuration was selected based on the maximum shear area. The single track model was simulated numerically in Automatic Dynamic Analysis for Mechanical Systems (ADAMS) Tracked Vehicle (ATV) for evaluating the traction performance of the tracked vehicle and the same was validated with the experimental model under various loading conditions and operating speed. The methodology and results of experimental and simulation variables on traction studies and grouser analysis have been discussed in this paper.