Water level control of submarine hovering tank based on sliding mode control

Abstract

To achieve fast adaption in submarine hovering condition, the water level control of hovering ballast tank is crucial for quick adjustment of tank mass, and thus to exert extra hovering force on submarine. Based on the analysis of ballast tank system mechanism, mathematical model of blowing/venting process is firstly established. Since nonlinearity presents in tank system model, input-output feedback linearization is applied to deduce the exact linearized form of state law equations. Sliding mode control is then introduced to counteract parameter uncertainties in the transformed linearized system, and double exponential reaching law and sigmoid function are used in controller design to guarantee smooth transfer and rapid responses. Numerical simulation is conducted in Matlab to test performance of presented control scheme, and multidomain physical system Simscape is utilized for system modelling to enhance accuracy. Simulation results demonstrate that the control system is of satisfactory performance on water level control, as to fast tracking of set output and low air consuming.