Optimum Design of Automatic Depth Control System for Underwater Divers

This study deals with the development of an automatically controlled depth-seeking system that enables the scuba diver to reach and maintain a predetermined depth. The system utilizes an inflatable life vest as a buoyancy-compensating element. The buoyancy of the vest is regulated by two on-off solenoid values that are controlled by depth and depth rate signals to improve stability. The valves and the depth-sensing pressure transducer are enclosed in a pneumatic control box that can be easily strapped to the diver’s waist and is controlled by an electronic control console carried by the diver. The system is operated by constant pressure air tapped from the diver’s air regulator. A theoretical model is developed to select the system design parameters which optimize its overall performance. Several tests of the device showed its excellent potential as a practical tool for the working divers. Besides its capability of maintaining a predetermined depth, it can be used in conjunction with a decompression meter to control the depth of the diver during the different decompression stages. The optimum design formulation with the selected parameters and merit criterion have provided an effective rational procedure for the design of this type of system.