Automatic buoyancy compensator with electronic vertical motion

A method to maintain an established neutral buoyancy state of a diver, the method comprising:

• acquiring sequential pressure measurements, using a pressure measurement means, to identify a pressure change, which occurs when said diver changes depth;
• maintaining an estimate of air mass in an expandable displacement chamber, which is exposed to the water and attached to said diver;
• maintaining an estimate of temperature of the air in said displacement chamber;
• computing the change in air volume in said displacement chamber caused by the change in depth of said diver, by using said pressure measurements, the air mass estimate and the air temperature estimate of the air in said displacement chamber;
• and
• adjusting said air volume in said displacement chamber, using a gas valve means to add air to said displacement chamber or release air from said displacement chamber, to attain a neutral buoyancy air volume, whereby said neutral buoyancy state of said diver is maintained.

A method to provide vertical motion control for a diver, the method comprising:

• acquiring sequential pressure measurements, using a pressure measurement means, to determine the rate of change in pressure of the surrounding water as said diver moves vertically;
• maintaining an estimate of air mass in a flexible displacement chamber, which is exposed to the water and attached to said diver;
• maintaining an estimate of temperature of the air in said displacement chamber;
• using said rate of change in pressure of the surrounding water to compute said diver's vertical velocity;
• comparing the difference between the vertical velocity of said diver and a predefined vertical velocity;
• using the pressure measurement data, the air mass estimate, the temperature estimate, and the vertical velocity comparison to compute a new air volume in said displacement chamber which will reduce the velocity difference between the vertical velocity of said diver and said predefined vertical velocity;
• and
• adjusting the air volume in said displacement chamber, using a gas valve means to add air to said displacement chamber or release air from said displacement chamber, to attain said new air volume, whereby said velocity difference is reduced.