To research the automatic mechanisms’ law of motion
the velocity measurement system of the underwater gun’s automatic mechanisms is composed of the sensor mounted in the experimental equipment and other measurement instruments.The composition and working law of the induction velocity measurement sensor and some critical problems about underwater velocity measurement have been analyzed and discussed.By the measurement system
the velocity of automatic mechanisms has been measured.The preliminary analysis of experimental phenomenon has been made according to the measured data.It has been found by experiment that the measurement system has good insulation property and a flat frequency response from a few cycles per second to several thousand cycles per second
and is able to meet the particular needs of the velocity measurement of the underwater gun’s automatic mechanisms.