Aiming at the buoyancy and posture changes of the underwater robot during operation,a bidirectional variable volume buoyancy regulator was developed to reach the requirements of small size and large volume ratio.An experimental device was designed to verify whether the buoyancy and torque changes of the buoyancy regulator met the expected goals.STM32ZET6 single-chip microcomputer was used as the main controller of the embedded control system,and the interactive interface of the water surface control system was written in Visual Studio;periodic signals with different forms and frequencies were used as the desired trajectory to test the tracking performance of the buoyancy regulator,the effectiveness of the PID controller was verified through the pool experiment.The results show that the buoyancy regulator tracking cutoff frequency is 1/30 Hz.