Attitude control system and method for spherical underwater robot

The invention discloses an attitude control system and method for a spherical underwater robot. The control method comprises the following steps: establishing a kinetic model of the spherical underwater robot; constructing a sliding-mode robust controller based on a sliding-mode control theory, inputting an expected position and an actual position of the spherical underwater robot into the sliding-mode robust controller, and obtaining control outputs in x, y and z axis directions; calculating expected attitude angles phi d and theta d of the spherical underwater robot according to the control output and the current attitude angle obtained in the step 2; calculating an attitude error according to the expected attitude angle and the actual attitude angle of the spherical underwater robot; respectively constructing a sliding mode surface according to the dynamic model and obtaining an equivalent control law; and designing a Lyapunov function and proving the stability of the sliding mode robust controller through