Aiming at the control problems of translational oscillations with a kind of rotational actuator(TORA) system, a self-coupling proportional-integral-differential(SCPID) control method is used. Firstly, the centroid of the TORA system is mapped to the vibration center of Huygens by coordinate transformation, so that the control input of the new system is decoupled and zero dynamic instability is avoided. Then the SCPID controller for the translation position is designed with the Huygens vibration center, the virtual command of the ball deflection angle is obtained at the same time, and the SCPID controller of the ball deflection angle is designed, so as to realize the equilibrium point tracking control of the TORA system. Finally, the stability of the closed-loop control system is analyzed and proved strictly in complex frequency domain. Simulation results and comparison with other methods show that the control algorithm designed is simple and efficient, and has practical application value in the field of underactuated control system.