Compared to conventional vibration actuators, such as an electric motor or an inertial mass shaker, a soft actuator with electro-hydraulic characteristics may produce delicate vibration. However, this actuator can cause some problems, including high driving voltage, low excitation force, and a short life cycle, to vehicles. This paper proposes a new type of soft actuator that uses a polymer gel film to address these problems, and a control system with a rapid switching speed to generate target vibration. Additionally, a synthesis method of the control signal is suggested to generate vibration linked to sound through the actuator and the control system. The suggested system is applied to a steering wheel to generate haptic vibration in a vehicle. This system has significantly improved the output, driving voltage, and durability, and emits soft vibration.