A system which operates hydraulically and comprises: - a pressure line for supplying pressurized hydraulic fluid; - a pump configured to supply pressurized hydraulic fluid to the pressure line; - an actuator connected to the pressure line, for receiving pressurized hydraulic fluid from the pressure line and for moving the actuator; - a valve device configured to control the flow of pressurized hydraulic fluid from the pressure line to the actuator, and the speed of the actuator; - an electronic control unit configured to monitor and control the functions of the system, to control the valve device by a control signal dependent on the speed of the actuator desired at any given time; - a pressure accumulator connected to the pressure line, from which the pressure accumulator is adapted to receive pressurized hydraulic fluid and to which the pressure accumulator is adapted to, simultaneously with the pump, supply pressurized hydraulic fluid for moving the actuator; the system being characterized by: - a sensor device (34, 36) configured to: - i. measure the pressure of the hydraulic fluid contained in the pressure line at any given time, and transmit a measurement signal proportional to the pressure of the hydraulic fluid, to the electronic control unit, the electronic control unit being configured to deduce the amount of hydraulic fluid in the pressure accumulator from properties of the pressure accumulator and the pressure of the hydraulic fluid; or - ii. measure, directly or indirectly, the amount of pressurized hydraulic fluid in the pressure accumulator at any given time, and transmit a measurement signal proportional to the amount of pressurized hydraulic fluid, to the electronic control unit, the sensor device being connected to the pressure accumulator; - setting devices configured to generate a setting signal and to set the control signal to be proportional with the targeted speed of the actuator at any given time; - the actuator being a linear actuator; and - the electronic control unit that is configured to restrict the targeted speed of the linear actuator not to exceed a predetermined maximum speed which is proportional to the amount of pressurized hydraulic fluid in the pressure accumulator. - a pressure line for supplying pressurized hydraulic fluid; - a pump configured to supply pressurized hydraulic fluid to the pressure line; - an actuator connected to the pressure line, for receiving pressurized hydraulic fluid from the pressure line and for moving the actuator; - a valve device configured to control the flow of pressurized hydraulic fluid from the pressure line to the actuator, and the speed of the actuator; - an electronic control unit configured to monitor and control the functions of the system, to control the valve device by a control signal dependent on the speed of the actuator desired at any given time; - a pressure accumulator connected to the pressure line, from which the pressure accumulator is adapted to receive pressurized hydraulic fluid and to which the pressure accumulator is adapted to, simultaneously with the pump, supply pressurized hydraulic fluid for moving the actuator; - a sensor device (34, 36) configured to: - i. measure the pressure of the hydraulic fluid contained in the pressure line at any given time, and transmit a measurement signal proportional to the pressure of the hydraulic fluid, to the electronic control unit, the electronic control unit being configured to deduce the amount of hydraulic fluid in the pressure accumulator from properties of the pressure accumulator and the pressure of the hydraulic fluid; or - ii. measure, directly or indirectly, the amount of pressurized hydraulic fluid in the pressure accumulator at any given time, and transmit a measurement signal proportional to the amount of pressurized hydraulic fluid, to the electronic control unit, the sensor device being connected to the pressure accumulator; - i. measure the pressure of the hydraulic fluid contained in the pressure line at any given time, and transmit a measurement signal proportional to the pressure of the hydraulic fluid, to the electronic control unit, the electronic control unit being configured to deduce the amount of hydraulic fluid in the pressure accumulator from properties of the pressure accumulator and the pressure of the hydraulic fluid; or - ii. measure, directly or indirectly, the amount of pressurized hydraulic fluid in the pressure accumulator at any given time, and transmit a measurement signal proportional to the amount of pressurized hydraulic fluid, to the electronic control unit, the sensor device being connected to the pressure accumulator; - setting devices configured to generate a setting signal and to set the control signal to be proportional with the targeted speed of the actuator at any given time; - the actuator being a linear actuator; and - the electronic control unit that is configured to restrict the targeted speed of the linear actuator not to exceed a predetermined maximum speed which is proportional to the amount of pressurized hydraulic fluid in the pressure accumulator.