A positioning system, for a boom having right and left boom arms (41, 51), comprises: a first actuator (40) for moving the right boom arm (41) relative to a support frame (30)； a second actuator (50) for moving the left boom arm (51) relative to a support frame (30)； a first hydraulic link (110； 310) between the first and second actuators (40, 50)； and a hydraulic control device (120； 320) for controlling movement of hydraulic fluid within the first hydraulic link (110； 310), thereby controlling extension and/or retraction of the first and second actuators (40, 50).
