A technique is provided for processing well fluid downhole. The guiding element includes a structure, one or more inlets, an outlet, and a transportation region. The bracket opening extends through the peripheral wall in places to allow the edge of the picket to extend out of the bracket on opposite sides. A compensation signal transmitter ensures that additional vibration of the mass is suppressed, by controlling actuators. It is determined whether the vehicle behavior is deteriorated based on the yaw rate difference.