Method of controlling a pitching system (3a,b,c) of a rotating rotor blade (2a,b,c) of a wind turbine, the method comprising: controlling the pitching system (3a,b,c) such that unintended pitching (30,31,32,33) due to gravity is reduced, wherein controlling the pitching system (3a,b,c) comprises: determining a control signal (10a,b,c); supplying the control signal (10a,b,c) to the pitching system (3a,b,c), wherein the control signal varies in dependence of a rotational speed of the rotor, the control signal comprising a component being defined by a periodic waveform function having as a repetition period the revolution period of the rotor, wherein the control signal (10a,b,c) is determined based on a feedback signal (12a,b,c), wherein the feedback signal comprises: an actual blade torsion indicating signal indicating the actual torsion of the blade relative to a hub at which the blade is mounted, wherein the control signal is supplied to a blade pitch angle actuator (16a,b,c) adapted to set the pitch angle, characterized in that the blade pitch angle actuator comprises at least two pistons (36, 37) guided within two respective cylinders (38, 39) which are connected to a hydraulic system (40, 41) that is controlled based on the control signal, wherein the control signal is adapted to drive the pistons (36, 37) in order to reduce backlash, wherein the control signal is determined such that to drive the pistons (36,37): in different directions (47,48) towards restricting pitching movement, in case of torsion (Tb) fluctuating is around or close to zero; and in same direction enabling readjusting the pitch angle, if the torsion (Tb) is positive or negative. determining a control signal (10a,b,c); supplying the control signal (10a,b,c) to the pitching system (3a,b,c), wherein the control signal varies in dependence of a rotational speed of the rotor, the control signal comprising a component being defined by a periodic waveform function having as a repetition period the revolution period of the rotor, wherein the control signal (10a,b,c) is determined based on a feedback signal (12a,b,c), wherein the feedback signal comprises: an actual blade torsion indicating signal indicating the actual torsion of the blade relative to a hub at which the blade is mounted, wherein the control signal is supplied to a blade pitch angle actuator (16a,b,c) adapted to set the pitch angle, characterized in that the blade pitch angle actuator comprises at least two pistons (36, 37) guided within two respective cylinders (38, 39) which are connected to a hydraulic system (40, 41) that is controlled based on the control signal, wherein the control signal is adapted to drive the pistons (36, 37) in order to reduce backlash, wherein the control signal is determined such that to drive the pistons (36,37): in different directions (47,48) towards restricting pitching movement, in case of torsion (Tb) fluctuating is around or close to zero; and in same direction enabling readjusting the pitch angle, if the torsion (Tb) is positive or negative. an actual blade torsion indicating signal indicating the actual torsion of the blade relative to a hub at which the blade is mounted, wherein the control signal is supplied to a blade pitch angle actuator (16a,b,c) adapted to set the pitch angle, characterized in that the blade pitch angle actuator comprises at least two pistons (36, 37) guided within two respective cylinders (38, 39) which are connected to a hydraulic system (40, 41) that is controlled based on the control signal, wherein the control signal is adapted to drive the pistons (36, 37) in order to reduce backlash, wherein the control signal is determined such that to drive the pistons (36,37): in different directions (47,48) towards restricting pitching movement, in case of torsion (Tb) fluctuating is around or close to zero; and in same direction enabling readjusting the pitch angle, if the torsion (Tb) is positive or negative. in different directions (47,48) towards restricting pitching movement, in case of torsion (Tb) fluctuating is around or close to zero; and in same direction enabling readjusting the pitch angle, if the torsion (Tb) is positive or negative.