Method for controlling the orientation of a crane load and a boom crane

1. A method for controlling an orientation of a crane load via a crane system with a manipulator for manipulating the load connected by a rotator unit to a hook suspended on ropes, comprising:

controlling a skew angle of the load by a control unit of a crane, wherein the control unit is an adaptive control unit wherein an estimated system state of the crane system is determined with a nonlinear model describing skew dynamics during operation;

wherein nonlinearity of the model describing the skew dynamics includes a nonlinear relation between a load deflection angle and a resulting reactive torque, wherein the nonlinear model is independent of load mass or a moment of inertia of the load mass, and wherein the estimated system state includes an estimated skew angle and/or a velocity of the skew angle and/or one or more parasitic oscillations of a skew system.

2. The method according to claim 1 , wherein the control unit includes a controller programmed therein including a 2-degree of freedom control comprising a state observer for estimation of the system state, a reference trajectory generator for generation of a reference trajectory in response to a user input, and a feedback control law for stabilization of the nonlinear skew dynamic model.

3. The method according to claim 2 , wherein the state observer receives measurement data from sensors comprising at least a drive position of the rotator unit and/or an inertial skewing rate and/or a slewing angle of the crane.

4. The method according to claim 2 , wherein the state observer is a Luenberger-type state observer.

5. The method according to claim 2 , wherein the state observer is implemented without a Kalman filter.

6. The method according to claim 2 , wherein the reference trajectory generator calculates a nominal state trajectory and/or a nominal input trajectory which is consistent with the skew dynamics and/or rotator drive dynamics and/or measured crane tower motion.

7. The method according to claim 6 , wherein a simulation of the nonlinear skew dynamic model and/or a simulation of the rotator unit is/are implemented at the reference trajectory generator for calculation of a nominal state trajectory and/or a nominal input trajectory consistent with crane dynamics.

8. The method according to claim 7 , wherein a disturbance decoupling block of the reference trajectory generator decouples the skewing dynamics from the crane's slewing dynamics.

9. The method according to claim 8 , wherein the reference trajectory generator enables an operator triggered semi-automatic rotation of the load of a predefined angle.

10. The method according to claim 1 , wherein control of the skewing angle is decoupled from a slewing gear and/or a luffing gear of the crane.

11. The method according to claim 1 , wherein the crane system includes a boom crane.

12. The method according to claim 1 , wherein the crane system includes a mobile harbour crane.

13. A method for controlling an orientation of a crane load via a crane system with a manipulator for manipulating the load connected by a rotator unit to a hook suspended on ropes, comprising:

adjusting a skew angle of the load with an actuator via a control unit of a crane having an adaptive digital controller, the control unit including instructions stored therein for reading information from one or more sensors, estimating a system state of the crane with a nonlinear model describing skew dynamics during crane operation, wherein the skew angle is adjusted based on the estimated system state, and wherein the crane system includes a boom crane.

14. The method of claim 13 , wherein the crane system further includes a spreader, the method further comprising automatically damping pendulum oscillations with an anti-sway system including damping torsional oscillations with a rotational actuator in response to operating parameters, wherein the skew angle is not restricted to a limited angle range.

15. The method of claim 14 , wherein the skew angle includes rotation of the spreader and crane load around a vertical axis with respect to ground, with the vertical axis arranged in a direction of gravity.