Patent Document ID: 9878885
Application ID: 14322459
Patent Flag: 1

Claim One:
1. A crane controller for semi-automatic control of a rotary crane, the crane comprising at least a slewing actuator for creating a slewing motion of the crane and/or a luffing actuator for creating a luffing motion of the crane, and the crane controller comprising an input unit which can be operated by an operator to provide a desired slewing speed and/or a desired luffing speed as an operator input, a model-predictive reference trajectory planning module comprising an optimization unit for calculating a reference trajectory that obeys the system dynamics and follows the operator input, and a feedforward-controller using the reference trajectory for controlling the slewing actuator and/or the luffing actuator, wherein the optimization unit takes into account deflection of a rope of the crane in a tangential and/or radial direction when solving an optimization problem that provides the reference trajectory, and the crane controller further comprises a fallback trajectory planning module, wherein the fallback trajectory planning module calculates a feedback solution based on a summation of a deceleration part and a continuation function, the feedback solution is used by the feedforward controller if the optimization unit of the model-predictive reference trajectory planning module does not provide the reference trajectory within a predefined time-frame, wherein the deceleration part is calculated to ensure reference trajectory comes to rest, and the continuation function linearly reduces from an initial value toward zero to prevent abrupt changes in operation of the crane.