Method and system for controlling a parallel crane on a working machine

A method for controlling a parallel crane on a working machine by a Tool Center Point (TCP) control according to which method, the parallel crane has a crane arm system with crane parts, comprising at least a lifting arm section configured to provide a parallel operation of the crane tip to the foundation when the crane is operated inwards/outwards from the working machine, a rocker arm with a telescoping push arm, which crane parts are articulately, mutually connected and to the working machine and can be displaced relative to each other and to the working machine by the influence of actuators and activators that are controlled and monitored by a control system of the working machine, and in which method direction and motion speed are obtained for the parallel crane Tool Center Point (TCP), which is controlled by an operator using joysticks in the working machine, by applying speeds for the various crane parts of the parallel crane, wherein the speeds of the various crane parts of the parallel crane are automatically determined by the control system when the Tool Center Point (TCP) is operated in one of the following ways;

• outward or inward in a horizontal plane (xy) relative to the working machine;
• upwards or downwards in a vertical plane (xz, yz) relative to the working machine based on the position of the various crane parts relative to their mutual angle positions (q2, q3) and the telescope length of the rocker arm as well as through parameter adjustment of the speeds of the various crane parts by correction factor curves and based on at least one of the following measures;
• a) when the Tool Center Point (TCP) is run outwards relative to the working machine, the speed is restricted at which the push arm telescopes out from the rocker arm through parameter adjustment of the speed of the push arm based on the momentary angle position (q3) of the rocker arm;
• b) when the Tool Center Point (TCP) is run inwards relative to the working machine, the speed of the rocker arm is restricted on the momentary telescope length of the rocker arm until the telescope length falls below a predetermined stop length (d-stop) after which the telescope is turned off and the rocker arm acquires a 1:1 relationship to lever command;
• c) when the Tool Center Point (TCP) is run upwards relative to the working machine, the speed is restricted at which the push arm telescopes into the rocker arm through parameter adjustment based on the momentary angle position (q3) of the rocker arm;
• d) when the Tool-Center-Point (TCP) is driven downward relative to the working machine, the speed is restricted at which the push arm telescopes out from the rocker arm through parameter adjustment based on the momentary angle position (q3) of the rocker arm.