Abstract
Crane arrangement (2) arranged in relation to a vehicle (4), the crane arrangement (2) comprising a movable arm (6) comprising a plurality of crane booms including a final crane boom with a crane boom tip (8); a crane manoeuvring unit (10) arranged to generate crane operation commands (12), such as commands for movements of the movable arm (6), based on received crane operation inputs (14) by an operator of the crane arrangement (2); a distance measurement arrangement (16) configured to measure and determine a straight line working distance (18) between said crane manoeuvring unit (10) and a predetermined location (20) at said movable arm (6), and to generate a distance signal (22) in dependence thereto, and a crane controller (24) arranged to monitor and control the movements of the movable arm (6) in response to crane operation commands (12) received from the crane manoeuvring unit (10) and of said distance signal (22) from the distance measurement arrangement (16). The crane controller (24) is configured to compare the working distance (18) to a first predetermined safety distance (34), and if said working distance (18) is shorter than said first predetermined safety distance (34), the crane controller (24) is arranged to stop crane movements. The manoeuvring unit (10) is configured to receive, from the operator, a crane operation input for continued operation, and if it is determined that said working distance (18) is shorter than said first predetermined safety distance (34) and if a crane operation input for continued operation is received by said manoeuvring unit (10), the crane controller (24) is arranged to activate a cautious operation mode that enables restricted movements of the movable arm (6) defined by a set of movement limitation rules.