Device for controlling the transfer of a load suspended by cables from a carriage movable in translation in a lifting machine

Claim 1

A device for controlling the transfer of a load suspended by one or more cables from a carriage movable in translation in a lifting machine such as a travelling overhead crane or gantry crane comprising: control and dialogue means at the disposal of a machine operator; at least one horizontal travel motor associated with said carriage; means for sensing the suspension height, the sway angle and the angular speed of the load and the linear position of the carriage to provide respective signals L, θ, θ', X; and a speed control system which, according to signals received from said sensing means, procures movement of the carriage minimizing load sway, said speed control system comprising: a carriage position corrector for receiving the measured position signals X and a target position value X B and for delivering an offset value relative to target position ΔX weighted by a gain k 1 , a sway angle corrector for receiving the measured sway angle signal θ and a respective angular speed signal θ' and for assigning respective weighting values k 2 , k 3 to said sway angle signal and said angular speed signal, a computing unit for determining by real time interpolation the values of the gains k 1 , k 2 , k 3 according to the suspension height signal L, and a summing unit for summing the offset value, the weighted sway angle signal, and the weighted angular speed signal, for delivering a speed set point signal VC=k 1 ΔX+k 2 θ+k 3 θ' to a variable speed drive associated with a carriage displacement motor.

Claim 2

A device for controlling the transfer of a load suspended by one or more cables from a carriage movable in translation in a lifting machine such as a travelling overhead crane or gantry crane comprising: control and dialogue means at the disposal of a machine operator; at least one horizontal travel motor associated with said carriage; means for sensing the suspension height, the sway angle and the angular speed of the load and the linear position of the carriage to provide respective signals L, θ, θ', X; and a speed control system which, according to signals received from said sensing means, procures movement of the carriage minimizing load sway, said speed control system comprising: a carriage position corrector for receiving the measured position signals X and a target position value X B and for delivering an offset value relative to target position ΔX weighted by a gain k 1 , a sway angle corrector for receiving the measured sway angle signal θ and a respective angular speed signal θ' and for assigning respective weighting values k 2 , k 3 to said sway angle signal and said angular speed signal, a computing unit for determining by real time interpolation the values of the gains k 1 , k 2 , k 3 according to the suspension height signal L, and a summing unit for summing the offset value, the weighted sway angle signal, and the weighted angular speed signal, for delivering a speed set point signal VC=k 1 ΔX+k 2 θ+k 3 θ' to a variable speed drive associated with a carriage displacement motor.