Patent ID: 7936143

Claim:
A device for preventing sway of a suspended load for a trolley carriage equipped with a hoisting motor for hoisting a rope having one end to which a bucket is attached and a driving motor, the device comprising: a speed pattern creation circuit ( 11 ) for creating a speed command, a speed control device ( 14 ) for outputting a torque command based on the speed command, a torque command filter ( 16 ) for outputting a torque command by a first-order lag circuit by inputting the torque command, a load torque observer ( 4 ) for estimating and outputting a load torque on the trolley carriage by inputting the torque command which is an output of the speed control device ( 14 ), the device being configured to output a value obtained by adding a load torque estimation signal which is an output of the load torque observer ( 4 ) to an output of the torque command filter ( 16 ), characterized in that the device is further equipped with a high-pass filter ( 32 ) for outputting a signal T RFL HPF obtained by eliminating a fixed or a low frequency component corresponding to frictional resistance from the load torque estimation signal, and a sway angle calculator ( 33 ) for outputting a sway angle estimation calculated value θe obtained by multiplying a sway angle calculator factor by an output signal T RFL HPF from the high-pass filter ( 32 ), wherein a value obtained by subtracting a damping compensation signal N RFDP obtained by damping-compensating the sway angle estimation calculated value θe from a speed command created by the speed pattern creation circuit ( 11 ) is inputted to the speed control device ( 14 ).