| 摘要 |
PROBLEM TO BE SOLVED: To prevent a torsional vibration of a hoist load in the case of turning it. SOLUTION: In an inertia moment arithmetic part 76, inertia moment of a coil lifter and a steel coil is obtained. In a rotational natural frequency arithmetic part 78, torsional rigidity of a vibration system, constituted by a wire and a pulley, is obtained, also from this torsional rigidity and the obtained inertia moment of the moment arithmetic part 76, a rotational natural frequency of the torsional vibration system is obtained. In a rotational speed pattern arithmetic part 82, based on a motion equation related to a given torsional vibration of the steel coil, the inertia moment and rotational natural frequency are used, the coil is turned to a target turn position in a shortest time, and a rotational speed pattern of the coil without turn vibrating in the target position is calculated, in a motor speed signal output part 84, a drive signal of a turn motor is output so as to realize the rotational speed pattern. |
