A flat storage facility includes a storage/retrieval device having a Y-direction moving member that is horizontally movable at a certain height above a storage item placement plane. A carriage is horizontally movable in an X direction on the Y-direction moving member, and a storage item gripping mechanism is provided in the carriage. The storage/retrieval device performs storage/retrieval on a storage item between the storage/retrieval device and respective storage item placement points set on the storage item placement plane. The storage item placement plane is divided into a plurality of unit sections at various heights with respect to a reference plane. When the storage/retrieval operation is performed with the storage/retrieval device, the lowering distance of the storage item gripping mechanism with respect to the carriage is adjusted according to the height of the unit section to which the storage item placement point of a storage/retrieval target belongs.

A method that involves determining the maximum operating speed of an electric motor under varying torque conditions, specifically at speeds surpassing its rated speed. Initially, the motor is operated at its highest speed across different torque values, establishing a data set of real measurement points. These points illustrate the relationship between the maximum motor speed and the applied torque. A coefficient (COF), ranging from 0 to 1 and dependent on motor characteristics, is selected. Two curves are then established: the first for lower maximum speeds, represented by

[00001]${}_{ref}=\frac{{\mathrm{COFP}}_{nom}}{T_{meas}},$

and the second for torques below a defined limit torque T.sub.lim expressed as

[00002]${}_{ref}=\frac{{\mathrm{COFP}}_{nom}}{f\left(T_{meas}\right)},$

where is a polynomial function derived from the measurement points. The appropriate curve is then used to ascertain the maximum motor speed for a given torque, based on whether the torque is greater or lesser than T.sub.lim.

Provided is a crane and a control method capable of preventing an irregular winding from being caused, without significant deterioration in work efficiency. The crane includes an allowable deceleration rate derivation unit and a winch control unit. The allowable deceleration rate derivation unit derives an allowable deceleration rate representing an allowable value of the deceleration rate of the winding of a suspension rope, from a measured load that is a suspension load measured by a load measurement device. The allowable deceleration rate derivation unit derives the allowable deceleration rate that is decreased with a decrease in the measured load. The winch control unit makes the winding of the suspension rope by a winch device decelerated at a deceleration rate limited within a range equal to or less than the allowable deceleration rate.

Provided is a crane and a control method capable of preventing an irregular winding from being caused, without significant deterioration in work efficiency. The crane includes an allowable deceleration rate derivation unit and a winch control unit. The allowable deceleration rate derivation unit derives an allowable deceleration rate representing an allowable value of the deceleration rate of the winding of a suspension rope, from a measured load that is a suspension load measured by a load measurement device. The allowable deceleration rate derivation unit derives the allowable deceleration rate that is decreased with a decrease in the measured load. The winch control unit makes the winding of the suspension rope by a winch device decelerated at a deceleration rate limited within a range equal to or less than the allowable deceleration rate.

A method for operating a conveying system is provided. An overhead hoist transport (OHT) vehicle is provided, wherein the OHT vehicle includes a gripping member configured to grip and hold a carrier, and a receiver configured to receive a signal. The signal is transmitted to the receiver of the OHT vehicle. The OHT vehicle is moved toward the carrier, and the carrier is gripped by the gripping member of the OHT vehicle. A lifting force is determined based on a weight of a carrier, a number of workpieces in the carrier, or a vertical distance between the OHT vehicle and the carrier, and the lifting force is applied to the carrier.

A method for operating a conveying system is provided. An overhead hoist transport (OHT) vehicle is provided, wherein the OHT vehicle includes a gripping member configured to grip and hold a carrier, and a receiver configured to receive a signal. The signal is transmitted to the receiver of the OHT vehicle. The OHT vehicle is moved toward the carrier, and the carrier is gripped by the gripping member of the OHT vehicle. A lifting force is determined based on a weight of a carrier, a number of workpieces in the carrier, or a vertical distance between the OHT vehicle and the carrier, and the lifting force is applied to the carrier.