Crane control method and crane

A crane control method for horizontally transferring a suspended load, using a crane,

• the crane including:
• a derricking body;
• a derricking rope connected to the derricking body;
• a derricking winch that winds up the derricking rope or unwinds the derricking rope to change an angle of the derricking body;
• an angle detector that detects an angle of the derricking body;
• a hook for suspending the suspended load therefrom;
• a hoisting rope connected to the hook, the hoisting rope drooping from a front end of the derricking body;
• and
• a hoisting winch that winds up the hoisting rope or unwinds the hoisting rope to change a length of a part of the hoisting rope that droops from the front end of the derricking body,
• a controller capable of controlling the derricking winch and the hoisting winch, the controller including:
• a derricking operation unit that receives an operation that instructs operation of the derricking winch;
• a correction operation unit that receives a correction operation of specifying a specified value for correcting an operation speed of the hoisting winch;
• and
• a storage that is a nonvolatile storage and that stores at least one piece of registered correction data including a plurality of registered values associated with a plurality of section angle ranges, the plurality of registered values each representing a degree of correction for adjusting an operation speed of the hoisting winch and the plurality of section angle ranges being set by dividing a movable range of the derricking body into different sections,
• the crane control method comprising:
• executing, by the controller, parallel winch control of causing the derricking winch and the hoisting winch to operate when an operation on the derricking operation unit is detected in a situation where a control mode for horizontal transfer of the suspended load is selected;
• and
• executing, by the controller, a correction process when the correction operation is detected in a situation where the parallel winch control is executed,
• wherein the parallel winch control includes:
• causing, by the controller, the derricking winch to operate at a speed corresponding to an amount of operation on the derricking operation unit;
• acquiring, by the controller, a derricking angle that is a detection angle detected by the angle detector and specifying a reference target value corresponding to the derricking angle, from among the plurality of registered values;
• deriving, by the controller, a reference speed ratio according to the derricking angle, the reference speed ratio representing a ratio of an operation speed of the hoisting winch to an operation speed of the derricking winch;
• deriving, by the controller, an applied speed ratio by correcting the reference speed ratio with the reference target value;
• and
• causing, by the controller, the hoisting winch to operate at a speed corresponding to an operation speed of the derricking winch and to the applied speed ratio, and
• the correction process includes:
• executing, by the controller, a speed correction process in a correction period corresponding to a point of time at which the correction operation is detected, the speed correction process being a process of correcting the reference target value used for deriving an operation speed of the hoisting winch in the parallel winch control, in accordance with the specified value specified by the correction operation;
• and
• executing, by the controller, a data updating process of updating data of the reference target value, the data corresponding to the correction period in the storage, to data corrected with the specified value specified by the correction operation.