Work machine and method for controlling work machine

A work machine comprising:

• a lower base;
• a slewing body slewably located on an upper part of the lower base and coupled with a boom that supports a rope that suspends a hoist load;
• a slewing motor that drives the slewing body;
• an obstacle detection device located in the slewing body and detecting an obstacle existing in a designated area set within a unique monitoring range;
• a slewing manipulation device including a slewing lever that receives a drive manipulation instructing the slewing motor to operate;
• and
• a controller that controls an operation of the slewing motor in response to the drive manipulation,
• wherein the controller is configured to execute first monitoring control and second monitoring control,
• in the first monitoring control, the controller is configured to set a first monitoring area that is set with respect to the slewing body as the designated area when the slewing motor is at a stop, when the obstacle is detected in the first monitoring area, the controller is configured to prohibit start of the slewing motor in response to the drive manipulation;
• and
• in the second monitoring control, the controller is configured to set one or more second monitoring areas that are set at places remoter from a slewing center of the slewing body than the first monitoring area as the designated area, when the obstacle is detected in the one or more second monitoring areas, the controller is configured to set an operation limitation of the slewing motor, and start, with the operation of the slewing motor limited, the slewing motor in response to the drive manipulation,
• wherein the one or more second monitoring areas include one second monitoring area that is set to correspond to a left slewing direction of the slewing body, and another second monitoring area that is set to correspond to a right slewing direction,
• the obstacle detection device is configured to detect the obstacle individually in the one second monitoring area and the other second monitoring area,
• the controller performs direction limiting processing,
• in the direction limiting process, when the obstacle is detected in the one second monitoring area, the controller is configured to prohibit the operation of the slewing motor that slews the slewing body in the left slewing direction, and allow the operation of the slewing motor that slews the slewing body in the right slewing direction, and
• in the direction limiting processing, when the obstacle is detected in the other second monitoring area, the controller is configured to prohibit the operation of the slewing motor that slews the slewing body in the right slewing direction, and allow the operation of the slewing motor that slews the slewing body in the left slewing direction.

A method for controlling a work machine, the work machine including:

• a lower base;
• a slewing body slewably located on an upper part of the lower base and coupled with a boom that supports a rope that suspends a hoist load;
• a slewing motor that drives the slewing body;
• an obstacle detection device located in the slewing body and detecting an obstacle existing in a designated area set within a unique monitoring range;
• a slewing manipulation device including a slewing lever that receives a drive manipulation instructing the slewing motor to operate;
• a controller that controls an operation of the slewing motor in response to the drive manipulation;
• a hook for hanging the hoist load, the hook being supported by the rope;
• and
• a winch configured to cause the hook to move up and down by winding or unwinding the rope,
• the work machine is a crane,
• the method comprising, as processes to be executed by the controller:
• a process of setting a first monitoring area that is set with respect to the slewing body as the designated area when the slewing motor is at a stop, when the obstacle is detected in the first monitoring area, prohibiting start of the slewing motor in response to the drive manipulation;
• and
• a process of setting a second monitoring area that is set at a place remoter from a slewing center of the slewing body than the first monitoring area as the designated area, when the obstacle is detected in the second monitoring area, setting operation limitation of the slewing motor, and starting, with an operation of the slewing motor limited, the slewing motor in response to the drive manipulation,
• wherein the first monitoring area is an area where the upper slewing body is configured to pass when the upper slewing body slews, and an area for detecting the obstacle that is configured to come into contact with the upper slewing body when the upper slewing body slews,
• wherein the second monitoring area is an area where the upper slewing body does not pass when the upper slewing body slews, and an area for detecting the obstacle existing at a position where the obstacle does not come into contact with the upper slewing body when the upper slewing body slews.