Control device for wheel loader
Provided is a control device for a wheel loader that is capable of improving the productivity of excavation work by reducing the work time required for the excavation work. A control device 120 is a control device for a wheel loader 1 that excavates a target by moving a vehicle body 2 forward with rotation of wheels 5 f, 5 r to plunge a bucket 3 into the target. The control device 120 moves the vehicle body 2 forward with the bucket 3 plunged into the target, and brakes the wheels 5 f, 5 r when a rotational speed of the wheels 5 f, 5 r exceeds a predetermined threshold BS.
1 . A control device for a wheel loader that excavates a target by moving a vehicle body forward with rotation of wheels to plunge a bucket into the target, wherein
the control device moves the vehicle body forward with the bucket plunged into the target, and brakes the wheels when a rotational speed of the wheels exceeds a predetermined threshold, such that a difference between a rotating amount of the wheels calculated from the rotational speed of the wheels and a moving amount of the wheels relative to a ground surface calculated based on a speed of the vehicle body before the bucket is plunged into the target and a deceleration of the vehicle body due to a reaction force from the target is within a range of a limit value in which the wheels do not slip.
2 . The control device for a wheel loader according to claim 1 , wherein
the control device performs automatic excavation processing in which traveling of the vehicle body and a posture of the bucket are controlled to automatically perform an excavation operation of the wheel loader, and
the excavation operation performed in the automatic excavation processing is an operation in which lifting of the bucket plunged into the target is started while moving the vehicle body forward, the bucket is rotated in a crowding direction to be brought into a loaded state after braking the wheels, and the lifting is stopped when the bucket reaches a predetermined height.
3 . The control device for a wheel loader according to claim 2 , comprising:
an enablement determination section that determines whether the automatic excavation processing is enabled; and
a start determination section that determines whether to start the automatic excavation processing,
wherein
the enablement determination section determines that the automatic excavation processing is enabled when the bucket is in an excavation posture within a predetermined range and the vehicle body is moving forward, and
the start determination section determines to start the automatic excavation processing when the enablement determination section determines that the automatic excavation processing is enabled, the bucket is in the excavation posture, and a pressure of a lift cylinder that performs the lifting changes to exceed a predetermined pressure.
4 . The control device for a wheel loader according to claim 2 , comprising:
an enablement determination section that determines whether the automatic excavation processing is enabled; and
a start determination section that determines whether to start the automatic excavation processing,
wherein
the enablement determination section determines that the automatic excavation processing is enabled when the bucket is in an excavation posture within a predetermined range and the vehicle body is moving forward, and
the start determination section determines to start the automatic excavation processing when the enablement determination section determines that the automatic excavation processing is enabled, the bucket is in the excavation posture, and a relative distance between the bucket and the target is equal to or smaller than a predetermined distance.
5 . The control device for a wheel loader according to claim 3 , wherein when the enablement determination section determines that the automatic excavation processing is enabled, the control device causes the wheel loader to perform a preparation operation for the automatic excavation processing, before the start determination section determines whether to start the automatic excavation processing.
6 . The control device for a wheel loader according to claim 1 , wherein the control device moves the vehicle body forward maintaining a vehicle speed of the vehicle body at a predetermined speed or greater before the bucket is plunged into the target.
7 . The control device for a wheel loader according to claim 1 , wherein when the rotational speed of the wheels exceeds the threshold, the control device brakes the wheels and reduces an output of a power source for the wheels.
8 . The control device for a wheel loader according to claim 1 , wherein when the rotational speed of the wheels exceeds the threshold, the control device brakes the wheels and cuts transmission of power from a power source for the wheels to the wheels.
9 . The control device for a wheel loader according to claim 4 , wherein when the enablement determination section determines that the automatic excavation processing is enabled, the control device causes the wheel loader to perform a preparation operation for the automatic excavation processing, before the start determination section determines whether to start the automatic excavation processing.