Loader control system and loader control method

1. A loader control system, comprising:

a boom position calculation unit configured to calculate a position of a boom rotatably supported by a vehicle body of a loader;

a bucket attitude calculation unit configured to calculate an attitude of a bucket rotatably supported by the boom;

a determination unit configured to determine whether or not the attitude satisfies a predetermined condition on a basis of the attitude and a reference attitude of the bucket in dumping movement; and

a work machine control unit configured to cause the bucket to carry out the dumping movement, and output a control signal to cause the boom to carry out lifting movement when the attitude is determined to satisfy the predetermined condition.

2. The loader control system according to claim 1 , wherein when the attitude is determined not to satisfy the predetermined condition, the work machine control unit outputs a control signal to maintain the position of the boom during the dumping movement of the bucket.

3. The loader control system according to claim 1 , wherein

the attitude includes a detected angle which is an angle calculated on a basis of detection data of the attitude of the bucket,

the reference attitude includes a reference angle which is an angle of reference of the bucket,

after placing the boom at an unloading operation start position, the work machine control unit starts the dumping movement of the bucket,

within a first turning zone of the bucket in which the detected angle is larger than the reference angle, the bucket carries out the dumping movement with the boom maintained at the unloading operation start position, and

within a second turning zone of the bucket in which the detected angle is not larger than the reference angle, the bucket carries out the dumping movement while the boom carries out lifting movement.

4. The loader control system according to claim 1 , further comprising:

a number-of-unloading counting unit configured to count number of times unloading operation is carried out with respect to one object into which soil is to be unloaded, the unloading operation unloading soil from the bucket into the object, wherein

the work machine control unit changes an unloading operation start position of the boom on a basis of the number of times of unloading.

5. The loader control system according to claim 4 , wherein the work machine control unit sets the unloading operation start position of the boom to be higher as the number of times of unloading is larger.

6. The loader control system according to claim 1 , further comprising:

a load sensing device configured to detect whether the bucket is in an unloaded state or a loaded state; and

a start signal acquisition unit configured to acquire a start signal instructing to start control of the dumping movement, the start signal being generated by a manipulation device, wherein

the work machine control unit starts output of the control signal when the start signal is acquired, when the load sensing device has detected that the bucket is in the loaded state, and when a detected angle of the boom is determined to be not smaller than a threshold.

7. The loader control system according to according to claim 1 , wherein the work machine control unit cancels output of the control signal when the load sensing device has detected that the bucket is in an unloaded state, and when the loader is determined to be moving rearward.

8. A loader control method comprising:

calculating an attitude of a bucket rotatably supported by a boom in dumping movement of the bucket; and

causing the boom to carry out lifting movement when the attitude satisfies a predetermined condition.

9. The loader control method according to claim 8 , further comprising:

counting number of times unloading operation is carried out with respect to one object into which soil is to be unloaded, the unloading operation unloading soil from the bucket into the object; and

changing an unloading operation start position of the boom on a basis of the number of times of unloading.