EP4656809A1

EP4656809A1 - Method for managing bucket loading with bulk material of a work vehicle

Info

Publication number: EP4656809A1
Application number: EP25179355.0A
Authority: EP
Inventors: Giacomo Ichino; Andrea Gravili; Antonio Venezia; Ethan Bakken; Jonah Goetze
Original assignee: CNH Industrial Italia SpA; CNH Industrial America LLC
Current assignee: CNH Industrial Italia SpA; CNH Industrial America LLC
Priority date: 2024-05-31
Filing date: 2025-05-28
Publication date: 2025-12-03

Abstract

Management method of loading a bucket (BU) of a work vehicle (WL) with bulk material accumulated on the ground to form a pile (BK), the vehicle including an articulated arm (BO) to which the bucket is operationally hinged (BU) and a hydraulic circuit comprising a hydraulic pump (HP) arranged to be driven in rotation by a prime mover (E) and a first hydraulic actuator arranged to actuate the arm relative to the vehicle and a second hydraulic actuator arranged to actuate the bucket relative to the arm, the method, after a procedure for inserting the bucket into the pile, includes a breaking phase (Step 13) comprising: first partial and slow backward rotation of the bucket until reaching a predetermined cutting angle with respect to a support surface and contemporary; sudden lifting of the arm until reaching a predetermined height.

Description

Field of the invention

The present invention relates to the field of methods for automatic mission management of a work vehicle and in particular of a mission for loading a bucket with bulk material.

State of the art

Agricultural or work vehicles are equipped with an arm or lifter and a transmission which has the purpose of allowing the vehicle to be moved.
The transmission can be driven by a prime mover, usually on internal combustion engine, although in recent years vehicles have been developed in which the prime mover is defined by an electric motor.
As regards the motion of the arm, this includes at least two segments, in particular a first segment hinged to the vehicle chassis and a second segment hinged to the first segment. The second segment is represented by a bucket or shovel.
The activation of the different segments is achieved by double-action hydraulic actuators, often controlled by an open-centre hydraulic circuit.
The hydraulic circuit is powered by a dedicated hydraulic pump driven in rotation by the prime mover. The latter, therefore, can be both an internal combustion engine and an electric motor dedicated exclusively to drive the hydraulic pump dedicated to supply the arm and hydraulic users.
Despite the progressive electrification of work vehicles, it is preferred to keep the operation of users based on a hydraulic circuit, which is reliable and economical.
It is known that the same vehicle can be involved in several missions. Some missions involve cycling through a sequence of vehicle movements. Furthermore, in the same mission, similar movements, for example the forward movement of the vehicle, may require two different execution speeds. In fact, while a shovel loads the material with the bucket in the excavation or "dig" position, the forward movement of the vehicle requires low speed and high torque. On the contrary, when the vehicle needs to move from the loading location to the unloading location, the forward movement of the vehicle requires a relatively higher speed and lower driving torque.
The main missions for wheel loaders and excavators are:

Loading onto trucks: removing material or soil by throwing it directly into a truck through a bucket;
Hauling: transporting a load of material at various distances across a construction site using a bucket;
Material Pile: Defining a pile by means of the bucket, in a storage location for bulk materials, which is part of the bulk material handling process.

All the missions listed here involve loading the bucket with bulk material.
Subsequently, the material is moved to be loaded onto trucks, transported or accumulated.
The loading operation requires a certain commitment for the operator who must acquire some experience in coordinating the movements of the arm with the operation of the vehicle propulsion system.
Functions are known that allow automatic positioning of the bucket in a predetermined position, previously defined by the operator.
So rather than having to maneuver the arm every time to reach that position, the operator simply presses a button, so that a processing unit associated with the vehicle takes care of automatically moving the bucket to the aforementioned position in response to the pressure of this button.
These are simple operations, which exclusively concern a working organ, such as the arm. Complex operations within missions involve contextual control of the propulsion system and arm.
An ever-increasing automation of operations is required. Unless specifically excluded in the detailed description that follows, what is described in this chapter is to be considered as an integral part of the detailed description.

Summary of the invention

The aim of the present invention is to propose a method of automatic management of a loading mission of a bucket of a work vehicle.
Automatic management of the loading of a bucket must necessarily include a pile breaking phase after the bucket has penetrated the same pile.
It is worth highlighting that, for the present purpose, the way in which the bucket is inserted into the pile is not relevant, it may have been previously guided by the operator or by a more extensive automatic procedure.
The basic idea of the present invention is to perform a first partial and slow backward rotation of the bucket until reaching a predetermined cutting angle with respect to a support surface and at the same time perform a sudden lifting of the arm until it reaches a predetermined height. Here, the terms slow and sudden are related to each other. A slow movement means that it takes longer to complete than a sudden movement.
A slow movement, in terms of control of the hydraulic circuit, can mean an opening of the supply valve of the respective actuator by, for example, 30%. A sudden movement implies the opening of the valve in a range between 30% and 80%.
Any bucket has an approximately flat bottom surface. The angle of the bucket is therefore calculated between this lower surface and the ground. A cutting angle is generally between 30 and 80°.
The combined movement of the arm and the bucket, in the ways described, allows the pile to be cut quickly, limiting the driving torque necessary to carry out the operation. According to a further aspect of the invention, after cutting the pile, the procedure includes a second partial and sudden backward rotation of the bucket until it reaches a predetermined position spaced from a bucket actuation end of run.
Advantageously, this second rotation causes the portion of material balanced on the external edge of the bucket to fall into it, ensuring optimal filling.
According to a further preferred aspect of the invention, following the second backward rotation of the bucket the following steps are performed:

starting the vehicle in reverse and at the same time,
lowering of the arm to reach a predetermined position for moving a load along a path;
sudden rotation of the bucket backwards until it reaches the end of run in order to shake off the excess material.

Advantageously, the vehicle is prepared to transport the material along a path and the combination of the lowering movement of the arm and the rotation of the bucket to the end of its travel induces the excess material to detach, i.e. to fall, from the bucket. This helps keeping the work site clean.
An example of an automated bucket loading procedure is divided into

a first phase indicated as the "setup" phase which includes the following phases:
- Positioning of the bucket in a predetermined cutting position, generally indicated dig or excavation position, and at the same time,
- Forward starting of the vehicle to reach a first predetermined speed threshold, preferably without carrying out a feedback control on the vehicle speed;
  - . a second phase, following the first phase, indicated as "Approach": including
- monitoring of the vehicle's forward speed and the pressure of the arm actuation cylinder
- when the pressure increases and at the same time the speed is reduced, then
- detection of contact between the bucket and the pile.

The detection of the contact of the bucket with the pile can be determined when the pressure measured at the hydraulic actuator associated with the arm or bucket exceeds a first predetermined threshold, which can be absolute or percentage, and at the same time the speed of the vehicle reaches a second speed threshold lower than the first speed threshold.
Advantageously, the combined monitoring of speed and pressure makes the detection robust, also allowing you to calibrate the processing unit according to the different types of materials that form the pile and depending on the bucket insertion depth you want to achieve in the same phase of approach.
In the context of this description, prime mover can be understood as

an internal combustion engine that simultaneously drives the hydraulic pump and the transmission, regardless of whether this is hydrostatic or finite ratio, or
an electric motor served by the hydraulic pump which powers the hydraulic control circuit of the articulated arm. In this second case, a propulsion engine is provided which is evidently distinct and separate from the prime mover.

According to a preferred aspect of the invention, the first pressure threshold, measured at the actuator responsible for holding the arm and/or bucket, considered to determine the event of contact of the bucket with the pile is variable as a function of the speed of the vehicle.
When the prime mover is connected to both the hydraulic pump and the vehicle driveline, the contact of the bucket with the pile can be detected on the basis of the aforementioned pressure threshold and by monitoring the rotation speed of the prime mover.
This is advantageous as it allows the behaviour of the vehicle to be adapted to the resistance offered by the pile of material to the impact of the bucket. In fact, by increasing the speed of the vehicle, a more decisive insertion of the bucket into the pile is obtained, but at the same time the pressure threshold by which the insertion of the bucket into the pile is identified increases proportionally. This is useful when the pile includes compact materials such as clay or blocks of rock. On the contrary, an approach to a pile of light and/or soft material such as straw or sand requires a lower vehicle speed and consequently a lower pressure threshold for recognizing the contact of the bucket with the pile. Advantageously, the combination of vehicle pressure and speed monitoring allows filtering out false positives due to temporary contact of the bucket with rough ground.
According to a preferred aspect of the present invention, the procedure further comprises

. a third phase indicated as "penetration", subsequent to the second phase, in which the processing unit controls a flow of hydraulic oil towards the hydraulic actuator associated with the lifting of the arm during the advancement of the vehicle and an advancement of the vehicle caused by an increase in the driving torque of the propulsion engine, which in the case of a heat engine is obtained with an increase in its rotation speed; the resulting lifting of the arm may be modest or absent, however this causes an increase in the load on the front wheels with a consequent increase in the grip of the front wheels of the vehicle and at the same time, the increase in driving torque allowing the vehicle to advance against the resistance of the pile allowing the bucket to effectively penetrate the pile to fill adequately; this phase ends when an oil pressure measurement in the hydraulic actuator exceeds a second pressure threshold higher than the first pressure threshold or when a countdown ends, triggered when contact between the bucket and the pile is detected; the automatic penetration phase is caused in response to the event where the bucket hits the pile in dynamic conditions. Therefore, the penetration procedure is performed without interruption with respect to the detection of the contact of the bucket with the pile, exploiting the inertia of the moving vehicle which causes the impact of the bucket with the pile;
. a fourth phase, indicated as breakdown, coinciding with what is described above.

The cutting configuration of the bucket is such that the lower part of the bucket forms an angle between 30 and 80° with the ground.
Preferably, during the fourth phase, the processing unit is configured to readjust the rotation speed of the prime mover so as to ensure the necessary oil flow to the hydraulic actuators associated with the arm.
If the vehicle is equipped with a hydrostat controllable by the processing unit, inching is carried out in this phase, i.e. the propulsion is reduced to favour the flow of oil towards the hydraulic functions of actuation of the articulated arm. In case the inching function is not available in the vehicle, if the processing unit is configured to control the service brake, the latter is activated during the breaking phase to limit the vehicle advancement.
According to a preferred variant of the invention, after filling the bucket, the processing unit is configured to engage reverse gear and possibly deactivate the service brake and return the vehicle to the same point where the setup phase began.
The dependent claims describe preferred variants of the invention, forming an integral part of the present description.

Brief description of the figures

Further objects and advantages of the present invention will be clear from the following detailed description of an example of its implementation (and its variants) and from the attached drawings given purely for explanatory and non-limiting purposes, in which:

Fig. 1 shows a first exemplary flow diagram of the method of the present invention;
Fig. 2 shows a further exemplary flow diagram of an optional portion of the method object of the present invention:
- Fig. 3 shows a work vehicle in which the present invention is implemented.
  The same reference numbers and letters in the figures identify the same elements or components or functions;
- Fig. 4 shows in detail sub-steps, which form an essential part of the present invention, within a step of the flow diagram of Fig. 2;
- Fig. 5 shows in detail sub-steps within a step of the flow diagram in figure 2.

Evidently, the further steps in Fig. 2 are completely optional.
The same reference numbers and letters in the figures identify the same elements or components or functions.
It should also be noted that the terms "first", "second", "third", "higher", "lower" and the like may be used here to distinguish various elements. These terms do not imply a spatial, sequential, or hierarchical order for the modified elements unless specifically indicated or inferred from the text.
The elements and characteristics illustrated in the different preferred embodiments, including the drawings, can be combined with each other without departing from the scope of protection of the present application as described below.

Detailed description

The present invention concerns a method for automatic management of a bucket BU loading procedure and concerns an ECU processing unit associated with a work vehicle WL specifically configured to perform the management method. Fig. 1 shows an example of flowchart including essential and optional steps as described below.
At step 1, the operator, after placing the vehicle in front of a pile BK of bulk material accumulated on the ground, starts the automatic bucket filling procedure.
Optionally, in step 2 a series of conditions are checked before starting the procedure.

For example, the following table lists conditions to be verified in step 2:

C1	Parking brake	DEACTIVATED
C2	Hydraulic functions	ACTIVE
C3	Prime mover	OPERATING
C4	Arm control joystick	RELEASED
C5	Service brake	RELEASED
C6	Vehicle speed lower than a predetermined threshold	YES
C7	Position of the lower bucket at a predetermined height	YES
C8	Forward gear selection	YES

Condition C1 is intended to check whether the vehicle is not in parked condition.
Condition C2 is intended to check whether the hydraulic functions are active. In fact, the activation of the various hydraulic users on board is only possible when these are active to avoid, for example, during the movement of the vehicle that they are activated involuntarily.
Condition C3 is intended to check whether the prime mover is operational. For example, in the case of an internal combustion engine it must be on and at least in low idle, while, in the case of an electric prime mover, the relevant control inverter must be powered.
Condition C4 has the purpose of verifying whether the operator has released the joystick lever, otherwise, obviously, it is necessary to abort the procedure as the commands given manually take precedence over the autonomous control operated by the processing unit.
Condition C5 has the purpose of checking whether the operator has released the service brake pedal, as the setup phase involves the automatic start-up of the vehicle.
Another condition C6 concerns the speed of the vehicle, which must be lower than a predefined threshold that can be set, so that the vehicle does not impact against the pile of bulk material with an excessive and dangerous speed.
A further condition C7 concerns the position of the bucket, which must be adequate to start the loading operation, in the sense that it must not be excessively high. This condition is present for safety reasons, preventing it from being involuntarily activated when the high and full bucket is, generally, near a truck where emptying the bucket. Furthermore, with this condition it is possible to avoid the risk that the bucket does not have time to reach the correct dig position, pressing downward on the pile. This could cause the vehicle to rear up and overturn with serious risk for the operator.
The last condition, completely optional, concerns the selection of forward gear. Only if this is selected the vehicle can automatically start moving forward. According to another variant of the invention, the processing unit is configured to select forward gear autonomously.
It is worth highlighting that if the vehicle is moving forward then the setup, rather than starting the vehicle advancement, deals with regulating its speed.
If the conditions listed above are verified then in step 3 the first phase, setup, is performed, otherwise, in step 4, the interruption/abortion of the automatic procedure is signalled to the operator by indicating the unverified conditions and the system returns to step 1.
During the execution of the first phase, setup, in step 5 the correct achievement of the optimal position of the arm is monitored.
If during this monitoring step the pressure in the hydraulic cylinder supporting the arm exceeds a predetermined value or the optimal position is not reached promptly, i.e. within a predetermined time interval, then go to step 7, interrupting/aborting the procedure and reporting the interruption to the operator.
One of the main reasons why the optimal configuration of the arm is not reached or an abnormal pressure value is recorded is given by the fact that the bucket impacted the pile prematurely, i.e. before having reached the optimal position. This may essentially be due to the fact that the automated procedure was launched with the vehicle too close to the pile of material in relation to the time needed for the arm to reach the optimal loading position. This further check turns out to be advantageous because an increase in pressure in the actuator serving the arm is an indication of the fact that the bucket has prematurely impacted the pile. Therefore, interrupting the procedure prevents the vehicle from rearing up with serious danger for the operator.
Vice versa, if the correct position of the arm is reached without registering any abnormal value in the pressure, then go to step 6.
At step 6 the second phase, the approach, described above, is launched.
During the approach phase, the vehicle's forward speed is monitored and at the same time the pressure in the arm and/or bucket support cylinder. The advancement of the vehicle is controlled in an open chain by controlling the rotation speed of the prime mover if thermal or the torque supplied if it is an electric motor.
Then in step 8 a countdown starts.
When a reduction in the vehicle's forward speed and an increase in pressure in the bucket support cylinder is detected at the same time, before resetting the counter then go to step 9, otherwise, once the counter is reset, go to step 7.
Evidently, in step 9, the detection of contact between the bucket and the pile causes the counter to stop and reset to zero.
As previously described, the pressure threshold measured in the bucket support actuator and indicative of the contact of the bucket with the pile, is a function of the value of the automatic advancement speed of the vehicle performed in the setup itself.
An example of a work vehicle is shown in Fig. 3. This comprises a frame F to which an articulated arm BO, BU is hinged and comprises at least a first segment BO of elongated shape hinged to the frame at a first end and a second end, opposite the first, it supports a second segment which can be the BU bucket.
A first hydraulic actuator A1 is associated to the first segment, while a second hydraulic actuator A2 is associated to the bucket.
The actuator supporting the bucket can be understood as both the actuator supporting the first segment and the actuator supporting the bucket with respect to the first segment. Evidently, the arm can comprise further intermediate segments and further respective actuators.
The vehicle is equipped with an internal combustion or electric prime mover E. When the prime mover is an internal combustion engine it is defined as a prime mover and is generally connected to a transmission for propulsion of the vehicle and to a hydraulic pump to control the flow of oil which must be sent to the hydraulic circuit for actuating the articulated arm BO, BU. Conversely, when the propulsion engine is electric, then it is connected to the vehicle wheels directly or through a gearbox. In this second case, the hydraulic oil is pumped by an electric pump, i.e. a hydraulic pump driven by an electric motor, defined as a prime mover. Evidently, in the case of a full-electric vehicle, an increase in the torque and speed of the vehicle is achieved by controlling the electric propulsion motor, while an increase in hydraulic flow is obtained, independently, by controlling the electric pump or prime mover. These are evidently alternative solutions within the knowledge of the skilled person in the field.
With reference to Fig. 2, a further flow diagram is shown indicative of a further portion of the automatic bucket filling procedure. The steps indicated in Fig. 2 are a consequence of the detection in step 9 of the contact of the bucket with the pile.
At step 10 the penetration phase described above is started. The advancement of the vehicle, in the penetration phase, is obtained by appropriately regulating the driving torque of the propulsion engine.
During the penetration phase, step 11 is performed in which the pressure in the boom lifting cylinder is monitored and at the same time another countdown is launched.
When the pressure in the arm lifting cylinder exceeds a second pressure threshold higher than the first or the counter reaches zero then, at step 12, the penetration phase is interrupted, otherwise the cycle continues recursively on step 10.
After interrupting the penetration phase, the breaking phase begins at step 13.
After interrupting the penetration phase, the breaking phase begins at step 13.
The breaking phase is described with the help of the flow chart shown in figure 4.
It includes:

(Step 13.1) first partial and slow backward rotation of the bucket until reaching a predetermined cutting angle with respect to a support surface and simultaneously
(Step 13.2) sudden lifting of the arm until it reaches a predetermined height.

Preferably, it further includes, after the previous steps, (Step 13.3) a second partial and sudden backward rotation of the bucket until it reaches a predetermined position spaced from a bucket actuation limit switch.
At the same time as the breaking phase starts, step 14 of monitoring the arm configuration is started. This monitoring procedure cycles through step 13 until the arm and bucket are fully implemented as described above.
During steps 13.1 - 13.3, the vehicle can be stopped.
Preferably, during the breaking phase, the rotation speed of the prime mover is increased and the hydraulic actuators of the arm are controlled by signals such as to favor impulsive movements of the arm which facilitate the breaking of the material and a better distribution inside the bucket. According to a preferred aspect of the invention, the pressure thresholds of the arm and/or bucket support actuator, the forward speed of the vehicle, the rotation speeds of the prime mover, can be grouped into specific sets for each type of material that defines the pile to be recalled, in groups, in the pre-setting phase of this automated procedure. Thus, the operator can select, via a human/machine interface device, the type of material constituting the pile and in response to this choice, the processing unit selects the values relating to the aforementioned parameters.
Preferably, at the end of the breaking phase, step 15, reverse gear is automatically engaged and the vehicle is brought back to approximately the same position in which the present automatic bucket loading procedure was started. According to the flowchart of Figure 5, step 15 includes the following sub-steps:

(Step 15.1) starting the vehicle in reverse and at the same time:
(Step 15.2) lowering of the arm to reach a predetermined position position for handling a load along a path;
(Step 15.3) sudden rotation of the bucket backwards until it reaches the end stop in order to shake off the excess material.

The present invention can advantageously be carried out by means of a computer program which includes coding means for carrying out one or more steps of the method, when this program is executed on a computer. Therefore, it is understood that the scope of protection extends to said computer program and further to computer readable means comprising a recorded message, said computer readable means comprising program coding means for carrying out one or more steps of the method, when said program is executed on a computer.
Constructive variations to the non-limiting example described are possible, without departing from the scope of protection of the present invention, including all the equivalent embodiments for a person skilled in the art, to the content of the claims.
From the above description, the person skilled in the art is able to realize the object of the invention without introducing further construction details.

Claims

Management method of loading a bucket (BU) of a work vehicle (WL) with bulk material accumulated on the ground to form a pile (BK), the vehicle including an articulated arm (BO) to which the bucket (BU) is hinged and a hydraulic circuit including
- a hydraulic pump (HP) arranged to be driven in rotation by a prime mover (E) and

- a first hydraulic actuator arranged to actuate the arm with respect to the vehicle and

- a second hydraulic actuator arranged to actuate the bucket with respect to the arm,
the method, after a procedure for inserting the bucket into the pile, includes a breaking phase (Step 13) comprising:
- (Step 13.1) first partial and slow backward rotation of the bucket until reaching a predetermined cutting angle with respect to a support surface and simultaneously

- (Step 13.2) sudden lifting of the arm until it reaches a predetermined height.
Method according to claim 1, further comprising (Step 13.3) a second partial and sudden backward rotation of the bucket until reaching a predetermined position and spaced from a bucket actuation end of run.
Method according to claim 2, further comprising the following steps:
- (Step 15.1) starting the vehicle in reverse and at the same time:

- (Step 15.2) lowering of the arm to reach a predetermined position for handling a load along a path;

- (Step 15.3) sudden rotation of the bucket backwards until it reaches the end of run in order to shake off an excess material.
Method according to any one of the preceding claims, in which said phase of contact of the bucket with the pile is recognized, when, during monitoring of a vehicle advancement condition according to a first speed value, an increase of a pressure value is detected in a hydraulic actuator supporting the bucket, exceeding a first predetermined pressure threshold and at the same time at least a predetermined reduction in the advancement speed of the vehicle with respect to said first speed value.
Method according to claim 4, wherein said predetermined pressure threshold is a function of the first speed value.
Method according to claim 4 or 5, comprising a preliminary phase indicated as "setup" phase which includes the following phases:
- Positioning of the bucket in a predetermined position and at the same time,

- Starting the vehicle moving forward to reach said first speed value.
The method of claim 6, wherein the forward movement of the vehicle is controlled through the control of a propulsion prime mover (E).
Method according to any of the previous claims, further comprising the following steps resulting from the detection of the insertion of the bucket into the pile:
- sending a flow of hydraulic oil towards said actuator so that the bucket exerts a lifting force on the pile and at the same time

- advancement of the vehicle according to a first speed value.
Method according to claim 8, wherein prior to the step of inserting the bucket into the pile the method further comprises a step (9) of detecting a contact between the bucket and the pile when, during monitoring of an advancement condition of the vehicle according to a first speed value, an increase in a pressure value is detected in a hydraulic actuator supporting the bucket, exceeding a first predetermined pressure threshold and at the same time at least a predetermined reduction in the vehicle forward speed with respect to said first value of speed.
Method according to claim 9, wherein said predetermined pressure threshold is a function of the first speed value.
Method according to claim 9 or 10, said operating condition of forward movement of the vehicle is achieved after the simultaneous verification of the following conditions:
- (C1) a parking brake is deactivated;

- (C2) hydraulic functions are active;

- (C3) the prime mover and the propulsion engine are active;

- (C4) an articulated arm control human/machine interface device is released;

- (C5) a service brake is released.
Processing unit (ECU) of a work vehicle (WL), the alley comprising an arm (BO) and a bucket (BU) hinged to the arm and a hydraulic circuit comprising
- a hydraulic pump (HP) arranged to be driven in rotation by a prime mover (E) ed

- a propulsion engine,

- at least a first hydraulic actuator to control a movement of said arm with respect to the vehicle,

- at least a second hydraulic actuator to control a movement of the bucket relative to the arm,
the processing unit being configured to perform, following a procedure for inserting the bucket into a pile (BK) of bulk material accumulated on the ground,
- a first partial and slow backward rotation of the bucket until reaching a predetermined cutting angle with respect to a support surface and simultaneously

- a sudden lifting of the arm until it reaches a predetermined height.
A computer program comprising instructions for causing the processing unit of claim 11 to implement the method according to any of claims 1 - 10.
A computer readable medium having stored the program of claim 13.
Work vehicle (WL) comprising a bucket (BU) and propulsion means (E, W) and a processing unit according to claim 11, configured to automatically manage the loading of the bucket with loose material accumulated on the ground at form a pile (BK).