JPS62220619A - Automatic excavator for loading machine - Google Patents

Abstract

PURPOSE:To enhance the efficiency of excavation by preventing excessive increasing of excavation resistance by a method in which only when the calculated vertical excavation resistance of a bucket is smaller than a set value, a boom is automatically controlled to perform upward rotation work. CONSTITUTION:In an automatic controller, an upper limit set value Rhu and a lower limit set value Rhd for horizontal excavation resistance and a set value Rvs for vertical resistance are set, and a loading machine is and excavation is made by a bucket 1. In this case, in the controller, the horizontal component Rh and vertical component Pv of excavation resistance to be applied to the bucket 1 are calculated. Only when Rhu>Rh>Rhd and Rv<Rvs, a boom 3 is put to upward rotating operation. Also, after Rv>Rvs results, the bucket 1 is put to tilting operation only until the end of period of a given excavation.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to loading machines such as wheel loaders, payloaders, and tractor excavators by controlling the work implement actuator with a microcomputer according to the load. This invention relates to an automatic excavation device for a loading machine that enables efficient excavation work without relying on technology.

[Conventional technology]

Loading machines such as wheel loaders, payloaders, and tractor excavators that have booms and buckets as work equipment actuators are compact, have a small turning radius, and are inexpensive to purchase.
It is used in a wide range of fields such as horticulture, landscaping, and snow removal work.

In this type of loading machine, the boom cylinder rotates the boom 1" downward, and the bucket cylinder tilts and dumps the bucket. These rotational movements of the boom and bucket move the earth and sand. Perform excavation and loading work such as

[Problem that the invention seeks to solve]

By the way, the hydraulic circuit of such a loading machine usually uses a tandem circuit that prioritizes the bucket, and each switching valve that drives the boom cylinder and bucket cylinder is controlled on and off with a fixed flow rate. It is not possible to operate the buckets at the same time, and it requires extremely high level of skill to manually switch each work equipment actuator for efficient excavation. There are many cases where the rear of the vehicle lifts due to excessive vertical resistance due to excessive thrusting in the horizontal direction, the bucket is covered too quickly and the excavated soil is insufficient, or the load is excessive and the tires slip, etc. There is a problem in that work efficiency varies greatly depending on driving technique.

This invention was made in view of the current situation (1).
1: In a loading machine equipped with a hydraulic circuit in which the main flow is fixed and can only be operated independently by one actuator, the flow is always maintained at the specified level without changing the configuration, regardless of the operator's skill. It is an object of the present invention to provide an automatic excavation device for a loading machine that can efficiently perform overhead excavation.

[Means for solving problems]

In order to solve this problem, in this invention, the bucket has a force of 1 vine that resists digging! [Means for sequentially calculating the components and vertical components; means for setting the 1-limit and lower limit set values of the water/P excavation resistance; and means for setting the vertical excavation resistance set values; Only when the calculated vertical excavation resistance is between the set value and the lower limit set value and is smaller than the set value of the vertical excavation resistance, the boom is rotated by -1 and the calculated vertical II'' ( Boo 3 = Switching control of each working machine valve that drives one and the bucket, respectively, in order to tilt the bucket only between the time when the excavation resistance becomes larger than the set value of the vertical excavation resistance and the end of the specified excavation. and control means for performing the same.

[Effect]

According to this configuration, a cycle operation of penetration travel-penetration travel/boom raising-penetration travel is performed according to the horizontal excavation resistance value, and then when the vertical excavation resistance value becomes greater than a predetermined set value, the bucket The tilt movement will begin.

〔Example〕

FIG. 2 shows an example of the external configuration of a wheel loader to which the present invention is applied. This wheel loader includes a bucket angle sensor 2 that detects the rotation angle θ1 of the bucket 1, and a bucket angle sensor 2 that detects the rotation angle θ2 of the boom 3. A boom angle sensor 4 detects the hydraulic pressure Pa of the pressure oil supplied to the boom cylinder 5 (not shown in FIG. 2), and a hydraulic pressure Pl of the pressure oil supplied to the bucket cylinder 7. Oil pressure sensor 8
(not shown in FIG. 2) is provided.

Detection values θ1, θ2, Pa, and P b of these bucket angle sensor 2, boom angle sensor 4, and oil pressure sensors 6 and 8
is input to the microcomputer 10 as shown in FIG. The microcomputer 10 sequentially calculates the horizontal component Rh and vertical component Rv of the excavation resistance applied to the bucket 1 during excavation using these detected values, and in the automatic excavation mode, the hydraulic circuit 20 is activated based on these calculated values Rh and Rv. The drive control is performed.

This hydraulic circuit 20 includes a boom control valve 21 that drives the boom cylinder 5, a bucket control valve 22 that drives the bucket cylinder 7, a tank 23,
Work equipment pump 24, pilot operating control/roll (POC) pump 25, boom control valve 2
A normal ON/OF valve consisting of a lift pilot valve 26 that performs switching control of the bucket control valve 22 and a tilt pilot valve 27 that performs switching control of the bucket control valve 22.
17 so as to add switching valves 30 and 40 operated by switching signals S1 and S2 from the microcomputer 10, respectively, to the F control type tandem circuit configuration. The switching valve 30 connects the lift pilot valve 26 to the upper lift spool 2 of the boom control valve 21.
8, and the switching signal S1
When is not input, the pilot valve 26 and the upper lift spool 28 are connected, but when the switching signal S1 is input, the POC pump 25 is connected to the -1- side lift spool 28.
Directly connected to. The switching valve 40 is disposed in the pilot pipe line from the tilt pilot valve 27 to the tilt side dump spool 29 of the bucket control valve 22, and when the switching signal S2 is not input, the pilot pipe 27 and the tilt side dump spool 29 are connected to each other. However, when the switching signal S2 is manually input, the POC pump 25 is directly connected to the tilt side dump spool 29. These switching signals S1 and S2 are input from the microcomputer 10 when the automatic excavation mode is designated by turning on the switch 11.

Here, before explaining the automatic excavation operation according to the configuration of this embodiment, let us explain the water/one-person resistance Rh according to FIGS. 3 and 4.
An example of a method for deriving vertical resistance Rv will be explained.

In this method, the bucket rotation (fJθ
1. Using the boom rotation angle θ2, the hydraulic pressure Pa of the pressure oil supplied to the boom cylinder 5, and the hydraulic pressure P I of the pressure oil supplied to the bucket cylinder 7, derive the horizontal resistance Rh and vertical resistance Rv using these detected values. do.

Now, if the cross-sectional areas of the boom cylinder 5 and bucket cylinder 7 are Sa and Sb, respectively, then each cylinder 5 and 7
The cylinder forces Fa and F b are Fa = Pa-8a
−(1) Fb=Pb −8b
...(2).

Here, it is assumed that the resistance application point PD (XD, YD) changes as shown in FIG. 4 in response to the same rotation of the bucket 1 (rotation angle θ1). In the graph shown in FIG. 4, the vertical axis is the distance DI7 between the tip point of the bottom plate of the bucket and the point of resistance PD, and the horizontal axis is the bucket rotation angle θ1, θh
(Fixed value) is the angle at which the side edge 1a of bucket 1 becomes horizontal, and Lc is the length of the side edge 1a.

Here, considering the X-Y coordinates centered on pin po, the coordinates of pin P1 before bucket 1 is rotated are (X+'
, Y+'), then the coordinates (XI, Yl) of Pl after 3 or 02 rotations of the boom are, and the illustrated distance between the bucket pin P1 and the tip point of the bucket bottom plate is pl, and the distance between the bucket bottom plate and the side edge 1a of the bucket is If the angle formed is ψ, the coordinates of pn (XD, Yl) after bucket 1 and boom 3 rotate θ1 and θ2, respectively, are
I) -X1+(1+, cosθ1- D L, cosψ
-(4) YD=Y+ 10Ω+-5inθ1-DI, -5
in ψ-= (5'), and based on the graph in FIG. 4, θ1. The coordinates of PD after θ2 rotation can be specified.

Now, let us define the dimensions shown in Figure 3 as Ll, L2°L3.
L4. L5 and considering the balance of moments around pin Po, Rv-XD+R11 YD-Fa-L4-Fl) ・
L5 = 0...
(6), and considering the balance of moments around pin P1, Rv・(XD+X1)−Rh・(Yl−Yl))−
Fb'・L3=0 (7). Also, Rh and Rv can be obtained by solving these equations ([i), (7), and (8).

Next, the automatic excavation operation according to the configuration of this embodiment will be explained with reference to the flowchart shown in FIG.

When carrying out automatic excavation, the operator turns on the automatic excavation mode switch 11, starts the engine, sets the gear to, for example, 1st gear, and drives the vehicle toward the top (step 100). In this initial excavation stage, horizontal plunge (sunset) excavation is performed in which the vehicle is driven with the boom 3 and bucket 1 stopped at their initial positions.

When the microcomputer 10 detects that the switch 11 is retracted, the microcomputer 10 detects each detection value θ1 of the bucket angle sensor 2, the boom angle sensor 4, the oil pressure sensor 6, and the oil pressure sensor 8.
゜θ2. Pa and pb are taken in, and using these detected values, the horizontal resistance Rh is calculated according to the method described above in FIGS. 3 and 4 (step 110). and,
The microcomputer 10 calculates the calculated horizontal resistance Rh.
is compared with a preset first limit set value Rhu of the horizontal resistance (step 120), and if Rh≦Rhu, the process returns to step 100 and the procedures of steps 100 and 110 are executed again. In other words, from the start of excavation, Rh -1-
Until the limit set value Rhu is exceeded, the boom 3 and the bucket 1 do not rotate and perform horizontal plunging excavation.

However, when Rh>Rbu, the microcomputer 10 outputs a switching signal S1 to switch the switching valve 30, sends the hydraulic pressure of the POC pump 25 to the "-" side spool 28 of the boom control valve 21, and sends the hydraulic pressure to the boom cylinder 5. By driving the boom 3 upward (step 130). Note that when the switching signal S1 is not manually input in the automatic excavation mode, the switching valve 30 is connected to the pilot valve 26 side, but since the lever of the pilot valve 26 is in the neutral position, the boom control valve 21 is connected to the pilot valve 26 side. No hydraulic pressure is sent to the spool 28 of the boom 3, and in this case the boom 3 is at rest.

Next, the microcomputer 10 again uses the sensors 2.4.
6 and 8 detected values θ1. θ2. Take in Pa and Ph h, and use these detected values to calculate the horizontal resistance Rh and vertical resistance Rv according to the formulas <6), (7), and (8) above (
Step 140). And microcomputer 10
Next, the calculated vertical resistance Rv is compared with a preset vertical resistance setting value Rvs (step 150). Note that the vertical resistance setting value Rvs is determined because when considering the moment around the front wheel due to the vertical resistance Rv, the length of the water component of the distance from the front wheel to the center of gravity of the bucket changes as the boom 3 rotates. , the height y of the bucket pin P1 (
6th depending on the bucket pin height (0 at the start of excavation)
Change as shown in the figure.

In addition, in FIG. 6, ya is a set value of the excavation end pin height.

As a result of the above comparison, if Rv is less than Rvs (Rv
s≧Rv), the microcomputer 10 then compares the calculated horizontal resistance Rh with a preset lower limit set value Rhd of the horizontal resistance (step 160), Rh>R
If it is HD, the switching signal S1 is output and the boom cylinder 5 is driven to the -L side in the same manner as described above, thereby raising the boom 3 by 1" (step 130). Thereafter, the results of each comparison in step 150 and step 160 are Rv
As long as ≦Rvs and Rh>Rhd, the microcomputer 10 outputs the switching signal S1 to cause the boom 3 to continue its upward movement.

However, if the result of the comparison in step 160 is Rb≦R
1+d, the microcomputer 10 stops outputting the switching signal S1 and stops the boom 3 at E'-stop+I-. Since the vehicle is always moving forward, if the raising of the boom 3 is temporarily stopped 1-, the horizontal resistance Rh caused by the load can be reduced.
As the amount of excavation increases, the shortage of excavation can be prevented. In this case, the procedure then returns to step 100.
Then, the calculated horizontal resistance Rh is the horizontal resistance.
The boom 3 remains stopped until the first limit set value Rhu is exceeded, and when Rh>Rhu, the boom 3 resumes its upward movement from the temporary stop position.

The above-mentioned upward drive of the boom 3 ends when Ry>Rvs as a result of the comparison in step 150 (
Step 180). The microcomputer 10 is Rv>
Rvs, the output of the switching signal S1 is stopped] Then, the lifting drive of the boom 3 is finished, and the switching signal S2 is outputted this time to switch the switching valve 40, thereby reducing the hydraulic pressure of the POC pump 25. The tilting operation of the bucket 1 is started by sending it to the tilt side spool 29 of the bucket control valve 22 and driving the bucket cylinder 7 to the tilt side (step 190). Thereafter, the microcomputer 10 continues to output the above-mentioned 1; (Step 200). In addition, as a detection method at the end of excavation, sand ridge 1a of bucket 1
There are a method of determining the end of excavation when the bucket pin P1 becomes horizontal, a method of determining the end of excavation when the bucket pin P1 reaches a predetermined height above the ground, and a method of detecting the stroke end of the bucket sill.

FIG. 7 shows an example of the trajectory of the bucket according to this embodiment, and state (1) is a state where only the digging operation is performed at the start stage of excavation (steps 100, 110, 120 in FIG. 5).
), and state (I[) indicates penetration travel with the boom being driven 1° up.130, 140, 150,
Steps 170, 100, 110), state (III) indicates penetration travel with the boom temporarily stopped;
120), state (IV) indicates penetration travel with the boom being driven upward, and steps 130, 140.
150, 160), state (V) indicates penetration travel in a state where the bucket is tilt-driven.

According to this embodiment, the upper and lower limit set values Rhu and R1 are set for the horizontal resistance, and the set value RVS as shown in FIG. 6 is set for the vertical resistance, and the sequentially detected horizontal resistance Rh and the above-mentioned ” Penetration travel according to the comparison results with the 1st limit and lower limit setting values - Penetration travel / Boom raising -
In addition to performing cycle control of penetration travel, automatic excavation is performed such that when the detected value Rv of vertical resistance exceeds the set value RVS, the -1-rise of the boom is completed and the tilting movement of the bucket is started. As a result, there is no problem such as tire slippage or lack of nails during excavation.
A predetermined amount of soil can be automatically excavated at any time. Also,
According to this automatic excavation control, the actuator being operated is always either the bucket cylinder or the boom cylinder, so the current mainstream model is equipped with a hydraulic circuit with a tandem circuit configuration with a fixed flow rate. It is possible to realize an automatic excavation machine that can perform efficient excavation by only partially changing the configuration of the loading machine.

In the embodiment described in -1-, a configuration may be adopted in which the horizontal resistance upper and lower limit set values Rhu and Rhd and the vertical resistance set value Rv can be arbitrarily changed each time one excavation is completed.

Furthermore, the calculation method for determining the horizontal resistance Rh and the vertical resistance Rv is not limited to the method explained using FIGS. 3 and 4. Rh and Rv may be determined based on the detected value and the force balance between the horizontal and vertical resistances Rh and Rv.

Furthermore, the loading machine to which the present invention is applied is not limited to wheel loaders, but may also include payloaders, tractor excavators, etc.
It is applicable to all machines that have a boom and a bucket as work equipment actuators.

〔Effect of the invention〕

As explained above, according to the present invention, (1) I%
Since the boom drive and bucket drive are switched and controlled according to the excavation resistance, the excavation resistance does not become excessive and this prevents tire slip.
(1) It is possible to extend the life of the tire and greatly improve the excavation efficiency. (2) It is possible to always excavate a uniform amount of soil regardless of the operator's experience and skill. 3) Since the actuator that is being operated is always either the bucket or the boom, it has excellent effects such as being suitable for application to loading machines with a tandem circuit configuration, which is the mainstream at present.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of the overall control configuration of a device according to an embodiment of the present invention, FIG. 2 is a side view showing the external configuration of a wheel loader and an example of arrangement of each sensor, and FIG. 11!7 A diagram for explaining a calculation example for determining the resistances Rh and Rv. Fig. 4 is a graph showing an example of a set movement locus of the resistance application point used in the calculation example. Fig. 5 is the same example. FIG. 6 is a flowchart showing a specific example of the operation of the device, FIG. 6 is a graph showing the relationship between the vertical resistance setting value Rvs and the bucket height y, and FIG. 7 is a diagram showing an example of the bucket trajectory by the device of this embodiment. 1...Bucket!・, 2... Bucket angle sensor, 3.
... Boom, 4... Boom angle sensor, 5... Boom cylinder, 6.8... Oil pressure sensor, 7... Bucket cylinder, 10... Microcomputer, 20...
・Hydraulic circuit, 21...Boom control valve, 2
2... Bucket control valve, 23... Tank, 24... Work equipment pump, 25... POC pump, 26... Lift pilot valve, 27... Tilt pilot valve, 28.29 ...Spool, 30.4
0...Switching valve. Figure 3 θh θl

Claims (1)

[Claims] In an automatic excavation device for a loading machine that performs excavation by automatically driving and controlling the boom and bucket while the loading machine is running, means for sequentially calculating a horizontal component and a vertical component; means for setting upper and lower limit setting values of the horizontal excavation resistance and vertical excavation resistance setting values; and means for setting the horizontal excavation resistance so calculated as the upper and lower limit setting values. The boom is raised and rotated only when the calculated vertical excavation resistance is smaller than the set value of the same vertical excavation resistance, and the calculated vertical excavation resistance is larger than the set value of the same vertical excavation resistance. automatic excavation of a loading machine, comprising a switching control means for controlling the switching of each working machine valve that drives the boom and the bucket, respectively, so that the bucket is tilted only between the time when the excavation is completed and the end of a predetermined excavation. Device.