JPS6187033A - Power shovel control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a control device for a power shovel.

(Prior Art) As is well known, as shown in FIG. 7, a power excavator includes a bucket 1, an arm 2, a boom 3, a bucket cylinder 4, an arm cylinder 5, which moves each of these in an arc.
It has a boom cylinder 6. This bucket 1 moves by a combination of circular arc movements caused by the expansion and contraction of each of the cylinders. Therefore, in order to move the bucket 1 along a desired trajectory and attitude, it is essential to simultaneously control the expansion and contraction of each cylinder.

Therefore, in order to move the bucket 1 along the desired trajectory and attitude, the operator must operate the control levers corresponding to the bucket, arm, and boom simultaneously or alternately, which requires a long line of sight to operate. Ta.

In addition, when digging, unskilled workers may not orient the blade edge of the bucket in the direction of travel as shown in Figure 8 (a), or they may
), the bottom plate of the bucket was scraped and interfered with the excavation surface, causing an unnecessary increase in excavation resistance.

On the other hand, the bucket tip's transition trajectory (e.g., straight line, circular arc, etc.) and the bucket posture relative to these trajectories are set in advance, and the bucket, arm, and boom are automatically controlled so that the bucket tip moves along this trajectory. Various power shovel control devices have been devised to do this. However, this device has a problem in that it has a low degree of freedom because it is necessary to input the movement trajectory etc. in advance, and although it is effective for finishing work, it is not suitable for other excavation work.

(Problems to be Solved by the Invention) The control method for moving the bucket cutting edge in any direction has many degrees of freedom in the system even if the bucket cutting edge position or direction of movement is commanded, as shown in Figure 9. The length of each actuator with respect to the position of the cutting edge could not be specified 1-', but this was not done.

The present invention has been made in view of the above-mentioned circumstances, and provides a control device for a power sitabell that is capable of performing numerical exploration by determining the bucket posture based on a certain amount of outside thread and by only assigning the moving direction of the bucket cutting edge. The purpose is to provide.

(Means for Solving the Problems) According to the present invention, an operating lever for instructing the moving direction of the bucket cutting edge is provided, the trajectory of the bucket cutting edge is detected and memorized,
As long as the bucket bottom plate does not collide with the excavation surface that has already been excavated based on the memorized trajectory, and the rake angle between the bucket bottom plate and the moving direction instructed by the operating lever of the blade tip is small. The bucket attitude is determined so that the bucket attitude is determined, and the actuators of the boom, arm, and bucket of the power shovel are simultaneously controlled based on this bucket attitude and the moving direction of the bucket cutting edge instructed by the operating lever.

(Function) According to the present invention having the above configuration, by simply instructing the moving direction of the bucket cutting edge using the operating lever, the bucket cutting edge can be moved in the specified direction while maintaining the optimum bucket posture with less digging resistance.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the principle of the present invention will be explained with reference to FIG. Now, let us consider a case where the bucket 1 moves while drawing the bucket attitude and excavation trajectory P as shown in FIG.

' During this movement, the position of the bucket cutting edge Q is sequentially detected and the position is memorized, thereby storing the excavation trajectory P. Note that this storage amount is sufficient as long as it stores the trajectory from the current position of the cutting edge to the range where the bucket bottom plate 1a can collide.

On the other hand, an operating lever for instructing the moving direction of the bucket cutting edge Q is provided. This operating lever is a joystick operating lever 7 arranged in a cantilevered manner as shown in FIG. 3, and generates a signal instructing the moving direction of the bucket cutting edge Q depending on the operating direction of the operating lever.

If the angle (rake angle) between the direction R indicated by the operating lever 7 and the direction S of the bucket bottom plate 1a is α, then the rake angle α is determined as follows.

That is, the rake angle α is determined so that the bucket bottom plate 1a does not collide with the surface that has already been shaved, and the rake angle α is a predetermined small value. Of course, when the rake angle α is set to a predetermined small value and the bucket bottom plate 1a collides with the excavated surface, the rake angle α is set to the smallest value within the range that does not cause collision.

The rake angle α is determined by the memorized trajectory P, the direction S of the bucket bottom plate 1a, which can be determined from the moving direction R1 of the cutting edge Q instructed by the operating lever 7, and the rotation angles of the boom, arm, and bucket. determined by

This rake angle α and the moving direction R instructed by the operating lever 7
The attitude of the bucket 1 is uniquely determined by the following. Therefore, the boom, arm, and bucket actuators may be simultaneously controlled to move the bucket cutting edge Q in the direction instructed by the operating lever 7 while maintaining the bucket posture determined in this manner.

FIG. 1 is a block diagram showing an embodiment of a control device for a power shovel according to the present invention. This device includes an operating lever 7 (Fig. 3), a microcomputer 8 consisting of a central processing unit (CPU) 11, a storage device 12, a bucket angle sensor 31, an arm angle sensor 32, a boom angle sensor 33, and an engine rotation sensor. 34, a bucket hydraulic circuit 21, an arm hydraulic circuit 22, and a boom hydraulic circuit 23.

Each hydraulic circuit includes a variable capacity pump whose amount and direction of supply of pressure oil to the cylinder are controlled by a signal from the CPU II that commands expansion and contraction of the cylinder, and a variable capacity pump that controls the amount and supply direction of pressure oil to the cylinder by a signal from the CPU II that commands cylinder expansion and contraction, and a variable capacity pump that controls the pump and the cylinder by a cylinder operation command from the CPU 11. It has a solenoid valve etc. that opens and closes the hydraulic circuit with.

Next, the operation of this mounting will be explained with reference to the flowchart shown in FIG.

First, when the operator inputs an excavation start signal (step 101), the operator inputs the moving direction of the bucket cutting edge indicated by the operating lever 7 (step 102), and also inputs the bucket angle sensor 31, arm angle sensor 32, and boom angle sensor 33. Input the bucket angle θ, arm angle θ2, and boom angle θ3 shown in FIG.

Next, from the above angles 01, δ9, δ3, the respective lengths lo, 12.13 and package y of the bucket cylinder 4, arm cylinder 5, boom cylinder 6 and the current position Q of the cutting edge
Calculate and store these in the storage device (Step 1
03).

Now, as shown in FIG. 5, let us consider a case where the operator's grin indicates the direction of movement of the bucket in the direction of arrow P, and the bucket cutting edge is currently at position C. In addition, the fifth
In the figure, A is the previous cutting edge position, and B is the previous cutting edge target position. Here, point B is a point located at a distance from point A in the direction of arrow P.

In addition, this distance is determined by the maximum cutting edge speed Vmax determined by the power line and the interval Δt of the flow rate signal, using the following formula, L = Vmax
determined by

Furthermore, the reason why the current cutting edge position C is not located on AB is that the bucket does not move accurately in the designated direction due to excavation resistance or the like.

Now, the CPU II calculates the bucket movement distance 4fυ from the previous blade edge position A and the current blade edge position C (step 104). Then, the current desired position D and posture (Fig. 5) are determined from the previous cutting edge position A, previous cutting edge target position B, Q existing cutting edge position C, etc., and the error of the current position and posture with respect to the current desired position and posture is calculated by δ12. , find δ13.

, that is, the length of each cylinder at point A is llA, 12
A is 13A, and the length of each cylinder at point B is L12.
12B13B, the lengths l, D, 72D, and 13D of each cylinder at the current desired position and orientation are expressed as follows. -10,000, the current length of each cylinder is l + c12c
13C, the above errors δ11, δ12, δ13
is the following formula, These errors δ11, δ12, and δ13 are calculated by the calculator 13.
added to.

Next, the next target position E and target posture of the bucket cutting edge are calculated (step 106). Here, the target position E, as shown in FIG. As described above, the rake angle α of the bucket is determined to be a predetermined small value from the locus of the bucket cutting edge that has been cut, and the bucket bottom plate 1a is determined so as not to collide with the already excavated surface (trajectory).

Once the target position and orientation are calculated, the corresponding target length of each cylinder is also uniquely determined, and this target length, l,/,12,l; is calculated (step 1
07).

Next, the CPU II is in the most efficient operating state of the engine (a state in which it is rotating at the speed that outputs maximum horsepower).
maintaining each cylinder 4.5.6 to its respective target length 11', A! S! 1, K2, and K3 are calculated as proportionality constants that determine the flow rate of pressurized oil to be pumped to each cylinder 4.5.6 when the bucket 1 is expanded and contracted to ', 73', that is, when the bucket 1 is moved with maximum efficiency (step 108 ).

Furthermore, using 8, K2, and K as these proportionality constants,
Pressure oil flow rate Q1, Q2 force-fed to each cylinder 4.5.6
, Q, are calculated in degrees Celsius based on the following equations (step 109).

Qi = + (li'llr) K2~1-
KJδll... (:3) In equation (3), (c'
−l+ > indicates the deviation between the target position and attitude, the current position i, and the attitude, and δli indicates the deviation between the desired current position, attitude, current attachment, and attitude obtained in step 105, that is, the previous control error; Σδ11 indicates the cumulative error of the control error.

Note that Σδli is reset to Σδ1l=o when the operator changes the operating direction of the operating lever 7. The calculated values of 1, K2, and K8 are used to weight each term in equation (3), and are also used as gains for determining the total flow rate so that the engine speed is close to the maximum horsepower point. It is.

Next, the CPU II forms respective pressure oil flow signals corresponding to each pressure oil flow rate Q1, Q2, Q8 of each cylinder 4.5.6 shown in step 109, and sends these signals to the bucket hydraulic circuit 21. , the arm hydraulic circuit 22, and the boom hydraulic circuit 23 (step 110).

When each hydraulic circuit 21, 22, 23 receives each flow rate signal, it operates in response to each signal and pumps each pressure oil flow rate Q0, Q7, QB to each cylinder 4.5.6. Therefore, each cylinder 4.5.6 expands and contracts in response to each pressure oil flow rate Q1, Q2, Q, l (step 111). That is, the bucket 1 moves in the direction instructed by the operator with the rake angle α minimized in a posture that does not interfere with the excavated ground with the bottom plate 1a.

At this time, the engine speed changes depending on the load applied to the bucket throat 1. Therefore, engine rotation sensor 3
4 detects the engine rotation speed, and 1 is used as the proportionality constant to operate the engine in the most efficient condition again, K7
, K3 are recalculated (step 108). Thereafter, steps 109 to 111 are executed based on these proportionality constants 1, K2, and K8, thereby operating the engine most efficiently.

Then, when the bucket angle 01, arm angle e2, and boom angle θ8 change, the above process is executed again based on the changed angles and commands for the cutting edge movement direction.

In this way, the operator can move the bucket in the most efficient manner by simply operating the operating lever 7 in the desired direction, without causing the bucket bottom plate 1a to interfere with the excavation path, and with the rake angle of the bucket 1 minimized. With a good posture, you can move the bucket in the desired direction.

In this embodiment, a cantilever-shaped joystick is used as the operation lever, but the joystick is not limited to this, and any type of joystick may be used as long as it indicates the direction of movement of the bucket. Further, the rake angle α of the bucket is not limited to 0°, but may be appropriately set in a range of about 00 to 10°, although 0° provides the lowest digging resistance.

(Effects of the Invention) As explained above, according to the present invention, the bucket can be moved in the most efficient posture by simply instructing the moving direction of the bucket cutting edge using the operating bar, making the operation extremely simple. .

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a control device for a power shovel according to the present invention, FIG. 2 is a diagram showing the excavation locus of a bucket, etc. used to explain the present invention in principle, and FIG. 3 is a diagram similar to FIG. 1. A perspective view showing an example of the operating lever applied to the present invention shown in
FIG. 4 is a flowchart showing the control operation according to an embodiment of the present invention, FIG. 5 is a diagram used to explain the bucket control error and the next target position, etc., and FIG.
6 A structural diagram of a shovel, Figure 7 is a side view of a typical power shovel, Figure 8 is a diagram used to explain the defects in the excavation operation of a conventional power shovel bucket, and Figure 9 is a control of the power shovel. This is a diagram used to explain the above problem. 1...Bucket, 2...Arm, 3...Boom,
40.・Bucket cylinder, 5...arm cylinder,
6...Boom cylinder, 7...Operation lever, 8...
・Microcomputer, 9... Power shovel, 1
DESCRIPTION OF SYMBOLS 1... Central processing unit (CPU), 12... Storage device, 21... Bucket hydraulic circuit, 22... Arm hydraulic circuit, 23... Boom hydraulic circuit, 31... Bucket angle sensor, 32...7- angle a sensor, 33...
- Boom angle sensor, 34...engine rotation sensor. Figure 7 3,

Claims (1)

[Claims] A control lever for instructing the moving direction of the bucket cutting edge of a power shovel, a position detection means for detecting the position of the bucket cutting edge, a storage means for storing the trajectory of the bucket cutting edge based on the output of the position detection means, and a storage means for storing the trajectory of the bucket cutting edge by the output of the position detection means, Direction detection means detects based on each rotation angle of the boom, arm, and bucket of the power shovel, and the current position of the bucket blade edge and the direction of the bucket bottom plate detected by the position detection means and the direction detection means are stored by the storage means. Based on the trajectory of the bucket cutting edge, at least to the extent that the bucket bottom plate does not collide with the already excavated excavation surface,
rake angle setting means for successively setting a rake angle between the bucket bottom plate and the moving direction of the bucket cutting edge instructed by the operating lever to a minute angle, and the moving direction of the bucket cutting edge instructed by the operating lever and the rake angle setting means A power shovel comprising: a rake angle set by Control device.