JPH0663247B2 - Control device for work equipment in power shovel - Google Patents

Description

The present invention relates to a control device for a work machine in a power shovel.

[Prior Art] Conventionally, in order to improve the operability of a power shovel, a speed vector of an arm tip point is commanded by an operation lever, and a boom for moving the arm tip in the direction and speed of the commanded speed vector. The rotation speed and the arm rotation speed are calculated, and the bucket rotation speed for keeping the bucket ground angle constant is calculated regardless of these rotation speeds. The boom, arm, and bucket are automatically calculated at these rotation speeds. Some have been designed for simultaneous control (Japanese Patent Laid-Open No. 55-
30038).

According to such a conventional control device, since the bucket tilt angle control with the bucket ground angle θ is constant is performed for the velocity vector control of the arm tip point, linear excavation is very easy to perform as shown in FIG. 4 (a).

[Problems to be Solved by the Invention] However, when performing horizontal excavation as an actual work, the initial angle of the bucket is set near the cylinder stroke end in order to make the reach as shown by the solid line in FIG. 4 (b). Often. If horizontal excavation is performed at a speed V _X from this state, the bucket reaches the stroke end immediately because of constant bucket-to-ground angle control, and thereafter bucket control cannot be performed.

Therefore, there is a problem that the excavation locus at the tip of the bucket goes deeper than the target locus as shown by a broken line in a circular arc.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for a work machine in a power shovel that can move the bucket blade tip point in a target direction even when the bucket reaches the stroke end.

[Means for Solving the Problems] According to the present invention, a velocity vector setting means for setting a velocity vector to move the bucket blade tip point in the plane including the boom, the arm and the bucket as a coordinate plane, Angle detecting means for detecting the boom angle and arm angle, a stroke end detecting means for detecting the stroke end of the bucket, a bucket based on the speed vector set by the speed vector setting means and the detected angle of the angle detecting means. First to obtain the boom rotation speed and the arm rotation speed, respectively, so that the speed vector at the rotation point coincides with the speed vector set above.
Of the speed vector set by the speed vector setting means and the angle detection means of the speed vector setting means, the second calculation means for obtaining the bucket rotation speed or the bucket rotation angle so that the ground angle of the bucket becomes constant. Under the condition that the bucket is fixed at the stroke end based on the detected angle, the boom rotation speed and the arm rotation speed are calculated so that the speed vector of the bucket blade tip point matches the speed vector set above. When the stroke end of the bucket is not detected by the calculation means of No. 3 and the stroke end detection means, the calculation results of the first and second calculation means are output, and when the stroke end of the bucket is detected, the third calculation means is output. Based on the switching means for outputting the calculation result of the calculating means, and the calculation result added from the switching means Consists flow control means for controlling the pressure oil supply flow to the corresponding working machine cylinder is Re respectively.

[Operation] That is, when the bucket is within the movable range, the boom and the arm are controlled so that the arm tip point moves according to the commanded velocity vector, and the bucket is controlled so that the bucket ground angle becomes constant. , When the bucket reaches the stroke end and the constant ground angle control becomes ineffective, it is assumed that the bucket is fixed to the arm tip point at the stroke end, and the bucket blade point moves so as to move according to the commanded velocity vector. ， It is designed to control the arm.

EXAMPLES The present invention will be described in detail below with reference to the accompanying drawings.

Fig. 2 shows boom of shovel 1, arm 2, bucket 3
Each of the working machines is schematically shown. A plane including each working machine is set as an XY coordinate plane, and the rotation A of the boom 1 is set as a coordinate origin. Here, the angle α between the Y axis and the boom 1 is the boom angle, the angle β between the boom 1 and the arm 2 is the arm angle, the angle γ between the arm 2 and the bucket 3 is the bucket angle, and C is the arm tip point. , D are bucket blade tip points. It should be noted that the drawing shows the case where the bucket 3 reaches the stroke end and the bucket angle γ is γend.

First, control for moving the arm tip point according to the commanded velocity vector and control for keeping the bucket ground angle constant will be described.

Now, the coordinates (X _C , Y _C ) of the arm tip point C are as follows: Given in. Here, l ₁ and l ₂ indicate the boom length (line segment AB) and the arm length (line segment BC), respectively.

Next, the coordinates (X _C , Y _C ) of the above equation (1) are time-differentiated, and the velocity components ( _{C 1} , _{C 2} ) in the X-axis and Y-axis directions are obtained as follows.

Therefore, in order to control the speed of the arm tip point C to the speed ( _{C 1} , _C 2), the boom 1 and the arm 2 are rotated at the boom rotation speed and the arm rotation speed that satisfy the above expression (2). Dynamic speed control may be performed. Solving the equation (2) for the boom rotation speed and the arm rotation speed, the following equation is obtained.

Further, in order to control the bucket ground angle to be constant, a value obtained by inverting the sign of the sum of the boom rotation speed and the arm rotation speed obtained by the above equation (3)-
(+) Or a value obtained by inverting the sign of the sum of the boom rotation speed and the arm rotation speed of the actual machine may be given as the rotation speed command of the bucket 3.

When the bucket ground angle is made constant in this way, the movement locus of the tip point and the movement locus of the bucket blade tip point become parallel as shown in FIG. 4 (a), and the arm tip point moves in accordance with the commanded velocity vector. Then, the bucket blade tip also moves according to the commanded velocity vector.

Next, a description will be given of control for moving the bucket blade tip point according to the commanded velocity vector when the bucket reaches the stroke end and constant ground angle control is no longer effective.

In this case, it is assumed that the bucket 3 is fixed to the arm tip point at the stroke end. At this time, the bucket edge point D
The coordinates (X _D , Y _D ) of Given in. Where l ₃ is the bucket length (line segment CD),
γend indicates the bucket angle when the bucket is at the stroke end (see FIG. 2).

When the above equation (4) is differentiated with respect to time and the boom rotation speed and the arm rotation speed are summarized, Becomes

Instead of the above equation (5), the length of the boom tip point B and the bucket blade tip point D when the bucket 3 is at the stroke end is set to l ₂ ′ as shown in FIG. Assuming that the angle formed by the line segments BC and BD is Δβ, in the formula (3), l _{2 is set} to ₁₂ ′ and β is set to (β−Δβ).
Replaced by May be

Therefore, if the bucket 3 is within the movable range, the boom 1 and the arm 2 are controlled based on the boom rotation speed and the arm rotation speed according to the expression (3), and the bucket 3 has a constant bucket ground angle. When the bucket 3 reaches the stroke end, the boom 1 and the arm 2 are controlled based on the boom rotation speed and the arm rotation speed according to the formula (5) or the formula (6).

FIG. 1 is a block diagram showing an embodiment of a control device for controlling a working machine of a power shovel based on the above principle. In the figure, an operating lever 10 is a cantilever operating lever arranged at an appropriate position in the driver's seat, and commands the traveling direction of the bucket blade tip point by its operating direction, and the bucket blade tip point by the operation amount. Command the speed of progress. The traveling direction and traveling speed of the bucket blade tip point set by the operation lever 10, that is, each velocity component ( _D ^ref , _D of the velocity vector of the bucket blade tip point).
^The signal indicating ^ref ) is applied to the coordinate conversion circuit 11.

Further, the operation lever 10 can rotate about the lever shaft, and the bucket rotation speed ^ref
Can be specified. In addition, when the operation lever 10 is not operated, this operation lever takes the neutral position,
All of the above speed commands are zero.

Signals indicating the boom angle α, the arm angle β and the bucket angle γ of the actual machine are added to the other inputs of the coordinate conversion circuit 11 from the boom angle detector 12, the arm angle detector 13 and the bucket angle detector 14, respectively. There is. The coordinate conversion circuit 11 includes a stroke end detection circuit that detects whether or not the bucket 3 has reached the stroke end from the signal indicating the input bucket angle γ, and this detection circuit determines that the bucket 3 has not reached the stroke end. Then, based on the signal indicating each velocity component ( _D ^ref , _D ^ref ) of the input velocity vector and the signal indicating the boom angle α and the arm angle β, the bucket blade tip point D (arm tip point C) is set to the above velocity. Boom rotation speed required to move in vector
^ref and arm rotation speed ^ref are calculated ((3))
formula).

The boom rotation speed ^ref thus calculated is added to the addition point 15 as a target value of the rotation speed of the boom 1. Additional points
A feedback amount indicating the actual rotation speed of the boom 1 is added to the other input of 15 from the boom rotation speed calculation circuit 16. The boom rotation speed calculation circuit 16 calculates the boom rotation speed by performing a difference calculation of the boom angle α applied from the boom angle detector 12 per unit time.

At the addition point 15, a deviation with respect to the target rotation speed is taken, and this deviation signal indicates a compensator 17 that cancels this deviation quickly and performs proportional / integral / derivative compensation so that stable control is performed. Flow rate control valve 18 via

The flow rate control valve 18 supplies the boom cylinder 4 with pressure oil having a flow rate according to the input signal. As a result, the boom 1 is rotationally controlled so as to have the target rotational speed ^ref .

As for the arm 2, similarly to the above, a deviation between the target rotation speed ^ref and the actual arm rotation speed added from the arm rotation speed calculation circuit 20 is obtained at the addition point 19, and this deviation is passed through the compensator 21. Is added to the flow rate control valve 22, and the required flow rate of pressure oil is supplied to the arm cylinder 5 by the flow rate control valve 22.

As a result, the arm tip point C moves according to the velocity vector commanded by the operating lever 10.

Further, signals indicating the boom rotation speed and the arm rotation speed obtained by the boom rotation speed calculation circuit 16 and the arm rotation speed calculation circuit 20 are added at an addition point 23, and the added value is a negative value of the addition point 24. Added to input.

A signal indicating the bucket rotation speed ^ref is added to the positive input of the addition point 24 from the operation lever 10, and the addition point 24 adds these inputs and adds them to the adder 25. At the addition point 25, a deviation between the target rotation speed { ^ref − (+)} and the actual bucket rotation speed added from the bucket rotation speed calculation circuit 26 is taken, and this deviation is controlled by the compensator 27. In addition to the valve 28, the flow control valve 28 supplies the required pressure oil to the bucket cylinder 6.

Therefore, the bucket rotation speed depends on the operating lever 10.
^{When ref} = 0 is commanded, the bucket 3 rotates at the speed − (
Therefore, the bucket 3 is controlled so as to maintain the initial posture, that is, the bucket ground angle is constant regardless of the rotation of the boom 1 and the arm 2.

On the other hand, when the bucket 3 reaches the stroke end and this is detected by the stroke end detection circuit in the coordinate conversion circuit 11, the coordinate conversion circuit 11 determines that the bucket blade tip point is on condition that the bucket 3 is fixed at the stroke end. The boom rotation speed ^ref and the arm rotation speed ^ref are ^calculated so that the speed vector of D matches the speed vector commanded by the operating lever 10 (Equation (5) or (6)), and The signal indicating the dynamic speed is switched to the signal indicating the rotational speed, which is the target value, and is output.

As a result, the bucket blade tip point D moves according to the velocity vector commanded by the operation lever 10.

The bucket rotation speed ^ref =
When 0 is commanded, the bucket 3 is given a target speed − (+), which is a value obtained by inverting the sign of the added value of the boom rotation speed and the arm rotation speed of the actual machine.
The bucket 3 has already reached the stroke end, and the bucket 3 does not rotate depending on the target speed. Also,
In place of the above embodiment, when the bucket angle γ is at the angle γend indicating the stroke end, the speed −
The signal indicating (+) may not be added.

Next, another embodiment of the present invention will be described.

In this embodiment, when the bucket 3 is within the movable range, the velocity vector ( _D ^ref , _D ^ref ) of the bucket blade point and the bucket absolute angular velocity are given by the operating lever, and the boom 1, the arm 2, and the bucket 3 are exactly as they are. Even if a command is given during work, the bucket blade point moves on a straight line. In addition, a mode for finishing the slope angle can be added by switching a switch.

Now, when the bucket 3 is within the movable range, the conversion formula for moving the bucket blade point according to the commanded velocity vector is as follows, even if the bucket absolute angular velocity ≠ 0 is given during work. Becomes Here, when the bucket cylinder reaches the stroke end (γ _max or γ _min ) during control, the bucket control becomes ineffective. Therefore, from the control based on the above equation (7), the above equation (5) is used. Alternatively, the control is switched to the control based on the expression (6), and the velocity vector control of the bucket blade tip point is performed only by the boom 1 and the arm 2.

In FIG. 3, the operating lever 30 is the operating lever 10 of FIG.
In the same manner as the above, a signal indicating each velocity component ( _D ^ref , _D ^ref ) of the velocity vector of the bucket blade tip is output to the contacts 35a and 36a of the changeover switches 35 and 36, and the operating lever 31 coordinates the signal indicating the bucket absolute angular velocity. Output to the conversion circuit 37.

The slope angle setting device 32 sets the angle n of the slope where the bucket blade tip should move, and outputs a signal indicating the slope angle n to the arithmetic circuit 34. The operating lever 33 sets the speed v at which the bucket blade tip should move, and outputs a signal indicating the speed v to the arithmetic circuit 34.

The arithmetic circuit 34 calculates each velocity component ( ^ref , ^ref ) of the velocity vector of the bucket blade tip point from the following equation based on the input signal indicating the slope angle n and the velocity v.

The signals indicating the speed components ( ^ref , ^ref ) thus obtained are applied to the contacts 35b and 36b of the changeover switches 35 and 36, respectively.

The change-over switches 35 and 36 switch the movable contact pieces 35c and 36c to the contacts 35b and 36b, respectively, when performing the finishing work of the slope accurately according to the preset slope angle, and the signals to be input to these contacts. To the coordinate conversion circuit 37, and when performing other work, the movable contact pieces 35c and 36c respectively contact the contacts 35a and 3a.
The signals input to these contacts are switched to 6a and output to the coordinate conversion circuit 37.

The coordinate conversion circuit 37 includes a stroke end detection circuit that detects whether or not the bucket 3 has reached the stroke end based on the input signal indicating the bucket angle γ. If the bucket 3 has not reached the stroke end by this detection circuit. When judged, the bucket is determined based on the signal indicating each velocity component ( _D ^ref , _D ^ref ) of the input velocity vector, the signal indicating the bucket absolute angular velocity, and the signal indicating the boom angle α, the arm angle β, and the boom angle γ. Boom rotation speed required to move the cutting edge point D according to the above speed vector
^ref , arm rotation speed ^ref and bucket rotation speed
^{The ref} is calculated (Equation (8)).

Further, when the bucket 3 reaches the stroke end and this is detected by the stroke end detection circuit in the coordinate conversion circuit 37, the coordinate conversion circuit 37 determines that the bucket blade tip point under the condition that the bucket 3 is fixed at the stroke end. The boom rotation speed ^ref and the arm rotation speed ^ref are calculated so that the speed vector of D matches the commanded speed vector (Equation (5) or (6)).
formula).

Boom rotation speed ^ref calculated as described above, the signal indicating the arm rotating speed ^ref and bucket turning speed ^ref is output as the target value for each corresponding working machine. Since the control system for controlling each working machine based on these target values is the same as that in FIG. 1, the same reference numerals as those in FIG. 1 are given and detailed description thereof is omitted here.

Although the present embodiment has been described on the premise that the vehicle body is on the ground that is not tilted, even if the vehicle body is tilted, the bucket blade tip point or the arm tip is corrected by correcting the tilt angle. The point can be controlled according to the commanded velocity vector. in this case,
The tilt angle of the vehicle body (upper swing body) in the direction in which the working machine is facing is measured by, for example, a pendulum inclinometer. Assuming that this inclination angle is ζ, the above equation (3) is Can be replaced with

Further, when the vehicle body is on a sloping ground and the vehicle revolves or runs on a sloping ground, and the inclination angle of the upper revolving structure changes, the angular velocity of the inclination angle is also detected to determine the inclination angle ζ and the inclination angle. It is also possible to eliminate the influence of the vehicle body inclination and the change of the vehicle body inclination based on the angular velocity, and control the bucket blade tip point or the arm tip point according to the commanded velocity vector. In this case, the above equation (3) is Can be replaced with

Further, in the present embodiment, the bucket constant ground angle control is achieved by giving a value − (+), which is the inverted sign of the sum of the boom rotation speed and the arm rotation speed, as the target speed of the bucket rotation speed. However, in order to keep the preset bucket ground angle θ constant, the position of the bucket angle γ may be controlled according to the boom angle α and the arm angle β. In this case, the target bucket angle γ ^ref can be obtained by the following equation: γ ^ref = (3/2) π− (α + β + θ) (11) The bucket ground angle θ can be given by integrating the bucket rotation speed command.

[Effects of the Invention] As described above, according to the present invention, the bucket blade tip point is reached even when the bucket reaches the stroke end during the movement control according to the velocity vector instructing the bucket blade tip point while performing the bucket ground angle constant control. Can be moved according to the speed vector instructed above, and it is possible to compensate for deterioration of linearity during straight line excavation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a schematic diagram used to show the configuration of a power shovel and constants and variables of each part, and FIG. 3 is another embodiment of the present invention. The block diagram shown in FIG. 4 (a) is a change state diagram of the working machine when the horizontal command V _X is given as the speed command of the arm tip point and the bucket ground angle constant control is performed, FIG. 4 (b). FIG. 8 is a change state diagram of the conventional working machine in the case where the speed command V _X of the arm tip point is still applied after the bucket reaches the stroke end. 1 ... Boom, 2 ... Arm, 3 ... Bucket, 4 ...
Boom cylinder, 5 ... Arm cylinder, 6 ... Bucket cylinder, 10,30, 31, 33 ... Operating lever, 11,37 ... Coordinate conversion circuit, 12 ... Boom angle detector, 13 ...
... Arm angle detector, 14 ... Bucket angle detector, 16 ... Boom rotation speed calculation circuit, 17,21,27 ... Compensator, 18, 22, 28 ... Flow control valve, 20 ... Arm rotation Dynamic speed calculation circuit, 26 ... Bucket rotation speed calculation circuit, 32 ... Slope angle setting device, 34 ... Calculation circuit, 35, 36 ... Changeover switch.

Continuation of the front page (56) References JP-A-60-152734 (JP, A) JP-A-60-95035 (JP, A) Actually developed JP-A-55-131357 (JP, U)

Claims (5)

[Claims] 1. A velocity vector setting means for setting a velocity vector for moving a bucket blade tip point on the plane including a boom, an arm and a bucket as a coordinate plane, and angle detection for detecting a boom angle and an arm angle, respectively. Means, a stroke end detecting means for detecting a stroke end of the bucket, a speed vector at the bucket turning point is set based on the speed vector set by the speed vector setting means and the detection angle of the angle detecting means. First computing means for respectively determining the boom rotation speed and arm rotation speed so as to match the speed vector, and second calculation means for determining the bucket rotation speed or the bucket rotation angle so that the ground angle of the bucket becomes constant. Calculating means and the velocity vector set by the velocity vector setting means And the condition that the bucket is fixed at the stroke end based on the angle detected by the angle detecting means, the boom rotation speed and the arm are adjusted so that the speed vector at the bucket blade tip point matches the speed vector set above. Third calculation means for obtaining the rotation speed, and when the stroke end detection means has not detected the stroke end of the bucket, outputs the calculation results of the first and second calculation means to detect the stroke end of the bucket. And a flow rate control means for controlling a pressure oil supply flow rate to the corresponding working machine cylinder based on the calculation result added from the switching means. Control device for work equipment in power shovel. 2. The speed vector setting means comprises one operation lever and means for setting the speed vector of the bucket blade tip point according to the operation direction and operation amount of the operation lever. A control device for a work machine in a power shovel according to the item. 3. A control device for a working machine in a power shovel according to claim 1, wherein said speed vector setting means comprises excavation speed command means and slope angle setting means. 4. The second arithmetic means reverses the sign of the boom rotation speed and the arm rotation speed or the sum of the boom rotation speed and the arm rotation speed of the actual machine obtained by the first calculation circuit. A control device for a working machine in a power shovel according to claim 1, wherein a value is obtained as a bucket rotation speed. 5. The second calculating means sets the bucket ground angle, and sets the set angle based on the set angle of the setting means and the boom angle and arm angle detected by the angle detection means. The control device for a working machine in a power shovel according to claim (1), wherein a bucket rotation angle is obtained so as to keep it constant.