JPH0745743B2 - Linear excavation control device for hydraulic excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a straight line excavation work for moving a bucket in a constant posture in parallel with the excavation ground, such as slope excavation (finishing) work and work for horizontally excavating a groove bottom. The present invention relates to a straight line excavation control device for carrying out.

(Prior Art) Conventionally, as a linear excavation control device for a hydraulic excavator, a boom (boom cylinder), an arm (arm cylinder), and a bucket (bucket cylinder) are all controlled based on a speed command signal from an operator's lever operation. Various automatic control configurations have been proposed.

However, during normal manual excavation work, the operator defines one of the arm and boom beam members as a control reference, and activates the reference beam member at the same time by operating the lever to cause the beam member to follow it. Since it is customary to control the operation of the other beam member and the bucket by operating another lever as described above, according to the conventional device that directly controls the bucket, the operation feels uncomfortable compared with the normal excavation work. However, there is a problem in terms of operation feeling that the arm does not move as intended by the operator, for example, although the operating speed of the arm is instructed by operating the lever with a sense of operation during normal work.

In addition, since all the movements of the boom, arm, and bucket have to be calculated by the controller, the required calculation capacity becomes large, the hardware cost becomes high, and the error factors increase and the control accuracy becomes poor. There were also problems such as

(Object of the Invention) Therefore, according to the present invention, one of the boom member and the arm member is manually controlled by lever operation with the beam member as a reference, and the other beam member and bucket are operated at the operating speed of the reference beam member. The present invention provides a linear excavation control device for a hydraulic excavator, which can be automatically controlled according to the above, and can realize improved operation feeling, cost reduction, and improved control accuracy.

(Structure of the Invention) The present invention relates to a boom, an arm pivotally attached to the tip of the boom, a bucket pivotally attached to the end of the arm, a boom cylinder for raising and lowering the boom, and a rotation of the arm. In a hydraulic excavator including a dynamically driven arm cylinder and a bucket cylinder that rotationally drives the bucket, an operating lever for manually controlling one of the boom cylinder and the arm cylinder, and one of the above-mentioned ones by the operating lever. Command speed detecting means for detecting an operation command speed for the cylinder, boom angle detecting means for detecting a boom angle, arm angle detecting means for detecting an angle of the arm with respect to the boom, and bucket angle detecting means for detecting a bucket angle, The detection signal from each of these detection means, the target value of the height of the bucket above ground, and the bucket angle A controller for inputting a target value and a target value for the excavation angle, respectively, and the controller, based on the respective inputs, performs feedforward control on a cylinder not manually controlled among the boom cylinder and the arm cylinder, and a bucket cylinder. It has means for calculating the control amount and the feedback control amount and outputting the control amounts of these two cylinders.

With this configuration, the other beam member and the bucket are automatically controlled according to the operating speed of the manually controlled reference beam member, so that the operation feeling becomes closer to that during normal manual excavation work, and the sense of discomfort in operation is eliminated. . Further, since the number of objects to be automatically controlled is reduced, the required calculation processing capacity can be reduced, which is advantageous in terms of cost and, at the same time, improvement in control accuracy can be expected due to the reduction of error factors.

(Example) An example of the present invention will be described with reference to the drawings.

In FIG. 3, reference numeral 1 is a revolving structure of the hydraulic excavator main body, 2 is a boom pivotably attached to the revolving structure 1, and an arm 3 is provided at the tip of the boom 2 and a bucket 4 is provided at the end of the arm 3. It is pivotably attached. Reference numeral 5 is a boom cylinder that drives the boom 2 up and down, 6 is an arm cylinder that rotationally drives the arm 3, and 7 is a bucket cylinder that rotationally drives the bucket 4.

This hydraulic excavator includes a boom 1 as shown in FIG.
The boom angle detector 8 for detecting the ground angle θ ₁ of the boom ₂ , the arm angle detector 9 for detecting the angle α 2 of the arm 3 with respect to the boom 2, and the bucket angle detector 10 for detecting the ground angle of the bucket 4 are respectively boom 2, The operation speed (command speed) of an arm lever (not shown) for manually controlling the arm 3 is provided in each of the pivot points of the arm 3 and the bucket 4 or in the vicinity of the pivot points and in the operation room of the revolving structure 1. Arm lever pilot pressure detector 11,12 that detects by the pilot pressure of the remote control valve in both up and down directions
An excavation angle setting switch 13 and an automatic / manual switch 14 are provided. Figure 3 shows slope excavation (finishing)
In the case of work, the inclination angle β of the slope (excavation ground) G is set by the excavation angle setting switch 13 as the target excavation angle.

In the following, the case where the excavation surface is a horizontal plane will be described, but in the case of slope excavation shown in FIG. 3, based on the coordinate axes x ′ and y ′ rotated by the excavation angle β with respect to the horizontal coordinate axis x and the vertical coordinate axis y. Coordinate calculation of the arm tip B position is performed.

On the other hand, when the automatic / manual switch 14 is set to the automatic side, the height position of the arm tip (bucket pivot point with respect to the arm 3) B at this time, that is, the bucket height position yb, and the bucket ground angle θ. ₃ is set as the target value.

In FIG. 3, α ₃ is the bucket angle with respect to the boom 3, l ₁ is the distance from the boom base end O to the boom tip A (boom length), and l ₂ is the distance from the boom tip A to the arm tip B (arm length). Respectively) are shown.

Detection signal of each of the above detectors 8 to 12, excavation angle setting switch
The switch signal of the automatic / manual changeover switch 14 is input to the controller 15. The controller 15 outputs a control signal for the arm cylinder 6 to the arm cylinder hydraulic pressure control unit 16 based on the arm lever operation, and
The bucket 4 is moved to the third position while keeping the ground height position y _b of the arm tip B and the bucket ground angle constant (target values), respectively.
The control amount of the boom 2 (boom cylinder 5) and the bucket 4 (bucket cylinder 7) required for linear movement in the direction of the arrow in the figure is calculated, and this is output to the boom cylinder hydraulic pressure control unit 17 and the bucket cylinder hydraulic pressure control unit 18. To do.

Each of the cylinder hydraulic pressure control units 16, 17, 18 includes an electromagnetic proportional pressure reducing valve and a switching valve (not shown) that is operated by the secondary pressure of the pressure reducing valve. The amount of pressure oil supplied to each cylinder 6, 5, 7 of the boom and bucket, that is, the cylinder operating speed is controlled.

The function of the controller 15 will be described with reference to the functional block diagram of FIG.

The controller 15 includes an arm control block 15a, a boom control block 15b, and a bucket control block 15c.

(I) Arm control block 15a In this block 15a, the arm lever signal (speed command signal) from the arm lever pilot pressure detector 11 or 12 is multiplied by a predetermined gain by the calculating means 19 to obtain the basic control amount u ₂₁ . Then, the correction by the arm link correction means 20 is added to this to obtain the primary correction control amount u _22, and the secondary correction control amount u ₂ obtained by further adding the correction by the non-linear compensation means 21 to the arm cylinder hydraulic pressure control unit 16 Is output as a control amount for.

The arm link correction means 20 applies a predetermined correction so that the expansion / contraction speed of the arm cylinder 6 and the rotational angular speed of the arm 3 are not in a proportional relationship so that these relationships are maintained in a proportional relationship throughout the entire cylinder stroke. . Further, the non-linear compensating means 21 controls the output current to the electromagnetic proportional pressure reducing valve in the arm cylinder hydraulic pressure control unit 16 due to the dead zone of the electromagnetic proportional pressure reducing valve, the non-linearity between the spool stroke and the opening of the switching valve, and the like. The linearity is maintained by correcting the non-linearity between the value and the expansion / contraction speed of the arm cylinder 6.

In this way, the arm 3 is manually controlled at a constant angular velocity according to the commanded velocity by operating the arm lever.

(II) Boom control block 15b In this block 15b, the present boom angle θ ₁ and arm angle α _{2 from} the boom angle and arm angle detectors 8 and 9 are input, and these angle signals and arm control block 15a Based on the basic control amount u ₂₁ , the boom cylinder feedforward calculation means 22 causes the arm tip B
The boom cylinder feedforward amount u ₁₁ is calculated to keep the height position y _b of the boom constant. The contents of this calculation are as follows.

The height position y _b of the arm tip B in FIG. 3 is y _b = l ₁ sin θ ₁ + l ₂ sin (θ ₁ −α ₂ ) (1) From this, the arm tip angular velocity y _b is _b = {l ₁ cos θ ₁ + l ₂ cos (θ ₁ −α ₂ )} θ ₁ −l ₂ co
s (θ ₁ −α ₂ ) ₂ (2) ₁ is the boom angular velocity, and ₂ is the arm angular velocity.

If y _{b is} constant, _b = 0 Using the above equation (3), the boom cylinder feedforward control amount u ₁₁ in FIG. Required by. Kff is the feedforward gain.

Further, the actual height position y _b of the arm tip B is obtained from the boom angle signal and the arm angle signal by the coordinate calculation means 23 by the coordinate calculation of the equation (1), and this calculated value
y _b and, from the deviation [Delta] y _b from the target value y _b0 arm tip height position, feedback control amount by a proportional integrating means 24 u ₁₂
Is calculated.

This feedback control amount u ₁₂ and the feedforward control amount u ₁₁ obtained by the equation (4) are added to form the boom cylinder basic control amount u ₁₃ , which is corrected by the boom link correction means 25 (first-order correction). The boom cylinder control output u ₁ is obtained by adding the control amount u ₁₄ ), the correction by the boom posture compensation means 26 (secondary correction control amount u ₁₅ ), and the correction by the non-linear compensation means 27. The boom link correcting means 25 is the arm link correcting means 21 in the arm control block 15a.
Similarly to the above, the correction for maintaining the proportional relationship between the expansion / contraction speed of the boom cylinder 5 and the rotation angle angle of the boom 2 is performed, and the non-linear compensating means 27, similarly to the non-linear compensating means 21, sends to the boom cylinder hydraulic control section 17. To compensate the linearity between the output current value and the boom cylinder speed. Also, boom attitude correction means
In consideration of the fact that the inertia moment of the boom 2 changes according to the boom angle θ ₁ , the boom cylinder pressure changes due to this, and the cylinder speed changes, the 26 indicates the boom angular speed by multiplying the correction gain according to the boom angle. Perform a correction to keep constant.

In this way, the boom 2 is controlled so that the arm tip B moves straight along the excavation surface G with the height of the arm being constant.

(III) Bucket control block 15c In this block 15c, the feedback control amount u is calculated by the proportional integration means 28 from the deviation Δθ ₃ between the detected value of the bucket angle θ ₃ by the bucket angle detector 10 and the bucket angle target value θ _{30. Ask} for ₃₂ . On the other hand, the basic control quantity u ₂₁ of the arm control block 15a, a basic control quantity u ₁₃ of the boom control block 15b is incorporated, by a bucket feedforward operation means 29, on the basis of the both control amounts u _21, u _13, The bucket cylinder feedforward control amount u ₁₃ in the direction in which the bucket angle θ ₃ matches the target value θ ₃₀ is calculated. That is, the bucket angle θ ₃ = θ ₁ −α ₂ −α
₃ ∴ ₃ = ₁ - ₂ - _{3 3} = 0 to the ₃ = ₁ - ₂ ... (5) (5) based on the equation _{u 31 = Kff (u 13 -u} 21), bucket feedforward control amount u ₃₁ Is required.

Then, the feedback control amount u ₃₂ and the feedforward control amount u ₃₁ are added to obtain the basic bucket control amount u
₃₃ is obtained, and similarly to the case of the arm control block 15a, the bucket cylinder control output is obtained by adding the correction by the bucket link correcting means 31 (first-order correction control amount u ₃₄ ) and the non-linear compensating means 32. Find u ₃ .

As a result, the ground angle θ ₃ of the bucket 4 is kept constant (target value), and this function is combined with the linear movement control function of the arm tip B by the boom control block 15b to perform slope excavation work.

By the way, in the above-mentioned embodiment, the case of the slope excavation work has been described as an example, but the present invention is a work for excavating the groove bottom horizontally,
The horizontal extrusion operation using a loading shovel can be performed in the same manner as above. In this case, the target excavation angle is 0
It becomes °. In addition, each block 15a, 15b, 15c shown in FIG.
Correction means 20, 25, 26, 30 and non-linear compensation means 2 in
It goes without saying that 1,27,31 are functionally useful,
It can be omitted in the case of work that does not require very precise excavation accuracy. Also, each link correction means 2
0, 25, 30 can be omitted if the operating ranges of the boom 2, the arm 3, and the bucket 4 are limited and the proportional relationship between the angular velocity and the cylinder velocity does not matter. Further, in the above-described embodiment, the arm 3 is taken as an example of the beam member to be manually controlled, but the boom 2 may be manually controlled.

(Effect of the Invention) When the linear excavation control device of the present invention is used as described above,
One of the arm member and the boom member is manually controlled by the lever operation of the operator, and the other beam member and the bucket are linearly operated at the command speed by the lever operation in conjunction with the operation of the manually controlled beam member. Since it is configured to automatically control so that the excavation function can be obtained, operation during this straight line excavation work and operation during normal excavation work in which one beam member operation is used as a reference to manually operate the other beam member and the bucket The feeling of discomfort is eliminated and the operation feeling is improved. Further, since the arithmetic processing by the controller may be performed mainly on the other beam member and the bucket, the arithmetic processing capacity of the controller can be small. Therefore, the hardware cost is low, and the error factors of the calculation are reduced, which is advantageous in terms of control accuracy.

[Brief description of drawings]

FIG. 1 is a control block diagram showing an embodiment of the present invention, FIG. 2 is a functional block diagram of a controller in the embodiment, and FIG. 3 is an external view of a hydraulic excavator for performing slope excavation work. 2 ... boom, 3 ... arm, 4 ... bucket, 5 ... boom cylinder, 6 ... arm cylinder, 7 ... bucket cylinder,
8 ... Boom angle detector, 9 ... Arm angle detector, 10 ... Bucket angle detector, 11, 12 ... Arm lever pilot pressure detector (command speed detecting means), 13 ... Excavation angle setting device, 14
… Automatic / manual switch (arm height position, bucket angle target value input means), 15… Controller, 15a… Controller arm control block, 15b… Boom control block, 15c… Bucket control block, 22,29 ... Feedforward calculation means, 23, 24, 28 ... Means for calculating the feedback control amount.

Claims (1)

[Claims] 1. A boom, an arm pivotally attached to the tip of the boom, and a bucket pivotally attached to the tip of the arm,
In a hydraulic excavator equipped with a boom cylinder for lifting and lowering the boom, an arm cylinder for rotationally driving the arm, and a bucket cylinder for rotationally driving the bucket, one of the boom cylinder and the arm cylinder is used. An operating lever for manual control, a command speed detecting means for detecting an operation command speed for the one cylinder by the operating lever, a boom angle detecting means for detecting a boom angle, and an arm angle detecting for detecting an angle of the arm with respect to the boom. Means, a bucket angle detecting means for detecting a bucket angle, and a controller to which a detection signal from each of these detecting means, a target value of the ground height position of the bucket, a target value of the bucket angle, and a target value of the excavation angle are input, respectively. Based on each of the above inputs, the controller A straight line of a hydraulic excavator, which has means for calculating a feedforward control amount and a feedback control amount for a boom cylinder and an arm cylinder that are not manually controlled and a bucket cylinder and outputting the control amounts of these cylinders. Excavation control device.