JPH0823153B2 - Bulldozer blade attitude control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blade attitude control method for a bulldozer, in which a blade of the bulldozer is tilted and angled by a cylinder.

[Conventional technology]

As shown in FIG. 10, a mechanism in which a blade of a conventional bulldozer is tilted and angled by a cylinder is configured by connecting a bracket 2 on which a center pin of the blade 1 is arranged and a joint 4 of a C frame 3 to each other. 1 is arranged rotatably around two axes of the center pin and the joint 4 with respect to the C frame 3,
Two angle cylinders 5a and 5b and one tilt cylinder 6 are attached between the C frame 3 and the blade 1.

When the blade 1 is left or right angled, the lengths of the left and right angle cylinders 5a and 5b are changed while the length of the tilt cylinder 6 is fixed,
Further, when the blade 1 is tilted left or right, the length of the tilt cylinder 6 is changed while the lengths of the left and right angle cylinders 5a and 5b are fixed.

In the figure, 7 and 8 are lift cylinders, and 9 is a pitching rod.

[Problems to be solved by the invention]

However, the above-described conventional blade tilt and angle control devices have a large number of cylinders, which complicates the mechanism and increases the weight of the working machine.

The present invention has been made in view of the above circumstances. The number of cylinders for tilting and tilting the blade is set to two, the mechanism is simplified, the weight of the working machine is reduced, and only the tilt operation or the angle operation is performed. It is an object of the present invention to provide a blade attitude control method for a bulldozer, which can prevent the blade from making an unplanned attitude change when it is performed, or can correct an unplanned attitude change.

[Means and Actions for Solving Problems]

According to the present invention, the blade is connected to the C frame in a tiltable and angleable manner, and the tilt angle and the angle angle of the blade are uniquely defined by the combination of the lengths of the cylinders between the blade and the C frame. In a blade attitude control method for a bulldozer, in which first and second cylinders are arranged in a fixed manner, and the first and second cylinders are combined and controlled based on a tilt angle and an angle angle that are control targets, The tilt angle and the angle angle before being controlled are detected, these are stored as initial values, and a new target angle for changing any one of the tilt angle and the angle angle of the blade is instructed. During the combined control of the first and second cylinders by instructing the target angle, the other angle not instructed is detected, and the detected other angle and the Taking a difference between the initial value of the square of the angle, when the deviation exceeds the allowable range, the first, second
The cylinder control is prohibited to prevent an unexpected change in the attitude of the blade.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a perspective view showing an embodiment of a blade mechanism of a bulldozer to which the present invention is applied. In the figure, the blade 10 is connected to the C frame 11 so as to be tiltable and angleable. That is, the bracket 13 on which the center pin 12 of the blade 10 is arranged, and the C frame 11
The center shaft 14 is connected to the blade 10, and the blade 10 can rotate about the axis of the center pin 12 (angle direction) and about the axis of the center shaft 14 (tilt direction).

Between the blade 10 and the frame 11, the blade 10
Cylinders for tilting and tilting 15
And 16 are installed. This cylinder 15 and
16 are mounted asymmetrically with respect to the mounting site of blade 10 as shown, and cylinders 15 and 16 are
The combined operation allows the blade 10 to perform an angle operation and a tilt operation.

Next, a preferable mode of mounting the cylinders 15 and 16 will be described in detail.

That is, the two cylinders are attached so that the tilt angle and the angle angle determined by the left cylinder length and the right cylinder length have the relationship of the graph shown in FIG. In the figure, point O indicates the left and right cylinder lengths when both the tilt angle and the angle angle are zero. And
The relationship between the left and right cylinder lengths indicates that the arrow tilts in the direction of arrow A, the left tilt, the arrow B in the direction of right tilt, the arrow C in the left angle, and the arrow D in the right angle.

Further, as shown in Table 1, the relationship between the blade operation and the expansion and contraction of the left and right cylinders is that the cylinder stroke change is completely different for each of the four operations of left angle, right angle, left tilt, and right tilt.

4 and 5 are a plan view and a rear view of FIG. 2, respectively, showing a preferable mounting mode of the left and right cylinders 15 and 16. That is, according to such an attachment mode, as shown in Table 1, the left cylinder 15 is retracted at the left angle, the right cylinder 16 is extended, the left cylinder 15 is extended at the right angle, and the right cylinder 16 is retracted. , (See FIG. 6), the left and right cylinders both extend during left tilt, and the left and right cylinders both retract during right tilt (see FIG. 7).

Next, a device for controlling the cylinder will be described.

FIG. 1 is a block diagram showing an embodiment of a blade attitude control device for a bulldozer according to the present invention.

In the figure, tilt lever 20 and angle lever
22 designates the tilt angular velocity and the angle angular velocity of the blade 10, respectively.
24 and angle angular velocity signal generator 26 outputs an analog signal indicating the tilt angular velocity ^r and angle angular velocity ^r corresponding to the lever operation amount of the tilt lever 20 and the angle lever 22, respectively to the A / D converter 28.

The tilt angle sensor 30 and the angle angle sensor 32 detect the tilt angle and the angle angle of the blade 10, respectively, and are composed of, for example, potentiometers that detect the rotation angles of the center shaft 14 and the center pin 12 of the blade 10 shown in FIG. To be done. These tilt angle sensors
The angle angle sensor 32 and the angle angle sensor 32 output analog signals indicating the detected tilt angle α and angle angle β to the A / D converter 28, respectively.

The A / D converter converts each of the four input analog signals into a digital signal and outputs the digital signal to the central processing unit (CPU) 34.

Based on the four data ( ^r , ^r , α, β) input via the A / D converter 28, the CPU 34 uses the two cylinders 15 so that the blade 30 has the instructed tilt angle or angle angle. , 16 cylinder control values are calculated. Note that C
Details of the operation of the PU 34 will be described later.

The cylinder control value (flow rate command value for each cylinder) calculated by the CPU 34 is applied to the hydraulic valves 42, 44 via the amplifiers 38, 40. The hydraulic valves 42, 44 are supplied with pressure oil from a hydraulic source (not shown), and supply hydraulic oil of a required flow rate (including supply direction) according to the flow rate command value input via the amplifiers 38, 40. Add to cylinders 15 and 16.

As a result, the cylinders 15 and 16 each have a predetermined cylinder length, and the blade 10 is controlled so as to have the instructed tilt angle or angle angle.

Next, the operation of the CPU 34 will be described in detail with reference to the flowchart shown in FIG.

In FIG. 8, first, the current tilt angle α and angle β of the blade are input (step 100). next,
It is determined whether the tilt lever and the angle lever are both neutral (step 110). This determination is made based on whether or not the tilt angular velocity command ^r and the angle angular velocity command ^r are zero.

If the tilt lever and the angle lever are both neutral, the tilt angle α input in step 100
And angle angle β are stored as initial values (α ₀ , β ₀ ) respectively (step 190).

On the other hand, if at least one of the tilt lever and the angle lever is operated, step 120
, Where each cylinder length of the current cylinder 15, 16 L _L ,
Calculate L _R.

In this calculation, as described above, the left and right cylinders are provided so that the combination of the lengths of the left and right cylinders and the blade attitude (tilt angle, angle angle) have a one-to-one correspondence in this calculation. Conversely, the left and right cylinder lengths are obtained from the tilt angle and the angle angle.

That is, a conversion table for obtaining the left and right cylinder lengths based on the tilt angle and the angle angle is prepared in the memory 36 (FIG. 1) in advance from the relationship between the left and right cylinder lengths and the blade attitude shown in FIG. However, the left and right cylinder lengths determined by the tilt angle and the angle angle are read from this conversion table.

Next, the tilt angular velocity command ^r and the angle angular velocity command ^r are input (step 130), and the target tilt angle α ^r and the target angle angle β ^r are calculated from the following equations (step 14).
0).

As shown in the above equation, each target angle is obtained by adding the angle amplification amount instructed by the lever to each previous target angle. It should be noted that Δt represents the processing time of one cycle shown in this flowchart. Further, when the target angle for the first time is obtained, the initial values (α ₀ , β ₀ ) stored in step 190 are used.

From each target angle (α ^r , β ^r ) obtained as described above, the target cylinder length (L _L ^r , L _R ^r ) is performed in the same manner as in step 120 above.
(Step 150).

Next, the deviations Δl _L and Δl _R between the target cylinder length (L _L ^r , L _R ^r ) and the current cylinder length (L _L , L _R ) are The flow rate command values V _L and V _R to the left and right cylinders required to quickly set these deviations Δl _L and Δl _R to zero are calculated from the following equation: V _L = AΔl _L + BΔ _L + CΣΔl _{L · Δt V R = AΔl R +} BΔ R + CΣΔl R · Δt ...... determined from (3) (step 170). In the above equation, A,
B and C are the coefficients of proportional, derivative and integral compensation elements.

The flow rate command values V _L and V _R thus obtained are output from the CPU 34 as described above (step 180).

Next, steps 200 to 260 show the processing when the cylinder is overloaded and the hydraulic circuit that supplies pressure oil to the cylinder is relieved or the left and right cylinders do not move as instructed due to a malfunction.

That is, when a command to change only the tilt angle of the blade is given, if the left and right cylinders do not move as instructed, the angle angle changes from the initial value. Similarly, if the left and right cylinders do not move as instructed when a command for changing only the angle angle of the blade is given, the tilt angle changes from the initial value. Steps 200-260
Suppresses blade control and prevents unplanned posture changes of the blade when the angle changes, which should not have originally changed.

In step 200, it is determined whether the tilt lever or the angle lever has been operated. If the tilt lever is operated, enter the angle angle β that should not cause an angle change (step 210).
There determines whether contained within tolerance ± [Delta] [beta] ₀ from its initial value beta ₀ (step 220). If the angle angle β is within the allowable error ± Δβ ₀ , the flow rate cut described later is reset and the process returns to step 100 to return to step 100, the tilt control is continued, and the angle angle β
When exceeds the allowable error ± Δβ ₀ , a flow rate cut command is output and the inflow and outflow of pressure oil in the left and right cylinders is prohibited (step 250).

Similarly, when the angle lever is operated, the tilt angle α that should not cause an angle change is input (step 230), and this tilt angle α is within the allowable error ± Δα ₀ from its initial value α _0. Determine whether it is included (step 2
40). If the tilt angle α is within the allowable error ± Δα ₀ , the process returns to step 100 via step 260, the angle control is continued, and the tilt angle is within the allowable error ± Δα.
_When it exceeds ₀ , a flow rate cut command is output to prohibit the inflow and outflow of pressure oil in the left and right cylinders (step 25
0).

If the lever is set to neutral while the blade operation is prohibited, the process proceeds to step 190 and the initial values are rewritten to the current tilt angle and angle angle.
In step 220 or step 240, it is determined that the difference is within the allowable error. As a result, the flow rate cut command is reset in step 260, and the operation becomes movable again.

Next, an example of subsequent processing when the blade comes to an unexpected posture and stops will be described.

This process is to correct the unplanned change in the attitude of the blade when the blade operation is prohibited and the lever becomes neutral.

FIG. 9 is a flow chart for executing the above processing. It should be noted that the same processes as those shown in FIG. 8 (the portions surrounded by the alternate long and short dash line) are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, first, F is set to 1 (step 300).
This F is a flag indicating whether the blade needs to be modified "1" or "0".

If both the tilt lever and the angle lever are neutral in step 110, the process proceeds to step 305, where it is determined whether or not F = 1. If F = 1, no correction of the blade is necessary, so the current tilt angle α and angle angle β are stored as initial values (α ₀ , β ₀ ) (step 190).

Now, a case will be described in which one of the tilt lever and the angle lever is operated to change the blade attitude.

In this case, after the flow rate command value to the left and right cylinder with respect to the lever operated in step 180 (V _L, V _R) is output, the process proceeds to step 200, where whether the tilt lever is operated is determined . Then, when the tilt lever is operated, 1 is set in T (step 310), and when the angle lever is operated, 1 is set in A. (Step 315).

Now the blade is in an unplanned position, step 25
When the flow rate cut command is output at 0 and the blade stops, F is set to 0 (step 320) and step 1
Return to 00.

When the lever is neutralized in the above state, the process proceeds to step 305. Step 305 requires blade modification (F = 0)
Therefore, the routine proceeds to step 325, where it is determined whether the tilt lever is operated (T = 1) or the angle lever is operated (A = 1). Then, when the tilt lever is operated, the initial value β ₀ of the angle angle is input (step 330), and when the angle lever is operated, the initial value α ₀ of the tilt angle is input / output (step 33).
Five).

Then, when the tilt lever is operated, the target cylinder length (L _L ^r , L _R ^r ) is calculated based on the current tilt angle α and the initial value β ₀ of the angle angle, and the angle lever is operated. In this case, the target cylinder length (L _L ^r , L _R ^r ) is obtained based on the current angle angle β and the initial value α ₀ of the tilt angle (step 340). On the other hand, the current tilt angle α and angle β
The current left and right cylinder lengths (L _L , L _R ) are calculated on the basis of (step 345).

Next, the target cylinder length (L _L ^r ,
Deviation Δl _L , Δl _R between L _R ^r ) and current cylinder length (L _L , L _R ).
(Step 350), the absolute value of these deviations | Δl
_It is determined whether or not both _L |, | Δl _R | are within a certain allowable value ΔL near 0 (step 355).

If the absolute values | Δl _L |, | Δl _R | are both within the allowable value ΔL, the current cylinder length has reached the target cylinder length and it is determined that blade correction is no longer necessary and the routine proceeds to step 360, where Set 1 to F and return to step 100.

On the other hand, if any one of the absolute values | Δl _L |, | Δl _R | exceeds the allowable value ΔL, the process proceeds to step 365 to correct the blade, and here, it is determined in step 350. Calculate the flow rate command values V _L and V _R for the left and right cylinders based on the deviations Δl _L and Δl _R. The calculation of the flow rate command value is performed in the same manner as step 170.

Then, in step 365, the flow rate command values V _L and V _R are output, and the process returns to step 100. Needless to say, the flow rate cut command in step 250 is reset at this time.

The method of giving the target tilt angle and the target angle angle of the blade is not limited to this embodiment, and the target angle and the target angle may be directly given by, for example, a dial or the like. Further, the actual measurement of the cylinder length is not limited to this embodiment in which the tilt angle and the angle of the blade are converted, but the cylinder length may be directly measured.

Further, in the present embodiment, in step 355, it is determined whether or not the correction of the blade attitude is completed based on the magnitude of the deviation between the target cylinder length and the current cylinder length, but the invention is not limited to this. It may be determined that the correction of the blade attitude is completed when the angle that should not occur is returned to the initial value.

Furthermore, the method is not limited to the method of obtaining the flow rate command values for the left and right cylinders based on the target cylinder length, the actual cylinder length, and the deviation.
The flow rate ratio of the left and right cylinders required for right angle and left angle is prepared in advance in the memory table, and the desired flow rate ratio is read from the memory table based on the current blade posture and the tilt or angle operation command of the blade. The flow rate command values for the left and right cylinders may be determined so that the read flow rate ratio is obtained.

〔The invention's effect〕

As described above, according to the present invention, the number of cylinders for tilting and tilting the blade is two, so that the structure can be simplified. In addition, when performing combined control of the above two cylinders so that only tilt or angle movements are performed, prevent this from occurring when the blade changes its posture unplanned, and when it changes posture unplanned. Can fix this.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a blade control device for a bulldozer according to the present invention, FIG. 2 is a perspective view showing an embodiment of a blade mechanism for a bulldozer according to the present invention, and FIG. A graph showing a preferable relationship between the combination and the blade attitude, FIGS. 4 and 5 are plan views and rear views of FIG. 2, respectively, and FIGS. 6 and 7 are expansion and contraction relationships of the left and right cylinders at the time of tilting and tilting, respectively. FIG. 8, FIG. 8 and FIG. 9 are shown in FIG.
Flowchart showing the processing procedure according to the present invention of the CPU, the first
FIG. 0 is an exploded perspective view showing an example of a conventional blade mechanism. 10 …… Blade, 11 …… C frame, 12 …… Center pin, 14 …… Center shaft, 15,16 …… Cylinder, 20…
… Tilt lever, 22 …… angle lever, 30 …… tilt angle sensor, 32 …… angle angle sensor, 34 …… central processing unit (CPU), 36 …… memory, 42,44 …… hydraulic valve.

Claims (2)

[Claims] 1. A blade is tiltably and angularly connected to a C frame, and a tilt angle and an angle of the blade are uniquely determined by a combination of lengths of respective cylinders between the blade and the C frame. In a blade attitude control method for a bulldozer, in which first and second cylinders are arranged in an aspect, and the first and second cylinders are combinedly controlled based on a tilt angle and an angle angle that are control targets, the blade is controlled The tilt angle and the angle angle before being detected are stored, these are stored as initial values, and a new target angle for changing one of the tilt angle and the angle angle of the blade is instructed, During the combined control of the first and second cylinders by instructing an angle, the other angle not instructed is detected, and the detected other angle and the other angle are detected. The deviation of the other angle from the initial value is taken, and when the deviation exceeds an allowable range, the control of the first and second cylinders is prohibited, and the unplanned posture change of the blade is prevented. A method for controlling a blade attitude of a bulldozer, which is characterized in that. 2. When the instruction to change the target angle of the tilt angle and the angle angle of the blade is stopped after the control of the first and second cylinders is prohibited, the current angle of the one angle and the other angle of the other angle are stopped. The invention is characterized in that the stored initial values of the angles are respectively set as control target angles, and the first and second cylinders are further composite-controlled to correct an unplanned posture change of the blades. A blade attitude control method for a bulldozer according to item (1).