JPS6234889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the bucket angle of an arm-type working machine such as a loading hydraulic excavator or a backhoe hydraulic excavator.

In order to prevent earth and sand from falling when lifting the boom of a loading hydraulic excavator, or to maintain a constant digging angle when excavating slopes or horizontal surfaces with a loading hydraulic excavator, it is necessary to It is necessary to keep the angle of the bucket from the horizontal plane, that is, the absolute angle, constant, and such operations require advanced techniques and a great deal of effort. In order to solve this problem, the absolute angle of the bucket can be automatically kept constant without the need for bucket operation.There are several ways to do this: a link method, a hydraulic method, and an electrical method. Several methods have been proposed.

FIG. 1 is a diagram showing the front part of a loading hydraulic excavator. In the figure, 1 is the main body of the hydraulic excavator, 2 is the boom that is pivotally attached to the main body 1, 3 is the arm that is pivoted to the tip of the boom 2, 4 is the bucket that is pivoted to the tip of the arm 3, and 5 is the boom that is raised and raised. 6 is an arm cylinder that swings the arm 3; 7 is a bucket cylinder that rotates the bucket 4; 8 detects the angle of the boom 2 with respect to the main body 1, that is, the boom angle; and 8 detects the boom angle signal α.
An angle meter 9 detects the angle of the arm 3 with respect to the boom 2, that is, the arm angle, and outputs an arm angle signal β; 10 detects the angle of the bucket 4 with respect to the arm 3, that is, the bucket angle; It is an angle meter that outputs a signal γ.

FIG. 2 is a diagram showing an apparatus for implementing a conventional bucket angle control method. 11,1 in the figure
2 is a hydraulic pump; 13 is a manually operated valve provided between the hydraulic pump 11 and the bucket cylinder 7;
4 is a bucket operation lever for operating the manually operated valve 13; 15 is an electromagnetic control valve provided between the hydraulic pump 12 and the bucket cylinder 7; 16 is the total value of the angle signals α, β, and γ, that is, the absolute value; An adder for calculating the angle signal δ; 17 a storage device for storing the output signal δ of the adder 16 when the switch 18 is turned on, that is, the target absolute angle signal δ _p ; 19 an output signal δ _p of the storage device 17; An adder/subtractor 20 calculates the difference with the output signal of the adder 16, that is, an angular deviation signal Δγ. 20 is a coefficient multiplier that multiplies the output signal of the adder/subtractor 19 by a coefficient and outputs a signal kΔγ. 21 is a coefficient when the switch 22 is on. This is an amplifier that amplifies and compensates the output signal of the bucket cylinder 20 and controls the electromagnetic control valve 15 to give an appropriate speed to the bucket cylinder 7. The switches 18 and 22 are turned on when the bucket operating lever 14 is placed in the neutral position. becomes.

In this device, the bucket operating lever 14
When the bucket cylinder 7 is in the operating position, the bucket cylinder 7 moves at a speed corresponding to the amount of operation of the bucket operating lever 14.
operates, and the angular velocity of the bucket belt 4 also takes on a value corresponding to the amount of operation of the bucket steering lever 14. Then, when the bucket operating lever 14 is returned to the neutral position and at least one of the boom 2 and arm 3 is operated, the switches 18 and 22 are turned on, and the target absolute angle signal δ _p at that time is stored in the storage device 17 and added/subtracted. The angular deviation signal Δγ is outputted by the device 19, the signal kΔγ is outputted from the coefficient unit 20, the electromagnetic control valve 15 is switched by an amount corresponding to the signal kΔγ by the amplifier 21, and the bucket cylinder 7 is set at a speed corresponding to the signal kΔγ. Because it works, Bucket 4
The angular velocity of is a value corresponding to the signal kΔγ. Incidentally, the absolute angle θ of the bucket belt 4 is expressed by the following equation, where A, B, and Γ are the boom angle, arm angle, and bucket angle, respectively.

θ=A+B+Γ+C Here, C is a constant value determined by the shape of the bucket 4, etc. Therefore, the absolute angle signal δ≡
Since α+β+γ is a value according to the absolute angle θ,
In order to keep the absolute angle θ constant, the absolute angle signal δ may be kept constant. In this device, the bucket belt 4 is rotated at an angular velocity according to the difference between the target absolute angle signal δ _p and the absolute angle signal δ, that is, the angular deviation signal Δγ. Therefore, even if the angle signals α, β, and γ change, the absolute angle θ of the bucket belt 4 is maintained at the absolute angle when the manual operation of the bucket belt 4 is stopped. In this state, when the bucket operating lever 14 is set to the operating position, the switches 18 and 22 are turned off, and the bucket 4 rotates at an angular velocity according to the amount of operation of the operating lever 14.

That is, in the conventional bucket belt angle control method, when at least one of the boom 2 and arm 3 is operated, the bucket belt angle signal when the absolute angle θ of the bucket belt 4 becomes constant, that is, the target bucket belt angle signal γ _r = δ _p −α−β is determined to determine the difference between the target bucket angle signal γ _r and the actual bucket tilt angle signal γ, that is, the angular deviation signal Δr.

Δγ=δ _p −δ=δ _p −α−β−γ=γ _r −γ And the signal k obtained by multiplying the angular deviation signal Δγ by the gain
The bucket belt 4 is rotated at a speed corresponding to Δγ, and in order to rotate the bucket belt 4 at a certain speed, it is necessary that the angular deviation signal Δγ is always not zero. By the way, normally the angular deviation signal Δγ can be kept small by increasing the gain k of the control system, but in a system with a large delay such as a hydraulic excavator, increasing the gain k will cause hunting. The gain k must be made small, and in this case the angular deviation signal Δγ becomes considerably large, making it impossible to accurately control the bucket angle.

In addition, in the conventional bucket angle control method,
The target absolute angle signal δ _p corresponding to the absolute angle θ of the bucket 4 when manual operation of the bucket 4 is stopped is stored, and the absolute angle θ of the bucket 4 is kept constant even when the boom 2 and arm 3 are operated. When manual operation of the bucket 4 is started in this state, the automatic control is stopped and the bucket 4 is rotated at an angular velocity corresponding to the amount of operation of the bucket 4. Therefore, when the bucket handle 4, which was rotating at a predetermined angular velocity during automatic control, operates the bucket handle operation lever 14, it starts rotating at an angular velocity that is unrelated to the previous angular velocity, resulting in a smooth operation feeling. I can't. For example, when the bucket belt 4 is rotating clockwise in Figure 1 at an angular velocity γ = ₁ to keep the absolute angle θ of the bucket belt 4 constant during automatic control, the operator When the bucket handlebar 4 is rotated clockwise with the intention of making a small correction, the angular velocity of the bucket handler 4 commanded by the bucket handler 14 is γ 〓 ₂
If the angular velocity γ is smaller than ₁ , the absolute angle θ of the bucket 4 will not become smaller but will instead become larger, which is contrary to the operator's intention and is dangerous. In order to solve this problem, when the bucket operation lever 14 is operated during automatic control, the output signal of the bucket operation lever 14 may be added to the target absolute angle signal δ _p , but in this case, the cost and the There are problems such as responsiveness, which makes it difficult to realize at present.

This invention was made to solve the above-mentioned problems, and the bucket angle can be controlled with high accuracy.
Another object of the present invention is to provide a bucket belt angle control method for an arm-type work machine that allows smooth adjustment of the absolute bucket angle during automatic control.

In order to achieve this object, the present invention includes a first working arm that is pivotally connected to the work machine body and is moved up and down by a first hydraulic cylinder, and a first working arm that is pivotally connected to the tip of the first working arm and is swung by a second hydraulic cylinder. In the method for controlling the bucket angle of an arm-type working machine, which includes a second working arm that is moved, and a bucket that is attached to the tip of the second working arm and rotated by a bucket cylinder, the angular velocity of the first working arm is controlled. and the angular velocity of the second working arm to obtain a control speed signal corresponding to the angular velocity at which the bucket should move, and
The angles of the working arm, the second working arm, and the bucket are detected, and the angles are corrected based on the angles of the first working arm, the second working arm, and the bucket according to the difference between the target angle and the actual angle of the bucket. The signal is obtained, and when the first working arm and the second working arm are operated, the bucket is rotated at an angular velocity according to the signal obtained by adding the control speed signal and the angle correction signal, and the first work arm is operated. When the bucket belt is manually operated when operating the second working arm, the bucket belt is rotated at an angular velocity according to a signal obtained by adding the control speed signal and the manual operation signal of the bucket handle, and When operating the working arm and the second working arm, the bucket is rotated at an angular velocity according to a signal obtained by adding the control speed signal and the angle correction signal, and the first working arm and the second working arm are rotated. When the bucket door is manually operated, the bucket door is rotated at an angular velocity according to a signal obtained by adding the control speed signal and the manual operation signal of the bucket door.

FIG. 3 is a diagram showing an apparatus for carrying out the bucket angle control method for an arm-type working machine according to the present invention. In the figure, 23 is an adder that calculates the sum of the boom angle signal α and the arm angle signal β, 24 is a differentiator that differentiates the output signal α+β of the adder 23, and 25 is the output signal kΔγ of the coefficient unit and the output signal of the differentiator. α+
An adder for calculating the difference between β≡−γ〓 _r , 26 a manual operating device that outputs a signal according to the amount of operation of the bucket operating lever 14, and 27 an output signal of the adder 25 and an output signal of the manual operating device 26. 28 is a switch provided between the adder 25 and the adder 27, 29 and 30 are respectively a boom operating lever and an arm operating lever, and 31 to 33 are operating levers 29, 30, A lever operation detector detects the operation state of 14, 34 is the operation lever 2
A control command that outputs a control signal A when at least one of the operating levers 29 and 30 is in the operating position, and outputs a control signal B when at least one of the operating levers 29 and 30 is in the operating position and the operating lever 14 is not in the operating position. In the device, when control signal A is output, switch 28 is turned on, and when control signal B is output, switches 18 and 22 are turned on.

FIG. 4 is a diagram showing an example of the control command device 34. In the figure, 35 is an OR element, 36 is an inverter, and 37 is an AND element.

FIG. 5 is a diagram showing another example of the control command device 34. In the figure, 38 and 39 are the operating levers 2
A switch 40 that is turned on when the operating levers 9 and 30 are in the operating position is a switch that is turned on when the control lever 14 is not in the operating position.

In this device, the bucket operating lever 14
When operating only the control command device 34
Since the control signals A and B are not output from the switch 18, 22, and 28 are off, the solenoid control valve 1
5 is switched by an amount corresponding to the amount of operation of the bucket operation lever 14, and the angular velocity of the bucket 4 has a value corresponding to the amount of operation of the bucket operation lever 14. Further, if at least one of the operating levers 29 and 30 is operated but the operating lever 14 is not operated, the control signals A and B are output from the control command device 34, so that the switches 18, 22, and 28 are turned on. Therefore, the bucket 4 receives the output signal γ〓 _r of the adder 27
It is rotated at an angular velocity according to +kΔγ. By the way, as mentioned above, the absolute angle signal δ corresponding to the absolute angle θ of the bucket 4 is expressed by the following equation.

δ=α+β+γ Then, when the absolute angle θ is constant, that is, when the absolute angle signal δ is constant, the following expression is obtained by differentiating this expression.

γ〓=−α〓−β〓 Therefore, if the angular velocity of the bucket 4 is a value according to the control speed signal −α〓−β〓≡γ〓 _r , the bucket 4
The absolute angle θ becomes constant. When the absolute angle θ varies from the absolute angle θ at the start of operation of the operating levers 29 and 30 due to the influence of disturbance, the angular velocity of the bucket 4 is corrected at a speed according to the signal kΔγ proportional to the amount of variation, The absolute angle θ of the bucket 4 is kept constant. Next, when the bucket control lever 14 is also operated in this state, only the control signal A is output from the control command device 34, so that the switches 18 and 22 are turned off. Therefore, since the bucket belt 4 rotates at an angular velocity according to the signal obtained by adding the output signal of the manual operation device 26 to the control speed signal γ _r It can be corrected at a corresponding speed. Next, when the bucket control lever 14 is returned to the neutral position in this state, the control signal B is output from the control command device 34, and the switch 1
8 and 22 are turned on, the target absolute angle signal δ _p having a value corresponding to the absolute angle θ at that time is stored in the storage device 17, and the bucket 4 holds that absolute angle θ from then on.

FIG. 6 is a diagram showing a part of another device for implementing the bucket angle control method for an arm-type working machine according to the present invention. In the figure, 41 is a switch provided between the adder 25 and the amplifier 21, and the switch 41 is turned on when the output signal A of the control command device 34 is output.

In this device, the bucket operating lever 14
When only the bucket handle lever 14 is operated, the switch 41 is off, and the bucket handle 4 is rotated at an angular velocity according to the amount of operation of the bucket handle operation lever 14. Further, one of the operating levers 29 and 30 is set to the operating position,
When the bucket control lever 14 is set to the neutral position, the bucket 4 outputs the output signal γ〓 _r +k of the adder 25.
Since it is rotated at an angular velocity according to Δγ, the absolute angle θ of the bucket 4 is kept constant. If the bucket operating lever 14 is also set to the operating position in this state, the pressure oil from the hydraulic pump 11 is also supplied to the bucket cylinder 7, so that the absolute angle θ of the bucket 4 can be changed. Furthermore, when the bucket steering lever 14 is returned to the neutral position from this state, the bucket steering wheel 4 maintains the absolute angle θ at that time.

That is, in the bucket belt angle control method according to the present invention, in order to keep the absolute angle θ of the bucket belt 4 constant while operating the boom 2 and arm 3, the angular velocity signals α〓 and β of the boom 2 and arm 3 are adjusted. A control speed signal -α〓-β〓≡γ〓 _r is obtained from 〓, and open loop control is performed by rotating the bucket 4 at an angle according to this control speed signal γ〓 _r . Therefore, compared to the conventional position feedback control method in which the angular velocity of the bucket 4 is controlled using the angular deviation signal Δγ, the open loop control according to the present invention has a faster response and does not cause hunting. changes in system parameters such as load weight,
If the influence of disturbances such as when the bucket belt 4 hits something is small, the bucket belt angle can be controlled with high precision. In the bucket angle control method according to the present invention, position feedback control is also performed using the angle deviation signal, that is, the angle correction signal Δγ, so the control is a combination of open loop control and position feedback control.
Even if the system parameters change, the influence of disturbance, etc. are large, the resulting change in the absolute angle θ can be corrected by position feedback control, so the bucket angle can be controlled with extremely high accuracy.

Further, in the bucket angle control method according to the present invention, the bucket _angle is
When the bucket control lever 14 is operated in this state, the manual operation signal of the bucket is used instead of the angle correction signal Δγ as the control speed signal γ
Since the absolute angle θ is added to _r , the absolute angle θ can be changed at a speed according to the manual operation signal, so that the absolute angle θ of the bucket can be smoothly corrected during automatic control.

In addition, in the above-mentioned Example, although the bucket angle control method of the hydraulic excavator was demonstrated, it is not limited to a hydraulic excavator. Further, in the above-described embodiment, a method for controlling the bucket angle of a loading hydraulic shovel has been described, but the method is exactly the same for a backhoe hydraulic shovel. Furthermore, one end of the bucket cylinder 7 is pivotally connected to the boom 2 instead of the arm 3, so that even if the arm 3 is swung, the absolute angle θ of the bucket cylinder 4 is automatically kept almost constant; In the case of a loader-like structure consisting of only a bucket 4, the control speed signal γ〓 _r is obtained from the angular velocity signal α〓 of the boom 2, and the angle correction signal Δ is calculated from the boom angle signal α and the bucket angle signal γ.
You may also find γ. In the above embodiment, the boom angle signal α, the arm angle signal β, and the bucket angle signal γ are directly detected by the angle meters 8 to 10, but the angle The signals α, β, and γ may also be determined indirectly. Furthermore, in the above embodiment, the angular velocity signals α〓, β〓 were indirectly obtained by differentiating the angular signals α, β, but the angular velocity signals α〓, β〓 may also be obtained directly. , values corresponding to the angular velocity signals α〓, β〓 such as the speeds of the cylinders 5 to 7 and the flow rates of the pipes connected to the cylinders 5 to 7 may be used. Further, in the above embodiment, the lever operation detectors 31, 3
2 detected the operation status of the operating levers 29 and 30, but as in slope excavation, the boom 2 and arm 3
When automatically controlling the operating levers 29 and 30 in a certain relationship, the operating states of the operating levers 29 and 30 may be detected using the automatic control signal, and the operating states of the operating levers 29 and 30 may be detected using the angular velocity signals α and β of the boom 2 and the arm 3, respectively. Thirty operating states may be detected. Furthermore, the arithmetic unit may be configured with an analog circuit or a digital circuit such as a microcomputer. Alternatively, the electromagnetic control valve 15 may be a combination of an electro-hydraulic conversion valve and a pilot-operated flow control valve, and the manual operation signal may be taken out as pilot pressure and added to the pilot pressure from the electro-hydraulic conversion valve. Furthermore, instead of controlling the cylinder 7 by controlling a valve such as the electromagnetic control valve 15, the cylinder 7 may be controlled by controlling the discharge amount of a pump that is a fluid pressure source.

As described above, in the bucket belt angle control method for an arm-type work machine according to the present invention, the bucket belt angle can be controlled with high precision, and the absolute angle of the bucket can be smoothly corrected during automatic control. As described above, the effects of this invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the front part of a loading hydraulic excavator, FIG. 2 is a diagram showing a device for implementing the conventional bucket belt angle control method, and FIG. 3 is a diagram showing a device for implementing the bucket belt angle control method according to the present invention. FIG. 4 and FIG. 5 are diagrams each showing an example of a control command device, and FIG. 6 is a diagram showing a part of another device for carrying out the bucket angle control method according to the present invention. It is. 1...Hydraulic excavator body, 2...Boom, 3...
...Arm, 4...Bucket, 5...Boom cylinder, 6...Arm cylinder, 7...Bucket cylinder, 8-10...Angle meter, 13...Manual operation valve, 14...Bucket operation lever, 15 ... Solenoid control valve, 16 ... Adder, 17 ... Memory device, 1
8... switch, 19... adder/subtractor, 22... switch, 23... adder, 24... differentiator, 25
...Adder, 26...Manual operating device, 27...Adder, 28...Switch, 29...Boom operation lever, 30...Arm operation lever, 31-33...
... Lever operation detector, 34 ... Control command device, 4
1...Switch.

Claims (1)

[Scope of Claims] 1. A first working arm which is pivotally connected to the working machine body and is moved up and down by a first hydraulic cylinder, and a first working arm which is pivotally connected to the tip of the first working arm and is swung by a second hydraulic cylinder. In the method for controlling the bucket angle of an arm-type working machine equipped with two working arms and a bucket that is attached to the tip of the second working arm and rotated by a bucket cylinder, the angular velocity of the first working arm and the second bucket can be controlled. A control speed signal corresponding to the angular velocity at which the bucket belt should move is determined from the added value with the angular velocity of the working arm, and the angles of the first working arm, the second working arm, and the bucket belt are detected; , an angle correction signal corresponding to the difference between the target angle and the actual angle of the bucket is calculated from the angles of the second working arm and the bucket, and when the first working arm and the second working arm are operated, the control speed is adjusted. A bucket belt angle control method for an arm-type work machine, characterized in that the bucket belt is rotated at an angular velocity according to a signal obtained by adding a signal and the angle correction signal. 2. The target angle of the bucket can be determined by calculating the absolute angle of the bucket at the start of operation of the first working arm and the second working arm or the end of the operation of the bucket and the angle of the first working arm and the second working arm. 2. A bucket angle control method for an arm-type working machine according to claim 1, wherein the bucket angle is determined from the angle. 3. A first working arm that is pivotally connected to the work equipment body and is moved up and down by a first hydraulic cylinder; a second working arm that is pivotally connected to the tip of the first working arm and is swung by a second hydraulic cylinder; In a bucket angle control method for an arm-type working machine equipped with a bucket that is attached to the tip of a second working arm and rotated by a bucket cylinder, the angular velocity of the first working arm and the angular velocity of the second working arm are A control speed signal corresponding to the angular velocity at which the bucket tote should move is determined from the added value, and when the bucket tot is manually operated when operating the first working arm and the second working arm, the control speed signal and the manual operation of the bucket tote are determined. A bucket belt angle control method for an arm-type work machine, characterized in that the bucket belt is rotated at an angular velocity according to a signal obtained by adding a signal. 4. A first working arm that is pivotally connected to the work equipment body and is moved up and down by a first hydraulic cylinder; a second working arm that is pivotally connected to the tip of the first working arm and is swung by a second hydraulic cylinder; In a bucket angle control method for an arm-type working machine equipped with a bucket that is attached to the tip of a second working arm and rotated by a bucket cylinder, the angular velocity of the first working arm and the angular velocity of the second working arm are A control speed signal corresponding to the angular velocity at which the bucket should move is determined from the added value, and the angles of the first working arm, the second working arm, and the bucket are detected, and the first working arm, the second working arm An angle correction signal corresponding to the difference between the target angle and the actual angle of the bucket is determined from the angle of the bucket, and when the first working arm and the second working arm are operated, the control speed signal and the angle correction signal are calculated. When the bucket is rotated at an angular velocity according to the signal obtained by adding the above control speed signal and the manual operation signal of the bucket, when the bucket is manually operated when the first working arm and the second working arm are operated, A bucket belt angle control method for an arm-type work machine, characterized in that the bucket belt is rotated at an angular velocity according to a signal obtained by adding up the bucket belt.