JPH0723620B2 - Excavation control device for hydraulic excavator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavation control device used for excavation work in which a bucket is moved while being held at a constant angle, such as slope excavation (finishing) work by a hydraulic excavator. It is a thing.

(Prior Art) Conventionally, in excavation work that requires keeping the bucket angle constant, such as slope excavation work with a hydraulic excavator and work that horizontally excavates a groove, the bucket angle is detected by a detector, and the detected value is detected. Based on the deviation from the target value of the bucket angle, a control device for performing so-called feedback control for controlling the bucket cylinder in the direction in which this deviation becomes smaller is disclosed in Japanese Patent Laid-Open No. 56-105030. Is known to

However, according to the conventional device that detects and controls only the bucket angle in this way, the above deviation becomes too large when the arm angular velocity becomes high, and the feedback control becomes difficult. Particularly, in the operation of pulling the arm cylinder toward the shovel body side by extending the arm cylinder, the above-mentioned deviation is increased due to the nonlinear characteristic of the arm that the angular velocity of the arm rapidly increases with respect to the operating speed of the arm cylinder at the end of pulling. This caused the so-called bucket control to be difficult.

(Object of the Invention) Therefore, the present invention provides an excavation control device for a hydraulic excavator, which can take in the arm angular velocity as an element for constant bucket angle control and perform appropriate control according to the arm angular velocity.

(Structure of the Invention) The present invention controls a boom, an arm, a bucket, a boom cylinder for driving the boom, an arm cylinder for driving the arm, a bucket cylinder for driving the bucket, and an operation of the bucket cylinder. The bucket cylinder hydraulic pressure control unit, the bucket angle detection unit that detects the bucket angle, the bucket angle target value setting unit that sets the target value of the bucket angle, and the deviation between the detected value and the target value of these bucket angles. In accordance with a hydraulic excavator having a bucket control means for calculating and outputting a feedback control amount for the bucket cylinder hydraulic control section, the arm cylinder hydraulic control section for controlling the operation of the arm cylinder and the angular velocity of the arm are controlled. The arm angular velocity detection means to detect and the maximum setting of the maximum value of the arm angular velocity. A large arm angular velocity setting means is compared with the detected value of the arm angular velocity and the set value, and when the detected value becomes larger than the set value, an arm that sends a signal in the direction of decelerating the arm cylinder to the arm cylinder hydraulic control section. A control means is provided.

With this configuration, when the arm angular velocity becomes larger than the set value, the arm cylinder is immediately decelerated and the arm angular velocity is suppressed, so that the deviation between the actual value of the bucket angle and the target value can be prevented from becoming excessive. Therefore, the feedback control of the bucket angle can be appropriately performed without difficulty.

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

In FIG. 3, 1 is a hydraulic excavator main body, 2 is a boom pivotably attached to the main body 1, and an arm 3 is attached to the tip of the boom 2 and a bucket 4 is attached to the tip of the arm 3 to be rotatable. It is pivotally 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.

FIG. 3 shows that while keeping the inclination angle α of the bucket 4 constant,
The case where a slope excavation work is performed in which the bucket 4 is linearly moved in the direction of the arrow along the slope G is shown. In this embodiment, the boom 2 is manually controlled in order to linearly move the bucket 4 in a constant angle state, and the arm 3 is basically manually controlled to automatically intervene only when the arm angular velocity is increased. The bucket 4 is automatically controlled.
β is the angle of the arm 3 with respect to the boom 2 (hereinafter referred to as the arm angle).

FIG. 1 shows a control block configuration of the bucket 4 and the arm 3.

In the figure, 8 is a bucket angle sensor for detecting the bucket angle α, 9 is an arm angle sensor for detecting the arm angle β, and angle signals (detection values) from these sensors 8 and 9 are shown.
α ₁ and β ₁ are input to the controller C. Further, the bucket angle target value α ₀ is input to the controller C by the bucket angle target value setting means 10, and the maximum allowable arm angular velocity β ₀ is input to the controller C by the maximum arm angular velocity setting means 11. The controller C is provided with a bucket control amount calculation unit 12, an arm angular velocity calculation unit 13, and an arm control amount calculation unit 14.

The bucket control amount calculation unit 12 uses the detected value α _{1 of the} bucket angle.
And a deviation of the target value α ₀ are calculated, a feedback control amount is calculated from this deviation, and the feedback control signal u ₁ is output to the bucket cylinder hydraulic control unit 15. On the other hand, the arm angular velocity calculation unit 13 obtains the arm angular velocity ₁ from the amount of change in the detected value β ₁ of the arm angle, and outputs this to the arm control amount calculation unit 14 as the detected value of the arm angular velocity. The arm control amount calculation unit 14 compares the detected value ₁ of the arm angular velocity with the set value ₀ by the maximum arm angular velocity setting means 11,
When the detected value ₁ becomes larger than the set value ₀ , a cylinder deceleration signal u ₂ is output to the arm cylinder hydraulic pressure control unit 16, and a steady signal u ₃ is output otherwise (hereinafter, referred to as normal time). The set value ₀ is the maximum value (limit value) of the arm angular velocity that is maintained within the range in which the deviation between the detected value α ₁ of the bucket angle and the target value α ₀ does not hinder the constant bucket angle control (feedback control). ).

The bucket cylinder hydraulic control unit 15 controls the bucket cylinder 7
A pilot type switching valve that controls the supply and discharge of pressure oil to and from
It is composed of an electromagnetic proportional valve (none of which is shown) for controlling the operation of this switching valve, and the switching valve is operated via the electromagnetic proportional valve by the feedback control signal u ₁ from the bucket control amount calculation unit 12, and the bucket cylinder 7 The operation is automatically controlled.

The configuration of the arm cylinder hydraulic control unit 16 is shown in FIG.

Reference numeral 17 is an arm lever for manual operation of the arm, 18 is an operation valve operated by the arm lever 17, and 18a and 18b are pushing arms which constitute the operation valve 18 (reduction of the arm cylinder).
Side and same side (arm cylinder extension) side pressure reducing valve,
Reference numeral 19 is an arm pushing side proportional solenoid valve, 20 is a pulling side proportional solenoid valve, 21 is a pilot type switching valve for controlling the supply and discharge of pressure oil to and from the arm cylinder 6, 22 is a pilot hydraulic pressure source, and 23 is a main hydraulic pressure source. . The pressure oil from the pilot hydraulic power source 22 is supplied to the push-side pressure reducing valve 18 of the operation valve 18 when the arm lever 17 is pushed.
a, supplied to the push-side hydraulic operating portion 21a of the switching valve 21 via the solenoid proportional valve 19, and at the time of pulling operation, pulls the pressure reducing valve 18b on the pulling side of the operating valve 18 and pulls the switching valve 21 via the solenoid proportional valve 20. It is supplied to the side hydraulic operating unit 21b.

The cylinder deceleration signal u ₂ and the steady signal u ₃ from the arm control amount calculation unit 14 in the controller C are applied as an exciting current to one electromagnetic operating unit 19a or 20a of the proportional solenoid valves 19 and 20. In this case, the steady signal u ₃ is supplied as the maximum exciting current, at which time the solenoid proportional valve 19 or 20 has the maximum opening. Therefore, at this time, the secondary pressure of the operation valve 18 is directly applied to the hydraulic operation section 21a or 21b of the switching valve 21 as the secondary pressure of the solenoid proportional valve 19 or 20. That is, in a normal state where the detected value _{1 of the} arm angular velocity is smaller than the set value ₀ , the arm cylinder 6 is manually controlled by the lever operation of the arm lever 17.

On the other hand, for example, when the detected value _{1 of the} arm angular velocity becomes larger than the set value ₀ due to the nonlinear characteristic of the arm operation that the arm angular velocity rapidly increases at the end of the arm pulling, the cylinder output from the arm control amount calculation unit 14 The deceleration signal u ₂ is supplied to the solenoid proportional valve 19 or 20 as an exciting current smaller than that of the steady signal u ₃ . Therefore, if this situation occurs during the arm pulling operation, the opening of the pull-side solenoid proportional valve 20 is throttled, the secondary pressure of the valve 20 decreases, and the switching valve 21 operates toward the neutral side.
The speed of is decreased and the angular velocity of the arm is suppressed. In this case, the cylinder deceleration signal u ₂ output from the arm control amount calculation unit 14 may be a constant current value regardless of the difference between the detected value _{1 of the} arm angular velocity and the set value ₀ , or the above difference The current value according to the magnitude, that is, the larger the difference, the smaller the current value may be.

In this way, when the arm angular velocity becomes too fast and the deviation between the detected value α ₁ of the bucket angle and the target value α ₀ becomes excessive and it becomes difficult to control the bucket constant angle by the bucket control system, the automatic intervention causes Arm cylinder 6
Can be decelerated immediately to lower the arm angular velocity and control so as to reduce the upper deviation.

Further, according to this configuration, the arm angular velocity control can always be properly performed without being affected by the load.

That is, in FIG. 2, the hydraulic pressure operating portion 21a of the switching valve 21,
Even if the secondary pressure signal sent to 21b is the same and the size of the opening area of the switching valve 21 is the same, the flow rate sent from the main hydraulic power source 23 to the arm cylinder 6 changes depending on the size of the load.
This changes the arm angular velocity.

In this case, according to this device, since the actual arm angular velocity is detected, regardless of the magnitude of the secondary pressure signal to the switching valve 21, if the actual arm angular velocity exceeds the set value, the desired arm angular velocity suppressing action is achieved. Is done accurately.

By the way, in the above-mentioned embodiment, the configuration in which the arm 3 is manually controlled is taken as an example, but in the case of automatically controlling the arm 3 as well, the same configuration as the above can be adopted as the automatic correction means for arm operation. Further, the present invention is not limited to the above-mentioned slope excavation work, but can be similarly applied to other excavation works in which control is performed to keep the bucket angle constant, such as work for horizontally excavating a groove.

(Effects of the Invention) As described above, according to the present invention, the arm angular velocity is taken in as a factor for controlling the constant bucket angle, and the arm angular velocity is set to a set value due to the non-linear characteristics of the arm in which the arm angular velocity increases at the end of the arm pulling. When it becomes larger than the above, the arm cylinder is automatically decelerated to decrease the arm angular velocity, so it is possible to prevent the deviation between the detected value of the bucket angle and the target value from becoming too large due to a sudden change in the arm angular velocity. Therefore, appropriate bucket constant angle control can be performed.

Further, since the actual arm angular velocity is detected, proper arm angular velocity control can always be performed without being affected by the load.

[Brief description of drawings]

FIG. 1 is a control block configuration diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram of an arm cylinder hydraulic control unit in the same embodiment, and FIG. 3 is an external view of a hydraulic excavator for performing slope excavation work. is there. 2 ... Boom, 3 ... Arm, 4 ... Bucket, 5 ...
Boom cylinder, 6 ... Arm cylinder, 7 ... Bucket cylinder, 8 ... Bucket angle sensor, 9 ... Arm angle sensor for obtaining arm angular velocity, C ... Controller C, 12 ... Bucket control amount calculation unit ( Bucket control means), 10 ... Bucket angle target value setting means, 13 ... Arm angle and speed calculation unit that constitutes arm control means, 14 ...
The arm control amount calculation unit, 11 ... Maximum arm angular velocity setting means, 15 ... Bucket cylinder hydraulic control unit, 16 ... Arm cylinder hydraulic control unit, 18 ... Operation valve that constitutes the control unit, 20 ... Same solenoid proportional valve, 21 ... Same switching valve.

Continuation of the front page (56) Reference JP-A-60-181429 (JP, A) JP-A-61-266740 (JP, A)

Claims (1)

[Claims] 1. A boom, an arm, a bucket, a boom cylinder for driving the boom, an arm cylinder for driving the arm, and a bucket cylinder for driving the bucket.
A bucket cylinder hydraulic control unit that controls the operation of the bucket cylinder, a bucket angle detection unit that detects the bucket angle, a bucket angle target value setting unit that sets a bucket angle target value, and a detection of these bucket angles. In a hydraulic shovel having a bucket control means for calculating and outputting a feedback control amount for the bucket cylinder hydraulic pressure control unit in accordance with a deviation between a value and a target value, an arm cylinder hydraulic pressure control for controlling the operation of the arm cylinder Section, the arm angular velocity detecting means for detecting the angular velocity of the arm, the maximum arm angular velocity setting means for setting the maximum value of the arm angular velocity, and the detected value of the arm angular velocity and the set value are compared, and the detected value is less than the set value. When it becomes large, the arm cylinder hydraulic control section decelerates the arm cylinder. Excavation control system for a hydraulic excavator, characterized in that the arm control means for sending a direction signal is provided.