JP2674918B2 - Hydraulic excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic excavator for excavating the ground, and more particularly to a hydraulic excavator for excavating while keeping the traveling direction of the bucket or the posture of the bucket constant.

[0002]

2. Description of the Related Art In front shovels of hydraulic excavators, there was a device for mechanically performing horizontal excavation (horizontal extrusion) using a master cylinder or the like, but it has a large number of parts and it is difficult to give an angle in the excavating direction. For some reason, it is not used as a backhoe. On the other hand, in the backhoe, a linear excavation device by electronic control has been proposed, but in all of them, a rotation angle sensor is attached to the nodal rotation part of the front linkage to control feedback. However, when using the angle sensor, it is necessary to calibrate the sensor for each mounting pin, and the mounting fixtures and covers for mounting the angle sensor on the joint pins require high accuracy and robustness. There was also such a problem. Further, in the feedback control of the cylinder, since the linkage is interposed between the cylinder and the angle sensor, the control calculation becomes complicated, which is one of the factors that deteriorate the control accuracy. Regarding hydraulic control, methods have been proposed to control the swash plate of the pump to adjust the cylinder speed, and to use a servo valve or pressure compensation valve to control the position of the cylinder as a hydraulic system that is not easily affected by the cylinder load. However, there was a drawback that the cost was high. In addition, there is a problem that the operation feeling during manual operation is greatly different from that of the conventional hydraulic system.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic excavator that can accurately and stably control the position and orientation of a bucket even if the accuracy and resolution of the sensor and the mounting accuracy of the sensor are not high. Is to do.

[0004]

A hydraulic excavator according to the present invention includes a hydraulic excavator main body, a boom having one end rotatably connected to the hydraulic excavator main body, and one end rotatably connected to the boom. One end of the stick is rotatably connected to the stick and one end is rotatably connected to the stick, and the other end is rotatably connected to the hydraulic excavator body. Is rotatably connected and the distance between the ends expands and contracts, and the boom hydraulic cylinder that rotates the boom relative to the excavator body, and one end rotatably connected to the boom and the other end rotates to the stick. A stick hydraulic cylinder that is connected and allows the distance between the ends to expand and contract to rotate the stick relative to the boom, and one end can rotate relative to the stick And a bucket hydraulic cylinder that rotatably connects the other end to the bucket and the distance between the ends expands and contracts to rotate the bucket with respect to the stick. A boom sensor that measures the telescopic displacement of the distance between the parts, a stick sensor that measures the telescopic displacement of the distance between the ends of the stick hydraulic cylinder, and a bucket that measures the telescopic displacement of the distance between the bucket and the end of the hydraulic cylinder. With a sensor, change the distance between the ends of the hydraulic cylinder until the measured telescopic displacement of the distance between the ends of the hydraulic cylinder equals the telescopic displacement of the distance between the ends of the desired hydraulic cylinder. Let

[0005]

According to the present invention, the hydraulic excavator has a boom sensor for measuring the telescopic displacement of the distance between the ends of the boom hydraulic cylinder, and a stick sensor for measuring the telescopic displacement of the distance between the ends of the stick hydraulic cylinder. , A bucket sensor for measuring the telescopic displacement of the distance between the ends of the bucket hydraulic cylinder, and the telescopic displacement of the measured distance between the ends of the hydraulic cylinder is Since the distance between the ends of the hydraulic cylinder is changed until it becomes equal to the expansion and contraction displacement, the boom rotation angle with respect to the hydraulic excavator body, the stick rotation angle with respect to the boom, and the bucket rotation angle with respect to the stick. The rotation angle is not controlled based on the actual rotation angle, but based on the measured telescopic displacement of the distance between the ends of each cylinder. It is. When controlling each cylinder based on the actual rotation angle, unless the accuracy and resolution of the angle sensor, the mounting accuracy of the sensor, and the accuracy of the mechanical dimensions measured in advance are high, the actual expansion and contraction displacement of each cylinder and the angle sensor The expansion and contraction displacement of each cylinder that is predicted based on the angle measured by does not correspond exactly, resulting in unnecessary cylinder displacement, and the expansion and contraction displacement of each cylinder cannot be accurately controlled. Furthermore, if the mechanism has low rigidity or the mechanism has a non-linear displacement element such as backlash, the control system is not stable and undesired vibration occurs.
Increasing the accuracy and resolution of the angle sensor and increasing the accuracy of sensor installation are generally more effective than increasing the accuracy and resolution of the linear sensor that measures the expansion and contraction displacement of the distance between the ends of the cylinder, and the accuracy of sensor installation. It is difficult, and it is generally difficult to increase the rigidity of the mechanism without increasing the weight of the mechanism and to keep the amount of non-linear displacement such as rattling of the mechanism low while maintaining durability and low sliding resistance. The advantages of the present invention over the prior art are even more significant.

When controlling each hydraulic cylinder of a hydraulic excavator, if control is performed based on the measured expansion and contraction displacement of the distance between the end portions of each cylinder, each cylinder can be controlled even if the accuracy and resolution of the sensor and the mounting accuracy are low. The distance between the ends of the cylinder can be controlled accurately, and the operation of each cylinder is stable even if the mechanism has low rigidity or the mechanism has a non-linear displacement element such as backlash.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the system according to the present invention, a pressure sensor 19 and a pressure switch 16 are installed in a conventional pilot hydraulic line to detect the operation amounts of operating levers 6 and 8 to detect cylinder displacement, speed and acceleration sensors 20, 21 and 22.
Is used to perform feedback control, and the control is independent multi-degree-of-freedom feedback control for each cylinder 120, 121, 122. (Addition of an oil device such as a pressure compensation valve is unnecessary.) The vehicle body 1 using the vehicle inclination angle sensor 24
The influence of the tilt of 00 is corrected, and the solenoid proportional valve 3 is used to drive the cylinders 120, 121, 122 by the electric signal from the controller 1. The manual / semi-automatic mode changeover switch allows the operator to arbitrarily select a mode. A setting device for setting the target slope angle is provided. The pressure sensor 19 is attached to the pilot pipe connected to the main control valves 13, 14 and 15 from the expansion and contraction of the stick 300 and the upper and lower operation levers 6 and 8 of the boom 200. This pilot hydraulic pressure is applied to the operating levers 6,
Since it changes depending on the operation amount of 8, the operation amount of the operation levers 6 and 8 can be estimated by measuring this hydraulic pressure. The stick operation lever 8 is used to determine the bucket tooth tip moving speed in the direction parallel to the set excavation slope, and the boom operation lever 6 is used to determine the bucket tip moving speed in the direction perpendicular to the set slope. Therefore, when the stick operation lever 8 and the boom operation lever 6 are simultaneously operated, the moving direction and speed of the bucket tooth tip are determined by the combined vector parallel and vertical to the set slope.

The pressure switch 16 is attached to the pilot pipes of the operating levers 6 and 8 for the boom, stick and bucket via a selector 17. This pressure switch 1
6 is used to detect whether the operation levers 6 and 8 are neutral. That is, when the operation levers 6 and 8 are in the neutral state, the output of the pressure switch is OFF, and the operation levers 6 and 8 are
When 8 is used, the output of the pressure switch is turned on. The neutral detection pressure switch 16 is used for detecting an abnormality of the pressure sensor 19 and for switching a manual / semi-automatic mode.

Cylinder displacement, velocity and acceleration sensor 2
0, 21, 22 are attached to each cylinder and used for feedback control, and the displacement signal is also used for measuring coordinates for position measurement / display of bucket tip. The bucket tip position in the semi-automatic system is calculated with one point on the upper revolving superstructure 1 of the hydraulic excavator as the origin, but when the upper revolving superstructure 1 is tilted in the front linkage direction, the coordinate system in the control calculation is divided by the vehicle tilt. Only need to rotate. The tilt sensor 24 is used to correct the rotation amount of this coordinate system.

The electromagnetic proportional valve 3 controls the hydraulic pressure supplied from the pilot pump 50 by an electric signal from the controller 1, and the main control valves 13, 14, 15 are controlled so that the target speeds of the cylinders 120, 121, 122 are obtained. Control spool position. The controlled hydraulic pressure is transmitted to the main control valves 13, 14, 15 through the switching valve 4 or the selector valve 18.
The cylinder can be manually controlled by setting the switching valve 4 to the manual mode side. The boom and stick merging adjustment proportional valves 11 and 12 adjust the merging degree of the two pumps 51 and 52 in order to obtain the oil amount according to the target cylinder speed.

The stick operation lever 8 is ON-OFF
A switch (slope excavation switch) 9 is attached,
The operator operates this switch to select or deselect the semi-automatic mode. When the semi-automatic mode is selected, the bucket tip can be moved linearly. An ON-OFF switch (bucket automatic return start switch) 7 is attached to the bucket operation lever 6, and when the driver turns on this switch, the bucket automatically returns to a preset corner.

The safety valve 5 is for interrupting the pilot pressure supplied to the proportional valve 3, and the pilot pressure is supplied to the solenoid proportional valve 3 only when the safety valve 5 is in the ON state. Therefore, if some failure occurs in the semi-automatic control, or if a dangerous state can occur, the safety valve can be turned off to promptly stop the automatic control of the linkage.

The rotation speed of the engine depends on the position of the engine throttle set by the operator. Further, even if the engine throttle is constant, the engine speed changes depending on the load. Since the pumps 50, 51, 52 are directly connected to the engine, when the engine speed changes, the pump discharge amount also changes, so the main control valves 13, 1
Even if the spool positions of 4 and 15 are constant, the cylinder speed changes according to the change of the engine rotation speed.
An engine speed sensor 23 is attached to correct this. That is, when the engine rotation speed is low, the target moving speed of the bucket tip is slowed.

Monitor panel 10 with target slope setting device
(Hereinafter referred to as the monitor panel) is used as a setter for the target slope angle and the bucket return angle, as well as an indicator for the coordinates of the bucket tooth tips, the measured slope angle, and the measured distance between two point coordinates. Also used.

Compared with the conventional manual control system, the system according to the present invention adds the following semi-automatic control function. The pressure sensor 19 is used to determine the operation amount of the operation levers 7 and 8 based on the change in pilot pressure. The conventional open center valve hydraulic system is used as it is. The bucket tip coordinates are displayed in real time on the monitor with target slope angle setting device 10 (which does not require addition of a pressure compensation valve or the like). Measure the excavation depth and distance. Measure the shaped slope angle. Linkage 200, 300, 400
Cylinder displacement, speed and acceleration sensors 20, 21 and 22 are used as the movement amount sensor. (An angle sensor is not used for the pin joint part.) Main control valve 1
The spools 3, 14 and 15 are controlled using the solenoid proportional valve 3. Feedback control loop for each cylinder 1
It is independent for each 20, 121, 122. The control algorithm is multi-free control of displacement, velocity, acceleration and feedforward. The use of the safety valve 5 prevents runaway when the system is abnormal. Boom 2
The combined movement amount of 00 and the stick 300 is an electronic hydraulic system that is automatically adjusted according to the excavation speed. The control accuracy is improved by linearizing the non-linearity of hydraulic equipment at high speed using a table lookup method. Even in the semi-automatic excavation mode, the bucket angle and the target slope height can be finely adjusted manually (during excavation). There is a function of automatically returning the bucket 400 to a preset bucket angle (automatic bucket return). You can perform maintenance such as gain adjustment using an external terminal. The influence of the vehicle inclination is corrected by the vehicle inclination sensor 24.
By reading the engine rotation speed, the deterioration of control accuracy due to engine throttle position and load fluctuations is corrected.

The semi-automatic system has a semi-automatic control mode, a manual mode and a service mode. Each mode will be described below. 1. Semi-automatic control mode (1) Bucket angle control mode A mode in which the angle (bucket angle) with respect to the horizontal direction (vertical direction) of the bucket 400 is always kept constant even if the stick 30 and the boom 200 are moved (bucket angle on the monitor panel 10). Control switch ON). When the bucket 400 is manually moved, this mode is released and the bucket angle at the time when the bucket stopped is stored as a new bucket holding angle. (2) Slope excavation mode A mode in which the tip 12 of the bucket 400 moves linearly. However, the bucket cylinder 122 does not move. (The bucket angle changes with the movement of the bucket.) (Fig. 2) (3) Slope excavation mode + bucket angle control mode A mode in which the tip 12 of the bucket 400 moves linearly. The bucket angle is also kept constant during excavation. (Fig. 3) (4) Bucket automatic return mode This mode automatically returns the bucket angle to a preset angle. The return bucket angle is set by the monitor panel 10. This mode starts when the bucket automatic return start switch 7 on the bucket operation lever 6 is turned on. This mode is released when the bucket 400 returns to a preset angle.

In the above (2) and (3), the semi-automatic control switch on the monitor panel 10 and the slope excavation switch 9 on the stick operating lever 8 are turned on, and both the stick operating lever 8 and the boom operating lever 6 are turned on. Or enter these modes when either is moved. The target slope angle is set by operating a switch on the monitor panel 10. In these modes, the operation amount of the stick operation lever 8 gives the bucket tooth tip moving speed in the direction parallel to the target slope angle, and the operation amount of the boom operation lever 6 gives the bucket tooth tip moving speed in the vertical direction. Therefore, when the stick operation lever 8 is moved, the bucket tooth tip 112 starts to move linearly along the target slope angle, and by moving the boom operation lever 6 during excavation, fine adjustment of the target slope height can be performed manually. Become. Further, in these modes, by operating the bucket operating lever 6, the bucket angle during excavation can be finely adjusted, and the target slope height can also be changed.

2. Manual mode Modes other than the semi-automatic control mode described in 1 above. In this mode, the operation similar to that of the conventional hydraulic excavator can be performed, and the coordinates of the bucket tooth tip 112 can be displayed.

3. Service mode Mode for performing service and maintenance of the entire semi-automatic system. This mode is performed by connecting the external terminal 2 to the controller 1. The control gain is adjusted and each sensor is initialized depending on the service mode. Operation of each mode and switches 7, 9, 16
Table 1 shows the states of the electromagnetic proportional valve 3, the switching valve 4, and the safety valve 5.

[0020]

[Table 1] ○: ON ×: OFF −: ON or OFF

Next, a method of setting the target slope angle and the return angle in the semi-automatic system will be described. 1. Target slope angle setting method: The target slope angle is set by the following three methods. (1) A method of inputting a numerical value by a switch on the monitor panel 10: A method of numerically inputting a target slope angle in degrees or%, and both positive and negative values can be input. (2) Two-point coordinate input method: A method in which the coordinates of the bucket tip are measured at two points and the target slope angle is calculated from the inclination of the two points. Specifically, the operator moves the bucket tip 112 to two positions, a lower part and an upper part of the excavation slope, and obtains the target slope angle by measuring the respective coordinates. The target slope angle θ is calculated by the following equation.

[0022]

(Equation 1) θ = target slope angle X ₁ , Y ₁ : X and Y coordinates of the bucket tip of the first point X ₂ , Y ₂ : X and Y coordinates of the bucket tip of the second point

(3) Input method by bucket angle: The bucket 400 is moved until the target slope setting angle is reached, and the bucket angle at that time is stored by a switch operation on the monitor panel 10. This angle is the target slope setting angle. The bucket angle is displayed in real time on the monitor panel 10 while the bucket 400 is being moved.

2. Setting method of bucket return angle The target bucket return angle in the bucket automatic return mode is set by the following two methods. (1) Method by inputting a numerical value using the switch on the monitor panel: Input the target bucket return angle numerically. (2) Method by moving bucket: The bucket 400 is moved until the bucket angle reaches the target bucket return angle, and the bucket angle at that time is stored by a switch operation on the monitor panel 10. This angle is the target bucket return angle. The bucket angle is displayed in real time on the monitor panel 10 while the bucket 400 is being moved.

Next, the control algorithm of the semi-automatic system will be described. A semi-automatic control mode (excluding bucket automatic return mode) control algorithm is shown in FIG. First, the moving speed and direction of the bucket tip 112 are obtained from the information of the target slope setting angle, the pilot hydraulic pressure for controlling the stick cylinder 121 and the boom cylinder 120, the vehicle inclination angle, and the engine rotation speed. Next, the target speed of each cylinder 120, 121, 122 is calculated based on the information. At this time, information on the engine speed is necessary when determining the upper limit of the cylinder speed. Control each cylinder 12
An independent feedback loop is provided for each of 0, 121 and 122, and they do not interfere with each other. As shown in FIG. 5, the compensator in the closed loop control has a multi-degree-of-freedom configuration of a feedback loop and a feedforward loop of three systems of displacement, velocity and acceleration. In particular, the feedback loop inside the velocity and acceleration is useful for compensating the cylinder velocity due to linkage attitude changes and load fluctuations. The acceleration signal may be obtained by differentiating the velocity signal in the controller. The non-linearity removal table is for removing non-linearity of the solenoid proportional valve, the main control valve, etc., and can be processed at high speed by the microcomputer by using the table lookup method.

Each semi-automatic control mode and its control method are shown below. Figure 6 shows the front linkage. L is a fixed length A is a fixed angle λ is a variable length of the cylinder length θ is a variable angle.
For example, L ₁₀₁₁₀₄ is the distance between the nodes 101 and 104, λ
₁₀₂₁₁₁ is the length of the boom cylinder 120, A _102101104
Is the angle between L ₁₀₁₁₀₂ and L ₁₀₁₁₀₄ , and θ _102101111 is L
_The angle formed by ₁₀₁₁₀₂ and L ₁₀₁₁₁₁ is shown. Note that the node 101 is x
The origin of the y coordinate.

1. Bucket Angle Control Mode The length of the bucket cylinder 122 is controlled so that the angle φ formed between the bucket 400 and the x axis is constant at any position. Bucket cylinder length λ ₁₀₆₁₀₉ is boom cylinder length λ ₁₀₂₁₁₁ , stick cylinder length λ ₁₀₃₁₀₅ and φ
Is required when is decided. λ ₁₀₂₁₁₁ and λ ₁₀₃₁₀₅ are obtained in real time by the sensors 20 and 21. Therefore, the target value of λ ₁₀₆₁₀₉ is also calculated in real time, and the bucket cylinder 12 is made to follow this target value.
2 is controlled. Bucket cylinder length λ ₁₀₆₁₀₉ is _calculated by the following formula.

[0028]

(Equation 2)

## _EQU3 ## θ _106107109 = 2π-A _104107106 -A _104107108 -θ _109107108

(4) θ _109107108 = θ _109107110 + θ _108107110

(Equation 5)

(Equation 6)

(Equation 7)

[Equation 8] _{θ 107108110 = 2π-A 110108112 -φ} + θ bm + θ st

## _EQU9 ## θ _bm = θ _102101111 -A _102101104 -A _xbm101111

(Equation 10)

[Equation 11]

2. Slope excavation mode + bucket angle control mode Bucket angle is kept constant, so bucket tip position 1
12 and the node 108 move in parallel. First, consider the case where the node 108 moves parallel to the x-axis (horizontal excavation). Node 108 in the linkage attitude for starting excavation
Let (x ₁₀₈ , y ₁₀₈ ) be the coordinates of. At this time, the cylinder lengths of the boom cylinder 120 and the stick cylinder 121 in the linkage posture may be calculated, and the speeds of the boom 200 and the stick 300 may be calculated so that x ₁₀₈ moves horizontally. The moving speed of the node 108 is determined by the operation amount of the stick operation lever 8. Node 10
Boom cylinder length λ ₁₀₂₁₁₁ , stick cylinder length λ, given 8 coordinates (x ₁₀₈ , y ₁₀₈ ).
₁₀₃₁₀₅ is obtained as follows.

[0030]

(Equation 12)

[ _Equation 13] θ _102101111 = θ _bm + A _xbm101111

[Equation 14]

(Equation 15)

(Equation 16)

[Equation 17]

[ _Equation 18] θ _103104105 = 2π−A _101104103 −A _105104108 −θ _101104108

[Equation 19]

When the parallel movement of the node 108 is considered by the microcomputer, the coordinate of the node 108 after the minute time Δt is (x ₁₀₈ +
Δx, y ₁₀₈ ). Δx is a minute displacement determined by the moving speed. Therefore, the target boom and stick cylinder lengths after Δt can be obtained by substituting x ₁₀₈ + Δx instead of x _{108 in} the above equation. The target cylinder speed can be obtained by differentiating the target cylinder length. The differential in microcomputer processing is calculated by the following equation. Ie

(Equation 20) Of course, the target cylinder velocity is obtained by differentiating the x coordinate of the node 108. May be calculated first. Control of the bucket angle can be obtained by the method described in 1 above, but the boom cylinder length λ
_{For 102111} and stick cylinder length λ _103105, accuracy is improved by using the target cylinder length after Δt seconds instead of using the current length.

3. Slope excavation mode The slope excavation mode is obtained in the same manner as in the above-mentioned item 2, but the moving point is changed from the node 108 to the bucket tip position 112, and the bucket cylinder length is fixed. Therefore, (x ₁₀₈ , y ₁₀₈ ) used in the above 2 is converted to (x ₁₁₂ , y ₁₁₂ ) by L
₁₀₄₁₀₈ may be _replaced with λ ₁₀₄₁₁₂ and A _105104108 may be replaced with θ _105104112 . λ ₁₀₄₁₁₂ and θ _{105 104112} are obtained as follows.

[0033]

(Equation 21)

[ _Equation 22] θ _104108112 = 2π−A _110108112 −A _104108107 −θ _107108110

(23) θ _107108110 = θ _107108109 + θ _109108110

(Equation 24)

(Equation 25)

(Equation 26)

[ _Equation 27] θ _109107108 = 2π−A _104107108 −A _104107106 −θ _106107109

[Equation 28] λ ₁₀₆₁₀₉ : Bucket cylinder length

(Equation 29)

When the slope angle α ≠ 0 (when excavating a slope) θ
_{By replacing bm} with θ _bm + α, the bucket tooth tip moves on the straight line having the inclination of the angle α. That is, it is equivalent to converting the xy coordinates in FIG. 6 into x′y ′ coordinates. However, the x′y ′ coordinates are obtained by rotating the xy coordinates by α around the origin. When the bucket operation lever is moved during the slope excavation mode, the bucket tip 112,
When the boom operation lever 6 is moved, the y coordinates of the bucket tip 112 and the node 108 change. Therefore, by manually updating the target bucket tip coordinates or the coordinates of the node 108 regardless of changes in these y coordinates, manual fine adjustment becomes possible. The control of each cylinder is feedback-controlled so as to follow the target cylinder length and speed.

1. Compensation of finishing inclination angle by vehicle inclination sensor The calculation of the front linkage position is performed by node 10 in FIG.
It is performed in the xy coordinate system with 1 as the origin. Therefore, when the vehicle body tilts with respect to the xy plane, the xy coordinates rotate, and the target tilt angle with respect to the ground changes. To correct this, a tilt angle sensor is attached to the vehicle to detect the rotation angle of the vehicle body in xy coordinates. That is, when it is detected by the tilt angle sensor that the vehicle body is rotated by β with respect to the xy plane, θ _bm is _replaced with θ _bm + β in the same manner as when the slope angle α is set. Can be corrected by

2. Prevention of deterioration of control accuracy by the engine speed sensor (1) Correction of target bucket tip speed The target bucket tip speed is determined by the position of the stick and boom operating levers 6 and 8 and the engine speed. Since the hydraulic pumps 51 and 52 are directly connected to the engine, the pump discharge amount also decreases when the engine speed is low, and the cylinder speed also decreases. Therefore, the target bucket tip speed is calculated so as to detect the engine rotation speed and match the change in the pump discharge amount. That is, when the engine rotation speed is V _e , the target bucket tip speeds V _x and V _y are obtained as follows. However, V _x indicates the bucket tip speed in the x direction, and V _y indicates the bucket tip speed in the y direction.

[0037]

V _x = C _x · V _e · P _x

[Formula 31] V _y = C _y · V _e · P _y C _x : constant of target bucket tooth tip speed in x direction C _y : 〃 y 〃 P _x : operation amount of stick operation lever (pilot hydraulic pressure) P _y : Boom 〃

(2) Correction of maximum value of target cylinder speed The target cylinder speed changes depending on the attitude of the linkage and the target slope inclination angle. In this case, since the maximum value of the target cylinder speed is determined by the pump discharge amount, if the pump discharge amount decreases as the engine speed decreases, the maximum cylinder speed also needs to decrease. That is, the maximum cylinder speed is calculated by the following equation.

V _cmaxjj = V _cmaxojj · V _emax / V _e V _cmaxjj : Maximum cylinder speed V _cmaxojj : Maximum cylinder speed at rated engine speed V _emax : Rated engine speed V _e : Current engine speed, however jj Represents each cylinder. That is, jj = bm: boom cylinder jj = st: stick cylinder jj = bk: bucket cylinder When the calculated target cylinder speed exceeds the maximum cylinder speed, the target bucket tooth tip speed is reduced and the target cylinder speed is the maximum cylinder speed. It is recalculated so as not to exceed the speed.

[0039]

According to the present invention, linear excavation in a hydraulic excavator can be performed by operating one operating lever, the bucket angle can be kept constant regardless of the position of the boom stick, and the bucket can be removed from the bucket during loading work. It is possible to prevent spillage of cargo, add semi-automatic control while making full use of the functions of conventional manual operation, can monitor bucket tooth tip position, measure excavation depth and distance, and have a shaped slope. The angle of can be measured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a control system according to the present invention.

FIG. 2 is a schematic view showing the operation of the hydraulic excavator according to the present invention.

FIG. 3 is a schematic view showing the operation of the hydraulic excavator according to the present invention.

FIG. 4 is a diagram showing a functional configuration of a control system according to the present invention.

FIG. 5 is a schematic diagram showing a feedback system of the control system according to the present invention.

FIG. 6 is a schematic view of an operating portion of the hydraulic excavator according to the present invention.

[Explanation of symbols]

1 Controller 2 External Terminal 3 Electromagnetic Proportional Valve 4 Electromagnetic Switching Valve 5 Safety Valve 6 Boom and Bucket Operating Lever 7 Bucket Automatic Return Start Switch 8 Stick Operating Lever 9 Slope Excavation Switch 10 Monitor Panel with Target Slope Angle Setting Device 11 Stick Join Proportion Valve 12 Boom confluence proportional valve 13 Boom main control valve 14 Stick main control valve 15 Bucket main control valve 16 Pressure switch 17 Selector valve (for operating lever) 18 Selector valve (for manual / semi-automatic mode) 19 Pressure sensor 20 Boom cylinder position / Speed / acceleration sensor 21 Stick cylinder position / speed / acceleration sensor 22 Bucket cylinder position / speed / acceleration sensor 23 Engine speed sensor 24 Tilt angle sensor 120 Boom cylinder 121 Stick series Dah 122 bucket cylinder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Tozawa 1-3-2 Kita-Aoyama, Minato-ku, Tokyo Inside New Caterpillar Mitsubishi Corporation (72) Inventor Satoshi Fujii 1-3-2 Kita-Aoyama, Minato-ku, Tokyo New Caterpillar Mitsubishi Corp. (72) Inventor Tomoaki Ono 1-32 Kita-Aoyama, Minato-ku, Tokyo New Caterpillar Mitsubishi Corp. (56) Reference JP-A-6-200537 (JP, A) JP Flat 5-280067 (JP, A) Actual Open Flat 6-24052 (JP, U)

Claims (9)

(57) [Claims] 1. A hydraulic excavator, including a hydraulic excavator body, a boom whose one end is rotatably connected to the hydraulic excavator body, a stick whose one end is rotatably connected to the boom, and a stick. On the other hand, one end is rotatably connected, the tip is excavated on the ground and the inside can store soil, and the one end is rotatably connected to the excavator body,
The other end is rotatably connected to the boom, and the distance between the ends expands and contracts to rotate the boom with respect to the hydraulic excavator body. The boom hydraulic cylinder and one end are rotatably connected to the boom. The other end is rotatably connected to the stick, the distance between the ends expands and contracts, and the stick rotates with respect to the boom.
One end of the stick hydraulic cylinder is rotatably connected to the stick, the other end is rotatably connected to the bucket, and the distance between the ends expands and contracts to rotate the bucket with respect to the stick. Bucket hydraulic cylinder, boom sensor to measure the telescopic displacement of the distance between the ends of the boom hydraulic cylinder, stick sensor to measure the telescopic displacement of the distance between the ends of the stick hydraulic cylinder, and the end of the bucket and hydraulic cylinder And a bucket sensor that measures the telescopic displacement of the distance between, until the measured telescopic displacement of the distance between the ends of the hydraulic cylinder becomes equal to the telescopic displacement of the distance between the desired ends of the hydraulic cylinder. , Hydraulic excavators that change the distance between the ends of hydraulic cylinders. 2. The hydraulic excavator according to claim 1, wherein the angle of the bucket with respect to the horizontal direction is kept constant,
A hydraulic excavator where the tip of the bucket excavates the ground. 3. The hydraulic excavator according to claim 1, wherein the tip of the bucket moves along a straight line forming an angle with the horizontal direction to excavate the ground. 4. The hydraulic excavator according to claim 1, wherein the bucket tip excavates the ground while keeping the moving speed of the bucket tip constant. 5. The hydraulic excavator according to claim 1, wherein the rate of change of the distance between the ends of the hydraulic cylinder is controlled to determine the amount of expansion / contraction displacement of the distance between the ends of the hydraulic cylinder. 6. The hydraulic excavator according to claim 1, wherein in determining the expansion / contraction displacement amount of the distance between the ends of the hydraulic cylinder, the acceleration of change in the distance between the ends of the hydraulic cylinder is controlled. . 7. The hydraulic excavator according to claim 1, further comprising an inclination sensor for measuring an inclination angle of the hydraulic excavator main body with respect to a horizontal direction, and an end of the hydraulic cylinder according to the inclination angle measured by the inclination sensor. A hydraulic excavator that adjusts the amount of expansion and contraction displacement of the distance between parts. 8. The hydraulic excavator according to claim 1, further comprising an output rotation speed sensor for generating an oil pressure for driving a hydraulic cylinder using an internal combustion engine as a power source and measuring an output rotation speed of the internal combustion engine. A hydraulic excavator that adjusts the changing speed of the distance between the ends of the hydraulic cylinder according to the output speed measured by a number sensor. 9. The hydraulic excavator according to claim 2, wherein the bucket keeps a constant angle with respect to the horizontal direction,
As the tip of the bucket digs the ground, depending on the measured telescopic displacement of the distance between the ends of the boom hydraulic cylinder and the measured telescopic displacement of the distance between the ends of the stick hydraulic cylinder, the bucket hydraulic cylinder A hydraulic excavator that controls the expansion and contraction displacement of the distance between the ends of the.