JPH0680252B2 - Excavation control device for hydraulic excavator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic excavator such as a hydraulic excavator, a loader excavator, a tractor excavator, and the like, and relates to an excavation control device for a hydraulic excavator that controls a trajectory of the excavation. .

[Conventional technology]

When excavating using a hydraulic excavator, it is often required that the excavation surface be a specific surface, such as a horizontal surface or a surface having a certain inclination. In such a case, it is necessary to drive the tip of the excavation portion so as to draw a predetermined trajectory. This will be described with reference to FIG.

FIG. 3 is a side view of the hydraulic shovel. In the figure, 1 is a lower traveling body, 2 is an upper swing body, 3 is a boom rotatably attached to the upper swing body 2, 4 is an arm rotatably attached to the boom 3, and 5 is an arm 4. A bucket rotatably attached, 6 is a boom cylinder for driving the boom 3, 7 is an arm cylinder for driving the arm 4, and 8 is a bucket cylinder for driving the bucket 5. 9 is a boom angle detector that detects a relative angle between the upper swing body 2 and the boom 3, 10 is an arm angle detector that detects a relative angle between the boom 3 and the arm 4, and 11 is a relative angle between the arm 4 and the bucket 5. It is a boom angle detector that detects an angle. Incidentally, D indicates the tip of the bucket 5.

Now, in the excavation work of the hydraulic shovel, it is assumed that it is necessary to excavate in a plane having an inclination of an angle φ with respect to the ground as shown by a dashed line in the figure. In order to perform such excavation, the angular velocity of the boom 3 and the angular velocity of the arm 4 must be driven at predetermined angular velocities, and depending on the operation of the boom lever and the arm lever by the operator, such driving is required. Is extremely difficult. Therefore, conventionally, a required flow rate for the boom cylinder 6 and the arm cylinder 7 is calculated by the microcomputer based on the detection values of the boom angle detector 9, the arm angle detector 10, etc., and the boom 3 and the arm 4 are driven by this. The means to do is adopted.

In such a means, in order to obtain a high excavation speed, the upper limit value of the flow rate to be supplied to the boom cylinder 6 and the arm cylinder 7 is set in advance according to the condition of the hydraulic circuit for driving the boom cylinder 6 and the arm cylinder 7, and within the range of the upper limit value. , A method of largely setting the target value of the flow rate was adopted.

[Problems to be Solved by the Invention]

By the way, the above-mentioned conventional method is theoretically possible, but in reality, there is a mechanical operation delay of each element in the hydraulic circuit, and the hydraulic circuit has hysteresis characteristics (characteristics when the flow rate increases and decreases). Therefore, the boom 3 and the arm 4 cannot be driven at a speed according to the target value. As a result, a speed component in a direction perpendicular to the target trajectory is generated, and the tip D of the bucket 5 is There was a problem that it deviated from the target trajectory. Then, in order to avoid such a problem, the upper limit value of the flow rate is inevitably set to a small value, which causes a problem that a high excavation speed cannot be obtained.

The object of the present invention is to solve the above-mentioned problems in the conventional technology,
An object of the present invention is to provide an excavation control device for a hydraulic excavator, which can excavate a predetermined trajectory at a large speed and improve work efficiency.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a boom driven by a boom cylinder, an arm driven by an arm cylinder, and a hydraulic circuit for driving the boom and the arm. In a provided hydraulic excavator, a boom angle detector that detects the angle of the boom, an arm angle detector that detects the angle of the arm, and a boom at a certain arm angle determined from the structure of the hydraulic excavator. Storage means for storing the maximum drive speed of the cylinder and the maximum drive speed of the arm cylinder for each arm angle, and the arm angle detected by the arm angle detector based on the maximum drive speed stored in the storage means. A first calculation means for calculating the maximum angular velocity of the boom and the maximum angular velocity of the arm, and the boom angle detector and the arm. A second calculation means for obtaining a command value for the boom angular velocity and a command value for the arm angular velocity required to carry out excavation in a predetermined manner corresponding to the detection value of the arm angle detector; and the first calculation means. Comparing means for comparing each obtained maximum angular velocity with the corresponding angular command value determined by the second computing means, and as a result of comparison by this comparing means, only one command value is equal to or greater than the corresponding maximum angular velocity. When this maximum angular velocity is a new command value,
When both command values are greater than or equal to the corresponding maximum angular velocities, the command value correction means for setting the maximum angular velocity having the larger difference between the command values and the maximum angular velocity as the corresponding new command value, and the command value correction means Is corrected, the third command means for correcting the other command value so as to maintain the ratio of the two command values obtained by the second calculation means.

[Operation] In the storage means, the maximum drive speeds of the boom cylinder and the arm cylinder at a certain arm angle, which are determined by the mechanical configuration of the hydraulic excavator used and the hydraulic circuit, are stored in advance for each arm angle. . In the excavation work, first, the maximum driving speeds for the current arm angle are read from the storage means, and the maximum angular speeds of the boom and the arm are calculated by the first computing means based on the read maximum driving speeds. Further, the second computing means obtains a boom angular velocity command value and an arm angular velocity command value for obtaining a required excavation locus based on the boom angle and the arm angle. Compare the calculated boom angular velocity command value with the maximum boom velocity, and compare the calculated arm angular velocity command value with the maximum arm velocity.If the boom angular velocity command value is equal to or greater than the boom maximum angular velocity, The maximum angular velocity of the boom is set as the new boom angular velocity command value, and when the arm angular velocity command value is greater than or equal to the maximum angular velocity of the arm, the maximum angular velocity of the arm is set as the new arm angular velocity command value. If both the command value and the arm angular velocity command value are equal to or greater than the boom maximum angular velocity and arm maximum angular velocity, respectively, the maximum increment corresponding to the maximum angular velocity (the difference between the maximum angular velocity and the command value) is the corresponding maximum. Set the angular velocity as a new set value. Next, the third computing means calculates a command value that has not been set to the maximum angular velocity, and the ratio of the command value to the set maximum angular velocity is the second.
The new command value is changed so as to be equal to the ratio of the two command values obtained by the calculating means. The two new command values thus obtained control the boom angular velocity and the arm angular velocity.

〔Example〕

 Hereinafter, the present invention will be described based on the illustrated embodiments.

FIG. 1 is a system diagram of an excavation control device for a hydraulic shovel according to an embodiment of the present invention. In the figure, the same parts as those shown in FIG. Reference numeral 15 is a hydraulic pump mounted on the hydraulic shovel, 16 is an electromagnetic control valve interposed between the hydraulic pump 15 and the boom cylinder 6 to control the drive of the boom cylinder, 17 is a hydraulic pump 15 and the arm cylinder 7. It is an electromagnetic control valve that controls the drive of the arm cylinder by being interposed therebetween. 18 is an excavation speed setting device that determines an arbitrary excavation speed, and 19 is an excavation gradient setting device that sets an angle φ between the horizontal plane and the excavation surface.

Reference numeral 20 denotes a control device for controlling excavation, which includes an input unit 20a and a calculation unit.
20b, a storage unit 20c, and an output unit 20d. A micro computer is used for the control device 20, and the calculation unit 20b performs calculation and control necessary for obtaining the required boom angular velocity and arm angular velocity. Also, storage
The storage unit 20c stores the calculation and control procedures of the calculation unit 20b, stores the input values and the calculation results, and further stores the values described below.

The boom cylinder and arm cylinder of the hydraulic excavator are no longer driven by the supply of pressure oil from the hydraulic pump when the arm is at an angle. Therefore, in this state, the boom cylinder and the arm cylinder cannot be accelerated by the flow rate supplied from the hydraulic pump, and cannot be driven at a speed higher than a certain drive speed (maximum drive speed).

For example, consider a case where the bucket is pulled forward from a state in which the arm is further extended (the state in which the arm cylinder is further contracted) than the state shown in FIG. 3 to perform horizontal excavation.
In this case, the arm is first driven in the winding direction (direction in which the arm cylinder extends). At this time, the arm is driven by the return oil from the arm cylinder rod side due to the action of gravity. The drive speed is determined by the meter-out flow rate characteristic for the return oil, and the flow rate characteristic is determined by the arm angle, the arm weight (including bucket weight, the same applies below), and the structure of the directional control valve spool. . That is, the maximum drive speed in this case is determined by the arm angle, the weight of the arm, and the structure of the directional control valve spool.

Furthermore, considering the state of the boom in this case, when the winding of the arm progresses and the angle of the arm exceeds a certain angle, the boom cylinder switches from extension to contraction, and thereafter, the boom is moved by the action of gravity to the head of the boom cylinder. It is driven by the return oil from the side, and its driving speed is determined by the flow rate characteristic of meter-out, and the flow rate characteristic is determined by the arm angle, the weight of the boom and the arm, and the structure of the spool of the directional control valve.

Thus, the maximum drive speed is not determined only by the flow rate of the pressure oil supplied from the hydraulic pump, but the boom, arm weight, hydraulic circuit (the structure of the directional control valve spool), etc., depending on the arm angle during excavation. , It may be determined from the structure of the hydraulic excavator.

In the present embodiment, in consideration of the above phenomenon, in the storage unit 20c,
Maximum boom cylinder drive speed v for each arm angle
_βmax and the maximum driving speed v _αmax of the arm cylinder are stored.

Next, the operation of this embodiment will be described with reference to the flow chart shown in FIG. First, the controller 20 includes a boom angle detector 9, an arm angle detector 10, and a bucket angle detector.
The detected values β, α, γ detected in 11 and the set values v, φ set in the excavation speed setter 18 and the excavation gradient setter 19 are respectively input via the input unit 20a (steps S ₁ ~ S ₅ ). Then, based on the arm angles α which is detected, the maximum driving speed v _.alpha.max maximum drive speed v _.beta.max and the arm cylinder 7, the boom cylinder 6 is read from the storage unit 20c (Step S _6, S _7). The arithmetic unit 20b, the arm when the boom angular velocity _max when the boom cylinder 6 is driven at the maximum drive speed v _.beta.max (maximum boom angular velocity), and the arm cylinder 7 is driven at the maximum drive speed v _.alpha.max angular _max (Maximum arm angular velocity) is calculated.

Then, the respective values β, α, input in steps S _{1 to} S ₅ ,
gamma, v, based on the phi, calculates the boom angular speed ₀ and the arm angular velocity ₀ required to perform the drilling line trajectory of the third angle as shown in FIG phi (Step S ₁₀ ~S _11). That is, to perform the drilling boom 3 and the arm 4 at the same time each angular velocity _{0, 0,} or the ratio of the respective angular velocities must drive to be equal to the value _0/0. Here, the calculated boom angular velocity ₀ and
Comparing the maximum boom angular speed _max obtained previously (Step S _12).

As a result of the comparison in step S ₁₂ , when the boom angular velocity ₀ is less than the maximum boom angular velocity _max , this time the arm angular velocity is reached.
₀ and comparing the maximum arm velocity _max (Step S _13).
In this procedure, the arm angular velocity ₀ is the maximum arm angular velocity.
When it is determined to be less than the _max, i.e., none of the boom angular speed ₀ and the arm angular velocity _0, the maximum boom angular speed _max, when it is less than the maximum arm angular speed _max, they boom angular velocity _0, the arm angular velocity ₀ as , Angular velocity signal for controlling each solenoid control valve 16, 17
_{1, 1} (Step S ₁₄ to S _15), and outputs to the output section 20d (Step S _16).

On the other hand, in step S ₁₃ , the arm angular velocity ₀ is the maximum arm angular velocity.
_When it is determined that it is equal to or greater than _max , that is, when the boom angular velocity ₀ is less than the maximum boom angular velocity _max and the arm angular velocity ₀ is equal to or greater than the maximum arm angular velocity _max ,
An arm angular velocity ₁ to be output to the output section 20d as the maximum arm velocity _max (Step S _17), whereas, the arm angular speed
Boom angular velocity to be output based on ₁ (= _max )
Calculate ₁ This operation is the ratio of the boom angular and arm velocity to be output _(1/1) the ratio of the aforementioned ₍₀ /
₀ ) because it must equal The sought (Step S _18). As a result, the boom 3 has a maximum angular velocity that can be driven without hindrance in the current state.
Since the arm 4 can be driven and the ratio of the boom angular velocity to the arm angular velocity for excavating a desired trajectory is maintained, excavation accuracy is also good.

Next, as a result of the comparison in step S ₁₂ , the boom angular velocity is _0.
Is greater than or equal to the maximum boom angular velocity _max , this time, the arm angular velocity ₀ is compared with the maximum arm angular velocity _max (step S ₁₉ ). When the former is less than the latter, that is, when the arm angular velocity ₀ is equal to or greater than the maximum boom angular velocity _max and the arm angular velocity ₀ is less than the maximum arm angular velocity _max , the boom angular velocity ₁ to be output is set to the maximum boom angular velocity _max . (Step S _20). On the other hand, the arm angular velocity ₁ to be output, calculates a value to be maintained the ratio _(0/0) (Step S _21). This value is the same as equation (1) Can be asked as

When it is determined in step S ₁₉ that the arm angular velocity ₀ is greater than or _equal to the maximum arm angular velocity _max , that is, the angular velocities ₀ and ₀ obtained in steps S ₁₀ and S ₁₁ are both the corresponding maximum angular velocities.
_max, when it is more than _max, the ratio of increase in angular velocity obtained for the maximum angular velocity is determined which of the angular velocity is large is made (Step S _22). This judgment is made based on the following equation.

If the expression (3) is satisfied, the ratio of the increase in the arm angular velocity _{0 to} the maximum arm angular velocity _max is equal to the boom angular velocity _0.
It means greater than the maximum boom rate of increase for the angular velocity _max, a series of steps S _17, S ₁₈ to the arm angular speed ₀ and the maximum arm angular velocity _max is executed. On the contrary, if the equation (3) is not satisfied, the ratio of the increase of the boom angular velocity _{0 to} the maximum boom angular velocity _max is calculated as follows.
Since for maximum arm angular speed _max of ₀ will be greater than the rate of increase, a series of steps S _20, S ₂₁ to the boom angular speed ₀ to the maximum boom angular velocity _max is executed.

Thus the boom angular velocity _{1 obtained,} the arm angular speed ₁ is output to the output section 20d, based on the output portion in 20d of these values, control of the required electromagnetic control valve 16, 17 to obtain their angular velocity Output a signal. In controlling the electromagnetic control valves 16 and 17, a control method such as feed back control is adopted, but since such a control method is well known, its explanation is omitted.

As described above, in the present embodiment, when one or both of the boom angular velocity and the arm angular velocity for obtaining the required excavation trajectory is equal to or higher than the predetermined maximum angular velocity, the ratio of the boom angular velocity and the arm angular velocity is maintained. However, since one of the maximum angular velocities is adopted, the excavation can be performed at the maximum angular velocity that does not hinder the operation, and the excavation accuracy is not impaired.

In the above description of the embodiment, the excavation control device for the hydraulic shovel has been described, but it goes without saying that the excavation control device can be applied to excavation control of other machines.

〔The invention's effect〕

As described above, in the present invention, one of the boom angular velocity and the arm angular velocity (each command value) for obtaining the required excavation locus is equal to or greater than each maximum angular velocity obtained from each maximum drive velocity stored in the storage means. When that command value is the maximum angular velocity, when both are greater than or equal to the maximum angular velocity, the command value with the larger difference between the two is set as the corresponding maximum angular velocity, and the other command value is corrected to obtain the required excavation trajectory. The excavation work can be performed at a high speed, and the work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a system diagram of an excavation control device according to an embodiment of the present invention,
FIG. 2 is a flow chart for explaining the operation of the apparatus shown in FIG. 1, and FIG. 3 is a side view of the hydraulic shovel. 3 ... Boom, 4 ... Arm, 6 ... Boom cylinder, 7 ... Arm cylinder, 9 ... Boom angle detector, 10 ... Arm angle detector, 16, 17 ... Electromagnetic control valve, 20 ... Control device.

Claims (1)

[Claims] 1. A hydraulic excavator including a boom driven by a boom cylinder, an arm driven by an arm cylinder, and a hydraulic circuit for driving the boom and the arm, the boom detecting the angle of the boom. Angle detector, an arm angle detector for detecting the angle of the arm, and the maximum drive speed of the boom cylinder and the maximum drive speed of the arm cylinder at a certain arm angle determined from the structure of the hydraulic excavator. Storage means for storing each, and the maximum angular speed of the boom and the maximum angular speed of the arm at the arm angle detected by the arm angle detector based on the maximum drive speeds stored in the storage means Excavation in a predetermined mode is performed corresponding to the detection values of the boom angle detector and the arm angle detector. Second computing means for obtaining the command value of the boom angular velocity and the command value of the arm angular velocity necessary for that, the maximum angular velocities obtained by the first computing means, and the corresponding maximum angular velocities obtained by the second computing means. As a result of comparison by the comparing means for comparing each command value and this comparing means, when only one command value is equal to or more than the corresponding maximum angular velocity, this maximum angular velocity is set as a new command value, and both command values correspond to each other. A command value correcting means for setting a new command value corresponding to the maximum angular velocity having a larger difference between the command value and the maximum angular velocity when the command value is greater than the maximum angular velocity, and the other command when the command value is corrected by the command value correcting means. An excavation control device for a hydraulic excavator, comprising: a third arithmetic means for correcting the value so as to maintain the ratio of the two command values obtained by the second arithmetic means.