JPH04350220A - Automatic control method for excavation work machine - Google Patents

Abstract

PURPOSE:To improve the excavation locus and excavation position control when the excavation reaction force is received. CONSTITUTION:The excavation action of a work machine is set via excavation pattern data 19, and the interpolation, coordinate transformation and overload processing between points of the excavation pattern data 19 are performed by an action locus plan section 20. The positional deviation calculation, positioning check and variable gain in response to the excavating force are performed by a servo-controller 21. A hydraulic valve is controlled by the output signal from the servo-controller 21.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is an open loop link mechanism equipped with a working device such as a bucket or breaker at the tip, and the links are connected by a joint.
The present invention relates to an automatic control method for an excavating work machine, such as a power shovel, which enables the work machine to automatically excavate along a predetermined trajectory.

0002

[Prior Art] Conventional automatic control methods of this type include:
What is known is disclosed in Japanese Unexamined Patent Publication No. 1-318621, which was previously filed by the applicant of the present application. In this prior application, both the position of the cutting edge of the bucket and the digging angle can be made to accurately follow the target trajectory, and the digging position, speed,
By setting the bucket attitude angle in advance, high-precision automatic excavation can be performed without the operator touching the operating lever.

0003

[Problems to be Solved by the Invention] However, in the conventional method, since the excavation reaction force is not taken into account, there is a problem in that excavation accuracy is affected by fluctuations in the excavation reaction force.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an automatic control method for an excavating machine that can improve the excavation trajectory and excavation positioning accuracy when receiving an excavation reaction force. That is.

[0005]

[Means for Solving the Problems] In order to achieve the above object, an automatic control method for an excavating machine according to the present invention uses an open loop link mechanism such as a power shovel, and this link is connected by a joint, and In an excavation work machine equipped with a work machine such as a bucket, the digging operation of the work machine is set as data of each point in order as digging pattern data 19, and joint rotation that detects the rotation angle of each joint using this digging pattern data. Based on the signals from the angle detectors 13, 14, and 15 and the signal from the excavation reaction force detector that detects the operating force of the actuator that rotationally drives each joint, the motion trajectory planning section 20 calculates each of the excavation pattern data. Interpolation calculation that interpolates intermediate trajectories between points, coordinate conversion that converts the coordinates of excavation pattern data to base coordinates, and when overload is determined from the excavation reaction force, the operation trajectory is changed in the direction that reduces the excavation force. The servo control unit 2 performs overload processing that calculates the shift and adds it to the excavation pattern data, and sends operation commands to the servo control unit 2.
1, and this servo control unit 21 calculates the deviation between the given motion command value and the detected value detected by the joint rotation angle detectors 13, 14, 15 to obtain the position deviation, This position deviation is checked, and a gain corresponding to the operation type of the work equipment is determined, and a control signal corresponding to each operation type is output to the hydraulic valve 22, and the hydraulic valve 22 adjusts the pressure and flow according to this control signal. The signal is sent to each actuator. In addition, in the above control method, when an overload is determined from the excavation reaction force and the operating trajectory of the work equipment shifts in the direction of reducing the excavation force, the excavation level at this time is monitored and if the target level is not reached. If it is determined, the depth of digging for that part is repeated.

[0006]

[Operation] Based on the excavation pattern data, the motion trajectory planning section 20 performs trajectory interpolation between the excavation pattern data, coordinate conversion, and overload processing, and the servo control section 21
Then, the deviation between the motion command value from the motion trajectory planning section 20 and the current position is calculated in the servo control section 21, and a gain is set according to the motion, and an output signal based on this is sent to the hydraulic valve 22. Output to the control unit. When an overload is applied to the working machine, the trajectory of the working machine is shifted in the direction in which the excavation force is reduced in the above-mentioned overload processing. Further, the portion where the trajectory of the working machine has been shifted due to overload is excavated repeatedly until the target level is reached.

[0007]

[Embodiment] An embodiment of the present invention will be explained based on the drawings. Note that this embodiment shows a case where a vertical shaft is excavated by an open caisson. In FIG. 2, reference numeral 1 denotes a caisson having a cylindrical shape and driven into the ground, and a ring-shaped running rail 2 is provided on the inner peripheral surface of the caisson 1. As shown in FIG. 3 is an excavating machine with an open loop link mechanism;
is its base, and this base 4 is supported by the traveling rail 2. This excavating work machine 3 has the same configuration as the known one, that is, a boom 5, an arm 6, a bucket 7, and a boom cylinder 8 and an arm cylinder 9 for operating them.
, a bucket cylinder 10, and the base ends of the boom 4 and boom cylinder 8 are supported by the base 4. The base 4 is supported by the running rail 2 via wheels 11, and is driven by a running motor 12. Each of the boom 5, arm 6, and bucket 7 is provided with a boom rotation angle detector 13, an arm rotation angle detector 14, and a bucket rotation angle detector 15, and a boom cylinder 8, an arm cylinder 9, and a bucket cylinder 10. A boom cylinder pressure detector 16, an arm cylinder pressure detector 17, and a bucket cylinder pressure detector 18 are provided in each of the cylinders.

FIGS. 2, 3, and 4 show the working machine coordinate system within the caisson 1 of the excavating working machine 3, which includes (
There are 1) joint rotation angle coordinate system, (2) work machine base coordinate system (orthogonal), and (3) workpiece coordinate system (cylindrical), and the definitions of each are shown below. (1) Joint rotation angle coordinate system This shows the coordinates of the rotation angles of the boom 5, arm 6, and bucket 7 as shown in Figure 2, where θ1 is the boom rotation angle, θ2 is the arm rotation angle, and θ3 is the bucket rotation. Each corner is shown. Then, the rotational fulcrum of the boom 5 is 01, the rotational fulcrum of the arm 6 is 02, and the rotational fulcrum of the bucket 7 is 0.
3, boom 5 is 01 -02 and arm 6 is
are indicated by 02 -03 , and bucket 7 is indicated by a line connecting 03 to the tip of bucket 7 . Also, the above boom rotation angle θ1 is such that the lower side is - with respect to the horizontal line passing through 01.
θ1, the upper side is indicated by +θ2, and the arm rotation angle θ
2 is below -θ2 with respect to the extension line of 01 -02
, the upper side is indicated by +θ2, and the bucket rotation angle θ3
is +θ3 on the lower side with respect to the extension line of 02 -03
, the upper side is indicated by -θ3. (2) Work equipment base coordinate system (orthogonal) As shown in Fig. 3, this is defined as an orthogonal coordinate system with the origin at the rotation fulcrum 01 of the boom 5, and the x direction is the origin 01.
The y direction is defined as the horizontal direction, vertically downward. α is defined as the angle at which the line connecting 03 of the bucket 7 and the cutting edge intersects with the horizontal plane, and indicates the attitude of the bucket 7, which is called the bucket ground diagonal. (3) Workpiece coordinate system (cylindrical) As shown in FIG. 4, this is defined as a cylindrical coordinate system in which the coordinate origin is the intersection point 04 of the center of the caisson 1 and the horizontal line passing through the tip of the caisson cutting edge. As shown in Figures 3 and 4, the X direction is defined by the rotation angle of the work machine that rotates from the origin 04 toward the cutting edge, the Z direction from the origin 04 upward, and the β direction from the origin 04. be done. α is the bucket ground diagonal as in the case (2) above.

FIG. 1 shows an outline of automatic control according to an embodiment of the present invention, and in this figure, excavation pattern data 19 refers to the excavation pattern data 19, as shown in FIG. This is data for each point whose motion is defined in order as shown by A, B, C, . . . G, and is defined in the workpiece coordinate system. Further, in the motion trajectory planning 20, the following calculations are performed in accordance with pattern instructions from the excavation pattern data. (1) Interpolation calculation A calculation is performed to interpolate the intermediate trajectory between each point of the excavation pattern data. In this example, the types of interpolation are:
These include linear interpolation, joint rotation angle interpolation, circular interpolation, etc., and these are calculated in the base coordinate system. (2) Coordinate transformation First, the excavation pattern data defined in the workpiece coordinate system is transformed into the base coordinate system. The other is to convert from the base coordinate system to the joint rotation angle coordinate system, and vice versa, from the joint rotation angle coordinate system to the base coordinate system. (3) Overload processing Pressure detectors 16, 17, 18 for each cylinder 8, 9, 10
If an overload is determined from the excavation reaction force detected in , this means that the excavation reaction force is greater than a certain judgment value and the pressure oil to each cylinder has stalled and the excavation work machine 3 has stopped. The judgment that the operation of this excavating work equipment 3 has stopped is made by calculating the operating speed from the respective joint rotation angles of the boom 5, arm 6, and bucket 7 detected by the rotation angle detectors 13, 14, and 15. If this operating speed is smaller than a certain judgment value, it is determined that the operation of the excavating machine has stopped. When an overload condition is detected in this way, the overload process is performed by leaving the normal automatic control execution state based on the above-mentioned motion locus inclination angle. That is, processing is performed to shift the motion locus of the bucket 7 in a direction that reduces the load applied thereto. That is, data such as shifting the movement locus of the bucket 7 upward or escaping in the opposite direction to the excavation direction is added to the input signal from the excavation pattern data. Based on the above calculations and the speed data in the excavation pattern data, the amount of operation per unit time is calculated and outputted to the servo control section 21 as an operation command value. The servo control section 21 performs the following calculations. (1) Deviation Calculation Positional deviation is calculated from the motion command value given from the motion trajectory planning section and the current value calculated from the joint rotation angle detected by each rotation angle detector 16, 17, 18. Position deviation=operation command value−current value (2) Compare the target position data of the positioning check excavation pattern data with the current value, and if this value is within the positioning completion range, proceed to the next point. At this time, an overload may be applied and the target positioning completion range may not be reached. Therefore, 1) the operating time is monitored, and if this operating time exceeds the allowable range, it is determined that the positioning is complete. 2) It is determined that positioning is complete when the work machine passes the target point in the X direction (work coordinate system). This makes it possible to avoid hunting during excavation positioning. 3) Variable gain The gain is changed according to the excavation reaction force, and this value is multiplied by the deviation and used as the command value to the hydraulic valve. Specifically, when the motion type of the excavation pattern data is a digging motion (points B, C, and D in FIG. 5) and when the motion type is an aerial motion (points A and D in FIG. 5),
E, F, G), change the gain. That is, in the case of excavation operation, the gain is increased so that excavation force can be obtained. Furthermore, in the case of excavation operation, the operating speed calculated in the overload processing section is used, and the actual operating speed is compared with the commanded operating speed, and the actual operating speed is slower than the commanded operating speed. If this occurs, increase the gain continuously. This gain is continuously increased until the output to the hydraulic valve is maximized. The hydraulic valve 22 applies pressure and flow rate to each hydraulic cylinder 8, 9,
10, thereby rotating each joint.

An example of calculation of coordinate transformation in the motion trajectory planning section 20 shown in FIG. 1 will be described below for reference. (1) Base coordinate system from joint rotation angle

[0011]

[Math 1]

(2) Joint rotation angle from base coordinate system

00
13]

[Math 2]

(3) Base coordinates from work coordinate system

[Number 3
]

(4) From the base coordinate system to the work coordinate system

0
016]

[Math 4]

Next, the concrete effect of the overload processing in the above embodiment will be explained with reference to FIGS. 6 and 7. Assume that the bucket 7 is excavating, that is, when moving from point A to point D, an overload stall state occurs. If this state is, for example, point C', the data for trajectory interpolation during this period is defined in the workpiece coordinate system as follows:
Starting point of interpolation (point C)...(X, Z, α) = (Xc,
Zc, αc) End point of interpolation (point D)...(X, Z
, α) = (XD, ZD, αD) Current point (point C')...(X, Z, α) = (Xc', Zc', α
c'). The current point is each rotation angle detector 16, 17,
The joint rotation angle is calculated from the joint rotation angle detected in step 18. Here, in order to avoid an overload stall state, a new trajectory is planned, for example, an upward escape trajectory. Starting point of new interpolation (point C')...(Xc', Zc'
, αc′) End point of new interpolation (upward dZ point)…(Xc′,
Zc'+dz, αc') For example, linear interpolation is performed between the starting point and the ending point. This allows you to avoid an overload stall condition by escaping upwards. And when bucket 7 reaches the new end point, the next starting point (upward dz point)...(Xc', Zc'+
dz, αc') Next end point (point D)...(XD, ZD, αD)
Performs interpolation and performs automatic control. Furthermore, if the vehicle escapes upward by dZ and reaches a stall state due to overload while moving to point D, the same method is repeated a predetermined number of times or a predetermined height (dZ). If point D cannot be reached even after repeating this predetermined number of times or the predetermined height, the end point is also moved upward. In other words, if the point at this time is D', the starting point...(XD
′, ZD ′+dz, αD ′) End point…(XD , Z
D + dZD, αD) By this method, an overload stall state can be avoided and automatic control operation can be executed continuously without interruption.

In the above embodiment, when the excavating machine is overloaded, the trajectory of the bucket 7 escapes upward, so if the soil is hard, it may not be possible to excavate to the target excavation level. Furthermore, if the excavation has not been completed to the target excavation level, that is, if soil remains, it will be difficult to advance the excavation forward. Therefore, as a method for solving the above problem, the following embodiment will be described with reference to FIGS. 5 and 7. In Fig. 5, normally bucket 7 operates in order from point A, excavates from point C to D, removes soil from G, then moves to point H as shown in the figure, and moves from point I to J. Excavation will be carried out at point M, and soil will be removed at point M. In this embodiment, when the excavation from points C to D does not reach the target excavation level L1, point G
After discharging soil at , instead of proceeding to point H,
Return to the previous point, point B, and excavate again. The action will be explained in detail below. (1) Coordinate data (X, Z, α) used by general robots as excavation trajectory pattern data, interpolation type,
In addition to speed, it has data called movement type. The operation types include digging start, excavation, earth removal, and no-load movement. Here, "start excavation" is the point at which excavation begins, and point C in FIG. 5 is this operation type. "Drilling" is a point where digging is being performed, and point D in FIG. 5 is this operation type. "Earth removal"
is the point where the soil removal operation is performed, and is the point G in Figure 5.
has this behavior type. "No-load movement" refers to points other than the above, points of movement in the air, and points A, B, E, and F in FIG. 5 are of this movement type. (2) As a method of monitoring the excavation level, the joints obtained from the joint rotation angle detectors 13, 14, 15 while the excavation operation is being executed, that is, from the operation type "start excavation" to "excavation" Calculate the value of the workpiece coordinate system from the rotation angle. Specifically, the Z coordinate of the workpiece coordinate system is calculated and stored in steps of distance dx from point C to point D. Then, when point D is reached, this average value is taken and this is set as Zm. At this time, if the target value for excavation is Zr, it is determined to repeatedly excavate when Zm>Zr. Automatic operation is executed to the next point, and when the operation type reaches the "earth removal" point, that is, in this example, points E, F,
If point G is reached by executing "G" and if a decision to excavate has been made repeatedly at this time, the movement to the point before "start excavation" of point B instead of point H is executed. This trajectory planning is repeated until the amount or level of excavation reaches the target value. This ensures that the target excavation amount or excavation level is obtained even when the soil is hard.

[0019]

According to the present invention, when performing automatic excavation according to excavation pattern data, it is possible to improve the excavation locus and excavation positioning accuracy when receiving an excavation reaction force. In addition, if an overload is applied to the work equipment and the excavation trajectory of the machine is shifted, this part can be excavated repeatedly until the target level is reached.In the case of hard soil, the excavation path can be easily reached to the target excavation level. can do.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram showing an embodiment of the present invention.

FIG. 2 is a side view showing excavation work using a caisson.

FIG. 3 is a side view for explaining the coordinate system of the excavating machine.

FIG. 4 is a top view for explaining the coordinate system of the excavating machine.

FIG. 5 is an explanatory diagram showing the excavation pattern of the excavating machine.

FIG. 6 is an explanatory diagram showing the excavation pattern of the excavating machine.

FIG. 7 is an explanatory diagram showing the excavation pattern of the excavating machine.

[Explanation of symbols]

1 Caisson, 2 Traveling rail, 3 Excavation work machine, 4 Base, 5 Boom, 6 Arm, 7 Bucket, 8 Boom cylinder, 9 Arm cylinder, 1
0 Bucket cylinder, 13, 14, 15 Rotation angle detector, 16, 17, 18 Cylinder pressure detector, 1
9 excavation pattern data, 20 motion trajectory planning section,
21 Servo control unit, 22 Hydraulic valve.

Claims (2)

[Claims] Claim 1: In an excavating machine such as a power shovel, which has an open-loop link mechanism, the links are connected by joints, and is equipped with a bucket or other working implement at the tip, the excavating operation of the working machine is sequentially recorded at each point. is set in the excavation pattern data 19, and the joint rotation angle detectors 13 and 1 detect the rotation angle of each joint using this excavation pattern data.
Based on the signals from 4 and 15 and the signal from the excavation reaction force detector that detects the operating force of the actuator that rotationally drives each joint, the motion trajectory planning section 20 calculates the intermediate points between each point of the excavation pattern data. Interpolation calculation to interpolate the trajectory, coordinate transformation to convert the coordinates of excavation pattern data to base coordinates, and calculation to shift the operation trajectory in the direction to reduce the digging force when an overload is determined from the digging reaction force. performs overload processing to be added to the excavation pattern data and outputs an operation command to the servo control unit 21, and this servo control unit 2
1, the given motion command value and the joint rotation angle detector 1
Calculate the deviation from the detection values detected in steps 3, 14, and 15 to obtain the position deviation, check this position deviation, and further calculate the gain according to the operation type of the work equipment and calculate the position deviation according to each operation type. 1. An automatic control method for an excavating machine, characterized in that a control signal is output to a hydraulic valve 22, and the hydraulic valve 22 sends pressure and flow to each actuator according to the control signal. [Claim 2] In the above claim (1), when an overload is determined from the excavation reaction force and the operating trajectory of the work equipment shifts in a direction in which the excavation force is reduced, the excavation level at this time is monitored. 2. The automatic control method for an excavating machine according to claim 1, wherein if it is determined that the target level has not been reached, the digging depth of that portion is repeated.