JPH09224409A - Device for controlling deep cultivation of working machine for earth-moving vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling deep cultivation of a working machine for earth-moving vehicle which receives no influence of the disturbance of a deep cultivation feedback signal and is capable of controlling deep cultivation which is satisfactory in deep cultivating accuracy at a long slope. SOLUTION: This device is provided with a first low-pass filter 67 outputting the low frequency component signal of a deep cultivation detecting value, a tilting angle high frequency component detecting means outputting the high frequency component signal of a back and forth tilting angle signal and a controller correcting a deviation signal E between a desired deep cultivation value and the output value of the low-pass filter 67 by means of the output value of the tilting angle high frequency component detecting means and controlling the ascending and descending of the working machine to reduce the deviation signal E. The tilting angle high frequency component detecting means is provided with an angular rate detector 64 detecting the rate of the tilting angle and a second low-pass filter outputting the low frequency component signal of the rate of the tilting angle (1) and is provided with the angular rate detector 64, an integrator 65 integrating an angular rate signal and a high-pass filter 66 outputting the high frequency component signal of this integration output (2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working machine tilling depth control device for an earthmoving vehicle which controls the working machine up and down to keep the tilling depth constant.

[0002]

2. Description of the Related Art There is an earthmoving vehicle having a crawler or a wheel as a traveling device on a vehicle body so that the vehicle can travel and turn and a working machine such as a cultivator is provided at a rear portion of the vehicle body. Then, in the tilling work by the earthmoving vehicle, there is a work for making the depth of tilling the field (hereinafter referred to as tilling depth) constant. Since it is difficult to manually operate the operation lever for raising and lowering the working machine to make the working depth constant, a working depth control device that automatically controls the working depth has been proposed. Various methods for obtaining a feedback signal of the working depth have been well known in the automatic working depth control.

For example, Japanese Laid-Open Patent Publication No. 7-115804 proposes a method of detecting the working depth by the rotation angle of a rear cover provided at the rear end of the working machine. FIG.
An example of the wheel type earthworking vehicle described in the publication is shown, which will be described below with reference to FIG. The earthmoving vehicle 1 is provided with wheels 2 and 3 at the front and rear of the vehicle body, respectively, so that the vehicle can travel freely, and a steering handlebar 9 provided at the front of the driver's seat allows the vehicle to turn left and right. At the rear end of the earthmoving vehicle 1, there is provided a working machine 7 such as a rotary connected by a so-called three-point link hitch. That is, one upper link 5 is provided at the upper rear center of the vehicle body.
A pair of lower links 6 are rotatably attached to the left and right of the lower rear part. A lift arm 11 is rotatably attached to the left and right of the rear part of the vehicle body.
Lift rods 8 are rotatably mounted on the left and right sides between the rear end of the first unit 1 and the substantially center of the lower link 6. The rod side of the lift arm cylinder 4 is rotatably attached to the lift arm 11, and the tube side of the lift arm cylinder 4 is rotatably attached to the rear part of the vehicle body. A working machine 7 such as a cultivator is attached to the tip ends of the upper link 5 and the lower link 6, and when the lift arm cylinder 4 is expanded and contracted, work is performed via the lift arm 11, the lift rod 8 and the lower link 6. The machine 7 can be raised and lowered.

A rear cover 13 which is rotatable in the front-rear direction is provided at the rear end of the working machine 7, and a working depth detector 63 for detecting the working depth is provided at the upper part of the working machine 7. The rear cover 13 is adapted to rotate depending on the working depth of the working machine 7, and the working depth detector 63 detects the working depth by detecting the turning angle of the rear cover 13.
The output signal of the working depth detector 63 is input to a controller (not shown). Further, a not-illustrated tilling depth setting device (potentiometer or the like) is provided for setting the tilling depth at the tilling depth control, and the tilling depth setting signal from this tilling depth setting device is input to the controller. Further, a switching valve (not shown) that controls expansion and contraction of the lift arm cylinder 4 is provided, and the controller outputs a switching signal to this switching valve to supply the pressure oil discharged from the hydraulic pump to the lift arm cylinder 4. The expansion and contraction of the lift arm cylinder 4 is controlled.

By the way, a control block diagram in such a configuration is shown, for example, in FIG. 8, and the operation will be described below with reference to FIG. When automatically controlling the working depth, the controller obtains a deviation between the working depth setting signal from the working depth setting device 62 and the output signal of the working depth detector 63, amplifies this deviation, and causes the solenoid valve drive unit 28 to perform the amplification. The changeover valve is changed over and the lift arm cylinder 4 is driven by this to control the lifting and lowering of the working machine 7. As a result, the working depth of the working machine 7 is controlled to the depth set by the working depth setting device 62. It should be noted that although the same publication shows that the dead zone is provided in the deviation amplification section, it is omitted in the above description.

In addition to the above-mentioned method, a method using a laser receiver 52 provided on the upper part of the working machine 7 as a working depth detecting means has been proposed. FIG. 9 is an explanatory view of an earthworking vehicle by this method. Is. Laser projector 51 is placed at the reference position in the field.
Is provided, and the reference laser beam 53 is projected from the laser projector 51 while rotating in the horizontal plane. The laser receiver 52 has light receiving sensors arranged in the vertical direction.
The relative height between the reference laser beam 53 and the working machine 7 is detected from the position of the light receiving sensor that receives the reference laser beam 53. The controller calculates the height of the working machine 7 from this relative height and detects the working depth. The control block diagram in this case is also shown in the same way as in FIG. 8, and the operation is also the same.

Further, since the height of the working machine changes according to the magnitude of the tilt angle of the vehicle body, a method of correcting the working machine height based on this tilt angle has been proposed. JP 63
No. 7704 discloses this example, and FIG. 10 shows an earthmoving vehicle according to the publication. For example, when the front part of the vehicle body is raised, the work implement at the rear part is lowered by a height corresponding to the tilt angle, and when the front part of the vehicle body is lowered, the work implement is moved by the above height. Since it only rises, it is necessary to correct this height. Therefore, according to the publication, an inclination angle sensor 15 for detecting the vehicle body inclination angle is provided in the vicinity of the rear wheel axle of the earthmoving vehicle, and an angle sensor 16 is provided on the base end rotation shaft of the lift arm 11. A controller (not shown) lowers the lift arm 11 so that the working depth becomes a working depth set value when the vehicle body is in a horizontal state. When the vehicle body is tilted by the angle θ, the lift arm cylinder 4 is driven to move the lift arm 11 up and down by the angle θ, and the height of the working machine 7 is corrected. In this way, it becomes possible to perform tillage depth control such that the tillage depth becomes the set tillage depth value even on a rough land with unevenness.

[0008]

However, in the working depth control device which obtains the feedback signal of the working depth by the rotation angle of the rear cover 13 as described above, the working machine 7 is used.
When the rear cover 13 is hit by a clod or stump that cannot be broken (rotary, etc.), or a large stone on the surface of the field or in the ground, the feedback signal from the working depth detector 63 is disturbed, and the finished working depth is set to the set value. It doesn't pass. FIG. 11 shows the state of the plowing depth control at this time.
When a large stone or a stump hits the rear cover 13, the rear cover 13 jumps up and rotates a lot, so that the feedback signal of the working depth suddenly increases. For this reason, the deviation increases, and the controller determines that the working depth has become deeper than the set value, and raises the work implement 7. As a result, the finished working depth becomes shallower than the set working depth at the position of the stone or stump, and there is a problem that the working depth is not constant.

Further, in the tilling depth control device for receiving the reference laser light 53 by the laser receiver 52 provided on the upper part of the working machine 7 to obtain the tilling depth feedback signal, the laser projector is caused by the vibration when the automobile or the like runs. 51 oscillates, or the reference laser beam 53 sways due to wind. Therefore, the height position of the reference laser beam 53 is disturbed,
As a result, disturbance occurs in the working depth feedback signal, so that the working depth is not constant.

Further, when controlling the height of the work implement 7 in accordance with the inclination angle of the vehicle body, if the vehicle body continues to run on a long sloping ground having a constant inclination angle, the inclination of the vehicle body The work machine 7 travels while being raised or lowered according to the corner. That is, as shown in FIG. 12, since the working machine 7 travels while being raised on an uphill where the inclined state continues for a long time, the plowing depth h is controlled to be shallower than the set plowing depth value H. On the contrary, on a long downhill, the working machine 7 remains lowered, so that the plowing depth is controlled deeper than the set plowing depth value. For this reason, there is a problem in that the precision of tillage depth on sloping ground is not good.

The present invention has been made by paying attention to such a problem, and it is possible to perform the plowing depth control which is not affected by the disturbance of the plowing depth feedback signal and has a favorable plowing depth accuracy even on a long sloping land. It is an object of the present invention to provide a working machine tillage depth control device for an earthmoving vehicle.

[0012]

Means for Solving the Problems, Actions and Effects In order to achieve the above-mentioned object, the invention according to claim 1 is a working machine 7 provided at the rear end of an earthworking vehicle 1 so as to be able to move up and down, A plowing depth detector 63 for detecting the plowing depth (plowing depth) of the working machine 7,
A tilling depth setting device 62 for setting a target tilling depth value, and a controller for controlling the raising and lowering of the working machine 7 so that the deviation between the tilling depth value of the tilling depth setting device 62 and the detection value of the tilling depth detector 63 becomes small. 5
In the working machine tilling depth control device of the earthmoving vehicle having
A first low-pass filter 67 that outputs a low-frequency component signal of the detection value of the tilling depth detector 63, a tilt angle high-frequency component detecting unit that detects a high-frequency component signal of a tilt angle in the front-rear direction of the earthworking vehicle 1, and a tilling depth. The deviation signal E between the plowing depth value of the setting device 62 and the output value of the first low pass filter 67 is corrected by the output value of the inclination angle high frequency component detecting means, and the working machine 7 is moved up and down so that the deviation signal E becomes small. And a controller 55 for controlling the.

According to the first aspect of the invention, the disturbance superimposed on the output signal of the working depth detector is removed by the first low-pass filter, so that the deviation signal is not affected by the disturbance. Therefore, the disturbance of the finished working depth due to the disturbance is eliminated, and the working depth can be controlled according to the set working depth value.
On the other hand, since the responsiveness is lowered by passing the tilling depth feedback signal through the low-pass filter, the tilling depth accuracy on the uneven land is lowered. In order to improve this, the command signal of the lift arm cylinder 4 is corrected by feeding back the high frequency component of the tilt angle. That is,
The high frequency component signal of the inclination angle detected by the inclination angle high frequency component detecting means is fed back to correct the deviation signal. Therefore, when the earthmoving vehicle 1 cultivates uneven land or digs in a place where a flat land changes to a sloping ground, the speed of the lift arm cylinder 4 follows the rapid change in the inclination angle. Since the deviation signal is corrected, the followability of the plowing depth control is improved. Further, when the inclination angle becomes constant after entering the sloping ground, the above correction of the deviation signal is undone, so that the height of the working machine is not wastefully corrected in accordance with the inclination angle. The plowing depth control accuracy can be improved.

The invention described in claim 2 is the same as claim 1
In the working machine tillage depth control device for an earthworking vehicle according to item 4, the inclination angle high frequency component detecting means includes an angular velocity detector 64 for detecting an inclination angular velocity in the longitudinal direction of the earthworking vehicle 1, and a low frequency output signal of the angular velocity detector 64. The second low-pass filter 68 equivalently outputs a high-frequency component signal having a tilt angle by outputting the component signal.

The invention according to claim 3 is the same as claim 1
In the working machine tillage depth control device for an earthworking vehicle according to item 7, the inclination angle high frequency component detecting means integrates an angular velocity detector 64 for detecting an inclination angular velocity of the earthmoving vehicle 1 in the front-rear direction, and an angular velocity signal from the angular velocity detector 64. And a high-pass filter 66 that outputs a high-frequency component signal of the output signal of the integrator 65.

According to the second and third aspects of the present invention, the inclination angle high frequency component detecting means corrects the height of the working machine in response to a sudden change in the vehicle body inclination angle. As a means to detect such a sudden change in tilt angle,
There are the following means. That is, in claim 3, the inclination angle high frequency component detecting means obtains the inclination angle by integrating the longitudinal angular velocity of the earthmoving vehicle 1 and detects the high frequency component signal of this inclination angle. Further, in claim 2, the inclination angle high frequency component detection means equivalently detects the high frequency component signal of the inclination angle by detecting the low frequency component signal of the inclination angular velocity in the front-rear direction of the earthworking vehicle 1. The signal according to claim 2 is substantially equivalent to the signal according to claim 3,
Compared with the signal according to claim 3, there is no accumulated error obtained by integrating drift and offset of the angular velocity detector, so that a high-frequency component signal with a more accurate tilt angle can be detected. Further, since the number of control components is small, there is no signal delay and it is practical. Since the deviation signal is corrected by the high frequency component signal of the inclination angle obtained by any one of the inclination angle high frequency component detecting means, the followability of the plowing depth control with respect to the rapid change of the inclination angle is improved. Further, when the inclination angle becomes constant after entering the sloping ground, the above correction of the deviation signal is undone, so that the height of the working machine is not wastefully corrected in accordance with the inclination angle. The plowing depth control accuracy can be improved.

Further, the invention according to claim 4 is the working machine tillage depth control device for an earthmoving vehicle according to claim 1, 2 or 3, wherein the tilling depth detector 63 is provided with a rear cover 13 of the working machine 7. It is configured to detect the moving angle. The invention according to claim 5 is the working machine tillage depth control device for an earthmoving vehicle according to claim 1, 2 or 3, wherein the tiller depth detector 6 is used.
3 is configured to detect the relative position between the reference laser beam 53 and the working machine 7 by the laser light receiver 52 attached to the working machine 7.

According to the fourth aspect of the present invention, when the working depth is detected by the rotation angle of the rear cover of the working machine, the rear cover bounces due to a stump or a large stone, and the working depth detector is detected. Even if a sudden change (disturbance) in the feedback signal of 1 occurs, the first low-pass filter removes this disturbance signal. Therefore, the finished plowing depth is controlled so as to reach the plowing depth set value without being affected by the disturbance. Therefore, the present invention is effective in the case of the working depth detector based on the rotation angle of the rear cover. Further, according to the invention described in claim 5, the relative position between the reference laser beam and the working machine is detected by the laser light receiver attached to the working machine, and the working depth is detected based on this relative position. In this case, even if the disturbance of the reference laser beam due to the vibration of the laser projector or the wind due to the vibration of the ground occurs and the disturbance of the feedback signal of the working depth detector occurs, the disturbance is caused by the first low-pass filter in the same manner as above. Remove the signal. Therefore, the finished plowing depth is controlled so as to reach the plowing depth set value without being affected by the disturbance. Therefore, the present invention is effective in the case of a working depth detector using a laser receiver.

Further, the invention according to claim 6 is a working machine 7 provided at the rear end of the earthworking vehicle 1 so as to be able to move up and down, and a plowing depth detection for detecting a plowing depth (plowing depth) of the working machine 7. Device 63, tilling depth setting device 62 for setting a target tilling depth value, and tilling depth setting device 6
The working machine working depth control device for an earthworking vehicle, which is provided with a controller 55 that outputs a lifting command for the working machine 7 based on the deviation so that the deviation between the working depth value 2 and the detection value of the working depth detector 63 becomes small. In the above, the controller 55 regards the limit value as a deviation when the deviation becomes larger than a predetermined limit value, and outputs a lifting command for the working machine 7 based on the limit value.

According to the invention of claim 6, when a large disturbance suddenly occurs in the feedback signal of the tilling depth detector, the tilling depth value of the tilling depth setting device and the feedback value of the tilling depth detector are compared. Although the deviation suddenly becomes large, this deviation signal is suppressed so as not to become larger than a predetermined limit value. Therefore, the influence of sudden disturbance of the feedback signal of the working depth detector is suppressed, and the accuracy of the finished working depth is improved.

The invention according to claim 7 is the same as that of claim 6.
In the working machine tillage depth control device for an earthmoving vehicle described in [3], the limit value can be set arbitrarily.

According to the seventh aspect of the invention, the limit value of the deviation signal can be arbitrarily set, and the followability of the lift arm cylinder 4 can be changed according to the unevenness of the field. Therefore, it is possible to accurately control the working depth according to the uneven state.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. 1 to 3 show the first embodiment. A side view of the earthmoving vehicle 1 according to the present embodiment is shown in FIG. 1, and a block diagram of the structure is shown in FIG. In this example, an example of the earthworking vehicle 1 including the tilling depth detector 63 that detects the rotation angle of the rear cover 13 as the tilling depth detecting means is shown. The construction of the earthworking vehicle 1 is the same as that of FIG. 7 described in the related art, and the same reference numerals are given to the same constructions, which will be briefly described below. At the rear end of the vehicle body, a three-point link hitch, that is, one upper link 5 at the center upper part, and a working machine 7 such as a rotary connected by a pair of lower left and right lower links 6 are provided. Lift arms 11 are rotatably attached to the left and right of the rear part of the vehicle body,
The rear end of the lift arm 11 is connected to the lower link 6 via the lift rod 8. Also, the lift arm 1
The lift arm cylinder 4 can move up and down, and the work arm 7 can be moved up and down via the lift rod 8 and the lower link 6 by expanding and contracting the lift arm cylinder 4. Further, a working depth detector 63 as a working depth detecting means for detecting the rotation angle of the rear cover 13 is provided on the upper part of the working machine 7. The vehicle body is also provided with an angular velocity detector 64 for detecting the tilt angle in the front-rear direction.

The tilling depth setting device 62 is for setting the tilling depth and is provided, for example, on the panel 10 or the like at the front of the driver's seat. The tilling depth setter 62 and the tilling depth detector 63 are constituted by, for example, potentiometers, and the angular velocity detector 64 is constituted by a gyro or the like. The controller 55 is composed of a general computer system mainly including a microcomputer, and includes a control unit 27 and an A / D conversion unit 2.
6 and a solenoid valve drive unit 28. Plowing depth setting device 6
2. The output signals of the tilling depth detector 63 and the angular velocity detector 64 are input to the controller 27 via the A / D converter 26,
An elevation command signal for the lift arm 11 is output to the solenoid valve drive unit 28 by the arithmetic processing. Solenoid valve drive unit 28
Outputs a current signal proportional to the magnitude of the up / down command signal. In the case of a rising command, this current signal is guided to the solenoid operating portion 33d of the switching valve 33, and in the case of a falling command, this current signal is guided to the solenoid operating portion 33e of the switching valve 33.

The switching valve 33 drives the lift arm cylinder 4. Since this embodiment shows an example in which a single-acting cylinder is used as the lift arm cylinder 4, the switching valve 33 is a three-port switching valve. The input port of the switching valve 33 is connected to the hydraulic pump 3 via the pipe line 42.
2 and the return oil port is connected to the tank 31 via the conduit 43. The output port of the switching valve 33 is connected to the bottom hydraulic chamber 4 a of the lift arm cylinder 4 via a pipe 45.

When a rising command is output from the control unit 27 to the solenoid valve drive unit 28, a current signal is guided to the solenoid operating unit 33d of the switching valve 33, and the switching valve 33 is switched to the a side. As a result, the pressure oil discharged from the hydraulic pump 32 flows into the bottom hydraulic chamber 4a of the lift arm cylinder 4 via the pipe 42 and the pipe 45 at a flow rate according to the magnitude of the above-mentioned rise command. Then, the lift arm cylinder 4 raises the lift arm 11 at a speed proportional to the flow rate. When the control unit 27 outputs a descending command to the solenoid valve drive unit 28, a current signal is guided to the solenoid operating unit 33e of the switching valve 33, and the switching valve 33 is switched to the c side.
At this time, the rod of the lift arm cylinder 4 is pushed downward by the weight of the working machine 7, the lift arm 11, etc., and the oil flows out from the bottom side hydraulic chamber 4a, and the tank 31 passes through the pipe line 45 and the pipe line 43. Drain to. Therefore,
The lift arm 11 descends due to its own weight. In addition,
The pressure oil discharged from the hydraulic pump 32 drains to the tank 31 via the pipe line 42 and the pipe line 43.

The configuration of the control unit 27 will be described in detail with reference to the control block diagram of FIG. The A / D converter 26 is omitted in FIG. The tilling depth value signal from the tilling depth setter 62 represents the control target value. Plow depth detector 63
The detection value signal from is input to the first low-pass filter 67, and the low-frequency component signal of the detection value signal is output from the low-pass filter 67. The deviation between the plowing depth value signal and the low-frequency component signal of the detection value signal is calculated, and this is the plowing depth deviation signal E. Further, the angular velocity signal from the angular velocity detector 64 is input to the integrator 65 and converted into the tilt angle signal θ, and the tilt angle signal θ is input to the high pass filter 66. Further, the high-pass filter 66 uses the tilt angle signal θ.
Is output, and the high frequency component signal is amplified by a predetermined factor. Then, the difference between the deviation signal E and the high frequency component signal of the amplified tilt angle signal θ is calculated,
This difference signal is amplified by the amplifier and the solenoid valve drive unit 2
8 is output as an ascending or descending command. The solenoid valve drive unit 28 outputs a current signal to the switching valve 33 as described above based on this ascending or descending command, thereby driving the lift arm cylinder 4 to control the lifting and lowering of the working machine 7.

Next, the operation of the tilling depth control device having the above structure will be described. Disturbances superposed on the detection value signal of the working depth detector 63 are removed by the first low-pass filter 67. As a result, the deviation signal E between the working depth value signal from the working depth setting device 62 and the output signal of the first low-pass filter 67 is not affected by the disturbance of the working depth feedback signal. The lift command is output stably. Therefore, even if the rear cover 13 suddenly jumps up due to a stump or the like, the disturbance of the finished working depth due to this is eliminated, and the accurate working depth control becomes possible.

On the other hand, since the inclination angle of the vehicle body changes abruptly in an uneven land or a place where a flat land changes to a sloping ground, the height of the working machine 7 is corrected with good responsiveness according to the magnitude of the change in the inclination angle. There is a need. However, in a long sloping land (such as an upslope or downslope field) where the inclination angle does not change so much, the height correction of the working machine 7 must be restored.
Therefore, as shown in FIG. 3, a high frequency component signal of the tilt angle signal θ (a signal obtained by integrating the angular velocity signal of the angular velocity detector 64) is obtained by the high pass filter 66, and the deviation signal E is corrected by this high frequency component signal. There is.

Here, the sign of the plowing depth is based on the height of the ground surface (= 0), and the downward direction (the direction in which the plowing depth becomes deep) is positive. The sign of the deviation signal E (which corresponds to a speed command for raising or lowering the lift arm 11) is such that the downward direction of the lift arm 11 is positive and the upward direction is negative. Further, when the front part of the vehicle body faces upward, the sign of the vehicle body inclination angle is positive. At this time, for example, when the plowing depth feedback signal is larger than the plowing depth value signal, that is, when the finished plowing depth value is deeper than the plowing depth setting value, the sign of the deviation signal E becomes negative, and the solenoid valve drive unit 28. A negative command signal is output to. Therefore, the lift arm 11 rises and the deviation signal E decreases. Next, for example, when the front part of the vehicle body suddenly rises and the inclination angle increases in the positive direction, it is necessary to raise the lift arm cylinder 4 at a speed according to the magnitude of the change in the inclination angle. In such a case, the high frequency component signal of the inclination angle signal θ output from the high pass filter 66 becomes a positive signal proportional to the magnitude of the change in the inclination angle, and therefore this positive high frequency component signal is subtracted from the deviation signal E. Then, the correction signal is obtained. Therefore, this correction signal is corrected so as to improve the followability of the lift arm 11 in the ascending direction, and is amplified and output. Similarly, when the front portion of the vehicle body suddenly descends and the inclination angle decreases in the negative direction, a correction signal is obtained by subtracting the negative high frequency component signal of the inclination angle from the deviation signal E, and the lift signal is lifted. The followability of the arm 11 in the descending direction is improved. As a result, the responsiveness of the height correction of the work implement 7 is improved with respect to a rapid change in the inclination angle, and the plowing depth accuracy is improved. On a slope having a long slope where the slope angle does not change, the high frequency component signal of the slope angle signal θ becomes 0, and the deviation signal E cannot be corrected. Therefore, the finished tillage depth becomes constant according to the tillage depth setting value, and the tillage depth accuracy on the sloping land is improved.

In the present embodiment, the turning angle of the rear cover 13 is detected, and this turning angle is used as the plow value feedback signal, but the present invention is not limited to this, and as shown in FIG. 9, for example. The reference laser beam is received by the laser receiver, and the position of the received reference laser beam and the working machine 7
It is also possible to detect the working depth by the relative position of. Although the lift arm cylinder 4 is a single-acting cylinder, it may be a double-acting cylinder. In this case, a 4-port type switching valve can be used so as to simultaneously control the bottom side hydraulic chamber and the head side hydraulic chamber of the lift arm cylinder 4. And
The control characteristic when the lift arm cylinder 4 is lowered is improved.

Next, a second embodiment will be described with reference to FIG. In this embodiment, a signal equivalent to the high frequency component signal of the tilt angle signal θ in the first embodiment is obtained by another method. FIG. 4 is a control block diagram showing this method, in which the same components as those in FIG. 3 are designated by the same reference numerals. Here, a signal equivalent to the high frequency component signal of the tilt angle signal θ is obtained by inputting the angular velocity signal from the angular velocity detector 64 to the second low pass filter 68 which is a pseudo low pass filter. Here, the meaning of the pseudo low-pass filter is that the output signal of the second low-pass filter 68, which is a pseudo low-pass filter, is the tilt angle signal θ, as is well known from Japanese Patent Laid-Open No. 4-168314. That is, it is almost equivalent to the high frequency component signal of. Other configurations are the same as those in FIG.

Therefore, also in this configuration, the same operation and effect as in the previous embodiment can be obtained. That is, the working depth value signal from the working depth setting device 62 and the first low-pass filter 67.
Since the deviation signal E from the output signal of is not affected by the disturbance of the plowing depth feedback signal, even if the rear cover 13 suddenly jumps up due to a stump or the like, the disturbance of the finished plowing depth is eliminated, and accurate plowing depth control can be performed. It will be possible. Further, by inputting the angular velocity signal of the tilt angle through the pseudo low-pass filter, the tilt angle signal θ is equivalently obtained.
Is calculated, and the difference signal between the deviation signal E and the equivalent high-frequency component signal of the tilt angle signal θ is calculated. As a result, the responsiveness of the height correction of the work implement 7 is improved with respect to a rapid change in the inclination angle, so that the plowing depth accuracy can be improved. Further, on a slope having a long slope such that the inclination angle does not change, the signal of the angular velocity signal through the pseudo low-pass filter becomes 0, so that the deviation signal E cannot be corrected. Therefore, the plowing depth accuracy on the sloping ground is improved. Further, the signal of the angular velocity signal obtained in this embodiment through the pseudo low-pass filter is the angular velocity detector 64.
Since it does not include the accumulated error obtained by integrating the drift, offset, etc., a high-frequency component signal with a more accurate tilt angle can be detected. Further, since the number of control components is small, there is no signal delay and it is practical.

Next, a third embodiment will be described with reference to FIGS. 5 and 6 are a configuration block diagram and a control block diagram, respectively, and the same configurations as those in FIGS. 2 and 3 described in the previous embodiment are denoted by the same reference numerals and the description thereof is omitted here. In FIG. 5, a gain limit setter 69 is attached to the control unit 27. The gain limit setter 69 sets a limit value for the output value of the amplifier that amplifies the deviation signal E between the tilling depth value signal and the tilling depth feedback signal of the tilling depth setter 62, and is constituted by, for example, a potentiometer or the like. It The output signal of the gain limit setter 69 is input to the controller 27 via the A / D converter 26. In FIG. 6, a limiter 70 is provided at a stage after amplifying the deviation signal E, and the output signal of the limiter 70 is input to the solenoid valve drive unit 28. The limiter 70 has a limit value set by the gain limit setter 69, and when the signal obtained by amplifying the deviation signal E becomes larger than this limit value, the limit value is output as an output signal. .

In such a structure, the working depth detector 63
When a sudden disturbance occurs in the plowing depth feedback signal from and the deviation signal E fluctuates greatly, the limiter 70 suppresses the amplified signal to below the limit value. As a result, the magnitude of the command signal to the solenoid valve drive unit 28 is suppressed, so that the lifting speed of the lift arm cylinder 4 is limited, and the working machine 7 does not lift more than necessary. Therefore, the stump or the like when the working depth is detected by the rotation angle of the rear cover 13 or the reference laser light when the working depth is detected by the relative position between the light receiving position of the reference laser light and the working machine 7 is used. The influence of a large disturbance of the plowing depth feedback signal due to a sudden shake is suppressed. As a result, the finished plowing depth value can be stabilized even if a sudden disturbance occurs.

[Brief description of drawings]

FIG. 1 is a side view of an earthmoving vehicle equipped with a tilling depth control device according to the present invention.

FIG. 2 is a configuration block diagram of a first embodiment according to the present invention.

FIG. 3 is a control block diagram of the first embodiment according to the present invention.

FIG. 4 is a control block diagram of a second embodiment according to the present invention.

FIG. 5 is a configuration block diagram of a third embodiment according to the present invention.

FIG. 6 is a control block diagram of a third embodiment according to the present invention.

FIG. 7 is a side view of an earthmoving vehicle including a rear cover according to a conventional technique.

FIG. 8 is a control block diagram according to a conventional technique.

FIG. 9 is a side view of an earthmoving vehicle including a light receiver for receiving a reference laser beam according to a conventional technique.

FIG. 10 is a side view of an earthmoving vehicle including a vehicle body inclination angle detector according to a conventional technique.

FIG. 11 is an explanatory view of problems of the tilling depth control device according to the related art.

FIG. 12 is an explanatory diagram of a problem of the tilling depth control device according to the related art.

[Explanation of symbols]

1 ... Earthwork vehicle, 2, 3 ... Wheel, 4 ... Lift arm cylinder, 5 ... Upper link, 6 ... Lower link, 7 ... Working machine, 8 ... Lift rod, 9 ... Steering handle,
10 ... Panel, 11 ... Lift arm, 12 ... Arm, 1
3 ... Rear cover, 15 ... Inclination angle sensor, 16 ... Angle sensor, 26 ... A / D conversion part, 27 ... Control part, 28 ... Electromagnetic valve drive part, 31 ... Tank, 32 ... Hydraulic pump, 33 ... Switching valve, 42 , 43, 45 ... Pipe line, 51 ... Laser projector,
52 ... Laser receiver, 53 ... Reference laser light, 55 ... Controller, 62 ... Plowing depth setting device, 63 ... Plowing depth detector, 64
... angular velocity detector, 65 ... integrator, 66 ... high-pass filter, 67 ... low-pass filter, 68 ... low-pass filter, 69 ... gain limit setter, 70 ... limiter.

Claims (7)

[Claims] 1. A working machine (7) provided at the rear end of an earthmoving vehicle (1) so as to be able to move up and down, and a working depth detector (63) for detecting the tilling depth (working depth) of the working machine (7). ), The working depth setting device (62) for setting the target working depth value, and the working depth value and the working depth detector of the working depth setting device (62).
In the working machine tillage depth control device of the earthmoving vehicle equipped with the controller (55) for controlling the raising and lowering of the working implement (7) so that the deviation from the detection value of (63) becomes small, the tiller depth detector (63) A first low-pass filter (67) that outputs a low-frequency component signal of the detected value, a tilt angle high-frequency component detection means that detects a high-frequency component signal of the tilt angle of the earthmoving vehicle (1) in the longitudinal direction, and a plowing depth setting device. The working depth of (62) and the first low-pass filter (67)
A controller (55) for correcting the deviation signal (E) from the output value of the work angle (E) by correcting the deviation signal (E) by the output value of the inclination angle high frequency component detecting means so that the deviation signal (E) becomes small.
A working machine tillage depth control device for an earthmoving vehicle, comprising: 2. The working machine tillage depth control apparatus for an earthmoving vehicle according to claim 1, wherein the inclination angle high frequency component detecting means detects an angular velocity detector (64) for detecting an inclination angular velocity of the earthmoving vehicle (1) in a front-rear direction. And a second low-pass filter (68) equivalently outputting a high-frequency component signal of the tilt angle by outputting a low-frequency component signal of the output signal of the angular velocity detector (64). Work machine tillage depth control device for earthmoving vehicles. 3. The working machine tillage depth control device for an earthmoving vehicle according to claim 1, wherein the inclination angle high frequency component detecting means detects an angular velocity detector (64) for detecting an inclination angular velocity of the earthmoving vehicle (1) in a front-rear direction. And an integrator (6 that integrates the angular velocity signal from the angular velocity detector (64).
A working machine tillage depth control device for an earthmoving vehicle, comprising: 5) and a high-pass filter (66) that outputs a high-frequency component signal of the output signal of the integrator (65). 4. The working machine tillage depth control device for an earthmoving vehicle according to claim 1, 2 or 3, wherein the tilling depth detector (63) controls a turning angle of a rear cover (13) of the working machine (7). A working machine tillage depth control device for an earthmoving vehicle characterized by being detected. 5. The working machine tillage depth control device for an earthmoving vehicle according to claim 1, 2 or 3, wherein the tilling depth detector (63) is a laser receiver (52) attached to the working machine (7). ) Is used to detect the relative position of the reference laser beam (53) and the working machine (7), and a working machine tilling depth control device for an earthmoving vehicle. 6. A working machine (7) provided at the rear end of the earthmoving vehicle (1) so as to be able to move up and down, and a tilling depth detector (63) for detecting the tilling depth (cultivating depth) of the working machine (7). ), The working depth setting device (62) for setting the target working depth value, and the working depth value and the working depth detector of the working depth setting device (62).
Based on this deviation so that the deviation from the detection value of (63) becomes small, the controller (5
In the working machine tillage depth control device for an earthmoving vehicle equipped with 5), the controller (55), when the deviation becomes larger than a limit value of a predetermined size, considers this limit value as a deviation, and based on the limit value. And a working machine tilling depth control device for an earthmoving vehicle, which outputs a lifting command for the working machine (7). 7. The working machine tillage depth control device for an earthmoving vehicle according to claim 6, wherein the limit value can be set arbitrarily.