JPH1028408A - Laser leveling device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress the laser detection error when the height of the light receiving device of a laser receiving device changes every moment due to the inclination of a work machine and to secure the uniformity of a field. SOLUTION: A vertical detectable region when a photodetector 38 of a laser light receiving device is in a vertical state is defined as L, and a region C including a diode 40a at a center position and diodes above and below the central position is defined as a dead zone. . When the light receiver 38 is tilted, the detectable area and the dead zone are narrowed, so the setting of the dead zone is temporarily changed according to the tilt of the work equipment, and the width of the dead zone is widened to prevent hunting of the work equipment. I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser leveling apparatus, and more particularly to a laser leveling apparatus which suppresses a laser detection error due to a tilt of a working machine.

[0002]

2. Description of the Related Art In recent years,
Large-scale fields are being developed to reduce the cost of agriculture. For this reason, in the conventional work of only controlling the depth by the rear cover or the work relying on the intuition of the operator,
The levelness of the field cannot be secured. A laser leveling device is known as a method for obtaining levelness in a field.

The laser leveling device radiates a laser beam in a horizontal direction at a certain height on a field scene and performs an operation based on a horizontal plane created by the laser beam. The machine is installed on the upper part of the work machine, the lift arm of the tractor is rotated according to the relative position of the laser light and the work machine, the position of the work machine is automatically adjusted, and the finished surface of the field is leveled. .

[0004] Since the light receiver is held at a high position by setting a mast on the work machine so as not to be in the shadow of the tractor, when the tractor rolls left and right, the mast is tilted accordingly, and the height of the light receiver is raised. Changes every moment and a laser detection error occurs.

An apparatus for controlling the position of a working machine by receiving a reference laser beam by a laser receiver is disclosed in Japanese Patent Application Laid-Open No. 58-1 / 1983.
No. 37013 is known. The device disclosed in the publication detects the inclination angle of the vehicle body to determine a height error of the light receiver, and calculates a control amount for correcting the position of the work implement based on the height error. However, the complexity of this calculation increases the cost of the device.

Therefore, when the height of the light receiving device of the laser receiving device changes every moment due to the inclination of the working machine, there is a technical problem to be solved in order to suppress the laser detection error and to secure the levelness of the field. The present invention aims to solve this problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object, and has a laser light receiving device capable of receiving a laser beam emitted in the horizontal direction and detecting the height of a working machine. Installing the light receiver of the laser receiving device above the work implement, rotating the lift arm of the tractor according to the relative position of the laser light and the work implement, automatically adjusting the position of the work implement and finishing the field in the field. An object of the present invention is to provide a laser leveling device that performs leveling control and that switches the width of a dead zone of the laser receiving device according to the inclination of a working machine.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a tractor 10, and a rotary working machine 12 is connected to a rear part of the body via a link mechanism 11. A controller 14 is located near the driver's seat 13.
The controller 14 is provided with a position lever 15, a cultivation depth setting dial 16, a laser changeover switch 17, and the like to set the cultivation depth of the rotary working machine 12. A slope sensor 18, a vehicle speed sensor 19, and the like are provided below the driver's seat 13.

The link mechanism 11 is of a three-point link type comprising a top link 20 and left and right lower links 21.
Are connected by a lift rod 23 and the lift arm 22 is rotated, whereby the lower link 21 moves up and down, and the rotary work machine 12 moves up and down. The rotation angle of the lift arm 22 is detected by a lift arm sensor 24.

A rolling cylinder 25 is provided in the middle of one of the right and left lift rods 23, and the rolling cylinder 25 is expanded and contracted to change the lift amount of the lower link 21 between the left and right sides. 12 is tilted left and right so that the rolling adjustment of the rotary work machine 12 can be performed.

On the other hand, a rear cover 27 is rotatably attached to the rear end of the main cover 26 of the rotary work machine 12 so that the depth sensor 28 detects the rotation angle of the rear cover 27 so that the depth of the rotary work machine 12 can be adjusted. Configure.

At this time, brackets 29 are fixed to the left and right positions of the main cover 26, the upper portions of the pressure rods 30 are mounted on the respective brackets 29, and the lower ends of the pressure rods 30 are connected to the brackets 31 of the rear cover 27. . Then, a spring 3 is attached to the pressure rod 30.
The rear cover 27 is interposed to restrict the movement of the rear cover 27, thereby preventing the rear cover 27 from jumping up.
The main cover 26 is formed so as to be rotatable back and forth around a rotation axis 34 of the tilling claw 33 in an arc-shaped locus.

FIG. 2 is a rear view of the rotary working machine 12, in which components such as the depth sensor 28 and the pressure rod 30 are omitted for convenience of explanation. As shown in FIGS. 1 and 2, a sensor mast 36 is erected on the main beam 35 of the rotary working machine 12. The sensor mast 36 is vertically expandable and contractable, and a bracket 37 at the base end thereof is fixed to the main beam 35 by bolting. A light receiver 38 of a laser receiving device is mounted on the upper end of the sensor mast 35, and an inclination sensor 39 is provided in the middle of the sensor mast 35.

In the embodiment of the present invention, the sensor mast 3
6 is mounted on the main beam 35 and on an extension of the lower link 21a on the side (left side) where the rolling cylinder 25 is not mounted, but is not particularly limited to this position. The work machine 12 may be attached to another position. Further, the mounting position of the inclination sensor 39 is not limited to the middle of the sensor mast 35, and may be mounted on the main beam 35 or another position of the rotary working machine 12.

[0015] As shown in FIG.
Are provided with a plurality of diodes 40 in a vertical direction, and a laser beam emitted from a projector described later is captured by any of the diodes. At this time, when the laser light is captured by the diode 40a at the center position of the light receiver 38, the rotary work machine 12 outputs the detection signal from the light receiver 38 on the assumption that the laser light is at the reference height. Also, the light receiver 38
When the laser beam is captured by a diode disposed either above or below the center position of the rotary work machine, it is determined that the rotary work machine 12 is at a high position or a low position with respect to the reference height, and the height difference with respect to the reference height is detected. Output from the detector 38 as a detection signal.

This detection signal is input to the controller 14, and when the rotary working machine 12 is at the reference height,
A control signal for raising and lowering the lift arm 22 of the link mechanism 11 is not output. On the other hand, when the rotary work machine 12 is at the high position with respect to the reference height, a control signal is output so as to lower the lift arm 22, while the rotary work machine 12 is at the low position with respect to the reference height. If so, a control signal is output so as to raise the lift arm 22.

Further, as shown in FIG.
Assuming that the detectable area in the vertical direction of 8 is L, an appropriate area C including the diode 40a at the center position and the diodes above and below it is set as a dead zone, and when the laser light is received in this area C, the controller 14 No control signal for raising and lowering the arm 22 is output. This is because when the light receiver 38 moves up and down finely due to the vibration of the rotary work machine 12 or the like, hunting occurs in the rotary work machine 12 when the lift arm 22 is moved up and down each time. This is to prevent roughening.

FIG. 4 shows a positional relationship between a laser light emitter and a laser light receiver. A stand 42 is installed on a ridge 41 of a field, and a light emitter 43 is attached to an upper end of the stand 42.
Laser light is emitted from the light projector 41 in the horizontal direction at a certain height on the field scene. The laser light is received by the light receiver 38, and the relative position between the laser light and the rotary work machine 12 is detected.

Here, adjustment of the tractor 10 is performed prior to laser beam irradiation. First, the link mechanism 11 is manually operated by the position lever 15 shown in FIG.
The height of the rotary working machine 12 is adjusted to determine the plowing depth. Subsequently, the sensor mast 36 is raised and lowered, and the
The vertical position of the light receiver 38 is adjusted so that the laser light is captured by the diode 40a located at the center position of the light receiver 38. After that, the switch of the projector 43 is turned on to irradiate the laser beam, and the operator lowers the position lever 15 a little to start the operation by the laser leveling device.

The light receiver 38 receives a laser beam emitted from the light projector 43 and outputs a detection signal.
In step 4, the height of the rotary working machine 12 is calculated. Then, the rotation angle of the lift arm 22 is adjusted in accordance with the height of the rotary work machine 12, and control is performed so that the plowing depth of the rotary work machine 12 is kept constant with reference to the laser light irradiation surface. Thereafter, the sensor mast 36 is slightly moved up and down in view of the finished condition of the tilling soil surface, and the vertical position of the light receiver 38 is readjusted.

As described above, a dead zone is provided in the light receiver 38. However, when the sensor mast 36 is inclined due to unevenness in the field, vibration of the rotary work machine 12, or the like, the width of the dead zone becomes narrow. For example, as shown in FIG.
When the photodetector 38 whose detectable area is L is inclined at an angle θ, the detectable area in the vertical direction becomes short as (L × cos θ) and the dead zone becomes narrow as (C × cos θ).

If the width of the dead zone becomes narrower every time the sensor mast 36 instantaneously tilts, hunting occurs in the rotary working machine 12.
When the inclination of 6 is detected, the setting of the dead zone is temporarily switched by an instruction from the controller 14 to increase the width. The setting of the dead zone is changed according to the inclination angle of the sensor mast 36.

That is, when the rotary working machine 12 is inclined, the width of the dead zone is temporarily changed.
When the inclination of 2 continues, the rolling cylinder 25 is driven to return to the horizontal position. The control for switching the setting of the dead zone in this manner is simpler in calculation than the conventional control for correcting the correction amount of the work implement according to the height error, so that the apparatus can be formed at low cost.

Here, the light emitter 43 has a laser emitting unit attached to a rotating body provided therein, and emits laser light while rotating in the horizontal direction. Therefore, the light receiver 38 does not receive the laser light continuously, but receives the laser light only when the laser light rotates and irradiates the light receiver 38. That is, the light receiver 38 receives the laser light in a pulsed manner. For example, the rotation speed of the light projector 43 is 300
When the rotation is performed, the light receiver 38 receives the laser light pulse five times per second, and the pulse cycle time is 0.2 second.

If another tractor uses a laser leveling device in a nearby field, and the photodetector 38 of the laser receiving device receives laser light from the nearby field, it becomes a disturbance and becomes a laser leveling device. Causes malfunction. Therefore, the rotation speed of the light projector 43 is made switchable by a dip switch or the like, so that the operator can select a cycle time of the laser light pulse from a plurality of set times.

For example, as shown in Table 1, by switching the dip switch from to, the rotation speed of the projector 43 is changed from 300 rpm to 600 rpm, and the cycle time of the pulse is changed from 0.2 seconds to 0.1 seconds. Can be set in four stages.

[0027]

[Table 1]

Therefore, if a cycle time different from the laser light used in the near field is selected and the dip switches of the light emitter 43 and the light receiver 38 are switched, the light receiver 38 of the laser light receiving device will cause the laser light from the nearby field to change. Since the cycle time is different even when receiving light, this floodlight 4
Only the laser light emitted from 3 is detected as the reference light,
Normal laser leveling control is performed.

FIG. 5 is a block diagram of the laser leveling device. The setting signals of the position lever 15, the tillage setting dial 16, the laser switch 17, etc.
Is input to The laser changeover switch 17 is a switch for switching between "laser leveling control" and "depth control by the rear cover". When "laser leveling control" is set, the rotary work machine 12 is controlled based on a horizontal plane generated by laser light. When the operation is performed by automatically adjusting the position, and the depth control is performed by the rear cover, the angle of the rear cover is read and the normal depth control is performed.

The sensitivity of the rolling control is changed between "laser leveling control" and "depth control by rear cover". That is, by switching the on-delay time from when the inclination is detected to when the rolling cylinder 25 is driven, or by switching the width of the dead zone when the inclination is detected, the rolling control at the laser leveling control and the rear cover Rolling control during depth control can be set independently.

Further, if the laser changeover switch 17 is switched to the "running" position after the completion of the plowing operation, the tractor 1
0 is the running mode. Further, detection signals from the slope sensor 18, the vehicle speed sensor 19, the lift arm sensor 24, the depth sensor 28, the inclination sensor 39, and the like are also input to the controller 14.

On the other hand, the laser beam emitted from the light projector 43 is received by the light receiver 38, and the height difference from the reference height of the rotary working machine 12 is input to the controller 14 as a detection signal. When the “laser leveling control” is performed, the controller 14 calculates the height of the rotary working machine 12 based on the detection signal from the light receiver 38 and outputs the laser light to the light receiver 3.
8, the control signal is output to the solenoid valve to drive the lift cylinder 44 in accordance with the height difference from the reference height, and the lift arm 22 is rotated to set the position of the rotary work machine 12. adjust. Further, a control signal is output to the solenoid valve to extend and contract the rolling cylinder 25 based on the detection value of the inclination sensor 39, and the rolling adjustment of the rotary work machine 12 is performed.

FIG. 6 shows a state in which the tractor 10 is rolling to the left, and at this time, the rotary working machine 12 is also inclined to the left as shown by a two-dot chain line. Then, by the rolling control, the rolling cylinder 25 is extended to lower the position of the lower link 21b on the right side, and the rotary work machine 12 is returned to the horizontal state as shown by the solid line.

FIG. 7 shows a state in which the tractor 10 is rolling rightward, and at this time, the rotary working machine 12 is also inclined rightward as shown by a two-dot chain line. Then, by the rolling control, the rolling cylinder 25 is contracted to raise the position of the lower link 21b on the right side, and the rotary working machine 12 is returned to the horizontal state as shown by the solid line.

As described above, when performing the rolling control, the height of the left lower link 21a is substantially constant, and the height of the right lower link 21b moves up and down. As described above, since the sensor mast 36 is attached to the main beam 35 on the extension of the lower link 21a on the left side,
Rotary work machine 1 by contraction of rolling cylinder 25
When returning 2 horizontally, the base end of the sensor mast 36 hardly moves up and down. Thus, the sensor mast 36 is swung to the left and right around the bracket 37, the height of the light receiver 38 is displaced by [Delta] H ₁ or [Delta] H _2.

On the other hand, when the sensor mast 36 is mounted at another position, for example, when the bracket 37 is fixed to the right side of the main beam 35 as shown in FIG.
When the rotary work machine 12 is returned to the horizontal state by the rolling control, the vertical movement of the bracket 37 increases as the distance from the left lower link 21a increases. Therefore, the displacement of the height of the light receiver 38 is ΔH ₃ or ΔH ₃
H _4, and the said [Delta] H ₁ or larger for laser detection error than [Delta] H ₂ becomes larger.

FIG. 9 shows a state in which the sensor mast 36 is stored. A hinge 46 is provided on the back side of the lower mast portion 45 to connect the upper mast portion 47, and the sensor mast 36 is moved backward at an intermediate portion of the mast 36 (FIG. To the right). Then, the lower mast section 45 and the upper mast section 4
7 and plates 48 and 49, respectively, are fixed.
A direct-acting actuator 50 is mounted between 8, 49.
Although a linear motor is used for the actuator 50, a hydraulic cylinder or the like may be used as long as it linearly expands and contracts. Note that a tension coil spring 51 is interposed diagonally behind the hinge pin 46a to urge the upper mast portion 47 clockwise in the drawing.

The laser switch 17 described with reference to FIG.
Is switched to the “running” position, the actuator 50 contracts according to a command from the controller 14,
As shown in FIG. 9, the mast upper section 47 is turned backward, and the sensor mast 36 is folded. That is, the tractor 10
When the vehicle travels, the sensor mast 36 automatically enters the housed state.

On the other hand, when the laser changeover switch 17 is switched to "laser leveling control", the actuator 50 is extended by a command from the controller 14 to push up the mast upper portion 47, so that the mast is pivoted around the hinge pin 46a. The upper part 47 rotates upward, and the sensor mast 36 stands up as shown by a two-dot chain line in FIG. At this time, since the upper end of the extension coil spring 51 moves obliquely forward of the hinge pin 46a beyond the dead center,
Is urged in the counterclockwise direction in the figure to maintain the upright state.

Subsequently, as shown in FIG. 10, the actuator 50 further extends, and the mast upper portion 47 slides upward from the slide portion 52. Assuming that the vertical stroke of the slide portion 52 is S, when the laser changeover switch 17 is switched to “laser leveling control”, the mast upper portion 47 slides to １ ／ of the vertical stroke, and the light receiver 38 is turned on. to rise to the position of the P _C.

The amount of expansion and contraction of the actuator 50 is detected by an internal potentiometer. If ask stretch to the slide portion 52 of the actuator 50 full stroke is, the photodetector 38 is susceptible elevating from the lowermost position P ₁ to the uppermost position P _2, at the time of initial adjustment of the laser beam automatically the light receiver 38 and the position of the P _C, a sufficient vertical range of adjustment of the photodetector 38 with simplified laser light adjustment work.

[0042] Then, when the laser switch 17 is switched to the "depth control by the rear cover", the actuator 50 is contracted mast upper part 47 is slid downward, the light receiver 38 to the lowest position P ₁ As it descends, the height of the aircraft can be kept to a minimum. Further, when the laser changeover switch 17 is switched to the "running" position, the sensor mast 36 is folded and stored as described above with reference to FIG. Alternatively, when the laser switch 17 is switched from "laser Hitoshitaira control" to the "running" position and held in a state of lowering the light receiver 38 to the lowest position P _1, so as to run the tractor 10 It may be.

The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

[0044]

As described above, according to the present invention, the width of the dead zone of the laser receiving device is switched according to the inclination of the work machine, so that hunting of the work machine can be prevented when the work machine is instantaneously inclined.

Thus, the laser detection error due to the tilt and vibration of the working machine can be reduced, and the levelness of the field can be ensured.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a side view of a tractor provided with a laser leveling device and a rotary working machine.

FIG. 2 is a rear view of a tractor provided with a laser leveling device and a rotary working machine.

FIG. 3A is a front view of the light receiver in a vertical state. (A) Front view of the light receiver in an inclined state.

FIG. 4 is an explanatory diagram showing a positional relationship between a laser projector and a photodetector.

FIG. 5 is a block diagram of a laser leveling device.

FIG. 6 is a diagram showing a height displacement of a light receiver when the tractor rolls to the left.

FIG. 7 is a diagram showing a height displacement of a light receiver when a tractor rolls to the right.

FIG. 8 is a diagram illustrating a height displacement of a light receiver during rolling when a mounting position of a sensor mast is changed.

FIG. 9 is a side view of the sensor mast in a housed state.

FIG. 10 is a side view of the sensor mast in an upright state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tractor 12 Rotary work machine 22 Lift arm 38 Light receiver 40 Diode 43 Floodlight L Detectable area C Dead zone area

Claims (1)

[Claims] 1. A laser light receiving device capable of detecting the height of a working machine by receiving laser light radiated in a horizontal direction is provided, and a light receiving device of the laser receiving device is installed on an upper part of the working machine. A lift arm of a tractor is rotated in accordance with the relative position of the tractor, and the position of the work machine is automatically adjusted to level the finished surface of the field. A laser leveling device characterized by switching a width of a dead zone of a light receiving device.