JP3115274B2 - Attitude control device for agricultural work machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining a horizontal posture of a working machine such as a seedling planting machine (rolling posture control) in a farming machine such as a rice transplanter for planting seedlings in a field, and for controlling the front and rear of the working machine. Maintain horizontal attitude (pitching attitude control)
The present invention relates to a posture control device for performing the operation.

[0002]

2. Description of the Related Art Conventionally, when planting seedlings in a field using a riding type rice transplanter, a seedling plant is mounted on the front or rear part of the traveling machine so as to be able to turn left and right and back and forth. ,
Planting mechanisms are provided at appropriate intervals on the left and right in the traveling direction, and the seedling mats on the seedling mounting table in the seedling plant are divided by the number of plants as appropriate by the planting mechanism that rotates up and down as the rice transplanter advances, and is planted in the field scene. For example, Japanese Patent Application Laid-Open No. 2-135015 and Japanese Patent Publication No. 57-27
No. 682, which is disclosed in Japanese Patent Application Laid-Open No. 2-135.
In the publication No. 015, a detection signal of a ground pressure sensor provided between a seedling plant and a float below the seedling plant is used as a detecting means in a control (rolling control) for maintaining a horizontal orientation of the seedling plant. It is disclosed.

In Japanese Patent Publication No. 57-27682,
Detection of a tilt angle sensor for detecting a tilt angle of an object to be measured with respect to a horizontal line or a vertical line in a posture control (pitching control) for maintaining a substantially horizontal posture so as to eliminate the front-back tilt posture of the seedling planting device. The use of signals is disclosed. However, with this kind of tilt angle sensor alone, it is not possible to accurately grasp the degree of posture variation of the seedling plant, and there are inconveniences such as a delay in posture control. In Japanese Unexamined Patent Publication No. Hei 4-104713, a seedling plant is
It has been proposed to provide an angular velocity sensor capable of detecting the velocity of the inclination and an inclination angle sensor.

[0004]

Considering the case of the rolling control (right and left inclination control) of the seedling plant, the seedling plant can be rotated left and right by the traveling machine body via a linking mechanism such as a link mechanism. And a traveling device such as a wheel of a traveling body is grounded to a cultivator in a field, and the seedling is floating on a mud surface on the cultivator. Takes a horizontal posture without tilting left and right with respect to the mud surface.

[0005] When the seedling plant is towed or pushed forward by the traveling machine, and moves forward, when the wheels or the like of the traveling machine climb or fall on the uneven cultivator,
The traveling body first tilts left and right, and then the right and left tilting posture of the seedling-planting device changes via the connection mechanism. In order to restore the changed posture to the original horizontal posture, the posture is adjusted by driving means such as a hydraulic cylinder provided between the connection mechanism and the seedling plant.

[0006] In this case, when the angular velocity sensor 58 and the inclination angle sensor are mounted on a seedling plant that is the same object to be measured and that is an object to be posture-controlled, as in the prior art,
The control algorithm (control rule) is complicated for the following reasons. That is, the state in which the inclination angle of the seedling plant is increased with respect to the horizontal line is detected by the inclination angle sensor. That is, the detection value of the inclination angle sensor is “0” with respect to the horizontal state of the seedling plant and the inclination angle is As you grow up,
The detected value becomes large (lower right slope) with a positive value, and large (lower left slope) with a negative value.

On the other hand, since the seedling plant swings right and left with the horizontal state being the center of vibration, and the posture is controlled so as to maintain the horizontal state, the angular velocity of the seedling device is:
In the horizontal state, and at the time of reversal of swinging in the opposite direction after tilting to the left and right, it becomes “0”, and the angular velocity is large in the intermediate state (for example, a positive value for the downward rightward movement state, a negative value for the downward leftward movement state Value).

Further, since the angular velocity at the time of the restoration is detected by the angular velocity sensor in accordance with the movement of the seedling plant to be restored, the result of the detected value of the angular velocity sensor alone indicates that the angular velocity of the plow in the field is small. It is impossible to determine whether it is due to unevenness or when restoring. In addition,
In the tilt angle sensor, a detected value can be uniquely determined as a tilt angle with respect to a horizontal state, and the detected value can be generally used as a feedback amount of a control system, but the detected value of the angular velocity cannot be a feedback amount. .

Therefore, in order to consider the influence of the magnitude of the angular velocity on the magnitude of the inclination angle, the control algorithm (control rule) must be determined by a combination of the magnitude of the two detected values. The solution would have to adopt something like fuzzy inference. Also, as described above, the seedling plant is tilted left and right via the connecting mechanism after the traveling body is tilted left and right, and then the seedling plant is restored from the tilted state although the traveling body is restored to the horizontal state. For example, there is a time lag between the part causing the left-right inclination and the object to be attitude-controlled, and the angular velocity detects the tendency of the motion state of the part causing the left-right inclination. Suitable for. In other words, there is a problem that even if an angular velocity sensor is attached to the seedling device that is the object to be measured and is the object of posture control and the result is known, the time lag is not eliminated.

Further, there is a remarkable difference in response as a detection characteristic between the inclination angle sensor and the angular velocity sensor. That is, since the angular velocity sensor detects the inclination velocity of the object to be measured, its response is on the order of several milliseconds. When the response is slow, the instantaneous displacement velocity cannot be measured.
It is useless as an angular velocity sensor. On the other hand, if the inclination angle sensor can detect an extremely small inclination displacement, if the attitude is controlled in accordance with the detected value, the hunting phenomenon or the like may occur. It is in milliseconds.

As described above, if signals from two types of sensors having remarkably different responsiveness are simultaneously processed by the control means as information of the same time, the following inconvenience occurs. That is, as described above, since the detection responsiveness of the inclination angle sensor is slower than that of the angular velocity sensor, a discrepancy due to a contradiction caused by assuming that the detection values of the two are at the same time becomes remarkable, and the control calculation is performed. The result is far from the entity and unreliable.

Such a problem is caused not only by the rice transplanter,
It also occurs in a tractor for plowing a field and a tilling device (working machine) towed by the tractor. Therefore,
An object of the present invention is to improve the control accuracy by solving the above-mentioned problem in this kind of agricultural working machine. In addition, since the agricultural work machine is operated outdoors, the sensors mounted thereon are also easily wetted by rain and may be damaged by hitting an external object. The present invention also aims to prevent this.

[0013]

In order to achieve the above-mentioned object, an attitude control device for an agricultural work machine according to the present invention comprises a work machine mounted on a traveling machine so as to be able to turn left and right and / or back and forth. While the machine is provided with an inclination angle sensor for detecting the degree of change in the attitude of the work machine, an angular velocity sensor for detecting the inclination speed of the aircraft is provided below the pilot seat in the traveling aircraft, The posture of the working machine is controlled by an actuator according to the detection values of these two sensors.

[0014]

According to this structure, as described above, the working machine such as the seedling plant tilts left and right (front and rear) via the connecting mechanism after the traveling body is tilted left and right and the like. There is a time lag between the part causing the left-right inclination or forward-backward inclination and the object to be posture-controlled, such as the seedling plant not returning from the inclined state even though the traveling body is restored to the horizontal state. For some controls, by providing an angular velocity sensor with a large fluctuation in the detection value on the traveling machine side, which is the side that causes the tilt of the work machine, it is possible to quickly obtain the detection value for attitude control of the work machine Can be.

[0015] The work machine, which is the object to be controlled, is provided with a tilt angle sensor for detecting its tilt state.
By providing the angular velocity sensor on the traveling body side, it is possible to detect the tendency of the movement state of the part causing the left-right (front-back) inclination, and not to detect the movement state of the work machine, which is the control object, when restoring the posture. In addition, by separately detecting,
The algorithm of the attitude control can be simplified. As a result, there is an effect that the accuracy of the attitude control is improved and smooth control can be realized.

Further, since the angular velocity sensor is disposed below the control seat of the traveling body, it is possible to prevent rainwater from being interrupted by the control seat when working outdoors and to directly wet the angular velocity sensor. Is large and rugged enough for a worker to sit on, and by arranging an angular velocity sensor below it, it is possible to block direct collision of external obstacles. This has the effect that damage can be effectively prevented.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment applied to a rice transplanter will be described.
The traveling body 1 comprises a body frame 2, front wheels 3, 3 attached to the front side thereof, and rear wheels 5, 5 attached to the rear side via swing cases 4, 4 which can be turned up and down. A steering seat 6 and a steering handle 7 are provided on the upper surface of the body frame 2, and the driving force of the engine 8 on the front upper surface of the body frame 2 is
In this configuration, the rear wheels 5 are driven via the speed change mechanism in the power transmission unit case 9 and the swing cases 4 and 4.

A parallel link mechanism 1 is provided at the rear of the traveling body 1.
The seedling transplanter 10 which can be vertically moved through the center 1 is mounted on a central transmission case 12 and on both left and right sides of the central transmission case 12 at appropriate intervals via a connecting pipe 12a having a transmission shaft inserted therein. Transmission cases 14 and 14 and a horizontally reciprocally movable seedling mounting table 1 that is inclined so that the upper end approaches the traveling machine body.
A seedling planting mechanism 16 for raising and lowering the planting claw between the seedling outlet at the lower end of the seedling mounting table 15 and the field scene 17 is provided on the left and right sides of the rear of the right and left planting transmission case 14. I have.

The parallel link mechanism 11 is driven up and down by the hydraulic cylinder 13 on the traveling machine body 1 side. The parallel link mechanism 11 includes a top link 18 and a pair of left and right lower links 19, 19. The base end of the top link 18 is pivotally connected to a portal frame standing on the vehicle body frame 2. A portal 20 to which each tip of the lower link 19, 19 is attached is rotatably connected to a rolling shaft 22 of a hitch 21 in the seedling plant 10, and the seed planting device 10 has a float 10a on its lower surface. The configuration is such that the running body 1 can be turned up and down (rolling) right and left around the rolling shaft 22 so as to slide in a field scene.

The guide portions 23, 23 projecting from the left and right planting transmission cases 14, 14 are slidably fitted on the rails 24 at the lower end of the rear surface of the seedling mounting table 15, while the upper portion of the rear surface of the seedling mounting table 15 is slidable. The guide rail 25 is provided with the right and left planting transmission case 14,
Roller part 2 at the upper end of a pair of columns 26 protruding from 14
7 and 27 are slidably fitted respectively. A horizontal reciprocating hydraulic cylinder 29, which is an actuator for rolling control, is fixed to a bracket 28 attached to the portal type support 20, and both ends of a piston rod 30 that can move left and right in the hydraulic cylinder 29 are connected to the pair of right and left supports. 26, 26 are rotatably mounted on a connecting rod 32 via a universal joint 31.

The power from the engine 8 is transmitted to the transmission mechanism in the power transmission unit case 9 via the main clutch 33 to drive the rear wheels 5 while being transmitted to the seedling plant 10 via the PTO shaft 34. Is done. Reference numeral 35 denotes an actuator for turning on and off the main clutch 33, 36 denotes an actuator for traveling speed change, and 37 denotes an actuator for traveling clutch.

A control valve 40 operable by the rotation of an arm 39 swinging back and forth which projects from a steering gear box 38 associated with the steering handle 7 includes a hydraulic circuit 41.
The steering arm 44 of the steering mechanism 43 connected to the swingable hydraulic cylinder 42 has a pivot fulcrum 4.
It is rotatable about five times, and the front wheels 3, 3 are connected by a pair of tie rods 46, 46 connected to the steering arm 44.
The electromagnetic solenoid control valve 47 in the hydraulic circuit 41 is for automatic steering control, and the reference numeral 48 is an electromagnetic solenoid control for the rolling (horizontal attitude) control. It is a valve.

Reference numeral 49 denotes a steering sensor comprising a potentiometer or the like provided at the rotation fulcrum 45 for detecting the steering angle of the traveling body, and outputs an output signal of the steering sensor 49 to a microcomputer or the like to be described later. It is input to the electronic control type control means 69. Reference numeral 51
Is a tilt angle sensor provided at an appropriate position of the seedling plant 10 in order to detect the left-right tilt angle of the working machine such as the seedling plant 10 with respect to the field scene. In the embodiment, as shown in FIGS. Since the inclination angle sensor 51 is fixed to the lower and middle part of the support 26 for supporting the seedling mounting table 15 on the lower surface side of the seedling mounting table 15 arranged in the backward inclination, rainwater from above is Can be prevented from getting wet by being blocked by the seedling mounting table 15. As shown in FIG. 6, the tilt angle sensor 51 is provided with a movable coil 55 having a pendulum 54 rotatable about a shaft 53 in a case 52, a bridge circuit including R0, R1, and R2, and a light emitting element. LED1 and LED
2, and a pair of left and right photocouplers of the light receiving elements PT1 and PT2 and an external power source E.

When the tilt angle sensor 51 is in the horizontal state, the light receiving amounts of the light receiving elements PT1 and PT2 are equal and the bridge circuit is balanced. When the tilt angle (θ1) is tilted, the pendulum 54
Remains in the direction of gravity (vertical direction), and the light blocking plate 5
At 4a, the light receiving of one of the light receiving elements PT1 is cut off, and the other light receiving element PT2 receives the light and turns on, the balance of the bridge circuit is lost, and the current flows to the movable coil 55, and the current causes the movable coil 55 to generate. When the rotational torque and the moment due to the weight of the pendulum 54 are balanced (θ2)
Then, the pendulum 54 stops, and the current value (I) at that time becomes an output signal, which is proportional to the inclination angle (θ1) (see FIG. 6).

Reference numeral 58 shown in FIG. 7 denotes a tuning fork vibration type (piezogyro type) angular velocity sensor.
Are provided at appropriate places on the traveling body 1, for example, at the left and right center positions of the traveling body 1 such as below the control seat 6. In the example,
As shown in FIGS. 1 and 2, an angular velocity sensor 58 is fixed below the control seat 6 and on a flat plate 2 a of the body frame 2 that supports the control seat 6. Accordingly, the angular velocity sensor 58 is provided between the flat plate 2 a and the control seat 6.
As a result, the cockpit 6 covers the angular velocity sensor 58 like an umbrella, preventing rainwater from getting wet from above, and an external obstacle collides with the angular velocity sensor 58. This can be prevented by the cockpit 6.

Next, the structure of the angular velocity sensor 58 will be described. The bottom of a drive element 59 composed of a piezoelectric bimorph and the monitor element 60 are connected by a connection block 61,
A tuning fork structure is formed by orthogonally coupling detection elements 62 and 63, each of which is also a piezoelectric bimorph, to the drive element 59 and the monitor element 60. When a voltage is applied only to the drive element 59 to vibrate, the connection is established. The monitor element 60 vibrates via the block 61. The vibration amplitude of the monitor element 60
The frequency of the driving vibration is stabilized by the vibration feedback control method of controlling the applied voltage by monitoring the phase.

In this stable state, the angular velocity sensor 5
8 has a rotational motion with an angular velocity ω about the sensor axis 64 in FIG. 7, a Coriolis force Fc is generated in a direction perpendicular to the vibration direction (XX direction) of the detection elements 62 and 63. Since a voltage corresponding to the bending can be detected from the driving element 59 and the detecting elements 62 and 63 on the monitor element 60 side which are bent by the Coriolis force, the angular velocity can be detected by this.

Reference numerals 66 and 67 denote the sensors 51 and 5 respectively.
8 is an A / D converter with an amplifying circuit provided corresponding to FIG. The control means 69 shown in FIG. 3 is a microcomputer including an 8-bit one-chip microprocessor or the like, which executes a program control for attitude control, and performs various operations.
And a read-only memory (ROM) for storing initial values and control programs in advance, and a read-write memory (RAM) for storing input signals and the like each time and outputting them at the time of calculation.
And an interface connected to the input / output unit.

Output signals from the sensors 51 and 58 and a signal from a clutch switch 70 linked to the switching operation of the traveling clutch are input to the input section of the interface. The output signal of the clutch switch 70 that operates in response to the operation of the travel clutch actuator 37 is turned on when the travel clutch is disengaged (stops traveling), and outputs an OFF signal when the travel clutch is engaged (during travel).

The output of the interface is connected to electromagnetic solenoids 71 and 72 of the control valve 47 for driving the hydraulic cylinder for the steering operation, as well as electromagnetic solenoids 73 and 74 for the control valve 48 for rolling control. . Next, an inclination angle sensor 51 serving as a posture control sensor
A control device and a control method related to the rolling posture control by the angular velocity sensor 58 will be described.

The control device uses the control means 69 such as the microcomputer, and adopts a software control method by a program in the microcomputer. First, the following tables [Table 1] and [Table 2] are stored in advance in the read-only memory (ROM).
From the combination of the detection value of the inclination angle sensor 51 and the detection value of the angular velocity sensor 58, the value of the drive command signal S for pulse driving the control valve 48 of the hydraulic cylinder 29 is calculated based on [Table 1] ( A search is performed, and the piston rod 30 of the hydraulic cylinder 29 is controlled to move as shown in [Table 2] based on the obtained value of S.

[0032]

[Table 1]

[0033]

[Table 2]

Table 1 above is a table showing the relationship of the drive command signal S to the control valve 48 of the hydraulic cylinder 29 for rolling control with respect to the combination of the detected value of the inclination angle and the detected value of the angular velocity. The value of the drive command signal S (−7 to 0)
-+ 7), the driving speed of the hydraulic cylinder increases as the numerical value increases, and the positive sign indicates that the seedling plant 10 is turned to the lower right direction (posture) in the traveling direction of the traveling machine. The minus sign (-, minus) indicates the case where the seedling plant 10 is turned leftward (the posture is corrected) in the traveling direction of the traveling machine body. [Table 2] shows the drive command signal S and the piston rod 3 of the hydraulic cylinder 29 provided at the place of the embodiment.
In the table showing the relationship with the moving speed of 0, the magnitude of the moving speed is set in accordance with the mounting position of the hydraulic cylinder 29 (the distance from the rolling rotation center of the seedling transplanter 10).

The grades in Table 1 are assigned corresponding to the input values (detection values) of the respective sensors. One grade of grade θ for the inclination angle sensor 51 is 0.22 degrees, and the grade for the angular velocity sensor 58 is One stage of V
0.8 degrees / second. Then, the median value (horizontal state) of the detection values of the inclination angle sensor 51 is that of grade 5, and when the grade θ value increases (toward the traveling direction), the inclination angle to the right decreases, and the grade θ A smaller value (in the direction of travel) indicates a larger leftward downslope angle. The median value of the detection values of the angular velocity sensor 58 (when the angular velocity is zero and in a stationary state) is a grade V value of 8,
When the angular velocity is in the counterclockwise direction in the traveling direction, the grade V value is smaller than 8, and the grade V value decreases as the detected value of the angular velocity in that direction increases. Conversely, the grade V value is greater than 8 when the angular velocity is clockwise in the traveling direction, and the grade V value increases as the detected angular velocity value in that direction increases.

As can be understood from Table 1, the grade V values corresponding to the angular velocities are (6), 7, 8, 9, (1)
0), that is, when the detected value of the angular velocity sensor is zero or within a predetermined value near the zero and the grade θ value corresponding to the inclination angle is in the range of 1 to 9, Set the value to "0" (stationary). This means that when the traveling body 1 is not tilted left and right or is tilted left and right at an extremely slow angular velocity, the tilted state is not forcibly corrected even if the seedling plant 10 is tilted to the left or right to some extent. This is because the stability of the posture correction sensor is rather improved.

The grade V corresponding to the angular velocity
When the value is 7 or 8 (the angular speed in the counterclockwise direction is zero or a small value) and the grade θ value corresponding to the inclination angle is 0 (the degree of descending to the left is large), the seedling plant is left at an extremely slow speed. Correct the posture in the up direction. Similarly, the grade V value corresponding to the angular velocity is 8, 9 (the clockwise angular velocity is zero or a small value), and the grade θ value corresponding to the inclination angle is 1
When the value is 0 (the degree of descending to the right is large), the posture of the seedling plant is corrected in the upward direction at an extremely low speed. in this way,
When the attitude control is performed according to the detected value of the tilt angle sensor and based on a gentle operation, the attitude correction control responsiveness is stabilized.

When the detected value of the angular velocity sensor is out of the range of the predetermined value (zero or small value), the attitude control is executed by giving priority to the detected value of the angular velocity sensor. For example, the degree of movement of the traveling body 1 to rotate counterclockwise becomes large (as the grade V value changes from 6 to 0, the size of the left-right inclination of the seedling plant 10 (grade θ corresponding to the inclination angle) The value is not so affected by 0 to 10), and the control for correcting the attitude is executed by giving priority to the magnitude and direction of the angular velocity.

As described above, when the movement of the traveling body 1 to tilt left and right is large, the traveling body which causes the inclination is smaller than the inclination angle of the seedling plant 10 itself rotatably connected to the traveling body. The response of the control is more stable if the posture of the seedling plant is controlled by the degree of movement (the magnitude and direction of the angular velocity). Moreover, when the response of the angular velocity sensor is significantly faster than the response of the inclination angle sensor, by utilizing the detection result of the angular velocity sensor provided on the traveling body that causes the inclination of the seedling plant, The response of the control becomes more and more stable.

The present invention can also be applied to the case where the pitching attitude control is executed by detecting the fluctuation of the longitudinal rotation attitude of the seedling plant using the tilt sensor and the angular velocity sensor.

[Brief description of the drawings]

FIG. 1 is a side view of a riding type rice transplanter.

FIG. 2 is a plan view of a riding type rice transplanter.

FIG. 3 is a side view of a main part of a connecting portion between the seedling plant and the traveling machine body.

FIG. 4 is an operation explanatory diagram including a block diagram of a control device and a hydraulic circuit.

FIG. 5 is a VV view of FIG. 3;

FIG. 6 is a block diagram of a tilt sensor.

FIG. 7 is a perspective view of an angular velocity sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Running body 3, 5 wheels 6 Steering seat 10 Seedling plant 15 Seedling table 16 Planting mechanism 11 Link mechanism 22 Rolling axis 51 Inclination sensor 58 Angular velocity sensor 69 Control means

Claims (1)

(57) [Claims] 1. A work machine can be rotated left and right on a traveling machine body.
A tilt angle sensor is attached to the work machine so as to detect the degree of change in the posture of the work machine, and the tilt speed of the machine is detected below a control seat in the traveling machine. An attitude control device for an agricultural work machine, wherein an angular velocity sensor is provided for the operation of the work machine and an actuator controls the attitude of the work machine in accordance with detection values of the two sensors.