JP2919044B2 - Left and right attitude control device in agricultural work machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a horizontal driving posture of a working machine such as a seedling plant in a farm work machine such as a rice transplanter for planting seedlings in a field or a traveling drive device. The present invention relates to an automatic horizontal attitude control device for maintaining a horizontal horizontal attitude of a traveling body capable of moving up and down with respect to a vehicle.

[Conventional technology]

Conventionally, when planting seedlings in a field by a riding type rice transplanter, a seedling planting device is mounted on the front or rear part of the traveling machine so as to be able to turn left and right and move up and down, and the seedling planting device is placed in the traveling direction left and right. A planting mechanism is provided at an appropriate interval, and the planting mechanism which rotates up and down as the rice transplanter advances advances so as to plant the seedling mats of the seedling mounting table in the seedling planting apparatus into the field scene while appropriately dividing the seedling mats by the number of plants. The fact is that, for example,
No. 104616 and Japanese Utility Model Application Laid-Open No. 1-109912, and in Japanese Utility Model Application Laid-Open No. 1-109912, image information from a video camera and a tilt sensor are used as detecting means for maintaining the horizontal orientation of the seedling planting device. U.S. Pat.

[Problems to be solved by the invention]

However, in the prior art, the imaging means has a two-dimensional plane in which the imaging screen has a horizontal and vertical spread like a so-called video camera, and the number of data of the image information is enormous and storage for that purpose is large. The capacity of the unit must be increased, and the calculation of image processing for obtaining predetermined data required for automatic control is complicated. There is a problem that it takes too much time from the result to the posture control.

In addition, the detection of the right and left inclination angles of the working machine by the inclination sensor has the following problems.

For example, it is assumed that a seedling plant is rotatably connected to a traveling machine at a hinge portion. When the seedling plant in the horizontal state tilts downward and to the right, the instantaneous center at the moment of the start of the tilt is estimated to be far below the field scene.

In this case, in the short time of the start of the inclination, the amount of rightward movement (rightward horizontal movement component) of the seedling plant moving rightward (vertical movement component) is larger than the amount of rightward downward movement (vertical movement component). Moreover, since the movement is started from the stationary state, the acceleration (acceleration variation rate) in the movement direction is large.

In addition, the tilt sensor is generally configured to detect a change in the angle of the pendulum having the property of constantly moving in the direction of gravity (vertical direction) with respect to the left and right tilt of the test object (the seedling plant in this case). And the inertial force of the pendulum itself (the property of a stationary object to maintain its state)
Therefore, when the seedling plant starts to move to the right,
The pendulum will be left relatively to the left.

Therefore, as shown in FIG. 17, when the actual inclination angle θ ′ of the work implement is indicated by a solid line (To is an inclination angle variation section), the output θ of the inclination sensor indicated by the dotted line is In the early stage of the start of the tilt, an output value in the direction opposite to the tilt direction is shown, and then an output value in the tilt direction of the work machine is shown, so that there is a reverse output section (T1) and a time delay of the output occurs. Therefore, the responsiveness that the inclination of the working machine is quickly detected is lacking.

On the other hand, as shown by the one-dot chain line in FIG. 17, in the speed sensor for detecting the speed or angular speed of the working machine when turning left and right, the output V of the speed sensor indicates the inclination moving speed at the beginning of the start of the working machine tilt. The value (magnitude) and its moving (tilt) direction
There is an advantage that detection can be performed in a state of good responsiveness.

An object of the present invention is to solve the above problem by utilizing this fact.

[Means for solving the problem]

In order to achieve this object, the present invention provides a traveling machine, in which a working machine is mounted to be rotatable left and right and up and down, and the working machine is placed in a horizontal state by an actuator interposed between the traveling machine and the working machine. In the agricultural work machine configured to execute the control to hold the work machine, the work machine has an inclination sensor for detecting a left-right inclination angle thereof, and a speed sensor for detecting a speed or an angular speed when the work machine is rotated left and right. And control means for obtaining a control output for the actuator based on the detection results of the two sensors.

〔The invention's effect〕

Although the tilt sensor can detect the absolute value of the tilt angle of the work implement, it has a disadvantage that it has a reverse output section in the initial section of the start of the tilt and a time delay of output. On the other hand, with a speed sensor that detects the speed or angular speed of the working machine when turning left and right, the value (magnitude) of the tilt moving speed and the direction of movement (tilt) of the working machine in the initial stage of the start of tilting are responsive. Although it can be detected, there is a drawback that the absolute value of the tilt angle of the work machine cannot be known.

Therefore, the present invention utilizes the detection results of these two sensors. In other words, in the initial section of the start of the tilting of the work machine, the speed of the tilting speed of the work machine and its direction are quickly detected from the detection result of the speed sensor, while the actual result of the work machine is detected by the detection result of the tilt sensor. By detecting the inclination angle, the disadvantages of the two can be compensated for each other, and the posture control of the working machine can be executed with good responsiveness and accurately.

As described above, when the inclination speed is considered in addition to the inclination angle, the situation and state of the left and right inclination of the working machine such as the seedling planting device can be accurately and quickly grasped, and the correction amount suitable for these situation and state can be finely determined. In addition, the calculation can be performed quickly, the posture control of the movement can be performed quickly and smoothly (not jerky), and the control accuracy can be improved and the smooth control can be realized.

〔Example〕

In the following, an embodiment applied to a rice transplanter will be described. In FIG. 1, reference numeral 1 denotes a traveling body, and the traveling body 1 includes a vehicle body frame 2, front wheels 3, 3 attached to a front side thereof, and a vertical rotation to a rear side. Rear wheels mounted via flexible swing cases 4,4
The control seat 6 is located on the upper surface of the body frame 2.
And a steering handle 7. The rear wheel 5 is driven by the driving force of the engine 8 on the entire upper surface of the body frame 2 via the speed change mechanism in the power transmission unit case 9 and the swing cases 4, 4.

A seedling device 10 attached to the rear part of the traveling machine body 1 so as to be vertically movable via a parallel link mechanism 11, a central transmission case 12,
On the left and right sides of this central transmission case 12, planted transmission cases 14, 14 attached at appropriate intervals via connecting pipes 12a with transmission shafts inserted, and horizontal reciprocating arrangement with the upper end inclined to the traveling machine A movable seedling mounting table 15 is provided, and on both left and right sides of the rear of the right and left planting transmission case 14, seedlings are provided in which a planting claw rises and falls between a seedling outlet at the lower end of the seedling mounting table 15 and a field scene 17. A mechanism 16 is provided.

The parallel link mechanism 11 is driven up and down by the hydraulic cylinder 13 on the traveling body 1 side.

The parallel link mechanism 11 includes a top link 18 and a pair of left and right lower links 19, 19, and the base end of the top link 18 is pivotally connected to a portal frame standing on the vehicle body frame 2 by a pin. The portal type strut 20 to which each tip of the lower link 19, 19 is attached is rotatably connected to the rolling shaft 22 of the hitch portion 21 in the seedling planting device 10, and the seedling planting device 10
In this configuration, the traveling body 1 can be turned up and down (rolling) right and left around the rolling shaft 22 so that the float 10a on the lower surface slides in the field scene.

Guide parts 23, 23 protruding from both right and left planted transmission cases 14, 14
On the other hand, the guide rail 25 on the upper rear surface of the seedling mounting table 15 is slidably fitted to the rail 24 at the lower rear end of the seedling mounting table 15. The rollers 26 are slidably fitted to the roller portions 27 at the upper ends thereof.

A bracket 28 attached to the portal 20 has a horizontal reciprocating hydraulic cylinder 29 serving as an actuator for rolling control.
Is fixed, and both ends of a piston rod 30 that can move left and right in the hydraulic cylinder 29 are rotatably mounted via a universal joint portion 31 to a connecting rod 32 that is attached to the pair of right and left columns 26 and 26.

The power from the engine 8 is transmitted to the transmission mechanism in the power transmission case 9 via the clutch 33 to drive the rear wheel 5 and is transmitted to the seedling plant 10 via the PTO shaft 34.

Reference numeral 35 denotes an actuator for turning on and off the clutch 33, 36 denotes an actuator for traveling speed change, and 37 denotes an actuator for PTO shaft speed change.

A control valve 40, which can be operated by rotation of an arm 39 that can swing back and forth and protrudes from a steering gear box 38 related to the steering handle 7, operates a hydraulic cylinder 42 in a hydraulic circuit 41. The steering arm 44 of the steering mechanism 43 connected to the hydraulic cylinder 42 is rotatable about a rotation fulcrum 45, and a pair of tie rods 46, 46 connected to the steering arm 44.
The other electromagnetic solenoid control valve 47 in the hydraulic circuit 41 is for automatic steering control, and reference numeral 48 is the rolling (horizontal attitude). ) An electromagnetic solenoid control valve for control.

Reference numeral 49 denotes a steering sensor including a potentiometer and the like provided at the rotation fulcrum 45 for detecting the steering angle of the traveling aircraft. An output signal of the steering sensor 49 is electronically controlled by a microcomputer or the like described later. Is input to the control means 50.

Reference numeral 51 denotes an inclination sensor provided at an appropriate position of the seedling plant 10 to detect a left-right inclination angle of the working machine such as the seedling plant 10 with respect to a field scene. As shown in FIG. In addition, a pendulum 54 that is rotatable about a shaft 53 in a case 52
With a movable coil 55, a bridge circuit composed of R0, R1, and R2, a pair of left and right photocouplers of a light emitting element LED1, LED2, and light receiving elements PT1 and PT2, and an external power supply E.
Consists of

When the tilt sensor 51 is in the horizontal state, the light receiving amounts of the light receiving elements PT1 and PT2 are equal and the bridge circuits are balanced. When the tilt angle (θ1) is tilted, the pendulum 54 moves in the direction of gravity (vertical direction).
So that one light receiving element PT1 is
Is blocked, and the other light receiving element PT2 receives light and turns on.
When the balance of the bridge circuit is lost and a current flows through the movable coil 55, and when the rotational torque generated in the movable coil 55 and the moment due to the weight of the pendulum 54 are balanced by the current (θ2), the pendulum 54 stops, 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 denotes an A / D converter with an amplification circuit.

Reference numeral 56 denotes a speed sensor provided in the vicinity of the rolling shaft 22 of the seedling plant 10, and detects an angular velocity when the seedling plant 10 rotates left and right around the axis of the rolling shaft 22. In the embodiment, as the speed sensor 56, a thin disk-shaped piezo plastic film is mounted as a vibrator in the case, and the diaphragm structure fixed on the circumference can separate vertical and horizontal components in the acceleration direction. Using an acceleration sensor, the integration circuit of the control means 50 integrates the acceleration, which is the detection value, at appropriate small time intervals.
The angular velocity at each time is obtained.

Reference numeral 57 denotes an A / D converter with an impedance converter connected to the output unit of the acceleration sensor 56.

The control means 50 executes program control of fuzzy inference by a microcomputer including an 8-bit one-chip microprocessor or the like, and executes a central processing unit (various operations and fuzzy inference (described below)) for executing various operations. CPU), read-only memory (ROM) that stores initial values and control programs in advance, read-write memory (RAM) that stores time-varying input signals and the like and outputs them at the time of calculation, and is connected to the input / output unit Interface.

In the first embodiment, the inclination angle θ, which is a detection result of the inclination sensor 51 mounted on the seedling plant 10, and the angular velocity V, which is the detection result of the speed sensor 56, are all input. According to the magnitude of the angle and the magnitude of the angular velocity, the control means 50 outputs a signal of a correction amount S for controlling the right and left inclination of the seedling plant 10 to maintain the posture in a substantially horizontal state. Then, the drive circuit 59 of the electromagnetic solenoid of the control valve 48 for the attitude control hydraulic cylinder 29 is operated.

At this time, since the magnitude and direction of the angular velocity (speed) can be determined by the output of the speed sensor 56, the actuator (hydraulic cylinder) 29 is operated in a direction to cancel the angular velocity (speed) and at a high speed. However, according to the fuzzy inference described later, the most preferable fuzzy rule is created for the operation direction and speed of the actuator 29 from experimental results and the like, and the rule is executed in accordance with the rule.

The control flow will be described with reference to the flowcharts shown in FIGS. 7 and 8. FIG. 7 is a main flow,
In step 701 following the start, initial settings for initializing the fuzzy control relation and the timer are executed, and in step 702, the ON / OFF of an automatic switch for executing posture control automation is determined. The posture is controlled by the lever. The hydraulic cylinder 29 at this time
The moving speed of the piston rod is about 20 milliseconds / second.

If the automatic switch is ON, it is determined in step 704 whether the planting work switch is ON or OFF. If it is OFF, the process returns to step 702.

When the planting operation switch is ON, fuzzy control described later is executed approximately one second later (step 705).

After the execution of fuzzy control, the planting work switch is turned off.
When it becomes F (Step 706), the seedling planting device is approximately 0.5 seconds after the OFF.
The float 10a in 10 is lifted away from the field scene, and the hydraulic cylinder 29 is returned to the center so that its left and right sides are horizontal (step 707). Hydraulic cylinder 2 at this time
The moving speed of the 9 piston rod is about 20 milliseconds / second.

If it is determined in step 706 that the planting work switch is ON, it is determined in step 708 whether the automatic switch is ON or OFF. If it is ON, the process returns to step 705, and if it is OFF, the process returns to step 702.

Following the start of the fuzzy control subroutine flowchart shown in FIG. 8, the detected values of the inclination angle θ and the angular velocity V are read (step 801).

In step 802, the specific values of the detected values θ and V are assigned to 11 divisions by integers from -5 to +5 (area division). For example, when indicating the inclination angle θ, if the negative sign (−) is a downward slope and the positive sign (+) is a downward slope, θ is −
The range from 1 degree to +1 degree is defined as the range of "0", and the values from -16 degrees to +16 degrees are divided into three sections in total, and the total is 11 sections,
[−5, −4, −3, −2, −1, 0, 1, 2, 3, 4, 5] (see FIGS. 10 and 11).

In step 803, the weight of the membership function for the values of the region from -5 to +5 for both θ and V is obtained from the data read from the read-only memory (ROM).

Next, in step 804, it is applied to fuzzy rules based on fuzzy inference.

Further, in step 805, referring to the table of the membership function of the correction amount S for controlling the attitude of the seedling plant, the MAX-MIN
By performing the calculation of the I method, in step 806, the corrected instruction amount S0 is obtained by the center of gravity method, and in step 807, an output signal to the electromagnetic solenoid to the hydraulic cylinder 29 as an actuator is issued in accordance with the instruction amount S0, The amount of protrusion and retraction of the piston rod of the hydraulic cylinder 29 is regulated and controlled so that the left and right posture of the seedling plant 10 is substantially horizontal. Restores horizontally to the left and right.

Next, fuzzy control using fuzzy inference will be described.

In general, a control algorithm is described as an ambiguous relationship between input variables of a plurality of information for control, for example, two input variables (x, y) and an output (operation amount) z to a control device.

 For example, if x is small and y is large, let z be medium.

 If x is large and y is medium, z is increased.

, The control algorithm is (if ‥‥
It is expressed by what is called an (if-then) fuzzy rule.

 The if ‥‥ part of the rule is called the antecedent part (input part), and the then ‥‥ part is called the consequent part (output part).

Now, when this fuzzy rule is applied to attitude control, in this embodiment, it is expressed by 17 rules shown in FIG. At this time, the inclination angle θ and the angular velocity V are defined as the antecedent part, and the correction amount S is defined as the consequent part.

Further, the fuzzy variables taken by the input variables θ, V and the output variable S are indicated by discrete fuzzy variables discretized into an integer area, and are shown in FIGS. 10 to 12.

These fuzzy variables are labeled as "large right", "small right", "0", "small left", and "large left".

The fuzzy variable region, which is an ambiguous region, is defined by giving a degree (grade) in which elements (members) of the total superposition of the input variables are included in the region (variation). The function that gives is called the membership function. For example, the region of the fuzzy variable of θ is defined by giving a degree (grade) in which elements (members) of the entire set of the inclination angle θ are included in the region (variation). In the embodiment, the grade in each domain is represented by an integer from 0 to 10.

More specifically, for example, at the inclination angle θ, the fact that the fuzzy variable is “small right” means that the grade is “3, 5, 8, 10, 10” in the region of “−1 to +5”.
8,5,3 ".

The inference method in fuzzy control is as follows. For example, consider the case of output S (consequent part) for the antecedent part (from to) of a two-input set of θ and V.

First, a membership function A (θi) is obtained from the chart of the membership function corresponding to the value of the antecedent part of each input θ (FIG. 10), and the membership function corresponding to the value of the antecedent part of the input V is obtained. The value of the membership function A (Vi) is determined from the function chart (FIG. 11). It can be seen that there can be a plurality of labels for the region of each input θ, V. Therefore, among the combinations of the labels, the values of the membership functions A (θi) and A (Vi) in the i-th rule (from to) 9 is obtained from FIG. 9, and the fitness ωi = A (θi) * A (Vi) is determined by the combination of the input θi and Vi.

Here, * is a symbol of mini (intersection in a fuzzy set, the same applies hereinafter).

Then, the inference result corresponding to the i-th rule is obtained from FIG. 12, and the fitness wi is obtained from the membership function B (si).
B (si) = ωi * B (si) is obtained.

Next, similarly to the above, the membership function A (θ in the j-th rule corresponding to the value of the antecedent part of the inputs θ and V
j) and A (Vj) are determined from FIGS. 10 and 11, and the fitness ωi = A (θj) * A (Vj) is determined.

Next, the inference result corresponding to the j-th rule is obtained from FIG. 9, and the fitness wiB is obtained from the membership function B (sj).
(Si) = ωi * B (sj) is obtained (see FIG. 12).

When the plurality of consequent parts are, for example, four patterns of i-th, j-th, k-th, and l-th, the overall inference result s0 by these four rules is wiB (si), wjB (sj), wkB (sk),
From wlB (si), B * = wiB (si) UwjB (sj) UwkB (sk) UwlB (sl) is created (U is a symbol of union), and it is obtained as the center of gravity of the membership function of B *. is there.

At this time, it was found that good results could be obtained by using the MAX.MINIMUN method as described later.

If this control is shown in an example of actual numerical values, it is assumed that the inclination angle θ and the angular velocity V are detected, and the area of θ is “0” and the area of V is “−3”.

First, looking at the vertical frame in the area “0” from FIG. 10, the label “5” in “small right”
"10" in "0" and "5" in "small left"
It can be seen that the labels of these three fuzzy variables can be taken.

Regarding the acceleration G, looking at the vertical frame portion corresponding to the section of the area “−3” in FIG. 11, “3” at the label “0”, “8” at “small left”, and “large left”
Therefore, there is a possibility that these three fuzzy variables can be adopted.

Thus, the fuzzy rule based on the data set of θ and V can be found from FIG.
(Note: There is no combination rule where θ is “small right (down)” and V is “large left (down)”).

The labels of the consequent part S corresponding to the above eight rules are “0 (neutral)”, “small right up”, “small left up”, “small left up”, “0”, “small left up” ,
It can be seen that "Large left up" and "Large left up".

Referring to FIGS. 9 to 12, these membership functions are described with reference to FIGS.
13-b and 13-c, the fuzzy rules are shown in FIGS. 14-a, 14-b and 14-c, and the fuzzy rules are shown in FIGS. 15-a and FIG.
It is shown in Figure 15-c. Since other fuzzy rules are obtained in the same manner, illustration is omitted.

In this case, for example, for the fuzzy rule
Comparing the values of ωi of V and V, the value of “0” for θ is “10”, and for V, “−”
The value of the location "3" is "3", and since this "3" is the minimum value, this minimum value is adopted and the fitness ωi of the correction amount S
Is a region surrounded by a thick line which is a portion below the height "3" as shown in FIG. 13-c.

Similarly, the membership function in each consequent part S in the rule of is a region surrounded by a thick line shown in FIGS. 14-c and 15-c.

Similarly, for the other rules,..., The values of ω of θ and V are compared and the smallest side is adopted, and the area of the membership function in each consequent S is determined from these. .

Next, the correction instruction amount S0 of the entire inference result by the eight rules is obtained by calculating the union of the minimum areas of the membership functions in the respective consequent parts S (this is called the MAX.MINIMUN method), Is determined as the center of gravity of the area surrounded by the outermost area when the membership functions are superimposed (this is referred to as the center of gravity method), and the coordinate position in the left-right direction is used as the correction instruction amount (see FIG. 16). At this time, overlapping area portions are not added.

 In this embodiment, the correction instruction amount S0 is approximately 1.07.

In accordance with this numerical value, an output signal is output from the central control device 50 to the drive circuit 60, the electromagnetic solenoid of the control valve 48 is operated, and the hydraulic cylinder 29, which is an actuator for rolling control, is operated. The correction is made so that the horizontal posture is left and right.

Also, as the membership function in each of the fuzzy inferences, a "bell-shaped" or "triangular" well-known in fuzzy theory may be employed instead of the "discrete type (stage type)" described above. .

As described above, when the fuzzy control in which the inclination angle and the inclination speed are set as the antecedent portion (input portion) and the correction amount of the lateral inclination of the working machine such as the seedling plant is set as the consequent portion (output portion), the conventional fuzzy control is performed. Compared to normal numerical control (control using a function of a mathematical expression with the input detection value as a variable) in consideration of the normal tilt angle, acceleration, and possibly tilt speed, accuracy is lacking due to ambiguity, but rapid In addition, it is possible to realize smooth (non-jerky) movement control.

FIG. 18 is a diagram showing the relationship between the actual left-right inclination angle θ ′ of the seedling plant as a working machine and the output V from the speed sensor 56. The direction indicates a state of leftward inclination.

If the traveling machine 1 is provided with a speed sensor and the seedling plant 10 is provided with an inclination sensor, the movement (angular speed) of the seedling plant during posture control will not be picked up by the speed sensor, resulting in malfunction or hunting during control. The phenomenon can be eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention. FIG. 1 is a plan view of a riding type rice transplanter, FIG. 2 is a side view, and FIG. FIG. 4 is a block diagram of a control device and an operation explanatory view including a hydraulic circuit, and FIG. 5 is a V-V of FIG.
FIG. 6 is a block diagram of the tilt sensor, FIG. 7 and FIG. 8 are flowcharts, FIG. 9 is a diagram of the fuzzy rule, FIG. 10 is a diagram showing a membership function of the tilt angle θ, FIG. FIG. 11 is a diagram showing a membership function of angular velocity V,
FIG. 12 is a diagram showing a membership function of the correction amount S, and FIG.
-A, 13-b and 13-c are diagrams of the membership function for the fuzzy rule, and Figs. 14-a, 14-b and 14-c are for the fuzzy rule. 15-a, 15-b, and 15-c are diagrams of membership functions in the case of fuzzy rules, and FIG. 16 is a diagram of membership functions.
Illustration of the MAX.MINIMUM method and area centroid method, Fig. 17 shows the relationship between the actual tilt angle and the output of the tilt sensor and the speed sensor output, and Fig. 18 shows the relationship between the actual tilt angle and the output of the speed sensor. FIG. 1 ... running body, 3,5 ... wheels, 10 ... seedling plant, 15 ...
… Seedling table, 16… Planting mechanism, 11… Link mechanism, 22…
Rolling shaft, 51: Tilt sensor, 56: Speed sensor, 29: Hydraulic cylinder, 48: Control valve, 60: Drive circuit, 50: Control means.

Claims (1)

(57) [Claims] A work machine is mounted on a traveling machine so as to be rotatable left and right and up and down, and an actuator interposed between the traveling machine and the work machine controls the work machine to be kept in a horizontal state. An agricultural work machine configured to execute;
The work machine is provided with an inclination sensor for detecting the left-right inclination angle thereof, and a speed sensor for detecting a speed or an angular velocity at the time of the left-right rotation of the work machine. A horizontal attitude control device in a farm work machine, comprising a control means for obtaining a control output.