JPH0457281B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to work vehicles such as harvesters, and specifically proposes an automatic steering device that improves the stability of steering control by automatically correcting the ability to correct left and right direction or irregularities in turning force. be. EMBODIMENT OF THE INVENTION Below, the present invention will be specifically explained based on drawings showing embodiments of a harvester. FIG. 1 schematically shows the divider part at the front of the harvester equipped with the automatic steering device according to the present invention, and the left and right dividers 1l and 1r are shown in FIG.
Steering sensors 20l and 20r are attached to each of them with sensor arms 21l and 21r facing inward of the aircraft body. The steering sensors 20l, 20r are comprised of the sensor arms 21l, 21r and sensor boxes 22l, 22r, respectively. sensor arm 21l
(or 21r) is the grain culm 30l between the divider 1l (or 1r) and the inner divider 1l' (or 1r')
(or 30r), and when the aircraft moves forward, it is pressed by this grain culm ray 30l (or 30r) and rotates backward, and if there is no grain culm ray 30l (or 30r), the sensor box 22l (or 22r) ) It is designed to rotate forward by the action of the spring inside. On the other hand, the sensor box 22l (or 22r) houses three (or two) switches that are operated depending on the rotational position of the sensor arm 21l (or 21r). By logically determining the combination, the energization of the solenoid VSl or VSR of the electromagnetic directional control valve V, which will be described later, is controlled. Figure 2 is a hydraulic circuit diagram of the automatic steering system,
3 is a pump, V is a 4-port 3-position switching type electromagnetic directional control valve, 4l and 4r are respective piston rods 4
Side clutch 5l, 5r due to protrusion of la, 4ra
This is a hydraulic cylinder that can be turned off. Therefore, this hydraulic circuit is connected to the solenoid VSl (or
VSr) is energized, the electromagnetic directional control valve V is switched in the direction of the arrow l (or r), supplies pressure oil to the hydraulic cylinder 4l (or 4r), and operates the left side clutch 5l (or 4r). Alternatively, the right side clutch 5r) is shut off to stop driving the left crawler 50l (or the right crawler 50r), so that the movement of the aircraft can be corrected to the left (or right). Note that when the side clutch 5l is cut off by switching the electromagnetic directional control valve V, the left brake is also applied, and the side clutch 5r
When the brake is cut off, the right brake may also be applied to improve the responsiveness of steering. In this way, the aircraft is configured to turn to the left or right by cutting off the transmission of either the left or right traveling system or decelerating or stopping it by braking, but the solenoid is intermittently energized. The vehicle is configured to intermittently decelerate or stop for turning. Engagement and disconnection of the side clutches 5l and 5r can also be performed by the left and right side clutch levers 6l and 6r provided on the operating column of the harvester, but it is possible to engage and disconnect the side clutches 5l and 5r, respectively. tow the side clutches 5l and 5r.
A limit switch 60 equipped with a normally open contact 60a (see Fig. 3) that closes when either of It is designed so that it can be Next, the electric circuit of the device of the present invention will be explained based on FIG. In FIG. 3, 40 is a microcomputer that is the control center of this automatic steering system, and includes a CPU (central processing unit) 31, a ROM (read-only memory) 32 that stores control programs, and a RAM that temporarily stores various data. (Random access memory) 33, input/output interface 34, etc. 221, 222, 223 are switches forming the left steering sensor 20l; 224, 225;
are switches constituting the right steering sensor 20r, and their respective open/close states are input to the CPU 31 via the input/output interface 34. 61 is a switch that closes when the threshing clutch lever 62 is operated to the threshing clutch input side, and is connected to the input/output port like the normally open contact of the limit switch 60, and the CPU 31 closes the circuit when the former is opened and the latter is closed. No automatic steering control, that is, side clutch levers 6l, 6r
It is designed so that only manual steering can be performed by operating the . Three-point switch 6 installed on the operation column
3 is for selecting "off" which does not perform automatic steering, "intermediate cutting mode" which performs automatic steering during intermediate cutting work, or "row mowing/horizontal mowing mode" which performs row mowing or horizontal mowing. When the switching side terminals 631 and 632 are connected to a common terminal and the latter two are selected, a lamp 64 indicating automatic steering selection is turned on. These control system circuits are supplied with power from a battery 66 via a key switch 65, and the controlled systems, that is, solenoids VSl and VSR, are also supplied with power in the same manner. and these solenoids
VSl and VSR have switch circuits 67 that are controlled on and off by the output of the microcomputer 40.
1 and 67r are interposed in series between the positive and negative electrodes of the battery 66, respectively. Now, the microcomputer 40 is the switch 22.
The switch circuits 67l and 67r are turned on and off, in other words, the solenoids VSl and VSr are energized and de-energized according to the combination of on and off of the switches 1 to 225. The relationship between the on/off states of the three switches 221 to 223 in the left sensor box 22l and the rotational position of the sensor arm 21l is as follows. That is, the sensor arm 21l is connected to the grain culm 30.
If the rotational position of the sensor arm 21l is classified into areas 1, 2, 3, and 4 from the divider 1l side to the 1m side as shown in FIG. The second switch 222 is turned off in areas 1 and 2 and turned on in areas 3 and 4, and the third switch 223 is turned off only in area 4 and turned on in the others. There is. On the other hand, the relationship between the on/off states of the two switches 224 and 225 in the right sensor box 22r and the rotational position of the sensor arm 21r is that the rotational position of the sensor arm 21r is similarly set 1 m from the divider 1r side. When classified into areas a, b, and c, the fourth switch 224 is turned off in areas a and b, and on in area c, and the fifth switch 225 is turned on in areas a and off in areas b and c. There is. The microcomputer 40 that has read this on/off operation operates the solenoid as shown in Table 1.
The program is configured to control energization of VSl and VSR. Table 1 shows the rotation range of the left and right sensor arms 21l and 21r, the on (○) and off (x) of the related switches 221 to 225, and the on (○) and off of energization to the solenoids VSl and VSr. (×) and the progress status of the aircraft are shown in a list. 1 indicates that the on/off status of the switch is undefined or unrelated to control. In addition, under normal conditions, row cutting work is performed from the 6th to
The horizontal mowing work is performed in the manner shown in the eighth column, and the horizontal mowing work is performed in the manner shown in the fourth to sixth columns. As mentioned above, the excitation of the solenoids VSl and VSR is performed intermittently, so the ○ marks in the VSl and VSR columns in Table 1 indicate intermittent energization. As a result of such control, the aircraft travels along the grain culms 30l and 30r.

[Table] Next, the features of the automatic steering system of the present invention will be explained. It is unique in that it is configured to automatically adjust the turning force through learning control. As mentioned above, this automatic steering is performed by controlling the operations of the hydraulic system, side clutches 5l, 5r, etc., but naturally there are manufacturing or structural issues with these mechanical parts. There are differences between the left and right systems, so the solenoid
When energizing VSl and VSr in the same way, the difference in responsiveness of left and right turns due to the above differences,
There will be a difference in the amount of turning. In addition, in the case of a harvester, the rice tank is located on either the left or right side of the machine, so as harvesting progresses, the center of gravity of the machine changes, and the difference in turning force to the left and right increases. The device of the present invention is designed to automatically deal with such problems by changing the duty ratio of the pulse signal that the microcomputer 40 outputs to the switch circuits 67l and 67r for intermittent conduction control. This is achieved by doing. This control will be explained below based on the flowchart of FIG. 4 showing the control contents of the microcomputer 40. First, when the switch 63 is operated to perform automatic steering in the intermediate cutting mode or the row/horizontal cutting mode (that is, when the terminal 631 or 632 is selected),
Set the duty ratio of the pulse signal to be applied to the solenoids VSl and VSR to the initial value. Hereinafter, the duty ratio will be represented by the time width of the elementary pulse of this pulse signal. The pulse width of this initial value is the intermediate value of the settable maximum width P _nax and minimum width P _nio (P _nax + P _nio )/2
It also resets the counter and timer in the CPU 31, which will be described later. Next, flags L ₁ and R ₁ for storing whether the previous direction correction was to the left or right are reset. Then switch 22
Input/output interface 34 in which 1 to 225 are connected
The level of the port is checked to determine whether it is necessary to output right and left turning signals, that is, whether it is necessary to output pulse signals to the switch circuits 67l and 67r (step).
If only the switches 223 and 224 are on as shown in column 7 of Table 1, it is not necessary to output turning signals to the left or right, and this process is repeated.
As shown in Table 8 column (or 6th column), switch 223,
When 224 and 222 (or 221) are turned on, a turning signal to the right (or left) is output, which causes the switch circuit 67r (or 67
l) is turned on intermittently to correct the direction to the right (or left). The turning force at this time is (P _nax +
Of course, the value is determined by P _nio )/2. Now, in the CPU, a flag R ₁ (or L ₁ ) is set in response to the output of a turning signal to the right (or left). The following will explain the case where a right turn signal is output and flag _R1 is set. As flag _R1 is set, counter _R2 starts counting the number of elementary pulses of the turning signal, and timers _R3 and _R4 start timing. This timer R ₃
The timed value t _1R of is compared with a preset time T ₁ ,
Until this time is reached, the counted content n _R of counter R ₂ is compared with a preset number N, and n _R ≧
If N, the pulse width is increased by ΔP unless the pulse width P _tr of the right turn signal at that time is not P _nax . This is done by increasing the pulse width to resolve the situation where a sufficient turn is not made even though a number of pulses equal to or more than the set number N are emitted within the set time _T1 . It means making adjustments to increase strength. If the flag _L1 is not set, the process moves to a step of checking whether the right turn signal is on or off. Although the turning signal is in the form of a pulse, wait until the elementary pulse at this step turns off, check whether the switch 63 is on or off, and return to the step. On the other hand, if n _R < N, it is not necessary to lengthen the pulse width, and if R _tr = P _nax , it is impossible to lengthen the pulse width further, so the pulse width is lengthened by ΔP. Return to the same steps as when the When t _1R =T ₁ , the counter R ₂ and timer R ₃ are reset and the process returns to the same step as before. In short, if N or more pulses are emitted during _T1 time, control is performed to increase the pulse width as it is assumed that the turning force is insufficient. Therefore, if flag _L1 is set,
When this flag is set, that is, when the left turn signal is output before the right turn signal, the flag _L1 is set and the timer _L4 (see step) starts counting the time value t. Compare _2R with the preset time T ₂ . If t _2R ≦T ₂ , the pulse width is decreased by ΔP' unless P _tl is P _nio , the flag L ₁ is reset, and the process returns to the same step as before. This is to eliminate the situation where a turn signal to the right is output in a short time that is less than the set time T ₂ after turning to the left first.
This means making adjustments to weaken the turning force to the left. Therefore, if t _2R >T ₂ , the flag L ₁ and timer L ₄ are reset and the process returns to the step. On the other hand, when a left turn signal is output and flag _L1 is set, processing is performed symmetrically with the above-mentioned process. That is, while the time value _t1L of the timer _L3 , which starts counting when the flag _L1 is set, is less than or equal to _T1 ,
Similarly, when the counter _L2 starts counting the number of pulses of the left turn signal when the flag _L1 is set, if the count value _nL is greater than or equal to N, the pulse width P _tl of the left turn signal at that point is calculated. Increase by ΔP. and if flag R ₁ is set, flag R ₁
The time value t 2L of timer R ₄ , which starts timing when t _2L is set, is compared with T ₂ , and if t _2L ≦T ₂ , the pulse width of the rightward turning signal is shortened by ΔP′. . Note that it is of course possible to set ΔP=ΔP'. With this configuration, the weight inside the paddy tank placed on the right side of the machine increases as the harvesting process progresses, making it easier to turn the machine to the right.
If a situation arises that makes it difficult to turn left, the conditions t _1L ≦T ₁ , n _L ≧N or t _2R ≦T ₂ are satisfied, and the left turn signal is By increasing the pulse width or shortening the pulse width of the rightward turning signal, the left and right turning forces are substantially balanced. This also works to automatically correct any unbalance that exists in the mechanical components that cause left and right steering. Therefore, problems such as insufficient turning force in one direction resulting in misalignment, or excessive turning force resulting in hunting and poor riding comfort are completely eliminated. Furthermore, in the case of the device of the present invention, for example, in a field where grain culms are often curved to the left, the frequency of direction correction to the left increases, and the pulse width of the leftward turning signal becomes longer. The ability to follow the provisions will automatically be improved. As described above, the automatic steering device according to the present invention includes a steering device that intermittently makes direction corrections to the left and right, and a device that calculates the number of times the steering device is driven in one direction within a predetermined period of time. , means for increasing the time for one drive in the one direction if the determined number of drives is greater than a predetermined value, means for storing the previous corrected direction, and means for counting the time since the time of memorization. and means for reducing one driving time in the previous correction direction when the current correction direction and the previous correction direction are different and the time measurement result of the means is less than or equal to a predetermined value. Therefore, the direction correction is made more strongly in the case where the direction correction is difficult to be made, and the direction correction is made weaker in the case where the direction correction is excessive. As a result, the left and right turning force or direction correction ability can be automatically and quickly balanced according to the characteristics of the aircraft and the work situation.
Or, since it automatically and quickly unbalances the vehicle in the direction of increasing followability, ideal steering control can be performed without having to worry about adjusting or setting the turning force. The present invention has extremely excellent effects such as no culm damage.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic plan view of the divider portion, Fig. 2 is a hydraulic circuit diagram of the device of the present invention, and Fig. 3 is a schematic illustration of the main parts of the electric circuit. FIG. 4 is a flowchart of microcomputer control. 20l, 20r...Reaping sensor, 40...Microcomputer, VSl, VSr...Solenoid.

Claims (1)

[Scope of Claims] 1. Steering means for intermittently making direction corrections to the left and right, means for determining the number of times the steering means is driven in one direction within a predetermined time, and the determined number of times the steering means is driven in one direction. is larger than a predetermined value, a means for increasing the driving time in one direction, a means for storing the previous direction of correction, a means for measuring the time since the time of memorization, and a means for measuring the time for the current direction of correction. The invention is characterized by comprising means for reducing one drive time in the previous correction direction when the time measurement result of the means is less than a predetermined value when the direction of correction is different from the previous correction direction. Automatic steering device.