JPH0147121B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a sensor for detecting the left and right tilt angle of the machine body on the side of the main machine connected to the ground work device via a three-point linkage mechanism, and The present invention relates to a work vehicle with a rolling control mechanism, which is equipped with a rolling control mechanism that adjusts the ground attitude of the ground work device by extending or contracting one lift rod in the three-point linkage mechanism based on the detection result of the body inclination angle.

[Conventional technology]

In conventional work vehicles with this type of rolling control mechanism, a rolling detection sensor was attached to the ground work equipment side, but when using this,
When attempting to perform rolling control for each task by selectively connecting various ground work devices such as a tilling rotary or multiple plows to the traveling machine,
It is necessary to attach a sensor to each ground work device, making it extremely troublesome to set up and replace the sensors. In addition, when a ground work device to which a sensor cannot be attached is connected to a traveling main machine, there is a drawback that work cannot be performed in a rolling control mode. He first proposed an idea for a side-mounted working machine (Utility Application No. 1983-99000).

[Problem to be solved by the invention]

However, in the rolling control of this work machine, the posture control of the connected work equipment is not sufficient, and there are the following disadvantages.

That is, the rolling control mechanism is configured to adjust the posture (horizontal inclination) of the working device by the torsional movement of the entire three-point linkage mechanism by extending and contracting one of the lift rods, so that the standard posture ( Depending on the direction of inclination of the aircraft with respect to the horizontal state, the amount of expansion and contraction (control amount) of the rod differs even if the inclination angle is the same.

Specifically, as shown in FIG.
Lower links 6, 6' forming a three-point link mechanism
is supported in a suspended state via lift rods 7 and 7', and when one (right side) lift rod 7' is extended or retracted, this three-point linkage mechanism does not have a single rolling axis. , the ground work device (not shown) performs a rolling operation using the lower link 6 of the non-extendable lift rod 7 (left side) as a pseudo center, and the reference posture (horizontal) mentioned above is different from the left and right. lift rod 7,7'
This is the attitude of the ground working device in a state where the respective lengths are set to be equal, and in this attitude, the ground working device is parallel to the traveling main machine.

Here, the difference between the lift rod 7' when the ground work equipment is rolled by an angle of +β by contracting the lift rod 7', and the case where the ground work equipment is rolled by an angle of -β by extending the lift rod 7'. Comparing the amount of expansion and contraction,
Since the left and right lower links 6, 6' are connected to the ground work equipment at their terminal ends, the distance between them does not vary widely and is maintained at a constant distance.
As shown in the figure, a connecting point Q between the extendable lift rod 7' and the lower link 6' moves in an arc around the other lower link 6.

Also, in this way, the ground work equipment can be set at angles +β, -β.
The straight line distance to the lift arm 3' from the connection points +Q and -Q between the lift rod 7' and lower link 6' when rolling the ground work device by angles +β and -β is as follows: These are the dimensions of the lift rod 7'.

Then, assuming a straight line V connecting the connection point Q between the lift rod 7' and lower link 6' on the telescopic side and the lift arm 3' on this side with the ground work device set horizontally, the rolling axis and the above +β,
Assuming that the intersection points of the straight line V connecting -β with the straight line V are +R and -R, the straight-line distances L _u and L _D from the lift arm 3' on this side to the connecting points +β and -β are the radii. Draw a circular arc and assume the intersection points +Q' and -Q' of this circular arc and the straight line V, and calculate the straight line distance L _p between the lift arm 3' on this side and the connection point Q.
Assuming that, the distances between the connection point Q and the intersections +R and -R are equal, and the distance ΔU between the intersections +R and -Q' is greater than the distance ΔD between the intersections -R and -Q'. In other words, since the relationship ΔU > ΔD holds, the relationship L _D −L _p >L _p −L _u holds, and this three-point linkage mechanism retracts the lift rod 7' with the ground work device in the horizontal position. When the area is rolled,
Even if the amount of rolling is the same when the lift rod 7' is rolled in the area where the lift rod 7' is extended, the amount of extension is larger than the amount of contraction of the lift rod 7'.

Incidentally, the shape of the three-point linkage mechanism actually provided in agricultural tractors and the like when viewed from the rear is as shown in FIG. 6' spacing is set large, lift rod 7,
7' will be placed in an inclined position.

If we perform a similar analysis to the one described above for the rolling operation of the ground work equipment using the three-point linkage mechanism configured in this way, we find that L _D −L _p <L _p −L _u , which is the opposite of the above. You can understand that you can acquire characteristics.

In other words, this inconvenience occurs because when performing a rolling operation on a ground work device supported via a three-point linkage mechanism, the rolling operation is performed by the extension and contraction of one lift rod, and this characteristic is also due to the three-point linkage mechanism. It is not constant depending on the form.

For this reason, it has also been found that if proportional control is performed immediately based on the detected inclination angle of the sensor, an inconvenience occurs in that the error increases.

An object of the present invention is to control the rolling of a ground work device with high precision even when the ground work device is controlled to be tilted in any direction with respect to a position parallel to the traveling main machine. be.

[Means to solve the problem]

A feature of the present invention is that, in a working vehicle that performs rolling operation of the ground working device by extending and retracting one lift rod of the three-point linkage mechanism as described above, the ground working device is set based on the detection result of the sensor. It is determined whether the target attitude is located in the region where the lift rod is retracted or the region where it is extended, based on the parallel attitude of the vehicle to the traveling vehicle, and whether the vehicle is located in the region within either region. When a certain amount of inclination occurs, a control gain for the inclination angle of the rolling control mechanism is set based on the determination result so that the amount of rolling operation for restoring the ground work device in response to this inclination is equal to the predetermined amount. The point is that means for switching to different gains is provided, and its operation and effects are as follows.

[Effect]

If the above characteristics are configured as shown in FIGS. 2 and 3, for example, the target attitude of the rolling control of the ground work device 2 is horizontal (parallel to the ground), and the traveling main machine 1 is moved to either the left or right with respect to the horizontal. In the _case of tilting in _{the direction} of θ| is converted into two types of characteristics, and this converted signal becomes the target voltage _Vz .

If a graph is drawn based on the horizontal inclination of the running machine 1 at this target voltage _Vz , it will be as shown in FIG.

〔Effect of the invention〕

Therefore, even if the ground working device is controlled to tilt in any direction with respect to the posture parallel to the traveling main machine, the rolling control of the ground working device can be performed with high precision.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a tilling rotary 2, which is an example of a ground work device, is installed at the rear of a tractor 1, which is a traveling main machine, and a pair of left and right lift arms 3,
A pair of left and right lower links 4 interlocked with 3',
2, the working machine is connected to the tractor 1 through a three-point link mechanism 6 consisting of a top link 5 and a top link 5 so that the tractor 1 can be driven up and down in a rolling state, as shown in FIG. A sensor S1 is attached to the tractor ₁ side for detecting the rolling of the tilling rotary 2 accompanying the rolling of the tiller rotary 2, that is, the horizontal tilt angle θ with respect to the horizontal, and based on the detection by this sensor S1, the corresponding lower link By expanding and contracting one of the pair of left and right lift rods 7, 7' that connects the tilling rotary 2 and the lift arms 3 and 3' via a hydraulic cylinder 8, the left and right posture of the tilling rotary 2 relative to the ground can be changed. A rolling control mechanism A is provided that automatically corrects the posture to a set posture (horizontal posture).

The three-point linkage mechanism 6 is configured so that the tilling rotary 2 can be raised and lowered relative to the tractor 1 by driving its lift arms 3 and 3' up and down using hydraulic cylinders 9. The height of the tillage rotary 2 above the ground is adjustable.

Further, the hydraulic cylinder 8 that extends and retracts one of the lift rods 7' is provided with a sensor _S2 that detects the amount of extension and contraction l.
It is configured to detect the length displacement of.

The sensor S ₁ is a rotary potentiometer that is operated by a hanging weight that can swing left and right, and it outputs a voltage V ₁ corresponding to the rotation angle, that is, the tilt angle θ of the aircraft. It is configured to occur.

On the other hand, the sensor S ₂ is a linear sliding type potentiometer, and is configured to generate a voltage V ₂ corresponding to the amount of expansion/contraction 1 of the hydraulic cylinder 8.

Next, a control circuit for adjusting the left and right tilted posture of the tilling rotary 2 based on the detected voltages V ₁ and V ₂ of the sensors S ₁ and S ₂ will be explained in detail with reference to FIG.

The control circuit 10 basically uses the output voltage V ₁ of the sensor S ₁ as a reference for the aircraft inclination angle θ (horizontal state θ = 0).
A preamplifier A ₁ converts the magnitude and direction of the displacement from θ into a voltage V〓 that can be determined, and the output voltage V〓 of this amplifier A ₁ is controlled by the control gain according to the direction of displacement with respect to the reference of the tilt angle θ. A gain converter 11 for changing the output voltage of this converter 11, V|〓|
and the output voltage V of the amplifier A ₁ to convert it into a target voltage V _z of the cylinder length corresponding to the expansion/contraction amount l of the hydraulic cylinder 8, and the output voltage _{V 2} of the sensor S ₂ a preamplifier A ₃ that converts the voltage V 3 to a voltage Vl corresponding to a cylinder length having the same scale as the scale of the target voltage V _z , the target voltage V _z
a comparator group 13 that generates a control signal for driving the electromagnetic valve 12 of the hydraulic cylinder 8 by comparing the detection voltage Vl of the cylinder length with the detection voltage Vl of the cylinder length, and a driver that receives the output signal of the comparator group 13 and drives the electromagnetic valve 12. The hydraulic cylinder is configured by a circuit 14 so that the target voltage Vz converted based on the body inclination angle _θ of the sensor _S1 is equal to the detected voltage Vl corresponding to the cylinder length of the sensor _S2 . By controlling the amount of expansion and contraction of 8,
The attitude of the tilling rotary 2 is maintained horizontally regardless of the horizontal inclination of the traveling main machine 1.

The preamplifier A ₁ converts the voltage V ₁ output from the sensor S ₁ into a voltage V 〓 proportional to the tilt angle θ with respect to a reference voltage V 〓H corresponding to the state where the aircraft is horizontal θ = 0. It is configured as expected.

That is, when the output voltage V〓 is larger than the reference voltage V〓H, it corresponds to the case where the aircraft ascends to the right θ>0, and when it is smaller, it corresponds to the case where the aircraft ascends to the right and θ<0.

The gain converter 11 has a negative range V〓 with respect to a reference voltage V〓H of the output voltage V〓 of the preamplifier _A1 .
<V〓H voltage is inverted and amplified with a predetermined gain _K1 , and the output voltage is OV in the positive range V〓≧V〓H, and the reference voltage _V〓H of the voltage V〓. , the voltage in the positive range V〓>V〓H is set to the predetermined gain.
Non-inverting amplification is performed with K ₂ , and in the negative range V〓≦V〓H, the output voltage is OV.The output voltage of the non-inverting amplifier _A5 , this amplifier _A5 , and the amplifier _A4 is V|+θ
|, V|-θ|, and determines the magnitude of the detected voltage V〓 with respect to the reference voltage V〓H, that is _, the direction of the inclination angle θ,
A comparator _A7 is provided which outputs a logic signal _C1 of "H" level when the upper left corner is θ<0, and a logic signal C1 of the "L" level when the upper left corner θ<0, thereby forming a circuit equivalent to an absolute value circuit.

The operational amplifier _A2 is configured to add or subtract the voltage V corresponding to the tilt angle θ and the output voltage V|〓| of the absolute value circuit, which is the gain converter 11, depending on the direction of the tilt angle θ. , an analog switch _SW1 for switching the addition polarity by a comparator _A7 is provided, and a voltage _Vz having the characteristics shown in FIG. 4 is generated.

The comparator group 13 has the following configuration 4
Three comparators A ₈ , A ₉ , A ₁₀ , A ₁₁ are provided, and a control signal C ₂ for extending the hydraulic cylinder 8,
It is configured to output a control signal C ₃ for reducing the frequency and a control signal C ₄ for switching the oscillation frequency of the oscillator 15 of the driver circuit 14 .

That is, the comparators A ₈ and A ₉ have the voltages V _z ,
Reference voltage with the difference between V _l set as dead band width
In comparison with V〓 ₂ and V〓 ₁ , control signals C ₂ and C ₂ are outputted, respectively.

The comparators A ₁₀ and A ₁₁ are connected to the voltages V _z ,
The difference in V _l is compared with reference voltages VD ₁ , VD ₂ set outside the reference voltages V〓 ₂ , V〓 ₁ with OV at the center, and the range of these reference voltages VD ₁ , VD ₂ is found to be VD ₁ < |V _z −V _l |
In order to output the “H” level control signal C ₄ when there is a voltage difference |V _z −V _l | in <VD ₂ , the AND
A logical product (AND) process is performed by gate _G1 .

The driver circuit 14 of the electromagnetic valve 12 includes:
An oscillator 15 provided to drive the electromagnetic valve 12 intermittently, and an output of the oscillator 15 is opened and closed.
AND gates G ₂ , G ₃ and this gate G ₂ , G ₃
The electromagnetic valve 12 is activated by the oscillator 15 via the oscillator 15.
Solenoid drive circuits A ₁₂ and A ₁₃ are provided to drive the solenoid intermittently.

The gates G ₂ and G ₃ are the comparators A ₈ and A ₉
The output of the oscillator 15 is input to one of the drive circuits A ₁₂ and A ₁₃ by control signals C ₂ and C ₃ outputted from the oscillator 15.

On the other hand, the oscillator 15 is configured to be able to switch its oscillation frequency, and the comparators A ₁₀ ,
The oscillation frequency is configured to be switched by the control signal _C4 outputted via the AND gate _G1 of _A11 .

This switching of the oscillation frequency is performed at the aircraft inclination angle θ
When adjusting the posture of the tilling rotary 2 by expanding and contracting the hydraulic cylinder 8 according to the angle of inclination θ, the expansion and contraction speed of the hydraulic cylinder is slowed to prevent the posture from changing suddenly It is set up for this purpose.

In addition, SW ₂ is a switch for parallel control to forcibly make the attitude of the tilling rotary 2 parallel to the tractor 1, and the control valve (not shown) of the hydraulic cylinder 9 for lifting the lift arm is switched to the ascending position. When this happens, the reference voltage _VH is switched to be input to the comparator group 13 instead of the target voltage Vz of the operational amplifier _A2 . Therefore,
When the machine makes a U-turn on a headland or when the tilling rotary 2 is raised for non-working travel, the tilling rotary 2 is automatically corrected to a reference posture parallel to the tractor 1. Further, SW ₃ is an automatic/manual changeover switch provided to manually vary the attitude (horizontal inclination) of the tilling rotary 2 with respect to the tractor 1, and P is a potentiometer as a means for setting the inclination angle.

[Brief explanation of drawings]

The drawings show an embodiment of a working vehicle with a rolling control mechanism according to the present invention, in which FIG. 1 is an overall side view, FIG. 2 is a perspective view of main parts, and FIG. 3 is a block diagram of the control mechanism.
Figure 4 is a control gain characteristic diagram, Figure 5 A is a principle diagram showing the rolling operation with equal spacing between the lift arm and lower link, and Figure 5 B is a three-point link actually used. It is a principle diagram showing rolling operation by the mechanism. 1... Traveling main machine, 2... Ground work device, 6...
Three-point linkage mechanism, 7'... Lift rod, A...
Rolling control mechanism, S ₁ ...Aircraft tilt detection sensor, θ...Inclination angle.

Claims (1)

[Claims] 1 A sensor S ₁ for detecting the horizontal tilt angle θ of the machine body is installed on the side of the running machine 1 connected to the ground work device 2 via the three-point linkage mechanism 6, and based on the detection result of the machine body tilt angle θ of this sensor S ₁ . , the three-point linkage mechanism 6
The working vehicle is equipped with a rolling control mechanism A that adjusts the ground attitude of the ground working device 2 by expanding and contracting one of the lift rods 7', and is set based on the detection result of the sensor _S1 . The target attitude of the ground work device 2 is based on the parallel attitude of the main machine, and the lift rod 7'
In addition to determining which side of the contraction area or expansion area it is located, if the traveling main machine 1 is tilted by a predetermined amount in either area, the ground work device is adjusted in response to this inclination. The rolling control mechanism is provided with a means for switching the control gain of the rolling control mechanism A for the inclination angle θ to a different gain based on the determination result so that the amount of rolling operation for restoring the angle θ is equal to the predetermined amount. work vehicle.