JPH0147961B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention comprises a pair of lower links that are suspended from a pair of lift arms via lift rods, and a single top link. A sensor for detecting the left and right tilt angle of the machine is provided on the side of the traveling machine that constitutes a three-point linkage mechanism and is connected to the ground work device via this three-point linkage mechanism, and based on the detection result of the machine body lean angle by this sensor, The present invention relates to a working vehicle with a rolling control mechanism, which includes a rolling control mechanism that adjusts the ground posture of the ground working device by extending and contracting one lift rod in the three-point linkage mechanism.

[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 running 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. If the reference posture of the three-point linkage mechanism itself is changed in order to change the working height above the ground, there is an inconvenience that an error occurs in the desired posture (for example, horizontal).

To explain specifically, the link system on the side of the lift rod that operates to expand and contract is shown in Figure 5, and in this figure, the link system on the side of the lift rod that operates to expand and contract is shown in Figure 5.
The lower link 6' is supported in a suspended state via the lift rod 7', and when the ground work equipment (not shown) is to be operated in a rolling manner, only the lower link 6' on this side is moved by the expansion and contraction of the lift rod 7'. When adjusting the level of the ground work device, the pair of lift arms are pivoted together.

Here, lift arm 3', lift rod 7',
With each lower link 6' set in the posture shown by the solid line, if the lift rod 7' is extended or contracted by a unit amount l, the swing amount of the lower link 6' is determined by the angle Become.

Next, the lift arm 3' is swung in the downward direction by an angle Y, and with the lift arm 3', the lift rod 7', and the lower link 6' set in the postures shown by the broken lines, the lift rod 7' is moved in the same manner as described above. If the form in which the lower link 6' is expanded and contracted by a unit amount l is determined by drawing, the amount of swing of the lower link 6' is an angle X'.

If you compare the angles X and X', it is clear that the angle The amount of swing of the lower link 6' varies depending on the lift angle of the lower link 6'. In other words, a difference occurs in the amount of rolling operation.

In addition, in the three-point linkage mechanism configured in this way, as shown in FIG. The amount of swing of the lower link 6' is determined, and in this configuration, the connection angle is
The closer the angle is to the right angle, the more the lower link 6' swings.
become smaller.

An object of the present invention is to enable attitude control of a ground working device to be performed as accurately as possible, no matter what type of ground working device is used at any level.

[Means to solve the problem]

A feature of the present invention is that in a working vehicle configured to perform rolling operation of a ground working device supported via a three-point linkage mechanism as described above by the extension and contraction of the lift rod, the ground working device is operated by driving the lift arm. When adjusting the level of the ground work device, the angle of inclination detected by the sensor is adjusted so that the amount of swing of the lower link with respect to the unit extension/contraction operation of the lift rod is maintained at a predetermined value regardless of the level of the ground work device. The control target signal set based on the control target signal is corrected based on the detection result of the sensor that detects the lift angle of the three-point linkage mechanism, and its operation and effect are as follows. It is.

[Effect]

When the above characteristics are configured as shown in FIGS. 2 and 3, for example, the gain converter 11 outputs a voltage signal (V|θ|), which is the source of the control target signal, based on the left and right inclination of the traveling aircraft. This voltage signal (V|θ|) is applied to the sensor corresponding to the lift angle α.
As a result of being divided by S ₂ , it is converted into a voltage signal V ₂ ,
Thereafter, it is converted into a target voltage _Vz via amplifiers _A2 and _A3 .

In other words, in this configuration, when the lift angle α is constant, a predetermined control target is set in response to the left and right inclination of the traveling body, and this control target is generated in response to the lift angle α of the three-point linkage mechanism. It is converted (corrected) into a value that cancels out the control error.

Incidentally, in the configuration shown in FIG. 3, the sensor _S2 is also used as the "correction means" described in the claims.

〔Effect of the invention〕

Therefore, no matter what type of ground work equipment is used at any level, it has become possible to control the attitude of the ground work equipment 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 with respect to the tractor 1 by driving its lift arms 3 and 3' up and down by a hydraulic cylinder 9, A sensor _S2 for detecting the lift angle α of the lift arms 3, 3' with respect to the tractor 1 is provided at the lift arm fulcrum.

On the other hand, the hydraulic cylinder 8 that extends and contracts the lift rod 7' has a sensor that detects the amount of extension and contraction.
_S3 is provided and is arranged to detect the length displacement of the lift rod 7'.

The sensors S ₁ and S ₂ are rotary potentiometers, and are configured to generate voltages V ₁ and V ₂ corresponding to the rotation angles θ and α, respectively. In particular, the sensor S ₁ is A device that is rotated by a hanging weight that can swing left and right is used.

On the other hand, the sensor S ₃ is a linear sliding type potentiometer, and is configured to generate a voltage V ₃ corresponding to the amount of expansion/contraction 1 of the hydraulic cylinder 8.

Next, the detection voltages V ₁ of the sensors S ₁ , S ₂ , S ₃ ,
A control circuit for adjusting the left and right tilted posture of the tilling rotary 2 based on V ₂ and V ₃ will be explained in detail with reference to FIG. 3.

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=O).
A preamplifier A ₁ converts the magnitude and direction of the displacement amount from θ into a voltage Vθ that can be determined, and the control gain of the output voltage Vθ of this amplifier A ₁ is changed depending on the direction of displacement with respect to the reference of the tilt angle θ. gain converter 11 for the output voltage V101 of this converter 11
is input to the lift angle detection sensor S ₂ to generate a divided voltage corresponding to the lift angle α as the output voltage V ₂ of this sensor S ₂ , and a preamplifier that amplifies this voltage with a predetermined gain. A ₂ , this amplifier A ₂
an operational amplifier A 3 that adds or subtracts a voltage Vα corresponding to the lift angle α output from the amplifier A ₁ and an output voltage Vθ of the amplifier A ₁ to convert it into a target voltage V _z for the cylinder length corresponding to the expansion/contraction amount l of the hydraulic cylinder 8; , the output voltage V ₃ of the sensor S ₃ is set to a voltage Vl corresponding to a cylinder length of the same scale as the scale of the target voltage V _z .
a preamplifier A ₄ that converts the target voltage V _z to the detected voltage Vl, a comparator group 13 that generates a control signal for driving the electromagnetic valve 12 of the hydraulic cylinder 8 by comparing the target voltage V z and the detected voltage Vl, and this comparator group 1
The driver circuit 14 receives the output signal of the sensor S3 and drives the electromagnetic valve 12, and the target voltage _Vz converted based on the aircraft inclination angle θ of the sensor _S1 and the cylinder length of the sensor _S3 Hydraulic cylinder 8 so that the corresponding detection voltage Vl is equal to
By controlling the amount of expansion and contraction, the attitude of the tilling rotary 2 is maintained horizontally regardless of the horizontal inclination and lift angle of the tractor 1.

The preamplifier _A1 converts the voltage _V1 output from the sensor _S1 into a voltage Vθ proportional to the tilt angle θ with respect to a reference voltage VθH corresponding to the state where the aircraft is horizontal (θ=O). It is structured as follows.

That is, when the output voltage Vθ is larger than the reference voltage VθH, the aircraft corresponds to an upward movement to the right (θ>O), and when it is smaller, the aircraft corresponds to an upward movement to the left (θ<O).

The gain converter 11 inverts and amplifies the voltage in the negative range (Vθ<VθH) with a predetermined gain _K1 with respect to the reference voltage VθH of the output voltage Vθ of the preamplifier _A1 , and also inverts and amplifies the voltage in the positive range ( Vθ≧VθH), an inverting amplifier A ₅ whose output voltage is OV, non-inverting amplification of a voltage in the positive range (Vθ>VθH) with a predetermined gain K ₂ with respect to the reference voltage VθH of the voltage Vθ, and , non-inverting amplifier A ₃ whose output voltage is OV in the negative range (Vθ≦VθH), and the output voltages (V ₁₊₀₁ ), (V _1-01 ) of this amplifier A ₆ and the amplifier A ₅ are combined. adder A ₇ and a reference voltage of the detection voltage Vθ
Comparator A that determines the magnitude relative to VθH, that is, the direction of the inclination angle θ, and outputs a logic signal C ₁ that is “H” level when rising to the right (θ≧O) and “L” level when rising to the left (θ<O). It is equipped with ₈ ,
A circuit equivalent to an absolute value circuit is constructed.

The operational amplifier A ₂ generates a voltage V θ corresponding to the tilt angle θ and a voltage obtained by correcting the output voltage V ₁ 〓 ₁ of the absolute value circuit, which is the gain converter 11, according to the lift angle α by the sensor S ₂ . A comparator is used to add or subtract Vα from the tilt angle θ depending on the direction.
An analog switch _SW1 is provided to switch the addition polarity according to _A8 , and as shown in FIG. 4, it generates an expansion/contraction target voltage _Vz for the cylinder 8 that is corrected according to the lift angle α.

The comparator group 13 has the following configuration 4
Three comparators A ₉ , A ₁₀ , A ₁₁ , A ₁₂ 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 ₉ and A ₁₀ are connected to the voltages V _z ,
Reference voltage with the difference between Vl set as dead band width
They compare Vθ ₂ and Vθ ₁ and output control signals C ₂ and C ₃ , respectively.

The comparators A ₁₁ and A ₁₂ are connected to the voltages V _z ,
The difference between Vl is compared with reference voltages VD ₁ and VD ₂ set outside the reference voltages Vθ ₂ and Vθ ₁ with OV at the center, and the range of these reference voltages VD ₁ and VD ₂ (VD ₁ < IV _z − VlI
In order to output the “H” level control signal C ₄ when there is the voltage difference (IV _z −VlI) in <VD ₂ ),
Logical AND processing is performed using AND gate _G1 .

The driver circuit 14 of the electromagnetic valve 12 includes:
An oscillator 15 provided to drive the electromagnetic valve 12 intermittently; the output of this 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 ₁₃ and A ₁₄ are provided to intermittently drive the .

The gates G ₂ and G ₃ are connected to the comparators A ₉ and
The output of the oscillator 15 is input to one of the drive circuits A ₁₃ and A ₁₄ by control signals C ₂ and C ₃ output from A ₁₀ .

On the other hand, the oscillator 15 is configured to be able to switch its oscillation frequency, and the comparators A ₁₁ ,
The oscillation frequency is configured to be switched by the control signal _C4 outputted via the AND gate _G1 of _A12 .

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 the reference voltage VθH is input to the comparator group 13 instead of the target voltage _Vz from the operational amplifier _A3 . Therefore, when the machine makes a U-turn on a headland or when the tiller rotary 2 is raised for non-working travel, the tiller rotary 2 is automatically corrected to the 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.
FIG. 4 is a characteristic diagram of the control gain, and FIG. 5 is a principle diagram showing the swinging of the lower link with respect to expansion and contraction of the lift rod. 1... Traveling main machine, 2... Ground work device, 3,
3'...Lift arm, 5...Top link, 6,
6'...Three-point linkage mechanism, 7,7'...Lift rod, A...Rolling control mechanism, S1...Aircraft tilt detection sensor, _{S2 ...} Lift angle detection sensor, θ
...Inclination angle, α...Lift angle.

Claims (1)

[Claims] 1 A three-point link mechanism with a pair of lower links 6, 6' supported in a suspended state via lift rods 7, 7', respectively, and a single top link 5 with respect to a pair of lift arms 3, 3'. A sensor S ₁ for detecting the horizontal tilt angle θ of the machine body is provided on the side of the traveling main machine 1 connected to the ground work device ₂ via the three-point linkage mechanism 6. A working vehicle with a rolling control mechanism, which is equipped with a rolling control mechanism A that adjusts the ground attitude of the ground work device 2 by expanding and contracting one lift rod 7' of the three-point linkage mechanism 6 based on the detection result, When the level of the ground work device 2 is adjusted by driving the lift arms 3, 3', the swing of the lower link 6' with respect to the unit extension/contraction operation of the lift rod 7' is controlled regardless of the level of the ground work device 2. A control target signal set based on the tilt angle θ detected by the sensor S ₁ is transmitted to a sensor S ₂ that detects the lift angle α of the three-point linkage mechanism 6 so as to maintain the amount of movement at a predetermined value. A working vehicle with a rolling control mechanism, comprising means for correcting based on the detection result of.