JPH01178622A - Controlling method of bucket angle - Google Patents

Abstract

PURPOSE:To make it possible to control a boom against a bucket holding angle by adding such a control signal as upturning the bucket upper than an actual variation to a bucket angle compensating signal in accordance with the angular velocity of the boom which is moving up and down. CONSTITUTION:When a bucket control lever (c) is turned in neutral, a switch (i) is turned ON by a signal from a sensor (d), and a bucket angle theta0 is stored in a memory (h) as a target holding angle thetaOM of the bucket. When a boom 1 moves, the bucket angle theta0 varies against the target holding thetaOM, and a bucket angle variation signal theta0 is operated by a second operator (j). Simultaneously, a boom angle theta2 is differentiated by a differentiator 21 to operate a dot of the boom angular velocity theta2, and a bucket angle compensating signal K2.1theta2 dot 1 is operated by a third operator 22 to add to the variation signal theta0 by a fourth operator 23. The movement of the boom is such that a position to be upturned only by a factor of the compensating signal K2.1theta2 dot 1 is bucket angle compensating target.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to industrial vehicles such as shovel loaders, and in particular to a brush that has a nozzle connected to a boom that moves up and down so as to be tiltable forward and backward.・It is suitable for use in the method of keeping the no. 1 - no. z and no. of the links constant.

(Prior art) In industrial vehicles such as shovel loaders that have a bucket link that connects a bucket to a boom that moves up and down so that it can tilt forward and backward, the posture of the bucket relative to the ground changes when the boom is rotated up and down. Conventionally, the brush and gutter angles are corrected to a certain extent by a link mechanism consisting of a boom and a brush slotting link, but the link mechanism alone cannot keep the brush and gutter angles completely constant. It was difficult to keep it.

In order to solve this problem, an example of a conventional control method in which the boom angle and the blade/groove angle are electrically detected so that the absolute angle of the blade/throat angle is constant will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram of a detection portion in a bucket angle control method for a shovel loader working machine, and is common to both the present invention and the prior art. In the figure, boom 1 is rotated up and down by boom cylinder 3, bucket 2 is tilted forward and backward by bucket cylinder 4, and when boom 1 is rotated to position 1', bucket 2 is rotated to position 2'.
It shall come to the position of . 6 is a boom angle sensor that detects the angle when the boom 1 rotates and outputs a boom angle signal θ2; 7 is a boom angle sensor that detects the angle when the boom 1 rotates;
The bucket angle when it rotates is the relative angle between the bucket 2 and the boom l, or the stroke of the bucket cylinder 4,
Or detect by the relative angle between link 5 and boom 1,
This is a brush angle sensor that outputs a bucket angle signal θ.

FIG. 5 is an explanatory diagram of the operation of the conventional bucket angle control method, in which a is a manually operated valve installed between the bucket cylinder 4 (see FIG. 1) and the hydraulic pump b, and the bucket operating lever C is A bucket neutral sensor d for detecting the neutral position of the bucket operating lever C is provided. Denoted at e is a solenoid valve for correcting the bucket angle, which allows the pressure oil from the auxiliary pump f to flow into the bucket cylinder 4. g is the bucket absolute angle θ based on the relative angle signal θ1 and boom angle signal θ2 between the bucket 2 (see FIG. 1) and the boom 1 (see FIG. 1). The first calculator h calculates the absolute bucket angle θ when the switch i is turned on by the signal from the bucket neutral sensor d when the bucket operating lever C is in the neutral position. is the target holding angle θ of the bucket. , j is the target holding angle θ of the bucket 2 stored in the storage device. , 4 and the bucket angle θ when boom 1 is rotating. The difference △θ.

This is a second computing unit that computes. And K is the second arithmetic unit j
〇〇 to the bucket angle deviation calculated by L (constant)
The third arithmetic unit that multiplies, I! , is linked to switch i, and the bucket angle deviation signal is +/△θ only when the bucket operating lever C is in the neutral position. The switch that outputs m is the bucket angle deviation signal, ・△θ. This is an amplifier that amplifies the signal 1 (q) and outputs a signal 1 (q) that operates the bucket angle correction solenoid valve e. When the bucket operating lever C becomes neutral, the switch i is turned on by the signal from the bucket neutral sensor d.
Bucket absolute angle θ. is stored in a storage device, and when the boom 1 rotates, the bucket target holding angle θ is stored in the storage device. Absolute angle θ of bucket 2 relative to 9
. changes, and the second arithmetic unit j and third arithmetic unit k produce a bucket angle deviation signal of 1.80. is calculated, the bucket absolute angle θ. is the target holding angle θ. An output signal 1 (q) is outputted to the bucket angle correction solenoid valve e via the amplifier m so that the bucket angular velocity is set to an appropriate value so that the difference with □ is eliminated. As described above, in the conventional control method shown in FIG. 5, the bucket angle deviation Δθ is controlled to maintain the angle of the bucket 2 constant even when the boom 1 rotates. The deviation signal is proportional to 1・△θ. It is controlled by.

(Problems to be Solved by the Invention) In the conventional bucket angle control method shown in FIG. 5 above, the bucket angle is corrected based on the deviation of the actual bucket angle from the target bucket holding angle. Because it obtains angular velocity, it always follows the target bucket angle with a delay.1 For example, when lowering the boom, the boom lowering speed increases due to the weight of the work equipment and cargo, and furthermore, the engine speed is low and the oil pressure is low. When the bucket angle must be corrected when the pump discharge volume is low.

The ability to follow the bucket angle while the boom is lowering may deteriorate, resulting in a large bucket angle deviation. This problem will be explained below using the graph of FIG. In FIG. 4, Xo is an example of the bucket angle locus of the conventional link only, and it can be seen that it deviates greatly from the ideal bucket angle locus indicated by X. X+ is an example of the bucket angle locus according to the conventional control method shown in FIG.

At the same time, this xl also deviates slightly from the x.

Bucket angle θ in the right half (second half of boom rotation) range of the horizontal axis (indicating boom angle θ2).

indicates a tilt from backwards to forwards. In this way, when the bucket cutting edge is tilted forward from the target, it is dangerous because there is a possibility that the load may fall. In addition, if the gain of the control system (to the constant shown in Figure 5) is increased to reduce the amount of deviation from the ideal bucket angle trajectory This poses a major problem in that it causes shock and hunting.

(Means and operations for solving the problem) This invention was made in view of the above points, and includes a boom that moves up and down with respect to the vehicle body, a bucket that tilts back and forth at the tip of the boom, and a boom that moves up and down with respect to the vehicle body. In a vehicle work equipment device equipped with a boom cylinder that rotates and a bucket cylinder that tilts a bucket, detecting a boom angle and a bucket angle,
A control means is provided which calculates the amount of deviation in the bucket angle caused by the link mechanism due to the vertical movement of the boom, and outputs a bucket angle correction signal according to the amount of deviation.

The target bucket angle θ is -Iθ21 in accordance with the boom angular velocity θ2 while the boom is moving up and down. By setting the control target to tilt backward relative to the wing, the bucket angle during boom rotation is the target angle θ at the start of boom rotation. , it always changes by tilting backwards.

(Example) Next, one embodiment of the present invention will be described based on the drawings.

FIG. 2(a) is an explanatory diagram of the operation of one embodiment of the bucket angle control method according to the present invention, and parts that operate in the same way as the conventional method shown in FIG. 5 are given the same reference numerals. A detailed explanation will be omitted.

The following description will also be made with reference to FIG. In the figure, 21
22 is a differentiator that differentiates the output signal θ2 of the boom angle sensor 6 with respect to time t to calculate the boom angular velocity dθt/at(・θ2), and 22 is a coefficient for the absolute value 1θ21 of the boom angular velocity signal θ2 computed by the differentiator 21. The third computing unit 23 multiplies 2 by 2 to the bucket angle deviation signal computed by the second computing unit j. A fourth arithmetic unit 24 adds the correction signal K...1 纺1 calculated by the third arithmetic unit 22;
! 1) is a fifth arithmetic unit that multiplies the coefficient by three.

In the bucket angle control method shown in FIG. 2(a), when the bucket operating lever C becomes neutral, the switch i is turned on by a signal from the bucket neutral sensor d, and the bucket angle is set to θ. is the target holding angle θ of the bucket by the storage device.
. When the boom 1 rotates, the bucket target holding angle θ is stored by the storage device. 8, the bucket absolute angle θ. changes, and the second arithmetic unit j generates a bucket angle deviation signal △θ. is calculated. At the same time, the differentiator 21 differentiates the boom angle θ2 to calculate the boom angular velocity θ2, and the third calculator 22 calculates 2·1θ21 on the bucket angle correction signal determined by the boom angular velocity θ2 to obtain the bucket angle deviation signal Δθ. is added in the fourth arithmetic unit 23.

With this, the target bucket angle θ is determined. While the boom 1 is rotating with respect to M, the bucket angle correction target is set to a position upward by .multidot.1θ21 in the correction signal. When the boom l stops, the original target angle θ is restored. actual bucket absolute angle θ. The difference between the bucket angle and the bucket angle becomes 0 and the bucket angle becomes θ. , is maintained.

The bucket cutting edge locus according to the bucket angle control method according to the above-mentioned FIG. 2 (al) is indicated by x2 in FIG.

This X2 is because the control target is placed on the backward tilting side with respect to the target bucket angle θOH by 2·1θ21 at the correction angle according to the boom angular velocity b2 as shown in the figure.

The bucket trajectory x 2 during one boom rotation is the target angle θ at the boom rotation starting point A. Since the bucket 8 is always tilted backwards, there is no fear that the cargo in the bucket 2 will fall.

FIG. 2(b) shows a flowchart of the bucket control method according to FIG. 2(al).

FIG. 3 shows another embodiment of the bucket angle control method according to the present invention, in which reference numeral 25 indicates a bucket cylinder 4 and a hydraulic pump b.
A solenoid valve installed between the

26 is an electric lever for operating the bucket, which outputs a signal proportional to the amount of lever operation. Reference numeral 27 denotes an amplifier that inputs and amplifies the output signal of the electric lever 26 and outputs a control signal to the electromagnetic valve 25. When the bucket is not operated in the neutral state, the switch 1 is turned ON and an output signal corresponding to the bucket angle correction signal is output to the solenoid valve 25, as in Fig. 2(a), and during the bucket operation, the switch β is OFF. The solenoid valve operates in response to the output signal of the electric lever 26. In this embodiment, since the operation of the bucket 2 is controlled by an electric lever 26, there is no need to provide a correction solenoid valve e and a bucket neutral sensor d as in the embodiment shown in Fig. 2+a). By simply adding 3 (Δθo+Kz·1θ21) to the output signal from the lever 26 and the correction signal, control similar to that of the embodiment shown in FIG. 2 (al) can be achieved.

(Effect of the invention) This invention is constructed as described above in detail.

The bucket angle during boom rotation can be controlled very close to the target bucket holding angle, and at the same time, the bucket angle is controlled to be tilted backwards compared to the target bucket holding angle, resulting in a delay in the response of the control system and insufficient hydraulic pump discharge, resulting in poor control accuracy. This has the great effect of allowing the bucket cargo to be raised and lowered safely even when the load drops.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the detection part in the method for controlling the bucket angle of a working machine of a shovel loader according to the present invention, and FIG. 2 (
a) is an explanatory diagram of the operation of one embodiment of the bucket angle control method according to the present invention, FIG. 2(b) is a flowchart of the bucket control method according to FIG. 2(a), and FIG. 3 is an explanatory diagram of the operation of another embodiment. figure. FIG. 4 is an explanatory graph showing the trajectory of the bucket angle with respect to the boom angle, and FIG. 5 shows a conventional one. ■...Boom, 2...Bucket. 3...Boom cylinder, 4...Bucket cylinder. 21... Differentiator, 22... Third computing unit. 23...Fourth computing unit, 24...Fifth computing unit. e... Solenoid valve for bucket angle correction.

Claims (1)

[Claims] In a work equipment system for a vehicle that includes a boom that moves up and down relative to the vehicle body, a bucket that tilts back and forth at the tip of the boom, a boom cylinder that rotates the boom, and a bucket cylinder that tilts the bucket, the boom angle and Detects the bucket angle and calculates the deviation amount by which the bucket angle changes due to the link mechanism due to the vertical movement of the boom.
A control means is provided for outputting a bucket angle correction signal according to the amount of deviation, and a control means is provided to output a bucket angle correction signal according to the amount of deviation, and the bucket angle correction signal is configured to cause the bucket to be directed upward relative to the actual amount of deviation, depending on the boom angular velocity while the boom is moving up and down. A bucket angle control method characterized by adding control signals.