JPS6254934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a bucket control method for a power shovel.

A power shovel is usually configured as shown in Figure 1. When carrying out work such as moving earth and sand scooped up by a bucket 1 to a truck or other location, conventionally, the boom 3, arm 2, and bucket 1 are operated. A person can operate each control lever (not shown) in the driver's seat.
During the work, he was careful not to let dirt, etc. fall from the bucket 1 through the hydraulic cylinders 6, 5, and 4. In this case, the operator must operate the three operating levers of each hydraulic cylinder at the same time, so unless the operator is very skilled, the operating speed of each member 1, 2, and 3 may be reduced, and the bucket 1 may be covered with dirt. This caused problems such as dropping the machine, which was unfavorable in terms of work efficiency.

The present invention solves the above-mentioned problems of the conventional power shovel, and provides a bucket control method for a power shovel that is quick and efficient without dropping the dirt etc. scooped up by the bucket, even if the operator is not an expert. This was proposed for the purpose of maintaining the bucket at a constant angle of attack with respect to the ground by manually operating the arm and boom of the power shovel.The system adds and subtracts the set bucket angle of attack, boom angle, and arm angle using an arithmetic circuit. The bucket angle deviation obtained by subtraction with the bucket angle is adjusted to obtain a signal equivalent to the distributor operation, and the bucket angular velocity target value obtained by subtracting the arm angular velocity and the boom angular velocity is then calculated as the bucket hydraulic cylinder pressure. Manually operate the arm and boom by compensating for the influence and using it as a feedforward signal, adding the signal equivalent to the distributor operation and the feedforward signal, and operating the distributor as the distributor operation signal. The present invention relates to a bucket control method for a power shovel, which is characterized in that the bucket can be operated accurately and stably at a constant angle of attack.

The present invention will be specifically explained below with reference to FIG. In the figure, 7 is a boom angle detector, 8 is an arm angle detector, 9 is a bucket angle of attack setter, 10 is a subtracter, 11 is an adder, 12 is a subtracter, 13 is an adjuster, and 14 is an arm angular velocity detector. vessel,
15 is a boom angular velocity detector, 16 is a subtracter, 17
is a feed forward signal compensator, 18 is an adder, 19 is a subtracter, 20 is a stroke control valve and drive amplifier, 21 is a distributor, 2
2 is a bucket hydraulic cylinder (corresponding to the hydraulic cylinder 4 in Fig. 1), 23 is a bucket angle detector, 24 is a bucket angular velocity detector, 25 is a regulator, 26 is a feed forward signal, and 27 is a bucket angle. A setting signal, 28 is a distributor drive command signal, and 29 is a load pressure detector, and the angles of the boom 3 and arm 2 driven by manual operation by the driver are detected by the boom angle detector 7 and the arm angle detector. 8, these detection signals are subtracted by a subtracter 10, this signal and the angle signal from the bucket angle of attack setter 9 are added together by an adder 11, and the output of this adder 11 is the bucket torque. This becomes the angle setting signal 27. The bucket angle setting signal 2
7 inputs the actual bucket angle from the bucket angle detector 23 to the subtracter 12, obtains a deviation signal by subtraction, inputs this deviation signal to the regulator 13, and uses it as one of the distributor drive signals. It's becoming like that.

Another one of the distributor drive signals is obtained as follows.

That is, the angular velocity of the arm 2 is determined by the arm angular velocity detector 14, and the angular velocity of the boom 3 is determined by the boom angular velocity detector 15, and these are subtracted by the subtractor 16. Find the required angular velocity of bucket 1. This signal is input to the feedforward signal compensator 17, and the load pressure detected by the load pressure detector 29 of the bucket hydraulic cylinder 22 is input, and this influence is corrected to output the distributor drive signal. The signals from the regulator 13 and the feed forward signal compensator 17 are input to the adder 18, the output of the adder 18 and the bucket angular velocity are obtained from the bucket angular velocity detector 24, and the output from the adder 18 and the bucket angular velocity are obtained from the regulator 25.
A bucket angular velocity feedback signal obtained by inputting the subtractor 19 is inputted to a subtracter 19, and as a result, a distributor drive command signal 28 is obtained. The feedforward signal compensator 17 corrects the target angular velocity of the bucket 1 for the influence on the load such as dirt and sand scooped by the bucket 1. In addition, the distributor drive command signal 28 obtained as described above is inputted to the stroke control valve and drive amplifier 20 that drive the distributor 21, whereby the distributor 21 is operated and the bucket hydraulic pressure is cylinder 2
Supply pressure oil to 2 and drain the oil to the drain,
The bucket 1 is maintained at a constant angle of attack and controlled to prevent soil and sand from spilling out.

In addition, the stroke control valve and drive amplifier 20
is a valve that outputs a displacement according to an input electric signal, and the same function can be obtained by using a servo valve and a servo cylinder instead.

Since the method of the present invention has the above-described structure and operation, according to the present invention, (1) the bucket is controlled to maintain a constant angle of attack with respect to the movement of the boom and arm of the power shovel; Therefore, there is no risk of dirt, etc. spilling out of the bucket, and work efficiency can be improved.

(2) In addition to the feedback control of the bucket angle of attack, a signal corresponding to the target value of the bucket angular velocity is added in a feed-forward manner, and the bucket load is compensated for, and bucket angular velocity feedback control is now performed. Therefore, stable and accurate bucket angle control can be performed.

The following practical effects can be mentioned.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a general conventional power shovel, and FIG. 2 is a schematic explanatory system diagram of an example of a device implementing the present invention. 1: Bucket, 2: Arm, 3: Boom, 9:
Bucket attack angle setting device, 14: Arm angular velocity detector, 15: Boom angular velocity detector, 22: Hydraulic cylinder for bucket, 24: Bucket angular velocity detector,
26: Feed forward signal, 27: Bucket angle setting signal, 29: Load pressure detector.

Claims (1)

[Scope of Claims] 1. When maintaining the bucket at a constant angle of attack with respect to the ground by manually operating the arm and boom of the power shovel, the bucket can be adjusted by adding and subtracting the set value of the bucket's attack angle, the boom angle, and the arm angle using an arithmetic circuit. The target angle is set as the target angle, and the bucket angle deviation obtained by subtraction from the bucket angle is adjusted to obtain a signal equivalent to the distributor operation, and the influence of the bucket hydraulic cylinder pressure is compensated for by subtracting the arm angular velocity and boom angular velocity to the target bucket angular velocity. By adding the signal equivalent to the distribution unit operation and the feed forward signal and operating the distribution unit as the distribution unit operation signal, the signal is constant for manual operation of the arm and boom. A bucket control method for a power shovel characterized by making it possible to accurately and stably operate the bucket at the angle of attack.