RU136055U1 - AUTOMATIC CONTROL HYDRAULIC DRIVE FOR SINGLE BUCKET EXCAVATOR - Google Patents

Abstract

The hydraulic drive control device for a single-bucket excavator consists of mechanical equipment, power hydraulic cylinders, control valves, solenoid electromagnets, characterized in that the device includes strain gauge pressure monitoring sensors in the nodal connections of the power hydraulic cylinders, resistance transducers into an electrical signal and an onboard logic programmable for microprocessor-based digging depth the controller, while the pressure sensors through the signal converters e They are electrically connected to “Input 1” and “Input 2” of the on-board logic microprocessor controller, and the output signals processed by it according to a given program from “Output 1”, “Output 2” and “Output 3” are electrically connected to the electromechanical hydraulic drive of the power hydraulic cylinders kinematically coupled with mechanical equipment of a single bucket excavator.

Description

The utility model relates to construction, in particular, to maintaining optimal values of the cutting angle of the soil and digging depth (chip thickness) of the soil under the design mark during the construction of pits and trenches for laying oil and gas pipelines, pipelines for supplying water and steam, cables of high-voltage power lines and other

1. It is known (analogue) hydromechanical device with a copy system SU (AS No. 135418, AS No. 142307).

When using this device, the working equipment of the excavator is controlled by the operator manually using the combined control handle, and the specified digging path is provided by the copying device.

The disadvantages of hydromechanical automated control devices are determined by the limited capabilities of mechanical systems. In these systems, automatic control is carried out by only one movement (by turning the boom) by turning the handle with a constant position of the bucket relative to the handle.

This drawback leads to a change in the cutting angle during the digging process, which, in addition to increasing energy consumption and lowering the layout quality, causes a significant reduction in the digging working area in those sections of the bucket path where the cutting angle reaches a negative value and soil excavation becomes impossible.

In addition, with such devices, a significant part of the kinematically accessible working area of the excavator cannot be used during planning works, since the speed of the corrective movement of the boom may not be sufficient to ensure rectilinear movement of the bucket at full speed of rotation of the handle.

The disadvantage of these devices is also the need for certain alterations in the design of the excavator and, most importantly, its hydraulic control system.

2. The technical solution “Electromechanical servo device for controlling the hydraulic drive of working equipment for a single bucket excavator is known, see SU (ac No. 334342 of 03/30/1972 and No. 338603 of 05/15/1972, class E02f, 9/20), (the closest analogue is a prototype device automatic control of the hydraulic drive of a single bucket excavator). This device is made in the form of a copy-tracking system that provides forced movement of the cutting edge of the bucket along a predetermined path defined by templates installed on the copy panel.

A disadvantage of the known device is the low dynamic characteristics of the servo system due to which a hydraulic shock occurs at the moment of setting the mismatch angle, which leads to fluctuations of the valve, transmitted to the control handle of the mechanical equipment of the excavator, which introduce significant errors into the modes of soil digging. In addition, during operation of the machine due to the wear of the hydraulic drive elements, the servo control system itself goes out of operation.

3. For example, in the well-known analogue according to Austrian patent No. 430739 "Device for stabilizing the position of the copying mechanism of earth-moving earth moving machines" containing a combined control lever, a copy panel with templates and a tracking device that drives the elements of the working equipment and combined control lever, relatively templates on the copy panel, which provides a given trajectory of the bucket of the excavator.

The disadvantage of this device is that the reference system of the geometric parameters of the bucket trajectory is tied to the machine itself and, therefore, when moving it from one grapple to another along an uneven surface, the specified bucket trajectory is provided with large errors that are incompatible with the design requirements.

4. In the known analogues of US patent No. 2973593 class. 37-144 "System for stabilizing the position of the copier of earth-moving machinery of cyclic action" and No. 3583585. The disadvantage of the known system according to patent No. 2973593 class. 37-144 is that in the system, the required longitudinal movement of the working body of the digging machine is set using an infrared light beam created specifically for this purpose by the intended equipment.

This technical solution provides with the infrared beam only the rectilinear movement of the bucket of the excavator and does not provide a given variable digging depth at various pressures in the joints of the mechanical equipment.

In addition, the creation of an infrared beam requires the installation of additional complex equipment and the infrared beam introduces large errors when the machine moves on an uneven surface.

The objective of this utility model is to improve the control device for the hydraulic drive of a single-bucket excavator by introducing new technical means that provide a new principle for controlling pressure associated with digging depth in the nodes of mechanical equipment and an on-board microprocessor controller with software that automatically maintains the optimal specified cutting angle (digging depth ) along the entire trajectory of the bucket.

The purpose of this utility model is to provide the specified optimum cutting angle and soil digging depth to the design level by the working body of a single-bucket hydraulic excavator, which provides a reduction of up to 78% in the cost of cleaning and planning work, which allows to obtain flat bottom surfaces and slopes of trenches and ditches located on different levels and at different angles to the horizon; increase in operational productivity of a hydraulic excavator, due to the best filling of the bucket with soil; prevention of overloads of the working mechanisms of the machine and, as a consequence of this, an increase in its reliability and durability.

At the same time, the new technical solution of the automatic control device for the hydraulic drive of a single-bucket excavator is devoid of the disadvantages of the prototype and analogues associated with providing a predetermined only rectilinear digging path based on a copying mechanism that does not perform the basic functions of maintaining a given cutting angle and digging depth developed by the soil with a hydraulic excavator bucket.

Figure 1 shows the structural diagram of the proposed utility model.

The automatic control device for the hydraulic drive of a single-bucket excavator 18 contains an arrow 1, a handle 2 and a bucket 3, as well as their respective driving hydraulic cylinders 4, 5 and 6, includes two strain gauge sensors 7 and 9 for monitoring the pressure in the nodes of the articulation of the hydraulic cylinder 5 with the handle 2 and the hydraulic cylinder 6 with a bucket 3. Strain gauges 7 and 9 measure the active resistance depending on the actual pressure in the joints of the hydraulic cylinders 5, 6 and from the transducers 8 and 10 they signal a constant voltage to “Input 1” and “Input 2” microprocessor controller ((ЛМК) 17 (PCIARK), where Р - pressure, С - regulation, I - indicating device, A - signal lamp, R - registration (recorder), K - program. Output signals LMK 17, processed by adaptive according to the results of external factors from “Output 1”, “Output 2” and “Output 3”, the self-adjusting program is electrically connected to electromechanical drives (solenoids) 11, 13, 15, which supply liquid through the control valves 12, 14, 16 to the compression chambers I or II power hydraulic cylinders 4, 5, 6 for movement (raising or lowering ) kinematically coupled with mechanical equipment 1, 2, 3 of a single bucket excavator 18.

The operation of the drive control device is as follows. At the beginning of the digging process, the driver controller drives the bucket 3 in contact with the bottom face and includes a drive turning the handle 2 of the excavator 18 to dig. When in the process of digging the pressure reaches the preset value in the articulation unit of the hydraulic cylinder 5 of the handle 2 drive, determined by the resistance of the digging soil, the pressure control sensor 9 sends a signal to “Input 2” of the LMK 17 through the converter 10, which through the “Output 2” includes the solenoid of the electromechanical drive 15 , moving with the help of a hydraulic fluid (engine oil) the valve spool 16, which controls the movement of the power hydraulic cylinder 6. The hydraulic cylinder 6 will begin to rotate the bucket 3 in the direction of decreasing the cutting angle g Unt and this change will continue until such time as the pressure in the hydraulic cylinder unit 6 is below the set value the program of the microprocessor 17, which determines the cutting depth of the soil bucket 3.

In the event of a prolonged excess of pressure in the hydraulic cylinder unit 6, the load cell 7 sends a signal to the “Input 1” of the microprocessor 17 through the converter 8, and from its “Output 1” the converted signal gives the command to turn on the electromagnet 13 and the control valve 14 to raise the handle 2, changing the angle P , depending on the inclination of the cutting edge of the bucket 3, which corresponds to the depth of digging.

If the limiting pressure values occur simultaneously at the nodes of the hydraulic cylinders 5 and 6, which indicates too much digging depth (chip thickness), the load cells 7 and 9 through the transducers 8 and 10 will send a signal to both inputs simultaneously (“Input 1” and “Input 2”) microprocessor 17. The output signal from the “Output 3” of the microprocessor 17 is fed to the coil of the solenoid of the electromagnetic actuator 11, which acts on the valve 12, forcing the hydraulic cylinder 4 to raise (extend) the boom 1, changing the angle of inclination α. In this case, the digging depth will decrease, the pressure on the load cells 7 and 9 will decrease, the output signal to “Output 1” and “Output 2” of the microprocessor 17 will also decrease, which from “Output 1”, “Output 2”, “Output Z” will return the power cylinders 4, 5, 6 to its original state, providing the specified (according to the program) values of the angles α, β and the cutting angle γ.

LMK 17 at the “Input 1” and “Input 2” has elements of a short delay time (I ₃ = 2-3 s) for operation, which eliminates accidental short-term overloads of the working equipment of the hydraulic excavator 18.

The step-by-step regulation of the digging depth by the working mechanism 3 using power hydraulic cylinders according to the program: 6 → 5 → 4 → 0 is most effective, since it significantly reduces the number of cycles and the time for technological operations of deepening and deepening the bucket 3, which, in turn, increases productivity and the reliability of the mechanical equipment of the machine.

A microprocessor (MP) is a software-controlled computing device implemented on one or more large digital integrated circuits (LSI) having a large degree of integration (by receiving and generating control signals) due to the content of 1000 to 10000 in the LSI on a single semiconductor chip -40000 thousand electronic elements (diodes, transistors, amplifiers, resistors, capacitors).

To perform the tasks of converting, processing, storing input and generating output signals for controlling the actuators of the machine, the MP should include memory devices, devices for inputting information from sensitive elements and outputting controlled signals to actuators (interfaces). In the presence of these elements, a microprocessor device called a logical microprocessor controller (LMC), the purpose and functions of which are completely determined by the programs contained in the ROM and RAM. Fig. 2 shows: CDS - switchboard of input two-position signals; RAM - RAM: T - block of time delays; BL - logical processing unit; MF - binary counter of read-only memory addresses; BU - block generating control signals; ROM - read-only memory; RDS - a distributor of output (control) two-position signals; M1, M2 and M3 are trunk buses.

LMK is a microprocessor-based computing device designed primarily for control tasks. The individual elements (modules) are interconnected using the busbars M1, M2 and M3.

The information storage functions are performed by the LMK storage devices: ROM - read-only memory devices and RAM - online (current) storage devices that determine the methods of information transfer between the MP and peripheral devices of the control object. ROMs are used to store programs that do not change during the processing of information. In RAM, the MP reads and writes information that changes during the operation of the control system.

The interface defines a set of methods and means for interfacing address, information and control communication lines. The following types of interface are provided in LMK: microprocessor, memory, input-output devices, communication with the control object (with strain gauges and hydraulic cylinders).

Logical control of the paintwork is performed by the control unit BU, which implements the main control function by selecting program commands.

The implementation of the LMK program is a sequence of individual commands related to the depth L of the bucket cutting, which functionally depends on the forces P at the joints of the mechanical links of the hydraulic excavator (Fig. 3).

LMK produces: conversion, processing, storage of the input signal [R = f (p)] (Fig. 3), coming from the bridge circuit of the converters 8, 10, which in the form of voltage is supplied to Input 1 and Input 2.

After amplification of the signal, a control command is generated from Output 1, Output 2 and Output 3 by actuators 4, 5, 6 in real time in accordance with a fixed set of applied work programs that determine the maximum digging depths by the working mechanism of a hydraulic excavator.

The switch of the input two-position (discrete and analog) signals of the CDS is a normalizer, which is necessary for converting the signals coming from the bridge circuit with load cells to Input 1 and Input 2 of different amplitude and polarity into a unified signal, which provides optimal output from Output 1, Output 2 and Output 3 the operation of actuators 4, 5, 6 to maintain a given digging depth by the working body of the machine.

In general, LMK solves the following main tasks:

- determination of current and forecasted values of the controlled parameters of the digging mode: cutting depth L, and angles a, P, at the rotation of the mechanical links of the working body of the machine;

- calculation of technological indicators, depending on the values of the measured parameters;

- an alarm about a violation of the process or the operation of the machine;

- registration of information on the implementation of specified technological parameters and operating modes of the mechanical equipment of a hydraulic excavator.

The carbon copy (hard) program does not provide optimal cutting angles, soil digging depths of trenches of gas and oil pipelines and the straightness of the machine, as this takes into account external influences: soil strength, cutting depth, unevenness of the developed surface, etc., controlled by pressure changes using strain gauges in nodes of articulation of hydraulic cylinders with a bucket handle.

Only an adaptive self-adjusting control system (adapting to previously unknown external influences), which is formed when pressure sensors 7 and 8 are introduced into the device for pressure control in the nodal connections of power hydraulic cylinders, resistance transducers 8 and 9 into an electrical signal and on-board logic are reprogrammable for a given depth digging the microprocessor controller 17, while the pressure sensor through the signal converters are electrically connected to "Input 1" and "B ode 2 "logic board microprocessor controller, and treated them for a given program to output signals" Output 1 "," Output 2 "and" Output 3 "are electrically connected through the electro-hydraulic valves with the hydraulic power cylinder is kinematically articulated mechanical equipment shovel.

A positive effect from the implementation of this device is achieved by providing the specified optimum cutting angle and soil digging depth to the design level by the working body of a single-bucket hydraulic excavator, which provides a reduction of up to 78% in the cost of cleaning and planning work, which allows to obtain flat bottom surfaces and slopes of trenches and pits located at different levels and at different angles to the horizon;

increasing the operational productivity of a hydraulic excavator, by best filling the bucket with soil; prevention of overloads of the working mechanisms of the machine and, as a consequence, an increase in its reliability and durability, in comparison with the well-known technical solution "Electromechanical tracking device for controlling the hydraulic drive of the working equipment of a single-bucket excavator (AS No. 334342 from 03/30/1972 and No. 338603 from 15.05 .1972, class E02f, 9/20), in which the tracking (hard copy), not taking into account external factors and has low efficiency, the control system is replaced by an adaptation system that allows for a higher level automatic control of mechanical equipment of a single-bucket hydraulic excavator. Such a self-adjusting automation system according to the program allows you to ensure the task.

Claims (1)

The hydraulic drive control device for a single-bucket excavator consists of mechanical equipment, power hydraulic cylinders, control valves, solenoid electromagnets, characterized in that the device includes strain gauge pressure monitoring sensors in the nodal connections of the power hydraulic cylinders, resistance transducers into an electrical signal and an onboard logic programmable for microprocessor-based digging depth the controller, while the pressure sensors through the signal converters e They are electrically connected to “Input 1” and “Input 2” of the on-board logic microprocessor controller, and the output signals processed by it according to a given program from “Output 1”, “Output 2” and “Output 3” are electrically connected to the electromechanical hydraulic drive of the power hydraulic cylinders kinematically coupled with mechanical equipment of a single bucket excavator.

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