JPS61296405A - Positioning control device for working machine of construction vehicle - Google Patents

Abstract

PURPOSE:To simplify the titled device, to reduce the cost of the device and to improve operability at the time of manual operation and control accuracy at the time of automatic control by forming a pilot hydraulic switching valve in a main hydraulic circuit and using the valve for both manual and automatic control. CONSTITUTION:A controller 21 inputs a signal + or -es from a computing element 17 in an automatic control circuit 13 and a signal + or -es' from a manual operation circuit 20, discriminates whether the input is manual or automatic and sends a signal -es or -es' or +es or +es' to an electromagnetically proportional pressure reducing valve 9 or 10 on the basis of the positive/negative of the signal. The valves 9, 10 lead primary pressure from primary side conduits 22, 23 and output hydraulic signals to pilot conduits 7, 8 in accordance with the signals + or -es, + or -es' to move the spool of a pilot hydraulic switching valve 3 and switch the hydraulic feeding direction from the valve 3 to the conduits 5, 6, so that fluidity is controlled by the area of the spool opening. In case of manual operation, a non-sensitive band specific to the spool valve is left. At the time of automatic control, the non-sensitive band is cut off to execute control.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a positioning control device for a working machine in a construction vehicle such as a hydraulic excavator, which can be controlled efficiently either automatically or manually.

(Prior art) Conventionally, as a means of automating working equipment of construction vehicles such as hydraulic excavators, the current position of the working equipment is detected and a flow control signal is generated according to the deviation between the detected value and a preset setting value. A device that outputs a flow rate control signal and operates a hydraulic control valve based on the flow control signal to control the position of the working machine (for example, Japanese Patent Application Laid-Open No. 1986-
45469) is known.

However, the above-mentioned conventional control device has a manual switching valve that is manually switched in the main circuit of the hydraulic circuit and a hydraulic control valve (proportional control valve) for automatic control, and the flow rate sent from the control circuit during automatic control. The hydraulic control valve is directly controlled by a control signal, and the flow controlled by the hydraulic control valve is supplied to the cylinder via a manual switching valve to control the position of the working machine. Therefore, the hydraulic circuit requires two major valves, a manual switching valve and a hydraulic control valve, as main control valves, resulting in a complicated circuit configuration and increased costs.

In addition, during automatic control, the manual switching valve is located downstream of the hydraulic control valve and only functions as a passage, which is extremely uneconomical and causes problems such as pressure a, reducing control accuracy. do. However, since the hydraulic control valve of a large boat installed in the main circuit is directly controlled, even if a proportional control valve is used, delicate control is difficult. Since the control signal is not output in that dead band width, if the control area based on the position deviation of the work equipment is in the dead band of this hydraulic control valve, the control will not be completed even if the feedback control is repeated. , a steady-state deviation always occurs. In order to improve control accuracy, it is possible to use a nervo valve as the hydraulic control valve, but this would increase the cost and have poor environmental resistance (against dirt, oil temperature, and viscosity changes). , there is a problem with control stability.

(Object of the Invention) The present invention has been made to solve the above conventional problems, and uses a pilot hydraulic switching valve that is cheaper than conventional proportional control valves and servo valves to convert this hydraulic switching valve into a manual hydraulic switching valve. This enables it to be used both for automatic control and for automatic control, simplifying the hydraulic circuit groove configuration and reducing costs.It also improves operability during manual operation, while achieving high precision without steady-state deviation during self-8 control. The present invention provides a work equipment positioning control device for a construction vehicle that can perform positioning control.

(Structure of the Invention) The present invention includes a hydraulic actuator that operates a work machine;
A pilot hydraulic switching valve that controls the supply of pressure oil to a hydraulic actuator, an electromagnetic proportional pressure reducing valve that controls the spool position of the hydraulic switching valve using pilot pressure, an automatic control circuit that sends a control signal to the electromagnetic proportional pressure reducing valve, and The automatic control circuit includes a detector that detects the current position of the work equipment, a signal generator that outputs a target position signal of the work equipment, and a spool position and opening area of the hydraulic switching valve. and a storage device that stores the relationship between the two, and calculates the deviation between the work machine current position signal from the detector and the work machine target position No. 15 from the signal generator, and also calculates the deviation between the deviation and the memory value stored in the storage device. and a computing unit that outputs a control signal corresponding to the required stroke of the spool of the hydraulic switching valve based on the amount of operation of the manual operating means. J: which outputs a signal, and is characterized in that it is configured to send a signal from the automatic control circuit and a signal from the manual control circuit to the electromagnetic proportional pressure reducing valve via the controller. .

That is, in the present invention, one hydraulic switching valve is installed in the main hydraulic circuit, and this hydraulic switching valve is controlled by a hydraulic signal from an electromagnetic proportional pressure reducing valve. It is possible to operate using either an electrical signal sent from a manual operating means such as an operating lever, or an electrical operating signal sent from a manual operating means such as an operating lever. During control, control is performed without a dead zone, making it possible to control high viscosity without steady-state deviations.

(Example) In Figure 1, 1 is the boom of a hydraulic cylinder (Structure 11)
, 2 indicates a cylinder (hydraulic actuator) that raises and raises the boom 1. Reference numeral 3 denotes a hydraulic pressure valve, which is installed in the main hydraulic line 4, and when this valve 3 is switched, the line 4 is
Pressure oil is supplied and discharged from the cylinder 2 through pipes 5 and 6,
The cylinder 2 is expanded and contracted to raise and lower the boom 1. This hydraulic switching valve 3 uses a spool valve that is switched by pilot pressure, and in order to switch this valve 3, an electromagnetic proportional pressure reducing valve 9.10 that sends a hydraulic signal to the pilot pipes 7 and 8 is used. The following control means are used to operate the pressure reducing valves 9.10.

'1j, that is, 11 is a detector, which detects the position (elevation angle) of the boom 1 as the working machine, and is composed of, for example, a potentiometer, and is also a detector that connects the boom 1 to the base machine (not shown). established in
A signal θ corresponding to the current position of the boom 1 is output. Note that the detector 11 may be provided at the pivot portion of the cylinder 2 with respect to the base machine or on the rod of the cylinder 2.

Reference numeral 12 denotes a target position signal generator, which outputs a signal θ0 corresponding to the target position to which the boom 1 should be raised or raised. In this case, when performing combined work using the boom 1 and the arm, such as horizontal extrusion of packets or circular excavation, the arm should be moved so that the boom 1 follows the movement of the arm and moves up and down.
The required moving group of boom 1 calculated based on the distance is sequentially output at the target position and j. Note that when the boom 1 works alone, a preset dump position, excavation position, or the like is output as a target position. This target position can be set arbitrarily.

13 is the main part of the automatic control circuit, arithmetic unit 14゜15.1
6.17 and a storage device 18 (this main part and the target position signal generator 12 may be included in a micro combi coater).

Based on the current position signal 0 of the boom 1 outputted from the detector 11 and the target position signal θ0 of the boom 1 outputted from the signal generator 12, the calculator 14 calculates both signals 0. Oo
, and outputs a signal eθ (-〇〇-〇) corresponding to the deviation. The calculator 15 calculates the flow rate necessary to operate the cylinder 2 to the target position by multiplying the position deviation signal eθ by a proportionality constant kO, etc., and generates a signal eq (=eθ・kθ) corresponding to the required flow rate. Output. The computing unit 16 calculates the necessary interval [1 area] of the spool of the hydraulic switching valve 3 corresponding to the above-mentioned required flow rate by dividing the above-mentioned required flow rate equivalent signal eq by the proportionality constant viI<a, and calculates the required opening area according to the required opening area. A signal ea (=eq/kq) is output.

On the other hand, the characteristics of the hydraulic pressure switching valve 3 are stored in the storage device 18 . In this case, there is a relationship between the spool stroke S of the hl+pressure switching valve 3 and the opening area a as shown in FIG. The sign of the opening area indicates the switching direction. This hydraulic switching valve 3 also has a small range of spool stroke S (0
≧S≦S1, 0≧S≧-31) is the dead zone, and the spool stroke S cannot be changed within this range. Even if the opening area a
The control cannot be overridden.

Therefore, in the present invention, the characteristics of the hydraulic switching valve 3 shown in FIG. 2 are changed to the relationship shown in FIG. The required spool strike [1-riS] can be immediately determined by calculating backward from the opening area a.

The opening unit 17 calculates the required stroke of the spool of the hydraulic switching valve 3 based on the required opening area equivalent signal ea outputted from the calculation unit 16 and the stored value stored in the storage device 18, and calculates the required stroke of the spool of the hydraulic switching valve 3. A signal es corresponding to the loaf is output to the necessary station 1. In this case, depending on whether the boom 11 is raised or lowered, the
Outputs negative 4E±es.

The manual operation circuit 20 converts the operation amount of a manual operation means such as the operation lever 19 into an electric signal using a potentiometer or the like, and controls the spool of the hydraulic switching valve 3 according to the operation direction and the operation claw as shown in FIG. A signal eS' for controlling according to the characteristics is output.

In this case as well, positive and negative signals ±eS' are output in accordance with the raising and lowering of the boom 1. However, the control signal is output from this manual operation circuit while leaving the dead zone peculiar to the spool valve.

The controller 21 is the arithmetic unit 1 of the automatic i and II control circuits.
The signal ±aS from 7 and the signal ± from the manual operation circuit 20
Input es' and determine whether it is automatic or manual, and also determine whether the signal is positive or negative, that is, whether the boom is raised or lowered, and when lowering the boom, the signal -es or -es' is set to N magnetic proportion. Press the signal on the pressure reducing valve 9 when raising the boom.
Or +e S ' is sent to the electromagnetic proportional pressure reducing valve 10. NaJ
3. To prevent danger, the signal from the manual operation circuit 20 is given priority over the signal from the automatic control circuit and the electromagnetic proportional pressure reducing valve 9,
It is set to be sent to 10.

The electromagnetic proportional pressure reducing valves 9 and 10 introduce primary pressure from their primary side pipes 22 and 23, and respond to electrical signals sent from the controller 21 such as es, -es or +es', -es.
' A hydraulic signal (pilot pressure) is output to the pilot pipes 7 and 8, and this hydraulic signal controls the hydraulic switching valve 3.
The spool is moved to switch the supply direction of pressure oil from the facing valve 3 to the pipes 5 and 6, and the flow rate is controlled by the spool opening area.

In the above configuration, manual operation V "poetry" requires operation lever 1.
9, the manual operation circuit 20 outputs a spool stroke control signal es' corresponding to the operating direction and operation interval (angle) of the operating lever 19, and the controller 21 outputs the positive and negative signals ±es'. In other words, it is determined whether the boom 1 is to be raised or lowered, and the signal es' or -es' is sent to the electromagnetic proportional pressure reducing valve 9 or 10 to operate the opposite valve, and from this valve 9 or 10 to the pipe line 7 or 8.
A pilot pipe is guided to the pipe, and the hydraulic switching valve 3 is switched by the pilot pressure, and the pipe 4 is connected to the pipe 5,
Pressure oil is supplied to and discharged from the cylinder 2 via the cylinder 6, and the cylinder 2 is expanded and contracted to raise and lower the boom 1. During this manual operation, the hydraulic switching valve 3 is controlled according to the characteristics shown in FIG. 2 by operating the operating lever 19, leaving a dead zone. Note that during manual operation, it is easier to operate if there is a dead zone, and therefore, the operability during manual operation can be improved.

Next, to explain automatic control, the signal generator 12
The target position signal θ0 of the boom 1 is outputted from the detector 11, and the current position of the boom 1 is detected by the detector 11 and its current position signal θ is outputted, and both signals θ0. θ is input to the calculator 14.

Then, the computing unit 14 sequentially generates a deviation signal eθ between the target position and the current position, the computing unit 15 generates a signal equivalent to the required flow rate for driving the cylinder 2 eqS, and the computing unit 16 sequentially generates a signal ea equivalent to the required opening area of the spool of the switching valve. At the same time, the arithmetic unit 17 calculates and outputs the required opening area equivalent signal ea and the memory W! A signal es corresponding to the required stroke of the spool of the hydraulic switching valve 3 is calculated and outputted based on the stored value stored in the controller 118 (see FIG. 3), and the signal eS corresponding to the required stroke is sent to the controller 21.

Here, when it is desired to lower the boom 1 from a high position to the target position (θ>Oo), a negative deviation signal -〇〇 is output from the calculator 14, and the controller 2
1, a negative required stroke equivalent signal -es is sent. Then, the controller 21 determines whether the required stroke equivalent signal -es is positive or negative, that is, whether the boom is up or down (in this case, down), and the signal es is sent to the electromagnetic proportional pressure reducing valve 9 for lowering the boom 1. The directing valve 9 is operated, pilot pressure is guided from this valve 9 to the pipe line 7, the hydraulic pressure switching valve 3 is switched by the pilot pressure, and the rod side oil chamber of the cylinder 2 is transferred from the pipe line 4 to the pipe line 5. Pressure oil is supplied to the cylinder 2, the cylinder 2 is retracted, and the boom 1 is lowered.

At this point, the pilot pressure guided from the electromagnetic proportional pressure reducing valve 9 to the pipe line 7 is controlled according to the magnitude of the required stroke equivalent signal -es, and the spool stroke of the hydraulic switching valve 3 is controlled to supply the pressure to the cylinder 2. In other words, the contraction and expansion of the cylinder 2 and the lowering and lowering of the boom 1 are controlled. In this case, the required stroke is equivalent to No. 5-es
is calculated based on the required aperture area equivalent signal -ea calculated by modifying the -F2 deviation signal -〇〇 and the stored value stored in the storage device 18. As shown in , since the oil pressure V is stored with the dead zone of the change valve 3 cut off as shown in FIG.
is output and control starts.

Then, the above control is repeated until the deviation signal -ea becomes 0, and feedback control is performed, and at the time of this control, efficient and highly accurate control is performed without a dead zone. After that, when the deviation signal -ea becomes O,
The hydraulic switching valve 3 is returned to the neutral position, the cylinder 2 is stopped, and the boom 1 is stopped and held at the target position.

In addition, when J3 is in the above-mentioned automatic control and, for example, performs horizontal excavation of the packet while lowering the boom 1 following the push of the arm in combined work using the arm and boom 1, the position and amount of movement of the arm are determined by the signal generator 12. The signal generator 12 calculates the necessary movement distance of the boom 1 corresponding to the movement distance of the arm, and calculates the required movement! r! The IJ suspension is output as the target position signal θ0, and the above control is performed.

Following this, boom 1 is lowered following the push of the rear arm,
Automatic horizontal extrusion of the packet takes place.

In addition, when raising the boom 1 from a low position to a high target position, contrary to the above, a positive deviation signal 10eO is output from the operator f3, and thereafter, the operator 17 is operated in the same manner as above.
However, a positive required stroke equivalent signal - eS is output,
Therefore, the signal +eS is sent from the controller 21 to the electromagnetic proportional pressure reducing valve 10 for raising the boom, and
A pilot pressure corresponding to the above-mentioned Ig No. 10es is introduced into the conduit 8 through the direct valve 1o, the hydraulic pressure switching valve 3 is switched, the cylinder 2 is extended, and the boom is controlled to be raised.

In this way, during automatic control, highly accurate control without steady-state deviation can be performed by controlling the dead zone of the hydraulic pressure switching valve 3 by cutting it.

In addition, in the above control, when rewriting the characteristic of the hydraulic switching valve 3 shown in FIG. 2 to the characteristic shown in FIG. 3 and storing it in the storage device 18, the characteristic is rewritten to a simple linear characteristic as shown in FIG. 4 and stored. It is also possible to do so, and in this case as well, the effect can be almost the same as that described above.

Further, the arithmetic unit 16 generates a required opening area equivalent signal ea
When calculating, instead of measuring the supply pressure Ps from the pipe line 4 and the pressure Pd inside the cylinder 2, and dividing the required flow ω equivalent signal eq by the proportionality constant akq, a constant 1 that takes the above pressure into account is calculated.
<a-4=ground ball] By dividing by n, a more accurate required opening area equivalent @ea can be obtained, and more accurate control can be performed.

In the above embodiment, the working machine is the boom 1 of a hydraulic excavator.
For example, boom elevation cylinder 2 is used as a hydraulic actuator.
Although the work equipment is not limited to the boom 1, it may also be an arm, a packet, a swing or a winch of a crane.
The hydraulic actuator is not limited to the cylinder 2, but may also be a hydraulic motor. This thin ice invention can be applied to various construction machines other than the above-mentioned hydraulic excavators and cranes.

(Effects of the Invention) As described above, the present invention provides one pilot hydraulic switching valve in the main hydraulic circuit, controls this hydraulic switching valve by a hydraulic signal from an electromagnetic proportional pressure reducing valve, and The electromagnetic proportional pressure reducing valve can be operated by either an electric signal sent from an automatic control circuit or an electric operation signal sent from a manual operation means such as an operation lever,
This makes it possible to simplify the circuit configuration and reduce costs. Moreover, during manual operation, the dead zone peculiar to spool valves is left to improve operability, while during automatic control, control is performed with the dead zone to a minimum, allowing control with a high degree of R without generating steady-state deviations. It is.

[Brief explanation of the drawing]

Fig. 1 is a sized block diagram of an embodiment of the present invention, Fig. 2 is a characteristic diagram of the hydraulic switching valve, Fig. 3 is a characteristic diagram of the hydraulic switching valve stored in the upper storage device, and Fig. 4 is a diagram of another hydraulic switching valve. FIG. 3 is a diagram corresponding to FIG. 3 showing an example. 1... Boom (working), 2... Cylinder (hydraulic actuator), 3... Pilot hydraulic switching valve, 9° 10... Electromagnetic proportional pressure reducing valve, 11... Current position detector, 12 ...Target position signal generator, 13...Main part of automatic control circuit, 14.15.16.17...Arithmetic unit,
18...Storage device, 19...Operation lever (manual operation means), 20...Manual operation circuit, 21...Controller. Patent applicant: Kobe Steel, Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Chief 1
) Masayuki Patent Attorney Yasuo Itaya Figure 2

Claims (1)

[Scope of Claims] 1. A hydraulic actuator that operates a working machine, a pilot hydraulic switching valve that controls the supply of pressure oil to the hydraulic actuator, and an electromagnetic proportional pressure reduction that controls the spool position of this hydraulic switching valve using pilot pressure. valve, and an automatic control circuit and a manual operation circuit that send control signals to the electromagnetic proportional pressure reducing valve, and the automatic control circuit includes a detector that detects the current position of the work equipment and outputs a target position signal of the work equipment. a signal generator that stores the relationship between the spool position and the opening area of the hydraulic switching valve, and a deviation between the work equipment current position signal from the detector and the work equipment target position signal from the signal generator. and a computing unit that outputs a control signal corresponding to the required stroke of the spool of the hydraulic switching valve based on the above deviation and the stored value stored in the storage device, and the manual operation circuit operates the manual operation means. It is configured to output a control signal corresponding to the required stroke of the spool of the hydraulic switching valve according to the amount, and the signal from the automatic control circuit and the signal from the manual control circuit are sent to the electromagnetic proportional pressure reducing valve via the controller. A working machine positioning control device for a construction vehicle, characterized in that it is configured to send. 2. The construction vehicle according to claim 1, wherein the storage device rewrites and stores the relationship between the spool position and the opening area of the hydraulic switching valve into a relationship that determines the spool from the opening area. work equipment positioning control device. 3. The computing unit includes a computing unit that computes the required flow rate of the hydraulic actuator based on the deviation between the work machine current position signal from the detector and the work machine target position signal from the signal generator; a computing unit that calculates the required opening area of the spool of the hydraulic switching valve based on the above-mentioned required opening area and the memory value stored in the storage device; A work equipment positioning control device for a construction vehicle according to claim 1 or 2, characterized in that the device comprises: