JPH05280501A - Electronic control device for hydraulic circuit - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a configuration of a control unit in an electronic control device for a hydraulic circuit, which is inexpensive to replace, facilitates production control, and does not cause a mismatch in control states or a combination error during assembly. [Structure] A control unit 11 which stores basic data performs data communication with the control units 7 and 10 in accordance with switching of control modes. The control unit 7 receives and inputs the basic data of the control mode at that time from the control unit 11, and performs a control calculation based on this and the pressure signal of the pressure detector 5 and the swash plate position signal of the swash plate detector 6 to perform the swash plate position. A swash plate drive signal is output to the controller 8. The discharge flow rate of the hydraulic pump 1 is controlled by this signal. The control unit 10 is the control unit 11
It receives and inputs basic data from, performs control calculation, and outputs a control signal to the solenoid valves 3L and 3R. The opening of the control valve 3 is controlled by this signal and the actuator 2
Alternatively, the direction and flow rate of the pressure oil to the tank 9 are controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic drive circuit used in a hydraulic machine such as a hydraulic excavator and a hydraulic crane, a control device such as a prime mover, and more particularly to a configuration of an electronic control device having a plurality of control units.

[0002]

2. Description of the Related Art In recent years, in construction machines such as hydraulic excavators and hydraulic cranes that drive a working device by a hydraulic drive system, hydraulic pressure is used for the purpose of improving functionality, improving operability, and saving energy for adapting to various works. Electronic control of drive units and prime movers is being promoted. FIG. 12 shows an example of an electronic control device for a hydraulic circuit.

This electronic control unit is connected between the hydraulic pump 1, a hydraulic actuator 2 driven by the pressure oil discharged from the hydraulic pump 1, and between the hydraulic pump 1 and the hydraulic actuator 2, and is supplied to the hydraulic actuator 2. A control valve 3 for controlling the flow rate of pressure oil, a control unit 12, a control unit 13, and a changeover switch 14.

In the hydraulic pump 1, signals from the pressure detector 5 and the swash plate position detector 6 are transmitted to the control unit 12,
The signal causes the control unit 12 to move the swash plate position control device 8
Through, the position of the swash plate 1a is controlled, and the displacement, that is, the discharge flow rate is controlled.

The control valve 3 receives signals from the control unit 13 by the operating lever 4 and its solenoid valves 3L and 3R receive the signals to control the opening thereof, and control the direction and flow rate of the pressure oil to the actuator 2 or the tank 9. ..

The changeover switch 14 instructs the control units 12 and 13 to change the control state, for example, the control in the normal mode or the control in the fine operation mode.

FIG. 13 shows the configuration of the control unit 12.
The control unit 12 receives the pressure signal pd of the pressure detector 5 and the swash plate position signal θ from the swash plate detector 6 and converts it into a digital signal, and a central processing unit (C).
PU) 21d and a read-only memory (ROM) for storing a control procedure program and basic data required for control
22d, a random access memory (RAM) 23d for temporarily storing a numerical value during calculation, an output interface (I / O) 24d, an amplifier 25 for outputting a swash plate drive signal to the swash plate control device 8, A digital input interface (D / I) 29d for inputting the switch signal Sw from the changeover switch 14 is included.

FIG. 14 shows the configuration of the control unit 13.
In the figure, the same parts as those of the control unit 12 are indicated by the same numbers as in FIG. The operation signal X of the operation lever 4 is converted into a digital signal by the A / D converter 20e. The digital switch signal Sw from the change-over switch 14 is input by the digital input interface (D / I) 29e. Further, the D / A converter 26e reconverts the digital signal into an analog signal, and these analog signals are amplified by the amplifier 28.
It is amplified by L and 28R and output to the solenoid valves 3L and 3R.

The ROM 22d of the control unit 12 is shown in FIG.
3 shows a flowchart of the control procedure stored in FIG. First,
In step 100, the pressure signal pd and the swash plate position signal θ are read via the A / D converter 20d. Next, in step 101, the switch signal Sw is read via the digital input interface (D / I) 29d. Then step 102
In step 23, the hydraulic pump target absorption torque Tr for normal mode control or fine operation mode control is set in the RAM 23d in accordance with the switch signal Sw. Further, in step 110, the target tilt angle θr is calculated by substituting the pressure signal pd and the value of the hydraulic pump target absorption torque Tr previously stored in the RAM 23d into the following equation.

Θr = C · Tr / pd Tr at this time has a unique value depending on the model using this hydraulic circuit and the switch signal Sw at that time. Next, in step 120, a drive signal is output to the swash plate control device 8 so that the swash plate position signal θ matches the target tilt angle θr.

FIG. 16 shows the ROM 22e of the control unit 13.
3 shows a flowchart of the control procedure stored in FIG. First,
In step 200, the operation signal X is read via the A / D converter 20e. Next, in step 201, the switch signal Sw is sent to the digital input interface (D / I) 29e.
Read through. Next, in step 202, the calculation coefficient Ky of the control in the normal mode or the control in the fine operation mode and the value Xo of the dead zone are set in the RAM 23e according to the switch signal Sw.
Set to. Next, in step 210, the operation signal X, the operation coefficient Ky previously stored in the RAM 23e, and the dead zone value X are stored.
Calculate the valve operation amounts Y1 and Y2 using o.

When X≥0 Y1 = Ky. (X-Xo) Y2 = 0 When X <0 Y1 = 0 Y2 = Ky. (| X | -Xo) At this time, Ky and Xo are the hydraulic circuits. It becomes a unique value depending on the model used and the switch signal Sw at that time. Next, in step 220, the valve operation amounts Y1 and Y2 are output via the D / A converter 26e and the amplifiers 28L and 28R.

[0013]

The control device having these configurations has the following five problems.

First, there are the following problems when the number of control units is plural or one. (1) Since the control units 12 and 13 perform all of the detection signal input, data processing, and device drive signal output, as described above, the A / D converter 20d or 20e,
Alternatively, an expensive input / output device such as the I / O interface 24d and an amplifier is required, and accordingly, a large-capacity power source and a large-area board are required, and the unit price of the control unit becomes expensive. Therefore, when changing the basic data to improve the performance, the expensive control unit 12 or 13 itself must be replaced each time, which is uneconomical.

Further, there are the following problems which occur when there are a plurality of control units. (2) The control units 12 and 13 differ in the basic data Tr, Ky, Xo used in the calculation as shown in FIGS. 15 and 16 depending on the model in which this hydraulic circuit is used.
Therefore, despite the common control program, it is necessary to prepare various types of control units for each model.
Production management becomes complicated.

(3) Since there are various types of control units for each model due to the reason (2) above, there is a possibility that the combination of the control units 12 and 13 may be mistaken during assembly.

(4) Control unit 12 or 1 at the time of failure
A similar error can occur when replacing 3.

(5) When the wiring from the changeover switch 14 to one of the control units is cut off, the control modes of the other control unit do not match and the operation of the vehicle body becomes abnormal.

A first object of the present invention is to provide an electronic control device for a hydraulic circuit, which makes it possible to inexpensively replace a control unit for performance improvement.

A second object of the present invention is to avoid the complexity of having to produce many kinds of control units in an electronic control unit for hydraulic circuits only due to the difference in basic data, and at the time of assembly or repair. An object of the present invention is to provide an electronic control device that does not cause a wrong combination of control units and is less likely to cause a mismatch in control states.

[0021]

In order to achieve the above first object, the present invention provides at least one first control unit for controlling a hydraulic circuit and a switching for switching control states of the first control unit. In an electronic control device including a signal generator, a second control unit is provided separately from the first control unit, and the second control unit stores basic data used for control calculation in the first control unit. And first communication means for transmitting basic data to the first control unit based on the signal of the switching signal generator,
Each of the first control units has a second communication means for receiving the basic data and a means for inputting the received basic data and using it for control calculation.

In order to achieve the above first and second objects, the present invention comprises a plurality of first control units for controlling a hydraulic circuit, and a switching signal generator for switching control states of the first control units. In the electronic control device including, a second control unit is provided separately from the first control unit,
The second control unit stores the basic data used for the control calculation in the first control unit, and the first communication for transmitting the basic data to the first control unit based on the signal from the switching signal generator. The first control unit has second communication means for receiving the basic data and means for inputting the received basic data for use in control calculation.

[0023]

In the present invention configured as described above, only the second control unit stores the basic data corresponding to the model and the control state, and the first control unit does not need to store the basic data. It suffices to prepare the same for all models. Therefore, the first control unit can be mass-produced and can be manufactured at low cost. Further, since the second control unit does not have expensive input / output equipment and its accessories, it can be manufactured at low cost. Therefore, the cost of the entire control unit can be reduced, and the control unit for the purpose of performance improvement can be exchanged only by the inexpensive second control unit, and the control unit can be exchanged inexpensively.

In the present invention, the basic data corresponding to the model and the control state is stored only in the second control unit, and the first control unit does not need to store the basic data. All you need is something to prepare. Therefore, the production management of the control unit is facilitated. Next, the first control unit is common to all models with respect to the second control unit that stores the basic data, and an error in combination can be prevented. Further, even when the wiring from the changeover switch to the second control unit is broken, the control modes of both control units match, so that no abnormal operation occurs in the hydraulic circuit.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the overall configuration of the electronic control unit of this embodiment. This electronic control unit includes a hydraulic pump 1, a hydraulic actuator 2 driven by the hydraulic oil discharged from the hydraulic pump 1, a hydraulic oil connected between the hydraulic pump 1 and the hydraulic actuator 2, and supplied to the hydraulic actuator 2. The control valve 3 for controlling the flow rate of the control unit 3, the control unit 7, the control unit 10, the control unit 11, and the changeover switch 14.

The control unit 11 is a control unit for storing basic data, and performs data communication with other control units 7 and 10.

In the hydraulic pump 1, signals from the pressure detector 5 and the swash plate position detector 6 are transmitted to the control unit 7, and the control unit 7 controls the position of the swash plate 1a through the swash plate position control device 8 by the signals. The displacement volume, that is, the discharge flow rate is controlled.

The control valve 3 receives a signal from the control unit 10 by the operating lever 4 and its opening is controlled by the solenoid valves 3L and 3R to control the direction and flow rate of the pressure oil to the actuator 2 or the tank 9. ..

The changeover switch 14 instructs the control unit 11 to change the control state, for example, the control in the normal mode or the control in the fine operation mode.

The structure of the control unit 7 is shown in FIG. The control unit 7 inputs the pressure signal pd of the pressure detector 5 and the swash plate position signal θ from the swash plate detector 6 and converts it into a digital signal, and a central processing unit (CPU).
21a and a read-only memory (ROM) 22a for storing a control procedure program and basic data necessary for control
A random access memory (RAM) 23a for temporarily storing a numerical value during calculation, an output interface (I / O) 24a, an amplifier 25 for outputting a swash plate drive signal to the swash plate control device 8, and a control Units 10, 11 and C
It is composed of a serial interface (SI / O) 27a that performs data communication according to a PU command.

The structure of the control unit 10 is shown in FIG. In the figure, the same parts as the control unit 7 are indicated by the same numbers as in FIG. The operation signal X of the operation lever 4 input to the A / D converter 20b is converted into a digital signal. D / A converter 2
6b reconverts the digital signal into an analog signal, and these analog signals are amplified by the amplifiers 28L and 28R and output to the solenoid valves 3L and 3R. The serial interface (SI / O) 27b communicates data with other control units 7 and 11 according to a command from the CPU.

The structure of the control unit 11 is shown in FIG. C
The PU 21c, ROM 22c, and RAM 23c are the same as the other control units 7 and 10. The serial interface (SI / O) 27c is connected to the other control units 7, 10 and C.
Data is communicated according to a PU command. The digital input interface (D / I) 29c inputs the switch signal Sw of the changeover switch 14.

Serial interface (SI / O) 2
An example of the communication method using 7c is illustrated in FIG. The figure shows communication from the control unit 11 to the control unit 7. The SI / O 27c of the control unit 11 is a CPU
The parallel 1 data sent from 21c is made into time series data bit by bit, and S of the control unit 7 of the communication destination
Communicate to I / O 27a. The SI / O 27a receiving the serial data converts the data received in time series bit by bit into parallel 1 data again. The CPU 21a of the control unit 7 is watching the state of the SI / O 27a, and reads parallel data when it is input. By repeating the above operation, a plurality of data can be communicated. These SI / Os can be easily obtained as commercial LSIs.

The control procedure stored in the ROMs 22a to 22c of each control unit will be described with reference to FIGS.

The control procedure of the control unit 11 is shown in FIG. First, in step 300, the switch signal Sw of the changeover switch 14 is read by the digital input interface (D / I) 29c and it is determined whether the state of Sw has changed. If it has not changed, return to the beginning and repeat this.
When it is determined in step 300 that Sw has changed, step 310
Go to In step 310, the status of Sw is determined. If Sw is ON, it is determined that the control is in the normal mode, and the process proceeds to step 320. In step 320, the basic data Tr in the normal mode is communicated to the control unit 7 via the I / O 27c. Next, in step 330, the same SI / O 27
The basic data Ky, Xo in the normal mode is communicated to the control unit 10 via c. At this time, Tr, Ky and Xo are a set and correspond to a specific model and the control mode at that time.

FIG. 7 shows details of the control procedure 320 of the control unit 11 shown in FIG. In step 321, the Tr data is communicated to the control unit 7 via the serial interface (SI / O) 27c. The structure of the communication data at this time is shown in FIG. At this time, as shown in FIG. 8A, a start code, which is the beginning of the data, and a destination address (in this case, the control unit 7's address) for identifying that the control unit receiving the data is the transmission to itself. No.), Tr data, and an end code indicating the end of the data are transmitted as a set of data. That is, the CPU 21c shown in FIG. 5 and the serial interface (SI /
O) 27c and serial interface (SI / O)
27a, the communication procedure with the CPU 21a is performed four times including a start code, a destination address, Tr data, and an end code, and then transmitted. Next, in step 322, it is determined whether a response from the control unit 7 has been received. When the control unit 7 receives data from the control unit 11 as will be described later, the control unit 7 returns a response thereto. As shown in FIG. 8B, this response data is a set of data including a start code, a source address indicating which control unit the response is from, a response code, and an end code. At this time, the communication procedure shown in FIG. 5 is reversed and performed four times to receive a set of data.

When it is confirmed in step 322 that the response from the control unit 7 is received, the process proceeds to step 330, and the data Ky and Xo are communicated to the control unit 10. This procedure is similar to that shown in procedure 320. However, the data transmitted from the control unit 11 to the control unit 10 is as shown in FIG. 8C, and the destination address is the control unit 10 and two data of Ky and Xo are transmitted. It becomes a set of data. The response data from the control unit 10 is shown in FIG. 8 except that the source address is the control unit 10 as shown in FIG.
It has the same configuration as (a). When the procedure 330 is completed, the procedure returns to the first procedure 300.

In step 310, the switch signal Sw is O
If it is FF, it is determined that the control is in the fine operation mode, and the process proceeds to step 340. In step 340, the basic data Tr in the fine operation mode is transferred to the serial interface (SI /
O) Communicate to the control unit 7 via 27c. The communication method is the same as the procedure 320 described above. Next, in step 350, the basic data Ky in the fine operation mode is set.
, Xo to serial interface (SI / O) 27
Communicate to the control unit 10 via c. When the procedure 350 ends, the procedure returns to the first procedure 300.

As described above, the control unit 11 performs the procedure 3
00 to 350 are constantly repeated.

The control procedure of the control unit 7 is shown in FIG.
The difference from the control procedure of the control unit 12 shown in FIG.
0,140 is added. In step 130, it is determined whether or not there is communication from the control unit 11 via the serial interface (SI / O) 27a. If there is no communication, the process moves to step 100 and normal control is continued.
If it is determined in step 130 that communication has been performed, the process proceeds to step 140. In step 140, the serial interface (S
The target absorption torque Tr of the hydraulic pump, which is the basic data used for the control calculation, is read from the control unit 11 via the I / O) 27a and stored in the RAM 23a. This procedure 1
Details of 40 are shown in FIG. First, in step 141, FIG.
Among the data shown in (a), the destination address is
That is, it is determined whether or not it is the control unit 7. When it is determined that the address is not the self, the procedure moves to step 100 and waits for the communication from the control unit 11 again. When it is determined that the address is itself, the procedure proceeds to step 142. Step 14
In 2, the Tr data shown in FIG. 8A is stored in the RAM 23a. Next, the procedure moves to step 143, the response shown in FIG. 8B is transmitted to the control unit 11, and the procedure moves to step 100 to start normal control. In the next step 110, the target tilt angle θr is calculated using Tr stored in the RAM 23a.

The control procedure of the control unit 10 is shown in FIG. Here, the difference from the control procedure of the control unit 13 shown in FIG. 16 is that the procedures 201 and 202 are eliminated first and the procedures 230 and 240 are added as in the case of the control unit 7. In step 230, it is determined whether there is communication from the control unit 11 via the serial interface (SI / O) 27b. If there is no communication, the procedure moves to step 200 and continues normal control. If it is determined in step 230 that there is communication, the process proceeds to step 240. Step 2
40 for serial interface (SI / O) 27b
The calculation coefficient Ky and the dead zone value Xo, which are the basic data used for the control calculation, are read from the control unit 11 via the memory and stored in the RAM 23b. This procedure is similar to that shown in FIG. 10, and the received data is as shown in FIG. 8C, the stored data is Ky, Xo, and the response to the control unit 11 is shown in FIG. 8 (d) is the only difference. Then, in step 210, the valve operation amounts Y1 and Y2 are calculated using Ky and Xo stored in the RAM 23b.

In the above, the control units 7 and 10 are
Since different data is not required for each model, it is possible to use data common to all models. Therefore, the control units 7 and 10 can be mass-produced and can be manufactured at low cost. Further, since the control unit 11 does not include expensive input / output equipment and equipment attached thereto,
It can be manufactured at low cost.

Therefore, according to this embodiment, it is possible to reduce the cost for the entire control units 7, 10, 11. Further, when replacing the control unit to improve performance, it is sufficient to replace only the inexpensive control unit 11,
Since it is not necessary to replace the control units 7 and 10 having an expensive input / output mechanism, the control units can be replaced at low cost. It should be noted that these effects are obtained when one control unit is used.
That is, the same can be obtained when only the control unit 7 or 10 is used.

Further, according to this embodiment, the basic data corresponding to the model and the control state is stored only in the control unit 11, and the control units 7 and 10 do not need to store the basic data, and are common to all models. Since it suffices to prepare these, it is possible to avoid the complexity of producing many types of these two control units for each model, and it becomes easy to manage the production of the control units. Next, in the production and assembly of a certain model, the control units 7 and 10 are common to all the models, whereas the control unit 11 that stores the basic data peculiar to the model is different from the control unit of this specific model. It is possible to prevent an error in which 7 and 10 are combined. Further, the control states of the control unit 7 and the control unit 10 are unlikely to be inconsistent.

In the above embodiments, the SI / O function in the basic data communication procedure does not restrict the present invention, and an LSI used for a LAN or the like or a method of communicating with a parallel signal is used. Other means are also acceptable. The structure of the communication data is not limited to that shown in this embodiment, and the start code and the end code may be omitted as a fixed data length, or all the data may be converted into character codes for communication between the control units. Any configuration may be used as long as it matches. Although the hydraulic pump and the control unit of the control valve are shown in the present embodiment, the present invention can be applied to other control units that can be considered as a construction machine, such as for an engine and a monitor display. Although a manually operated switch is shown for switching the control mode, other switching signals such as signals from other control units may be used.

[0046]

According to the present invention, it is sufficient to replace only the inexpensive second control unit when replacing the control unit for performance improvement, so that the control unit can be replaced at a low cost. Further, since the first control unit is common to all models, mass production is possible, so that the cost of the entire control unit can be reduced.

Further, according to the present invention, since the plurality of first control units need only be common to all models, production control of the control units can be easily performed. In addition, an error in the combination of the control units is less likely to occur during assembly or repair, and the reliability can be improved. Further, the control states of the control units are unlikely to be inconsistent.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electronic control device that is an embodiment of the present invention.

FIG. 2 is a configuration diagram of a control unit.

FIG. 3 is a configuration diagram of a control unit.

FIG. 4 is a configuration diagram of a control unit.

FIG. 5 is a diagram showing an example of a communication method using a serial interface.

FIG. 6 is a flowchart showing a control procedure stored in a ROM of a control unit.

FIG. 7 is a flowchart showing details of a control procedure.

FIG. 8 is a diagram showing a structure of communication data in a communication method.

FIG. 9 is a flowchart showing a control procedure stored in a ROM of a control unit.

FIG. 10 is a flowchart showing details of a control procedure.

FIG. 11 is a flowchart showing a control procedure stored in a ROM of a control unit.

FIG. 12 is an overall configuration diagram of a conventional hydraulic circuit electronic control device.

FIG. 13 is a configuration diagram of a control unit.

FIG. 14 is a configuration diagram of a control unit.

FIG. 15 is a flowchart showing a control procedure stored in a ROM of a control unit.

FIG. 16 is a flowchart showing a control procedure stored in a ROM of a control unit.

[Explanation of symbols]

 7 Control Unit 10 Control Unit 11 Control Unit 21a-e Central Processing Unit (CPU) 22a-e Read Only Memory (ROM) 23a-e Random Access Memory (RAM) 27a-c Serial Interface (SI / O)

Claims (2)

[Claims] 1. An electronic control device comprising at least one first control unit for controlling a hydraulic circuit, and a switching signal generator for switching a control state of the first control unit, wherein the first control unit is provided. A second control unit is provided separately from the first control unit, and the second control unit stores the basic data used for the control calculation in the first control unit and the basic data based on the signal from the switching signal generator. 1
A first communication means for transmitting to the control unit of
Each of the control units has a second communication unit for receiving the basic data and a unit for inputting the received basic data and using it for control calculation. 2. An electronic control device comprising a plurality of first control units for controlling a hydraulic circuit and a switching signal generator for switching control states of the first control unit, wherein the first control unit is A second control unit is provided separately,
The second control unit stores the basic data used for the control calculation in the first control unit, and the first communication for transmitting the basic data to the first control unit based on the signal from the switching signal generator. And a first control unit each having second communication means for receiving the basic data and means for inputting the received basic data and using it for control calculation. Electronic control unit.