JP2008127957A - Controller for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a working machine enabling an operator to easily obtain a satisfactory feeling of operation. <P>SOLUTION: This controller for the working machine is provided with an operation lever 30 operated by the operator to drive actuators 9-11 mounted on the working machine, a grip sensor 32 for detecting grip gp of the operator gripping the operation lever 30, and a control means 20 for controlling outputs of the actuators 9-11 for amount of operation st of the operation lever 30 in accordance with magnitude of grip gp detected by the grip sensor 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for controlling the output of an actuator mounted on a work machine.

In hydraulic excavators, hydraulic cylinders (actuators) for driving arms, booms, and buckets are generally supplied with pressure oil from a hydraulic pump via a control valve (direction switching valve) in accordance with the operation of an operation lever. Is supposed to work.
The outputs of these actuators are set according to the operation amount of the operation lever.

Here, in particular, in an electronic pilot hydraulic excavator that reads the operation amount of the operation lever with a controller and electrically controls the control valve, the operational feeling (correlation between the operation amount of the operation lever and the output of the actuator) A switching function may be provided.
Work with a hydraulic excavator includes excavation work and water leveling work to level the ground flat, but during normal work such as excavation work, it is preferable to operate the actuator at a relatively high speed. However, during the work, it is preferable to perform the fine manipulation work by operating the actuator at a slower speed than in the normal work.

  The operator can switch the operation feeling to operate the actuator with a large output by operating the operation lever slightly and move the operation area of the operation lever at a high speed. Even if it is operated, the actuator can be operated with a small output, and most of the operating area of the operating lever can be moved at a low speed, so that it is possible to work with a good operational feeling suitable for the working form. .

The switching of the operation feeling is performed by the operator selecting an operation gain. For example, as described in Patent Literature 1, an operation gain changeover switch (shown as a work mode changeover switch in Patent Literature 1) is usually installed in the cab, and an operator operates the operation gain changeover switch. Then, the operation gain is selected, and the controller multiplies the operation amount of the operation lever by the selected operation gain, and controls the output of the actuator according to the multiplication result.
Japanese Patent Laid-Open No. 11-303759

  However, in the case of the technique described in Patent Document 1, in order to switch the operation feeling, the operator must once stop the operation and release the hand from the operation lever to operate the operation gain switching switch. Further, in order to obtain an optimum feeling of operation, the operation gain changeover switch must be operated each time according to work. Therefore, switching of the operational feeling by the operation gain switching switch may cause a deterioration in work efficiency or a burden on the operator.

  The present invention has been devised in view of such problems, and an object of the present invention is to provide a control device for a work machine that allows an operator to easily obtain a good operational feeling.

  In order to achieve the above object, a control device for a work machine according to the present invention detects an operation lever operated by an operator to drive an actuator mounted on the work machine, and a gripping force of an operator who holds the operation lever. A gripping force sensor and control means for controlling the output of the actuator with respect to the operation amount of the operation lever according to the magnitude of the gripping force detected by the gripping force sensor are provided.

  Further, the hydraulic tank for storing pressure oil, a hydraulic pump for supplying pressure oil from the hydraulic tank to the actuator, and a hydraulic circuit for connecting the actuator and the hydraulic pump are interposed in the actuator. A part of the pressure oil supplied from the hydraulic pump to the actuator is interposed between a control valve for controlling the flow rate of the supplied pressure oil and a hydraulic circuit connecting the actuator and the hydraulic pump. A relief valve is provided to return to the tank.

The control means may control the output of the actuator by controlling the control valve.
The control means may control the output of the actuator by controlling the hydraulic output of the hydraulic pump.
The control means may control the output of the actuator by controlling the relief pressure of the relief valve.

  Further, when the magnitude of the gripping force detected by the gripping force sensor is zero, the control means may control the engine to be in an idling state.

  According to the control device for a work machine of the present invention, the output of the actuator with respect to the operation amount of the operation lever, that is, the operation feeling is controlled according to the magnitude of the gripping force detected by the gripping force sensor. Thus, it is possible to switch the feeling of operation satisfactorily by a simple operation of changing the gripping force to grip the operation lever without operating the switch. In other words, the operator normally grips the operating lever strongly when he wants to move the actuator quickly, and conversely, when he wants to move the actuator slowly and perform fine operations, he naturally grips the operating lever weakly. is there. Therefore, the operator can obtain a good operational feeling by controlling the operational feeling using the gripping force correlated with the output of the desired actuator.

  Further, if the control means controls the engine to be in an idling state when the gripping force is zero, fuel efficiency can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
1 to 6 each show a control device for a work machine according to a first embodiment of the present invention, FIG. 1 is a schematic diagram showing the overall configuration, and FIG. 2 is a block diagram for explaining control contents in the controller. 3 is a gain conversion table stored in the controller, FIG. 4 is a mode setting table stored in the controller, FIG. 5 is an operation feeling setting table stored in the controller, and FIG. 6 is a control device for the work machine. It is a perspective view which shows the whole image of the hydraulic shovel which has this.

<Configuration>
Here, a hydraulic excavator as a typical example of a work machine will be described.
As shown in FIG. 6, the excavator 1 has a lower traveling body 2, an upper revolving body (airframe) 3 that is pivotably coupled on the lower traveling body 2, and extends forward from the upper revolving body 3. And the working device 4 attached to the head.

A cab 5 for an operator to board is disposed on the left side of the front part of the upper swing body 3.
The working device 4 includes a boom 6, an arm 7, and a bucket 8. The boom 6 is driven by a boom hydraulic cylinder (actuator) 9, and the arm 7 is driven by an arm hydraulic cylinder (actuator) 10. The bucket 8 is driven by a bucket hydraulic cylinder (actuator) 11.

  As shown in FIG. 1, these actuators 9 to 11 are supplied with pressure oil discharged from a hydraulic pump 12 driven by an engine (prime mover) and extend and contract. A control valve 13 for controlling the direction and flow rate of the pressure oil supplied to the actuators 9 to 11 is interposed on a hydraulic circuit connecting the actuators 9 to 11 and the hydraulic pump 12. The opening degree of the control valve 13 is controlled by a controller (control means) 20 described later.

In FIG. 1, for convenience, the boom hydraulic cylinder 9, the arm hydraulic cylinder 10, and the bucket hydraulic cylinder 11, which are independent actuators, are collectively illustrated as one actuator. Actually, these actuators 9 to 11 are connected to the control valve 13 in parallel, for example.
The cab 5 includes an operator seat for an operator to sit on and an operation lever 30 disposed on the side of the operator seat for operating the work device 4.

The operation lever 30 is a so-called electric lever type operation input device, and is provided with a displacement sensor (operation amount sensor) 31 such as a potentiometer for detecting the operation amount st. The operation amount st detected by the displacement sensor 31 is input to the controller 20 as an electrical signal (operation amount signal).
Further, the operation lever 30 is provided with a pressure-sensitive sensor (gripping force sensor) 32 that senses a gripping force gp for the operator to grip the operating lever 30. Specifically, a sheet-type pressure sensor 32 is wound around the surface of the grip portion of the operation lever 30. The magnitude of the grip force gp sensed by the pressure sensor 32 is input to the controller 20 as an electrical signal (grip force signal).

  Although one operating lever 30 is illustrated in FIG. 1, a pair of left and right operating levers 30 are actually provided in the cab 5. Each of the pair of operation levers 30 is tilted in the front-rear direction and the left-right direction. For example, the tilting operation in the front-rear direction of the right operation lever 30 activates the boom hydraulic cylinder 9 and the right operation lever. The left / right tilting operation 30 operates the bucket hydraulic cylinder 11, and the left / right tilting operation of the left operation lever 30 operates the arm hydraulic cylinder 10.

  The controller 20 is a control device that controls the outputs of the actuators 9 to 11 with respect to the operation amount st of the operation lever 30 in accordance with the magnitude of the gripping force gp of the operation lever 30. As shown, the storage unit 21, the first calculation unit 22, the second calculation unit 23, the third calculation unit 24, and the control unit 25 are included. Here, in this embodiment, the outputs of the actuators 9 to 11 are performed by controlling the control valve 13.

The storage unit 21 stores a preset gain conversion table, a mode setting table, and an operation feeling setting table.
The gain conversion table is a table that defines the relationship between the gripping force gp and the operation gain G, as shown in FIG. Here, the operation gain G is a coefficient used for conversion from the operation amount st of the operation lever 30 to the outputs of the actuators 9 to 11.

In the gain conversion table, it is specified that the operation gain G increases in a substantially step shape as the gripping force gp increases.
More specifically, when the gripping force gp is 0 or more and less than a predetermined minute value (first predetermined value) a ₁ , the operation gain G is set to −10.0 (grip strength gp; 0 to a ₁ , operation Gain G; -10.0). When grip gp is smaller than the second predetermined value a ₂ is greater than the first predetermined value a ₁ in the first predetermined value a ₁ or more, the operation gain G is set to -1.0 (grip strength gp; a ₁ ~ a _2, the operation gain G; -1.0). When grip gp is less than the second predetermined value a ₂ or more at a second predetermined value a ₂ third predetermined value a ₃ is greater than the operating gain G -1.0 with increasing grip strength gp to 0.0 (Grip strength gp; a _{2 to} a ₃ , operation gain G; −1.0 to 0.0).

When grip gp is larger than a fourth predetermined value a ₄ than the third predetermined value a ₃ by the third predetermined value a ₃ or more, the operation gain G is set to 0.0 (grip strength gp; a ₃ ~a ₄ , operation gain G; 0.0). When grip gp is less than a fifth predetermined value a ₅ greater than the fourth predetermined value a ₄ in the fourth predetermined value a ₄ or more, the operation gain G and 0.0 with increasing grip strength gp to +1.0 It is set to increase linearly (grip strength gp; a _{4 to} a ₅ , operation gain G; 0.0 to +1.0). When grip gp is the fifth predetermined value a ₅ or more, the operation gain G is set to +1.0 (grip strength gp; a ₅ to ¶, operating gain G; +1.0).

  As shown in FIG. 4, the mode setting table is a table for selecting an operation mode in accordance with the operation gain G, and has three operation modes: a normal mode, a slow mode, and a quick mode. Yes. If the operation gain G is larger than 0.0 (G> 0.0), the quick mode is selected. If the operation gain G is 0.0 (G = 0.0), the normal mode is selected. If the operation gain G is −1.0 or more and less than 0.0 (−1.0 ≦ G <0.0), the slow mode is selected. When the operation gain G is -10.0 (G = -10.0), the operation mode is not selected and the operation lever 20 is set not to move.

As shown in FIG. 5, the operation feeling setting table is a table that defines the correlation between the operation amount st of the operation lever 30 and the outputs (output commands) op of the actuators 9 to 11 for each operation mode.
In the normal mode, the operation amount st of the operation lever 30 and the outputs op of the actuators 9 to 11 are set to have a linear relationship. That is, the operation amount st and the output op are proportional, and the output op increases linearly as the operation amount st increases. When the operation amount st reaches 100% (maximum value) (that is, when the operation lever 30 is tilted to the limit), the output op is defined to be 100% (maximum output). Yes. In FIG. 5, the correlation in the normal mode is shown as a straight line passing through the origin and the point M.

  In the slow mode, as in the normal mode, the output op is set to 100% when the operation amount st is operated 100%. However, when the operation amount st is relatively small, the output op is relatively small. Only when the operation amount st approaches 100%, the operation amount st increases greatly, and the output op rises slowly with respect to the operation amount st. That is, in the slow mode, compared with the normal mode in which the standard operational feeling is set, in the region where the operation amount st of the operation lever 30 is relatively small, the actuators 9 to 11 have the variation of the operation amount st. The output op is set so as to provide a feeling of operation that responds slowly. In FIG. 5, a graph indicating the correlation between the operation amount st and the output op that gives the most relaxed operation feeling is illustrated as “most slow”.

  Even in the quick mode, as in the normal mode, the output op is set to be 100% when the operation amount st is operated 100%, but the output op is large since the operation amount st is relatively small. It is going to rise. That is, in the quick mode, in the region where the operation amount st is relatively small, the output of the actuators 9 to 11 is set so as to respond more sensitively to the fluctuation of the operation amount st of the operation lever 30 than in the normal mode. Has been. In FIG. 5, a graph showing the correlation between the operation amount st and the output op that gives the most responsive operation feeling is illustrated as “quick”.

  That is, in the slow mode and the quick mode, the output op changes in a curve with respect to the change in the operation amount st. On the operation feeling setting table, the quick mode curve and the slow mode curve are It is symmetrical about the straight line of normal mode. Although the graph is omitted in FIG. 5, the quick mode curve is innumerable according to the value of the operation gain G in the region surrounded by the normal mode straight line and the “most quick” curve. It is set up. The same applies to the slow mode curve. The slow mode curve is infinitely set in accordance with the value of the operation gain G in the area surrounded by the normal mode straight line and the “most slow” curve. It has become so. All of these curves are set as curves passing through the origin and the point M. In other words, the degree of bending with the normal mode straight line of the quick mode curve and the slow mode curve as the reference line changes according to the value of the operation gain G.

As shown in FIG. 2, the first calculation unit 22 calculates an operation gain G using a gain conversion table stored in the storage unit 21 based on the grip strength gp obtained from the pressure sensor 32. . The operation gain G calculated here is input to the second calculation unit 23 and the third calculation unit 24.
The second calculation unit 23 selects an operation mode using the mode setting table stored in the storage unit 21 based on the operation gain G calculated by the first calculation unit 22. For example, as described above, the normal mode is selected when the operation gain G is 0.0 (G = 0.0), and the quick mode is selected when the operation gain G is greater than 0 (G> 0.0). When the operation gain G is less than 0 and −1.0 or more (−1.0 ≦ G <0.0), the slow mode is selected, and the operation gain G is −10.0 (G = −10.0). Sometimes, the operation mode is not selected and the operation lever 30 is prevented from moving. The operation mode selected here is input to the third calculation unit 24.

  The third calculation unit 24 uses the operation feeling setting table stored in the storage unit 21 based on the operation mode selected by the second calculation unit 23 to output the outputs op of the actuators 9 to 11 according to the operation amount st. It is to calculate. When the operation mode is the slow mode or the quick mode, the operation gain G calculated by the first calculation unit 22 is used again in order to determine the degree of curvature of the mode curve on the operation feeling setting table. It has become.

  For example, when the operation gain G is 0.0 (G = 0.0), the operation feeling setting table is set to a straight line in the normal mode shown in FIG. When the operation gain G is +1.0 (G = + 1.0), the operation feeling setting table is set to the “quickest” curve. When the operation gain G is greater than 0.0 and less than +1.0 (0.0 <G <+1.0), a quick mode curve corresponding to the gain value is set, and the closer the gain value is to 0.0. The quick mode curve has a shape close to a normal mode straight line, and the closer the gain value is to +1.0, the quick mode curve has a shape closer to the “quickest” curve.

  On the other hand, when the operation gain G is −1.0 (G = −1.0), the operation feeling setting table is set to the “slowest” curve. When the operation gain G is greater than −1.0 and less than 0.0 (−1.0 <G <0.0), the slow mode curve is the straight line of the normal mode as the gain value is closer to 0.0. The curve of the slow mode is set so as to be closer to the “slowest” curve as the gain value is closer to +1.0.

  The control unit 25 controls the pilot pressure acting on the control valve 13 according to the output op calculated by the third calculation unit 24 and adjusts the position of the spool of the control valve 13. If the position of the spool of the control valve 13 is adjusted, the opening of the control valve 13 is adjusted, the flow rate of the pressure oil supplied to the actuators 9 to 11 is controlled, and the output (operation speed) of the actuators 9 to 11 is adjusted. Can be changed.

<Action and effect>
The work machine control device according to the first embodiment of the present invention is configured as described above, and thus has the following operations and effects.
The operator operates the operating device 4 by operating the operating lever 30. The operation amount st of the operating lever 30 is detected by the displacement sensor 31 and input to the controller 20, and the operator operates the operating lever 30. The gripping force gp to be gripped is detected by the pressure sensor 32 and input to the controller 20.

In the controller 20, the first calculation unit 22 calculates the value of the operation gain G based on the gain conversion table stored in the storage unit 21 according to the magnitude of the input gripping force gp. For example, as in the case indicated by the black circle K in FIG. 3, when the gripping force gp is a value a _K that is larger than the fourth predetermined value a _{4 and} smaller than the fifth predetermined value a ₅ , the gain value b _K of the operation gain G is Calculated.

Next, in the second calculation unit 23, the operation mode is selected according to the value of the operation gain G calculated by the first calculation unit 22. For example, when the operation gain G in the above case is a positive value b _K , the quick mode is selected.
Then, in the third calculation unit 24, based on the operation mode selected by the second calculation unit 23, the outputs op of the actuators 9 to 11 corresponding to the input operation amount st are calculated. For example, when the quick mode of the above case is selected, a quick mode curve having a degree of curvature corresponding to the gain value b _n of the operation gain G is set, and the operation amount st on the quick mode curve is set. The outputs op of the actuators 9 to 11 are calculated.

Then, in the control unit 25, the control valve 13 is controlled according to the output op calculated by the third calculation unit 24. For example, if the output is 80%, the position of the spool is controlled so that the opening degree of the control valve 13 is slightly throttled compared to when it is fully opened, and the flow rate of the pressure oil to the actuators 9 to 11 is controlled.
As described above, the actuators 9 to 11 controlled by the controller 20 have a relatively low operating speed if the pressure oil flow rate is relatively small, and the operating speed increases as the pressure oil flow rate increases.

Accordingly, the operator changes the gain value of the operation gain G while continuing the operation with a simple operation of changing the gripping force gp for gripping the operation lever 30 without releasing the hand from the operation lever 30, and the pressure sensor 32 It is possible to switch to a good operational feeling according to the magnitude of the sensed grip strength.
That is, when the operation lever 30 is gripped relatively weakly, the opening degree of the control valve 13 gradually increases when the operation amount st is small, and the opening degree of the control valve 13 suddenly increases when the operation amount st increases to some extent. The mode is automatically switched to the ascending slow mode, and an operation with excellent fine operability and high fuel efficiency can be performed.

On the contrary, when the operation lever 30 is gripped relatively strongly, the opening degree of the control valve 13 rapidly increases when the operation amount st is small, and thereafter, the opening degree of the control valve 13 gradually increases. It is possible to perform an operation with high agility and high output.
Furthermore, generally, when an operator wants to move the actuators 9 to 11 quickly, a natural force is applied, and conversely, when the actuators 9 to 11 are moved slowly to perform a fine operation, the force is released. There is a nature. Utilizing such properties, the controller 20 uses the gripping force gp correlated with the desired output op of the actuators 9 to 11 to control the operational feeling, so that the operator can intuitively feel the optimal operational feeling. Can be obtained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8 show a control device for a work machine according to a second embodiment of the present invention. FIG. 7 is a block diagram for explaining the control contents of the controller, and FIG. 8 is a hydraulic pressure stored in the controller. It is an output setting table.

<Configuration>
In the second embodiment, the control content of the controller 40 is different from the control content of the controller 20 of the first embodiment. That is, in the first embodiment, the controller 20 uses the operation gain G calculated according to the gripping force gp to control the spool position of the control valve 13 with respect to the lever operation amount st, and outputs the outputs of the actuators 9 to 11. In the second embodiment, the controller 40 controls the hydraulic pressure output (maximum pressure) of the hydraulic pump 12 using the operation gain G calculated according to the gripping force gp, and outputs the outputs of the actuators 9 to 11. It comes to control. The spool position of the control valve 13 with respect to the lever operation amount st is simply controlled as in the conventional case, that is, as in the normal mode of the first embodiment.

Here, only the controller 40 which is the difference between the first embodiment and the second embodiment will be described, and the description of the other parts will be omitted.
As shown in FIG. 7, the controller 40 includes a storage unit 41, a first calculation unit 42, a second calculation unit 43, and a control unit 45.
As shown in FIG. 8, the storage unit 41 stores a hydraulic output setting table that defines the relationship between the operation gain G and the hydraulic output of the hydraulic pump 12, and a gain conversion table shown in FIG.

  The hydraulic output setting table will be described in detail. In this table, as shown in FIG. 8, when the operation gain G is 0.0 (G = 0.0), the hydraulic output is set to a standard value of 100%. When the operation gain G is between 0.0 and +1.0 (0.0 <G <+1.0), the hydraulic output increases linearly from 100% to 120% as the gain value of the operation gain G increases. When the operation gain G is +1.0 (G = + 1.0), the hydraulic pressure output is set to 120%. When the operation gain G is between 0.0 and −1.0 (−1.0 <G <0.0), the hydraulic output increases from 100% to 80% as the gain value of the operation gain G decreases. When the operation gain G is −1.0 (G = −1.0), the hydraulic pressure output is set to 80%. Furthermore, when the operation gain G is -10.0 (G = -10.0), the hydraulic pressure output is set to 20%.

Since the gain conversion table is the same as that described in the first embodiment, description thereof is omitted.
The first calculation unit 42 is the same as the first calculation unit 22 of the first embodiment, and is stored in the storage unit 41 based on the grip strength obtained from the pressure sensor 32 as shown in FIG. The operation gain G is calculated using the gain conversion table. The operation gain G calculated here is input to the second calculation unit 43.

Based on the operation gain G calculated by the first calculation unit 42, the second calculation unit 43 calculates a hydraulic pressure output using a hydraulic pressure table stored in the storage unit 41. The hydraulic pressure output calculated here is input to the control unit 45.
The control unit 45 controls the displacement volume of the hydraulic pump 12 (in the case of a swash plate pump, the amount of swash plate tilt) based on the hydraulic output calculated by the second calculation unit 43. If the displacement volume of the hydraulic pump 12 is controlled, the maximum flow rate of the pressure oil supplied to the actuators 9 to 11 changes. Therefore, the actuator corresponding to the operation amount st of the operation lever 30 according to the magnitude of the gripping force gp. The output (operation speed) of 9 to 11 changes.

<Action and effect>
Since the control device for a work machine according to the second embodiment of the present invention is configured as described above, the operator can move the operation lever 30 without releasing the hand from the operation lever 30 as in the first embodiment. The value of the operation gain G can be changed while continuing the operation by a simple operation of changing the gripping force gp to be gripped. The hydraulic output of the hydraulic pump 12 can be controlled by the operation gain G changed according to the gripping force gp, and a good operational feeling can be obtained.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. FIGS. 9 to 11 show a control device for a work machine according to a third embodiment of the present invention, FIG. 9 is a schematic diagram showing the overall configuration, and FIG. 10 is a block diagram for explaining the control contents in the controller. FIG. 11 is a relief pressure setting table stored in the controller.

<Configuration>
In the third embodiment, similarly to the second embodiment, the control content of the controller 50 is different from the control content of the controller 20 of the first embodiment. That is, the controller 50 of the third embodiment controls the set pressure (relief pressure) of the relief valve 15 described later using the operation gain G calculated according to the gripping force gp, and outputs the outputs of the actuators 9 to 11. It comes to control. The spool position of the control valve 13 with respect to the lever operation amount st is simply controlled as in the normal mode of the first embodiment.

Here, only the controller 50 and the hydraulic circuit, which are the differences between the first embodiment and the third embodiment, will be described, and description of other parts will be omitted.
In the third embodiment, as shown in FIG. 9, the hydraulic pump 12, the control valve 13, and the actuators 9 to 11 are provided on the hydraulic circuit, and the inflow pressure of the pressure oil to the actuators 9 to 11 is adjusted. A relief valve 15 for control is interposed on a supply path between the hydraulic pump 12 and the control valve 13.

As illustrated in FIG. 10, the controller 50 includes a storage unit 51, a first calculation unit 52, a second calculation unit 53, and a control unit 55, and an operation gain G according to the magnitude of the gripping force gp of the operation lever 30. And the output of the actuators 9 to 11 is controlled by controlling the relief pressure of the relief valve 15 in accordance with the operation gain G.
The storage unit 51 stores a relief pressure setting table that defines the relationship between the operation gain G and the relief pressure of the relief valve 15 as shown in FIG. 11, and a gain conversion table shown in FIG. In the relief pressure setting table, as shown in FIG. 11, when the operation gain G is larger than 0.0 (G> 0.0), the relief pressure is increased and the operation gain G is -1.0 or more and 0.0 or less ( When -1.0 ≦ G ≦ 0.0), the relief pressure is set as a standard, and when the operation gain G is −10.0 (G = −10.0), the relief pressure is reduced. Specifically, when the operation gain G is greater than 0.0 (G> 0.0), the relief pressure is increased to a value proportional to the magnitude of the operation gain G, and when the operation gain G is −10.0, the relief pressure is increased. The pressure is set to be lowered to an appropriate value.

The first calculation unit 52 is the same as the first calculation unit 22 of the first embodiment, and uses a gain conversion table stored in the storage unit 51 based on the grip strength gp obtained from the pressure sensor 32. Thus, the operation gain G is calculated. The operation gain G calculated here is input to the second calculation unit 53.
Based on the operation gain G calculated by the first calculation unit 52, the second calculation unit 53 calculates a relief pressure using a relief pressure setting table stored in the storage unit 51. The relief pressure calculated here is input to the control unit 55.

  The control unit 55 controls the opening degree of the relief valve 15 based on the relief pressure calculated by the second calculation unit 53, and sets the relief valve 15 out of the pressure oil supplied from the hydraulic pump 12 to the actuators 9 to 11. The flow rate of the pressure oil that returns to the hydraulic tank is controlled. If the relief pressure of the relief valve 15 is controlled, the flow rate of the pressure oil supplied to the actuators 9 to 11 changes. Therefore, the actuators 9 to 11 corresponding to the operation amount of the operation lever 30 according to the magnitude of the gripping force gp. Output (operation speed) will change.

<Action and effect>
Since the control device for a work machine according to the third embodiment of the present invention is configured as described above, the operator can move the operation lever 30 without releasing the hand from the operation lever 30 as in the first embodiment. The value of the operation gain G can be changed while continuing the operation by a simple operation of changing the gripping force gp to be gripped. And the relief pressure of the relief valve 15 is controlled by the operation gain G changed according to the gripping force gp, and a good feeling of operation can be obtained.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention.
For example, in each of the first to third embodiments, only one object such as the control valve 13, the hydraulic pump 12, or the relief valve 12 is controlled using the operation gain G calculated according to the gripping force gp. However, a plurality of objects may be controlled. In other words, all of the spool position of the control valve 13, the hydraulic output of the hydraulic pump 12, and the relief pressure of the relief valve 15 may be controlled using the operation gain G calculated according to the gripping force gp. A combination of the spool position of the control valve 13 and the hydraulic pressure output of the hydraulic pump 12, the spool position of the control valve 13 and the relief pressure of the relief valve 15, the hydraulic output of the hydraulic pump 12 and the relief pressure of the relief valve 15 may be controlled. good.

  Moreover, in the said 1st-3rd embodiment, although the operator's operation feeling by the operation lever 30 was switched using the magnitude | size of the grip strength gp, in such a case, when the magnitude | size of the grip strength is 0, that is, When the operator does not hold the operation lever 30, a function of controlling the engine to an idling state and reducing the engine speed may be provided. In this way, there is an advantage that fuel consumption can be improved.

  Furthermore, in the above-described embodiment, the case where the work machine control device of the present invention is applied to a hydraulic excavator has been described. However, the work machine control device of the present invention can be appropriately modified to other work machines such as a bulldozer and a crane. It is possible to apply.

It is a schematic diagram which shows the whole structure of the control apparatus of the working machine which concerns on 1st Embodiment of this invention. It is a block diagram explaining the control content in the controller of the control apparatus of the working machine which concerns on 1st Embodiment of this invention. It is a gain conversion table memorize | stored in the controller of the control apparatus of the working machine which concerns on 1st Embodiment of this invention. It is a mode setting table memorize | stored in the controller of the control apparatus of the working machine which concerns on 1st Embodiment of this invention. It is the operation feeling setting table memorize | stored in the controller of the control apparatus of the working machine which concerns on 1st Embodiment of this invention. 1 is a perspective view showing an overall image of a hydraulic excavator having a control device for a work machine according to a first embodiment of the present invention. It is a block diagram explaining the control content in the controller of the control apparatus of the working machine which concerns on 2nd Embodiment of this invention. It is a hydraulic output setting table memorize | stored in the controller of the control apparatus of the working machine which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the whole structure of the control apparatus of the working machine which concerns on 3rd Embodiment of this invention. It is a block diagram explaining the control content in the controller of the control apparatus of the working machine which concerns on 3rd Embodiment of this invention. It is a relief pressure setting table memorize | stored in the controller of the control apparatus of the working machine which concerns on 3rd Embodiment of this invention.

Explanation of symbols

1 Excavator (work machine)
2 Lower traveling body 3 Upper swing body 4 Working device 5 Cab 6 Boom 7 Arm 8 Bucket 9 Boom hydraulic cylinder (actuator)
10 Hydraulic cylinder for arm (actuator)
11 Bucket hydraulic cylinder (actuator)
12 Hydraulic pump 13 Control valve 15 Relief valve 20, 40, 50 Controller (control means)
21, 41, 51 Storage unit 22, 42, 52 First operation unit 23, 43, 53 Second operation unit 24 Third operation unit 25, 45, 55 Control unit 30 Operation lever 31 Displacement sensor 32 Pressure sensor (grip force sensor) )
G Operation gain gp Grip strength st Operation amount

Claims (5)

An operation lever operated by an operator to drive an actuator mounted on the work machine;
A grip force sensor for detecting a grip force of an operator gripping the operation lever;
A control device for a work machine, comprising: control means for controlling an output of the actuator with respect to an operation amount of the operation lever in accordance with a magnitude of the grip force detected by the grip force sensor. A hydraulic pump for supplying pressure oil to the actuator;
A control valve which is interposed on a hydraulic circuit connecting the actuator and the hydraulic pump and controls the flow rate of the pressure oil supplied to the actuator;
The control device for a work machine according to claim 1, wherein the control means controls the output of the actuator by controlling the control valve. A hydraulic pump for supplying pressure oil to the actuator;
The control device for a work machine according to claim 1, wherein the control means controls the output of the actuator by controlling the hydraulic output of the hydraulic pump. A hydraulic tank for storing pressure oil;
A hydraulic pump for supplying pressure oil from the hydraulic tank to the actuator;
A relief valve interposed on a hydraulic circuit connecting the actuator and the hydraulic pump and returning a part of the pressure oil supplied from the hydraulic pump to the actuator to the hydraulic tank;
The control device for a work machine according to claim 1, wherein the control means controls the output of the actuator by controlling a relief pressure of the relief valve. 5. The control device according to claim 1, wherein the control means controls the engine to be in an idling state when the magnitude of the grip force detected by the grip force sensor is zero. The control device of the work machine as described in 1.

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