KR100335363B1 - Excavator control equipment - Google Patents

Abstract

In particular, the present invention relates to a control apparatus for an excavator, and more particularly to a control apparatus for an excavator, which is equipped with a lower traveling body and an upper revolving body and includes a plurality of articulated working devices attached to the upper revolving structure, An apparatus for controlling an excavator having an actuator for driving a device, a swing device and a traveling device, a hydraulic control valve for controlling a flow rate supplied to the actuator, and a sensor for detecting a rotation angle of each working device, A pair of operation devices capable of controlling the three-directional motion in accordance with the operation and outputting an electric signal proportional to an amount deviated from the neutral in each operation direction, a plurality of function selection switches, A switch board for outputting a signal and displaying a selected function at the same time, Receiving a signal from the sensor to the feed a plurality of working device control signal to the hydraulic control valve is characterized by configured by comprising a controller for controlling the flow rate supplied to the actuator to a control device of a joint working device.

Description

Excavator control equipment

The present invention relates to a control apparatus for an excavator, and more particularly, to an intuitive control relation between an organizational apparatus and a work apparatus driven thereby to provide a logical correlation between a movement of the operation apparatus and a movement of the work apparatus, To a control device for an excavator which allows a work device of multiple degrees of freedom to be easily operated.

Generally, an excavator has a working device composed of a plurality of joints, a swing device and a traveling device, and a large number of operating devices such as levers and pedals are required to operate the excavator.

However, since there is little logical correlation between the operation device and the work device, it is difficult for untrained workers to perform operations requiring a high level of operation technology such as flat work, and in order to operate a large number of operation devices to a high degree, Effort was needed.

In addition, even a skilled worker has a disadvantage that the operation efficiency of the worker is reduced due to fatigue and stress easily when operating a large number of operation devices.

In order to overcome the above-mentioned disadvantages, a device (US 4059196, Japanese Unexamined Patent Publication No. 62-33944, Japanese Unexamined Patent Publication No. 5-257551) designed to manufacture an operation fixture by a small model of a working device and to follow its position has been devised, Not only inconvenient, but also the manipulation device was complicated because it had to follow.

In addition, it is also contemplated that an operation device installed on a conventional vertical plane is installed on a horizontal plane so that the operation device and the working device are identical to each other in plane so as to perform an intuitive operation (Japanese Patent Application Publication No. 58-22613, -131066, US5160239, US5424623, EPO361666A1, and Japanese Unexamined Patent Publication No. 4-134570, Japanese Unexamined Patent Publication No. 3-275819), but the safety device at the time of operation was insufficient and the turning operation and the driving operation were not out of the existing frame, there was.

On the other hand, since an operation method is different for each equipment, an invention that can select an operation method according to an operator's preference (Japanese Unexamined Patent Publication No. 5-156665, Japanese Unexamined Patent Application Publication No. 64-31153, Japanese Unexamined Patent Publication No. 4-30034) And only a simple one-to-one correspondence between the operating device and the working device was considered, a great deal of effort was required for skilled operation.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device for an excavator which can freely operate a multi-joint work device, a traveling device and a pivoting device with both hands.

It is another object of the present invention to provide an intuitive control relationship between an operator and a work apparatus, so that the movement of the operation apparatus and the movement of the work apparatus are logically correlated with each other so that an operator can easily operate And to provide a control device for a printing machine that can perform printing.

Yet another object of the present invention is to provide a control apparatus for an excavator which facilitates an operation using a highly skilled operation technique by setting various functions of the equipment so that the operator can select the function appropriately according to the situation It is on.

The above-described object of the present invention is achieved by a working device comprising a plurality of joints, such as a boom attached to a front end of an upper revolving structure turning with respect to a lower traveling body, an arm attached to a front end of the boom, A traveling device for driving left and right tracks of the lower traveling body; a working cylinder as an actuator for driving the traveling devices and the traveling devices; A boom angle detection sensor installed between the boom and the upper revolving body for detecting a relative rotation angle of the boom with respect to the upper revolving body; a hydraulic control valve for regulating the flow rate of the hydraulic fluid supplied to each actuator by a predetermined signal; A rocking angle detection sensor provided between the boom and the arm for detecting a relative rotation angle of the arm with respect to the boom, A control device for an excavator having a bucket angle detection sensor for detecting a relative angle of a bucket, the control device being capable of controlling three-directional motions in response to an operation by an operator, A switch board that is provided with a plurality of function selection switches for outputting a red signal and outputs a predetermined signal according to a function selection and simultaneously displays a selected function; And a controller for receiving a signal from the hydraulic control valve and controlling the flow rate supplied to the actuators by supplying a plurality of work device control signals to the hydraulic control valve. .

According to a preferred aspect 1 of the present invention, the operating device is provided on a vertical plane so as to have the same operating plane as the working plane of the working device, and includes a first operating device for driving the working device in accordance with the operation amount and the operating direction, And a second operating device provided on the horizontal plane for driving the traveling device and the turning device in accordance with the operation amount and the operating direction.

According to a preferred second aspect of the present invention, the first operating device has a first operation direction reciprocating with respect to the first axis, a second operation direction reciprocating with respect to the second axis orthogonal to the first axis, And is operated in a third operating direction rotating about a third axis orthogonal to the plane formed by the axis and the second axis.

According to a preferred aspect 3 of the present invention, the second operating device has a first operating direction reciprocating with respect to the first axis, a second operating direction reciprocating with respect to the second axis orthogonal to the first axis, And a third operating direction that is rotated with respect to a third axis orthogonal to the plane formed by the axis and the second axis, and the operating directions of the three directions are the forward and backward travel of the traveling device, the left and right rotation of the traveling device, Respectively.

According to a preferred aspect 4 of the present invention, there is further provided a turn selection switch provided on a circumferential surface of the second organization apparatus, for outputting a signal for a third operation direction by the second operation apparatus to the controller in an on state Respectively.

According to still another aspect of the present invention, there is further provided a turning sensor installed between the upper revolving body and the lower traveling body and sensing the relative angle of the upper revolving body with respect to the lower traveling body and outputting the sensed relative angle to the controller.

According to a preferred aspect 6 of the present invention, the relative angle of the lower traveling body sensed by the turning sensor to the upper tilting system is 180 degrees, and the forward traveling speed of the lower traveling body due to the first operating direction of the second operating device The backward operation is alternately controlled so that the operator's coordinates always coincide with the forward and rearward operating concepts.

According to a preferred seventh aspect of the present invention, the switch board includes a flat work switch for determining whether to perform a flat work on a curved surface to be worked,

A bucket angle holding switch for determining whether to keep the absolute angle of the bucket constant during a work, an angle setting switch for setting an angle of a flat surface to be worked in the case of a flat work, And a display unit for displaying various information such as an operation state of the equipment and an operation mode.

According to a preferred feature 8 of the present invention, when the manual mode is selected by the mode selection switch, the first operation direction of the first operation device is the operation of the boom, the second operation direction is the operation of the arm, Control the operation of the bucket (manual operation).

According to the preferred feature 9 of the present invention, when the automatic mode is selected by the mode selection switch, the pivot point of the bucket is followed by the direction and the manipulated amount in the first and second operating directions of the first operating device, (Automatic operation) so that the bucket is operated by the direction and the operation amount of the bucket.

According to a preferred feature 10 of the present invention, the control device is provided on the circumferential surface of the first operating device and outputs a predetermined signal to the controller in the direction of the third operating direction of the first operating device and the manipulated variable in the ON state And further comprises a bucket informer switch.

According to a preferred feature 11 of the present invention, when the bucket angle holding switch is selected during the automatic operation, the relative angle of the bucket with the arm is further followed while maintaining the absolute angle of the bucket set by the operator When the bucket is operated at the same time, the bucket is controlled prior to the operation of the operator so that the final angle of the bucket is controlled to be the absolute angle to be followed again.

According to the preferred feature 12 of the present invention, when the flat work switch is selected, the automatic operation is automatically selected, and the relative angle of the upper swing body and the boom, the relative angle of the boom and the arm, and the relative angle of the arm and the bucket are detected The front end of the bucket is followed by the direction and the amount of the operation by the first operation direction and the second operation direction of the first operation device by the automatic operation and simultaneously the bucket is operated by the direction and the operation amount by the third operation direction.

According to a preferred feature 13 of the present invention, when the flat operation switch and the bucket angle maintenance switch are simultaneously selected, the control is performed so that the position of the bucket tip follows the operation amount by the automatic operation of the first operation device and the operation direction, The bucket is controlled in such a manner that the position of the bucket tip does not move and the bucket is controlled prior to the operation of the operator and when there is no operation signal of the bucket, do.

According to a preferred aspect of the present invention, a tracking point, which is provided at a front end of the first operating device and is followed by a predetermined operating direction and a manipulated variable of the first operating device in a state of being connected to the controller, To be operated in a working plane set by the user.

According to a preferred feature 15 of the present invention, when the switch is selected during the flat operation, the tip of the bucket which is followed by the direction and the manipulated variable according to the first operating direction and the second operating direction of the first operating device, And controls it to operate in the working plane having the set constant angle.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic view showing a control device for a turning device and a traveling device of an excavator according to an embodiment of the present invention, FIG. 2 is a schematic view showing a control device for a working device for an excavator according to an embodiment of the present invention And FIG. 3 is a schematic view of FIG. 2.

As shown in Figures 1 and 2, there is a working device 100 mounted on the machine, which comprises a boom 40, which is the first linkage attached to the top of the machine, A linking arm 50 and a bucket 60, which is a working mechanism connected to the arm end, are provided, and this working mechanism may be different for each working device.

Such an excavator is composed of a lower traveling body 79, an upper swing body 70 pivotally coupled to the lower traveling body, and a work which is coupled to the front part of the upper swing body and can be angularly changed by a plurality of joints (100).

The working device 100 is operated in a vertical plane and has a plurality of vertical planes which are the working areas by rotating the pivot point of the boom 40 or the equipment top 70.

The boom 40 is operated by the hydraulic cylinder 41 and moves the work apparatus 100 up and down so that the arm 50 can be moved by the hydraulic cylinder 51 to move the work tool farther or farther away from the equipment, 60 are opened or closed by the hydraulic cylinder 61.

A boom angle detection sensor 46 is provided between the boom 40 and the upper swing body 70 to detect the relative rotation angle of the boom with respect to the upper swing body. A rocket angle detection sensor 56 for detecting the relative rotation angle of the arm and a bucket angle detection sensor 66 for detecting the phase angle of the bucket with respect to the arm are provided between the arm 50 and the bucket 60 .

The flow rates supplied to the working cylinders 41, 51 and 61 are adjusted by the hydraulic pressure control valves 42, 52 and 62 and are controlled by the respective hydraulic motors 74, 84 and 194 in the case of the swing operation and the traveling operation The supplied flow rate is operated by the hydraulic control valves 76, 86 and 196 and the operating devices 20 and 30, the switch board 90 and the controller 10 are installed between the hydraulic control valve and the operator .

The swing motor 74 drives the upper swing body 70 of the equipment. The left traveling motor 84 is responsible for the left traveling of the equipment and the right traveling motor 194 is for the right traveling.

The operating devices 20 and 30 constituted by an electric joystick or the like are respectively provided on the right and left sides of the operator to allow movement in three directions. As shown in FIG. 2, the first operating device 20 provided on one side of the driver's seat is mounted on a horizontal plane and is movable in a vertical direction (X-axis) , A second operating direction (23, 24) reciprocating in a forward and backward direction (Y-axis) orthogonal to the first axis and a first operating direction (21, 22) And a third operating direction (26, 27) rotating about a third axis (Z axis) orthogonal to the plane formed by the two axes.

As shown in FIG. 1, the second operating device 30 provided on the other side of the driver's seat is provided with a front- (33, 34) reciprocating in a first operating direction (31, 32) reciprocating in two axes (Y axis) and a third axis (Z axis) in a lateral direction orthogonal to the second axis , And a third operating direction (36, 37) rotating about a first axis (X axis) orthogonal to the plane formed by the second axis and the third axis.

The above-described first operating device 20 and second operating device 30 generate an electrical signal proportional to an amount deviated from the neutral in each operating direction, and this electrical signal is transmitted to the switch board 90 together with the operation of the switch board 90 Is input to the controller 10 and processed.

The switch board 90 is provided with a plurality of function switches so as to be able to select a program function that has already been programmed, so that the task function is transmitted to the controller 10 according to the selection of the operator, A mode selection switch 91 for converting the operation of the operating device into a manual mode and an automatic mode, and a mode selection switch 91 for use in a case of performing a flat operation on a certain sloped surface A bucket angle holding switch 94 for determining whether to keep the absolute angle of the bucket 60 constant during operation, and a bucket angle holding switch 94 for setting the angle of the flat surface to be worked A switch 93 is provided.

Here, a potentiometer (potentiometer) or an up-down switch or the like is used so that the angle setting switch 95 can set a continuous angle.

Preferably, the first operating device 20 and the second operating device 30 are provided with an output for an undesired third operating direction when operating in the first or second operating direction, The bucket safety switch 28 and the turn safety switch 38 are provided on the circumferential surface of the operating device of the vehicle. That is, only when the bucket safety switch and the turn safety switch are turned on, the operation for the third operation direction of each operation device is outputted.

The controller 10 receives signals from the aforementioned switch board 90 and the operating devices 20 and 30 and signals from the respective joint sensors 46 and 56 and 66 and outputs a plurality of work device control signals to the hydraulic control valve 42 51 and 61 and the motors 74, 84, and 194 in accordance with the control signal transmitted from the controller 10, The flow rate is controlled to move the working device, the turning device and the traveling device to the operator's will.

The control device associated with the working device 100 will be described first with reference to FIG. 2 in the thus configured state.

When the state of the mode selection switch 91 of the switch board is the same, the relationship between the first operating device 20 and the working device 100 is as follows.

In the case of such a manual operation, since the operating surface of the first operating device and the operating surface of the working device are the same vertical plane, it is easy to estimate the logical direct correlation and intuitive control is possible.

On the other hand, when the automatic mode is selected, the controller 10 is used so that the pivot point 63 of the bucket is followed by the direction and the manipulated variable by the combination of the first operating direction and the second operating direction of the first operating device 20 And controls the relative angle of the boom (40) and the arm (50). At this time, the input to the dispenser 10 is the operating direction and the manipulated variable of the first operating device, and the output is the relative angle of the boom joint and the arm joint. Preferably, the relative angles of the respective joints are measured by the joint angle detection sensors 46, 56 and 66 and input to the controller 10, and a resolver separator or encoder is used as the joint angle lead-out sensor .

The bucket 60 can be operated by the third operating direction in this state and the movement of the bucket 60 is determined only by the rotational directions 26 and 27 which are the third operating directions, The signal of the bucket 60 is processed by the controller 10 only when the bucket safety switch 28 is activated. Therefore, the operator must always operate the bucket safety switch 28 while pushing the bucket.

The controller 10 must control the relative angles? ₁ and? ₂ of the boom and the arm in order to match the pivot point 63 of the bucket with the operating direction of the first operating device and the operating ring, As shown in FIG. 3, the angle is defined as (x ₂ , y ₂ ) the position of the bucket with respect to the pivot point 63, the length of the boom I ₁ , the length of the arm I ₂ , If the velocity of the pivot point 63 of the pivot point 63 is V ₂ , it can be divided into a horizontal component V _2X and a vertical component V _2y , which can be calculated as follows.

Also, when the flat direct-connect switch 92 of the switch board 90 is selected, the automatic mode is set to be selected by itself regardless of whether or not the automatic mode is selected. At this time, the controller 10 controls the position of the bucket tip 64 in accordance with the operating direction and the manipulated variable of the first operating device 20 by the operator's organization. That is, the pivot point 63 of the bucket, which has followed the automatic mode operation by the operation amount of the first operating device 20 and the operating direction, while using the entire range without limiting the angle of the bucket 60 to a certain angle, The relative angle (? ₃ ) of the bucket with respect to the arm is controlled so as to follow the leading end 64 to maintain the absolute angle of the already set bucket. At this time, when the bucket 60 is operated by the operation signal in the third operating direction, the bucket is operated and the angle of the final bucket is set again to the absolute angle of the bucket to be followed again.

Preferably, when the flat occupation switch 92 of the switch board 90 is operated in the selected state, the position of the bucket tip 64 is controlled only in a plane having an angle set by the angle setting switch 93 of the switch board 90 The switch 29 is provided at the front end of the first operating device 20. [ At this time, the tracking direction and the tracking speed follow the second operating direction of the first operating device. In this state, if there is a bucket operation signal by the operator in the third operation direction of the first operation device, the bucket is operated by the operation direction and the operation amount.

Further, when the bucket angle holding switch 94 is selected during the flat work, all the above-mentioned operations are controlled so that the constant absolute angle of the bucket is maintained.

In order to control the bucket tip, if the position of the bucket tip 64 is (x ₃ , y ₃ ) and the length of the bucket is I ₃ and Θ _a is the angle of the bucket relative to the absolute horizontal plane, The position of the pivot point 63 is as follows.

The relative angles? ₁ and? ₂ of the boom 40 and the arm 50 in the aforementioned equations (1) and (2) are calculated using the position (x ₂ , y ₂ ) of the pivot point 63 determined here And the relative angle? ₃ of the bucket 60 with respect to the arm 50 is obtained by the following equation.

In order to maintain the angle of the bucket constant while controlling the speed of the bucket tip 64, the following equation is established. First, the speed V ₃ of the bucket tip 64 as required is represented by the speed V ₂ of the pivot point 63 of the bucket by the following formula.

The velocity (V ₂ ) of the pivot point 63 of the bucket obtained here is converted and controlled by the angular velocity of the boom and the arm joint according to equations (1) and (2). The following equation can be used as a method in which the tip 64 of the bucket follows the operating direction and the manipulated variable of the operating device while using the bucket in the full range without restricting the angle of the bucket to a certain angle. First, the following relationship exists between the angular velocity of each joint and the velocity of the bucket tip (64).

Here, J is as follows.

Here, the angular velocity [Θ] of each joint is obtained as follows.

As described above, various manipulation methods for intuitive manipulation of the manipulation device have been described.

In the first method, when the automatic mode is selected in the switch board 90, the amount of operation of the buckets 20, 22 and 24 is increased in proportion to the operating direction of the first 21, 22 and the second 23, 24 of the first operating device 20, The bucket is operated by the operation signal of the third operating direction when the bucket is operated.

The second method is that when the automatic mode 91 is selected and the bucket angle holding switch 94 is selected, the first (21, 22) and the second (23, 24) and the operation amount of the bucket by the operation signal of the third operation direction, the bucket is operated by this operation.

The third method is that when the flat work switch 92 is selected, the tip end 64 of the bucket (in the direction of the arrow) is proportional to the operating direction and the manipulated variable of the first 21, 22 and the second 23, 24 of the operating device 20 ), And if there is operation of the bucket by the third operation direction operation signal, the bucket is operated by this.

In the fourth method, when the flatness operation switch 92 is selected and the bucket angle maintaining switch is simultaneously selected, the absolute angle of the bucket 60 is kept constant by the operator, The tip end 64 of the bucket is followed in proportion to the operating direction and the manipulated variable of the first and second actuators 21 and 22 and the manipulation amount of the second actuator 23 and 24, This allows the bucket to be operated.

In the fifth method, when the flat operation switch 92 is selected and the switch 29 of the first operating device 20 is selected, the tip 64 of the bucket is moved in the second operating direction 23, 24 of the first operating device And a work plane having a predetermined angle set by the angle setting switch 93 of the switch board 90 in proportion to the operating direction.

The above-described five operating modes are displayed on the display unit 95 of the switchboard so that the operator can know the present operating mode.

Next, a control device related to the swing device and the traveling device as shown in Fig. 1 will be described.

The operation of the forward direction 31 during the operation of the first operating direction 31 and 32 in the second operating device 30 causes the right track 80 and the left track 190 to move forward And the operation in the backward direction 32 causes the right track 80 and the left track 190 to move backward (82, 192).

The operation in the rightward direction 33 of the second operation direction is an operation of moving the left track in the forward direction 81 and the right track in the backward direction 192 so as to bypass the apparatus, The track is operated in the backward direction 82 and the right track is moved in the forward direction 191 to turn the equipment left.

The operation of the clockwise direction 36 with respect to the X axis as the third operation direction of the second operation device 30 generates the speed of the upper sash in the clockwise direction 72 according to the operation amount and the operation of the counterclockwise direction 37 Turn the upper tilting system counterclockwise (73).

At this time, the turning safety switch 38 prevents an unintended turning operation by the operator during the operation of the first operation direction and the second operation direction.

Preferably, when the second operating device is used for traveling, as shown in FIG. 4, the position detectors 38 and 39 such as a dead angle measuring device installed in the operating device are disposed in the third direction, that is, Or in the normal direction with respect to the rear side 32, and in the case of forward or backward operation, the same output is generated.

The electric signal of the second manipulating device 30 that is sensitive to running is obtained when the relative angle of the upper rotating body 70 for the lower traveling body 79 measured by the linearizing sensor 75 using the controller 10 is 180 In the case of the forward movement of the second operation device 31, the forward movement of the track is controlled so as to allow the forward movement of the device. When the relative angle exceeds 180 degrees, In the case of the forward direction operation 32 of the second operation device, the track is controlled in the backward direction 82, 92 so that the equipment is aligned with the operation direction of the second operation device in the direction of the operator, Ensure that the concepts of operation are consistent.

As described above, according to the control apparatus for an excavator according to the present invention, by providing a pair of operating devices capable of operating in three directions, it is possible to easily operate the equipment of six degrees of freedom with only two hands to prevent fatigue and stress of the operator, And provides an operation method that can estimate the intuitive relationship between the operator and the working device, enabling skilled operation in a short period of time. By setting various operation functions, it is possible to provide highly skilled operation technology So that the efficiency of operation is always maintained.

FIG. 1 is a schematic view showing a turning control of an excavator and a control device for a traveling device according to an embodiment of the present invention;

FIG. 2 is a schematic view showing a control device for a working device of an excavator according to an embodiment of the present invention,

FIG. 3 is a simplified view of FIG. 2,

Fig. 4 is a schematic view showing the arrangement of the internal sensors of the operating device in Fig. 1;

Description of reference numerals used in the main parts of the drawings

10: Controller

20: First operating device

21, 22: First operating direction

23, 24: Second operating direction

26, 27: Third operating direction

30: Second operating device

31, 32: First operating direction

33, 34: Second operating direction

36, 37: Third operating direction

40: Boom

41, 51, 61: actuators

42, 52, 62: Hydraulic control valve

46, 56, 66: joint angle detection sensor

50: Cancer

60: Bucket

70: Upper revolving body

74, 84, 194: Hydraulic motor

76, 86, 196: Hydraulic control valve

79: Lower traveling body

80, 190: track

90: Switchboard

91: Mode selection switch

92: Flat working switch

93: Angle setting switch

94: Bucket angle holding switch

95: Display

100: working device

Claims (1)

A first operating direction for reciprocating with respect to the first axis, a second operating direction for reciprocating with respect to the second axis orthogonal to the first axis, a second operating direction for rotating about a third axis orthogonal to the plane formed by the first axis and the second axis, A first operating device provided on a vertical plane so as to have the same operating plane as a working plane of the working device so as to drive the working device in accordance with an operation amount and an operating direction; A first operating direction for reciprocating with respect to the first axis, a second operating direction for reciprocating with respect to the second axis orthogonal to the first axis, and a second operating direction for reciprocating about a third axis orthogonal to the plane formed by the first and second shafts And the operating directions of the three directions are operated so as to sequentially correspond to the front and rear travel of the traveling device and the left and right rotation of the traveling device and the left and right pivoting motion of the pivoting device, A second operating device installed on a horizontal plane so as to drive the traveling device and the turning device according to the direction; The relative angle of the boom and the arm and the relative angle of the arm and the bucket are detected and the first operation by the automatic operation is detected. A flat operation switch operable to allow the tip of the bucket to follow the first operation direction and the second operation direction of the apparatus and to control the bucket by the third operation direction and the operation amount; A bucket angle holding switch for determining whether to maintain the absolute angle of the bucket constant during operation; An angle setting switch for setting an angle of a flat surface to be worked in the case of a flat work; When the manual mode is selected, the first operation direction of the first operation device is the operation of the boom, the second operation direction is the operation of the arm, the third operation direction is the operation direction of the arm, And when the automatic mode is selected, the pivot point of the bucket is followed by the direction and the manipulated variable in the first and second operating directions of the first operating device, and at the same time, A mode selection switch which is controlled so that the bucket is operated by a direction and an operation amount; A display unit for displaying information such as an operation state and an operation mode of the equipment; A controller receiving a signal from each joint sensor and supplying a plurality of work device control signals to the hydraulic control valve to control a flow rate supplied to each actuator; A turning selection switch provided on a circumferential surface of the second operating device and capable of outputting a signal for a third operating direction by the second operating device to the controller in the ON state; A swing sensor installed between the upper swing body and the lower swing body to sense the relative angle of the upper swing body with respect to the lower swing body and output to the controller; A bucket selection switch provided on a circumferential surface of the first operating device so as to be able to output to the controller a signal of a direction and a manipulated variable in a third operating direction of the first operating device; A bucket angle holding switch for maintaining the absolute angle of the predetermined bucket and controlling the bucket in preference to an operator's operation when the bucket is operated at the same time and controlling the final angle of the bucket to an absolute angle to be followed again; And a switch installed at a front end of the first operating device under a condition connected to the controller such that a follow-up point based on a predetermined operating direction and an operating amount of the first operating device when the first operating device is turned on is operated on a working plane set by the angle setting switch And a control unit for controlling the operation of the multi-joint work unit.