Control device and program for work machine

Abstract

To appropriately prevent interference between the work implement and a cabin while allowing the work implement to continue operating even when a sensor that detects the angle of the work implement fails. [Solution] A control device is disclosed that includes a first acquisition unit that acquires sensor information according to the angle of the work implement, a failure detection unit, a second acquisition unit that acquires posture information, an interference prevention control unit that performs control to prevent interference between the work implement and the cabin, and a calculation unit that calculates the position of the pin based on the posture information, wherein a selection unit switches from the first mode to a second mode when a sensor failure is detected in the first mode, and in the first mode, the interference prevention control unit restricts the movement range of the work implement based on the sensor information and posture information so that the work implement does not enter a first restricted range, and in the second mode, the interference prevention control unit restricts the movement range of the pin based on the calculation result of the pin position so that the pin does not enter a second restricted range.

Description

[Technical Field]

[0001] The present disclosure relates to a control device and a program for a work machine. [Background technology]

[0002] In a work machine having a working implement, in which the working implement is supported rotatably about a pin relative to the working implement body, a cabin, and a power source, there is known a technique for preventing interference between the machine body (cabin, etc.) and the working implement by controlling the operation of the working implement when the working implement moves into a predetermined interference area between the working implement and the cabin. This technique allows the predetermined interference area to be selectively switched by operating a changeover switch, and in the event of a switch failure, the predetermined interference area is set to a non-minimum value. This makes it possible to prevent interference between the working implement and the machine body even in the event of a switch failure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-28908 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional technology cannot realize appropriate interference control for failures other than those of the change-over switch.

[0005] Therefore, an object of the present disclosure is to appropriately prevent interference between the work implement and the cabin while allowing the work implement to continue operating even when a sensor that detects the angle of the work implement fails. [Means for solving the problem]

[0006] According to one aspect, there is provided a control device for a work machine having a work device in which a work implement is supported on a work device body so as to be rotatable about a pin, a cabin, and a power source that operates the work device, a first acquisition unit that acquires sensor information related to an electrical signal from a sensor that generates an electrical signal according to an angle of the work implement with respect to the work device body; a failure detection unit that detects a failure of the sensor; a second acquisition unit that acquires posture information relating to the posture of the working device body; an interference prevention control unit that performs control to prevent interference between the work tool and the cabin; a selection unit that selects a first mode or a second mode as an operation mode of the interference prevention control unit; a setting unit that sets a first limit range in the first mode and sets a second limit range that is wider than the first limit range in the second mode; a calculation unit that calculates the position of the pin based on the attitude information, the selection unit switches from the first mode to the second mode when a failure of the sensor is detected in the first mode; In the first mode, the interference prevention control unit limits the movement range of the work tool based on the sensor information and the posture information so that the work tool does not enter the first restricted range, In the second mode, the interference prevention control unit limits the movement range of the pin based on the calculation result of the position of the pin so that the pin does not enter the second limit range. [Effects of the Invention]

[0007] According to the present disclosure, even in the event of a failure of a sensor that detects the angle of the work implement, it is possible to appropriately prevent interference between the work implement and the cabin while allowing the work implement to continue operating. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a diagram illustrating a driving element of a construction machine equipped with a control device of the present embodiment. [Figure 2] FIG. 1 is a diagram illustrating a mechanism of a construction machine. [Figure 3] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device according to the present embodiment. [Figure 4] FIG. 2 is a diagram functionally illustrating the configuration of a control device according to the present embodiment. [Figure 5] FIG. 10 is an explanatory diagram of a first restricted range. [Figure 6] FIG. 10 is an explanatory diagram of a second restricted range. [Figure 7] 4 is a schematic flowchart showing an example of the flow of main processes that may be executed by the control device of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings.

[0010] FIG. 1 is a diagram illustrating the driving elements of a construction machine 1 equipped with a control device 10 of this embodiment, and FIG. 2 is a diagram illustrating the mechanism of the construction machine 1. As shown in FIG.

[0011] 1, a construction machine 1 equipped with the control device 10 of this embodiment is configured to include, as drive elements, a hydraulic oil tank 21, an engine 22, a hydraulic pump 23 driven by the engine 22, a tilt proportional valve 24 that controls the tilt of the hydraulic pump 23, a control valve unit 25, and various actuators 27. Hydraulic oil circulates from the hydraulic oil tank 21 via the hydraulic pump 23, the control valve unit 25, and various actuators 27, returning to the hydraulic oil tank 21.

[0012] 1, the engine 22 is used, but an electric motor may be used instead of or in addition to the engine 22. Also, an electric pump may be used instead of or in addition to the hydraulic pump 23.

[0013] FIG. 2 shows a hydraulic excavator as an example of the construction machine 1.

[0014] This hydraulic excavator includes a lower traveling body 41 that can travel on the ground, an upper rotating body 42 mounted on the lower traveling body 41, and a working device 50 mounted on the upper rotating body 42.

[0015] The upper rotating body 42 has a rotating frame 42a and multiple elements mounted thereon. These multiple elements include an engine room 42b that houses the engine 22 (FIG. 1) and a cab 42c (cabin) that serves as a driver's compartment. The cab 42c is equipped with a space where an operator can get in and operating tools (not shown). In the case of an automatic type of construction machine that does not require an operator, the cab 42c may also refer to a space where the machine and other components are placed.

[0016] The working device 50 is capable of performing operations for excavation work and other necessary work, and includes, as operating elements, a boom 51, an arm 52, and an attachment 53. In this specification, the portion of the working device 50 excluding the attachment 53 is an example of the working device main body.

[0017] The boom 51 is supported at the front end of the revolving frame 42a so as to be able to rise and fall, that is, to be able to rotate about a horizontal axis.

[0018] The arm 52 is attached to the tip of the boom 51 so as to be rotatable around a horizontal axis.

[0019] The attachment 53 is rotatably attached to the tip of the arm 52. In the example shown in Fig. 2, the attachment 53 is a bucket, but it may have other shapes or names, such as a fork, a crusher, a breaker, or a cutter (see Fig. 5, etc.). In other words, this embodiment can be used for any work machine other than the hydraulic excavator shown in Fig. 2.

[0020] In addition, a plurality of hydraulic cylinders serving as extendable driving elements (actuators), specifically at least one boom cylinder 61, arm cylinder 62 and bucket cylinder 63, are provided corresponding to the boom 51, arm 52 and attachment 53, respectively.

[0021] The boom cylinder 61, arm cylinder 62, and bucket cylinder 63 are contracted to lower the boom, push the arm, and open the bucket, respectively. On the other hand, the boom cylinder 61, arm cylinder 62, and bucket cylinder 63 are extended to raise the boom, pull the arm, and close the bucket, respectively. Note that the extension and contraction directions of the boom cylinder 61, arm cylinder 62, or bucket cylinder 63 may be combined arbitrarily with the rotation directions of the boom 51, arm 52, or attachment 53.

[0022] A sensor 42d is attached to the upper rotating body 42 to detect the inclination (angle with respect to the horizontal plane) of the upper rotating body 42. A sensor 51a is attached to the base end of the boom 51 to detect the angle of the boom 51 with respect to the upper rotating body 42. A sensor 52a is attached to the base end of the arm 52 to detect the angle of the arm 52 with respect to the boom 51, and a sensor 53a is attached to the base end of the attachment 53 to detect the angle of the attachment 53 with respect to the arm 52. The sensor 51a, the sensor 52a, or the sensor 53a may be attached at any position and does not have to be at the base end of the boom 51, the arm 52, or the attachment 53. A sensor that detects the inclination of the lower traveling body 41 may be attached instead of or in addition to the sensor 42d attached to the upper rotating body 42. In a configuration that includes an arm-side jib 512 (see FIG. 5, etc.), such as a two-piece boom, a sensor that calculates the angle of the arm-side jib 512 may be further included.

[0023] In the hydraulic excavator shown in Fig. 2, at least the boom cylinder 61, the arm cylinder 62, and the bucket cylinder 63 are operated via various actuators 27. In this case, the control valve unit 25 shown in Fig. 1 is connected to the various actuators 27 associated with the boom cylinder 61, the arm cylinder 62, and the bucket cylinder 63. In this case, the control valve unit 25 may be formed as an assembly of a plurality of control valves that respectively control the extension and contraction of the boom cylinder 61, the arm cylinder 62, and the bucket cylinder 63.

[0024] FIG. 3 is a diagram illustrating an example of a hardware configuration of the control device 10. As shown in FIG.

[0025] 3, the control device 10 includes a control unit 101, a main memory unit 102, an auxiliary memory unit 103, a drive device 104, a network I / F unit 106, and an input unit 107. Note that part or all of the control device 10 may be in the form of a circuit in which various elements (including elements in the form of chips) are mounted on a substrate or the like.

[0026] The control unit 101 is a calculation device that executes programs stored in the main memory unit 102 and the auxiliary memory unit 103, and receives data from the input unit 107 or a storage device, calculates and processes it, and then outputs it to a storage device or the like.

[0027] The main memory unit 102 is a read-only memory (ROM), a random access memory (RAM), etc. The main memory unit 102 is a storage device that stores or temporarily saves programs and data, such as an operating system (OS), which is basic software executed by the control unit 101, and application software.

[0028] The auxiliary storage unit 103 is a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores data related to application software and the like.

[0029] The drive device 104 reads the program from a recording medium 105, such as a flexible disk, and installs it in a storage device.

[0030] A predetermined program is stored in the recording medium 105. The program stored in the recording medium 105 is installed in the control device 10 via the drive device 104. The installed predetermined program can be executed by the control device 10.

[0031] The network I / F unit 106 is an interface between the control device 10 and peripheral devices having a communication function connected via a network constructed by a data transmission path such as a wired and / or wireless line.

[0032] The input unit 107 includes a keyboard equipped with cursor keys, a numeric keypad (numeric input keys), various function keys, a mouse, a touch pad, and the like.

[0033] 3, the various processes described below can be realized by causing the control device 10 to execute a program. Alternatively, the program can be recorded on a recording medium 105, and the control device 10 can read the program from the recording medium 105 to realize the various processes described below. Various types of recording media can be used for the recording medium 105. For example, the recording medium 105 may be a recording medium that records information optically, electrically, or magnetically, such as a CD (Compact Disc)-ROM, a flexible disk, or a magneto-optical disk, or a semiconductor memory that records information electrically, such as a ROM or a flash memory.

[0034] In this embodiment, the control device 10 can be realized by one computer, but may also be realized by a combination of multiple computers. Also, an external server computer may be used.

[0035] Fig. 4 is a diagram functionally illustrating the configuration of the control device 10 of this embodiment. Fig. 5 is an explanatory diagram of the first restricted range S1, and Fig. 6 is an explanatory diagram of the second restricted range S2. Note that the shape of the attachment 53 in Figs. 5 and 6 is different from the example shown in Fig. 2, but this difference is not essential.

[0036] The control device 10 includes a failure detection unit 11, an attitude acquisition unit 12, a mode selection unit 13, a limited range setting unit 14, a reference position calculation unit 15, a device control unit 18, and a notification unit 19.

[0037] Each unit from the fault detection unit 11 to the device control unit 18 can be realized by the control unit 101 shown in Figure 3 executing one or more programs stored in the main memory unit 102 and / or the auxiliary memory unit 103 and / or the recording medium 105 shown in Figure 3.

[0038] The fault detection unit 11 detects various faults that affect the control functions of the device control unit 18, which will be described later. In this embodiment, the fault detection unit 11 detects a fault in the sensor 53a as one of the various faults. Note that the term "failure" is a concept that includes abnormality. The fault detection unit 11 may determine the possibility of a fault in the sensor 53a instead of or in addition to determining whether or not the sensor 53a has a fault. In this case, a state in which the possibility of a fault in the sensor 53a exceeds a threshold may be synonymous with a state in which a fault in the sensor 53a has been detected.

[0039] The attitude acquisition unit 12 acquires sensor information relating to the attitude of the working device 50. The sensor information relating to the attitude includes angles detected by the sensor 42d, the sensor 51a, the sensor 52a, and the sensor 53a.

[0040] In this specification, the sensor information related to the attitude of the construction machine 1 other than the sensor information from sensor 53a is also collectively referred to as "attitude information." In other words, the sensor information from sensors 42d, 51a, and 52a is also referred to as attitude information.

[0041] The mode selection unit 13 selects (sets) one of various operation modes of the construction machine 1. The mode selection unit 13 may select the operation mode in response to a user input and / or automatically. In this embodiment, the various operation modes include the following two modes associated with the control mode of the device control unit 18: an unrestricted mode (an example of a first mode) that can be selected when no failure of the sensor 53a is detected, and a restricted mode (an example of a second mode) that is implemented when a failure of the sensor 53a is detected. When the operation mode is the unrestricted mode and the failure detection unit 11 detects a failure of the sensor 53a, the mode selection unit 13 switches the operation mode from the unrestricted mode to the restricted mode. Note that the mode selection unit 13 may switch the operation mode from the unrestricted mode to the restricted mode in response to a user input when the operation mode is the unrestricted mode.

[0042] The limited range setting unit 14 sets a limited range (area) for the operation of the working device 50. The limited range is defined relative to a reference part of the working device 50 or a reference position related to the working device 50. The limited range is in the form of a prohibited range that does not include the reference part or the reference position. However, in a modified example, the limited range may be defined substantially by defining a movable range that does not allow the reference part or the reference position to protrude.

[0043] In this embodiment, the restricted range setting unit 14 sets a first restricted range S1 in the non-restricted mode, and sets a second restricted range S2 that is wider than the first restricted range S1 in the restricted mode.

[0044] The first restricted range S1 is defined with respect to the attachment 53 of the working device 50 as a reference portion of the working device 50. For example, as shown in FIG. 5 , the reference portion of the working device 50 is assumed to be a polygon (e.g., a rectangle) that circumscribes the outer shape of the attachment 53 in a side view. Hereinafter, such a polygon is also referred to as an attachment area 81. Note that, in a modified example, the reference portion of the working device 50 may be a point such as the tip 53b of the attachment 53 or a narrower portion.

[0045] 5, the first restricted range S1 may be defined by a boundary line 91 that covers the cab 42c (covers the attachment 53 side) in a side view, and the area closer to the cab 42c than the boundary line 91 becomes the first restricted range S1. Note that the boundary line 91 may have a closed shape such as a circle, or may be defined as a range that corresponds to the effective range.

[0046] In this embodiment, the boundary line 91 is preferably a circular arc. In this case, the center of the arc (center of curvature) may be set behind the cab 42c. In this case, the radius of the arc can be made relatively large, and the boundary line 91 can be defined to follow the front shape of the cab 42c in a side view (a relatively linear front shape).

[0047] 6, the second restricted range S2 is defined with respect to a pin 70 of the working device 50 as a reference position for the working device 50. The pin 70 forms a rotation axis that rotatably supports the attachment 53 with respect to the arm 52. The sensor 53a described above detects the angle of the attachment 53 with respect to the arm 52, that is, the angle around the pin 70.

[0048] 6, the second restricted range S2 may be defined by a boundary line 92 that covers the cab 42c (covers the attachment 53 side) in a side view, and the second restricted range S2 is the area closer to the cab 42c than the boundary line 92. In this case, as described above, the second restricted range S2 is wider than the first restricted range S1 and substantially includes the first restricted range S1.

[0049] The second limit range S2 may be adapted so that when the pin 70 is positioned on or near the boundary line 92, the attachment 53 will not hit the cab 42c regardless of the angle of the attachment 53 relative to the arm 52 (any angle within the movable range).

[0050] In this embodiment, the boundary line 92 is preferably an arc. In this case, the center of the arc relating to the boundary line 92 may coincide with the center of the arc relating to the boundary line 91. In other words, the arc relating to the boundary line 92 and the arc relating to the boundary line 91 may be concentric. In this case, the number of parameters that manage the first limited range S1 and the second limited range S2 can be reduced, thereby reducing the processing load and the required storage capacity.

[0051] The reference position calculation unit 15 operates when the operation mode is the restricted mode. The position of the pin 70 of the working device 50 is calculated as the reference position for the working device 50. The position of the pin 70 can be calculated based on the sensor information related to the attitude described above. However, any method for calculating the position of the pin 70 may be used. For example, instead of or in addition to the angle detected by the sensor 53a, the position of the pin 70 may be calculated based on a cylinder stroke acquired by a cylinder equipped with a stroke sensor. Also, a method of calculating the position of the pin 70 using a GNSS (Global Navigation Satellite System) or a method of detecting the position based on a photographed image of the pin 70 or the like may be used. The position of the pin 70 may also be calculated taking into account the hydraulic pressure of the cylinder during operation.

[0052] The device control unit 18 controls the working device 50 in response to input from the operator. The device control unit 18 may also control the working device 50 automatically or semi-automatically.

[0053] In this embodiment, the device control unit 18 determines whether the restriction condition based on the first restriction range S1 or the second restriction range S2 is met while controlling the operation of the working device 50 in response to input from the operator. Then, when the restriction condition is met, the device control unit 18 executes restriction control to restrict the operation of the working device 50 regardless of input from the operator.

[0054] The limit control is a control for preventing the attachment 53 and the like from entering the first limit range S1 or the second limit range S2. The limit control is optional and may include, for example, stopping or slowing down the work implement 50. For example, the limit control limits the movement of the attachment 53 in a direction that would move the attachment 53 further into the first limit range S1 or the second limit range S2 by outputting an alarm, stopping or slowing down the work implement 50, etc. For example, in the case of the bucket cylinder 63, the movement of the bucket excavation side may be stopped or slowed down.

[0055] When the operating mode is the non-restricted mode, the device control unit 18 executes restriction control based on the angle detected by the sensor 53a and the posture information to prevent the attachment 53 from entering the first restricted range S1. That is, the restriction control restricts the movement range of the attachment 53 to prevent the attachment 53 from entering the first restricted range S1. Note that "preventing the attachment 53 from entering the first restricted range S1" not only includes the concept of completely preventing the attachment 53 from entering the first restricted range S1, but also the concept of preventing the attachment 53 from entering the first restricted range S1 as much as possible. Therefore, "preventing the attachment 53 from entering the first restricted range S1" may also include the concept of "preventing the attachment 53 from leaving the first restricted range S1."

[0056] Specifically, when the operating mode is the non-restricted mode, the device control unit 18 performs restriction control so that the attachment area 81 (see FIG. 5) does not enter the first restricted range S1 (or if it does enter, so that it leaves).

[0057] When the operation mode is the limited mode, the device control unit 18 cannot use the angle detected by the sensor 53a. Therefore, when the operation mode is the limited mode, the device control unit 18 executes limit control based on the calculation result of the position of the pin 70 to prevent the pin 70 from entering the second limited range S2. That is, the limit control limits the movement range of the pin 70 to prevent the pin 70 from entering the second limited range S2. Note that "preventing the pin 70 from entering the second limited range S2" not only includes the concept of completely preventing the pin 70 from entering the second limited range S2, but also the concept of preventing the pin 70 from entering the second limited range S2 as much as possible. Therefore, "preventing the pin 70 from entering the second limited range S2" may also include the concept of "preventing the pin 70 from leaving the second limited range S2."

[0058] The notification unit 19 provides various notifications to the operator. The various notifications are optional, and may, for example, notify the operator of the state in which the above-mentioned limit control is being executed (limit mode), or may notify the operator when the non-limit mode is switched to the limit mode. The notification method is optional and may be realized acoustically and / or optically. Note that optical notifications may be notifications using light, images, video, etc. The notification unit 19 may also output an alarm related to the limit control.

[0059] In this embodiment, the mode of limit control may be selectable by the operator from several modes. In this case, for example, if a mode with a relatively low degree of intervention (e.g., an alarm) is selected, the relationship between the second limit range S2 and the position of the pin 70 may be displayed on a display (not shown) or the like.

[0060] In this embodiment, the limit control may be released by an input from the operator (for example, by operating a button). In this case, the relationship between the second limit range S2 and the position of the pin 70 may be displayed on a display (not shown) or the like.

[0061] Incidentally, since the sensor 53a is attached closer to the attachment 53 than the other sensors (for example, the sensor 52a, etc.), it tends to malfunction more easily than the other sensors. For example, it tends to interfere with rocks or the like during work, which can easily cause malfunctions such as broken wires.

[0062] In this regard, in this embodiment, when a failure of the sensor 53a is detected, the operation of the working implement 50 can be continued in the restricted mode. In the restricted mode, the restricted control is executed based on the relationship between the second restricted range S2 and the position of the pin 70, so that interference between the attachment 53 and the cab 42c can be appropriately prevented even in a situation where sensor information cannot be obtained from the sensor 53a.

[0063] In this way, according to this embodiment, even in the event of a failure of the sensor 53a that detects the angle of the attachment 53, it is possible to continue operating the attachment 53 while appropriately preventing interference between the attachment 53 and the cab 42c.

[0064] In this embodiment, as described above, even if the sensor 53a that detects the angle of the attachment 53 fails, the operation of the attachment 53 can continue, so in the case of an ultra-long building demolition machine, for example, the attachment 53 can be lowered to the ground to repair the sensor 53a.

[0065] Next, an example of the operation of the control device 10 of this embodiment will be described with reference to FIG.

[0066] 7 is a schematic flowchart showing an example of the flow of main processes that may be executed by the control device 10 of this embodiment. For the sake of simplicity, it is assumed here that there are only two possible operation modes: a restricted mode and an unrestricted mode.

[0067] In step S700, the control device 10 acquires sensor information relating to the attitude of the working device 50.

[0068] In step S702, the control device 10 determines whether the operation mode is the non-restricted mode. If the determination result is "YES", the process proceeds to step S704, and otherwise (i.e., if the operation mode is the restricted mode), the process proceeds to step S710.

[0069] In step S704, the control device 10 determines whether a failure of the sensor 53a has been detected. Note that any method for determining a failure of the sensor 53a may be used. For example, a failure of the sensor 53a may be detected when the electrical signal from the sensor 53a is interrupted or when the value (angle) indicated by the electrical signal is abnormal. If the determination result is "YES," the process proceeds to step S706; otherwise, the process proceeds to step S708.

[0070] In step S706, the control device 10 switches the operation mode from the non-restricted mode to the restricted mode, and then proceeds to step S710.

[0071] In step S708, the control device 10 operates in the non-restricted mode. Specifically, the control device 10 determines whether the restriction condition based on the first restricted range S1 is met while controlling the operation of the working device 50 in response to input from the operator. The restriction condition based on the first restricted range S1 is arbitrary, but may be met, for example, when the attachment area 81 approaches the first restricted range S1 within a predetermined distance D1. Then, when the restriction condition is met, the device control unit 18 executes the restriction control described above regardless of input from the operator.

[0072] In step S710, the control device 10 calculates the position of the pin 70 based on the attitude information obtained in step S700.

[0073] In step S712, the control device 10 operates in the restricted mode. Specifically, the control device 10 determines whether the restricted condition based on the second restricted range S2 is met while controlling the operation of the working device 50 in response to input from the operator. The restricted condition based on the second restricted range S2 is arbitrary, but may be met, for example, when the pin 70 approaches the second restricted range S2 within a predetermined distance D2. Note that the predetermined distance D2 may be the same as or different from the predetermined distance D1 in step S708 described above. Then, when the restricted condition is met, the device control unit 18 executes the restricted control described above regardless of input from the operator.

[0074] The limit control that can be executed in step S712 may be the same as or different from the limit control that can be executed in the above-described step S708. For example, the limit control that can be executed in step S712 may be more restrictive than the limit control that can be executed in the above-described step S708.

[0075] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0076] For example, in the above-described embodiment, the second limit range S2 may be changed depending on the type of attachment 53, or may be set uniformly without depending on the type of attachment 53. In this case, the second limit range S2 may be set based on the type of attachment 53 that has the largest physical size in a side view among the various types of attachments 53 that can be attached.

[0077] Furthermore, although the above-described embodiment deals with a failure of the sensor 53a, the present invention can also be applied to failures of the other sensors 51a and 52a. For example, when a failure of the sensor 52a is detected, the movement of the arm 52 in a direction corresponding to the side where interference with the cab 42c occurs may be restricted. For example, in the case of the arm cylinder 62, the movement in a direction corresponding to the pulling side of the arm 52 may be restricted. In this case, the control related to the restriction may be any of the following, similar to the above-described limit control: an alarm, deceleration, stop, etc.

[0078] Furthermore, in the above-described embodiment, the boom 51 is a one-piece boom, but it may be of another form, such as a two-piece boom. In the case of a two-piece boom, if a failure of the sensor 52a is detected in addition to a failure of the sensor 53a, a third restricted area S3 (not shown) that is wider than the second restricted area S2 may be set, and the reference position may be changed from the position of the pin 70 at the tip of the arm 52 to the position of the pin at the tip of the jib (the pin associated with the sensor 52a). [Explanation of symbols]

[0079] 1. Construction machinery 42c Cab (cabin) 50 Work equipment 53 Attachments (Work Tools) 70 pins 53a Sensor 10 Control device 11 Fault detection section 12 Attitude acquisition part (1st acquisition part, 2nd acquisition part) 13 Mode selection section (selection section) 14 Restriction range setting section 15 Reference position calculation section 18 Device control section (interference prevention control section) 19 Notification Department S1 First restricted range 91 Boundary line (arc) S2 Second limit range 92 Boundary line (arc)

Claims

1. A control device for a work machine having a work device in which a work implement is supported on a work device body so as to be rotatable about a pin, a cabin, and a power source that operates the work device, a first acquisition unit that acquires sensor information related to an electrical signal from a sensor that generates an electrical signal according to an angle of the work tool with respect to the work device body; a failure detection unit that detects a failure of the sensor; a second acquisition unit that acquires posture information relating to the posture of the working device body; an interference prevention control unit that performs control to prevent interference between the work tool and the cabin; a selection unit that selects a first mode or a second mode as an operation mode of the interference prevention control unit; a setting unit that sets a first limit range in the first mode and sets a second limit range that is wider than the first limit range in the second mode; a calculation unit that calculates the position of the pin based on the attitude information, the selection unit switches from the first mode to the second mode when a failure of the sensor is detected in the first mode; In the first mode, the interference prevention control unit limits the movement range of the work tool based on the sensor information and the posture information so that the work tool does not enter the first restricted range, In the second mode, the interference prevention control unit limits the movement range of the pin based on the calculation result of the position of the pin so that the pin does not enter the second limit range.

2. The control device according to claim 1 , wherein the second limit range is defined by an arc that lies in a plane along the direction of movement of the work implement and at least partially surrounds the cabin.

3. the first limit range is defined by an arc in a plane along the direction of movement of the work implement; The control device according to claim 2 , wherein the arc of the second limit range is concentric with the arc of the first limit range.

4. The control device according to claim 1 , wherein in the second mode, the interference prevention control section limits the allowable direction of angle change of the implement to one direction.

5. The control device according to claim 1 , further comprising a notification unit that notifies an operator of the operation mode selected by the selection unit.

6. A program that causes a computer to execute a control method for a work machine having a work device in which a work implement is supported on a work device body so as to be rotatable about a pin, a cabin, and a power source that operates the work device, The control method includes: a first acquisition step of acquiring sensor information relating to an electrical signal from a sensor that generates an electrical signal in accordance with an angle of the work implement relative to the work device body; a fault detection step of detecting a fault in the sensor; a second acquisition step of acquiring posture information relating to the posture of the working device body; a control step of performing control to prevent interference between the work implement and the cabin; a selection step of selecting a first mode or a second mode as an operation mode of the control step; a setting step of setting a first limit range in the first mode and setting a second limit range wider than the first limit range in the second mode; a calculation step of calculating the position of the pin based on the attitude information, the selecting step includes switching from the first mode to the second mode when a failure of the sensor is detected in the first mode; In the first mode, the control step includes limiting a movement range of the work tool based on the sensor information and the posture information so that the work tool does not enter the first restricted range; In the second mode, the control step limits the movement range of the pin based on the calculation result of the position of the pin so that the pin does not enter the second limit range.

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