Construction machine

A construction machine includes a boom, an operator cab, a distance sensor, a displacement detection unit, a storage unit, and a position information acquisition unit. The distance sensor has a predetermined field of view and acquires distance image data indicating a distance distribution of an environment around the operator cab. The storage unit stores initial position information of the boom. The displacement detection unit compares comparative position information of the boom, the comparative position information being acquired from the distance image data by the position information acquisition unit, with initial position information of the boom stored in the storage unit to detect a displacement of the distance sensor with respect to the operator cab when the boom is brought into an initial posture again after initial setting.

TECHNICAL FIELD

The present invention relates to a construction machine provided with a detection unit.

BACKGROUND ART

In a construction machine, an attachment other than an attachment intended by a manufacturer of the construction machine may be attached by a user. Further, in a construction machine such as a demolition machine, a member of a demolished building may be held by an attachment. In these cases, there is an increased possibility that the attachment or the member of the demolished building interferes with an operator cab as an interfering object. Accordingly, it is necessary to prevent the interference. Thus, a sensor is attached to the body of the construction machine to detect a distance between the operator cab and the interfering object to prevent the interference of the interfering object with the operator cab.

Patent Literature 1 discloses an interference prevention device which determines whether a bucket has entered an interference dangerous area set in front of an operator cab using a plurality of ultrasonic sensors. Patent Literature 2 discloses a technique in which a wide area camera detects the color of a safety belt worn by an operator, and when the color is detected, it is determined whether the operator is present in an operating range of a work machine using a laser rangefinder. Patent Literature 3 discloses a technique in which a first stereo camera and a second stereo camera are attached with a predetermined interval therebetween to an upper part in a front direction of a cabin of a hydraulic excavator, and an obstacle is detected on the basis of stereo images captured by these stereo cameras.

CITATION LIST

Patent Literature

Patent Literature 1: JP 2001-64992 A

Patent Literature 2: JP 2012-225111 A

Patent Literature 3: JP 2014-215039 A

SUMMARY OF INVENTION

In the techniques disclosed in Patent Literatures 1 to 3, the position of the sensor may be displaced along with the use of the construction machine (displacement). In particular, when the position of the sensor is displaced from the position at the time of shipment from a factory by vibrations of the construction machine or an external force applied to the machine body, there is a problem in that the sensor cannot correctly grasp an environment around the construction machine.

It is an object of the present invention to provide a construction machine capable of detecting a displacement of a detection unit.

A construction machine according to one aspect of the present invention includes: a first structure; a second structure relatively rotatable around a predetermined shaft relative to the first structure; a detection unit that is disposed on the first structure, has a predetermined detection range, and detects environment data indicating information of an environment around the first structure; a position information acquisition unit that acquires position information of a specific part of the second structure with respect to the detection unit from the environment data detected by the detection unit; a storage unit capable of storing initial position information of the specific part, the initial position information being acquired from the environment data by the position information acquisition unit, and outputting the initial position information at initial setting when the second structure is disposed at an initial posture around the shaft, the initial posture being previously set so that the second structure is included in the detection range of the detection unit; and a displacement detection unit that compares comparative position information of the specific part, the comparative position information being acquired from the environment data by the position information acquisition unit, with the initial position information output from the storage unit to detect a displacement of the detection unit in the first structure when the second structure is brought into the initial posture again after the initial setting.

DESCRIPTION OF EMBODIMENTS

Hereinbelow, each embodiment of the present invention will be described with reference to the drawings.FIG. 1is a schematic side view of a construction machine1according to an embodiment of the present invention. Hereinbelow, a front direction, a rear direction, a left direction, a right direction, an up direction, and a down direction are based on a direction viewed from an operator cab31. Further, the front direction and the rear direction are collectively described as a front-rear direction, and the up direction and the down direction are collectively described as an up-down direction. Further, the left direction and the right direction are collectively described as a right-left direction.

The construction machine1includes a crawler-type lower traveling body2, an upper slewing body3(an example of a first structure and a vehicle body) which is slewably disposed on the upper part of the lower traveling body2, and a work attachment4(an example of a second structure) whose posture is changeable, the work attachment4being attached to the upper slewing body3. An upper body32is disposed on the upper slowing body3in addition to the operator cab31.

The work attachment4is disposed adjacent to, for example, the right side of the operator cab31, and raisably and lowerably attached to the upper slewing body3. The work attachment4includes a boom15, an arm16which is swingably attached to the distal end of the boom15, and a bucket17(holding attachment) which is swingably attached to the distal end of the arm16(the distal end side of the boom15). The bucket17is capable of holding a predetermined held object. Each of the boom15, the arm16, and the bucket17is capable of changing its posture by rotating around a predetermined shaft extending in a horizontal direction. In particular, the upper slewing body3rotatably supports the boom15. In other words, the boom15is relatively rotatable around a predetermined shaft4A relative to the upper slewing body3. In addition to the bucket, a crusher and a demolition machine can be employed as the work attachment4.

The upper slewing body3includes the operator cab31which is a box body and is occupied by an operator. In the operator cab31, a face on the front side is defined as a front lace31aand a face on the upper side is defined as an upper face31b(FIG. 1).

A warning area D1and an automatic restriction area D2are set in this order from the front side in front of the operator cab31. The warning area D1is an area for notifying the operator that danger is approaching due to an interfering object approaching the operator cab31or restricting the operation of the work attachment4when the interfering object has entered the warning area D1. The automatic restriction area D2is an area for automatically stopping or restricting the operation of the work attachment4when an interfering object has entered the automatic restriction area D2.

The warning area D1is defined by a boundary surface L1and a boundary surface L2. The boundary surface L1includes a boundary surface L11which faces the front face31aand a boundary surface L12which faces the upper face31b. The boundary surface L11is a plane which is set parallel to the front face31aat a position away from the front face31ato the front side by a distance d11. The boundary surface L12is a plane which is set parallel to the upper lace31bat a position away from the upper face31bto the upper side by the distance d11.

The automatic restriction urea D2is defined by the boundary surface L2, the front face31a, and the upper face31b. The boundary surface L2includes a boundary surface L21which faces the front face31aand a boundary surface L22which faces the upper face31b. The boundary surface L21is a plane which is set parallel to the front face31aat a position away from the front face31ato the front side by a distance d12(<d11). The boundary surface L22is a plane which is set away from the upper face31bto the upper side by the distance d12.

The lowermost ends of the warning area D1and the automatic restriction area D2are located in front of the lower part of the operator cab31. Further, the width in the right-left direction of each of the warning area D1and the automatic restriction area D2is set to the width in the right-left direction of the front face31aor a width obtained by adding some margin to the width in the right-left direction of the front face31a. However, these configurations are merely examples, and the position of the lowermost end and the width in the right-left direction of each of the warning area D1and the automatic restriction area D2may not be defined. Further, the warning area D and the automatic restriction area D2may be set only in front of the front face31aand may not be set above the upper face31b. A three-dimensional coordinate system in which the warning area D and the automatic restriction area D2are set is defined as a three-dimensional coordinate system of the construction machine1.

A distance sensor110is disposed on the front face31aof the operator cab31at a predetermined position (here, the upper end). The distance sensor110has a predetermined field of view (detection range) and acquires distance image data indicating a distance distribution of an environment around (here, on the front side of) the upper slewing body3. Specifically, the distance sensor110is disposed on the front face31ain such a manner that a measurement range thereof can cover the entire area of the boundary surface L21. Accordingly, there is no dead angle of the distance sensor110in the warning area D1which faces the front face31a. Thus, the construction machine1is capable of giving a warming to the operator before an interfering object enters the automatic restriction area D2. The distance sensor110constitutes a detection unit of the present invention.

The construction machine1further includes a first angle sensor101, a second angle sensor102, and a third angle sensor103. The first angle sensor101is disposed on a rotation supporting point (shaft4A) of the boom15to measure a rotation angle of the boom15around the shaft. The second angle sensor102is disposed on a rotation supporting point of the arm16to measure a rotation angle of the arm16around the shaft. The third angle sensor103is disposed on a rotation supporting point of the bucket17to measure a rotation angle of the bucket17around the shaft.

The upper slewing body3is provided with a controller120which is electrically connected to the distance sensor110to control the entire construction machine1. Further, a notification unit140is disposed inside the operator cab31. The notification unit140notifies the operator of a state of the construction machine1under the control of the controller120.

FIG. 2is a block diagram illustrating an example of a system configuration of the construction machine1illustrated inFIG. 1. The construction machine1includes an engine210, a hydraulic pump250and a generator motor220which are coupled to an output shaft of the engine210, a control valve260which controls the supply and discharge of a hydraulic oil with respect to a hydraulic cylinder271through the hydraulic pump250, a power storage device240which is capable of being charged with electric power generated by the generator motor220, and an inverter230which performs electric power conversion between the power storage device240and the generator motor220.

The hydraulic pump250is operated by the power of the engine210and discharges a hydraulic oil. The hydraulic oil discharged from the hydraulic pump250is guided to the hydraulic cylinder271at a flow rate controlled by the control valve260. A pilot valve and a proportional valve are disposed inside the control valve260.

The controller120includes a valve adjustment unit126(FIG. 2) which sets an opening degree of the proportional valve inside the control valve260in accordance with an operation amount of an operation lever130.

The hydraulic cylinder271extends and contracts with the hydraulic oil supplied thereto. Each of a boom cylinder which raises and lowers the boom15with respect to the upper slewing body3, an arm cylinder which swings the arm16with respect to the boom15, and a bucket cylinder which swings the bucket17with respect to the arm16constitutes an example of the hydraulic cylinder271. Each of the cylinders is provided with the control valve260described above. Each of the cylinders can be independently controlled upon receipt of a control signal of the controller120.

The generator motor220is provided with a configuration as a generator which converts the power of the engine210to electric power and a configuration as a motor which converts electric power stored in the power storage device240to power. In the example ofFIG. 2, the generator motor220includes, for example, a three-phase motor. However, this is merely an example, and the generator motor220may include a single-phase motor.

Examples of the power storage device240include various secondary batteries such as a lithium ion battery, a nickel-metal hydride battery, an electric double layer capacitor, and a lead battery.

The inverter230controls switching between an operation of the generator motor220as a generator and an operation of the generator motor220as a motor under the control of the controller120. Further, the inverter230controls current to the generator motor220and a torque of the generator motor220under the control of the controller120. In the example ofFIG. 2, the inverter230includes, for example, a three-phase inverter. However, this is merely an example, and the inverter230may include a single-phase inverter.

FIG. 3is a diagram illustrating the work attachment4in a simplified manner.FIG. 4is a flowchart illustrating a process at initial setting of the construction machine1in the present embodiment.FIG. 5is a diagram illustrating distance image data including the work attachment4superimposed on a coordinate area of the construction machine1.FIG. 6is a flowchart illustrating a process (displacement determination process) during the use of the construction machine1.

The construction machine1further includes an acquisition unit100(posture information acquisition unit) (FIG. 2), the distance sensor110, the controller120, and the notification unit140which are illustrated inFIG. 1, and the operation lever130which receives an operation for changing the posture of the work attachment4by the operator (FIG. 2).

The acquisition unit100includes the first angle sensor101, the second angle sensor102, and the third angle sensor103which are described above with reference toFIG. 1, and acquires posture information indicating the posture of the work attachment4(second structure). Here, the rotation angle of the boom15, the rotation angle of the arm16, and the rotation angle of the attachment17correspond to the posture information.

The distance sensor110is disposed in such a manner that a field of view thereof includes the front side of the operator cab31, and measures the distance from the distance sensor110to an object located around the operator cab31. In the present embodiment, the distance sensor110includes, for example, a depth sensor which is provided with a light source which applies infrared rays, a camera which is capable of receiving infrared rays and visible light, and a processor which processes image data captured by the camera. The distance sensor110, for example, applies infrared rays at each certain time (e.g., 30 fps), measures time from the application of infrared rays to the reception of reflected light in the unit of pixel, and acquires distance image data indicating a distance distribution of an environment around the operator cab31.

The depth sensor which applies infrared rays has recently been put to practical use as distance measuring means in increasing examples, and is utilized as an input interface for inputting a gesture in a game. Further, the construction machine1may be used during the night. Thus, the depth sensor using infrared rays is useful for the construction machine1. In the depth sensor which applies infrared rays, a system for measuring the time from the application of infrared rays to the reception of reflected light as described above is known as a time of flight (ToF) system. In addition, a structured light system which measures a distance from a light receiving pattern of reflected light when a specific pattern is applied is known as the depth sensor. The depth sensor of the structured light system may be employed. The construction machine1often operates outdoors. Thus, the depth sensor of a laser scanning ToF system which is resistant to interference with sunlight may be employed. Highly reliable and practical characteristics of the depth sensor which applies infrared rays achieve a stable detection operation of the distance sensor110.

Here, the depth sensor is used as the distance sensor110. However, the present invention is not limited thereto, and the distance sensor110may include a stereo camera which is cheaper than the depth sensor. In this case, the distance sensor110includes, for example, a stereo camera and a processor which calculates a distribution of the distance to an object from a plurality of pieces of image data captured by a plurality of cameras constituting the stereo camera. Low-cost, highly-reliable, and practical characteristics of the stereo camera achieve a stable detection operation of the distance sensor110.

The operation lever130is, for example, operated by the operator, and outputs a signal indicating the operation amount to the controller120.

The controller120includes, for example, a processor such as a microcontroller and a storage device which stores a program. The controller120includes a displacement detection unit121, a posture determination unit122, an interference prevention unit123, a storage unit124, and a position information acquisition unit125. Each of the displacement detection unit121, the posture determination unit122, the interference prevention unit123, the storage unit124, and the position information acquisition unit125may include a dedicated hardware circuit or may be implemented by executing a program by a CPU.

The displacement detection unit121has a function of detecting a displacement of the distance sensor110with respect to the operator cab31of the upper slewing body3.

The posture determination unit122compares posture information acquired by the acquisition unit100after initial setting with initial posture information stored in the storage unit124to determine that the boom15of the work attachment4has become an initial posture again.

The interference prevention unit123detects an interfering object which is the work attachment4or a held object held by the work attachment4using the distance image data acquired by the distance sensor110and determines the risk of interference of the detected interfering object with the operator cab31. Further, when the interference prevention unit123determines that there is a risk of interference, the interference prevention unit123performs at least one of notification of the risk and restriction of the operation of the construction machine1.

The storage unit124is capable of previously storing and outputting initial position information of the boom15, the initial position information being acquired by the position information acquisition unit125at initial setting (described below). Further, the storage unit124is capable of previously storing and outputting initial posture information of the boom15, the initial posture information being acquired by the acquisition unit100at the initial setting.

The position information acquisition unit125acquires position information (pixel data) of a specific part of the boom15with respect to the distance sensor110from the distance image data acquired by the distance sensor110.

InFIG. 3, the boom15, the arm16, and the attachment17are indicated by straight lines for simplifying description. In the example ofFIG. 3, in the coordinate system of the construction machine1, the front face31ais set at an origin point in the front-rear direction, a reference plane SE is set at an origin point in the up-down direction, and the center in the right-left direction of the front face31ais set at an origin point in the right-left direction.

The length of the boom15, the length of the arm16, and the length of the attachment17are known. Further, a distance do in the front-rear direction between the front face31aof the operator cab31and the angle sensor101is also known. Thus, when the rotation angle θ1of the boom15with respect to the front face31a, the rotation angle θ2of the arm16with respect to the boom15, and the rotation angle θ3of the attachment17with respect to the arm16are obtained, an altitude dy and a depth dz of a representative point P (e.g., the distal end P1of the attachment17, the distal end P2of the arm, the distal end P3of the boom) of the work attachment4can be calculated by using a trigonometric function. Here, the altitude dy indicates, for example, the distance in the up-down direction from the reference plane SE, which is parallel to the front-rear direction, to the point P, and the depth dz indicates, for example, the distance in the front-rear direction from the front face31ato the point P.

Thus, when the rotation angles θ1to θ3acquired by the acquisition unit100are obtained, the position of the point P in the three-dimensional coordinate system of the construction machine1, that is, in a real space can be identified. When the point P is obtained, it is possible to determine a coordinate area including the boom15, the arm16, and the attachment17in distance image data measured by the distance sensor110from the view angle, the attached position, and the angle of the optical axis of the distance sensor110. As a result, the position information acquisition unit125can acquire position information (pixel data) corresponding to the boom15from the distance image data acquired by the distance sensor110.

In the present embodiment, the position information acquisition unit125has correspondence information previously indicating a coordinate area where the boom15is located inside the distance image data in accordance with posture information acquired by the acquisition unit100. The position information acquisition unit125determines position information corresponding to the boom15in accordance with the posture information measured by the angle sensor of the acquisition unit100using the correspondence information.

For example, data of the rotation angle θ1of the boom15associated with a plurality of representative points on the outer edge of a coordinate area corresponding to the rotation angle θ1can be employed as the correspondence information. For example, the coordinates of a vertex of the coordinate area can be employed as the representative point. In the example of rectangular distance image data G401illustrated inFIG. 5, a coordinate area411indicates the boom15, but includes no vertex. In this case, for example, coordinates of three vertexes of the triangle coordinate area411included in the distance image data G401can be employed as the representative point. In particular, the position information acquisition unit125can acquired, as the position information of the boom15, data of a closest position closest to the distance sensor110(0401inFIG. 5) in the distance image data (coordinate area411) of the boom15included in the distance image data G401(the field of view of the distance sensor110) illustrated inFIG. 5. InFIG. 5, the coordinate areas412and413correspond to the arm16and the bucket17, respectively.

The interference prevention unit123detects an interfering object which is the work attachment4or a held object held by the work attachment4using the distance image data acquired by the distance sensor110and determines the risk of interference of the detected interfering object with the operator cab31. The interference prevention unit123determines the risk of interference by the interfering object according to whether the depth of the detected interfering object is located in the warning area D1or the automatic restriction area D2. Specifically, the interference prevention unit123may determine that the interfering object is located at coordinates having the smallest depth in the distance image data and detect the depth of the coordinates as the depth of the interfering object. Then, the interference prevention unit123may transform the height and depth of the detected interfering object from the three-dimensional coordinate system of the distance sensor110to the three-dimensional coordinate system of the construction machine1and determine whether the transformed height and depth are located in the warning area D1or the automatic restriction area D2.

Alternatively, the interference prevention unit123may determine whether the interfering object has entered the warning area D1and the automatic restriction area D2by using only the depth. In this case, the interference prevention unit123may transform the minimum depth in the distance image data to the three-dimensional coordinate system of the construction machine1, and determine that the interfering object has entered the automatic restriction area D2when the obtained depth is located within the range of the distance d12from the front face31aand determine that the interfering object has entered the warning area D1when the obtained depth is located within the range of the distance d12or more and the distance d11or less from the front face31a.

Further, when the interference prevention unit123determines that there is a risk of interference, the interference prevention unit123performs at least one of the warning to the operator and the restriction of the operation of the work attachment4. Specifically, when the interference prevention unit123determines that the interfering object is located in the warning area D1, the interference prevention unit123causes the notification unit140to give a warning. As a mode of the warning, a mode that sounds a buzzer, a mode that lights or flashes a warning lamp, or a mode that displays a warning message on a display panel can be employed. Alternatively, a mode of the combination of these modes may be employed as the mode of the warning. Further, when the interference prevention unit123determines that the interfering object is located in the automatic restriction area D2, the interference prevention unit123restricts the operation of the work attachment4by decelerating or automatically stopping the work attachment4.

In this case, the interference prevention unit123may decelerate the work attachment4by correcting the opening degree of the proportional valve of the control valve260, the opening degree being set by the valve adjustment unit126in accordance with the operation amount of the operation lever130, in a direction for decelerating the work attachment4. Further, in this case, the interference prevention unit123may increase a deceleration amount of the work attachment4as the depth of the interfering object approaches the operator cab31. The notification unit140is provided with a buzzer, a display panel, and a warning lamp which are disposed inside the operator cab31, and gives a warning to the operator under the control of the interference prevention unit123.

Next, a displacement determination process for the distance sensor110, the displacement determination process being executed by the displacement detection unit121according to the present embodiment, will be described in detail with reference toFIGS. 4 to 6.

Referring toFIG. 4, in a factory where the construction machine1is manufactured, predetermined initial setting is executed at the time of shipment. The display panel disposed inside the operator cab31is provided with a switch button for executing an initial setting mode. When the operator presses the switch button, the controller120starts the initial setting mode of the construction machine1(step S1ofFIG. 4). Then, the controller120displays an “initial setting posture” of the boom15on the display panel (step S2). Here, the initial setting posture is a posture of the boom15around the shaft, the posture being previously set so that the boom15is included in the field of view of the distance sensor110. The initial setting posture of the boom15, the initial setting posture being displayed on the display panel, includes the rotation angles θ1no θ3of the boom15, the arm16, and the bucket17, the rotation angles θ1to θ3being detected by the angle sensors101,102, and103, respectively. When the rotation angles θ1to θ3are set to previously set values, the posture of the work attachment4with respect to the upper slewing body3is fixed.

The operator operates the operation lever130while looking at the rotation angles θ1to θ3displayed on the display panel to bring the work attachment4, in particular, the boom15close to the initial setting posture (step S3). Then, the controller120determines whether the boom15has been detected by the distance sensor110(step S4). As described above, the position information acquisition unit125has correspondence information previously indicating a coordinate area where the boom15is located inside the distance image data of the distance sensor110in accordance with posture information acquired by the acquisition unit100. Thus, the controller120can determine whether the boom15has been detected by the distance sensor110using the correspondence information.

When the boom15has been detected by the distance sensor110(YES in step S4), the controller120determines the posture of the boom15at this time as the initial setting position (initial posture) (step S5). When the boom15has not been detected by the distance sensor110in step S4(NO in step S4), the controller120waits until the boom15is detected by a further operation of the boom15by the operator.

When the initial setting position is determined in step S5, the controller120stores an angle θi (initial posture information) of the boom15, the angle θi being detected by the first angle sensor101at this time, in the storage unit124(step S6). Further, the controller120controls the position information acquisition unit125to acquire initial position information of the boom15from distance image data acquired by the distance sensor110in the initial posture of the boom15. In the present embodiment, the initial position information corresponds to data (coordinates, distance data) of a closest position Mi closest to the distance sensor110in the distance image data of the boom15included in the field of view of the distance sensor110. InFIG. 5, corresponding to the boom15, data of the closest position P401in the triangle coordinate area411included in the distance image data (401is acquired by the position information acquisition unit125. The controller120stores the initial position information of the boom15, the initial position information being acquired by the position information acquisition unit125, in the storage unit124(step S6). As a result, the initial setting mode of the construction machine1is finished.

When the initial setting mode is finished, and the construction machine1shipped from the factory is installed in a used site, the displacement determination process is executed. In the present embodiment, the displacement determination process is continuously executed during the use of the construction machine1. Referring toFIG. 6, when the use of the construction machine1is started, the operator operates the operation lever130(FIG. 2) to rotate the boom15(step S11). At this time, the controller120controls the distance sensor110to acquire distance image data around the construction machine1and stores the acquired distance image data in the storage unit124(step S12). Since a storage capacity of the storage unit124is limited, the latest distance image data for a predetermined time (e.g., one minute) may be stored in the storage unit124.

When the boom15is operated, the posture determination unit122determines that the boom15has become the initial posture again before long (step S13). Specifically, the posture determination unit122compares the rotation angle θ1(posture information) of the boom15, the rotation angle θ1being acquired by the angle sensor101of the acquisition unit100, with the angle θi (initial posture information) stored in the storage unit124. Then, when θ1: θi is satisfied (YES in step S13), the posture determination unit122determines that the boom15has become the initial posture again. The position information acquisition unit125acquires comparative position information of the boom15from distance image data when θ1=θi is satisfied, the distance image data being stored in the storage unit124(step S14). In the present embodiment, in a manner similar to the initial position information at the initial setting, the comparative position information corresponds to data (coordinates, distance data) of a closest position Ms closest to the distance sensor110in the distance image data of the boom15included in the field of view of the distance sensor110.

The displacement detection unit121compares the comparative position information including data (coordinates, distance data) of the closest position Ms with the initial position information including data (coordinates, distance data) of the closest position Mi at the initial setting, the initial position information being stored in the storage unit124(step S15). Here, when the difference Δ between the comparative position information and the initial position information≤a (YES in step S16), the displacement detection unit121determines that there is no displacement in the distance sensor110fixed to the operator cab31. In this case, steps S11to S16are repeated while the use of the construction machine1is continued. A value of a threshold “a” compared in step S16is determined by a previously performed experiment and stored in the storage unit124.

On the other hand, when the difference Δ between the comparative position information and the initial position information>a (NO in step S16), the displacement detection unit121determines that there is a displacement in the distance sensor110fixed to the operator cab31. In this case, the displacement detection unit121causes the notification unit140to notify warning information of the displacement (step S17). When the operator corrects the displacement of the distance sensor110, the displacement detection process by the displacement detection unit121is finished.

As described above, according to the present embodiment, the displacement of the distance sensor110with respect to the operator cab31can be detected by comparing pieces of position information corresponding to the boom15in the distance image data acquired by the distance sensor110between the initial setting time and the time when the boom15becomes the initial posture again after the initial setting. In particular, the distance sensor110acquires the distance image data with the boom15as the second structure fixed at the initial posture. When the distance sensor110is displaced, position information of the boom15included in the distance image data is displaced. That is, when the distance sensor110is displaced in a direction away from the boom15from the position at the initial setting, the boom15is detected at a farther position than the position at the initial setting on the acquired position information. The displacement of the distance sensor110is detected using the difference. Further, data of the closest position Ms closest to the distance sensor110in the distance image data is acquired as the position information corresponding to the boom15. In the field of view of the distance sensor110(FIG. 5), the closest position Ms (P401ofFIG. 5) is an intersection point of the side edge of the boom15and the outer peripheral line of the distance image data. Thus, the closest position Ms is determined at a single point. Accordingly, a processing operation executed by the position information acquisition unit125to determine position information and a load are reduced. Thus, it is possible to easily and efficiently acquire the position information of the boom15from the distance image data.

Further, in the present embodiment, it is determined that the boom15has become the initial posture again after the shipment of the construction machine1on the basis of posture information of the boom15, the posture information being acquired by the acquisition unit100. Thus, it is possible to easily determine the timing when the displacement detection unit121checks the displacement of the distance sensor110. In other words, it is not necessary for the operator to adjust the posture of the boom15to the initial posture for a displacement detection operation. Further, in the present embodiment, it is possible to easily detect that the boom15has become the initial posture using the rotation angle θ1of the boom15, the rotation angle θ1being detected by the first angle sensor101. Further, in the present embodiment, it is possible to detect the displacement of the distance sensor110using the boom15included in the field of view of the distance sensor110. In particular, the boom15extends toward the front side away from the distance sensor110disposed on the operator cab31. Thus, the closest position of the boom15is easily uniquely determined in the field of view of the distance sensor110, and the displacement detection process for the distance sensor110is stably executed.

Further, in the present embodiment, the interference prevention unit123executes the interference prevention process operation for preventing the interference of the work attachment4or a held object with the operator cab31on the basis of the distance image data acquired by the distance sensor110. Thus, when the displacement of the distance sensor110occurs, false recognition of the distance sensor110occurs, and the interference prevention process operation is not correctly executed. Thus, the interference prevention process operation by the interference prevention unit123can be correctly executed by executing the displacement detection process for the distance sensor110as described above.

The construction machine1according to the embodiment of the present invention has been described above. Note that the present invention is not limited to these modes. Modifications as described below can be employed as the construction machine according to the present invention.

(1) The above embodiment describes a mode in which the position information acquisition unit125acquires, as position information, data of the closest position Ms closest to the distance sensor110in the distance image data of the boom15included in the field of view of the distance sensor110. However, the present invention is not limited thereto.FIG. 7is a diagram illustrating distance image data including the work attachment4(FIG. 1) including the boom15(second structure), the work attachment4being superimposed on a coordinate area G401of a construction machine in a modification of the present invention. In the present modification, the position information acquisition unit125(FIG. 2) acquires a side edge411(411G,411A) of a coordinate area411corresponding to the boom15as position information. That is, at initial setting, coordinates (initial position information) of the side edge411G of the boom15included in the distance image data are stored in the storage unit124. On the other hand, when the construction machine1is used, and the boom15is brought into the initial posture again, coordinates (initial position information) of the side edge411A of the boom15included in the distance image data are acquired. Also in this case, the displacement detection unit121(FIG. 2) can detect the displacement of the distance sensor110with respect to the operator cab31of the upper slewing body3by comparing the acquired comparative position information with the initial position information stored in the storage unit124.

(2) Further, the above embodiment describes a mode in which the upper slewing body3constitutes the first structure of the present invention, and the boom15of the work attachment4constitutes the second structure of the present invention. However, the present invention is not limited thereto. The second structure may be the entire work attachment4, or the arm16or the bucket17(holding attachment) may function as the second structure or may be included in the second structure. Further,FIG. 8Ais a plan view of a construction machine in a modification of the present invention. The present modification differs from the above embodiment mainly in that a lower traveling body2functions as the second structure of the present invention. Thus, the difference will be mainly described.FIG. 8Bis a plan view illustrating a state of an upper slewing body3slewed from a state illustrated inFIG. 8A.

The upper slewing body3slews with respect to the lower traveling body2around a shaft3A extending in the vertical direction. In other words, the lower traveling body2rotates relative to the upper slewing body3around the shaft3A. The shaft3A of the upper slewing body3and the lower traveling body2is provided with an angle sensor (not illustrated) which detects a rotation angle of the upper slewing body3. The posture of the upper slewing body3with respect to the lower traveling body2is detected by an output of the angle sensor. The upper slewing body3includes a work attachment4and an operator cab31. In a manner similar to the above embodiment, the operator cab31is provided with a distance sensor110. Further, in the present modification, a left distance sensor111is disposed on the left side part of the upper slewing body3, and a rear distance sensor112is disposed on the rear part of the upper slewing body3. Further, a right distance sensor113is disposed on the right side part of the upper slewing body3. The left distance sensor111, the rear distance sensor112, and the right distance sensor113detect that an operator or an obstacle is not present around the construction machine. As a result, it is possible to safely perform the operation of the construction machine. The construction machine may be provided with any of the left distance sensor111, the rear distance sensor112, and the right distance sensor113.

In the present modification, when the upper slewing body3slews as indicated by an arrow from a normal posture illustrated inFIG. 8A, the upper slewing body3is brought into a posture illustrated inFIG. 8B. The posture illustrated inFIG. 8Bcorresponds to an initial setting posture (initial posture) of the lower traveling body2in which initial setting of each sensor according to the present modification can be performed. In the normal posture illustrated inFIG. 8A, that is, the posture in which the front-rear direction of the upper slewing body3is aligned with the front-rear direction of the lower traveling body2, the lower traveling body2is not included in field of views of the left distance sensor111, the rear distance sensor112, and the right distance sensor113. On the other hand, in the initial posture illustrated inFIG. 8B, the left distance sensor111can detect a left target111G which is the left side part of the lower traveling body2. Similarly, the rear distance sensor112can detect a rear target112G which is the rear part of the lower traveling body2, and the right distance sensor113can detect a right target113G which is the right side part of the lower traveling body2. The left target111G, the rear target112G, and the right target113G are acquired as position information, and a displacement detection process similar to the displacement detection process of the above embodiment is executed. As a result, displacements of the left distance sensor111, the rear distance sensor112, and the right distance sensor113can be accurately detected. In this manner, in the present modification, the displacements of the distance sensors disposed on the upper slewing body3can be detected using the lower traveling body2included in the field of view (detection range) of each of the distance sensors. Note that the present modification is not limited to the above configuration, and a distance sensor (not illustrated) may be disposed on the front face part of the operator cab31. Also in this case, the lower traveling body2may be included in the field of view of the distance sensor in the initial setting posture (initial posture) of the lower traveling body2.

(3) Further, the above embodiment describes a mode in which the displacement detection unit121detects a displacement of the distance sensor110during the user of the construction machine1. However, the present invention is not limited thereto.FIG. 9is a flowchart illustrating a process during the user of a construction machine in a modification of the present invention. In the present modification, a displacement detection operation for the distance sensor110(FIG. 1) is executed with the intention of an operator during the use of the construction machine. Note that, also in the present modification, the initial setting ofFIG. 3is executed at the time of shipment of the construction machine from the factory.

The operator operates the display panel inside the operator cab31to execute a check mode of displacement detection (step S21). As a result, in a manner similar to the initial setting in the above embodiment, an “initial setting posture” of the boom15(FIG. 1) is displayed on the display panel (step S22). The operator operates the operation lever130(FIG. 2) while looking at the rotation angles θ1to θ3displayed on the display panel to bring the work attachment4, in particular, the boom15close to the initial setting posture (step S23).

When the boom15is brought into the initial setting posture by the operation by the operator, the position information acquisition unit125(FIG. 2) acquires comparative position information of the boom15from distance image data acquired by the distance sensor110(step S24).

The displacement detection unit121compares the comparative position information including data (coordinates, distance data) of the closest position Ms with the initial position information including data (coordinates, distance data) of the closest position Mi, the initial position information being stored in the storage unit124(step S25). When the difference Δ between the comparative position information and the initial position information≤a (YES in step S26), the displacement detection unit121determines that there is no displacement in the distance sensor110fixed to the operator cab31. In this case, the displacement detection unit121displays “OK display” on the display panel of the operator cab31(step S27).

On the other hand, when the difference Δ between the comparative position information and the initial position information>a (NO in step S26), the displacement detection unit121determines that there is a displacement in the distance sensor110fixed to the operator cab31. In this case, the displacement detection unit121causes the notification unit140to notify waning information of the displacement (step S28). When the displacement check mode by the displacement detection unit121is finished, the operator corrects the displacement of the distance sensor110. Thus, it is possible to stably detect and correct the displacement of the distance sensor110.

(4) Further, the above embodiment describes the hybrid excavator as the construction machine according to the present invention. However, the present invention is not limited thereto. The construction machine according to the present invention may be a crane, a demolition machine, an excavator, or a handling machine. Further, the construction machine may not include vertically separated vehicle bodies including the lower traveling body11and the upper slewing body12as illustrated inFIG. 1, but may include a single vehicle body.

(5) Further, the above embodiment describes the distance sensor as the detection unit of the present invention. However, the present invention is not limited thereto. A camera may be disposed as the detection unit on the upper slewing body3(first structure). Photographed data captured by the camera includes environment data indicating information (distance distribution) of an environment around the upper slewing body3. The position information acquisition unit125may acquire position information of a specific part of the boom15from the photographed data. Further, the camera may be a known distance image camera.