Work machine

Abstract

To provide a work machine which can precisely detect approach of an object to a work portion based on image data imaged by an imaging unit even when the work machine is used outdoors.SOLUTION: A work machine comprises: a work portion; a driving-motor which drives the work portion; an imaging unit which images an area in the vicinity of the work portion; and a controller. The work machine can be operated as a normal mode where the work machine works as usual or as a safety mode where the work machine works safer than the normal mode. The controller makes the work machine work as the safety mode when an object is determined to approach to the work portion based on the number of pixels within a prescribed range of color tones expressed in an HSV format among pixels contained in image data imaged by the imaging unit.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a work machine. [Background technology]

[0002] Patent Document 1 discloses a work machine including a working unit, a prime mover for driving the working unit, an imaging unit for imaging an area near the working unit, and a control unit. The work machine can operate in a normal mode in which it operates normally, and a safety mode in which it operates safer than the normal mode. The control unit is configured to operate the work machine in the safety mode when it is determined that an object is approaching the work unit based on the number of pixels having a designated color value when expressed in YUV format among pixels included in image data captured by the imaging unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-23186 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a work machine is used outdoors, image data may be captured in a bright environment or in a dark environment. When image data is expressed in YUV or RGB format, even when an object of the same color is captured, the color values ​​may differ depending on the brightness at the time of capture. For this reason, when a work machine is used outdoors, it may be difficult to accurately detect the approach of an object such as a user's body to a working unit. This specification provides a technology that can accurately detect the approach of an object to a working unit based on image data captured by an imaging unit, even when a work machine is used outdoors. [Means for solving the problem]

[0005] The working machine disclosed in this specification may include a working unit, a prime mover for driving the working unit, an imaging unit for imaging an area near the working unit, and a control unit. The working machine may be operable in a normal mode in which it operates normally, and a safety mode in which it operates safer than the normal mode. The control unit may be configured to operate the working machine in the safety mode when it is determined that an object is approaching the working unit based on the number of pixels that have a hue within a predetermined range when expressed in HSV format among pixels included in image data captured by the imaging unit.

[0006] When the image data captured by the imaging unit is expressed in the HSV format of hue, saturation, and value, objects of the same color will have the same hue even if the brightness at the time of capturing the image differs. Therefore, according to the above configuration, even when the work machine is used outdoors, it is possible to accurately detect that an object is approaching the working unit based on the image data captured by the imaging unit. [Brief description of the drawings]

[0007] [Figure 1] 1 is a block diagram showing a schematic configuration of a work machine 2 according to an embodiment. [Diagram 2] 2 is a perspective view of a working unit 8 of a working machine 2 according to the embodiment, as viewed from above on the front right. [Diagram 3] 1 is a vertical cross-sectional view of a working unit 8 of a working machine 2 according to an embodiment in a state where a movable blade 34 is open relative to a fixed blade 32. FIG. [Figure 4] 2 is a perspective view of the internal structure of a working unit 8 of a working machine 2 according to the embodiment, as viewed from above on the front right. [Diagram 5] 2 is a vertical cross-sectional view of a working unit 8 of a working machine 2 according to the embodiment in a state where a movable blade 34 is closed relative to a fixed blade 32. FIG. [Figure 6] 2 is a perspective view of a working unit 8 of a working machine 2 according to the embodiment, as viewed from above on the front left. [Figure 7]1 is a perspective view seen from above and behind showing a state in which a branch 82 is being cut using the working machine 2 according to the embodiment. FIG. [Figure 8] 4 is a flowchart of an approach determination process performed by a control unit 14 of a work machine 2 according to the embodiment. [Figure 9] 13 is an example of image data ID captured by the camera 74 when the camera 74 is not blocked in the work machine 2 according to the embodiment. [Figure 10] 13 is an example of image data ID captured by the camera 74 when the camera 74 is blocked by an obstacle 84 in the work machine 2 according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Representative and non-limiting examples of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing the preferred examples of the present invention, and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or in conjunction with other features and inventions to provide further improved work machines and methods of using and manufacturing the same.

[0009] In addition, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, but are specifically described only to illustrate representative embodiments of the present invention. Furthermore, the various features of the following representative embodiments and the various features described in the claims do not have to be combined in the exact manner of the embodiments described herein or in the order listed in order to provide additional and useful embodiments of the present invention.

[0010] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, the control unit may be configured to determine whether or not the object is approaching the working unit based on the number of pixels included in the image data captured by the imaging unit, the hue of which is within the predetermined range and the saturation of which when expressed in HSV format is equal to or greater than a threshold value.

[0012] When the image data captured by the imaging unit is expressed in HSV format, the hue of a low-saturation color such as white, black, or gray may have the same value as the hue of another high-saturation color (e.g., purple). Therefore, if an attempt is made to determine whether a pixel corresponds to an object based only on the hue of the pixel, a pixel in which a low-saturation color is reflected may be erroneously determined to be a pixel corresponding to the object. According to the above configuration, whether an object is approaching the working unit is determined based on the number of pixels whose hue is within a predetermined range and whose saturation is equal to or greater than a threshold value, so that erroneous detection due to reflection of a low-saturation color can be suppressed.

[0013] In one or more embodiments, the control unit may set the threshold value to a lower value as the brightness of a pixel contained in the image data captured by the imaging unit when expressed in HSV format becomes higher.

[0014] In general, when image data is captured in a bright environment, the saturation of pixels corresponding to an object tends to be low, whereas when image data is captured in a dark environment, the saturation of pixels corresponding to an object tends to be high. According to the above configuration, the higher the brightness of a pixel included in the image data, the lower the saturation threshold is set, so that the approach of an object to the working unit can be detected more reliably.

[0015] In one or more embodiments, the predetermined range may be a range between 230° and 360°.

[0016] When using a work machine outdoors, the blue of the sky, the green of leaves and grass, and the brown of tree branches and trunks may appear in the image data captured by the imaging unit. The hues of these colors are in the range of 0° to 230°, and colors with hues in the range of 230° to 360° (e.g. purple) rarely appear in the image data. According to the above configuration, by setting the hue of the color of the target object in the range of 230° to 360°, it is possible to accurately detect that the target object is approaching the working unit.

[0017] In one or more embodiments, the working machine may further include a housing that supports the working unit and the imaging unit and is held by a user. The working unit may include a fixed blade and a movable blade that is rotatable about a rotation axis that extends in the left-right direction relative to the fixed blade and is driven by the prime mover.

[0018] The above-mentioned working machine functions as pruning scissors for cutting branches and the like. When cutting branches using the above-mentioned working machine, a user may perform the work while holding the housing with one hand and holding the branch with the other hand. According to the above-mentioned configuration, by wearing a glove of a color (e.g., purple) whose hue falls within a predetermined range on the other hand, the working machine can be operated in a safety mode when the glove, which is an object, approaches the working unit. This ensures the safety of the user.

[0019] In one or more embodiments, the imaging unit may be disposed on an upper surface side of the housing.

[0020] In a configuration in which the working unit has a fixed blade and a movable blade, if the imaging unit is located on the right side (or left side) of the housing, the area to the right (or left) of the working unit is within the field of view of the imaging unit, but the area to the left (or right) of the working unit is blocked by the working unit and does not enter the field of view of the imaging unit, making it difficult to image the areas on both the left and right sides of the working unit. Furthermore, if the imaging unit is located on the bottom side of the housing, the areas on both the left and right sides of the working unit can be imaged, but the imaging unit protrudes downward from the housing and is likely to get in the way of work. According to the above configuration, since the imaging unit is located on the top side of the housing, it is possible to image the areas on both the left and right sides of the working unit. Furthermore, it is possible to prevent the imaging unit from protruding downward from the housing and getting in the way of work.

[0021] In one or more embodiments, when the movable blade is in its maximum open state relative to the fixed blade and the longitudinal direction of the housing is horizontal, the imaging unit may be positioned below an upper end of the movable blade.

[0022] By arranging the imaging unit on the upper surface side of the housing, even if the imaging unit protrudes upward from the housing, it is unlikely to get in the way of work as long as the imaging unit is arranged below the upper end of the movable blade when the movable blade is in the fully opened state. With the above configuration, even if the imaging unit protrudes upward from the housing, it is possible to prevent the imaging unit from getting in the way of work.

[0023] In one or more embodiments, the device may further include an illumination portion supported by the housing and configured to illuminate an area adjacent the working portion.

[0024] According to the above configuration, even in a dark environment, image data can be captured with the illumination unit illuminating the area near the working unit, so that image data can be acquired under the same conditions as when image data is captured in a bright environment, thereby suppressing variations in detection accuracy due to differences in environmental brightness.

[0025] In one or more embodiments, the lighting section may include a right lighting section disposed on a right side of the housing and a left lighting section disposed on a left side of the housing.

[0026] In a configuration in which the working unit has a fixed blade and a movable blade, if the working machine is equipped with only a right-side lighting unit (or a left-side lighting unit), the area on the right-side (or left-side) of the working unit will be illuminated, but the area on the left-side (or right-side) of the working unit will not be illuminated, making it difficult to illuminate both the left and right areas of the working unit. According to the above configuration, the working machine is equipped with both a right-side lighting unit and a left-side lighting unit, so it is possible to properly illuminate both the left and right areas of the working unit.

[0027] In one or more embodiments, the control unit may identify, among the pixels included in the image data, a first pixel located at a position corresponding to the fixed blade and a second pixel located at a position not corresponding to the fixed blade or the movable blade, and may determine whether or not the imaging unit is obstructed by an obstacle based on the hue, saturation and / or brightness of the first pixel and the second pixel when expressed in HSV format.

[0028] When the imaging unit is not covered by an obstacle, the first pixel arranged at a position corresponding to the fixed blade always reflects the same color (i.e., the color of the fixed blade), and the second pixel arranged at a position not corresponding to the fixed blade or the movable blade reflects the color of the background. In this case, the first pixel and the second pixel have different values ​​of hue, saturation, and brightness. In contrast, when the imaging unit is covered by an obstacle, the same color of the obstacle is reflected in the first pixel arranged at a position corresponding to the fixed blade and in the second pixel arranged at a position not corresponding to the fixed blade or the movable blade. In this case, the first pixel and the second pixel have approximately the same values ​​of hue, saturation, and brightness. According to the above configuration, it is possible to appropriately determine whether the imaging unit is covered by an obstacle based on the hue, saturation, and / or brightness of the first pixel arranged at a position corresponding to the fixed blade and the second pixel arranged at a position not corresponding to the fixed blade or the movable blade.

[0029] In one or more embodiments, the imaging unit may have a horizontal angle of view in the range of 60° to 120°.

[0030] If the horizontal angle of view is too wide, the object will be captured in the image data even if it is not very close to the work area in the horizontal direction. Conversely, if the horizontal angle of view is too narrow, the object will not be captured in the image data until it is quite close to the work area in the horizontal direction. With the above configuration, it is possible to appropriately detect whether the object is approaching the work area in the horizontal direction.

[0031] In one or more embodiments, the imaging unit may have a vertical angle of view in the range of 45° to 90°.

[0032] If the vertical angle of view is too wide, the object will be captured in the image data even if the object is not very close to the work unit in the vertical direction. Conversely, if the vertical angle of view is too narrow, the object will not be captured in the image data until the object is quite close to the work unit in the vertical direction. With the above configuration, it is possible to appropriately detect whether the object is approaching the work unit in the vertical direction.

[0033] In one or more embodiments, the shutter speed of the imaging unit may be in the range of 0.1 ms to 2 ms.

[0034] According to the above configuration, when the work machine is used outdoors, image data can be captured at an appropriate brightness.

[0035] In one or more embodiments, the safety modes may include a first safety mode that operates safer than the normal mode, and a second safety mode that operates safer than the first safety mode. The control unit may be configured to operate the work machine in the first safety mode when it is determined that the object is approaching the working unit at a first approach level based on the number of pixels whose hue is within the predetermined range among pixels included in the image data captured by the imaging unit. The control unit may be configured to operate the work machine in the second safety mode when it is determined that the object is approaching the working unit at a second approach level closer than the first approach level based on the number of pixels whose hue is within the predetermined range among pixels included in the image data captured by the imaging unit.

[0036] According to the above configuration, the work machine can be operated in a stepwise safer mode depending on the approach level of the object to the working unit.

[0037] (Example) As shown in FIG. 1, the working machine 2 includes a battery unit 4, a switch unit 6, and a working unit 8. The working machine 2 is, for example, a pair of pruning scissors used for cutting stems and branches of flowers, trees, etc. The battery unit 4 includes a shoulder belt and a waist belt, and is attached to a harness (not shown) worn by a user. The switch unit 6 is attached to the waist belt of the harness. The working unit 8 is used by the user by holding it with one hand. The battery unit 4 and the switch unit 6 are electrically connected via a cable 10. The switch unit 6 and the working unit 8 are electrically connected via a connection cord 12.

[0038] The battery unit 4 includes a control unit 14 and a battery pack 16. The control unit 14 includes a CPU, ROM, RAM, etc., and controls the operation of the work machine 2. The battery pack 16 is detachably attached to the battery unit 4. The battery pack 16 includes a secondary battery such as a lithium ion battery. The work machine 2 operates using power supplied from the battery pack 16.

[0039] The switch unit 6 includes a main power switch 18, an indicator lamp 20, and a buzzer 22. The main power switch 18 accepts an operation from a user to switch the main power of the work machine 2 on / off. The indicator lamp 20 displays to the user of the work machine 2 the on / off state of the main power and the presence or absence of an abnormality. The buzzer 22 issues a warning sound to the user of the work machine 2.

[0040] As shown in FIG. 2, the working unit 8 includes a housing 24. The housing 24 has a longitudinal direction in the front-rear direction. The housing 24 is formed with a grip 26 that the user holds with one hand. The rear end of the housing 24 is provided with a connector 27 to which the connection cord 12 is attached and detached. A trigger 28 that can be operated by the user and a guard 30 that protects the user's fingers operating the trigger 28 are provided in front of the grip 26 of the housing 24. The trigger 28 and the guard 30 are provided on the underside of the housing 24. A fixed blade 32 and a movable blade 34 that rotates relative to the fixed blade 32 are provided at the front end of the housing 24. The movable blade 34 is disposed adjacent to the right side of the fixed blade 32.

[0041] As shown in Fig. 3, an electric motor 36, a power transmission unit 38, and a trigger position detection unit 40 are accommodated inside the housing 24. The electric motor 36 is, for example, a DC brushless motor, such as a coreless motor. The electric motor 36 is disposed inside the grip 26. An output shaft 42 of the electric motor 36 extends forward.

[0042] The power transmission unit 38 includes a reduction gear mechanism 44, a screw shaft 46, a nut 48, a nut casing 50, and a link arm 52. The reduction gear mechanism 44 is, for example, a planetary gear mechanism, and transmits the rotation of the output shaft 42 to the screw shaft 46 after reducing the speed. The screw shaft 46 and the nut 48 form a so-called ball screw mechanism. The nut 48 is fixed to the nut casing 50. When the screw shaft 46 rotates forward, the nut 48 and the nut casing 50 move backward relative to the housing 24. When the screw shaft 46 rotates backward, the nut 48 and the nut casing 50 move forward relative to the housing 24.

[0043] The fixed blade 32 includes a lower blade portion 54 and a support portion 56. The support portion 56 is fixed to the housing 24. The movable blade 34 includes an upper blade portion 58 and a lever portion 60. The movable blade 34 is rotatably connected to the fixed blade 32 via a bolt 62 extending in the left-right direction.

[0044] As shown in FIG. 4, the link arm 52 extends in the front-rear direction. The rear end of the link arm 52 is rotatably connected to the nut 48 via a pin 64 extending in the left-right direction. The front end of the link arm 52 is rotatably connected to the lever portion 60 via a pin 66 extending in the left-right direction. As shown in FIG. 5, when the nut 48 and the nut casing 50 move rearward, the lower end of the lever portion 60 moves rearward, and the movable blade 34 rotates clockwise in FIG. 5 around the bolt 62 as a rotation axis. As a result, the movable blade 34 is closed relative to the fixed blade 32, and the cutting operation is performed by the upper blade portion 58 and the lower blade portion 54. Conversely, as shown in FIG. 3, when the nut 48 and the nut casing 50 move forward, the lower end of the lever portion 60 moves forward, and the movable blade 34 rotates counterclockwise in FIG. 3 around the bolt 62 as a rotation axis. As a result, the movable blade 34 opens relative to the fixed blade 32.

[0045] 4, the trigger 28 is rotatably connected to the nut 48 via a pin 64. As the nut 48 moves in the front-rear direction, the trigger 28 also moves in the front-rear direction. When the user pulls in the trigger 28, the trigger 28 rotates relative to the nut 48 with the pin 64 as a rotation axis.

[0046] As shown in FIG. 3, the trigger position detection unit 40 includes a magnet 68, a spring 70, and a trigger position sensor 72 (see FIG. 4). The magnet 68 is arranged to have an N pole on the front side (or rear side) and an S pole on the rear side (or front side). The magnet 68 is supported on the nut casing 50 so as to be movable in the front-rear direction. The spring 70 biases the magnet 68 forward with respect to the nut casing 50. The front end of the magnet 68 abuts against the rear surface of the trigger 28. The trigger position sensor 72 shown in FIG. 4 includes, for example, a Hall element. The trigger position sensor 72 is fixed to the nut casing 50. The trigger position sensor 72 detects the retracted position of the trigger 28 by detecting the position of the magnet 68 (see FIG. 3) in the front-rear direction with respect to the nut casing 50.

[0047] The control unit 14 shown in FIG. 1 rotates the electric motor 36 in the forward or reverse direction in response to a detection signal from the trigger position sensor 72. When the trigger 28 is pulled in, the magnet 68 moves rearward from the neutral position relative to the nut casing 50, and the control unit 14 rotates the electric motor 36 in the forward direction accordingly. This causes the movable blade 34 to rotate in a direction in which the movable blade 34 closes relative to the fixed blade 32. Conversely, when the pulling operation of the trigger 28 is released, the magnet 68 moves forward from the neutral position relative to the nut casing 50, and the control unit 14 rotates the electric motor 36 in the reverse direction accordingly. This causes the movable blade 34 to rotate in a direction in which the movable blade 34 opens relative to the fixed blade 32.

[0048] As shown in Fig. 6, the housing 24 is provided with a camera 74, a right light 76, and a left light 78. The camera 74 is provided on the upper surface side of the front part of the housing 24. The right light 76 is provided on the right surface side of the front part of the housing 24. The left light 78 is provided on the left surface side of the front part of the housing 24. The right light 76 and the left light 78 are each disposed facing forward, and illuminate the areas near the fixed blade 32 and the movable blade 34.

[0049] The camera 74 is disposed facing forward and captures an area near the fixed blade 32 and the movable blade 34. Image data captured by the camera 74 is sent to the control unit 14 (see FIG. 1). As shown in FIG. 3, the optical axis OX of the camera 74 is disposed so as to face diagonally downward in the vertical direction, for example, 12° downward with respect to the horizontal direction. The vertical angle of view θ1 of the camera 74 is, for example, within a range of 45° to 90°, for example, 50°. In this case, the entire lower blade portion 54 can be included in the field of view of the camera 74. As shown in FIG. 7, the optical axis OX of the camera 74 is disposed so as to face forward in the horizontal direction. The horizontal angle of view θ2 of the camera 74 is, for example, within a range of 60° to 120°, for example, 65°. The focal length of the camera 74 is, for example, 50 mm to 100 mm. The resolution of the camera 74 is, for example, QVGA (320×240 pixels) or more, for example, VGA (640×480 pixels). The frame rate of the camera 74 is, for example, 30 FPS or more. The shutter speed of the camera 74 is, for example, within a range of 0.1 ms to 2 ms, for example, 1 ms.

[0050] 7, a user uses the work machine 2 while holding the grip 26 of the working unit 8 with one hand and wearing a purple glove 80 with the other hand. For example, the user cuts a branch 82 with the working unit 8 held in one hand while holding a branch 82 with the other hand wearing the glove 80.

[0051] When the work implement 2 is a pair of pruning shears, during normal work, the image data from the camera 74 captures the green of leaves and the blue of the sky, but rarely captures purple objects. For this reason, by using the purple gloves 80, it is easier to distinguish between colors captured during normal work.

[0052] The color captured by the camera 74 can be determined based on the hue when each pixel included in the image data is expressed in the HSV format using hue, saturation, and value. For example, the brown of dead leaves and tree branches has a hue in the range of 15° to 60°, the green of leaves has a hue in the range of 80° to 150°, and the blue of the sky has a hue in the range of 180° to 225°. In contrast, the purple of the glove 80 has a hue in the range of 270° to 300°. Therefore, based on the hue of a pixel included in the image data, it can be determined whether the pixel corresponds to the glove 80 or something else.

[0053] (Approach determination process) When it is determined based on image data from the camera 74 that the glove 80 is approaching the fixed blade 32 and the movable blade 34, the control unit 14 operates the work machine 2 in a safety mode that operates safer than the normal mode. This ensures the safety of the user. The approach determination process performed by the control unit 14 will be described below with reference to FIG. 8.

[0054] In S2, the control unit 14 acquires image data from the camera 74. The image data is expressed in HSV format, and indicates the hue, saturation, and brightness of each pixel included in the image data.

[0055] In S4, the control unit 14 judges whether the camera 74 is blocked based on the image data. As shown in FIG. 9, when the camera 74 is not blocked, the image data ID includes the fixed blade 32, the movable blade 34, and the background. At this time, the fixed blade 32 does not move relative to the camera 74, so the fixed blade 32 is always reflected in the pixel P1 arranged at a position corresponding to the fixed blade 32. On the other hand, the pixel P2 arranged at a position not corresponding to the fixed blade 32 and the movable blade 34 includes leaves, branches, etc. in the background. For this reason, the hue, saturation, and brightness of the pixel P1 and the pixel P2 are different. On the other hand, when the camera 74 is blocked by an obstacle 84, as shown in FIG. 10, the image data does not include the fixed blade 32, the movable blade 34, or leaves, branches, etc. in the background, and the same obstacle 84 is reflected in almost all pixels. In this case, pixel P1 arranged at a position corresponding to fixed blade 32 has similar hue, saturation, and brightness, and pixel P2 arranged at a position not corresponding to fixed blade 32 or movable blade 34. Therefore, in S4 of Fig. 8, control unit 14 compares the hue, saturation, and brightness of pixel P1 and pixel P2, respectively, and determines that camera 74 is blocked by obstacle 84 if the respective differences are within 20%.

[0056] If it is determined in S4 that the camera 74 is blocked (YES), the process proceeds to S6. In S6, the control unit 14 brings the work machine 2 to an abnormal stop. Specifically, the control unit 14 prohibits the rotation of the electric motor 36, displays the occurrence of an abnormality on the indicator lamp 20, and generates an alarm sound from the buzzer 22 to notify the user that the camera 74 is blocked. After S6, the process in FIG. 8 ends.

[0057] If it is determined in S4 that the camera 74 is not obstructed (NO), the process proceeds to S8. In S8, the control unit 14 calculates the average brightness value of all pixels in the image data.

[0058] In S10, the control unit 14 sets the saturation threshold value based on the average brightness value calculated in S8. For example, when the average brightness value is equal to or greater than a first reference value (e.g., 80%), the control unit 14 sets the saturation threshold value to a first threshold value (e.g., 30%), when the average brightness value is equal to or greater than a second reference value (e.g., 50%) that is lower than the first reference value, the control unit 14 sets the saturation threshold value to a second threshold value (e.g., 50%) that is higher than the first threshold value, and when the average brightness value is less than the second reference value, the control unit 14 sets the saturation threshold value to a third threshold value (e.g., 70%) that is higher than the second threshold value.

[0059] In S12, the control unit 14 selects a determination target pixel from among the pixels included in the image data for which the determination processes in S14-S20 have not yet been performed.

[0060] In S14, the control unit 14 determines whether the hue of the determination target pixel is within a predetermined range (for example, a range of 230° to 360°, for example, a range of 235° to 320°). If the hue of the determination target pixel is within the predetermined range (YES), the process proceeds to S16.

[0061] In S16, the control unit 14 judges whether the saturation of the pixel to be judged is equal to or greater than the saturation threshold value set in S10. When the image data is in the HSV format, the hue of a low saturation color such as white, gray, or black may have the same value as the hue of another color with high saturation (e.g., purple). Therefore, in this embodiment, if the saturation of the pixel to be judged is below the threshold value, it is judged to be a white, gray, or black pixel, and not a purple pixel corresponding to the glove 80, and if the saturation of the pixel to be judged is equal to or greater than the threshold value, it is judged to be a purple pixel corresponding to the glove 80.

[0062] In addition, in image data captured in a bright environment, the saturation of pixels in which the purple gloves 80 are reflected tends to be low, and in image data captured in a dark environment, the saturation of pixels in which the purple gloves 80 are reflected tends to be high. For this reason, in the process of S10 in this embodiment, the higher the average brightness of the pixels included in the image data, the lower the saturation threshold is set, and the lower the average brightness of the pixels included in the image data, the higher the saturation threshold is set. This makes it possible to more effectively suppress false detections due to the reflection of low-saturation colors.

[0063] In S16, if the saturation of the determination target pixel is equal to or greater than the saturation threshold value (YES), the process proceeds to S18. In S18, the control unit 14 determines that the determination target pixel is a pixel corresponding to the glove 80. After S18, the process proceeds to S22.

[0064] In S14, if the hue of the pixel to be determined is not within the predetermined range (if NO), and in S16, if the saturation of the pixel to be determined is below the threshold (if NO), the process proceeds to S20. In S20, the control unit 14 determines that the pixel to be determined is not a pixel corresponding to the glove 80. After S20, the process proceeds to S22.

[0065] In S22, the control unit 14 judges whether the judgment process of S14-S20 is completed for all pixels included in the image data. If the judgment process is not completed for all pixels (if NO), the process returns to S12. If the judgment process is completed for all pixels (if YES), the process proceeds to S24.

[0066] In S24, the control unit 14 specifies the approach level of the glove 80 with respect to the fixed blade 32 and the movable blade 34 based on the number of pixels determined to correspond to the glove 80 among the pixels included in the image data. For example, when the control unit 14 sets the number of all pixels included in the image data as N0 and the number of pixels corresponding to the glove 80 as N1, if the ratio N1 / N0 is less than a first predetermined value (e.g., 3%), the approach level is specified as level 0; if the ratio N1 / N0 is equal to or greater than the first predetermined value (e.g., 3%) and less than a second predetermined value (e.g., 5%), the approach level is specified as level 1; and if the ratio N1 / N0 is equal to or greater than the second predetermined value (e.g., 5%), the approach level is specified as level 2.

[0067] Alternatively, the control unit 14 may cut out the portion including the fixed blade 32 and the movable blade 34 from the image data as first partial image data, set the number of all pixels included in the first partial image data as M0, and when the number of pixels corresponding to the glove 80 in the first partial image data is M1, if the ratio M1 / M0 is equal to or greater than a predetermined value (e.g., 4%), specify the approach level as level 1. Further, the control unit 14 may cut out a smaller portion including the fixed blade 32 and the movable blade 34 from the image data as second partial image data, set the number of all pixels included in the second partial image data as L0 (L0 < M0), and when the number of pixels corresponding to the glove 80 in the second partial image data is L1, if the ratio L1 / L0 is equal to or greater than a predetermined value (e.g., 4%), specify the approach level as level 2. Additionally, when the approach level does not correspond to either level 1 or level 2, the control unit 14 may specify the approach level as level 0.

[0068] In S26, the control unit 14 determines whether the approach level is level 2. If the approach level is level 2 (YES), the process proceeds to S28. In S28, the control unit 14 prohibits the rotation of the electric motor 36, displays the occurrence of an abnormality on the display lamp 20, generates a warning sound with the buzzer 22, and notifies the user that the glove 80 is approaching the fixed blade 32 and the movable blade 34 excessively. After S28, the process of FIG. 8 ends.

[0069] If the approach level is not level 2 in S26 (if NO), the process proceeds to S30. In S30, the control unit 14 determines whether the approach level is level 1. If the approach level is level 1 (if YES), the process proceeds to S32. In S32, the control unit 14 displays a warning on the indicator lamp 20 and generates a warning sound from the buzzer 22 to notify the user that the glove 80 is approaching the fixed blade 32 and the movable blade 34. Note that in S32, the electric motor 36 is permitted to rotate, and the user can continue working using the work machine 2. After S32, the process returns to S2.

[0070] If the approach level is not level 1 (NO in S30), that is, if the approach level is level 0, the process returns to S2.

[0071] Through the processing of S24-S32, when the approach level is level 0, the work machine 2 operates normally. That is, it can be said that when the approach level is level 0, the work machine 2 operates in the normal mode. Furthermore, when the approach level is level 1, the work machine 2 operates safer than in the normal mode. That is, it can be said that when the approach level is level 1, the work machine 2 operates in a first safety mode that is safer than the normal mode. Furthermore, when the approach level is level 2, the work machine 2 operates safer than in the first safety mode. That is, it can be said that when the approach level is level 2, the work machine 2 operates in a second safety mode that is safer than the first safety mode.

[0072] (Modification) In the above-described work machine 2, the battery unit 4 and the switch unit 6 may be mounted on the working unit 8. In this case, a battery attachment portion (not shown) for attaching and detaching the battery pack 16, a main power switch 18, and an indicator lamp 20 may be provided on the outer surface of the housing 24 of the working unit 8. In addition, the control unit 14 and a buzzer 22 may be housed inside the housing 24 of the working unit 8.

[0073] In the above-described working machine 2, the predetermined range of hues may be any range as long as it includes the hue of the color of the object. In addition, the color of the object is not limited to purple and may be another color.

[0074] The working machine 2 may be another type of working machine, such as a reciprocating saw or a rebar binding machine. For example, if the working machine 2 is a reciprocating saw, the reciprocating saw blade and the like correspond to the working part. If the working machine 2 is a rebar binding machine, the working part includes a curl guide that feeds wire around the rebar, a hook that twists the wire wound around the rebar, and the like.

[0075] (Correspondence) As described above, in one or more embodiments, the work machine 2 includes the fixed blade 32 and the movable blade 34 (an example of a working unit), the electric motor 36 (an example of a prime mover) that drives the movable blade 34, the camera 74 (an example of an imaging unit) that captures an image of the area near the fixed blade 32 and the movable blade 34, and the control unit 14. The work machine 2 can operate in a normal mode in which it operates normally, and a safety mode in which it operates safer than the normal mode. The control unit 14 is configured to operate the work machine 2 in the safety mode when it is determined that the glove 80 (an example of an object) is approaching the fixed blade 32 and the movable blade 34 based on the number of pixels whose hues, when expressed in HSV format, are within a predetermined range among the pixels included in the image data captured by the camera 74.

[0076] When image data captured by camera 74 is expressed in HSV format, objects of the same color have the same hue even if the brightness at the time of capturing the image is different. Therefore, according to the above configuration, even when work machine 2 is used outdoors, it is possible to accurately detect the approach of glove 80 to fixed blade 32 and movable blade 34 based on image data captured by camera 74.

[0077] In one or more embodiments, the control unit 14 is configured to determine whether the glove 80 is approaching the fixed blade 32 and the movable blade 34 based on the number of pixels contained in the image data captured by the camera 74 that have a hue within a predetermined range and a saturation equal to or greater than a threshold value when expressed in HSV format.

[0078] When the image data captured by the camera 74 is expressed in the HSV format, the hue of a low-saturation color such as white, black, or gray may have the same value as the hue of another high-saturation color (e.g., purple). For this reason, if an attempt is made to determine whether or not a pixel corresponds to the glove 80 based only on the hue of the pixel, a pixel in which a low-saturation color is reflected may be erroneously determined to correspond to the glove 80. According to the above configuration, whether or not the glove 80 is approaching the fixed blade 32 and the movable blade 34 is determined based on the number of pixels whose hue is within a predetermined range and whose saturation is equal to or greater than a threshold value, so that erroneous detection due to the reflection of a low-saturation color can be suppressed.

[0079] In one or more embodiments, the control unit 14 sets the saturation threshold to a lower value as the brightness of a pixel included in image data captured by the camera 74 increases when expressed in HSV format.

[0080] In general, when image data is captured in a bright environment, the saturation of pixels corresponding to the purple gloves 80 tends to be low, and when image data is captured in a dark environment, the saturation of pixels corresponding to the purple gloves 80 tends to be high. According to the above configuration, the higher the brightness of the pixels included in the image data, the lower the saturation threshold value is set, so that the approach of the gloves 80 to the fixed blade 32 and the movable blade 34 can be detected more reliably.

[0081] In one or more embodiments, the predetermined range of hues may be a range of 230° to 360°.

[0082] When the work machine 2 is used outdoors, the blue of the sky, the green of leaves and grass, and the brown of tree branches and trunks may appear in the image data captured by the camera 74. The hues of these colors are in the range of 0° to 230°, and colors with hues in the range of 230° to 360° (e.g., purple) rarely appear in the image data. According to the above configuration, by setting the hue of the color of the glove 80 to be in the range of 230° to 360°, it is possible to accurately detect the approach of the glove 80 to the fixed blade 32 and the movable blade 34.

[0083] In one or more embodiments, the work machine 2 further includes a housing 24 that supports the fixed blade 32, the movable blade 34, and the camera 74 and is held by a user. The movable blade 34 is rotatable about a rotation axis that extends in the left-right direction relative to the fixed blade 32, and is driven by an electric motor 36.

[0084] The above-mentioned working machine 2 functions as pruning scissors for cutting branches 82 and the like. When cutting branches 82 using the above-mentioned working machine 2, the user may perform the work while holding the housing 24 with one hand and holding the branch 82 with the other hand. According to the above-mentioned configuration, by wearing a glove 80 of a color (e.g., purple) whose hue falls within a predetermined range on the other hand, the working machine 2 can be operated in a safety mode when the glove 80 approaches the fixed blade 32 and the movable blade 34. This ensures the safety of the user.

[0085] In one or more embodiments, the camera 74 is located on the top side of the housing 24 .

[0086] In a configuration in which the work machine 2 includes the fixed blade 32 and the movable blade 34, if the camera 74 is located on the right side (or left side) of the housing 24, the area to the right (or left) of the fixed blade 32 and the movable blade 34 is within the field of view of the camera 74, but the area to the left (or right) of the fixed blade 32 and the movable blade 34 is blocked by the fixed blade 32 and the movable blade 34 and does not enter the field of view of the camera 74, making it difficult to image the areas on both the left and right sides of the fixed blade 32 and the movable blade 34. Furthermore, if the camera 74 is located on the lower side of the housing 24, the areas on both the left and right sides of the fixed blade 32 and the movable blade 34 can be imaged, but the camera 74 protrudes downward from the housing 24 and is likely to get in the way of work. According to the above configuration, since the camera 74 is located on the upper side of the housing 24, it is possible to image the areas on both the left and right sides of the fixed blade 32 and the movable blade 34. Furthermore, it is possible to prevent the camera 74 from protruding downward from the housing 24 and getting in the way of work.

[0087] In one or more embodiments, when the movable blade 34 is at its widest opening relative to the fixed blade 32 and the longitudinal direction of the housing 24 is horizontal, the camera 74 is positioned below the upper end of the movable blade 34.

[0088] By arranging the camera 74 on the upper surface side of the housing 24, even if the camera 74 protrudes upward from the housing 24, the camera 74 is less likely to get in the way of work as long as the camera 74 is arranged below the upper end of the movable blade 34 when the movable blade 34 is in the fully opened state. With the above configuration, even if the camera 74 protrudes upward from the housing 24, the camera 74 can be prevented from getting in the way of work.

[0089] In one or more embodiments, the blade further includes right and left lights 76 and 78 (examples of lighting) supported by the housing 24 to illuminate the area adjacent the fixed and movable blades 32 and 34 .

[0090] According to the above configuration, even in a dark environment, image data can be captured with the right light 76 and the left light 78 illuminating the areas near the fixed blade 32 and the movable blade 34, so that image data can be acquired under the same conditions as when image data is captured in a bright environment. This makes it possible to suppress variations in detection accuracy due to differences in environmental brightness.

[0091] In one or more embodiments, a right light 76 (an example of a right illuminator) is located on the right side of the housing 24 and a left light 78 (an example of a left illuminator) is located on the left side of the housing 24.

[0092] In a configuration in which the work machine 2 is equipped with the fixed blade 32 and the movable blade 34, if the work machine 2 is equipped only with the right side light 76 (or the left side light 78), the area to the right (or left) of the fixed blade 32 and the movable blade 34 will be illuminated, but the area to the left (or right) of the fixed blade 32 and the movable blade 34 will be blocked by the fixed blade 32 and the movable blade 34 and will not be illuminated, making it difficult to illuminate the areas on both the left and right sides of the fixed blade 32 and the movable blade 34. According to the above configuration, the work machine 2 is equipped with both the right side light 76 and the left side light 78, so that the areas on both the left and right sides of the fixed blade 32 and the movable blade 34 can be properly illuminated.

[0093] In one or more embodiments, the control unit 14 identifies, among the pixels contained in the image data, pixel P1 (an example of a first pixel) located at a position corresponding to the fixed blade 32 and pixel P2 (an example of a second pixel) located at a position not corresponding to the fixed blade 32 or the movable blade 34, and determines whether the camera 74 is obstructed by an obstacle 84 based on the hue, saturation and / or brightness of pixel P1 and pixel P2 when expressed in HSV format.

[0094] When the camera 74 is not blocked by the obstacle 84, the pixel P1 arranged at a position corresponding to the fixed blade 32 always reflects the same color (i.e., the color of the fixed blade 32), and the pixel P2 arranged at a position not corresponding to the fixed blade 32 or the movable blade 34 reflects the color of the background. In this case, the hue, saturation, and brightness of the pixel P1 and the pixel P2 are different from each other. In contrast, when the camera 74 is blocked by the obstacle 84, the same color of the obstacle 84 is reflected in the pixel P1 arranged at a position corresponding to the fixed blade 32 and in the pixel P2 arranged at a position not corresponding to the fixed blade 32 or the movable blade 34. In this case, the hue, saturation, and brightness of the pixel P1 and the pixel P2 are approximately the same. According to the above configuration, it is possible to appropriately determine whether the camera 74 is blocked by the obstacle 84 or not based on the hue, saturation, and / or brightness of the pixel P1 arranged at a position corresponding to the fixed blade 32 and the pixel P2 arranged at a position not corresponding to the fixed blade 32 or the movable blade 34.

[0095] In one or more embodiments, the left / right viewing angle of the camera 74 is in the range of 60° to 120°.

[0096] If the angle of view in the horizontal direction is too wide, the glove 80 will appear in the image data even if the glove 80 is not very close to the fixed blade 32 and the movable blade 34 in the horizontal direction. Conversely, if the angle of view in the horizontal direction is too narrow, the glove 80 will not appear in the image data until the glove 80 comes very close to the fixed blade 32 and the movable blade 34 in the horizontal direction. With the above configuration, it is possible to appropriately detect whether the glove 80 is close to the fixed blade 32 and the movable blade 34 in the horizontal direction.

[0097] In one or more embodiments, the vertical viewing angle of the camera 74 is in the range of 45° to 90°.

[0098] If the angle of view in the vertical direction is too wide, the glove 80 will appear in the image data even if the glove 80 is not very close to the fixed blade 32 and the movable blade 34 in the vertical direction. Conversely, if the angle of view in the vertical direction is too narrow, the glove 80 will not appear in the image data until the glove 80 gets quite close to the fixed blade 32 and the movable blade 34 in the vertical direction. With the above configuration, it is possible to appropriately detect whether the glove 80 is close to the fixed blade 32 and the movable blade 34 in the vertical direction.

[0099] In one or more embodiments, the shutter speed of the camera 74 is in the range of 0.1 ms to 2 ms.

[0100] According to the above configuration, when the work machine 2 is used outdoors, image data can be captured at an appropriate brightness.

[0101] In one or more embodiments, the safety mode includes a first safety mode that operates safer than the normal mode, and a second safety mode that operates safer than the first safety mode. The control unit 14 is configured to operate the work machine 2 in the first safety mode when it is determined that the glove 80 approaches the fixed blade 32 and the movable blade 34 at a level 1 approach level (an example of a first approach level) based on the number of pixels whose hues are within a predetermined range among pixels included in the image data captured by the camera 74. The control unit 14 is configured to operate the work machine 2 in the second safety mode when it is determined that the glove 80 approaches the fixed blade 32 and the movable blade 34 at a level 2 approach level (an example of a second approach level) that is closer than level 1 based on the number of pixels whose hues are within a predetermined range among pixels included in the image data captured by the camera 74.

[0102] According to the above configuration, the work machine 2 can be operated in a stepwise safer mode depending on the approach level of the glove 80 to the fixed blade 32 and the movable blade 34. [Explanation of symbols]

[0103] 2: Work equipment 4: Battery unit 6: Switch unit 8: Unit of Work 10: Cable 12: Connection cord 14: Control section 16: Battery pack 18: Main power switch 20: Indicator lamp 22: Buzzer 24: Housing 26: Grip 27: Connector 28: Trigger 30: Guard 32: Fixed blade 34: Movable blade 36: Electric motor 38: Power transmission section 40: Trigger position detector 42: Output shaft 44: Reduction mechanism 46: Screw shaft 48: Nut 50: Nut casing 52: Link arm 54: Lower blade part 56: Support part 58: Upper blade part 60: Lever section 62: Bolt 64: Pin 66: Pin 68: Magnet 70: Spring 72: Trigger position sensor 74: Camera 76: Right side light 78: Left light 80: Gloves 82: branch 84: Obstacle

Claims

1. A working section; A prime mover that drives the working unit; an imaging unit that images an area near the working unit; A working machine including a control unit, The work machine is operable in a normal mode in which it operates normally and in a safety mode in which it operates safer than the normal mode, The control unit is configured to operate the work machine in the safety mode when it is determined that an object is approaching the working unit based on the number of pixels contained in image data captured by the imaging unit, the number of pixels whose hue when expressed in HSV format is within a predetermined range.

2. 2. The work machine of claim 1, wherein the control unit is configured to determine whether or not the object is approaching the working unit based on the number of pixels contained in the image data captured by the imaging unit, the number of pixels whose hue is within the specified range and whose saturation when expressed in HSV format is equal to or greater than a threshold value.

3. The work machine according to claim 2 , wherein the control unit sets the threshold value to a lower value as the brightness of a pixel included in the image data captured by the imaging unit is higher when expressed in HSV format.

4. The work machine according to any one of claims 1 to 3, wherein the predetermined range is a range of 230° to 360°.

5. The apparatus further includes a housing that supports the working unit and the imaging unit and is held by a user.

5. The work machine according to claim 1, wherein the working unit comprises a fixed blade, and a movable blade that is rotatable about a rotation axis that extends in the left-right direction relative to the fixed blade and is driven by the prime mover.

6. The work machine according to claim 5 , wherein the imaging unit is disposed on an upper surface side of the housing.

7. 7. The work machine according to claim 6, wherein when the movable blade is in a maximum open state relative to the fixed blade and the longitudinal direction of the housing is horizontal, the imaging unit is disposed below an upper end of the movable blade.

8. The work machine according to claim 5 , further comprising an illumination unit supported by the housing and configured to illuminate an area adjacent to the working unit.

9. The work machine according to claim 8 , wherein the lighting section comprises a right side lighting section disposed on a right side of the housing, and a left side lighting section disposed on a left side of the housing.

10. A work machine according to any one of claims 5 to 9, wherein the control unit identifies, among the pixels included in the image data, a first pixel located at a position corresponding to the fixed blade and a second pixel located at a position not corresponding to the fixed blade or the movable blade, and determines whether or not the imaging unit is obstructed by an obstacle based on the hue, saturation and / or brightness of the first pixel and the second pixel when expressed in HSV format.

11. The work machine according to any one of claims 5 to 10, wherein the imaging unit has a left-right angle of view within a range of 60° to 120°.

12. The work machine according to any one of claims 5 to 11, wherein the imaging unit has a vertical angle of view within a range of 45° to 90°.

13. The work machine according to any one of claims 5 to 12, wherein the shutter speed of the imaging unit is within a range of 0.1 ms to 2 ms.

14. the safety modes include a first safety mode that operates more safely than the normal mode, and a second safety mode that operates more safely than the first safety mode; the control unit is configured to operate the work machine in the first safety mode when it is determined that the object is approaching the working unit at a first approach level based on the number of pixels, the hue of which is within the predetermined range, among pixels included in the image data captured by the imaging unit, and The control unit is configured to operate the work machine in the second safety mode when it is determined that the object is approaching the working unit at a second approach level closer than the first approach level based on the number of pixels, among the pixels included in the image data captured by the imaging unit, whose hue is within the specified range.

Images