Patent Publication Number: US-2021170589-A1

Title: Work support device, work support method, computer program product, and work support system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-222378, filed on Dec. 9, 2019; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a work support device, a work support method, a computer program product, and a work support system. 
     BACKGROUND 
     Devices that support work such as assembly work and installation work of a heavy object have been known. For example, in a disclosed configuration, a workpiece weight for balancing with the weight of a workpiece as a heavy object is provided at an end part of an arm that supports the workpiece. 
     However, by the conventional technology, there are cases where a workpiece weight disturbs the work, and it has been difficult to support work while avoiding various interferers in a given region such as the inside of a passage. In other words, by the conventional technology, there are difficult cases of achieving improved work support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a work support system according to an embodiment; 
         FIG. 2  is a schematic diagram of an arm unit according to the embodiment; 
         FIG. 3A  is an enlarged schematic diagram of a grasping part according to the embodiment; 
         FIG. 3B  is an enlarged schematic diagram of the grasping part according to the embodiment; 
         FIG. 3C  is an enlarged schematic diagram of the grasping part according to the embodiment; 
         FIG. 4  is a functional block diagram of the work support system according to the embodiment; 
         FIG. 5A  is an explanatory diagram of actuation restriction of the arm unit in accordance with joint angles of joint parts according to the embodiment; 
         FIG. 5B  is an explanatory diagram of actuation restriction of the arm unit in accordance with the joint angles of the joint parts according to the embodiment; 
         FIG. 5C  is an explanatory diagram of actuation restriction of the arm unit in accordance with the joint angles of the joint parts according to the embodiment; 
         FIG. 5D  is an explanatory diagram of actuation restriction of the arm unit in accordance with the joint angles of the joint parts according to the embodiment; 
         FIG. 6  is an explanatory diagram of a set spatial region according to the embodiment; 
         FIG. 7A  is an explanatory diagram of actuation restriction of the set spatial region according to the embodiment; 
         FIG. 7B  is an explanatory diagram of actuation restriction of the set spatial region according to the embodiment; 
         FIG. 8  is an explanatory diagram of actuation restriction of the arm unit in a close state according to the embodiment; 
         FIG. 9  is a flowchart illustrating the flow of work support processing according to the embodiment; 
         FIG. 10  is a flowchart illustrating the flow of interrupt processing according to the embodiment; and 
         FIG. 11  is a diagram illustrating a hardware configuration according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     According an embodiment, a work support device includes an arm unit, a brake unit, a state determination unit, and a brake control unit. The arm unit includes a grasping part configured to grasp an object, a plurality of joint parts, and a plurality of link parts actuatably coupled through each joint part. The brake unit is provided to at least one of the joint parts to restrict actuation of the arm unit. The state determination unit is configured to determine a state of the arm unit. The brake control unit is configured to control the brake unit to restrict the actuation of the arm unit in accordance with the state of the arm unit. The following describes a work support device, a work support method, a computer program product, and a work support system in detail with reference to the accompanying drawings. 
       FIG. 1  is a schematic diagram illustrating an exemplary work support system  1  of the present embodiment. 
     The work support system  1  is a system for supporting work by a worker M. The worker M is an exemplary user. For example, the work support system  1  supports work by the worker M in a passage. 
     The passage has such a size that the worker M can work inside. The passage is, for example, an elevator hoistway  2 , a tunnel in which an object such as a vehicle moves, or a sewer. The present embodiment describes an example in which the passage is the elevator hoistway  2 . The elevator hoistway  2  is also referred to as an elevator shaft. The work support system  1  may be any system that supports work by the worker M, and its support target work is not limited to work in the passage such as the elevator hoistway  2 . 
     The work support system  1  includes a work support device  10 . 
     In the exemplary form described in the present embodiment, the work support device  10  is disposed in the elevator hoistway  2 . In addition, in the exemplary form described in the present embodiment, the work support device  10  is disposed at a scaffold  3 . 
     The scaffold  3  is a cradle capable of accommodating the worker M. For example, the scaffold  3  is a scaffold unit used in assembly of an elevator or the like, an elevator car, or a workbench. The scaffold  3  is detachably installed in the elevator hoistway  2  at maintenance or the like. The scaffold  3  disposed in the elevator hoistway  2  is supported by a displacement member disposed at a top part of the elevator hoistway  2  through a guide rail  4  and a cable. The scaffold  3  can be moved in a height direction Z along the guide rail  4  in the elevator hoistway  2  by the displacement member. 
     The work support device  10  installed at the scaffold  3  is movable in the height direction Z in the elevator hoistway  2 . Alternatively, the work support device  10  may be fixed in the elevator hoistway  2  or may be detachably installed at the scaffold  3  disposed in the elevator hoistway  2 . The following description of the present embodiment assumes a case in which the worker M on the scaffold  3  disposed in the elevator hoistway  2  works in the elevator hoistway  2 . 
     The work support device  10  includes a control unit  20  and an arm unit  30 . 
     The control unit  20  controls actuation of the arm unit  30 . The arm unit  30  is an assist mechanism for holding an object T. In other words, the arm unit  30  is a mechanism for supporting handling of the object T by the worker M. 
     The object T is a target that the worker M contacts or holds at work. Examples of the object T include various equipment and tools such as an electric drill and an impact driver, and various attachment members and fixation members such as a bracket, a guide rail, a counter weight, and a component. 
     In the present embodiment, the arm unit  30  is supported at the scaffold  3  by a support unit  5 . The support unit  5  is provided to an outer frame member  3 A of the scaffold  3  and movably supports the arm unit  30  along the outer frame member  3 A. For example, the support unit  5  movably supports the arm unit  30  in an extension direction (the direction of arrow Y) of the outer frame member  3 A. The support unit  5  is, for example, a linear movement slider. Accordingly, the arm unit  30  has a compact configuration and has a movable range in which work by the worker M can be assisted without interference with a work area of the worker M. 
       FIG. 2  is a schematic diagram of an example of the arm unit  30 . 
     The arm unit  30  includes a grasping part  32 , a plurality of joint parts  34 , and a plurality of link parts  36 . 
     The grasping part  32  is a mechanism that grasps the object T. The grasping part  32  includes a mechanism such as a pinching mechanism or an electromagnetic chuck to grasp the object T. 
     Each link part  36  is a bar member. In the present embodiment, the arm unit  30  includes, as the link parts  36 , a link part  36 A and a link part  36 B. The link parts  36  are actuatably coupled through the joint parts  34 . 
     “Actuation” means at least one of linear movement, rotation, and pivot movement. “Actuatable” means that at least one of linear movement, rotation, and pivot movement is possible. In an exemplary form described in the present embodiment, “actuation” means rotation, and “actuatable” means rotatable. 
     The joint parts  34  are a coupling mechanism for coupling a pair of the link part  36 A and the link part  36 B and a pair of the link part  36 B and the grasping part  32  in an actuatable manner. In the present embodiment, the arm unit  30  includes joint parts  34 A to  34 F as the joint parts  34 . 
     The joint part  34 A and the joint part  34 B couple the link part  36 A on the support unit  5  in an actuatable manner. In the present embodiment, the joint part  34 A is a horizontal rotation joint that is horizontally rotatable. The rotational axis of the joint part  34 B orthogonally crosses the rotational axis of the joint part  34 A. The joint part  34 B is a vertical rotation joint that is vertically rotatable. 
     The joint part  34 C and the joint part  34 D couple the link part  36 A and the link part  36 B with each other in an actuatable manner. In the present embodiment, the joint part  34 C is a horizontal rotation joint. The rotational axis of the joint part  34 D orthogonally crosses the rotational axis of the joint part  34 C. The joint part  34 D is a vertical rotation joint. The link part  36 A has a parallel-link structure. With this configuration, the joint part  34 C is horizontally rotatable irrespective of the rotation angles of the joint part  34 A and the joint part  34 B. 
     The joint part  34 E and the joint part  34 F couple the link part  36 B and the grasping part  32  with each other in an actuatable manner. In other words, the link part  36 B and the grasping part  32  are coupled with each other through the joint part  34 E and the joint part  34 F. In the present embodiment, the joint part  34 E is a horizontal rotation joint. The rotational axis of the joint part  34 F orthogonally crosses the rotational axis of the joint part  34 E. The joint part  34 F is a vertical rotation joint. The link part  36 B has a parallel-link structure. With this configuration, the joint part  34 E is horizontally rotatable irrespective of the rotation angles of the joint part  34 C and the joint part  34 D. 
     As described above, the arm unit  30  includes the joint parts  34 . Thus, it is advantageous that the worker M can easily intuitively understand motion of the arm unit  30  and safely perform work. 
     In addition, as described above, at least one of the joint parts  34  is a horizontal rotation joint, and at least another one of the joint parts  34  is a vertical rotation joint. Specifically, in the present embodiment, the joint part  34 A, the joint part  34 C, and the joint part  34 E are horizontal rotation joints. The link part  36 A and the link part  36 B each have a parallel-link structure. 
     With this configuration, the posture of each of the joint part  34 A, the joint part  34 C, and the joint part  34 C is constantly horizontally maintained. Thus, the arm unit  30  of the present embodiment does not need to support gravitational force through actuation of these horizontal rotation joints. In addition, the arm unit  30  can achieve necessary torque reduction through these horizontal rotation joints when the object T held by the grasping part  32  is a heavy object having a weight equal to or heavier than a threshold value. Moreover, it is possible to reduce the size of the mechanism of the arm unit  30  and the electrical driving power of the arm unit  30 . 
     In the arm unit  30 , the rotational axis of at least one of the joint parts  34  only needs to be orthogonal to the rotational axis of at least another one of the joint parts  34 , and the rotational axes are not limited to the horizontal and vertical directions. 
     The grasping part  32  and the link part  36 B are coupled with each other through the joint part  34 E and the joint part  34 F. The joint part  34 E is a horizontal rotation joint. The joint part  34 F is a vertical rotation joint. The rotational axis of the joint part  34 F orthogonally crosses the rotational axis of the joint part  34 E. 
       FIGS. 3A to 3C  are enlarged schematic diagrams of the grasping part  32 . As described above, the grasping part  32  and the link part  36 B are coupled with each other through the joint part  34 E and the joint part  34 F. Thus, the posture of the object T held by the grasping part  32  is easily changed upward, downward, rightward, and leftward about the axes (refer to  FIGS. 3A to 3C ). The joint part  34 F may be a rotational body that has a spherical shape and is rotatable by 360°. 
     A handle part  48  to be grasped by the worker M during work is provided to the joint part  34 E. The handle part  48  is a handle for the worker M to change the posture of the arm unit  30  or operate the position and posture of the object T grasped by the grasping part  32 . The worker M can move the grasping part  32  in a desired direction by operating the handle part  48 . 
     An input unit  46  is provided to the handle part  48 . The input unit  46  is an input mechanism for receiving various operation instructions from the worker M. In the present embodiment, the input unit  46  receives, for example, input of a switching instruction to perform switching between an automatic mode and a manual mode. Details of the automatic mode and the manual mode will be described later. 
     The description continues with reference back to  FIG. 2 . 
     Each joint part  34  of the arm unit  30  is provided with a drive unit  40 , a brake unit  41 , and an angle sensor  42 . 
     Specifically, the joint part  34 A to the joint part  34 F are provided with drive unit  40 A to drive unit  40 F, brake unit  41 A to brake unit  41 F, and angle sensor  42 A to angle sensor  42 F, respectively. When collectively described, the joint part  34 A to the joint part  34 F are referred to as the joint parts  34 . When collectively described, the drive unit  40 A to the drive unit  40 F are referred to as the drive units  40 . When collectively described, the brake unit  41 A to the brake unit  41 F are referred to as the brake units  41 . When collectively described, the angle sensor  42 A to the angle sensor  42 F are referred to as the angle sensors  42 . 
     The drive unit  40  actuates the corresponding joint part  34 . The drive unit  40  is provided in at least one of the joint parts  34 . The drive unit  40  is, for example, an actuator. In the exemplary form described in the present embodiment, the drive unit  40  is provided in each joint part  34  included in the arm unit  30 . In the present embodiment, the drive unit  40  rotatably drives the joint part  34  provided with the drive unit  40 . The drive unit  40  is driven under control of the control unit  20  to be described later (to be described later in detail). The drive unit  40  may be a well-known mechanism. 
     The brake unit  41  restricts the actuation of the arm unit  30 . The brake unit  41  is provided in at least one of the joint parts  34 . In the exemplary form described in the present embodiment, the brake unit  41  is provided in each joint part  34  included in the arm unit  30 . The brake unit  41  restricts actuation of the joint part  34  provided with the brake unit  41 , thereby restricting actuation of the arm unit  30 . “Restriction of actuation” means at least one of deceleration of the speed of actuation of the arm unit  30  and the joint part  34  and stopping of actuation of the arm unit  30  and the joint part  34 . In other words, in the present embodiment, the brake unit  41  controls deceleration of the rotational speed of the joint part  34  or stopping of rotation of the joint part  34 . The brake unit  41  may be a well-known braking mechanism. 
     The angle sensor  42  is a sensor that measures a joint angle that is a variable amount (VA) as the rotation angle of the joint part  34 . In the present embodiment, the angle sensor  42  is provided in each joint part  34 . The angle sensor  42  measures, as the joint angle, the rotation angle of the joint part  34  provided with the angle sensor  42  based on a reference position. The reference position may be set in advance. 
     The arm unit  30  also includes an obstacle sensing unit  43 , a force sensor  44 , and a target position detection unit  45 . 
     The obstacle sensing unit  43  senses any obstacle around the arm unit  30 . An obstacle is an object that encumbers movement of the arm unit  30 . An obstacle is, for example, a user such as the worker M, a wall in the elevator hoistway  2 , or a member protruding from a wall. 
     In the exemplary form described in the present embodiment, the obstacle sensing unit  43  is disposed on the surface of each of the link part  36 A and the link part  36 B. The obstacle sensing unit  43  may be provided to each joint part  34  and the grasping part  32 . The obstacle sensing unit  43  is, for example, a well-known optical sensor but is not limited thereto. 
     The force sensor  44  is a force sensor that detects pressure applied to the arm unit  30  and the direction of the pressure. In the present embodiment, the force sensor  44  is provided to the grasping part  32 . Accordingly, the force sensor  44  detects pressure applied to the grasping part  32  and the direction of the pressure applied to the grasping part  32 . In other words, the force sensor  44  detects the strength of force applied for moving the grasping part  32  and the direction of pressurization. 
     The target position detection unit  45  is an exemplary detector. The target position detection unit  45  detects a target position. 
     The target position is a target position at which the grasping part  32  or the object T grasped by the grasping part  32  is to be positioned. In the present embodiment, the target position detection unit  45  specifies the relative position of the grasping part  32  with respect to the target position. The target position detection unit  45  is, for example, an image capturing device that obtains captured image data through image capturing. Hereinafter, the captured image data is also simply referred to as a captured image. 
     The following describes a functional configuration of the work support system  1  of the present embodiment. 
       FIG. 4  is a functional block diagram illustrating an exemplary functional configuration of the work support system  1  of the present embodiment. 
     The work support system  1  includes the work support device  10  and an external device  11 . The work support device  10  and the external device  11  are communicably connected with each other through a network N or the like. 
     The external device  11  is a well-known computer such as a server device. For example, the external device  11  is a server device such as a building information modeling (BIM) system that designs a work process or the like in advance. 
     The work support device  10  includes the control unit  20  and the arm unit  30 . The arm unit  30  includes the drive unit  40 , the brake unit  41 , the angle sensor  42 , the obstacle sensing unit  43 , the force sensor  44 , the target position detection unit  45 , and the input unit  46 . The control unit  20  is communicably connected with each of the drive unit  40 , the brake unit  41 , the angle sensor  42 , the obstacle sensing unit  43 , the force sensor  44 , the target position detection unit  45 , and the input unit  46 . 
     The control unit  20  is, for example, a dedicated or general-purpose computer. The control unit  20  includes a processing unit  50 , a storage unit  52 , and a communication unit  54 . The processing unit  50  is communicably connected with each of the communication unit  54  and the storage unit  52 . 
     Specifically, the processing unit  50 , the storage unit  52 , the communication unit  54 , the drive unit  40 , the brake unit  41 , the angle sensor  42 , the obstacle sensing unit  43 , the force sensor  44 , the target position detection unit  45 , and the input unit  46  are communicably connected with one another through a bus  56 . 
     The storage unit  52  stores therein various kinds of data. The storage unit  52  is, for example, a semiconductor memory device such as a random-access memory (RAM) or a flash memory, a hard disk, or an optical disc. The storage unit  52  may be a storage device provided outside the work support device  10 . Alternatively, the storage unit  52  may be a storage medium. Specifically, the storage medium may store or temporarily store therein computer programs and various kinds of information downloaded through a local area network (LAN), the Internet, or the like. The storage unit  52  may be formed of a plurality of storage media. 
     At least one of the storage unit  52  and the processing unit  50  may be mounted on the external device  11  such as a server device connected with the network N. In addition, at least one of functional components (to be described later) included in the processing unit  50  may be mounted on the external device  11  such as a server device connected with the processing unit  50  through the network N. 
     The processing unit  50  includes an acquisition unit  50 A, a target angle derivation unit  50 B, a movement direction derivation unit  50 C, a spatial position derivation unit  50 D, a reception unit  50 E, a movement control unit  50 F, a state determination unit  50 G, and a brake control unit  50 H. The state determination unit  50 G includes a joint angle determination unit  50 I, a positioning determination unit  50 J, an in-region operation determination unit  50 K, and a collision determination unit  50 L. 
     At least one of the acquisition unit  50 A, the target angle derivation unit  50 B, the movement direction derivation unit  50 C, the spatial position derivation unit  50 D, the reception unit  50 E, the movement control unit  50 F, the state determination unit  50 G, the brake control unit  50 H, the joint angle determination unit  50 I, the positioning determination unit  50 J, the in-region operation determination unit  50 K, and the collision determination unit  50 L is implemented by, for example, one or a plurality of processors. For example, each of the above-described components may be implemented through execution of a computer program by a processor such as a central processing unit (CPU), in other words, by software. Each of the above-described components may be implemented by a processor such as a dedicated integrated circuit (IC), in other words, by hardware. Each of the above-described components may be implemented by software and hardware in combination. When a plurality of processors are used, each processor may implement one of the components or may implement two or more of the components. 
     The acquisition unit  50 A acquires the joint angle of each joint part  34  from the corresponding angle sensor  42 . The acquisition unit  50 A also acquires an obstacle sensing result from the obstacle sensing unit  43 . The acquisition unit  50 A also acquires a result of detection of pressure applied to the grasping part  32  and the direction of the pressure from the force sensor  44 . The acquisition unit  50 A also acquires a result of detection of the target position from the target position detection unit  45 . 
     The acquisition unit  50 A also acquires the target position. The acquisition unit  50 A acquires the target position from the external device  11 . The target position is set in advance based on, for example, an operation instruction through the input unit  46  by the user and stored in the storage unit  52 . The acquisition unit  50 A acquires the target position by reading the target position from the communication unit  54 . The external device  11  may specify the target position for each work content or each work process. In this case, the acquisition unit  50 A can acquire the target position from the external device  11  through the communication unit  54 . 
     The target angle derivation unit  50 B derives a target angle that is the joint angle of each joint part  34  when the grasping part  32  is positioned at the target position. 
     The target angle derivation unit  50 B acquires the target position acquired by the acquisition unit  50 A and information of the current position of the support unit  5  supporting the joint part  34 A of the arm unit  30 . The information of the current position of the support unit  5  is information indicating the spatial position of the support unit  5 . The information of the current position of the support unit  5  is stored in, for example, the storage unit  52 . Then, the target angle derivation unit  50 B derives the posture of the arm unit  30  when the grasping part  32  of the arm unit  30  is positioned at the target position by using a well-known method or the like. Then, the target angle derivation unit  50 B derives, as the target angle, the joint angle of each joint part  34  of the arm unit  30  in the derived posture. In other words, the target angle derivation unit  50 B derives the target angle for each joint part  34  provided to the arm unit  30 . Then, the target angle derivation unit  50 B stores the derived target angle in the storage unit  52  in association with identification information of the corresponding joint part  34 . 
     The movement direction derivation unit  50 C derives the movement direction of the arm unit  30 . Specifically, the movement direction derivation unit  50 C derives the movement direction of each of the grasping part  32 , the link part  36 B, and the joint parts  34  as components included in the arm unit  30  by using the result of detection of pressure applied to the grasping part  32  and the direction of the pressure, which are acquired from the force sensor  44 , and the result of detection of the joint angle of each joint part  34 , which is acquired from the corresponding angle sensor  42 . 
     The spatial position derivation unit  50 D derives the spatial position of the arm unit  30 . The spatial position of the arm unit  30  is information indicating the position and posture of each part included in the arm unit  30 . For example, the spatial position of the arm unit  30  is information indicating the position coordinates of each of the grasping part  32 , the joint parts  34 , and the link parts  36  as parts included in the arm unit  30 , in the real space. The spatial position of the arm unit  30  may be information further including the position coordinates of the object T grasped by the grasping part  32 . 
     For example, the spatial position derivation unit  50 D derives the spatial position of the arm unit  30  by applying the angle of each joint part  34 , which is acquired by the acquisition unit  50 A, to a stereoscopic model of the arm unit  30  that is produced in advance. The spatial position derivation unit  50 D may use another method to derive the spatial position of the arm unit  30 . For example, the arm unit  30  may be provided with a position sensor, and the spatial position derivation unit  50 D may derive the spatial position of the arm unit  30  by using a result of detection by the position sensor. 
     The reception unit  50 E acquires, from the input unit  46 , mode information indicating the automatic mode or the manual mode. 
     An acquisition mode is a mode in which the arm unit  30  is manually moved by the worker M. The automatic mode is a mode in which the arm unit  30  is moved to the target position under control of the movement control unit  50 F. The user operates the input unit  46  to input a switching instruction to perform switching from the manual mode to the automatic mode or from the automatic mode to the manual mode. 
     Thus, the input unit  46  may be a switch for inputting switching between these modes. The reception unit  50 E acquires the mode information indicating the manual mode by receiving a switching instruction to perform switching to the manual mode through the input unit  46 . The reception unit  50 E acquires the mode information indicating the automatic mode by receiving a switching instruction to perform switching to the automatic mode through the input unit  46 . 
     The movement control unit  50 F moves the grasping part  32  of the arm unit  30  to the target position. Specifically, when having received a switching instruction to perform switching to the automatic mode, the movement control unit  50 F starts controlling the drive unit  40  to move the grasping part  32  to the target position. The movement control unit  50 F controls the drive unit  40  of each joint part  34  provided to the arm unit  30  so that the joint part  34  has the corresponding target angle derived by the target angle derivation unit  50 B. Under the control of the movement control unit  50 F, the grasping part  32  of the arm unit  30  starts moving toward the target position. 
     When having received a switching instruction to perform switching to the manual mode, the movement control unit  50 F does not control the drive units  40 . In this case, upon operation of the handle part  48  by the worker M, the grasping part  32  starts moving in a direction desired by the worker M, and the arm unit  30  starts moving. 
     The state determination unit  50 G determines the state of the arm unit  30 . Hereinafter, the state of the arm unit  30  is referred to as an arm state. In the present embodiment, the state determination unit  50 G determines the arm state of the arm unit  30  during manual or automatic movement of the arm unit  30 . The brake control unit  50 H controls each brake unit  41  in accordance with the arm state to restrict actuation of the arm unit  30 . 
     The following describes the state determination unit  50 G and the brake control unit  50 H in detail. 
     The state determination unit  50 G includes the joint angle determination unit  50 I, the positioning determination unit  50 J, the in-region operation determination unit  50 K, and the collision determination unit  50 L. 
     The joint angle determination unit  50 I determines, as the arm state, whether at least one of the joint parts  34  has reached the target angle derived by the target angle derivation unit  50 B. Specifically, the joint angle determination unit  50 I determines whether the joint angle acquired from at least one of the angle sensors  42  has reached the target angle of the joint part  34  provided with that angle sensor  42 . 
     The brake control unit  50 H restricts actuation of the arm unit  30  by restricting actuation of each joint part  34  determined to have reached the target angle. 
       FIGS. 5A to 5D  are explanatory diagrams of exemplary restriction of actuation of the arm unit  30  in accordance with the joint angles of some joint parts  34 . Examples of the state of the arm unit  30  are illustrated in a temporally sequential manner from  FIGS. 5A to 5D . For example, assume that the target angle derivation unit  50 B has derived a joint angle α as the target angle of the joint part  34 A, a joint angle β as the target angle of the joint part  34 C, and a joint angle γ as the target angle of the joint part  34 E. 
     For example, assume that, as illustrated in  FIG. 5A , the worker M operates the handle part  48  and applies force in the direction of arrow Dl to the grasping part  32  to move the grasping part  32  toward a target position P. Then, assume that, as illustrated in  FIG. 5B , the joint angle of the joint part  34 A has become the target joint angle α. In this case, the joint angle determination unit  50 I determines that the joint angle of the joint part  34 A has reached the target angle. Accordingly, the brake control unit  50 H restricts rotation of the joint part  34 A by controlling the brake unit  41 A of the joint part  34 A. 
     Then, assume that the worker M further operates the handle part  48  and applies force in the direction of arrow D 2  to the grasping part  32  to move the grasping part  32  toward the target position P (refer to  FIG. 5B ). Assume that, through this operation, the joint angle of the joint part  34 C has become the target joint angle β as illustrated in  FIG. 5C . In this case, the joint angle determination unit  50 I determines that the joint angle of the joint part  34 C has reached the target angle. Accordingly, the brake control unit  50 H restricts rotation of the joint part  34 C by controlling the brake unit  41 C of the joint part  34 C. 
     Then, assume that the worker M further operates the handle part  48  and applies force in the direction of arrow D 3  to the grasping part  32  to move the grasping part  32  toward the target position P (refer to  FIG. 5C ). Assume that, through this operation, the joint angle of the joint part  34 E has become the target joint angle γ as illustrated in  FIG. 5D . In this case, the joint angle determination unit  50 I determines that the joint angle of the joint part  34 E has reached the target angle. Accordingly, the brake control unit  50 H restricts rotation of the joint part  34 E by controlling the brake unit  41 E of the joint part  34 E. 
     In this manner, in the arm unit  30 , rotation of each joint part  34  having reached the corresponding target angle is sequentially restricted. Thus, the object T grasped by the grasping part  32  safely and easily arrives at the target position P. 
     The joint angle determination unit  50 I and the brake control unit  50 H execute the same processing in the automatic mode as well in which the arm unit  30  automatically operates as the movement control unit  50 F controls the drive unit  40  provided to each joint part  34  of the arm unit  30 . Accordingly, the object T safely and easily arrives at the target position P in a case in which the arm unit  30  is driven under control of the movement control unit  50 F to move the object T to the target position P, as well. 
     The description continues with reference back to  FIG. 4 . Subsequently, the positioning determination unit  50 J will be described below. 
     The positioning determination unit  50 J determines, as the arm state, whether the grasping part  32  is positioned at the target position P. In the present embodiment, the positioning determination unit  50 J determines whether the grasping part  32  is positioned at the target position P based on a result of detection by the target position detection unit  45 . 
     For example, the positioning determination unit  50 J acquires a result of detection of the target position P by the target position detection unit  45  from the acquisition unit  50 A. As described above, the target position detection unit  45  is, for example, an image capturing device. In this case, the positioning determination unit  50 J specifies the target position P and the relative position of the grasping part  32  with respect to the target position P by performing image analysis of a captured image obtained through image capturing by the target position detection unit  45 . The relative position detection may be performed on the target position detection unit  45  side. Then, the positioning determination unit  50 J may determine, as the arm state, whether the relative position of the grasping part  32  with respect to the target position P coincides with the target position P. 
     When it is determined by the positioning determination unit  50 J that the grasping part  32  is positioned at the target position P, the brake control unit  50 H may control each brake unit  41  to restrict actuation of the arm unit  30 . Specifically, in the present embodiment, the brake control unit  50 H may restrict rotation of the brake unit  41  of each joint part  34  provided to the arm unit  30 . 
     The accuracy of positioning the grasping part  32  and the object T grasped by the grasping part  32  to the target position P can be improved by controlling the brake control unit  50 H in accordance with a result of the determination by the positioning determination unit  50 J. 
     The positioning determination unit  50 J and the brake control unit  50 H execute the same processing in the automatic mode as well in which the arm unit  30  automatically operates as the movement control unit  50 F controls the drive unit  40  provided to each joint part  34  of the arm unit  30 . Accordingly, the object T is accurately positioned to the target position P in a case in which the arm unit  30  is driven under control of the movement control unit  50 F to move the object T to the target position P, as well. 
     Subsequently, the in-region operation determination unit  50 K and the collision determination unit  50 L will be described below. 
     The in-region operation determination unit  50 K determines, as the arm state, whether at least a partial region of the arm unit  30  is likely to protrude from the inside of a set spatial region to the outside of the set spatial region. 
     The set spatial region is set in advance as a region in which the arm unit  30  can be safely actuated. 
       FIG. 6  is an explanatory diagram of an exemplary set spatial region E. For example, the set spatial region E is a region in which the arm unit  30  can be safely actuated when the arm unit  30  is actuated by the worker M working with the arm unit  30 . Specifically, the set spatial region E includes at least a part of the above-described movable range of the arm unit  30 . Set-spatial-region information of the set spatial region E may be stored in the storage unit  52  in advance. The set-spatial-region information may be changeable as appropriate based on an operation instruction through the input unit  46  by the worker M, information received from the external device  11 , or the like. 
     In the present embodiment, the in-region operation determination unit  50 K determines whether the arm unit  30  is likely to protrude to the outside of the set spatial region E based on the spatial position of the arm unit  30 , the movement direction of the arm unit  30 , and the set spatial region E of the set-spatial-region information. 
     For example, the in-region operation determination unit  50 K acquires the spatial position of the arm unit  30 , which is derived by the spatial position derivation unit  50 D. For example, the in-region operation determination unit  50 K acquires the movement direction of the arm unit  30 , which is derived by the movement direction derivation unit  50 C. For example, the in-region operation determination unit  50 K acquires the set-spatial-region information of the set spatial region E from the storage unit  52 . 
     Then, the in-region operation determination unit  50 K predicts, by simulation, whether at least a partial region of the parts (the grasping part  32 , the joint parts  34 , and the link parts  36 ) included in the arm unit  30 , which are indicated by the acquired spatial position of the arm unit  30 , is positioned outside the set spatial region E when movement of the arm unit  30  in the movement direction is continued. Then, when a result of the prediction indicates that the region is positioned outside the set spatial region E, the in-region operation determination unit  50 K determines that the arm unit  30  is likely to protrude to the outside of the set spatial region E. 
     When a result of the prediction indicates that the region is positioned inside the set spatial region E, the in-region operation determination unit  50 K determines that the arm unit  30  is not likely to protrude to the outside of the set spatial region E. 
     The current position of at least a partial region of the parts (the grasping part  32 , the joint parts  34 , and the link parts  36 ) included in the arm unit  30  in the real space, which are indicated by the acquired spatial position of the arm unit  30 , is positioned outside the set spatial region E in some cases. In such a case, the in-region operation determination unit  50 K may further determine that the arm unit  30  is likely to protrude to the outside of the set spatial region E. 
     When it is determined that the arm unit  30  is likely to protrude to the outside of the set spatial region E, the brake control unit  50 H controls the brake unit  41  to restrict actuation of the arm unit  30 . 
     Specifically, the brake control unit  50 H specifies a joint part  34  that contributes to positional movement of a region of each part included in the arm unit  30 , which is determined to be likely to protrude to the outside of the set spatial region E by the in-region operation determination unit  50 K. Then, the brake control unit  50 H controls the corresponding brake unit  41  to restrict rotation of the specified joint part  34 . 
       FIGS. 7A and 7B  are explanatory diagrams of exemplary actuation restriction in the set spatial region E. Examples of the state of the arm unit  30  are illustrated in a temporally sequential manner from  FIGS. 7A to 7B . 
     For example, assume that, as illustrated in  FIG. 7A , the worker M operates the handle part  48  and applies force in the direction of arrow D 10  to the grasping part  32  to move the grasping part  32  toward the target position P. 
     In this case, the joint part  34 C and the joint part  34 D are likely to be positioned outside the set spatial region E when movement of the arm unit  30  in the direction of the arrow D 10  is continued as force in the direction of the arrow D 10  is continuously applied. In this case, the in-region operation determination unit  50 K determines that the joint part  34 C and the joint part  34 D of the arm unit  30  are likely to protrude to the outside of the set spatial region E based on the spatial position of the arm unit  30 , which is derived by the spatial position derivation unit  50 D, the movement direction of the arm unit  30 , which is derived by the movement direction derivation unit  50 C, and the set spatial region E of the set-spatial-region information. 
     Thus, in this case, the brake control unit  50 H specifies a joint part  34  that contributes to positional movement of the joint part  34 C and the joint part  34 D determined to be likely to protrude to the outside of the set spatial region E by the in-region operation determination unit  50 K. For example, assume that the brake control unit  50 H specifies the joint part  34 A, the joint part  34 C, and the joint part  34 E. In this case, the brake control unit  50 H controls the brake unit  41 A, the brake unit  41 C, and the brake unit  41 E to restrict rotation of the specified joint parts  34 A,  34 C, and  34 E. 
     Accordingly, movement of the arm unit  30  due to application of force in the direction of the arrow D 10  is restricted. Specifically, the brake control unit  50 H controls the brake unit  41  based on a result of determination by the in-region operation determination unit  50 K, thereby preventing at least a partial region of the arm unit  30  from protruding to the outside of the set spatial region E. 
     Then, assume that the worker M further operates the handle part  48  and applies force in the direction of arrow D 12 , which is different from the direction of the arrow D 10 , to the grasping part  32  to move the grasping part  32  toward the target position P. 
     In this case, similarly to the above description, the in-region operation determination unit  50 K determines whether at least a partial region of the arm unit  30  is likely to protrude to the outside of the set spatial region E as movement in the direction of the arrow D 12  is continued. In this example, assume a case in which it is determined that the set spatial region E is not likely to protrude to the outside of the set spatial region E. In this case, the brake control unit  50 H cancels rotation restriction on the joint part  34  rotation of which is restricted. Accordingly, as illustrated in  FIG. 7B , the worker M can move the grasping part  32  in a direction toward the object T by continuously applying force in the direction of the arrow D 12  to the grasping part  32 . 
     The in-region operation determination unit  50 K and the brake control unit  50 H execute the same processing in the automatic mode as well in which the arm unit  30  automatically operates as the movement control unit  50 F controls the drive unit  40  provided to each joint part  34  of the arm unit  30 . Accordingly, the object T safely and easily arrives at the target position P in a case in which the arm unit  30  is driven under control of the movement control unit  50 F to move the object T to the target position P, as well. 
     The description continues with reference back to  FIG. 4 . Subsequently, the collision determination unit  50 L will be described below. 
     The collision determination unit  50 L determines, as the arm state, whether at least a partial region of the arm unit  30  is in a close state in which the partial region of the arm unit  30  is close to an obstacle, based on a result of sensing by the obstacle sensing unit  43 . The close state means a state in which the distance between at least a partial region of the arm unit  30  and the obstacle is equal to or shorter than a predetermined threshold value. The close state may also mean that a state in which the distance between the arm unit  30  and the obstacle is likely to become equal to or shorter than the threshold value as the arm unit  30  continuously moves. In the example described in the present embodiment, the close state means that the distance between the arm unit  30  and the obstacle is likely to become equal to or shorter than the threshold value as the arm unit  30  continuously moves. The threshold value may be set in advance to be a value that can avoid a state in which the arm unit  30  and the arm unit  30  become close to each other enough to compromise safety and the close state is caused by changing the movement direction of the arm unit  30 . 
     In the present embodiment, the collision determination unit  50 L determines whether at least a partial region of the arm unit  30  is in the close state based on a result of sensing by the obstacle sensing unit  43 , and the movement direction of the arm unit  30 , which is derived from a result of sensing by the force sensor  44 . 
       FIG. 8  is an explanatory diagram of exemplary restriction of actuation of the arm unit  30  in the close state. 
     For example, assume that, as illustrated in  FIG. 8 , the worker M operates the handle part  48  and applies force in the direction of arrow D 13  to the grasping part  32  to move the grasping part  32  toward the target position P. 
     In this case, the distance between the link part  36 A and an obstacle B is likely to become equal to or shorter than the above-described threshold value as movement of the arm unit  30  in the direction of the arrow D 13  is continued through continuous application of force in the direction of the arrow D 13 . Thus, in this case, the in-region operation determination unit  50 K determines that at least a partial region of the arm unit  30  is in the close state based on the movement direction of the arm unit  30 , which is derived from a result of sensing by the force sensor  44 , and a result of sensing by the obstacle sensing unit  43 . 
     When it is determined that at least a partial region of the arm unit  30  is in the close state, the brake control unit  50 H controls the brake unit  41  to restrict actuation of the arm unit  30 . 
     The brake control unit  50 H specifies a joint part  34  that contributes to positional movement of a part of the arm unit  30 , which is determined to be in the close state by the collision determination unit  50 L. For example, assume that the brake control unit  50 H specifies the joint part  34 A and the joint part  34 C. In this case, the brake control unit  50 H controls the brake unit  41 A and the brake unit  41 C to restrict rotation of the specified joint parts  34 A and  34 C. 
     Accordingly, movement of the arm unit  30  due to application of force in the direction of the arrow D 13  is restricted. Specifically, the brake control unit  50 H controls the brake unit  41  based on a result of determination by the collision determination unit  50 L, thereby preventing at least a partial region of the arm unit  30  from colliding with the obstacle B. 
     Then, assume that the worker M further operates the handle part  48  and applies force in the direction of arrow D 14 , which is different from the direction of arrow D 13 , to the grasping part  32  to move the grasping part  32  toward the target position P. 
     In this case, similarly to the above description, the collision determination unit  50 L determines whether the arm unit  30  becomes close to the obstacle B as movement in the direction of the arrow D 14  is continued. In this example, assume a case in which it is determined that the arm unit  30  does not become close to the obstacle B. In this case, the brake control unit  50 H cancels rotation restriction on the joint part  34  rotation of which is restricted. Accordingly, the worker M can move the grasping part  32  in a direction toward the object T while avoiding the obstacle B by continuously applying force in the direction of the arrow D 14  to the grasping part  32 . 
     The collision determination unit  50 L and the brake control unit  50 H execute the same processing in the automatic mode as well in which the arm unit  30  automatically operates as the movement control unit  50 F controls the drive unit  40  provided to each joint part  34  of the arm unit  30 . Accordingly, the object T safely and easily arrives at the target position P in a case in which the arm unit  30  is driven under control of the movement control unit  50 F to move the object T to the target position P, as well. 
     Subsequently, the process of basic work support processing executed by the work support device  10  of the present embodiment will be described below. 
       FIG. 9  is a flowchart illustrating an exemplary flow of the work support processing executed by the work support device  10 . 
     The reception unit  50 E receives mode information indicating the automatic mode or the manual mode from the input unit  46  (step S 100 ). The reception unit  50 E stores the acquired mode information in the storage unit  52  (step S 102 ). 
     The acquisition unit  50 A acquires a target position P from the storage unit  52  (step S 104 ). The target angle derivation unit  50 B derives, by using the target position P acquired at step S 104 , a target angle that is the joint angle of each joint part  34  when the grasping part  32  is positioned at the target position P (step S 106 ). The target angle derivation unit  50 B stores the target angle derived at step S 106  in the storage unit  52  in association with identification information of the corresponding joint part  34  (step S 108 ). 
     Subsequently, movement of the arm unit  30  is started (step S 110 ). When the mode information stored at step S 102  is information indicating the manual mode, movement of the arm unit  30  is disclosed as movement of the grasping part  32  toward the target position P is started through operation of the handle part  48  by the worker M. When the mode information stored at step S 102  is information indicating the automatic mode, movement of the arm unit  30  is disclosed so that the grasping part  32  approaches the target position P as the drive unit  40  is controlled by the movement control unit  50 F. The state determination unit  50 G may determine that movement of the arm unit  30  is started and may execute processing to be described later when a result of detection of the joint angle of the joint part  34 , which is acquired from the corresponding angle sensor  42  by the acquisition unit  50 A, is a detection result indicating temporal change of the joint angle. 
     The joint angle determination unit  50 I determines whether at least one of the joint parts  34  has reached the target angle derived at step S 106  (step S 112 ). At step S 112 , the negative determination (No at step S 112 ) is repeated until the positive determination is obtained (Yes at step S 112 ). When the positive determination is obtained at step S 112  (Yes at step S 112 ), the process proceeds to step S 114 . 
     At step S 114 , the brake control unit  50 H restricts actuation of the joint part  34  determined to have reached the target angle at step S 112  (step S 114 ). 
     Subsequently, the joint angle determination unit  50 I determines whether all joint parts  34  provided to the arm unit  30  each have reached the corresponding target angle derived at step S 106  (step S 116 ). When the negative determination is obtained at step S 116  (No at step S 116 ), the process returns to the above-described step S 112 . When the positive determination is obtained at step S 116  (Yes at step S 116 ), the process proceeds to step S 118 . 
     At step S 118 , the positioning determination unit  50 J specifies the target position P and the relative position of the grasping part  32  with respect to the target position P by performing image analysis of a captured image obtained through image capturing by the target position detection unit  45  (step S 118 ). Then, the positioning determination unit  50 J determines whether the relative position of the grasping part  32  with respect to the target position P coincides with the target position P by using a result of the specification at step S 118  (step S 120 ). 
     When the negative determination is obtained at step S 120  (No at step S 120 ), the process proceeds to step S 122 . At step S 122 , the brake control unit  50 H cancels actuation restriction on all joint parts  34  provided to the arm unit  30  (step S 122 ). Then, the process returns to the above-described step S 112 . 
     When the positive determination is obtained at step S 120  (Yes at step S 120 ), the process proceeds to step S 124 . At step S 124 , the brake control unit  50 H restricts actuation of the brake unit  41  of each joint part  34  provided to the arm unit  30  (step S 124 ). Then, the present routine is ended. 
     The brake control unit  50 H may cancel actuation restriction on all joint parts  34  provided to the arm unit  30  after work by the worker M at the target position P is ended. In this case, the brake control unit  50 H may execute the following processing. 
     For example, assume that a work direction at the target position P is set in advance. In addition, assume that the object T grasped by the grasping part  32  is an electric drill. In this case, the work direction is, for example, a direction in which a hole is formed in a wall by the electric drill. 
     When having determined that pressure in the above-described work direction is applied to the grasping part  32  based on a result of detection of pressure applied to the grasping part  32  and the direction of the pressure, which are acquired from the force sensor  44 , the brake control unit  50 H continues the actuation restriction processing at the above-described step S 124 . When the pressure applied to the grasping part  32  in the above-described work direction is canceled or pressure in another direction is detected based on the detection result, the brake control unit  50 H determines that work by the worker M at the target position P is ended. Then, having determined that the work is ended, the brake control unit  50 H may cancel actuation restriction on all joint parts  34  provided to the arm unit  30 . 
     Subsequently, interrupt processing executed by the work support device  10  during the work support processing illustrated in  FIG. 9  will be described below. 
       FIG. 10  is a flowchart illustrating an exemplary flow of the interrupt processing executed by the work support device  10 . The work support device  10  executes the interrupt processing illustrated in  FIG. 10  during the processing at steps S 112  to S 124  illustrated in  FIG. 9 . 
     The acquisition unit  50 A acquires the set-spatial-region information of the set spatial region E from the storage unit  52  (step S 200 ). The spatial position derivation unit  50 D derives the spatial position of the arm unit  30  by applying the angle of each joint part  34 , which is acquired by the acquisition unit  50 A, to a stereoscopic model of the arm unit  30  that is produced in advance (step S 202 ). 
     Subsequently, the movement direction derivation unit  50 C derives the movement direction of each of the grasping part  32 , the link part  36 B, and the joint parts  34  as components included in the arm unit  30  based on a result of detection of pressure applied to the grasping part  32  and the direction of the pressure, which is acquired from the force sensor  44 , and a result of detection of the joint angle of each joint part  34 , which is acquired from the corresponding angle sensor  42  (step S 204 ). 
     The in-region operation determination unit  50 K determines whether the arm unit  30  is likely to protrude to the outside of the set spatial region E based on the spatial position of the arm unit  30  derived at step S 202 , the movement direction of the arm unit  30  derived at step S 204 , and the set spatial region E of the set-spatial-region information acquired at step S 200  (step S 206 ). 
     When the arm unit  30  is determined to be likely to protrude to the outside of the set spatial region E (Yes at step S 206 ), the process proceeds to step S 208 . 
     At step S 208 , the brake control unit  50 H specifies a joint part  34  that contributes to positional movement of a region of each part included in the arm unit  30 , which is determined to be likely to protrude to the outside of the set spatial region E at step S 206 . Then, the brake control unit  50 H controls the corresponding brake unit  41  to restrict actuation of the specified joint part  34  (step S 208 ). Then, the process returns to the above-described step S 202 . 
     When the arm unit  30  is determined not to likely to protrude to the set spatial region E at step S 206  (No at step S 206 ), the process proceeds to step S 210 . 
     At step S 210 , the brake control unit  50 H cancels actuation restriction on the joint part  34  actuation of which is restricted (step S 210 ). 
     Subsequently, the collision determination unit  50 L acquires an obstacle sensing result from the obstacle sensing unit  43  (step S 212 ). Then, the collision determination unit  50 L determines whether the arm unit  30  is close to the obstacle B based on the obstacle sensing result and the movement direction of the arm unit  30 , which is derived at step S 204  (step S 214 ). 
     When it is determined that the arm unit  30  is close to the obstacle B (Yes at step S 214 ), the process proceeds to step S 216 . At step S 216 , the brake control unit  50 H specifies a joint part  34  that contributes to positional movement of a part of the arm unit  30  determined to be in the close state by the collision determination unit  50 L. Then, the brake control unit  50 H controls the corresponding brake unit to restrict actuation of the specified joint part (step S 216 ). Then, the process returns to the above-described step S 202 . 
     When it is determined that the arm unit  30  is not close to the obstacle B (No at step S 214 ), the process proceeds to step S 218 . At step S 218 , the brake control unit  50 H cancels actuation restriction on the joint part  34  actuation of which is restricted (step S 218 ). Then, the present routine is ended. 
     As described above, the work support device  10  of the present embodiment includes the arm unit  30 , each brake unit  41 , the state determination unit  50 G, and the brake control unit  50 H. The arm unit  30  includes the grasping part  32  grasping the object T, the joint parts  34 , and the link parts  36  actuatably coupled through the joint parts  34 . The brake unit  41  is provided to at least one of the joint parts  34  to restrict actuation of the arm unit  30 . The state determination unit  50 G determines the arm state of the arm unit  30 . The brake control unit  50 H controls the brake unit  41  to restrict actuation of the arm unit  30  in accordance with the arm state. 
     In this manner, the work support device  10  of the present embodiment controls the brake unit  41  provided to the arm unit  30  in accordance with the arm state of the arm unit  30 , to restrict actuation of the arm unit  30 . 
     Thus, the work support device  10  of the present embodiment can achieve improved work support. 
     Subsequently, an exemplary hardware configuration of the control unit  20  in the work support device  10  of the above-described embodiment will be described below. 
       FIG. 11  is a diagram illustrating an exemplary hardware configuration of the control unit  20 . 
     The control unit  20  has a hardware configuration of a typical computer including a control device such as a CPU  86 , storage devices such as a read-only memory (ROM)  88 , a random-access memory (RAM)  90 , and a hard disk drive (HDD)  92 , an I/F unit  82  that is an interface for various devices, and a bus  96  connecting the components. 
     In the control unit  20  of the above-described embodiment, each of the above-described components is implemented on the computer when the CPU  86  reads a computer program from the ROM  88  onto the RAM  90  and executes the computer program. 
     A computer program for executing the above-described processing executed by the control unit  20  of the above-described embodiment may be stored in the HDD  92 . The computer program for executing each above-described processing executed by the control unit  20  of the above-described embodiment may be incorporated in the ROM  88  in advance and provided. 
     The computer program for executing the above-described processing executed by the control unit  20  of the above-described embodiment may be stored in a computer-readable storage medium such as a CD-ROM, a CD-R, a memory card, a digital versatile disc (DVD), or a flexible disk (FD) as a file in an installable or executable format to be provided as a computer program product. The computer program for executing the above-described processing executed by the control unit  20  of the above-described embodiment may be stored on a computer connected with a network such as the Internet, and downloaded and provided through the network. The computer program for executing the above-described processing executed by the control unit  20  of the above-described embodiment may be provided or distributed through a network such as the Internet. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.