JP6557945B2 - Robot, robot system and control device - Google Patents

Description

  The present invention relates to a robot, a robot system, and a control device.

  An industrial robot provided with a hand having a plurality of fingers is known (see Patent Document 1). In Patent Document 1, the object is grasped by sandwiching the object whose position and orientation are recognized by a camera or the like with a plurality of fingers. Furthermore, by controlling the position of the hand that holds the object, it is possible to realize operations such as press-fitting the object into the product.

JP 2012-139808 A

  However, when the position of the object cannot be accurately recognized by a camera or the like, there is a problem that the relative position of the object with respect to the hand when grasped becomes inaccurate. Further, if the position where the object is gripped with respect to the hand becomes inaccurate, it becomes impossible to normally perform operations such as press-fitting the object into the product by controlling the posture of the hand.

  The present invention has been made in view of at least one of the above problems, and provides a robot, a robot system, and a control device that can grip an object at an accurate position with respect to a hand unit.

  (1) The robot of the present invention is made to solve the above-described problem, includes a hand unit having a plurality of fingers, and sandwiches an object by bringing the plurality of fingers closer to the first axis direction. The state where the plurality of fingers are separated in the first axis direction to release the object is released, and the plurality of fingers are moved closer to the second axis direction to hold the object.

  Thus, before gripping the object, the plurality of fingers are moved close to the first axis in advance to sandwich the object, so that the plurality of fingers when the object is sandwiched in the first axis direction. The object can be positioned based on the position. Therefore, the position and direction (second axis direction) for gripping the object by approaching the plurality of fingers based on the positions of the plurality of fingers when the object is sandwiched in the first axis direction can be determined. The object can be gripped at an accurate position.

  (2) Further, the present invention is the robot according to (1), wherein the plurality of fingers are four fingers, and when the plurality of fingers move in the first axis direction, The positions of the two fingers may match in the first axis direction, and the positions of the other two fingers of the plurality of fingers may match in the first axis direction. In the above configuration, the object can be supported from one side in the first axial direction by two fingers having the same position in the first axial direction, so that the object can be positioned in a stable posture. In particular, since the positions of two fingers coincide in the first axis direction and the positions of the other two fingers coincide in the first axis direction, the fingers are brought into contact with two parallel planes. By sandwiching the object, the object can be positioned in a stable posture.

  (3) A robot system according to the present invention includes a hand unit having a plurality of fingers, sandwiches an object by bringing the fingers close to each other in the first axis direction, and separates the plurality of fingers in the first axis direction. And a control device that controls the hand unit so as to release the state in which the object is sandwiched and bring a plurality of fingers closer to the second axis to grip the object. Even in the robot system configured as described above, an object can be gripped at an accurate position with respect to the hand unit.

  (4) A robot control apparatus according to the present invention is a control apparatus that controls a robot including a hand unit having a plurality of fingers, the plurality of fingers approaching in the first axis direction, and an object is sandwiched between the plurality of fingers. The hand unit is controlled so as to release the state in which the object is sandwiched by separating the fingers in the first axis direction, and to grip the object by moving the plurality of fingers in the second axis direction. Even in the robot control apparatus configured as described above, an object can be gripped at an accurate position with respect to the hand unit.

  The functions of the constituent elements recited in the claims are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of these components are not limited to those realized by hardware resources that are physically independent of each other. Furthermore, the present invention can be realized as a robot system including a control device, a robot control device, a robot control program, or a recording medium for the robot control program. Of course, the recording medium for the computer program may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium that will be developed in the future.

The front view concerning embodiment of this invention. (2A) (2B) is a side view according to the embodiment of the present invention, and (2C) to (2E) are plan views according to the embodiment of the present invention. The block diagram concerning embodiment of this invention. The flowchart concerning embodiment of this invention. The flowchart concerning embodiment of this invention. (6A) to (6C) are plan views according to an embodiment of the present invention, and (6D) to (6F) are plan views according to another embodiment of the present invention. The front view concerning embodiment of this invention. (8A)-(8C) is a side view according to an embodiment of the present invention, and (8D) is a plan view according to another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.

1. Overview FIG. 1 is a diagram illustrating an example of a usage status of a robot system 1 according to an embodiment of the present invention. The robot system 1 includes a robot 9 and a control device 40. The control device 40 is communicably connected to the robot 9. This connection conforms to, for example, wired communication standards such as Ethernet (registered trademark) and USB (Universal Serial Bus), and wireless communication standards such as Wi-Fi (registered trademark). The robot 9 includes an imaging unit 10, hand units 20 a and 20 b, and a body unit 30. That is, the robot 9 is a double-arm robot including two hand units 20a and 20b.

  The robot 9 acquires a control signal based on the three-dimensional position and orientation of the object O from the control device 40, and performs a predetermined operation on the object O based on the acquired control signal. The predetermined work is, for example, that the object O is grasped by the hand unit 20 and the grasped object O is moved from the currently installed position to another position, or after the movement, For example, assembling the device. In the present embodiment, an operation for fitting four types of objects O1, O2, O3, and O4 randomly placed on the work table S into one set will be described. The objects O1, O2, O3, and O4 are objects in which grooves and pins having different shapes are provided at different positions on one surface of a rectangular parallelepiped block having the same shape, and two predetermined pieces are correctly fitted. Assume that a substantially cubic block is assembled.

2. Configuration The imaging unit 10 is provided in the upper part of the body unit 30. The imaging unit 10 includes, for example, cameras 11a and 11b each including a lens and an imaging element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). In this embodiment, the imaging unit 10 is described as a robot system using a stereo camera constituted by two cameras 11a and 11b. However, the imaging unit may be constituted by three or more cameras. Alternatively, a two-dimensional image may be captured by a single camera. The objects O to be operated by the robot system 1 are randomly placed within the field angle range on the work table S that can be imaged by the imaging unit 10. The imaging unit 10 captures the target object O placed on the work table S or the target object O held by the hand unit 20, and the captured image of the target object O is communicated to the control device 40. Output.

  The hand unit 20 is connected to the upper two portions of the body unit 30. The hand unit 20 includes an arm 21 having at least a three-axis link and a hand 22 connected to the tip of the arm 21 with a single-axis degree of freedom. Each axis of the hand unit 20 is driven by an actuator (not shown). The hand units 20 a and 20 b include a force sensor (not shown) between each hand 22 and the arm 21. This makes it possible to perform cooperative control of both arms using impedance control. The force sensor includes a piezoelectric body. For example, by using a quartz crystal as a piezoelectric body, it becomes difficult to be influenced by temperature, and an external force can be accurately detected.

  2A and 2B are side views of the hand 22, and FIGS. 2C to 2E are front views of the hand 22. The hand 22 includes a palm part 221 and four fingers 222 a to 222 d, and the fingers 222 a to 222 d are connected to the palm part 221. The palm unit 221 is configured to move the palm 2211 in the reference direction and move the fingers 222a to 222d in the first movement direction and the second movement direction. The reference direction is a direction orthogonal to the plate-like palm 2211 and substantially coincides with the length direction of the arm 21 in the extended state. The first movement direction and the second movement direction are orthogonal to each other and also orthogonal to the reference direction. 2A and 2B are views of the hand 22 viewed from the first movement direction, and FIGS. 2C to 2E are views of the hand 22 viewed from the reference direction.

  The palm unit 221 includes a palm 2211, a fixed driving unit 2212, two movable driving units 2213 a and 2213 b, and a base 2214. The base portion 2214 is fixed to a connecting shaft with the arm 21, and a fixed drive portion 2212 is fixed to the base portion 2214. The fixed drive unit 2212 is an actuator that drives the palm 2211 and the movable drive units 2213a and 2213b based on a control signal output from the control device 40. As shown in FIGS. 2A and 2B, the fixed drive unit 2212 is connected to the palm 2211 via the connecting shaft T1, and the palm 2211 is moved in the reference direction by changing the length of the connecting shaft T1 protruding in the reference direction. Move to.

  As shown in FIGS. 2C and 2E, the fixed drive unit 2212 is connected to each of the movable drive units 2213a and 2213b via the connection shaft T2, and the length of the connection shaft T2 protruding in the first movement direction is changed. As a result, the movable drive units 2213a and 2213b are moved in the first movement direction. The direction in which the connecting shafts T2 of the movable drive units 2213a and 2213b extend is the opposite direction in the first movement direction, and the length in which the connection shafts T2 of the movable drive units 2213a and 2213b extend in the first movement direction is the same. is there.

  The movable drive units 2213 a and 2213 b are actuators that drive the fingers 222 a to 222 d based on a control signal output from the control device 40. The movable drive unit 2213a is connected to each of the fingers 222a and 222b via the connecting shaft T3, and the fingers 222a and 222b are moved to the second position by changing the length of the connecting shaft T3 protruding in the second moving direction. Move in the direction. The second movement direction is a direction orthogonal to the first movement direction. The direction in which the connection axes T3 of the fingers 222a and 222b extend is opposite to the second movement direction, and the length of the connection axes T3 of the fingers 222a and 222b in the second movement direction is the same. The movable drive unit 2213b is connected to each of the fingers 222c and 222d via the connecting shaft T3, and the fingers 222c and 222d are moved in the second moving direction by changing the length of the connecting shaft T3 extending in the second moving direction. Move to. The direction in which the connection axes T3 of the fingers 222c and 222d extend is the opposite direction in the second movement direction, and the length of the connection axes T3 of the fingers 222c and 222d in the second movement direction is the same.

  As shown in FIGS. 2C and 2D, the fixed driving unit 2212 moves the movable driving units 2213a and 2213b (non-driving), thereby moving the fingers 222a to 222d in the first movement direction. As shown in FIGS. 2C and 2E, when the fixed drive unit 2212 is not driven, the movable drive units 2213a and 2213b are driven to move the fingers 222a to 222d in the second movement direction. Of the fingers 222a to 222d, the positions of the two fingers 222a and 222b always coincide with each other in the first movement direction, and among the fingers 222a to 222d, the positions of the other two fingers 222c and 222d are in the first movement direction. Always match. Of the fingers 222a to 222d, the positions of the two fingers 222a and 222d always coincide with each other in the second movement direction, and among the fingers 222a to 222d, the positions of the other two fingers 222b and 222c are in the second movement direction. Always match.

  Next, the hardware configuration of the control device 40 will be described with reference to FIG. 3A. The control device 40 includes, for example, a CPU (Central Processing Unit) 41, a storage unit 42, an input receiving unit 43, and a communication unit 44, and communicates with the robot 9 via the communication unit 44. These components are connected to the bus Bus via an input / output mechanism (not shown) so that they can communicate with each other. The CPU 41 executes various programs stored in the storage unit 42. The storage unit 42 includes, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a ROM (Read-Only Memory), a RAM (Random Access Memory), and the like. Various information, images, and programs processed by the control device 40 are stored. The storage unit 42 may be an external storage device connected by a digital input / output port such as a USB instead of the one built in the control device 40.

  The input receiving unit 43 is, for example, a keyboard, mouse, touch pad, or other input device. The input receiving unit 43 may function as a display unit, and may be configured as a touch panel. The communication unit 44 includes, for example, a digital input / output port such as USB, an Ethernet port, and the like.

  Next, the functional configuration of the control device 40 will be described with reference to FIG. 3B. The control device 40 controls the robot 9 to perform a predetermined work. More specifically, the control device 40 derives the three-dimensional position and orientation of the object O based on the image captured by the imaging unit 10. Then, the control device 40 holds the object O with the hand unit 20 based on the derived three-dimensional position and orientation of the object O. Then, the control apparatus 40 moves the target object O with the hand unit 20 to the position and attitude | position which are easy to recognize using the image imaged with the imaging part 10. FIG. Subsequently, the control device 40 captures the object O by the imaging unit 10 and recognizes whether the object O is the object O1, O2, O3, or O4 by template matching with the captured image. Thereafter, the control device 40 fits two predetermined objects Ox and Oy with the hand unit 20a. Therefore, the control device 40 includes an image acquisition unit M1, an image recognition unit M2, and a hand unit control unit M3. Some or all of these functional units are realized by, for example, the CPU 41 executing various programs stored in the storage unit 42. Some or all of these functional units may be hardware functional units such as LSI (Large Scale Integration) and ASIC (Application Specific Integrated Circuit).

  The image acquisition unit M1 acquires an image captured by the imaging unit 10, and outputs the acquired image to the image recognition unit M2. The image acquisition unit M1 may store the acquired image in the storage unit 42, and the image recognition unit M2 may read the image from the storage unit 42. The image recognition unit M2 derives the three-dimensional position and orientation of the object O based on the image acquired from the image acquisition unit M1, and the object O is any of the objects O1, O2, O3, and O4. Recognize. Then, the image recognition unit M2 outputs the derived three-dimensional position and orientation of the object O to the hand unit control unit M3. The hand unit control unit M3 outputs a control signal for controlling the hand unit 20 based on the output of the image recognition unit M2.

3. Robot Control Method Next, an outline of a robot control method in the robot system 1 will be described with reference to FIG. 4A. Here, in a state where the four objects O are randomly placed on the work table S, the two predetermined objects O1 and O2 are gripped and fitted, and another predetermined two are determined. A sequence for causing the robot 9 to perform the operation of fitting the two objects O3 and O4 will be described.

  First, the control device 40 acquires images on the work table S from the imaging unit 10 and specifies the positions and postures of the four objects O placed on the work table S (S1). Specifically, the image recognition unit M2 recognizes the approximate contour of the object O based on the image acquired from the imaging unit 10, and based on the recognized approximate contour, the posture of the work object O in the approximate position. Determine if it is on S. The approximate contour recognized by the image recognition unit M2 is a closed curve that forms a silhouette of an object when the camera 11a is assumed to be a light source. By specifying the general posture of the object O in this way, the object O can be reliably gripped by the hand 22. Further, one or more templates that are highly likely to correspond to the object O to be actually gripped are selected from the templates stored for each object O, or the templates stored for each posture of the object O are stored. From this, one or more templates that are highly likely to correspond to the posture of the object O when it is actually imaged are selected, or the object O is rolled to change the posture before being gripped. It is also possible to reduce the time and the amount of processing required to recognize. At this stage, it is not necessary to recognize whether each of the four objects O is the object O1, O2, O3, or O4, and it is not necessary to specify the exact posture of the object O. Although the positions and postures of the four objects O are specified using the three-dimensional image, the positions and postures of the four objects O may be specified using a three-dimensional object recognition technique.

  Next, the control device 40 sets one of the four objects O as the object OU to be recognized (S2). At this stage, it is unknown whether the target object OU set here is the target object O1, O2, O3, or O4. Hereinafter, the target object OU is different from the other three target objects O. Separately written.

  Next, the control device 40 executes a process (gripping process) for gripping the object OU with the one hand unit 20b (S3).

  Next, the control device 40 executes a re-gripping process for reliably bringing the grasped object OU into contact with three or more points that are not on the same straight line of the palm 2211 (S4). Here, when the palm 2211 contacts three or more points that are not on the same straight line, the posture of the object O is determined only by the palm 2211. If the object O is gripped in a state where the object O is in contact with three or more points that are not on the same straight line of the palm 2211, the posture of the object O more reliably corresponds to the posture of the palm 2211. Note that contacting with three or more points of the palm 2211 includes contacting the palm 2211 and the object O with a surface.

  Next, the control device 40 executes recognition processing S5 for recognizing which of the objects O1, O2, O3, and O4 is the re-held object OU (S5).

Next, the control device 40 returns the object OU onto the work table S (S6). Specifically, the object OU is returned with the hand 20b to the position and posture where the object OU was placed on the work table S before the object OU is held with the hand 20b. For this reason, if the position and posture previously placed on the work table S are specified in step S1, the position and posture of the object O on the work table S are specified each time the hand unit 20 is to be gripped. There is no need to do.
Next, the control device 40 determines whether or not all four objects O have been recognized (S7). If all the objects O are not recognized, the setting of the object O to be recognized is changed and the above-described processing is repeated from step S2.

  If all the objects O are recognized, the control device 40 then selects a predetermined two of the four objects O1, O2, O3, O4 as a pair of objects Ox, Set as Oy (S8).

  Next, the control device 40 executes a process of grasping the object Ox (gripping process (left)) using one (left side) hand unit 20a (S9).

  Next, the control device 40 executes a re-gripping process (left) for reliably bringing the grasped object Ox into contact with three or more points that are not on the same straight line of the palm 2211 of the hand unit 20a (S10).

  Next, the control device 40 executes a process (gripping process (right)) for gripping the object Oy using the other (right) hand unit 20b (S11).

  Next, the control device 40 executes a re-gripping process (right) for reliably bringing the grasped object Oy into contact with three or more points that are not on the same straight line of the palm 2211 of the hand unit 20b (S12).

  Next, the control device 40 executes a fitting process for fitting the object Ox gripped by the hand unit 20a and the object Oy gripped by the hand unit 20b (S13).

  Next, the control device 40 determines whether or not all the objects O1, O2, O3, and O4 have been fitted (S14). When all the objects O1, O2, O3, and O4 are not fitted, the control device 40 changes the setting of the objects to be fitted Ox and Oy and repeats the process from step S8 described above. When all the objects O1, O2, O3, and O4 are fitted, the fitting work is completed.

(Gripping process)
Next, the gripping process will be described with reference to FIG. 4B. Note that the control methods in the above-described gripping process in step S2, gripping process in step S9 (left), and gripping process in step S11 (right) are substantially the same except that the driven hand unit 20 is different.

  First, the control device 40 drives the arm 21 to move the hand 22 vertically above the object O set as a recognition target or a fitting target (S101). For example, in the control device 40, the connecting shaft T1 that connects the palm 2211 to the fixed drive unit 2212 is in the vertical direction, the object O is positioned below the extension line of the connecting shaft T1, and the object O and the palm 2211 are connected. The arm 21 is driven so that the distance between and becomes a predetermined distance. Next, the control device 40 moves the hand 22 until the palm 2211 comes into contact with the object O (S102). Specifically, the control device 40 moves the hand 22 downward until a force sensor (not shown) provided in the hand 22 detects contact between the palm 2211 and the object O. Next, the control device 40 separates the hand 22 vertically upward from the object O by a predetermined distance (S103). Specifically, since the position where the palm 2211 has contacted the object O is found in step S102, the hand 22 is vertically moved in a range where the tips of the fingers 222a to 222d are positioned at positions lower than the contacted position. Move upward.

  Next, the control device 40 causes the fingers 222a to 222d to approach the first axis and pinches the object O (S104). FIG. 6A is a schematic diagram illustrating a state in which the fingers 222a to 222d sandwich the object O in step S104. The first axis direction is a direction determined based on the posture of the object O specified in step S1, and in the example of FIG. 6A, a direction orthogonal to a pair of parallel surfaces of the object O having a rectangular shape in plan view. Is set as the first axis direction. In the example of FIG. 6A, the posture of the hand 22 is controlled so that the first axis direction matches the second movement direction of the fingers 222a to 222d of the hand 22 in any of steps S101 to S103. Therefore, bringing the fingers 222a to 222d closer to the second movement direction means bringing the fingers 222a to 222d closer to the first axis direction. Controlling the posture of the hand 22 includes controlling the posture of the arm 21 and rotating the hand 22 with respect to the arm 21. In step S104, the positions of the two fingers 222a and 222d of the fingers 222a to 222d always coincide with each other in the first axis direction, and the positions of the other two fingers 222b and 222c of the fingers 222a to 222d. Always match in the first axis direction. For example, the control device 40 outputs a control signal for causing the fingers 222a to 222d to approach the first axis at a predetermined speed continuously for a predetermined period to the hand 22, and when the predetermined period ends, the fingers 222a to 222d It may be considered that the object O is sandwiched in one axial direction. The predetermined period may be a period during which the entire movable region can be moved when the fingers 222a to 222d are moved in the first axis direction at a predetermined speed, for example. As shown in FIG. 6A, the movement of the fingers 222a to 222d stops with the fingers 222a to 222d sandwiching the object O in the first axis direction, but the position x1 of the two fingers 222a and 222d and the other The object O can be centered at the center position x0 of the positions x2 of the two fingers 222b and 222c. Further, as shown in FIG. 6A, since the two fingers 222a and 222d and the other two fingers 222b and 222c press the plane of the object O, variations in the posture of the object O can be suppressed.

  Next, the control device 40 releases the state in which the fingers 222a to 222d are spaced apart in the first axial direction and the object O is sandwiched therebetween (S105). FIG. 6B is a schematic diagram illustrating a state in which the state in which the fingers 222a to 222d sandwich the object O is released in step S105. For example, from the state of step S140, the fingers 222a to 222d are moved in the first axial direction so that the distance between the two fingers 222d and 222c and the other two fingers 222a and 222b is increased by a predetermined distance. That's fine.

  Next, the control device 40 causes the fingers 222a to 222d to approach the second axis and grips the object O (S106). FIG. 6C is a schematic diagram illustrating how the fingers 222a to 222d hold the object O in step S106. In the present embodiment, the second axis direction is a direction orthogonal to the first axis direction (second movement direction). In steps S104 to S106, in order to keep the position and direction of the hand 22 constant, the second axis direction and the first movement direction coincide. Therefore, the control device 40 causes the fingers 222a to 222d to approach in the second axis direction by causing the fingers 222a to 222d to approach in the first movement direction, and grips the object O.

  As described above, in step S104, the object O can be centered at the center position x0 between the position x1 of the two fingers 222a and 222d and the position x2 of the other two fingers 222b and 222c. With reference to the centered position x0, the positions x3 and x4 in the first axis direction where the fingers 222a to 222d hold the object O can be optimized. Furthermore, when the fingers 222a to 222d approach the second axis direction and grip the object O, the object O can be centered also in the second axis direction. Thereby, the object O can be gripped at an accurate position with respect to the hand 22.

(Re-gripping process)
Next, the re-gripping process will be described with reference to FIG. 5A. The control method in the above-described re-gripping process in step S4, re-gripping process in step S10 (left), and re-gripping process in step S12 (right) is substantially the same except that the driving hand unit 20 is different. It is.

  First, the control device 40 moves the hand 22 until the object O is positioned vertically above the palm 2211 (S201). Specifically, for example, the control device 40 starts from a state in which the connecting shaft T1 of the palm 2211 is below the palm 2211, and the connecting shaft T1 is positioned above the palm 2211 as shown in FIG. The arm 21 is driven to move the hand 22 so that the axis T1 is parallel to the vertical direction.

  Next, the control device 40 releases the object O from the state held by the fingers 222a to 222d by reducing the gripping force of the object O by the fingers 222a to 222d (S202). Specifically, for example, the object O may be released by separating the fingers 222a to 222d in the first axis direction and the second axis direction until the fingers 222a to 222d are separated from the object O. Further, for example, the gripping force of the fingers 222a to 222d is reduced to the extent that the object O slides due to its own weight with respect to the fingers 222a to 222d in a state where the object O and the fingers 222a to 222d are in contact with each other. May be. When the object O is released, the object O moves due to gravity and stops in contact with the palm 2211. That is, when the state in which the object O is sandwiched is released, the posture of the object O follows the posture of the palm 2211 and the posture of the palm 2211 corresponds to the posture of the object O.

  When releasing the object O from the fingers 222a to 222d, the object O rotates and the posture of the object 22 becomes easier to follow the posture of the palm 2211 as the distance between the fingers 222a to 222d is increased. Depending on the shape, the possibility that the object O falls from between the fingers 222a to 222d increases. Therefore, it is desirable to set the moving distance of the fingers 222a to 222d in step S202 according to the shape of the object O.

  Next, the control device 40 increases the gripping force of the object O with the fingers 222a to 222d, thereby gripping the object O with the fingers 222a to 222d again (S203). As a result, the object O can be gripped by the hand 22 in a state in which the posture of the object O follows the posture of the palm 2211.

  In the re-gripping process, the object O is brought into contact with three or more points that are not on the same straight line of the palm 2211 so that the object O is re-established in a state in which the posture of the object O is surely matched to the posture of the palm 2211. Need to grip. Therefore, after the object O is brought into contact with the palm 2211 by gravity, the gripping force of the fingers 222a to 222d is increased, and then the gripping force of the fingers 222a to 222d is decreased again and released. The object O may be securely held in contact with three or more points that are not on the same straight line of the palm 2211, and thereafter, the gripping force of the fingers 222a to 222d may be increased again and held. Thereby, for example, even when the object O moves with respect to the palm 2211 when the object O in contact with the palm 2211 is gripped by the fingers 222a to 222d, the object O is not again on the same straight line of the palm 2211. It is possible to make contact more than the point. When the gripping force of the fingers 222a to 222d is reduced again, the distance between the fingers 222a to 222d and the object is shorter than when the object O is released by first reducing the gripping force of the fingers 222a to 222d. It is preferable to release the object in range.

(Recognition process)
Next, the recognition process will be described with reference to FIG. 5B. Here, the process of holding and recognizing the object OU by the hand unit 20b and returning the recognized object OU onto the work table S is repeated, but all the objects O are alternately used by using the hand units 20a and 20b. May be recognized by grasping all the objects O by repeatedly using either one of the hand units 20a and 20b.

  First, the control device 40 drives the hand unit 20b to move the object OU to a predetermined posture at a predetermined position on the optical axis of the camera 11b (S301). That is, the control device 40 moves the object OU to a predetermined position and posture with reference to the camera 11b. Specifically, as shown in FIG. 7A, the control device 40 drives the hand unit 20b, so that the object OU moves to a position closer to the camera 11a than the state placed on the work table S, The object OU is moved so that the connecting axis T1 of the palm 2211 overlaps the optical axis of the camera 11a. At this time, since the posture of the object OU may be regarded as following the posture of the palm 2211, it is not necessary to perform image recognition in order to recognize the posture of the object O. That is, since the specific posture of the palm 2211 corresponds to the predetermined position of the object OU and the specific posture of the palm 2211 corresponds to the predetermined posture of the target object OU, the control device 40 determines the specific position and specific posture of the palm 2211. The object O can be moved to a predetermined posture at a predetermined position simply by setting the target and performing feedback control of the hand unit 20b. Then, by bringing the object OU closer to the camera 11a, the object OU can be enlarged and imaged. Further, by bringing the object OU closer to the optical axis of the camera 11a, the object OU can be imaged without distortion corresponding to the template. The object OU may be imaged using the camera 11b, or the object OU may be imaged using both the cameras 11a and 11b.

  Next, the control device 40 executes template matching for matching the image of the object OU with four templates stored in advance (S302). Specifically, the control device 40 first acquires an image of the object OU in a predetermined posture at a predetermined position captured by the camera 11 a by controlling the imaging unit 10. Next, the control apparatus 40 extracts the outline of the object OU by analyzing the image of the object, and collates the extracted outline with four templates stored in advance. Each of the four templates collated with respect to the contour is the surface of the object O1, O2, O3, O4 that faces the other object O when mated with another object O to be mated ( The fitting surface) may be prepared in advance based on images captured by the camera 11a from the front.

Next, the control device 40 determines whether or not the image of the object OU has been successfully matched with any template (S303).
When matching of the image of the object OU with any template is successful, that is, any of the fitting surfaces of the objects O1, O2, O3, and O4 faces the camera 11a in the recognition process. When the object OU is gripped, the control device 40 recognizes and identifies whether the target object OU is the target object O1, O2, O3, or O4 according to the template that can be collated, and is gripped. The posture of the object OU in the state where it was previously placed on the work table S is specified and stored.

  When the image of the object OU cannot be collated with any template, the control device 40 determines whether or not the template matching in step S302 has been executed twice for the object OU (S305).

  When the template matching of step S302 is not executed twice for the object OU, that is, when the template matching is executed only in a state of being held by the hand unit 20b that is one of the two hand units 20, The control device 40 changes the object OU from the hand unit 20b to the hand unit 20a (S306). Specifically, the control device 40 drives the hand unit 20a and the hand unit 20b so that the connection axis T1 of the palm 2211 of the hand unit 20b and the connection axis T1 of the palm 2211 of the hand unit 20a are aligned. . Subsequently, the control device 40 holds the object OU held by the hand unit 20b with the hand unit 20a. Subsequently, the control device 40 causes the hand unit 20b to release the object OU held by the hand unit 20a.

  As described above, when the second template matching is executed, the object OU is transferred from one hand unit 20b to the other hand unit 20a between the first template matching and the second template matching. The position and orientation of the object OU with respect to the camera 11 are different between the first template matching and the second template matching. Specifically, the second surface corresponding to the back side of the first surface of the object OU that is imaged facing the camera 11 in the first template matching is imaged facing the camera 11 in the second template matching. . In the second template matching, the object OU is preferably imaged by the other camera 11b. Thereby, the hand unit 20a necessary for moving the object OU from the first predetermined position and posture for the first template matching to the second predetermined position and posture for the second template matching, The driving amount of 20b can be suppressed.

  Next, the control device 40 executes the re-grip processing of the object OU for the hand unit 20a (S307).

  When the template matching in step S302 is executed twice for the object OU, that is, four images obtained by capturing the object OU regardless of whether it is gripped by the hand unit 20a or the hand unit 20b. When matching with none of the certain templates is successful, the control device 40 drives the hand unit 20a to roll the object OU onto the work table S (S308). As a result, the posture in which the object OU is placed on the work table S is highly likely to change from the state before the object OU is gripped. When the object OU is rolled on the work table S in this way, the position and orientation of all the four objects O placed on the work table S may change. The process is redone from the above process.

(Mating process)
Next, the fitting process will be described with reference to FIG. 5C.
First, the control device 40 drives the hand units 20a and 20b, thereby causing the object Ox gripped by the hand 22a and the object Oy gripped by the hand 22b to each have a predetermined mating position at a predetermined mating position. (S401). The fitting position and the fitting posture may be determined in advance according to the shapes of the objects Ox and Oy. In this embodiment, the connecting posture T1 of the palm 2211 of the hand 22a that holds the object Ox and the connecting axis T1 of the palm 2211 of the hand 22b that holds the object Ox are aligned in a straight line. Shall be determined.

Next, the control device 40 reduces the force with which the two hands 22a and 22b grip the objects Ox and Oy to such an extent that the objects Ox and Oy slide relative to the fingers 222a to 222d (S402).
Next, the control device 40 drives the two hand units 20a and 20b so as to press the two objects Ox and Oy together (S403). Specifically, the control device 40 drives the hand units 20a and 20b so that the connecting shaft T1 of the palms 2211 of the two hands 22a and 22b approaches in a straight line. As a result, even if one of the objects Ox and Oy is gripped in a state where it is not in contact with the three points of the palm 2211, the state is canceled, so both the objects Ox and Oy are respectively It will be in the state which contacted 3 points | pieces of the palm 2211 reliably.

  Next, the control device 40 causes the object Ox and the object Oy to be fitted by moving the hand unit 20 in a predetermined fitting sequence (S404). The fitting sequence may be determined in advance by combining parallel movement and rotation according to the shapes of the object Ox and the object Oy.

Next, the control device 40 drives one hand unit 20a to release the object Ox from the hand 22a (S405).
Next, the control device 40 drives the other hand unit 20b to place the fitted objects Ox and Oy on the work table S.

4). Effect According to the embodiment described above, the object O can be imaged and recognized at a position and posture with high recognition accuracy, and therefore the recognition accuracy of the objects OU randomly placed on the work table S can be improved. . Furthermore, since the object OU can be imaged large and the object OU can be imaged without distortion with respect to the template, the recognition accuracy of the object OU can be improved.
Further, even when the first hand unit 20a holds the object OU in a state where the outline of the object OU corresponding to the template is hidden by the finger 222 or the palm 221, the object OU is moved to the second hand unit 20b. Accordingly, the object OU can be recognized by imaging the contour corresponding to the template. Further, as compared with the case where the object OU is once returned to the work table S and is held by the same hand unit 20a, the time and processing amount required to recognize the object OU can be reduced.

  Then, in order to recognize the general outline of the target object OU imaged by the camera 11 before the hand unit 20a grips the target object OU, the target object OU actually gripped from the template stored for each target object O is recognized. It is highly possible to select one or more templates that are highly likely to correspond to the target object, or to correspond to the posture of the target object OU when it is actually imaged from templates stored for each posture of the target object OU. It is also possible to select one or more templates, or roll the object OU before holding it to change the posture, thereby reducing the time and processing amount required to recognize the object OU.

Further, since the posture of the object O follows the posture of the palm 2211 and the posture of the palm 2211 corresponds to the posture of the object O, the posture of the object O can be reliably controlled with simple processing. For example, the posture of the object O can be reliably controlled without executing the three-dimensional object recognition in the process of moving the object O to a posture with high recognition accuracy. Further, when the posture of the object O is imitated with the posture of the palm 2211, the object O is moved by gravity, and therefore the actuator for moving the palm 2211 is omitted, and the configuration of the hand unit 20 can be simplified. Is possible.
Further, since the hand unit 20 can accurately grasp the object O in a posture that follows the palm 2211, the two objects Ox and Oy can be accurately fitted by cooperative control.

  In step S104, the object O can be centered at the center position x0 between the position x1 of the two fingers 222a and 222d and the position x2 of the other two fingers 222b and 222c. With reference to the centered position x0, the positions x3 and x4 in the first axis direction where the fingers 222a to 222d hold the object O can be optimized. Furthermore, when the fingers 222a to 222d approach the second axis direction and grip the object O, the object O can be centered also in the second axis direction. Thereby, the object O can be gripped at an accurate position with respect to the hand 22.

5. Other Embodiments The technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.
For example, when the object OU is moved to a predetermined position and posture with respect to the camera 11 in order to recognize the object OU, the posture of the object OU is moved while recognizing the posture of the object OU using a three-dimensional object recognition technique. May be.

  Further, for example, when the second template matching is executed to recognize the object OU, instead of holding the object OU with the two hand units 20 and moving the object OU to the second predetermined posture, The posture of the object OU may be moved to the second predetermined posture.

  Further, for example, before the posture of the object O is made to follow the posture of the palm 2211, the palm 2211 is moved by the fixed drive unit 2212 from the state shown in FIG. 8A, and the palm 2211 is moved to the object O as shown in FIG. 8B. You may make it approach. Thereby, when the gripping force of the finger 222 is weakened and the object O is released as shown in FIG. 8C, the object O can be prevented from slipping through the plurality of fingers 222 and falling from the hand 22. Further, the object O can be prevented from being damaged by an impact when the object O collides with the palm 2211.

  Further, for example, a suction port 2211b for sucking the object O to the palm 2211 may be provided as shown in FIG. 8D. In this case, by sucking air from the suction port 2211b with an aspirator (not shown), the object O can be sucked to the palm 2211 and the object O can be made to follow the posture of the palm 2211. Therefore, in this case, the object O can be made to follow the posture of the palm 2211 more reliably, and it is not necessary to move the posture of the hand unit 20 just to drop the object O onto the palm 2211 by gravity.

  Further, for example, instead of pressing the object Ox gripped by one hand unit 20a against the object Oy gripped by the other hand unit 20b, the postures of the objects Ox and Oy are imitated by the posture of the palm 2211. Alternatively, the objects Ox and Oy may be pressed against the work table S, the wall, the other hand unit 20, the body unit 30, or other objects so that the postures of the objects Ox and Oy are made to follow the posture of the palm 2211.

  Further, for example, when the object O is brought into contact with the palm 2211 by gravity, the object 22 is vibrated with the fingers 22a to 222d opened so that the object O does not fall between the fingers 222a to 222d. The object O may be reliably brought into contact with three or more points that are not on the same straight line of the palm 2211. Even when the object O is in contact with one or two points or a straight line of the palm 2211, as long as the object O is in contact with the palm 2211, the hand 22 is compared with the case where the object O is not in contact with the palm 2211. The posture of the object O held by the hand 22 with respect to the hand 22 is unlikely to change.

  In the embodiment, the first axis direction and the second axis direction are orthogonal to each other. However, the first axis direction and the second axis direction are not necessarily orthogonal to each other. For example, as shown in FIG. 6D, the object is sandwiched in the diagonal direction (first axis direction) of the square-shaped object O in the plan view, and then in the second axis direction inclined 45 degrees from the diagonal line of the object O as shown in FIG. You may make it hold | grip. In this case, the hand 22 may be rotated by 45 degrees between steps S104 to S106. 6D, the object O can be centered in the diagonal direction by sandwiching the object O in the diagonal direction. The posture of the object O can be stabilized by sandwiching the object O in the diagonal direction with the apex angle of the object O positioned between the two fingers 222a and 222d (finger 222b and 222c).

  As shown in FIG. 6E, in step S104, the object O may be sandwiched between the fingers 222a to 222d in a state where the two fingers 222a and 222d press the curved surface of the object O. In this case, the object O can be positioned so that the contour of the curved surface passes through the tips of the two fingers 222a and 222d. In the case of FIG. 6E, when the other two fingers 222b and 222c press the single plane O1, the object O can be positioned in a direction orthogonal to the single plane. Thus, for example, when the object O is gripped by sandwiching the pair of parallel surfaces O2a and O2b with the fingers 222a to 222d in step S106, the fingers 222a to 222d are accurately positioned based on the position of the hand 22 in step S104. Can be moved.

  In the above, the fingers 222a to 222d movable in the biaxial direction are illustrated, but it is sufficient that at least two fingers 222 and 222 are provided and movable in the single axial direction as shown in FIG. 6F. In this case, after the fingers 222 and 222 are moved in the first axis direction in steps S104 and S105 and before step S106 is performed, the fingers 222 and 222 are movable in the second axis direction. The hand 22 may be rotated.

  In addition, the control sequence described in the above-described embodiment is merely an example, and it is needless to say that the present invention can be applied to various control sequences according to the configuration of the object O and the configuration of the hand unit 20.

DESCRIPTION OF SYMBOLS 1 ... Robot system, 9 ... Robot, 10 ... Imaging part, 11 ... Camera, 20 ... Hand unit, 21 ... Arm, 22 ... Hand, 30 ... Body unit, 40 ... Control apparatus, 41 ... CPU, 42 ... Memory | storage part, 43 ... Input reception unit, 44 ... Communication unit, 221 ... Palm unit, 222 ... Finger, 2211 ... Palm, 2211b ... Suction port, 2214 ... Base, M1 ... Image acquisition unit, M2 ... Image recognition unit, M3 ... Hand unit control Part, O ... object

Claims (16)

A hand unit having a first finger, a second finger, and a third finger, and a control device;
The hand unit is based on a control signal output from the control device.
Based on the position of the first finger and the position of the second finger, the hand unit is brought into contact with an object by bringing the first finger and the second finger close to each other in the first axial direction. A first operation for centering the object with respect to
After the first action, perform a second action of separating the first finger and the second finger from the object by separating the first finger and the second finger in the first axial direction,
After the second operation, based on the centering position, the first finger and the third finger are moved closer to each other in a second axis direction perpendicular to the first axis direction, and the object Perform a third action to grip the object,
robot. The hand unit comprises a fourth finger;
The hand unit is based on a control signal output from the control device.
The third finger and the fourth finger are brought close to each other in the first axial direction to contact the object, and based on the position of the third finger and the position of the fourth finger, Performing a fourth operation of centering the object relative to a hand unit;
After the fourth action, perform a fifth action of separating the third finger and the fourth finger from the object by separating the third finger and the fourth finger in the first axis direction,
After the fifth operation, based on the centering position, a sixth operation is performed in which the second finger and the fourth finger are brought close to each other in the second axis direction to grip the object. ,
The robot according to claim 1. The hand unit is based on a control signal output from the control device.
After performing the second action and the fifth action, the first finger and the third finger are separated from each other in the second axis direction, and the second finger and the fourth finger are separated. And a seventh operation for separating the two in the second axis direction,
After the seventh movement, the first finger and the second finger are moved closer to each other in the first axial direction, and the third finger and the fourth finger are moved closer to each other in the first axial direction. Perform the eighth action
After the eighth operation, the third operation and the sixth operation are performed.
The robot according to claim 2. When viewed in plan from a third axis direction that is perpendicular to the first axis direction and the second axis direction,
The first finger includes a first side portion that is perpendicular to the first axial direction,
The second finger includes a second side that is perpendicular to the first axial direction,
The third finger includes a third side portion that is perpendicular to the first axial direction,
The fourth finger includes a fourth side perpendicular to the first axis direction,
In the first operation and the fourth operation, the first side, the second side, the third side, and the fourth side are in contact with the object.
The robot according to claim 2 or 3. When viewed in plan from the third axis direction,
The first finger includes a fifth side perpendicular to the second axial direction;
The second finger includes a sixth side perpendicular to the second axial direction,
The third finger includes a seventh side perpendicular to the second axial direction;
The fourth finger includes an eighth side perpendicular to the second axial direction;
In the third operation and the sixth operation, the fifth side, the sixth side, the seventh side, and the eighth side are in contact with the object.
The robot according to claim 4. When viewed in plan from the third axis direction,
The first side is perpendicular to the fifth side;
The second side is perpendicular to the sixth side;
The third side is perpendicular to the seventh side;
The fourth side is perpendicular to the eighth side;
The robot according to claim 5. In the first operation and the fourth operation, the position of the first side and the position of the third side coincide with each other in the first axis direction,
The position of the second side and the position of the fourth side coincide with each other in the first axis direction;
The robot according to any one of claims 4 to 6. In the third operation and the sixth operation, the position of the fifth side and the position of the sixth side coincide with each other in the second axis direction,
The position of the seventh side and the position of the eighth side coincide with each other in the second axial direction.
The robot according to claim 5 or 6. The hand unit includes a palm having a surface perpendicular to the third axis direction and moving in the third axis direction.
The robot according to any one of claims 4 to 8. An arm having the hand unit;
The arm is based on a control signal output from the control device.
Moving the hand unit to a position where the palm and the object overlap when viewed in plan from the third axis direction;
The robot according to claim 9. An imaging device for imaging an object;
The control device identifies a position of the object based on an image captured by the imaging device;
The robot according to any one of claims 1 to 10. The arm is based on a control signal output from the control device.
Performing a ninth movement until the palm touches the object;
After the ninth operation, a tenth operation is performed in which the palm is moved away from the object by moving in the third axis direction.
The robot according to claim 10. A hand unit having a first finger, a second finger, and a third finger, and a control device;
The hand unit is based on a control signal output from the control device.
Based on the position of the first finger and the position of the second finger, the hand unit is brought into contact with an object by bringing the first finger and the second finger close to each other in the first axial direction. A first operation for centering the object with respect to
After the first action, perform a second action of separating the first finger and the second finger from the object by separating the first finger and the second finger in the first axial direction,
After the second operation, based on the centering position, the first finger and the third finger are moved closer to each other in a second axis direction perpendicular to the first axis direction, and the object Perform a third action to grip the object,
Robot system. The hand unit comprises a fourth finger;
The hand unit is based on a control signal output from the control device.
The third finger and the fourth finger are brought close to each other in the first axial direction to contact the object, and based on the position of the third finger and the position of the fourth finger, Performing a fourth operation of centering the object relative to a hand unit;
After the fourth action, perform a fifth action of separating the third finger and the fourth finger from the object by separating the third finger and the fourth finger in the first axis direction,
After the fifth operation, based on the centering position, a sixth operation is performed in which the second finger and the fourth finger are brought close to each other in the second axis direction to grip the object. ,
The robot system according to claim 13. A control device for controlling a robot including a hand unit having a first finger, a second finger, and a third finger,
Based on the position of the first finger and the position of the second finger, the hand unit is made to approach the first finger and the second finger in the first axial direction to contact an object. A first operation for centering the object with respect to the hand unit,
After the first operation, the hand unit is caused to perform a second operation for separating the first finger and the second finger from the object by separating the first finger and the second finger in the first axial direction,
After the second operation, based on the centering position, the first finger and the third finger are moved closer to each other in a second axis direction perpendicular to the first axis direction, and the object Causing the hand unit to perform a third action of gripping an object,
Control device. A control device for controlling a robot including a hand unit having a fourth finger,
Based on the position of the third finger and the position of the fourth finger, the third finger and the fourth finger are brought close to each other in the first axis direction and brought into contact with the object. Causing the hand unit to perform a fourth action of centering the object with respect to the hand unit;
After the fourth operation, the hand unit is caused to perform a fifth operation for separating the third finger and the fourth finger from the object by separating the third finger and the fourth finger in the first axial direction,
After the fifth operation, based on the position of the centering, a sixth operation that causes the second finger and the fourth finger to approach each other in the second axis direction to grip the object. Let the hand unit do it,
The control device according to claim 15.

Images