JP5895346B2 - Robot, robot control apparatus, robot control method, and robot control program - Google Patents

Description

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

  In recent years, SCARA robots, multi-axis robots, and the like are used for assembly and inspection of products at manufacturing sites and the like. When an object is transported when a product is assembled or inspected, the robot sucks the object or holds it by an arm.

  In such an industrial robot, it is required to efficiently grasp an object having various and various postures in a predetermined posture in automatic assembly and other work processes. In such an industrial robot, a driver is attached to the end effector of the robot, and the industrial robot automatically performs screw tightening on behalf of the human.

  The screw tightening machine described in Patent Document 1 is installed on a driver base in which a plurality of driver units are moved up and down, and is further arranged on a guide base in which a plurality of driver bits of the plurality of driver units are moved up and down integrally with the driver base. ing. And invention of patent document 1 vibrates the screw fastening tool extended from a driver unit by vibrating this guide stand in a horizontal direction. According to the vibration of the guide stand, the invention described in Patent Document 1 is configured such that the screw head and the driver bit are engaged.

  The invention described in Patent Document 2 supplies screws from a screw supply mechanism to a screw tightening mechanism. The control unit of the screw tightening mechanism controls the torque applied to the screw tightening function, and performs the final tightening after temporarily tightening the screw. And the invention of patent document 2 respond | corresponded to various screws by providing the screw fastening mechanism controlled in this way in the end effector of a robot.

JP-A-8-71867 Japanese Unexamined Patent Publication No. 64-11740

  However, in the invention described in Patent Document 1, a plurality of driver units are installed in advance on the driver base in accordance with an object to be screwed, and a plurality of driver bits are installed in advance on the guide base in accordance with an object to be screwed. It was. For this reason, it is necessary to introduce the screw tightening machine of patent document 1 according to the object which tightens a screw, and lacks versatility. In addition, since the driver base and the guide base are made exclusively for the screw and the target to be tightened, a general-purpose driver cannot be used.

  Further, in the invention described in Patent Document 2, since the screw tightening mechanism includes a screw supply mechanism and the screw tightening mechanism is also dedicated, it lacks versatility. In addition, when the screw tightening mechanism is attached to the end effector, it is necessary to change the work because it cannot cope with other work unless the end effector is replaced. Work becomes necessary.

  The present invention has been made in view of the above problems, and provides a robot, a robot control device, a robot control method, and a robot control program that prevent the occurrence of poor tightening even when a general-purpose driver is used. It is an object.

In order to achieve the above object, the robot of the present invention grips a screwdriver, which is fitted in the groove of the head of the screw, with the engagement portion of the tip portion of the driver bit magnetized by the arm portion, and A negative acceleration in which the tip is brought into contact and the driver is accelerated and moved at a first acceleration, which is a positive acceleration that accelerates in the moving direction of the driver unit, and the driver is accelerated in the moving direction of the driver unit. The second acceleration is decelerated and stopped, and the groove and the tip are fitted.
In order to achieve the above object, a robot control device according to the present invention is a robot control device for controlling a robot, wherein an engagement portion at a tip portion of a driver bit that is fitted in a groove in a screw head is magnetized. The driver is gripped by the arm of the robot, and the tip is brought into contact with the groove, and the driver is accelerated and moved at a first acceleration that is a positive acceleration that accelerates in the moving direction of the driver unit. The driver is decelerated and stopped at a second acceleration, which is a negative acceleration that accelerates in the moving direction of the driver unit, and the groove and the tip are fitted.
In order to achieve the above object, the robot control method according to the present invention is configured so that the robot is engaged with a screwdriver in which the engaging portion of the tip of the driver bit that is fitted in the groove of the screw head is magnetized. A step of gripping;
The robot is moved by accelerating the driver at a first acceleration that is a positive acceleration that accelerates in the moving direction of the driver unit by bringing the tip into contact with the groove and moving the driver to the driver unit. A step of decelerating and moving at a second acceleration, which is a negative acceleration that accelerates in the moving direction, and a step of fitting the groove and the tip portion into the robot.
In order to achieve the above object, the robot control program of the present invention is a program for causing a computer to execute a process of controlling an arm portion that grips a driver whose engagement portion at the tip of a driver bit is magnetized. , A procedure of fitting a screwdriver in which the engaging portion of the tip portion of the driver bit is magnetized by the arm portion to be fitted into the groove at the head of the screw, and the screwdriver by bringing the tip portion into contact with the groove, Accelerate and move with a first acceleration, which is a positive acceleration that accelerates in the direction of movement of the driver unit, and decelerate the driver with a second acceleration, which is a negative acceleration that accelerates in the direction of movement of the driver unit. A procedure of stopping and a procedure of fitting the groove and the tip end portion are executed.
In order to achieve the above object, a robot according to the present invention includes an arm portion that holds a driver in which an engagement portion at a tip of a driver bit is magnetized, and a control portion that controls the arm portion, and the control portion. In the state where the engaging portion magnetized by the driver is pressed against the groove on the top surface of the head of the screw having a head that can be engaged by magnetic force, the arm portion is moved at a first predetermined acceleration. Move.

  According to the present invention, the arm portion is placed in a state where the screwdriver whose magnetized engaging portion at the tip of the driver bit is pressed against the groove on the top surface of the screw head having a head that can be engaged by magnetic force. It is moved at a predetermined acceleration of 1. For this reason, even if the magnetized engaging portion of the driver is not properly fitted by pressing against the groove on the top surface of the screw head, the screw is moved at the first predetermined acceleration, so that the screw is engaged with the driver. The shape of the joint portion and the shape of the groove on the top surface of the screw head are guided to a fitting position, and the fitting is performed correctly. For this reason, even if it uses a general purpose driver, the engaging part of a driver and the groove | channel of the screw head top surface can be correctly fitted.

  In order to achieve the above object, in the robot according to the present invention, the control unit accelerates and moves the arm unit with a first acceleration, and decelerates and stops the arm unit with a second acceleration. Also good.

  According to the present invention, the arm portion is moved at the first predetermined acceleration, and the arm portion is moved at the second predetermined acceleration. For this reason, even if it is moved at the first acceleration, even if the engagement portion of the driver and the groove on the top surface of the screw are not fitted, the screw is moved by the second acceleration, so that the screw The shape of the engaging portion and the shape of the groove on the top surface of the screw head are guided to a position where the engaging portion is fitted, and the fitting is performed correctly. For this reason, even if it uses a general purpose driver, the engaging part of a driver and the groove | channel of the screw head top surface can be correctly fitted.

To achieve the above object, in a robot of the present invention, the first acceleration is a positive acceleration with respect to the moving direction of de Rye bar unit, the second acceleration, negative acceleration with respect to the moving direction of the driver unit You may make it.

  According to the present invention, the first acceleration is a positive acceleration with respect to the moving direction of the driver, and the second acceleration is a negative acceleration with respect to the moving direction of the driver. Even if it does not fit correctly by pressing into the groove on the top surface of the head of the screw, the screw is driven by the positive acceleration or the negative acceleration to cause the screw to engage with the screw The shape of the groove is guided to the position where it fits and fits correctly. For this reason, even if it uses a general purpose driver, the engaging part of a driver and the groove | channel of the screw head top surface can be correctly fitted.

  In order to achieve the above object, in the robot of the present invention, the control unit tilts the driver to which the screw is attracted to a predetermined angle, images the driver to which the screw is adsorbed, and displays the captured image. And determining the fitting state between the engagement portion of the driver and the groove on the top surface of the screw, and the determination result is the groove on the top surface of the screw and the engagement portion of the screwdriver. When the screw is correctly fitted, the screw that is attracted to the screw may be moved toward the screw groove of the object to be screwed to perform screw tightening.

  According to the present invention, the screw driver is tilted at a predetermined angle to pick up an image of the screw screw driver, and the driver engagement portion and the screw head top groove using the picked image. The state of fitting with is determined. As a result of the determination, when the driver engaging part and the groove on the top surface of the screw are fitted, the screw is tightened. The groove on the top surface of the screw head can be correctly fitted.

  In order to achieve the above object, in the robot of the present invention, the predetermined angle may be an angle of a thread groove of an object to which the screw is attached.

  According to the present invention, the state of fitting between the engagement portion of the driver and the groove on the top surface of the screw head is determined by tilting to an angle based on the angle of the screw groove of the object to which the screw is attached. The fitting state can be determined by the angle at which the actual screw tightening is performed. For this reason, even if a general-purpose driver is used, it can be determined whether or not the engagement portion of the driver and the groove on the top surface of the screw are correctly fitted. Further, after the determination, the screw can be tightened as it is.

  In order to achieve the above object, the robot of the present invention includes an imaging device, and the control unit is similar to an image obtained when the arm unit imaged by the imaging device is tilted at a predetermined angle and template image data. Based on the degree, the engagement state of the engagement portion of the driver and the groove on the top surface of the head of the screw may be determined.

  According to the present invention, on the basis of the similarity between the image when the arm portion imaged by the imaging device is tilted at a predetermined angle and the template image data, the magnetized engaging portion of the driver and the top of the screw head Since the state of engagement with the groove on the surface is determined, the state of engagement between the engagement portion magnetized by the driver and the groove on the top surface of the screw head can be clearly determined. For this reason, even if it uses a general purpose driver, the engaging part of a driver and the groove | channel of the screw head top surface can be correctly fitted.

To achieve the above object, in a robot of the present invention, the control unit, while rotating the arm portion that grips the drivers Jo Tokoro speed, the engagement portion of the tip of the screwdriver bit You may make it press on the groove | channel on the head top surface of the said screw.

  According to the present invention, the engagement portion at the tip of the driver bit is pressed against the groove on the top surface of the screw head while the arm portion holding the driver is rotated at a predetermined speed. And the groove on the top surface of the screw head can be fitted. Further, even if the engagement portion of the driver and the groove on the top surface of the screw are not properly fitted in this process, the driver is moved at the first predetermined acceleration or the driver is moved to the second position. By moving at a predetermined acceleration, the engagement portion of the driver and the groove on the top surface of the screw head can be correctly fitted.

  In order to achieve the above object, in the robot of the present invention, the driver may be an electric driver.

  According to the present invention, since the electric screwdriver is used, it is possible to correctly fit the engagement portion of the driver and the groove on the top surface of the screw head using a general-purpose screwdriver.

  In order to achieve the above object, a robot control apparatus of the present invention includes an arm portion that holds a driver whose engagement portion at the tip of a driver bit is magnetized, and a control portion that controls the arm portion, The controller is configured to press the engaging portion of the screwdriver against the engaging portion of the screw in a state where the engaging portion of the screwdriver is pressed against a groove on the top surface of the screw having a head that can be engaged by a magnetic force. Inertia that is smaller than the attractive force generated by the magnetic force when the groove of the surface is fitted and larger than the attractive force generated by the magnetic force when the groove on the top surface of the screw head is in contact with the engaging portion of the screwdriver The driver, to which the screw is attracted, is moved at a first predetermined acceleration at which a force acts on the screw.

  In order to achieve the above object, according to the robot control method of the present invention, a control unit that controls an arm unit that grips a driver in which an engagement unit at a tip of a driver bit is magnetized, the engagement unit of the driver is A step of pressing against a groove on the top surface of a screw having a head that can be engaged by a magnetic force, and an adsorption caused by a magnetic force in a state in which the groove on the top surface of the screw is engaged with the engaging portion of the driver; A first predetermined acceleration at which an inertial force that is smaller than a force and that is greater than an attraction force generated by a magnetic force in a state where the groove on the top surface of the screw is in contact with the engagement portion of the driver acts on the screw. And a step of moving the screwdriver on which the screw is adsorbed.

  In order to achieve the above object, the robot control program according to the present invention includes: a control unit that controls an arm unit that grips a driver in which an engagement part at a tip of a driver bit is magnetized; The step of pressing the joint portion against the groove on the top surface of the screw head having a head that can be engaged by magnetic force, and the groove on the top surface of the screw in the engagement portion of the screwdriver A first inertial force acting on the screw is smaller than the attracting force generated by the magnetic force and larger than the attracting force generated by the magnetic force in a state where the groove on the top surface of the screw head is in contact with the engaging portion of the driver. And a step of moving the driver to which the screw is attracted at a predetermined acceleration.

  According to the present invention, the arm portion is placed in a state where the screwdriver whose magnetized engaging portion at the tip of the driver bit is pressed against the groove on the top surface of the screw head having a head that can be engaged by magnetic force. It is moved at a predetermined acceleration of 1. For this reason, even if the magnetized engaging portion of the driver is not properly fitted by pressing against the groove on the top surface of the screw head, the screw is moved at the first predetermined acceleration, so that the screw is engaged with the driver. The shape of the joint portion and the shape of the groove on the top surface of the screw head are guided to a fitting position, and the fitting is performed correctly. Therefore, it is possible to provide a robot control device, a robot control method, and a robot control program that can correctly fit the engagement portion of the driver and the groove on the top surface of the screw even if a general-purpose driver is used.

1 is a perspective view showing a schematic configuration of a robot 1 according to a first embodiment. It is a conceptual diagram of the arm part 20 and the force sensor 30 which concern on the embodiment. 3 is a block diagram of a control unit 100 according to the embodiment. FIG. It is a flowchart of operation | movement until it attaches the screw | thread 211 to the front-end | tip of the driver unit 50 which concerns on the embodiment, and performs screwing. It is a figure explaining the operation | movement which fits the screw | thread 211 to the front-end | tip of the driver unit 50 which concerns on the embodiment. It is a figure explaining the operation | movement which pulls out the screw 211 which concerns on the embodiment from the rail 201 of the taking-out part of an automatic screw feeder. It is a figure explaining the operation | movement which moves to the object part 301 which performs screw fastening in the same direction as the direction which pulled out the screw | thread 211 which concerns on the embodiment. It is a figure explaining the operation | movement which moves to the object part 301 which performs screw fastening in the reverse direction to the direction which pulled out the screw | thread 211 which concerns on the embodiment. It is a figure explaining whether the screw | thread 211 is fitted to the engaging part 52 of the driver unit 50 which concerns on the embodiment. It is a figure explaining the bolting operation of screw 211 concerning the embodiment. It is a figure explaining an example of the moving speed of the driver unit according to the embodiment. It is a figure explaining an example in which the screw | thread 211 is correctly fitted by the engaging part 52 of the driver unit 50 which concerns on the embodiment. It is a figure explaining an example in which the screw | thread 211 is not correctly fitted by the engaging part 52 of the driver unit 50 which concerns on the embodiment. It is a flowchart of operation | movement until a screw | thread 211 is attached to the front-end | tip of the driver unit 50 which concerns on 2nd Embodiment, and screwing is performed. It is a figure explaining the fastening operation | movement of the screw | thread 211 when the screw fastening target object 301 which concerns on the embodiment inclines. It is a flowchart of operation | movement until attaching the screw 211 to the front-end | tip of the driver unit 50 which concerns on 3rd Embodiment, and performing screw fastening. It is a perspective view which shows schematic structure of the robot 1a which concerns on 4th Embodiment. It is a flowchart of operation | movement of the robot 1a which concerns on the same embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to such embodiment, A various change is possible within the range of the technical thought. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

[First Embodiment]
FIG. 1 is a perspective view showing a schematic configuration of a robot 1 according to the present embodiment. As shown in FIG. 1, the robot 1 includes one arm 2. The arm 2 includes a fixed portion 10, an arm portion 20, a force sensor 30, and an end effector 40. The robot 1 operates under the control of the control unit 100. An imaging device 60 is connected to the control unit 100.

Here, the screw 211 will be described as an example of the object. The head shape of the screw is, for example, a pan, a dish, a round dish, a truss, a binding, a low head, or the like. The shape of the thread groove or non-penetrating groove is, for example, sitting (minus), cross hole (plus), S shape, plus / minus, hexagonal hole, square hole.
Moreover, the screw 211 is previously arrange | positioned on the rail 201 of the taking-out part of a screw automatic feeder. In addition, the screw automatic supply machine arrange | positions the screw | thread 211 on the rail 201 of an extraction part by a well-known technique (for example, refer WO2003 / 106307). Alternatively, a magazine in which the screws 211 are previously arranged on the rails may be used.

The fixing unit 10 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage. The fixing unit 10 includes a control unit 100 (illustrated by a broken line) inside.
The control unit 100 controls the arm unit 20, the end effector 40, and the driver unit 50 attached to the end effector. Details of the control unit 100 will be described later. The control unit 100 may be provided outside the fixed unit 10 instead of inside the fixed unit 10.

  The arm unit 20 includes a first frame 21, a second frame 22, a third frame 23, a fourth frame 24 and a fifth frame 25. The first frame 21 is rotatably or refractably connected to the fixed portion 10 via a rotational refraction axis. The second frame 22 is connected to the first frame 21 and the third frame 23 via a rotational refraction axis. The third frame 23 is connected to the second frame 22 and the fourth frame 24 via a rotational refraction axis. The fourth frame 24 is connected to the third frame 23 and the fifth frame 25 via a rotational refraction axis. The fifth frame 25 is connected to the fourth frame 24 via a rotational refraction axis. Under the control of the control unit 100, the arm unit 20 moves as the frames 21 to 25 are rotated or refracted around each rotational refraction axis.

  An end effector 40 is provided on the other side of the fifth frame 25 of the arm unit 20 where the fourth frame 24 is provided. The end effector 40 grips the driver unit 50 directly. The end effector 40 has a structure that has a plurality of frames and can hold the driver unit 50, for example.

  A force sensor 30 is interposed between the fifth frame 25 of the arm unit 20 and the end effector 40. The force sensor 30 detects each spatial component of force applied to the end effector 40 of the arm 2 (referred to as a force component) and each spatial component of torque (referred to as a torque component). The force sensor 30 outputs information including the detected force component and torque component applied to the end effector 40 of the arm 2 to the control unit 100.

  The driver unit 50 (also referred to as a driver) is an electric driver. The driver unit 50 includes a driver bit 51, and an engaging portion 52 of the driver bit 51 (hereinafter referred to as an engaging portion 52 of the driver unit 50) is magnetized.

  Similar to the robot 1, the imaging device 60 is installed horizontally with respect to the floor. The imaging device 60 is, for example, a CCD (Charge Coupled Device) camera. The imaging device 60 images the screw 211 adsorbed by the engaging portion 52 of the driver unit 50 and outputs the captured analog value image data to the control device 100.

The control unit 100 controls the arm unit 2 0 and the end effector 40 of the robot 1 as described later. Further, the control unit 100 determines whether or not the screw 211 attracted to the engagement unit 52 of the driver unit 50 is correctly fitted based on the image data output from the imaging device 60, as will be described later. Based on the determination result, the controller 100 tightens the screw 211 into the screw hole of the object to be screwed when the screw 211 attracted to the engaging portion 52 of the driver unit 50 is correctly fitted. The driver unit 50 is controlled.

FIG. 2 is a conceptual diagram of the arm unit 20 and the force sensor 30 according to the present embodiment.
As shown in FIG. 2, the arm portion 20 of the arm 2 includes rotating portions 82, 83, and 85 and refracting portions 81, 84, and 86. The arm unit 20 of the arm 2 includes a force sensor 30 between the end effector 40 and the arm unit 20.

  The refracting portion 81 is provided between the fixed portion 10 and the first frame 21. The rotating part 82 is provided between the first frame 21 and the second frame 22. The rotating unit 83 is provided between the second frame 22 and the third frame 23. The refracting portion 84 is provided between the third frame 23 and the fourth frame 24. The rotating unit 85 is provided between the fourth frame 24 and the fifth frame 25. The refracting portion 86 is provided on the other side of the fifth frame 25 where the fourth frame 24 is provided.

  As shown in FIG. 2, the arm part 20 is a 6-axis arm having 6 degrees of freedom. That is, the end effector 40 at the distal end of the arm portion 20 moves by the operation of the rotating portion and the refracting portion of each axis. When the end effector 40 is gripping the driver unit 50, the external force detected by the force sensor 30 includes such components due to the operations of the rotating portion and the refracting portion of each axis. For this reason, since the arm part 20 is a 6-axis arm, it can be controlled by six variables. For example, three variables (components) of the position (x, y, z), an angle (α , Β, γ) can be controlled corresponding to the three components (variables).

FIG. 3 is a block diagram of the control unit 100 according to the present embodiment.
As illustrated in FIG. 3, the control unit 100 includes an image acquisition unit 101, a screw posture determination unit 102, a sensor output acquisition unit 103, an arm control unit 104, a drive unit 105, and a storage unit 106.

  The image acquisition unit 101 acquires image data output from the imaging device 60 and converts the acquired image data into digital data. The image acquisition unit 101 outputs the converted image data to the screw posture determination unit 102. When the image data output from the imaging device 60 is a digital value, the image acquisition unit 101 outputs the acquired image data as it is to the screw posture determination unit 102 without conversion.

  The screw posture determination unit 102 reads image data for performing template matching stored in the storage unit 106. The screw posture determination unit 102 performs known template matching using the image data output from the image acquisition unit 101 and the image data for performing template matching read from the storage unit 106. The screw posture determination unit 102 determines whether or not the screw 211 is attached to the tip 52 of the driver unit 50 in a correct posture by template matching. The screw posture determination unit 102 outputs the determination result to the arm control unit 104. Note that the screw 211 is attached to the front end 52 of the driver unit 50 in the correct posture, as will be described later, the engaging portion 52 of the driver unit 50 and the screw 211 are engaged (fitted). ) State.

  The sensor output acquisition unit 103 acquires information including a force component and a torque component applied to the end effector 40 of the arm 2 output from the force sensor 30, and extracts the force component and the torque component from the acquired information. The sensor output acquisition unit 103 outputs information indicating the extracted force component and torque component to the arm control unit 104.

  The arm control unit 104 receives the determination result output from the screw posture determination unit 102 and the information indicating the force component and the torque component output from the sensor output acquisition unit 103. The arm control unit 104 reads control information stored in advance in the storage unit 106. The arm control unit 104 is described later based on the control information read from the storage unit 106, the determination result output by the screw posture determination unit 102, and the information indicating the force component and the torque component output by the sensor output acquisition unit 103. Thus, a drive signal for controlling the arm unit 20 is generated. The arm control unit 104 outputs the generated drive signal to the drive unit 105.

  The drive unit 105 drives the arm unit 20 of the robot 1 according to the drive signal output from the arm control unit 104.

  The storage unit 106 stores image data for performing template matching and control information of the robot 1 in advance. The image data for performing template matching stored in the storage unit 106 may be stored in advance for each length or weight of the screw 211, for example. As will be described later, the image data for performing template matching stored in the storage unit 106 is correctly fitted between the engagement unit 52 of the driver unit 50 and the screw 211 when the driver unit 50 is tilted at a predetermined angle. This is image data in a state of being in operation. Alternatively, the image data for performing template matching stored in the storage unit 106 is the groove on the top surface of the head portion of the screw 211 and the engaging portion 52 of the driver unit 50 when the driver unit 50 is tilted at a predetermined angle. Or it is image data in a state where the holes are not properly fitted.

Next, operations from attaching the screw 211 to the engaging portion 52 of the driver unit 50 and tightening the screw will be described with reference to FIGS.
FIG. 4 is a flowchart of an operation until the screw 211 is attached to the tip of the driver unit 50 according to the present embodiment and screw tightening is performed.
FIG. 5 is a diagram for explaining the operation of fitting the screw 211 to the tip of the driver unit 50 according to the present embodiment. 5 (a) is a diagram driver unit illustrating a case in an initial state of the height h ₀ of the y-axis. FIG. 5B is a diagram illustrating a case where the driver unit is at the height h ₁ of the y-axis. 5 (c) is a diagram driver unit will be described when in the height h ₂ of the y-axis.

FIG. 6 is a diagram illustrating an operation of pulling out the screw 211 according to the present embodiment from the rail 201 of the take-out unit of the automatic screw feeder. FIG. 7 is a diagram illustrating an operation of moving the screw 211 according to the present embodiment to the target portion 301 to be screwed in the same direction as the direction in which the screw 211 is pulled out. Further, in FIG. 7, the end effector 40, the driver unit 50, the engaging portion 52 of the driver unit 50, and the screw 211 indicated by the one-dot broken line are engaged with the driver unit 50 at the positions −x ₂ and −x _3. The fitting state of the part 52 and the screw 211 is shown. Further, the position -x ₂ is more negative than the position -x ₁ , and the position -x ₃ is more negative than the position -x ₂ .
FIG. 8 is a diagram illustrating an operation of moving the screw 211 according to the present embodiment to the target portion 301 to be screwed in the direction opposite to the direction in which the screw 211 is pulled out. Further, in FIG. 8, the end effector 40, the driver unit 50, the engaging portion 52 of the driver unit 50, and the screw 211 indicated by the one-dot broken line are associated with the driver unit 50 at the respective positions x ₁₁ , x ₁₂ , and x _13. The fitting state of the joint part 52 and the screw 211 is shown. The position _{x 11} is a positive direction from the position -x _1, position _{x 12} is a positive direction from the position _{x 11,} the position _{x 13} is a positive direction from the position _{x 12.}

(Step S101)
The arm control unit 104 of the control unit 100 reads screw tightening control information stored in advance in the storage unit 106. The arm control unit 104 generates a drive signal for the driver unit 50 based on the read screw tightening control information, and outputs the generated drive signal to the drive unit 105. The drive unit 105 lowers the driver unit 50 from the height h ₀ to h ₁ as shown in FIGS. 5A to 5B based on the drive signal output from the arm control unit 104. That is, the control unit 100 moves the engagement unit 52 of the driver unit 50 in the negative y-axis direction toward the rail 201 of the take-out unit of the automatic screw feeder.
Hereinafter, based on the screw tightening control information read from the storage unit 106, the arm control unit 104 generates a drive signal for the driver unit 50, outputs the generated drive signal to the drive unit 105, and the drive unit 105 uses the drive signal as a drive signal. Based on this description, it is assumed that the control unit 100 controls a series of operations for driving the driver unit 50. After step S101 ends, the process proceeds to step S102.

(Step S102)
Next, as shown in FIG. 5 (c), the control unit 100 rotates the arm unit 20 at a predetermined number of rotations while moving the engagement unit 52 of the driver unit 50 onto the rail 201 of the take-out unit of the automatic screw feeder. It controls so that it may press on the front-end | tip of the screw | thread 211 arrange | positioned in (3). In this case, when the engaging unit 52 is pressed against the tip of the screw 211, the control unit 100 presses the driver bit 51 of the driver unit 50 with a torque that does not rotate. The torque that does not rotate the driver bit 51 is calculated in advance by experiment or based on the specifications of the driver unit 50. Alternatively, control section 100 lowers the driver unit 50 without rotating, when pressed against the engaging portion 52 at the tip of the screw 211, so as to impose a torque for rotating the driver bit 51 of the driver unit 50 Also good. The torque for rotating the driver bit 51 is calculated in advance by experiment or based on the specification of the driver unit 50.
The reason why the arm portion 20 is lowered so as to press against the tip of the screw 211 while rotating is that the shape of the convex portion at the tip of the driver unit 50 and the shape of the concave portion of the screw are fitted so that the attachment is performed correctly. It is to make it.
In this case, the sensor output acquisition unit 103 of the control unit 100 acquires information about the force output by the force sensor 40 and outputs the acquired information about the force to the arm control unit 104. The arm control unit 104 generates a drive signal for driving the tip convex portion of the driver unit 50 so as to press against the concave portion of the screw 211 based on the information regarding the force output from the sensor output acquisition unit 103.
As a result, the control unit 100 controls the force generated at the tip of the arm unit 20 and presses the tip of the driver unit 50 against the screw with a certain force or more. In this way, by rotating the tip of the driver unit 50, the shape of the convex portion at the tip of the driver unit 50 and the shape of the concave portion of the screw are fitted, and the attachment is performed correctly. After step S101 ends, the process proceeds to step S102.

(Step S103)
Next, the control unit 100 determines whether the drive signal is a signal for driving the pulling direction of the screw 211 from the rail 201 of the take-out unit of the automatic screw feeder and the moving direction to the target to which the screw 211 is attached in the same direction. Is determined.
When the direction in which the screw 211 is pulled out from the rail 201 of the take-out unit of the automatic screw feeder and the movement direction to the target to which the screw 211 is attached are the same driving signals (step S103; Yes), the process proceeds to step S104. When the direction in which the screw 211 is pulled out from the rail 201 of the take-out part of the automatic screw feeder and the movement direction to the target to which the screw 211 is attached are not the same driving signals (step S103; No), the process proceeds to step S107.

(Step S104)
Steps S104 to S106 will be described with reference to FIGS.
Next, as shown in FIG. 6, the control unit 100 controls the arm unit 20 to move the screw 211 from the position x ₀ to the position −x ₁ in the negative direction of the x-axis in the rail 201 of the take-out unit of the automatic screw feeder. Pull out from. By this operation, the screw 211 comes out of the rail 201 of the take-out part of the automatic screw feeder and becomes free.
Next, as illustrated in FIG. 7, at the position −x ₁ , the control unit 100 controls the arm unit 20 so that the driver unit 50 is driven at a predetermined acceleration in the negative x-axis direction in the same direction as the direction in which the screw is pulled out. To start the movement to the position in the negative x-axis direction where the screw tightening of the driver unit 50 is performed. After step S104 ends, the process proceeds to step S105.

Further, it is desirable that the engaging portion 52 of the driver unit 50 be vertically downward, and the screw 211 is guided to the engaging portion 52 of the driver unit 50 by gravity acting on the screw 211 in addition to the inertia force f1, and is correctly fitted. Match.
Further, since the driver unit 50 is accelerated, an inertial force f1 acts on the screw 211 in the direction opposite to the movement of the driver unit 50. At this time, a magnetic force attracting each other acts between the tip of the driver unit 50 and the screw 211, so that the friction between the driver unit 50 and the screw 211 is opposite to the direction in which the screw 211 tends to move. Force f2 works.
In step S102, when the screw 211 is correctly fitted in the engaging portion 52 of the driver unit 50, the shape of the convex portion of the engaging portion 52 of the driver unit 50 and the shape of the concave portion of the screw 211 are fitted. Is doing. For this reason, in addition to the frictional force f2 due to the magnetic force, the frictional force due to the engagement portion 52 of the driver unit 50 and the groove or hole on the top surface of the head of the screw 211 is added. growing. As a result, the inertial force f1 described above does not become larger than the frictional force f2, and the screw 211 does not move relative to the driver unit 50, so that the position does not change.

(Step S105)
Next, at the position −x ₂ , the control unit 100 controls the arm unit 20 to move the engagement unit 52 of the driver unit 50 in the negative x-axis direction at a constant speed, and tightens the driver unit 50 with screws. Move closer to the position to be performed.
The constant speed of the driver unit 50 is determined by the length, size, and weight of the screw 211, the shape of the groove or hole in the top surface of the screw 211, the groove or hole in the top surface of the screw 211, and the like. You may make it obtain | require by experiment beforehand according to the depth of a recessed part. The constant velocity is, for example, 0.8 [m / sec] when the screw 211 has a length of M3 of 10 [mm]. After step S105 ends, the process proceeds to step S106.

(Step S106)
Next, at the position −x ₃ , the control unit 100 controls the arm unit 20 to rapidly decelerate the engagement unit 52 of the driver unit 50, and at a position where the screwing of the driver unit 50 is performed at a predetermined position. The vehicle is suddenly decelerated with acceleration (second predetermined acceleration) and stopped.
Further, since the driver unit 50 is abruptly decelerated, at position -x _3, inertial force f3 in the same direction as the movement of the driver unit 50 acts against the screw 211.
In addition, since the magnetic force attracting each other works between the engaging portion 52 of the driver unit 50 and the screw 211, the direction between the driver unit 50 and the screw 211 is opposite to the direction in which the screw 211 tries to move. The frictional force f4 of works.
Therefore, the screw 211 moves relative to the driver unit 50 by rapidly decelerating the driver unit 50 so that the above-described inertia force f3 is larger than the frictional force f4.
Even if the screw 211 is not correctly attached to the engaging portion 52 of the driver unit 50 in step S102, the screw 211 is moved from the position x1 to the position x4 by the rapid deceleration. The shape of the convex portion of the engaging portion 52 and the shape of the groove on the top surface of the screw head or the concave portion of the hole are guided to a position where they are fitted, and the fitting is performed correctly.

Further, it is desirable that the engaging portion 52 of the driver unit 50 be vertically downward, and the screw 211 is guided to the lower end of the driver unit 50 by the gravity acting on the screw 211 in addition to the inertial force f3 and is properly fitted.
In step 102, when the screw 211 is correctly fitted in the engaging portion 52 of the driver unit 50, the shape of the convex portion of the engaging portion 52 of the driver unit 50 and the groove on the top surface of the head of the screw 211. Or the shape of the recessed part of a hole is fitting. For this reason, in addition to the frictional force f4 due to the magnetic force, the frictional force due to the engaging portion 52 of the driver unit 50 and the groove or hole on the top surface of the head of the screw 211 is applied. growing. As a result, the inertial force f3 described above does not become greater than the frictional force f4, and the screw 211 does not move relative to the driver unit 50, so that its position does not change (is not displaced).

The acceleration when the driver unit 50 is suddenly decelerated is a value at which the screw 211 does not move when the screw 211 is correctly attached to the driver unit 50 and decelerated, and the screw 211 moves when the screw 211 is not correctly attached. The designer of the robot 1 or the designer of the control information of the robot 1 is experimentally obtained in advance. Alternatively, the acceleration when the driver unit 50 is suddenly decelerated may be theoretically obtained from the magnetic force acting between the driver unit 50 and the screw 211, the friction coefficient between them, the mass of the screw 211, and the like. The acceleration in the case of rapid acceleration is, for example, 11 [m / sec ² ] when the length of the screw 211 is 10 [mm]. After step S106 ends, the process proceeds to step S110.

(Step S107)
Steps S107 to S109 will be described with reference to FIGS.
Next, as shown in FIG. 6, the control unit 100 controls the arm unit 20 to move the screw 211 from the position x ₀ to the position −x ₁ in the negative direction of the x-axis in the rail 201 of the take-out unit of the automatic screw feeder. Pull out from. By this operation, the screw 211 comes out of the rail 201 of the take-out part of the automatic screw feeder and becomes free.
Next, as illustrated in FIG. 8, at the position −x ₁ , the control unit 100 controls the arm unit 20 to raise the driver unit 50 from the height h ₂ to h ₃ . That is, the control unit 100 moves the engagement unit 52 of the driver unit 50 in the positive x-axis direction so that the screw 211 does not hit the rail 201 of the take-out unit of the automatic screw feeder.
After the ascent, at the position −x ₁ , the control unit 100 controls the arm unit 20 to rapidly accelerate the driver unit 50 at a predetermined acceleration in the positive x-axis direction opposite to the direction in which the screw is pulled out (first And the driver unit 50 is started to move to a position in the positive x-axis direction. 8, a diagram of the position x _11, due rapid acceleration diagrams after the posture of the screw 211 is changed. After step S107 ends, the process proceeds to step S108.

Further, since the driver unit 50 is accelerated rapidly, an inertial force f5 acts on the screw 211 in the direction opposite to the movement of the driver unit 50. At this time, a magnetic force attracting each other acts between the tip of the driver unit 50 and the screw 211, so that the screw 211 is moved in a direction opposite to the direction in which the screw 211 tries to move. The frictional force f6 of works.
Accordingly, the control unit 100 causes the screw 211 to move relative to the driver unit 50 by rapidly accelerating the driver unit 50 so that the above-described inertial force f5 is greater than the frictional force f6.

Note that the acceleration when the driver unit 50 is suddenly accelerated is that the screw 211 does not move when the screw 211 is correctly fitted to the driver unit 50, and the screw 211 is not properly fitted. The value at which 211 moves is experimentally determined by the designer of the robot 1 or the designer of the control information of the robot 1. Alternatively, it may be theoretically obtained from the magnetic force acting between the driver unit 50 and the screw 211, the coefficient of friction between them, the mass of the screw, and the like. The acceleration in the case of rapid acceleration is, for example, 11 [m / sec ² ] when the length of the screw 211 is 10 [mm].

  In step S102, when the screw 211 is correctly fitted into the engaging portion 52 of the driver unit 50, the shape of the convex portion of the engaging portion 52 of the driver unit 50 and the shape of the concave portion of the screw 211 are fitted. Is doing. For this reason, in addition to the frictional force f6 due to the magnetic force, the frictional force due to the engaging portion 52 of the driver unit 50 and the groove or hole on the top surface of the head of the screw 211 is applied. growing. As a result, the inertial force f5 described above does not become larger than the frictional force f6, and the screw 211 does not move relative to the driver unit 50, so that the position thereof does not change.

(Step S108)
Then, at position x _12, the control unit 100 controls the arm 20, moves the engagement portion 52 of the driver unit 50 at a constant speed, the driver unit 50, closer to the position for screwing.
The constant speed of the driver unit 50 is determined by the length, size, and weight of the screw 211, the shape of the groove or hole in the top surface of the screw 211, the groove or hole in the top surface of the screw 211, and the like. You may make it obtain | require by experiment beforehand according to the depth of a recessed part. The constant velocity is, for example, 0.8 [m / sec] when the screw 211 has a length of M3 of 10 [mm]. After step S108 ends, the process proceeds to step S109.

(Step S109)
Then, at position x _13, the control unit 100 controls the arm unit 20, by decelerating the engagement portion 52 of the driver unit 50, driver unit 50, in position for screwing in a predetermined acceleration Decelerate (second predetermined acceleration) and stop.

At position _{x 13,} driver unit 50 is decelerated, the inertial force f7 acts in the same direction as the movement of the driver unit 50 with respect to the screw 211.
In addition, since the magnetic force attracting each other works between the engaging portion 52 of the driver unit 50 and the screw 211, the direction between the driver unit 50 and the screw 211 is opposite to the direction in which the screw 211 tries to move. The frictional force f8 works.
In step 102, when the screw 211 is correctly fitted to the engaging portion 52 of the driver unit 50, the shape of the convex portion of the engaging portion 52 of the driver unit 50 and the groove or hole of the top surface of the head of the screw 211. The shape of the recess is fitted. For this reason, in addition to the frictional force f8 due to the magnetic force, the frictional force due to the engaging portion 52 of the driver unit 50 and the groove or hole on the top surface of the screw 211 is added. growing. As a result, the inertial force f7 described above does not become larger than the frictional force f8, and the screw 211 does not move relative to the driver unit 50, so that its position does not change (is not displaced). After step S109 ends, the process proceeds to step S110.

(Step S110)
After the driver unit 50 stops at the position where the screw tightening is performed, the control unit 100 tilts the driver unit 50 at a predetermined angle θ on the xy plane as shown in FIGS. 9B and 9C. The predetermined angle θ is, for example, 30 degrees or 45 degrees, and when the screw 211 is not properly fitted in the engagement portion 52 of the driver unit 50, the screw unit 50 is tilted to tilt the screw. 11 is an angle at which the groove or hole on the top surface of the head is displaced from the engaging portion 52 of the driver unit 50.
FIG. 9 is a view for explaining whether or not the screw 211 is fitted in the engaging portion 52 of the driver unit 50 according to the present embodiment. FIG. 9A is a diagram illustrating a fitting state of the engaging portion 52 of the driver unit 50 and the screw 211 when the screw unit is stopped at the position where the screw tightening is performed. FIG. 9B is a diagram illustrating a state in which the screw 211 is fitted when the driver unit 50 is tilted at an angle θ. FIG. 9C is a diagram illustrating a state where the screw 211 is not fitted when the driver unit 50 is tilted at an angle θ.

The reason why the driver unit 50 is tilted not vertically downward will be described. When the screw 211 is correctly attached to the engaging portion 52 of the driver unit 50 by steps S102 to S105, the shape of the convex portion of the engaging portion 52 of the driver unit 50 and the screw 211 are inclined by tilting the driver unit 50. The groove on the top surface of the head or the shape of the concave portion of the hole is fitted to increase the frictional force f9. In this case, the frictional force f9 acting on the engaging portion 52 of the driver unit 50 and the groove or hole on the top surface of the screw 211 is a frictional force according to the magnetic force generated by the engaging portion 52 of the driver unit, and the driver unit 50. This is the resultant force of the engaging portion 52 and the frictional force acting on the groove or hole on the top surface of the head of the screw 211.
As a result, the gravity G acting on the screw 211 does not become larger than the frictional force f9, and the screw 211 does not move (is not displaced) with respect to the engaging portion 52 of the driver unit 50, as shown in FIG. The fitted position does not change. That is, when the driver unit 50 is tilted at an angle θ with respect to the y axis, the screw 211 is also tilted with respect to the y axis at an angle θ.

On the other hand, when the screw 211 is not correctly attached to the engaging portion 52 of the driver unit 50, only the frictional force f10 corresponding to the magnetic force acts between the engaging portion 52 of the driver unit 50 and the screw 211. As a result, the gravity G generated in the screw 211 becomes larger than the frictional force f10, the screw 211 moves (displaces) with respect to the driver unit 50, and the position where the screw 211 is fitted as shown in FIG. The angle changes from the inclination angle θ to an angle θ of the screw 211 ′, for example, 0 degrees.
As shown in FIG. 9B and FIG. 9C, whether or not the screw 211 is fitted is clearly separated in the image data by inclining at an angle θ with respect to the y-axis. For this reason, there is an effect that it is easy to set the threshold value of the screw posture determination performed in step S207. After step S110 ends, the process proceeds to step S111.

(Step S111)
The image acquisition unit 101 of the control unit 100 acquires image data output from the imaging device 60 and converts the acquired image data into digital data. The image acquisition unit 101 outputs the converted image data to the screw posture determination unit 102.
The screw posture determination unit 102 determines whether or not the screw 211 is attached to the engagement unit 52 of the driver unit 50 in a correct posture from the image data output from the image acquisition unit 101 by known template matching or the like. . When the screw 211 is attached in the correct posture (step S111; Yes), the process proceeds to step S112. If the screw 211 is not attached in the correct posture (step S111; No), the process proceeds to step S114.

For example, the image data obtained by correctly attaching the screw 211 to the engaging portion 52 of the driver unit 50 in advance is used as template image data, and the designer of the robot 1 or the control information designer of the robot 1 stores the image data in the storage unit 106 in advance. Let me. Then, the screw posture determination unit 102 calculates the similarity between the stored template image data and the image data output from the image acquisition unit 101 by the template matching method. The screw posture determination unit 102 determines whether or not the screw 211 is fitted to the engagement unit 52 of the driver unit 50 in a correct posture according to the magnitude of the calculated similarity value.
The screw posture determination unit 102 experimentally obtains a similarity in advance when the amount of deviation between the engagement portion 52 of the driver unit 50 and the screw 211 is a deviation that is allowable in screw tightening, and determines the value. Set as a threshold. Then, the screw posture determination unit 102 determines that the calculated similarity is good when it is equal to or higher than a preset threshold value, and is negative when it is less than that.

As described above, when the image of the screw 211 fitted to the engagement portion 52 of the driver unit 50 is taken by the imaging device 60, the similarity with the template is bipolarized by tilting the posture of the driver unit 50. The As a result, the screw posture determination unit 102 can clearly determine pass / fail.
In addition, the quality determination of fitting is not restricted to the above-mentioned method, For example, using the edge extraction method etc., the relationship between the engaging part 52 of the driver unit 50 and the screw 211 is represented geometrically, and it is used. The pass / fail judgment may be performed. Also in this case, when photographing the screw 211 fitted to the engaging portion 52 of the driver unit 50 with the imaging device 60, the geometric relationship between the two can be changed by tilting the posture of the driver unit 50. Therefore, it is possible to clearly determine pass / fail.

(Step S112)
Next, the control unit 100 returns the driver unit 50 to a state where there is no inclination with respect to the y-axis (FIG. 10A). After step S112 ends, the process proceeds to step S113.
FIG. 10 is a diagram illustrating the tightening operation of the screw 211 according to the present embodiment. FIG. 10A is a diagram for explaining the operation of returning the driver unit 50 to its original inclination after sudden deceleration.
FIG. 10B is a diagram for explaining an operation of pressing the screw 211 against the screw hole 311 of the object 301 to be screwed.

(Step S113)
Next, the control unit 100 moves the driver unit 50 gripped by the arm unit 20 in the negative y-axis direction and presses the screw 211 against the screw hole 311 of the object 301 to be screwed. By pressing, a torque for rotating the engaging portion 52 of the driver unit 50 is generated in the electric driver. For this reason, the control unit 100 performs screw tightening by pressing the screw 211 fitted to the engagement unit 52 of the driver unit 50 against the screw hole 311.

(Step S114)
When the screw 211 is not properly fitted to the engaging portion 52 of the driver unit 50 in step S111, the control unit 100 is attached to the object that generates a magnetic force larger than that of the engaging portion 52 of the driver unit 50. 211 is moved closer and the screw 211 is removed. After removing the screw 211, the process returns to step S101.
Further, the method of removing the screw 211 is not limited to the above-described method. For example, the inertial force acting on the screw 211 by suddenly accelerating or decelerating the tip of the arm unit 20 is between the screw 211 and the driver unit 50. The screw 211 may be removed by making it larger than the frictional force that works. Alternatively, the control unit 100 magnetizes the engaging portion 52 of the driver unit 50 during steps S102 to S109, and demagnetizes the engaging portion 52 of the driver unit 50 at step S110, thereby removing the screw 211. It may be.

FIG. 11 is a diagram for explaining an example of speed and acceleration during movement of the driver unit 50 according to the present embodiment. FIG. 11A is a diagram illustrating an example of the speed during movement of the driver unit 50. FIG. 11B is a diagram for explaining an example of acceleration while the driver unit 50 is moving. In FIG. 11A, the horizontal axis represents time, the vertical axis represents speed, and the reference g101 represents the change in speed with respect to time. In FIG. 11B, the horizontal axis represents time, the vertical axis represents acceleration, the symbol g102-1 represents acceleration at times t2 to t3, and the symbol g102-2 represents acceleration at times t4 to t5. .
As shown in FIGS. 11A and 11B, the speed of the driver unit 50 is 0 during the period from time t1 to time t2. This state is during the operation shown in FIGS. 5A to 5C, and the velocity in the x-axis direction is 0 (steps S101 to S102 in FIG. 4).
As shown in FIG. 11A, the speed of the driver unit 50 gradually increases from the speed 0 toward the speed V1 during the period from time t2 to time t3. (Step S104 in FIG. 4). And as shown in FIG.11 (b), during the period of time t2-t3, an acceleration is a positive acceleration like code | symbol g102-1.
As shown in FIGS. 11A and 11B, the speed of the driver unit 50 is constant at the speed V1 during the period from time t3 to time t4 (step S105 in FIG. 4).
As shown in FIG. 11A, during the period from time t4 to t5, the speed of the driver unit 50 decreases rapidly from the speed V1 toward the speed 0 (step S106 in FIG. 4). And as shown in FIG.11 (b), during the period of time t4-t5, an acceleration is a negative acceleration like the code | symbol g102-2.

FIG. 12 is a view for explaining an example in which the screw 211 is correctly fitted to the engaging portion 52 of the driver unit 50 according to the present embodiment. FIG. 13 is a diagram for explaining an example in which the screw 211 is not properly fitted to the engaging portion 52 of the driver unit 50 according to the present embodiment.
As shown in FIG. 12, when the engaging portion 52 of the driver unit 50 and the screw 211 are correctly fitted, when the driver unit 50 is tilted at an angle θ with respect to the y axis, the screw 211 is also moved with respect to the y axis. The angle θ is inclined.
On the other hand, as shown in FIG. 13, when the engaging portion 52 of the driver unit 50 and the screw 211 are not properly fitted, when the driver unit 50 is tilted at an angle θ with respect to the y-axis, the screw 211 is caused by gravity. Droops in the negative y-axis direction. For example, as shown in FIG. 13, the screw 211 is inclined by an angle −θ _{211 with} respect to the y-axis. In this case, the screw 211 is attached to the engaging portion 52 of the driver unit 50 by a magnetic force as shown in FIG. 13. Thus, the inclination angle of the screw 211 depends on where the engagement portion 52 of the driver unit 50 is in contact.
In this manner, whether the screw 211 is correctly fitted to the engaging portion 52 of the driver unit 50 can be clearly separated by tilting the driver unit 50. The angle for determining whether or not the screw 211 is correctly fitted to the engaging portion 52 of the driver unit 50 is set by actual measurement using the screw unit 211 and the screw unit 211 that are screwed in advance. It may be.

As described above, the control unit 100 presses the magnetized engaging portion 52 of the driver 50 against the hole on the top surface of the head of the screw 211. Thereafter, the control unit 100 causes the driver unit 50 to have an inertial force acting in a direction opposite to the movement of the driver unit 50 greater than a frictional force f2 acting between the driver unit 50 and the screw 211. Is accelerated and moved. For this reason, even if the engaging portion 52 of the driver 50 is not correctly fitted by being pressed into the hole on the top surface of the screw 211, the screw 211 has a shape of the convex portion at the tip of the driver unit 50 due to rapid acceleration. The shape of the concave portion of the screw is guided to the fitting position and the fitting is performed correctly. As a result, even if a general-purpose screwdriver is used, the engagement portion 52 of the driver 50 and the groove or hole on the top surface of the head of the screw 211 can be correctly fitted.
Further, even if the arm portion 20 is suddenly accelerated and moved, even if the engaging portion 52 of the driver 50 and the hole on the top surface of the screw 211 are not properly fitted, the arm portion 20 is suddenly decelerated. The screw 211 is guided to the position where the shape of the convex portion at the tip of the driver unit 50 and the shape of the concave portion of the screw are fitted, and is correctly fitted. As a result, even if a general-purpose screwdriver is used, the engagement portion 52 of the driver 50 and the groove or hole on the top surface of the head of the screw 211 can be correctly fitted.

  In the present embodiment, the example in which the driver unit 50 is tilted by the angle θ with respect to the y-axis to determine whether or not the engaging portion 52 of the driver unit 50 and the screw 211 are correctly fitted is described. However, depending on the application, for example, when the depth of the fitting portion of the head portion of the screw 211 is shallow, the engagement portion 52 and the screw of the driver unit 50 are not inclined without tilting the driver unit 50 with respect to the y axis. You may make it discriminate | determine whether 211 is correctly fitted. In this case, the image data for performing template matching in the storage unit 106 is image data in a state where the engagement unit 52 of the driver unit 50 and the screw 211 are correctly fitted when the driver unit 50 is not tilted. May be stored. Alternatively, the image data for performing template matching is stored in the storage unit 106 in a state where the engagement unit 52 of the driver unit 50 and the screw 211 are not properly fitted when the driver unit 50 is not tilted at a predetermined angle. The image data may be stored.

  In the present embodiment, as shown in FIGS. 7, 8, and 11, the example in which the driver unit 50 is moved at a constant speed after sudden acceleration and then suddenly decelerated is described. Is not necessary. Alternatively, the driver unit 50 may be moved at a constant speed after rapid acceleration. Alternatively, after the driver unit 50 is moved at a constant speed, the driver unit 50 may be decelerated suddenly and not suddenly accelerated. That is, the driver unit 50 may perform either one of sudden acceleration or sudden deceleration.

  Further, in the present embodiment, the example in which the screw posture is discriminated based on the image data after the driver unit 50 is accelerated at a constant speed and then moved at a constant speed and then rapidly decelerated. However, after determining the screw posture, when the engaging portion 52 of the driver unit 50 and the screw 211 are not properly fitted, the control unit 100 moves the driver unit 50 again at a constant speed. Alternatively, rapid deceleration may be performed. In this case, the position at which the screw posture is determined may not be directly above the screw hole 311 of the object 301 to which the screw 211 is tightened, but at a position before or before the screw hole 311. Alternatively, the position where the screw posture is determined is determined immediately above the screw hole 311 of the object 301 to which the screw 211 is tightened. After the determination, only when the engaging portion 52 of the driver unit 50 and the screw 211 are not properly fitted, the control unit 100 moves the driver unit 50 by a predetermined distance at a constant speed, and then tightens the screw 211. Control may be performed to return the object 301 to the position immediately above the screw hole 311, and rapid deceleration may be performed when the object 301 is returned.

In the present embodiment, a screwdriver having a plus-shaped hole is used as the driver unit 50 and a screw having a plus-shaped hole as the screw 211, but the same effect can be obtained by using other screws. For example, in the case of a screw having a slot (minus), the arm control unit 104 of the control unit 100 uses the image data picked up by the image pickup device 60 and uses the screw on the rail 201 of the pick-up unit of the automatic screw feeder. The angle at which the top surface of the screw head 211 is extracted is extracted. Then, the arm control unit 104 determines the angle of the engagement portion 52 of the driver unit 50 based on the extracted angle of the screw head top surface of the screw 211 and the angle of the screw head top surface of the screw 211. A drive signal is generated to control the rotation speed so as to match. In this way, the angle of the engaging portion 52 of the driver unit 50 may be controlled so as to match the sliding angle of the screw head top surface of the screw 211. Further, the rotational speed for adjusting the angle of the engaging portion 52 of the driver unit 50 to the angle of the top of the screw head of the screw 211 may be calculated by actual measurement, for example.
In the case of a screw having a hexagonal hole, a hexagonal bar wrench is used for the driver bit 51 of the driver unit 50. Even in this case, the control unit 100 may control the hexagonal shape of the engaging portion 52 of the driver unit 50 so as to match the hexagonal shape of the top surface of the screw head of the screw 211.

[Second Embodiment]
In the first embodiment, an example in which the screw hole 311 of the screw tightening target 301 is below the y axis (in the negative direction) and the screw hole 311 is perpendicular to the x axis has been described. The attachment direction of the screw 211 is not limited to the downward direction, and attachment in an arbitrary direction is possible. The arbitrary direction is, for example, a state where the angle θ1 is inclined with respect to the y-axis, as shown in FIG.
FIG. 14 is a flowchart of an operation until the screw 211 is attached to the tip of the driver unit 50 according to the present embodiment and screw tightening is performed. The block of the control unit 100 according to this embodiment is the same as that shown in FIG. 3 shown in the first embodiment.

FIG. 15 is a diagram illustrating a tightening operation of the screw 211 when the screw tightening target 301 according to the present embodiment is tilted. FIG. 15A is a diagram illustrating an operation of returning the driver unit 50 to the original inclination after sudden deceleration. FIG. 15B is a diagram for explaining the operation of pressing the screw 211 against the screw hole 311 of the object 301 to be screwed.
As illustrated in FIG. 14, steps S201 to S209 and S213 are the same as steps S101 to S109 and S114 of the first embodiment, and thus description thereof is omitted.

(Step S210)
After the driver unit 50 stops at the position where the screw tightening is performed, the control unit 100 tilts the driver unit 50 on the xy plane to a predetermined angle θ1 as shown in FIG. The predetermined angle θ1 is an angle θ1 of the inclination of the screw hole 311 of the object 301 to be screwed. After step S210 is completed, the process proceeds to step S211.

(Step S211)
The image acquisition unit 101 of the control unit 100 acquires image data output from the imaging device 60 and converts the acquired image data into digital data. The image acquisition unit 101 outputs the converted image data to the screw posture determination unit 102.
The screw posture determination unit 102 determines whether the screw 211 is attached to the engagement unit 52 of the driver unit 50 in a correct posture from the image data output from the image acquisition unit 101 by known template matching or the like. . When the screw 211 is attached in the correct posture (step S211; Yes), the process proceeds to step S212. When the screw 211 is not attached in the correct posture (step S211; No), the process proceeds to step S213.

(Step S212)
Next, the control unit 100 moves the driver unit 50 in the negative direction of the y-axis direction and presses the screw 211 against the screw hole 311 of the object 301 to be screwed. By pressing, the electric driver generates torque that rotates the engaging portion 52 of the driver unit 50. For this reason, the control unit 100 performs screw tightening by pressing the screw 211 fitted to the engagement unit 52 of the driver unit 50 against the screw hole 311.

  If the tip of the driver unit 50 is tilted at an angle θ1 and the screw 211 is not displaced due to the magnetic force, it is tilted to an angle larger than the angle θ1 so that the engaging portion 52 of the screw 211 and the driver unit 50 You may make it discriminate | determine whether it is fitting correctly. Then, after the screw posture determination, the inclination of the driver unit 50 may be returned to the angle θ1.

As described above, whether or not the engaging portion 52 of the driver 50 and the hole on the top surface of the screw 211 are correctly fitted is determined based on the inclination of the screw hole 311 of the object 301 to which the screw 211 is attached. Tilt to an angle. As a result, it can be confirmed whether or not the engaging portion 52 of the driver unit 50 and the hole on the top surface of the screw 211 are correctly fitted with each other at the actual inclination angle of the screw hole 311 of the object 301 to which the screw 211 is attached. effective. Further, as a result of the determination, when the engaging portion 52 of the driver unit 50 and the hole on the top surface of the screw 211 are correctly fitted, the screw 211 is left as it is without returning the tilt of the inclined driver unit 50. and there is also an effect that can be tightened into the screw hole 311 of the object 3 01 mounting the screw.
Similarly to the first embodiment, after the top surface of the head of the screw 211 is pressed against the engaging portion 52 of the driver unit 50, the screw 211 is suddenly accelerated and decelerated, so that the screw 211 becomes the tip of the driver unit 50. The shape of the convex portion of the screw and the shape of the concave portion of the screw are guided to the fitting position, and the fitting is performed correctly. As a result, even if a general-purpose screwdriver is used, the engagement portion 52 of the driver 50 and the groove or hole on the top surface of the head of the screw 211 can be correctly fitted.

[Third Embodiment]
In the first embodiment and the second embodiment, an example in which an electric screwdriver is used as the driver unit 50 has been described. In the present embodiment, an example in which a driver is used as the driver unit 50 will be described.
The configuration diagram of the robot 1 is the same as that in FIG. 1, and the driver unit 50 is a driver. The engaging portion 52 of the driver unit 50 is magnetized.

FIG. 16 is a flowchart of the operation until the screw 211 is attached to the tip of the driver unit 50 according to the present embodiment and screw tightening is performed.
Steps S301 to S312 and S315 are performed in the same manner as steps S101 to S112 and S114 of the first embodiment.

(Step S313)
The control unit 100 moves the engagement unit 52 of the driver unit 50 in the negative y-axis direction while rotating the engagement unit 52 in the rotation direction in which the screw 211 is tightened. After step S313 ends, the process proceeds to step S314.
(Step S314)
The arm control unit 104 of the control unit 100 moves the driver unit 50 in the negative y-axis direction and rotates it in the xz plane so that the screw 211 is screwed into the screw hole 311 of the object 301 to be screwed. Further, the control unit 100 determines whether or not the screw 211 has been screwed into the screw hole 311 based on information including a force component and a torque component applied to the end effector 40 of the arm 2 output from the force sensor 30. . Until it is determined that the screw tightening is completed, the arm control unit 104 generates a drive signal for performing the screw tightening, and outputs the generated drive signal to the drive unit 105.

  In the present embodiment, as in the first embodiment, an example in which the screw hole 311 of the screw tightening target 301 is perpendicular to the x-axis has been described. However, if the screw hole 311 is oblique, a step is performed. Steps S301 to S311 are performed in the same manner as steps S201 to S211 of the second embodiment. Then, step S313 may be performed without performing step S312.

  As described above, even when a driver is used as the driver unit 50, after the top surface of the head of the screw 211 is pressed against the engaging portion 52 of the driver unit 50, the driver unit 50 is suddenly moved as in the first embodiment. It accelerates and decelerates rapidly. For this reason, even when the engaging portion 52 of the driver 50 and the hole on the top surface of the screw 211 are not properly fitted, the screw 211 is fastened or decelerated by the rapid acceleration or deceleration of the arm portion 20, so The shape of the convex portion of the screw and the shape of the concave portion of the screw are guided to the fitting position, and the fitting is performed correctly. As a result, even if a general-purpose screwdriver is used, the engagement portion 52 of the driver 50 and the groove or hole on the top surface of the head of the screw 211 can be correctly fitted. Further, since the driver unit 50 is tilted to determine whether or not the engaging portion 52 of the driver unit 50 and the head top surface of the screw 211 are correctly fitted, The hole on the top surface of the head of the screw 211 can be properly fitted.

[Fourth Embodiment]
In the first and second embodiments, an example in which an electric screwdriver is used as the driver unit 50, and in the third embodiment, an example in which a screwdriver is used as the driver unit 50 has been described. The robot 1 may be changed.
FIG. 17 is a perspective view illustrating a schematic configuration of the robot 1a according to the present embodiment.
As shown in FIG. 17, the driver units 50 a to 50 c are set on a driver unit mounting base 80.
The driver units 50a to 50c are electric drivers or drivers with different driver bit 51 shapes.
The storage unit 106 of the control unit 100 stores image data for performing template matching for each of the driver units 50a to 50c in advance.

FIG. 18 is a flowchart of the operation of the robot 1a according to this embodiment.
(Step S401)
The control unit 100 moves the tip of the arm unit 20 to the driver unit mounting base 80 based on the control information stored in the storage unit 106.

(Step S402)
Based on the control information stored in the storage unit 106, the control unit 100 selects and holds one of the driver units 50a to 50c that matches the screw hole of the object to be screwed.

(Step S403)
The screw posture determination unit 102 of the control unit 100 reads image data for performing template matching according to the gripped driver units 50a to 50c.
Hereinafter, steps S404 to S417 are the same as steps S101 to S114 of the first embodiment.

  In the present embodiment, as in the first embodiment, an example in which the screw hole 311 of the screw tightening target 301 is perpendicular to the x-axis has been described. However, if the screw hole 311 is oblique, a step is performed. S404 to S414 are performed in the same manner as steps S201 to S211 of the second embodiment. Then, step S416 may be performed without performing step S415.

  As described above, even if the driver is changed according to the screw 211 as the driver unit 50, after the top surface of the head of the screw 211 is pressed against the engaging portion 52 of the driver unit 50 as in the first embodiment, the driver By rapidly accelerating and decelerating the unit 50, the screw 211 is guided to a position where the shape of the convex portion at the tip of the driver unit 50 and the shape of the concave portion of the screw are fitted, and is correctly fitted. As a result, even if a general-purpose screwdriver is used, the engagement portion 52 of the driver 50 and the groove or hole on the top surface of the head of the screw 211 can be correctly fitted. Further, since the driver unit 50 is tilted to determine whether or not the engaging portion 52 of the driver unit 50 and the head top surface of the screw 211 are correctly fitted, The hole on the top surface of the head of the screw 211 can be properly fitted.

Note that a program for realizing the function of each unit of the control unit in FIG. 3 of the embodiment is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. You may process each part by. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if the WWW system is used.
“Computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), a portable medium such as a CD-ROM, and a USB (Universal Serial Bus) I / F (interface). A storage device such as a USB memory or a hard disk built in a computer system. Further, the “computer-readable recording medium” includes a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or a client. The program may be a program for realizing a part of the above-described functions, or may be a program that can realize the above-described functions in combination with a program already recorded in a computer system.

DESCRIPTION OF SYMBOLS 1, 1a ... Robot 2 ... Arm 10 ... Fixed part 20 ... Arm part 30 ... Force sensor 40 ... End effector
DESCRIPTION OF SYMBOLS 50 ... Driver unit 51 ... Driver bit 52 ... Engagement part 60 ... Imaging device
80: Driver unit bases 82, 83, 85 ... Rotating units 81, 84, 86 ... Refraction unit 100 ... Control unit 101 ... Image acquisition unit 102 ... Screw posture determination unit 103 ... Sensor output acquisition unit 104 ... Arm control unit 105 ... Drive unit 106 ... Storage unit 201 ... Screw 201 ... Rail 301 of the automatic screw feeder take-out unit ... Target unit 311: Screw holes θ, θ1: Tilt angle of driver unit

Claims (9)

The arm portion grips a screwdriver in which the engagement portion of the tip of the driver bit that is fitted into the groove of the screw head is magnetized,
The tip is brought into contact with the groove and the driver is accelerated and moved at a first acceleration, which is a positive acceleration that accelerates in the moving direction of the driver unit, and the driver is accelerated in the moving direction of the driver unit. Decelerate and stop at the second acceleration, which is negative acceleration,
Fitting the groove and the tip;
A robot characterized by that. Tilt the driver before Symbol screw is adsorbed in a predetermined angle, imaging the driver the thread is adsorbed, the head top surface of the engaging portion and the screw of the driver using an image captured The state of fitting with the groove of
When the determination result shows that the engagement portion of the driver and the groove on the top surface of the screw are correctly fitted, the screw groove of the object to be screwed is screwed on the screwdriver. The robot according to claim 1, wherein the robot is screwed by moving toward the position. The predetermined angle is
The robot according to claim 2 , wherein the screw has an angle of a thread groove of an object to be attached. With an imaging device ,
An image when the previous SL imaging device is tilted A over arm portion captured at a predetermined angle, based on the similarity between the template image data, the head top surface of the engaging portion and the screw of the driver The robot according to any one of claims 1 to 3 , wherein a state of fitting with the groove is determined. In a state in which the luer over arm portions have grips the previous SL driver is rotated at a predetermined speed, wherein, characterized in that for pressing the engagement portion of the tip of the driver bit into the groove of the head top surface of the screw The robot according to any one of claims 1 to 4 . Robot according to any one of claims 1 to 5, wherein the driver is an electric screwdriver. A robot control device for controlling a robot,
The robot arm is engaged with a screwdriver that is engaged with the groove on the head of the screw and the engagement portion of the tip of the driver bit is magnetized.
The tip is brought into contact with the groove and the driver is accelerated and moved at a first acceleration, which is a positive acceleration that accelerates in the moving direction of the driver unit, and the driver is accelerated in the moving direction of the driver unit. Decelerate and stop at the second acceleration, which is negative acceleration,
Fitting the groove and the tip;
A robot controller characterized by that. A step of causing the robot to grip a screwdriver with which the engaging portion of the tip portion of the driver bit, which is fitted in the groove of the screw head, is magnetized, by the arm portion;
The robot is moved by accelerating the driver at a first acceleration that is a positive acceleration that accelerates in the moving direction of the driver unit by bringing the tip into contact with the groove and moving the driver to the driver unit. Decelerating and moving at a second acceleration, which is a negative acceleration that accelerates in the direction of movement;
Fitting the groove and the tip to the robot;
A robot control method comprising: A program for causing a computer to execute a process for controlling an arm portion that holds a driver whose engagement portion at the tip of a driver bit is magnetized.
A procedure for fitting a screwdriver with which the engaging portion of the tip portion of the driver bit, which is fitted in the groove of the screw head, is magnetized, by the arm portion;
The tip is brought into contact with the groove and the driver is accelerated and moved at a first acceleration, which is a positive acceleration that accelerates in the moving direction of the driver unit, and the driver is accelerated in the moving direction of the driver unit. A procedure for decelerating and stopping at a second acceleration, which is a negative acceleration, and
A procedure for fitting the groove and the tip;
Robot control program to execute.

Images