JP2017127932A - Robot device, method for controlling robot, method for manufacturing component, program and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in a cost and an installation space.SOLUTION: A robot device 100 comprises: robots 200, 200; a guided member 250 which is supported by the robot 200; a guide member 260 which is supported by the robot 200and guides the guided member 250; and a controller 300 having a control unit which controls motions of the robots 200, 200. The control unit controls motion of the robot 200, thereby positioning the guide member 260 in a position attitude for guiding the guided member 250, and controls motion of the robot 200, thereby causing the robot 200to work for a work object in the state of being guided by the guide member 260.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a robot apparatus having a work robot, a robot control method, a part manufacturing method, a program, and a recording medium.

  In general, an assembly work for assembling an assembly work to an assembly work is performed using a robot configured by attaching a robot hand to the tip of an articulated robot arm. For example, after the assembly work is moved to a work start position above the work to be assembled, the assembly work is performed by moving the assembly work downward from the work start position.

  If the robot is operated at a high speed during this assembly work, the robot hand of the robot is displaced from the target locus due to the vibration of the robot. Due to the displacement of the robot hand, the assembly work gripped by the robot hand comes into contact with the chamfered portion of the work to be assembled.

  When the robot hand is further lowered, the position of the robot hand is corrected by the force received by the assembly work from the chamfered slope by compliance control, and the assembly work is assembled to the work to be assembled. If this chamfer is large, deviation from the target locus of the robot hand can be allowed, but due to restrictions on the function and shape of the product, a chamfered portion may not be sufficiently secured in the part.

  On the other hand, a method has been proposed in which assembly work is performed by pressing a guide hook attached to a robot hand against a separately installed guide rail for guidance (Patent Document 1).

JP-A-1-146669

  However, in the method of Patent Document 1, a unique guide rail is required for the work location. Therefore, when the work robot performs assembly work at a plurality of locations, guide rails for the work locations are required, which increases the cost and installation space. Such a problem may also occur in operations other than the assembly operation, for example, the operation of screwing using a tool.

  Then, an object of this invention is to suppress the increase in cost and installation space.

  The robot apparatus of the present invention supports a work robot, a guided member supported by the work robot, a guide member that guides the guided member, supports the guide member, and sets the position and orientation of the guide member. A drive mechanism, and a control unit that controls the operation of the work robot and the drive mechanism, and the control unit controls the operation of the work robot and performs work on a work target by the work robot. Prior to the work process, a guide positioning process for controlling the operation of the drive mechanism to position the guide member in a position and orientation for guiding the guided member during the work process is executed.

  According to the present invention, since the position and orientation of the guide member can be changed by the drive mechanism, it is not necessary to install the guide member at a plurality of positions, and an increase in cost and installation space can be suppressed.

It is a perspective view which shows the working robot of the robot apparatus which concerns on 1st Embodiment. It is explanatory drawing of the whole robot apparatus which concerns on 1st Embodiment. It is a fragmentary sectional view showing a joint of a robot arm. It is a block diagram which shows the structure of the control apparatus of the robot apparatus which concerns on 1st Embodiment. (A) is a perspective view which shows the robot hand which hold | gripped the guide member of the robot apparatus which concerns on 1st Embodiment, a to-be-guided member, and an assembly | attachment workpiece | work. (B) is a top view which shows the robot hand which hold | gripped the guide member of the robot apparatus, the to-be-guided member, and the assembly | attachment workpiece | work seen in the arrow D direction in (a). It is a flowchart which shows a one part process of the manufacturing method of the component which concerns on 1st Embodiment. It is a flowchart which shows a one part process of the manufacturing method of the component which concerns on 1st Embodiment. It is a graph which shows the force sensor value at the time of assembling work. It is a perspective view which shows the robot hand which hold | gripped the guide member of the robot apparatus which concerns on 2nd Embodiment, a to-be-guided member, and an assembly | attachment workpiece | work. It is a flowchart which shows a one part process of the manufacturing method of the component which concerns on 2nd Embodiment. It is a perspective view for demonstrating the positional relationship of a guide member and a to-be-guided member. It is a side view which shows the guide member and the to-be-guided member seen in the arrow E direction of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a perspective view showing a work robot of the robot apparatus according to the first embodiment. FIG. 2 is an explanatory diagram of the entire robot apparatus according to the first embodiment. Note that the work W1 that is the work target is a ring-shaped member, for example, and the work W2 that is the work target is a member having a projection portion into which the ring-shaped member is fitted, for example.

The robot apparatus 100 includes a robot 200 ₁ as a working robot, a robot 200 ₂ as a drive mechanism (auxiliary robot), a control unit 300 for controlling the operation of the robot ₂₀₀ 1, 200 _2. That is, the robot apparatus 100 includes a double-arm robot. The robot apparatus 100 includes an imaging device 400 and an image processing device 500 as measurement units, and a teaching pendant 700 as a teaching unit. In FIG. 1, only one of the dual arm robots is shown. Robot ₂₀₀ 1, 200 ₂ has the same configuration, the following describes the configuration of the robot 200 _1, is omitted description of the configuration of the robot 200 _2.

Robot 200 ₁ includes a robot arm 201 of the vertical articulated, has attached to the end of the robot arm 201, the robot hand 202 as the end effector is a hand of the robot 200 _1, a.

The robot 200 ₁ disposed between the tip and the robot hand 202 of the robot arm 201 has a force sensor 203 as the detecting unit. Therefore, the robot hand 202 is attached to the tip of the robot arm 201 via the force sensor 203.

  In the robot arm 201, a base portion (base end link) 210 fixed to the pedestal 150 and a plurality of links 211 to 216 that transmit displacement and force are connected to be able to swing (turn) or rotate at joints J1 to J6. Has been. In the first embodiment, the robot arm 201 is composed of six-axis joints J1 to J6, which are three axes that swing and three axes that rotate. Here, the swinging joint is called a swinging part, and the rotating joint is called a rotating part. The robot arm 201 includes six joints J1 to J6. The joints J1, J4, and J6 are rotating parts, and the joints J2, J3, and J5 are swinging parts.

  Each joint J1 to J6 of the robot arm 201 is provided with a driving device. As the driving devices for the joints J1 to J6, those having appropriate outputs are used in accordance with the required torque.

  The robot hand 202 has a hand main body 220 and a plurality of fingers 221 supported by the hand main body 220 so as to be opened and closed. The hand body 220 includes a drive device (not shown) that drives the plurality of fingers 221, an encoder (not shown) that detects a rotation angle of the drive device (not shown), and a mechanism (not shown) that converts rotation into a gripping operation. doing. This mechanism (not shown) is designed in accordance with a gripping operation required by a cam mechanism or a link mechanism. The torque required for a driving device (not shown) used for the robot hand 202 is different from that for the joint of the robot arm 201, but the basic configuration is the same.

  By closing the plurality of fingers 221, it is possible to grip the workpiece W <b> 1 that is an assembly work (first workpiece), and by opening the plurality of fingers 221, the workpiece W <b> 1 can be gripped and released. it can. The robot hand 202 can perform an assembling operation for assembling the workpiece W1 to the workpiece W2 to be assembled (second workpiece) by gripping the workpiece W1 using a plurality of fingers 221. The assembled part W0 is manufactured by the assembling work.

The force sensor 203 detects the force applied to the robot 200 ₁ of the hand (i.e. the robot hand 202). The force sensor 203 is a 6-axis force sensor, and the force to be detected includes a force component of three axes of the X axis, the Y axis, and the Z axis, and a moment component around each axis.

  The imaging device 400 is a digital camera. The imaging apparatus 400 includes an imaging sensor 401 such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The imaging device 400 is fixed to the gantry 150 so as not to move with respect to the gantry 150 (the base portion 210 of the robot arm 201). The imaging device 400 images a subject within an imaging range (within an angle of view). In the first embodiment, the robot hand 202 and the workpiece W1 held by the robot hand 202 are subjects. The image processing device 500 processes the image picked up by the image pickup device 400 and obtains the position and orientation of the workpiece W1 with respect to the robot hand 202. In the first embodiment, the imaging device 400 and the image processing device 500 constitute a measuring device 600 that is a measuring unit. That is, the measuring apparatus 600 measures the position and orientation of the workpiece W1 held by the robot hand 202 with respect to the robot hand 202.

  The teaching pendant 700 is configured to be connectable to the control device 300. When connected to the control device 300, the teaching pendant 700 can transmit drive commands for controlling the robot arm 201 and the robot hand 202 and teaching point data to the control device 300. It is configured.

  The robot arm 201 is provided with a driving device for driving the joints at the joints J1 to J6. Hereinafter, in the robot arm 201, the joint J2 will be described as an example, and the other joints J1, J3 to J6 may be different in size and performance, but the description is omitted because they have the same configuration. .

  FIG. 3 is a partial cross-sectional view showing the joint J2 of the robot arm 201. As shown in FIG. The drive device 10 includes a rotary motor (hereinafter referred to as “motor”) 141 that is an electric motor, and a speed reducer 143 that decelerates the rotation of the rotary shaft 142 of the motor 141.

  The motor 141 is a servo motor, for example, a brushless DC servo motor or an AC servo motor.

  An encoder 161 that detects the rotation angle of the motor 141 is disposed on the rotation shaft 142 of the motor 141 (that is, the input shaft of the speed reducer 143). An encoder 162 that detects the rotation angle of the output shaft of the speed reducer 143, that is, the angle of the joint J2, is disposed on the output shaft of the speed reducer 143.

  The encoder 161 is preferably an absolute rotary encoder, and includes an absolute angle encoder for one rotation, a counter for the total number of rotations of the absolute angle encoder, and a backup battery for supplying power to the counter. Even if the power supply to the robot arm 201 is turned off, if the backup battery is valid, the total number of rotations is held in the counter regardless of whether the power supply to the robot arm 201 is on or off. Therefore, the posture of the robot arm 201 can be controlled.

  The encoder 162 is a rotary encoder that detects a relative angle between two adjacent links. In the joint J2, the encoder 162 is a rotary encoder that detects a relative angle between the link 211 and the link 212. The encoder 162 has a configuration in which an encoder scale is provided in the link 211 and a detection head is provided in the link 212, or the reverse configuration.

  Further, the link 211 and the link 212 are swingably connected via a cross roller bearing 147.

  The reducer 143 is, for example, a wave gear reducer that is small and light and has a large reduction ratio. The speed reducer 143 includes a web generator 151 that is an input shaft coupled to a rotating shaft 142 of the motor 141, and a circular spline 152 that is an output shaft fixed to the link 212. The circular spline 152 is directly connected to the link 212, but may be formed integrally with the link 212.

  The reducer 143 includes a flex spline 153 that is disposed between the web generator 151 and the circular spline 152 and fixed to the link 211. The flex spline 153 is decelerated at a reduction ratio N with respect to the rotation of the web generator 151 and rotates relative to the circular spline 152. Accordingly, the rotation of the rotating shaft 142 of the motor 141 is decelerated by the reduction gear 143 at a reduction ratio of 1 / N, and the link 212 having the circular spline 152 fixed relative to the link 211 to which the flexspline 153 is fixed is relative. The joint J2 is swung.

  At least one of the encoder 161 and the encoder 162 arranged in each joint J1 to J6 is a position detection unit. That is, the position and orientation of the hand of the robot can be calculated (detected) based on the values of the encoder 161 or the encoder 162 of each joint J1 to J6.

  FIG. 4 is a block diagram illustrating a configuration of the control device of the robot apparatus according to the first embodiment. The control device 300 includes a CPU (Central Processing Unit) 301 as a control unit (processing unit). The control device 300 includes a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, and an HDD (Hard Disk Drive) 304 as storage units. The control device 300 also includes a recording disk drive 305 and various interfaces 311 to 314.

  A ROM 302, a RAM 303, an HDD 304, a recording disk drive 305, and various interfaces 311 to 314 are connected to the CPU 301 via a bus 310. The ROM 302 stores basic programs such as BIOS. A RAM 303 is a storage device that temporarily stores various types of data such as arithmetic processing results of the CPU 301.

  The HDD 304 is a storage device that stores arithmetic processing results of the CPU 301 and various data acquired from the outside, and records a program 340 for causing the CPU 301 to execute various arithmetic processing described later. The CPU 301 executes each process of the robot control method (manufacturing method of the component W0) based on the program 340 recorded (stored) in the HDD 304.

  The recording disk drive 305 can read various data and programs recorded on the recording disk 341.

Robot 200 ₁ is connected to the interface 311, the robot 200 ₂ are connected to the interface 312. Thus, CPU 301, each robot ₂₀₀ 1, 200 ₂ to the drive command (joint command) can control the output to the operation of the robots ₂₀₀ 1, 200 _2, various sensors from the robot ₂₀₀ 1, 200 ₂ The detection signal can be acquired.

The image processing apparatus 500 is connected to the interface 313, and image processing a captured image of the imaging apparatus 400, and measures the position and orientation of the workpiece W1 (gripping position and gripping orientation) relative to the robot hand 202 of the robot 200 _1, the measurement The result is output to the CPU 301.

  A teaching pendant 700 serving as a teaching unit is connected to an interface 314. The teaching pendant 700 can designate teaching point data for teaching the robot (robot arm 201) by a user input operation. The teaching point data is output to the CPU 301 or the HDD 304 through the interface 314 and the bus 310. The CPU 301 receives input of teaching point data from the teaching pendant 700 or the HDD 305.

  An external storage device (not shown) such as a rewritable nonvolatile memory or an external HDD may be connected to the bus 310 via an interface (not shown).

  In the first embodiment, the case where the computer-readable recording medium is the HDD 304 and the program 340 is stored in the HDD 304 is described, but the present invention is not limited to this. The program 340 may be recorded on any recording medium as long as it is a computer-readable recording medium. For example, as a recording medium for supplying the program 340, the ROM 302 shown in FIG. 4, the recording disk 341, an external storage device (not shown), or the like may be used. As a specific example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory such as a USB memory, a ROM, or the like can be used as a recording medium.

  Here, a tool center point (TCP) is set for the hand of the robot 200, that is, the robot hand 202. TCP has three parameters (x, y, z) representing a position and three parameters (Rx, Ry, Rz) representing a posture, that is, six parameters (x, y, z, Rx, Ry, Rz). It can be regarded as one point on the task space. That is, the task space is a space defined by these six coordinate axes. A teaching point can be designated by this TCP.

  In addition, the teaching point can be specified by a joint angle (configuration). In the first embodiment, since the robot arm 201 has six joints, the teaching point is represented by a configuration (θ1, θ2, θ3, θ4, θ5, θ6) indicating six parameters representing the joint angle, In space, it can be regarded as one point. That is, the joint space is a space defined by these six coordinate axes.

  The teaching point is specified in task space or joint space. The CPU 301 generates path (interpolation path) data of the robot arm 201 that interpolates between teaching points according to the interpolation method specified by the robot program. Here, as interpolation methods for interpolating between teaching points, there are various methods such as linear interpolation, circular interpolation, joint interpolation, Spline interpolation, B-Spline interpolation, and Bezier curve. The path data is a TCP trajectory of the robot arm 201 in the task space or a configuration trajectory of the robot arm 201 in the joint space.

  Then, the CPU 301 calculates trajectory data that defines the operation of the robot arm 201. The trajectory data of the robot arm 201 represents route data using time as a parameter. In the first embodiment, it is a set of TCP position commands or configuration joint commands for each time (for example, every 1 ms). The position command is represented by six parameters (x, y, z, Rx, Ry, Rz), and the joint command is represented by six parameters (θ1, θ2, θ3, θ4, θ5, θ6).

  When the trajectory data is a position command, the CPU 301 finally converts the position command into a joint command indicating the joint angles of the joints J1 to J6 based on inverse kinematics. The operation of the robot arm 201 is controlled by outputting the joint command to the control device of the joint driving device of each of the joints J1 to J6. When the trajectory data is a joint command, the CPU 301 controls the operation of the robot arm 201 by outputting the joint command to the control device of the driving device of each joint J1 to J6.

  As described above, the CPU 301 controls the robot arm 201 using the trajectory data including the drive command (joint command). When controlling the robot arm 201, the CPU 301 selectively performs either semi-closed loop control or full-closed loop control. The semi-closed loop control is feedback control that brings the detected angle of the encoder (input shaft encoder) 161 of each joint J1 to J6 closer to the target angle (command obtained by correcting the joint command with the reduction ratio of the speed reducer 143). Further, the fully closed loop control is feedback control in which the detection angle of the encoder (output shaft encoder) 162 of each joint J1 to J6 is brought close to a target angle (joint command). Since each joint J1 to J6 has a bending member such as a speed reducer 143, full closed loop control is more accurate than semi closed loop control, but responsiveness is higher and higher speed than semi closed loop control. Operation is possible.

Here, the robot 200 ₁ performs the assembly of the workpiece W1 on the workpiece W2 (mating) assembling work (fitting operation). Robot 200 ₂ is to assist the work of the robot 200 _1. The robotic device 100 to the first embodiment, as shown in FIG. 2, the guided member 250 which is supported by the robot 200 ₁ is a working robot, a guide member 260 which is supported to the robot 200 ₂ is an auxiliary robot, It has. That is, the robot 200 _2, supports a guide member 260, it is possible to set the position and orientation of the guide member 260 (changed).

Guided member 250 is fixed robot 200 ₁ of the hand, that is, the robot hand 202 of the robot 200 _1. Guide member 260 is fixed robot 200 ₂ of the hand, that is, the robot hand 202 of the robot 200 _2. The guide member 260 is formed in a shape that linearly guides the guided member 250 in contact therewith.

Since in the first embodiment the robot 200 ₁ has a force sensor 203, which enables compliance control of the robot 200 ₁ during assembly work. Of the robot 200 ₁ and the robot 200 ₂ may have at least one of a force sensor 203, it is also possible to perform the compliance control of the robot 200 ₁ by the force sensor 203 of the robot 200 _2.

  FIG. 5A is a perspective view showing the robot hand that holds the guide member, the guided member, and the assembly work of the robot apparatus according to the first embodiment. FIG. 5B is a plan view showing the robot hand that holds the guide member, the guided member, and the assembly work of the robot device viewed in the direction of arrow D in FIG.

  The guided member 250 is a sphere having a spherical contact surface that can contact the guide member 260. In the first embodiment, the guided member 250 is fixed to the hand body 220 of the robot hand 202 so that the center of the spherical guided member 250 is positioned on the detection axis of the detection value Fy of the force sensor 203. Has been.

  The guide member 260 has an L-shaped cross section so as to come into contact with the guided member 250 at two locations. The guide member 260 is formed to extend in a guide direction (longitudinal direction) perpendicular to the cross section so as to linearly guide the guided member 250 to the assembly position. That is, the guide member 260 is formed in a V-groove shape.

The V-groove angle θ necessary for the guided member 250 to be guided into the guide member 260 is determined from the friction coefficient between the guided member 250 and the guide member 260 as follows. μ is a friction coefficient between the guided member 250 and the guide member 260.
tanθ <1 / μ

Width H in the lateral direction of the V grooves are spherical diameter, and are determined in consideration of the positional deviation of the robot 200 _1. The length L in the longitudinal direction of the V-groove is longer than the distance that requires the accuracy of the locus when assembling according to the workpiece.

  In FIG. 5A, an alternate long and short dash line A is an ideal trajectory of the workpiece W1 when the workpiece W1 is assembled to the workpiece W2. In FIG. 5A, an alternate long and short dash line C is a locus of the guided member 250 when the guided member 250 operates while being guided by the guide member 260.

Next, a manufacturing method (robot control method) for the component W0 according to the first embodiment will be described. First, a description will be given of each robot ₂₀₀ 1, 200 ₂ of the teaching prior to the actual assembling work. FIG. 6 is a flowchart showing some steps (specifically, a teaching step) of the component manufacturing method according to the first embodiment.

Here, it is assumed that the robot coordinate system sigma _R is set to the robot ₂₀₀ 1, 200 _2. Then, the workpiece W2 is to be positioned with high accuracy in the cradle 150, i.e. robot coordinate system sigma _R. The robot program includes a teaching point at the work start position and a teaching point at the work completion position, and data of these teaching points is set by the following teaching. The trajectory between the teaching point at the work start position and the teaching point at the work completion position is created by linear interpolation.

First CPU301 causes hold the workpiece W1 at a position and orientation as a reference with respect to the robot hand 202 of the robot 200 ₁ (S1). That is, the work W1 is gripped by the robot hand 202 so that the work W1 is positioned at a position serving as a reference for the finger 221 of the robot hand 202. For example, the workpiece W1 once gripped by the robot hand 202 is gripped and released in a plane, and the robot hand 202 is gripped again.

Then, CPU 301 is a teaching of using the teaching pendant 700, the fitting axis of the workpiece W1 and workpiece W2 is the same, and to operate the robot 200 ₁ to the work starting position and the workpiece W1 and workpiece W2 are not in contact. That, CPU 301 controls the operation of the robot 200 _1, a workpiece W1 gripped by the position and orientation of the reference relative to the robot hand 202 of the robot 200 _1, is positioned at the operation start position in the robot coordinate system sigma _R ( S2). And the data of the teaching point in the work start position when positioning the workpiece | work W1 is set. Thereby, teaching of the work start position is completed. Similarly, teaching is performed at the work completion position.

Here, a coordinate having the center of the guided member 250 at the work start position as a reference point is defined as a tool coordinate S0. The tool coordinates S0 have a Z axis in a direction parallel to the ideal locus A, a direction perpendicular to the guide locus C, and a direction toward the center of the robot hand 202 as a Y axis. The position and orientation of the robot 200 _first work start position at the time of teaching, a reference position and orientation. An ideal trajectory A is a trajectory in which the work W1 linearly follows the work W2 from the work start position in the assembling direction (Z direction).

Next, the CPU 301 moves the guide member 260 side so that the trajectory C is parallel to the ideal trajectory A and the guide member 260 is in a reference position and orientation in which the guide member 260 comes into contact with the guided member 250 at two points (two places). It operates on the basis of the robot 200 ₂ to the user's teaching (S3). At this time, the center of the V-groove of the guide member 260, it is desirable Y-axis force sensor 203 is teaching the robot 200 ₂ in a state of crossing. In this state, the coordinate of the reference point set for the guide member 260 and coincident with the tool coordinate S0 is set as the tool coordinate T0.

  Next, the case where the assembling work for actually assembling the workpiece W1 to the workpiece W2 will be described. FIG. 7 is a flowchart showing some steps (specifically, assembling work) of the component manufacturing method according to the first embodiment.

First, CPU 301 controls the operation of the robot 200 ₁ to hold the workpiece W1 to the robot hand 202 of the robot 200 ₁ (S11: gripping process, the gripping step). At this time, the workpiece W1 is gripped by the robot hand 202 at a position and orientation serving as a reference with respect to the robot hand 202. For example, after a single workpiece W1 is gripped by the robot hand 202 from a plurality of stacked workpieces W1, the workpiece W1 once gripped by the robot hand 202 is held and released in a plane, and the workpiece is transferred to the robot hand 202 again. Grip W1. In this way, at least two picking operations are required for one workpiece W1, but the workpiece W1 can be held in the same position and orientation with respect to the robot hand 202 each time.

Then CPU301, prior to the next task processing, and controls the operation of the robot 200 _2, the guided member 250 in the position and orientation for guiding the assembling direction when the working process (during working process), the guide member 260 Positioning is performed (S12: guide positioning process, guide positioning step). The assembling direction is the Z-axis direction of the robot coordinate system sigma _R.

To be more specific, CPU 301 operates the robot 200 ₂ to advance the teaching position and orientation in step S3. During this positioning, CPU 301 during operation of the guide member 260 is moved to the guide position, perform a full-closed loop control for the robot 200 _2. Thereby, the guide member 260 can be accurately positioned at the taught guide position. Note that semi-closed loop control may be performed until the guide member 260 approaches the guide position, and switching to full closed loop control in the vicinity of the guide position may be performed.

Further, after positioning, CPU 301 performs a full-closed loop control as encoder 162 of each joint J1~J6 of the robot 200 ₂ becomes a constant value. Thus, even working external force to the robot 200 _2, the position and orientation of the guide member 260 in the robot coordinate system sigma _R is maintained.

Next, CPU 301, as a working process, and controls the operation of the robot 200 _1, to position the workpiece W1 is held by the robot hand 202 to the working start position (S13: work positioning process, work positioning step). During this positioning, the CPU 301 performs semi-closed loop control until the workpiece W1 approaches the work start position, and switches to full closed loop control near the work start position. Since the semi-closed loop control is high response, it is possible to speed up the operation of the robot 200 _1.

In the first embodiment, previously before the workpiece W1 held by the robot hand 202 of the robot 200 ₁ is completed moves to the working start position to operate the advance robot 200 ₂ to the position and orientation of the teaching in the step S3.

Next, CPU 301 controls the operation of the robot 200 _1, while being guided by the guide member 260 performs a work to the work target by the robot 200 ₁ (S14: working process, the working process). To be more specific, CPU 301 is to control the operation of the robot 200 ₁ moves linearly in the assembling direction the workpiece W1 to the operation completion position from the work starting position (Z-axis direction of the coordinate system sigma _R) The workpiece W1 is assembled to the workpiece W2 (assembly process, assembly process). During this assembly process, the guided member 250 is guided to the guide member 260 in the assembly direction.

  In step S <b> 14, the CPU 301 assembles the workpiece W <b> 1 to the workpiece W <b> 2 with the guided member 250 pressed against the guide member 260. More specifically, the CPU 301 lowers the robot hand 202, that is, the guided member 250, in the Z-axis direction, which is the assembly direction, while moving from the + Y-axis direction to the -Y-axis direction in FIG. The work W1 is assembled to the work W2. In this manner, the workpiece W1 is moved in the assembling direction while pressing the guided member 250 against the guide member 260 in a direction intersecting (orthogonal) with the assembling direction in which the workpiece W1 is moved.

The pressing force (pressurization) at this time is preferably a constant value. That is, in the first embodiment CPU301, like to press the guided member 250 such that a force that is detected by the force sensor 203 of the robot 200 ₁ approaches a predetermined value to the guide member 260, and controls the robot 200 _1.

By pressing the guided member 250 against the guide member 260 in this way, the guided member 250 is attracted to the center of the V groove of the guide member 260, and the assembly center of the workpiece W1 and the workpiece W2 becomes the same state. By executing the assembly process by the compliance control functions of the robot 200 _1, it is possible to assemble the workpiece W1 on the workpiece W2 to the high speed.

  FIG. 8 is a graph showing force sensor values when the assembly work is performed. In FIG. 8, time T <b> 1 indicates the timing at which the guided member 250 comes into contact with the guide member 260 and starts the assembly process from the work start position. Time T2 indicates the timing at which the assembly work W1 comes into contact with the assembly work W2. Time T3 indicates the timing at which the work W1 reaches the work completion position. In FIG. 8, the solid line indicates the value of the force sensor 203 when the compliance control is performed, and the broken line indicates the value of the force sensor 203 when the compliance control is not performed.

  During the assembling process, high positional accuracy of the work W1 is particularly required after the assembling work W1 comes into contact with the work to be assembled W2. Therefore, at least from time T2 to time T3, it is preferable to perform feedback control so that the value of the force sensor 203 approaches a constant value (positive value) as shown by the solid line in FIG. The target value of the force sensor 203 may be set based on the force sensor value at the time of the previous assembly operation, or may be set based on a result of an experiment performed in advance.

  In this way, when the workpiece W1 is moved along the ideal trajectory A, since a certain pressure is applied between the guided member 250 and the guide member 260, the guided member 250 is moved during the assembly process. The state where the guide member 260 is in contact can be maintained.

  That is, the guided member 250 is in contact with the guide member 260 by controlling the amount of pushing of the guided member 250 into the guide member 260 by feeding back the force sensor 203 so as to take a positive value. It is guaranteed. Thereby, it is possible to prevent the guided member 250 from moving away from the guide member 260 due to vibration of the robot arm 201 or the like, and the workpiece W1 from deviating from the ideal locus A. Therefore, during the assembly process, the center of the workpiece W1 and the workpiece W2 is guaranteed to be the same, and a highly accurate assembly operation is guaranteed.

As described above, according to the first embodiment, to operate the hand of the robot 200 ₁ along the guide member 260, it is possible to accurately operate even at high speed. Further, the vibration of the hand of the case of operating the robot 200 _at high speed, can be reduced by pressing the guided member 250 in the guide member 260, it is possible to realize a work with high precision set.

  In addition, since the position and orientation of the guide member 260 can be changed, it is not necessary to install the guide member at a plurality of locations when the assembly work is performed at a plurality of locations, thereby suppressing an increase in cost and installation space. be able to.

Although the operation of the robot 200 ₁ becomes slower, in case of moving in the vicinity of the work starting position the workpiece W1 during the positioning of the workpiece W1 to the working start position may also be carried out in full-closed loop control. Since that time the vibration of the robot 200 ₁ is reduced, if it is ensured that the guide member 250 is in contact with the guide member 260, even without compliance control described above during the assembling process Good.

  Further, in the first embodiment, the case where each of the guided member 250 and the guide member 260 is one has been described, but there may be a plurality of guided members 250 for one guide member 260, and the guide member A plurality of pairs of 260 and guided members 250 may be provided.

  In FIG. 7, the case where step S13 (work positioning process) is executed after step S12 (guide positioning process) has been described, but the order is not limited to this. Step S12 may be performed after step S13, or steps S12 and S13 may be performed simultaneously.

[Second Embodiment]
Next, a part manufacturing method (robot control method) by the robot apparatus according to the second embodiment of the present invention will be described. FIG. 9 is a perspective view showing a robot hand that holds the guide member, the guided member, and the assembly work of the robot apparatus according to the second embodiment. Note that the configuration of the robot apparatus according to the second embodiment is the same as the configuration of the robot apparatus according to the first embodiment, and thus the description of the configuration of the robot apparatus is omitted.

  FIG. 10 is a flowchart showing some steps (specifically, assembling work) of the component manufacturing method according to the second embodiment. The teaching process is the same as that in FIG. 6 described in the first embodiment, and a description thereof will be omitted.

In the first embodiment, the robot hand 202 of the robot 200 ₁ case has been described that grips the workpiece W1 at the same position each time the finger 221. In the second embodiment, a case where the robot hand 202 grips the workpiece W1 in a random position and orientation with the finger 221 (so-called random picking) will be described.

  When the robot hand 202 grips one of a plurality of randomly stacked workpieces W1, as shown in FIG. 9, the position and orientation of the workpiece W1 relative to the robot hand 202 is a reference position and orientation (when teaching is performed). (Position and orientation) is different each time.

First CPU301 causes hold the workpiece W1 by controlling the operation of the robot 200 ₁ to the robot hand 202 of the robot 200 ₁ (S21: gripping process, the gripping step). At this time, the workpiece W1 is gripped by the robot hand 202 with a random position and orientation with respect to the robot hand 202. In the second embodiment, it is not necessary to carry out the work of changing the workpiece W1 as in the first embodiment, so that the assembly work can be speeded up as compared with the first embodiment.

Next, the CPU 301 causes the measurement device 600 serving as a measurement unit to measure the position and orientation of the workpiece W1 with respect to the robot hand 202 (S22: measurement process, measurement process). To be more specific, CPU 301 controls the robot 200 ₁ moves the robot hand 202 gripping the workpiece W1 in the angle of view of the imaging device 400, thereby image the robot hand 202 and the workpiece W1 to the image pickup device 400. The image processing apparatus 500 performs image processing on the captured image to obtain the position and orientation of the workpiece W1 relative to the robot hand 202, and sends the measurement result to the CPU 301 of the control apparatus 300. As a result, the CPU 301 acquires the position and orientation of the workpiece W1 with respect to the robot hand 202 from the image processing apparatus 500.

CPU301 corrects the operation of the robot 200 ₁ in accordance with the measurement result of the measuring device 600, to position the workpiece W1 to the operation start position (S23: work positioning process, the guide positioning step). CPU301 In detail, the position of the robot hand 202 based on the position and orientation deviation from the position and orientation of the reference of the workpiece W1 with respect to the robot hand 202, the workpiece W1 is the position and orientation when the teaching in the step S2 in the robot coordinate system sigma _R Ask for posture. That is, to correct the data of the robot 200 _first taught point of the work starting position by the measurement result of the measuring device 600 (and the operation completion position). Then, trajectory data is generated based on the corrected teaching point data. Thus, the workpiece W1 to generate the trajectory data of the robot 200 ₁ to follow the trajectory A of the reference (ideal) in the robot coordinate system sigma _R. Then, CPU 301 operates the robot 200 ₁ according to the trajectory data, to position the workpiece W1 to the work starting position. FIG. 9 illustrates a state in which the workpiece W1 is positioned at the work start position.

During this positioning, the CPU 301 performs semi-closed loop control until the workpiece W1 approaches the work start position, and switches to full closed loop control near the work start position. Since the semi-closed loop control is high response, it is possible to speed up the operation of the robot 200 _1.

Here, when correcting the reference to the workpiece W1 by the position and orientation of the robot 200 _1, the robot hand 202 and the guided member 250, the position and orientation relationship between the guide member 260 is different from the state of FIG. 5 (a). Therefore, the guide member 260 are in the original ideal position and orientation when the teaching robot 200 _2, the guide member 260 and the guide member 250 no longer contacts. That is, the guided member 250 cannot be guided by the guide member 260.

Therefore CPU301 corrects the operation of the robot 200 ₂ in accordance with the measurement result of the measuring device 600, the position and orientation for guiding the guided member 250 when attached next set processing assembling direction to position the guide member 260 (S24: Guide positioning process, guide positioning process).

Specifically, first, CPU 301 calculates the working reference position and orientation of the guide member 250 at the start position (tool coordinate) S0 when the teaching robot 200 _1. Further, the CPU 301 determines the actual position and orientation (tool coordinates) of the guided member 250 when it is assumed that the workpiece W1 is positioned at the work start position based on the actual position and orientation of the work W1 with respect to the robot hand 202 measured by the measuring device 600. ) Calculate S1. Then, the CPU 301 calculates a deviation ΔS between the reference position and orientation S0 and the actual position and orientation S1.

Next, CPU 301 is a tool coordinate T0 set for the guide member 260 when teaching in step S3, the corrected based on the deviation [Delta] S, based on the tool coordinate T1 of corrected teaching point at the guide position robot 200 ₂ Correct the data. Then, the CPU 301 generates trajectory data using the teaching point data, and operates the robot 200 ₂ (that is, the guide member 260) to move to the guide position according to the trajectory data. Thereby, the position and orientation of the guide member 260 are corrected following the position and orientation of the guided member 250 when the guide member 260 is positioned at the work start position based on the measurement result.

More specifically, the CPU 301 corrects the tool coordinate T0 of the guide member 260 when teaching is performed using the (x, y, z, tz) component of the deviation ΔS. The corrected tool coordinates T1 are as follows.
T1 = T0 (x0, y0, z0, tx0, ty0, tz0) + ΔS (x, y, z, 0, 0, tz)

  That is, in the second embodiment, the workpiece W1 is linearly moved from the work start position to the work completion position. Therefore, in step S24, the CPU 301 positions the guide member 260 in a state where the guide direction (longitudinal direction) of the guide member 260 is parallel to the assembly direction, regardless of the position and orientation of the guided member 250.

In the second embodiment, since the position and orientation of the robot hand 202, i.e. the position and orientation of the guide member 250 is changed by the gripping position of the workpiece W1, the number of the guide members 250 provided in the robot 200 ₂ is one .

  FIG. 11 is a perspective view for explaining the positional relationship between the guide member and the guided member, and FIG. 12 is a side view showing the guide member and the guided member viewed in the direction of arrow E in FIG.

As shown in FIGS. 11 and 12, by positioning the guide member 260 by operating the robot 200 _{and second} guide member 260 side to the guide position correction, contact between the guide member 250 and the guide member 260.

During this positioning, CPU 301 during operation of the guide member 260 is moved to the guide position, perform a full-closed loop control for the robot 200 _2. Thereby, the guide member 260 can be accurately positioned at the teaching position. Note that semi-closed loop control may be performed until the guide member 260 approaches the guide position, and switching to full closed loop control in the vicinity of the guide position may be performed.

Next, CPU 301 controls the operation of the robot 200 ₁ performs work work target (S24: working process, the working process). To be more specific, CPU 301 is to control the operation of the robot 200 ₁ moves linearly in the assembling direction the workpiece W1 to the operation completion position from the work starting position (Z-axis direction of the coordinate system sigma _R) The workpiece W1 is assembled to the workpiece W2 (assembly process, assembly process).

  In step S24, the CPU 301 assembles the workpiece W1 to the workpiece W2 in a state where the guided member 250 is pressed against the guide member 260. The pressing force (pressurization) at this time is preferably a constant value.

  As described above, the guided member 250 moves in the Z-axis direction as the assembling direction while applying a certain residual pressure to the guide member 260, so that the guided member 250 operates on the guide locus C ′, and the workpiece W1. Operates along an ideal trajectory A.

At this time, the CPU 301 corrects the detection value of the force sensor 203 based on the (tx, ty) component of the deviation ΔS as shown in the following formula so that a constant pressure is applied in the Fy direction. Control the amount of push.
Fy = fy × cos (tx) + fz × sin (tx)> 0

By this control, regardless of the posture of the robot 200 _1, even when the robot is operated 200 ₁ at high speed, it is possible to suppress the vibration of the robot 200 _1, it can operate with high precision set Become.

Although the operation of the robot 200 ₁ becomes slower, in case of moving in the vicinity of the work starting position the workpiece W1 during the positioning of the workpiece W1 to the working start position may also be carried out in full-closed loop control. Since that time the vibration of the robot 200 ₁ is reduced, if it is ensured that the guide member 250 is in contact with the guide member 260, even without compliance control described above during the assembling process Good.

  In FIG. 10, the case where step S24 (guide positioning process) is executed after step S23 (work positioning process) has been described, but the order is not limited to this. Step S23 may be performed after step S24, or steps S23 and S24 may be performed simultaneously.

  The present invention is not limited to the embodiments described above, and many modifications are possible within the technical idea of the present invention. In addition, the effects described in the embodiments of the present invention only list the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

  A program that realizes one or more functions of the above-described embodiments is supplied to a system or apparatus via a network or a storage medium, and is also realized by a process in which one or more processors in a computer of the system or apparatus read and execute the program Is possible. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

  Moreover, although the above-mentioned embodiment demonstrated the case where the control part was comprised by one computer (CPU), the control part may be comprised by several computer (CPU).

  In the above-described embodiment, the case where the robot arm is a vertically articulated robot arm has been described. However, the present invention is not limited to this. The robot arm may be various robot arms such as a horizontal articulated robot arm, a parallel link robot arm, and an orthogonal robot.

  In the above-described embodiment, the case where the measurement unit includes the imaging device and the image processing device has been described. However, any measurement device may be used as long as the position and orientation of the workpiece with respect to the robot hand can be measured. For example, the measurement unit may be a laser displacement meter.

  In the above-described embodiment, the case where the work robot has a force sensor that is a force detection unit has been described. However, the auxiliary robot may have a force detection unit. In this case, since the force detection unit is not essential for the work robot, the weight of the robot hand of the work robot is reduced, the operation speed of the work robot can be further improved, and the cycle time can be shortened. In addition, since the weight of the robot hand is reduced, heavier workpieces can be transported.

  In the above-described embodiment, the case where the work to be performed by the work robot is an assembly work has been described. However, the present invention is not limited to the assembly work. For example, the work robot is performed using a tool (for example, a driver). It may be work. Moreover, although the case where the assembling work is a fitting work has been described, the present invention is not limited to this. For example, a labeling work for causing a work robot to perform labeling may be used. In this case, the work to be assembled is a label, and the work robot attaches a label to the work to be assembled.

  In the above-described embodiment, the case is described in which the guide member is fixed to the robot hand of the auxiliary robot. However, the present invention is not limited to this, and the guide member may be held by the robot hand of the auxiliary robot. Good.

  In the above-described embodiment, the case where the drive mechanism is an auxiliary robot has been described. However, the mechanism is not limited to the robot, and any mechanism can be used as long as the guide member can be supported and the position and orientation of the guide member can be changed. It may be.

100 ... robot, 200 1 _... robot (work robot), 200 2 _... robot (drive mechanism, the auxiliary robot), 250 ... the guided member, 260 ... guide member, 301 ... CPU (control unit), W1 ... workpiece (set Attached work), W2 ... work (work to be assembled)

Claims (17)

A working robot,
A guided member supported by the work robot;
A guide member for guiding the guided member;
A drive mechanism that supports the guide member and sets the position and orientation of the guide member;
A control unit for controlling the operation of the work robot and the drive mechanism,
The controller is
A work process for controlling the operation of the work robot and performing work on a work object by the work robot;
Prior to the work process, a robot apparatus that performs an operation of the drive mechanism to perform a guide positioning process for positioning the guide member in a position and orientation for guiding the guided member during the work process. The working robot has a robot arm and a robot hand attached to the tip of the robot arm,
The controller is
Further controlling the operation of the work robot, further executing a work positioning process for positioning the assembled work held by the robot hand at a work start position;
2. The assembly process according to claim 1, wherein as the work process, an operation of the work robot is controlled to perform an assembly process in which the assembly work is moved in the assembly direction from the work start position and assembled to the work to be assembled. Robot device.   The robot apparatus according to claim 2, wherein in the assembly process, the control unit assembles the assembly work to the assembly work in a state where the guided member is pressed against the guide member. A measuring unit that measures the position and orientation of the assembled workpiece with respect to the robot hand;
The said control part correct | amends the operation | movement of the said work robot according to the measurement result of the said measurement part in the said workpiece positioning process, and positions the said assembly | attachment workpiece | work in the said work start position. Robot device.   In the guide positioning process, the control unit corrects the operation of the drive mechanism in accordance with the measurement result of the measurement unit, so that the guided member is guided in the assembly direction during the assembly process. The robot apparatus according to claim 4, wherein the guide member is positioned.   The said control part controls the operation | movement of the said working robot prior to the said workpiece positioning process, and performs further the holding | grip process which makes the said robot hand hold | grip the said assembly | attachment workpiece | work. The robot apparatus described.   The robot apparatus according to claim 2, wherein the drive mechanism is an auxiliary robot that supports the guide member.   The robot apparatus according to claim 7, wherein the guide member is fixed to a hand of the auxiliary robot.   The robot apparatus according to claim 7 or 8, wherein the guided member is fixed to a hand of the work robot. The auxiliary robot or the work robot has a detection unit that detects a force applied to a hand.
The robot apparatus according to claim 7, wherein the control unit presses the guided member against the guide member so that a force detected by the detection unit approaches a constant value. The guide member has an L-shaped cross section so as to come into contact with the guided member at two locations,
11. The robot apparatus according to claim 2, wherein the control unit positions the guide member in a state in which a direction perpendicular to the cross section is parallel to the assembly direction in the guide positioning process.   The robot apparatus according to claim 11, wherein the guided member has a spherical contact surface that can come into contact with the guide member.   The robot apparatus according to claim 11, wherein the work robot is provided with a single guided member. A robot control method for controlling operations of a work robot to which a guided member is attached and a driving mechanism for supporting a guide member for guiding the guided member and changing a position and orientation of the guided member by a control unit. ,
The control unit controls the operation of the work robot and performs a work on a work target by the work robot; and
A guide positioning step for controlling the operation of the drive mechanism prior to the work step so that the guide member is positioned in a position and orientation for guiding the guided member during the work step; Robot control method. The operation of the work robot to which the guided member is attached and the drive mechanism that supports the guide member that guides the guided member and changes the position and orientation of the guide member are controlled by the control unit. A manufacturing method for manufacturing a part by:
The control unit controls the operation of the work robot and performs a work on a work target by the work robot; and
A guide positioning step for controlling the operation of the drive mechanism prior to the work step so that the guide member is positioned in a position and orientation for guiding the guided member during the work step; A manufacturing method for parts.   The program for making a computer perform each process of the robot control method of Claim 14.   The computer-readable recording medium which recorded the program of Claim 16.

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