JP2014121771A - Robot device and articulated robot control method - Google Patents

Abstract

A robot apparatus capable of easily inserting one of an inner member and an outer member having an inner peripheral surface that can be inserted into the inner member into the other, and a method for controlling the robot apparatus.
An articulated robot, a force sensor 22 capable of detecting a reaction force received by the articulated robot, and an annular part W2 gripped by the articulated robot are inserted into a conical workpiece body W1. When performing the operation, the annular component W2 is moved in a designated trajectory created based on the first coordinate system 118 set for the annular component W2 held by the articulated robot, and the annular component W2 is moved to the workpiece body W1. When the force sensor 22 detects the reaction force in contact with the second coordinate system Q along the inclination direction for moving the annular component W2 along the inclination direction of the outer peripheral surface of the work body W1 from the reaction force. Is set as a contact point of the annular part W2, and a controller for moving and controlling the articulated robot holding the annular part W2 in the second coordinate system Q is provided.
[Selection] Figure 5

Description

  The present invention relates to a robot apparatus including an articulated robot having a force sensor and a method for controlling the articulated robot.

  In recent years, industrial robots have been used for various purposes, and recently, they are increasingly used in assembly lines for automatically assembling parts. Among them, articulated robots are introduced in many assembly lines because they have the freedom to perform the same movements as humans.

  However, articulated robots can take various postures compared to robots with excellent reproducibility of planar position, such as SCARA robots and direct robots, but the degree of freedom increases, and the reproducibility of postures varies. Occurs. For this reason, articulated robots sometimes fail to assemble components such as fitting and insertion on an assembly line, and many articulated robots compensate for posture reproducibility through feedback control using force sensors. (See Non-Patent Document 1).

  Here, feedback control using a force sensor is performed by attaching a force sensor to the tip of a robot arm, detecting an external force generated by contact or the like as a force in each axis vector direction of the force sensor, and positioning the position relative to that direction. Make corrections. The position correction is performed every sampling period, and is performed by a correction means that calculates the determined force as a position correction amount based on the spring constant and viscosity coefficient that are set parameters, and operates in a direction that relaxes the force. is there. By incorporating feedback control using a force sensor, it is possible to prevent the assembly of parts from failing due to deviations due to tolerances of the assembled parts and reproducibility of the posture of the robot during operation.

  However, for example, when assembling an annular part to a substantially conical work body, if it is necessary to maintain a constant contact state with the slope of the work body while maintaining the annular part in a constant posture, the slope direction of the work body is changed. Recognize and move the ring part to the recognized slope direction. In response to this, teaching is performed at a rough interval on the slope, and the operation is performed in a constant contact state with respect to the slope based on the detection value detected by the force sensor when the slope is touched when performing this check operation. A robot apparatus for creating teaching points is proposed (see Patent Document 1).

New edition of Robotics Handbook 2.4.2 Force control P287-295

JP-A-5-265537

  However, the robot apparatus described in Patent Document 1 protects the trajectory interpolation point at the time of teaching, and in advance for an object with an irregular path whose slope direction changes individually in actual operation. Cannot respond because it cannot be taught. For example, when the annular part is assembled to the inclined surface of the cone-shaped workpiece body as described above, the contact with the inclined surface of the workpiece body can occur at any position on the inner periphery of the annular component. There was a problem that I could not.

  Therefore, the present invention provides a robot apparatus and a control method for an articulated robot in which one member of an inner member and an outer member having an inner peripheral surface that can be inserted into the inner member can be easily inserted into the other member. The purpose is to do.

  The present invention relates to an articulated robot, a force sensor capable of detecting a reaction force received by the articulated robot, an inner member having an outer peripheral surface gripped by the articulated robot, and the inner member. The first coordinates set for the one member held by the multi-joint robot when performing an insertion operation in which any one of the outer members having an insertable inner peripheral surface is inserted into the other member The outer member is relatively moved from a small diameter portion to a large diameter portion of the inner member in a designated trajectory created based on a system, and the one member held by the articulated robot contacts the other member Then, when the force sensor detects the reaction force, the tilt direction for moving the one member gripped by the articulated robot from the reaction force along the tilt direction of the outer peripheral surface of the inner member. A control device that sets the second coordinate system along the one member gripped by the articulated robot and moves and controls the articulated robot gripping the one member in the second coordinate system. It is characterized by that.

  According to the present invention, there is provided a robot apparatus and an articulated robot control method capable of easily inserting one member of an inner member and an outer member having an inner peripheral surface that can be inserted into the inner member into the other member. can do.

1 is a perspective view schematically showing an overall structure of a robot apparatus according to a first embodiment of the present invention. It is a block diagram of the control apparatus which controls the articulated robot which concerns on 1st Embodiment. It is a figure which shows the insertion of the annular component by the multi joint robot which concerns on 1st Embodiment to the workpiece | work main body. It is a flowchart which shows the insertion operation | movement by the articulated robot which concerns on 1st Embodiment to the workpiece | work main body of the annular component. It is a figure for demonstrating the locus | trajectory calculation of the articulated robot when an annular component contacts the workpiece | work main body in the middle of insertion of an annular component. It is a figure which shows the state which the robot apparatus which concerns on 2nd Embodiment fits a ring component to a workpiece | work main body. It is a perspective view which shows the insertion of the square ring component to the workpiece | work main body by the articulated robot concerning 3rd Embodiment. FIG. 10 is a top view of parts having different shapes held by an articulated robot according to a third embodiment. It is a top view which shows the insertion order of the square ring components which the articulated robot which concerns on 3rd Embodiment is holding | gripping. It is a perspective view which shows the insertion of the square ring component to the workpiece | work main body by the articulated robot concerning 4th Embodiment. It is a flowchart which shows the insertion operation | movement by the articulated robot which concerns on 4th Embodiment to the workpiece | work main body of the rectangular ring component. It is a top view which shows the insertion order of the square ring components which the articulated robot which concerns on 4th Embodiment has hold | gripped.

<First Embodiment>
Hereinafter, a robot apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, a schematic configuration of the entire robot apparatus according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view schematically showing the overall structure of the robot apparatus 1 according to the first embodiment of the present invention. FIG. 2 is a block diagram of the control device 3 that controls the articulated robot 2 according to the first embodiment. The work body W1 according to the first embodiment is an inner member whose outer peripheral surface is conical, and the annular part W2 is an outer member having a cylindrical inner peripheral surface that can be inserted into the work body W1.

  As shown in FIG. 1, the robot apparatus 1 includes an articulated robot 2 that assembles an annular part W2 as an outer member to a work body W1 as an inner member, and a control apparatus 3 as a control unit that controls the articulated robot 2. And.

  The articulated robot 2 includes a 6-axis articulated robot arm 20, an end effector 21 connected to the tip of the robot arm 20, and a force sensor 22 disposed between the robot arm 20 and the end effector 21. It is equipped with. In the present embodiment, the force sensor 22 is a constituent element of the articulated robot 2, but may be a constituent element of the robot apparatus 1.

  The robot arm 20 includes six actuators (not shown) that rotationally drive each joint around each joint axis. By selectively driving each of the six actuators, the end effector 21 can be moved to any 3 Move to dimension position. The end effector 21 includes a plurality of fingers 21a, and grips a workpiece (annular component W2 in the present embodiment) with the plurality of fingers 21a. The force sensor 22 is configured to be able to detect the forces and moments in the three axial directions that are generated when the annular part W2 held by the finger 21a contacts the work body W1 during the assembly.

  As shown in FIG. 2, the control device 3 includes a trajectory generation unit 30, a trajectory storage unit 31, a control command unit 32, a correction calculation unit 33, a contact determination unit 34, a coordinate calculation unit 35, and not illustrated. A posture control unit. The trajectory generating unit 30 generates a target trajectory as a designated trajectory of the robot arm 20 based on a first coordinate system set in advance at an arbitrary position of the annular component W2 (the hand of the articulated robot 2). The trajectory storage unit 31 stores the target trajectory generated by the trajectory generation unit 30. The control command unit 32 performs calculation as each axis command value in various limits of the robot arm 20 based on the position command value stored in the trajectory storage unit 31 and the current position of the robot arm 20 fed back. The robot arm 20 is feedback-controlled. When the reaction force (hereinafter referred to as “force value”) is input from the force sensor 22 by the feedback control of the control command unit 32, the correction calculation unit 33 is based on the force value and the position correction amount. Calculate

  The contact determination unit 34 performs contact determination based on a predetermined threshold value from the force value input from the force sensor 22. That is, in the present embodiment, the control device 3 adds the contact condition when the contact is determined by the contact determination unit 34 in addition to the feedback control by the control command unit 32. When contact is determined by the contact determination unit 34, a force sense value at the time of contact determination is input to the coordinate calculation unit 35 in order to calculate a second coordinate system that defines the traveling direction along the slope direction of the work body W1. The coordinate calculation unit 35 creates the second coordinate system of the robot arm 20 with the traveling direction in the slope direction and the axial direction defined in the vertical drag direction from the force value at the time of contact determination. The posture control unit performs posture control of the multi-joint robot 2 so that the annular component W2 maintains a fixed posture when the multi-joint robot 2 performs an insertion operation.

  Further, the control device 3 includes a recording medium reading device that can read a control program recorded on a computer-readable recording medium, and can read and execute the control program recorded on the recording medium. ing.

  Next, an operation of assembling the annular part W2 onto the work body W1 by the articulated robot 2 of the robot apparatus 1 according to the first embodiment (a control program for the articulated robot 2 by the control apparatus 3) will be described with reference to FIGS. Will be described with reference to FIG. FIG. 3 is a diagram illustrating insertion and insertion of the annular component W2 into the work body W1 by the articulated robot 2 according to the first embodiment. FIG. 4 is a flowchart showing an insertion operation of the annular part W2 into the work body W1 by the articulated robot 2 according to the first embodiment.

  As shown in FIG. 3 (a), when the annular component W2 is relatively inserted from the small-diameter portion of the substantially conical work body W1 toward the large-diameter portion, the axial center of the annular component W2 is inserted. When the axis center of the workpiece body W1 coincides, it can be assembled by moving the annular part W2 linearly.

  On the other hand, as shown in FIGS. 3B and 3C, when a shift 113 occurs in the center of each axis due to the influence of the position reproducibility of the articulated robot 2 or the tolerance of the workpiece body W1, the insertion is performed. On the way, the annular part W2 comes into contact with the inclined surface of the work body W1. Therefore, after the contact, it is necessary to operate the annular part W2 along the inclined surface of the work body W1. However, when the annular part W2 having the cylindrical inner peripheral surface is assembled to the work body W1 having the conical outer peripheral surface, the axial center shift 113 can occur on any of the inner peripheral surfaces of the annular part W2. The inclination direction 115 at the contact point becomes indefinite.

  Therefore, the present invention calculates the inclination direction 115 along the outer peripheral surface of the work body W1 at the contact point from the force value at the time of the contact determination, so that the annular part W2 can move along the inclination direction 115. The tilt direction 115 is set as the second coordinate system of the articulated robot 2. Hereinafter, it demonstrates according to the insertion operation | movement of the annular component W2 of the workpiece | work main body W1.

  As shown in FIG. 4, first, when an arbitrary first coordinate system for moving the annular part W2 is set at the hand of the articulated robot 2 (on the annular part W2), the trajectory generating unit 30 sets the first coordinate system. Based on the system, a target trajectory for moving the annular part W2 to the insertion position is created (step S1). The created target trajectory is stored in the trajectory storage unit 31. Next, the control command unit 32 starts movement control of the articulated robot 2 so that the annular part W2 moves according to the target trajectory (step S2), and also starts feedback control based on the detected force sense value. (Step S3). Thereby, an insertion operation is started (an insertion start process).

  When the insertion operation is started, the correction calculation unit 33 calculates the position correction amount when the force value is input. The calculated position correction amount is sent to the control command unit 32. The control command unit 32 calculates each axis command value within the various limits of the robot arm 20 based on the position command value, the current position, and the position correction amount. Based on this calculation, the robot arm 20 is sequentially controlled.

  Here, when the force sensor 22 detects a force value, the contact determination unit 34 makes a contact determination based on a predetermined threshold from the force value input from the force sensor 22. Specifically, the contact determination unit 34 first determines whether the detected haptic value is less than a threshold value (steps S4 and S5). If the detected haptic value is less than the threshold value, it is determined that the annular component W2 is not in contact with the work body W1, and if it has reached the insertion position 106, which is the final arrival position, the control is terminated. If not, the process returns to step S3 (step S9).

  On the other hand, when the detected force value is equal to or greater than the threshold value (N in step S5), the contact determination unit 34 determines that the annular component W2 has contacted the work body W1, and the force calculation value is stored in the coordinate calculation unit 35. Input (reaction force acquisition step, step S6). When a force sense value is input to the coordinate calculation unit 35, the coordinate calculation unit 35 calculates a tilt direction along the outer peripheral surface of the workpiece body W1 from the input force sense value and calculates a second coordinate system ( Coordinate system creation step, step S7). This calculation method will be described in detail later.

  When the second coordinate system is created by the coordinate calculation unit 35, the created second coordinate system is sent to the trajectory generation unit 30 and the correction calculation unit 33, and the trajectory generation unit 30 operates in a new traveling direction. The value is recalculated (orbit resetting step, step S8).

  The recalculated position command value is overwritten with the conventional position command value stored in the trajectory storage unit 31, and the overwritten position command value is sent to the control command unit 32. The correction calculator 33 calculates a position correction amount for the created second coordinate system, and sends the position correction amount to the control command unit 32. When the position correction amount is sent, the control command unit 32 reflects the overwritten position command value, the current value, and the correction amount for the created second coordinate system, and each axis within the various limits of the articulated robot 2. Calculation is performed as a command value, and the articulated robot 2 is controlled. The operation along the second coordinate system calculated by the coordinate calculation unit 35 is executed until the next contact determination is made, and when the next contact determination is made, the coordinate system is updated again to create a new position command value. To do. If the annular component W2 has reached the insertion position 106, the control is terminated, and if not, the process returns to step S3 (insertion end step, step S9).

  At this time, posture control of the articulated robot 2 is performed by the control device 3 so as to maintain a constant posture of the annular component W2, but the description thereof is omitted.

  Next, a method for calculating the trajectory when resetting the trajectory of the articulated robot 2 will be described with reference to FIG. FIG. 5 is a diagram for explaining the trajectory calculation of the articulated robot 2 when the annular part W2 comes into contact with the work body W1 during the insertion of the annular part W2.

  In the present embodiment, both the traveling direction and the force vector are the same direction, which is defined as a conventional first coordinate system 118, and is calculated assuming that the traveling direction is straight ahead with the traveling direction as the Z axis. First, the contact force in the first coordinate system 118 is defined as each vector parallel direction (Fx, Fy, Fz). In this embodiment, a force sensor that detects six axes of translation F = (Fx, Fy, Fz) and moment MF = (MFx, MFy, MFz) is used, and the translation is used.

  In the case of a triaxial force sensor, force components are often output as translation directions Fz, moment directions MFx, MFy. In this case, after converting MFx, MFy into translation directions Fx, Fy, Perform the calculation. First, in order to calculate the direction of the contact point with the axis center as the viewpoint, the resultant force Fxy of Fx and Fy is calculated.

  Next, the angle of the resultant force Fxy calculated above is calculated. This angle is the direction of the contact point of the annular component W2 with respect to the plane centered on the traveling direction and the axis center of the end effector 21 as a viewpoint, and is defined as the rotation angle of the Z axis.

  Next, the vector angle of Fz and resultant force Fxy is calculated. This angle is the direction of the normal force vector 117 with respect to a plane whose normal is the traveling direction, and is defined as the rotation angle of the Y axis for calculating the inclination direction 115 and the inclination direction vector 116.

  Next, the grip center coordinate (conventional first coordinate system 118) is set to P = (Px, Py, Pz), the radius of the ring part W2 to be contacted is r, and the coordinate from the coordinate 0 of the tip mounting surface of the robot arm 20 is coordinated. Let L be the distance to P. Then, the translational component (Qx, Qy, Qz) of the coordinate Q in contact can be expressed by the following equation from the above equation (2).

  If the radius of the annular component W2 is unknown, it can be defined as 0. In this case, a new coordinate system centered on the position on the conventional first coordinate system is created. First, the translation and rotation parameters of the coordinate Q are obtained from the above formulas 2 to 4.

  Next, the coordinate Q is obtained from the parameters of the equation (5). The calculation of the coordinates in the present embodiment is a Euler angle ZYX matrix calculation, and can be obtained by the following equation.

  The result of the coordinate calculation of Equations 6 to 8 from the parameters of Equation 5 is shown below.

  The coordinates obtained from Equation 9 are defined as the second coordinate system Q. The second coordinate system Q is a coordinate with the slope direction vector 116 facing the Z axis and the normal force vector 117 facing the X axis direction.

  Next, the current position teaching point A for the registered second coordinate system Q is created. First, the position from the base coordinate to the second coordinate system Q is calculated by forward kinematics calculation, and the calculated coordinate is newly registered as the current position teaching point A.

  Next, the trajectory up to the insertion position 106 is calculated. First, from the conventional trajectory, the conventional final position is calculated by forward kinematics calculation and registered as the target teaching point B. Next, a moving distance D in the traveling direction between the current position teaching point P and the target teaching point B is calculated. The movement distance D between the PBs is the distance in the Z-axis direction that has been defined as the traveling direction.

  Next, a new teaching point B ′ that is moved from the current position teaching point A in the tilt direction 115 by the moving distance D in the Z-axis direction of the conventional first coordinate system 118 is created. First, the distance R between BB 'is calculated by the following formula.

  From the equations (8) and (10), the parameters of the new teaching point B ′ are as follows.

  The results of coordinate calculation of Equations 6 to 8 from the parameters of Equation 11 are described below.

  The coordinates obtained from the equation (12) are defined as a new teaching point B ′. When the linear interpolation for the second coordinate system Q is performed using the calculated current position teaching point A and the new teaching point B ′, a trajectory along the inclined surface of the work body W1 can be created. Then, when the relay position 104 is reached, the direction of the slope changes, but by checking the change of the contact condition every sampling period, the trajectory is corrected again and the annular part W2 is inserted into the work body W1. Is possible.

  As described above, the robot apparatus 1 according to the first embodiment uses the contact point as the origin when the annular part W2 comes into contact with the work body W1 when the annular part W2 is fitted into the work body W1. A second coordinate system Q is set along the inclination direction of the workpiece body W1. Therefore, the annular part W2 can be moved along the inclination direction of the work body W1. As a result, for example, even when there is a deviation due to the tolerance of the annular part W2 or the workpiece main body W1 or the reproducibility of the posture of the robot arm 20 during operation, the assembly of the annular part W2 to the workpiece main body W1 is failed. Can be reduced. As a result, productivity can be improved.

  Further, in order to calculate the inclination direction according to the force value of the contact point, the contact with the inclined surface of the work body W1 is annulus as in the case where the annular part W2 is assembled to the conical work body W1. Even if it can occur at any position on the inner circumference of the component W2, it is possible to cope with it.

Second Embodiment
Next, a robot apparatus 1A according to a second embodiment of the present invention will be described with reference to FIG. The robot apparatus 1A according to the second embodiment is different from the first embodiment in the operation of the annular component W2 after the relay position 104. Therefore, in the second embodiment, the difference from the first embodiment, that is, the operation of the annular part W2 after the relay position 104 will be mainly described, and the same reference numerals are given to the same configurations as in the first embodiment. The description is omitted.

  FIG. 6 is a diagram illustrating a state in which the robot apparatus 1A according to the second embodiment assembles the ring component W2 to the work body W1.

  In the first embodiment, the change of the contact condition is confirmed up to the insertion position 106, and the trajectory is corrected again at the assembly relay position 104 of the annular part W2. However, when the insertion position 106 of the annular part W2 is known in advance, it is possible to create and operate a trajectory between slopes by correction by instructing only correction up to the relay position 104. Then, the correction | amendment is complete | finished and the track | orbit from the relay position 104 with respect to the conventional 1st coordinate system 118 to the insertion position 106 is produced | generated, and the assembly | attachment to the workpiece | work main body W1 of the annular component W2 is attained. Therefore, the calculation time can be shortened compared to the first embodiment.

<Third Embodiment>
Next, a robot apparatus according to a third embodiment of the present invention will be described with reference to FIGS. The robot apparatus according to the third embodiment is different from the first embodiment in the shapes of the inner member and the outer member. Therefore, in the third embodiment, the difference from the first embodiment, that is, the difference in operation due to the difference in the shape of the inner member and the outer member will be mainly described, and the configuration similar to the first embodiment will be described. Are given the same reference numerals and their description is omitted.

  FIG. 7 is a perspective view showing how the angular ring component W4 is inserted into the work body W3 by the articulated robot 2 according to the third embodiment. FIG. 8 is a top view of parts having different shapes held by the articulated robot 2 according to the third embodiment. FIG. 9 is a top view showing an insertion order of the angular ring component W4 held by the articulated robot 2 according to the third embodiment.

  The work main body W3 according to the third embodiment is an inner member whose outer peripheral surface is a pyramid shape, and the angular ring component W4 is an outer member having an angular annular inner peripheral surface that can be inserted into the work main body W3. Hereinafter, similarly to the first embodiment, an insertion operation of the rectangular ring component W4 into the work body W3 will be described.

  The shape of the square ring component W4 is not limited to the quadrangle shown in FIG. For example, regular polygonal ring parts W5 and W6 as shown in FIGS. 8A and 8B, a rectangular ring part W7 as shown in FIG. 8C, and a polygonal ring as shown in FIG. 8D. It corresponds to various shapes (polygons of triangles or more) such as the part W8.

  As shown in FIG. 7, there is a center axis shift 113 between the work main body W3 and the angular ring component W4, and it cannot be assembled simply by lowering the rectangular ring component W4 to the work main body W3. Therefore, as in the first embodiment, the inclination direction 115 along the outer peripheral surface of the work body W3 at the contact point is calculated from the force value at the time of contact determination, and the angular ring component W4 moves along the inclination direction 115. The tilt direction 115 is set as the second coordinate system of the articulated robot 2 so that it can be performed. Hereinafter, it demonstrates according to the insertion operation | movement of the square ring component W4 of the workpiece | work main body W3. In this embodiment, it is assumed that there is no rotational phase shift with respect to the insertion direction.

  As shown in FIG. 9A, due to the center axis shift 113, the square ring component W <b> 4 comes into contact with the inclined surface 122 of the work body W <b> 3 during the insertion, and a force is applied to the inclined rear surface 123. At this time, it moves to the slope direction 123 by calculation from the reaction force acquisition process (step S4) demonstrated in 1st Embodiment to a track reset process (step S8).

  In the first embodiment, the position of the second coordinate system is created on the circumference of the annular part W1, but in the case of the angular part W4 of the third embodiment, there is no circumference. For this reason, the values of the radii of Equations 4, 5, and 10 used in the calculation are defined as 0, and a second coordinate system centered on the position on the conventional first coordinate system is created.

  When moving in the slope direction 123, as shown in FIG. 9B, the ridgeline 124 of the work body W3 and the inner peripheral angle 125 of the angular ring component W4 come into contact, and a force equal to or greater than the threshold value is generated in the ridgeline direction 126. Since the change of the contact condition is confirmed at every sampling period until the insertion position 106 is reached, recalculation from step S4 to step S8 is performed based on the detected haptic value, and the trajectory is corrected again. Due to the new trajectory defined by recalculation, the angular ring component W4 starts moving in the ridge line direction 126 and moves to the relay position 104 shown in FIG.

  When moved to the relay position 104, as shown in FIG. 9C, the center axis shift 113 between the work main body W3 and the square ring component W4 is canceled and fitted, the contact condition changes, and a force equal to or greater than the threshold value is generated. Since the change of the contact condition is confirmed at every sampling period until the insertion position 106 is reached, recalculation from step S4 to step S8 is performed based on the detected haptic value, and the trajectory is corrected again. Due to the new trajectory defined by recalculation, the angular ring component W4 moves to the insertion position 106 and can be inserted into the workpiece body W3.

  As described above, as shown in the present embodiment, in the present invention, not only an annular shape but also a ring-shaped member can be inserted.

<Fourth embodiment>
Next, a robot apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS. 10 to 12 with reference to FIGS. The robot apparatus according to the fourth embodiment is different from the third embodiment in that there is a rotational phase shift between the work main body W3 and the angular ring component W4. Therefore, in the fourth embodiment, the difference from the third embodiment, that is, the rotation operation executed to eliminate the rotational phase shift between the work body W3 and the angular ring component W4 will be described. The same components as those in the embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 10 is a perspective view showing how the angular ring component W4 is inserted into the work body W3 by the articulated robot 2 according to the fourth embodiment. FIG. 11 is a flowchart showing an insertion operation of the angular ring component W4 into the work body W3 by the articulated robot 2 according to the fourth embodiment.

  In the third embodiment, as shown in FIG. 7, there is no rotational phase shift between the workpiece main body W3 and the square ring component W4, and the phases are matched. Therefore, as shown in FIG. 4, after the new trajectory is created, if it is less than the threshold (Y in step S5), the trajectory is moved to the new trajectory based on the second coordinate system, moved to the relay position 104, and recalculated. When the insertion position 106 was reached (Y in step S9), the insertion was possible. However, in the present embodiment, as shown in FIG. 10, when a rotational phase shift occurs between the workpiece main body W3 and the rectangular ring component W4 and the phases do not match, it does not reach the insertion position 106 and stops halfway. Insertion is impossible. Therefore, in order to assemble the square ring component W4 to the work body W3, it is necessary to adjust the rotational phase shift by performing the rotation operation 127 with the insertion direction as an axis.

  Therefore, a flow as shown in FIG. 11 is added to match the rotational phase shift. First, if it is less than the threshold value (Y in step S5), it is determined whether or not the movement to a new trajectory based on the second coordinate system (new trajectory determination step, step S10). When moving to a new trajectory in the second coordinate system, a rotation operation 127 with the conventional insertion direction as an axis is added to the movement to the new trajectory, that is, a rotation operation 127 with respect to the insertion direction of the first coordinate system is added. (Rotation operation adding step, step S11). Rotation by the rotation operation 127 is performed while moving to a new orbit, thereby adjusting the rotational phase shift and enabling insertion. Hereinafter, the insertion order regarding the fourth embodiment using step S10 and step S11 will be described.

  FIG. 12 is a top view showing an insertion order of the angular ring component W4 held by the articulated robot 2 according to the fourth embodiment.

  As shown in FIG. 12A, the angular ring component W4 contacts the ridgeline 128 of the workpiece body W3 during the insertion due to the center axis shift 113 and the rotational phase shift. At this time, a new trajectory based on the second coordinate system is created by the calculation from the reaction force acquisition step (step S4) to the trajectory resetting step (step S8) described in the third embodiment, and moves in the ridge line direction 129.

  When moving in the ridge line direction 129, the angular ring component W4 comes in contact with the ridge line 130 of the workpiece body W3 on the way, but it becomes less than the threshold (Y in step S5) due to slight contact. Then, since it is moving in the ridge line direction 129, it is determined as a new trajectory based on the second coordinate system (Y in step S10). If it is determined as a new trajectory, the impedance control of the moment with respect to the insertion direction of the first coordinate system is defined and executed in order to perform the rotation operation 127 (step S11). As a result, when a force is generated in the moment direction with respect to the insertion direction, a correction amount by impedance control is added to the direction in which the force generated in the movement of the new track is relaxed, that is, the rotation direction with respect to the insertion direction, and the rotation operation is performed. be able to.

  In the present embodiment, since the angular ring component W4 is in contact with the ridge line 130 of the workpiece body W3, twisting due to the frictional force f occurs during movement in the ridge line direction 129, and the moment in the insertion direction of the first coordinate system is increased. A force Mf is generated. Since the force Mf generated in the moment direction is added to the new trajectory as a correction amount by impedance control, the rotation M 127 rotates in the direction in which the force Mf relaxes while moving in the ridge line direction 129.

  By the rotation operation 127, the rectangular ring component W4 moves in the ridge line direction 129 while rotating. When moved, as shown in FIG. 12B, the ridge line direction 130 of the work body W3 and the inner peripheral angle 131 of the angular ring component W4 are aligned. When the ridge line direction 129 is further moved, the contact condition is changed again, and a force equal to or greater than the threshold value is generated in the ridge line direction 132 where the ridge line of the work body W3 and the inner peripheral angle 131 of the angular ring component W4 are combined. Since the change of the contact condition is confirmed at every sampling period until the insertion position 106 is reached, recalculation from step S4 to step S8 is performed based on the detected haptic value, and the trajectory is corrected again. Due to the new trajectory defined by recalculation, the angular ring component W4 moves in the ridge line direction 132 and moves to the relay position 104.

  When moved to the relay position 104, as shown in FIG. 12C, the center axis shift 113 between the work body W3 and the square ring component W4 is canceled and fitted, the contact condition changes, and a force equal to or greater than the threshold value is generated. Since the change of the contact condition is confirmed at every sampling period until the insertion position 106 is reached, recalculation from step S4 to step S8 is performed based on the detected haptic value, and the trajectory is corrected again. Due to the new trajectory defined by recalculation, the angular ring component W4 moves to the insertion position 106 and can be inserted into the workpiece body W3. As described above, the angular ring component W4 can be inserted into the work main body W3 even when the rotational phase shift occurs.

  As described above, as shown in the present embodiment, in the present invention, it is possible to insert an angular ring-shaped member having a rotational phase shift.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above. 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.

  For example, in 1st and 2nd embodiment, it demonstrated using the insertion operation | movement which makes the end effector 21 hold | grip the annular component W2 as one member, and inserts it in the workpiece | work main body W1 as the other member. However, the present invention is not limited to this. For example, it can also be used when the end effector 21 grips the work body W1 and is inserted into the annular part W2. Similarly, the third and fourth embodiments can also be used when the work body W3 is gripped and inserted into the rectangular ring component W4.

  In the first and second embodiments, when the annular component W2 comes into contact with the work body W1, the second coordinate system Q is set along the inclination direction of the work body W1 with the contact point as the origin. The invention is not limited to this. For example, if the inclination direction is known, the second coordinate system may be set at an arbitrary position different from the contact point. Similarly, in the third and fourth embodiments, any second coordinate system different from the contact point may be set as long as the inclination direction is known.

DESCRIPTION OF SYMBOLS 1, 1A robot apparatus 2 Articulated robot 3, 3A Control apparatus 22 Force sensor 115 Inclination direction 118 1st coordinate system Q 2nd coordinate system W1 Work body (inner member)
W2 Ring part (outer member)

Claims (9)

With articulated robots,
A force sensor capable of detecting a reaction force received by the articulated robot;
An insertion operation is performed in which one of the inner member having an outer peripheral surface and the outer member having an inner peripheral surface into which the inner member can be inserted is inserted and inserted into the other member. In this case, the outer member is relatively moved from the small-diameter portion to the large-diameter portion of the inner member in a designated trajectory created based on the first coordinate system set for the one member held by the articulated robot. The one member gripped by the articulated robot comes into contact with the other member and the force sensor detects the reaction force, and the one member gripped by the articulated robot from the reaction force Is set to the one member gripped by the articulated robot, and the second coordinate system is moved in the second coordinate system to move the second coordinate system along the tilt direction of the outer peripheral surface of the inner member. Grip one member And a control unit in which the moving control articulated robot that, with a,
A robot apparatus characterized by that. The control device performs posture control of the articulated robot so that the one member held by the articulated robot maintains a constant posture when performing the fitting operation.
The robot apparatus according to claim 1. The control device sets the second coordinate system having the contact point when the one member held by the multi-joint robot is in contact with the other member as the origin, as the one member.
The robot apparatus according to claim 1 or 2, wherein An insertion operation for inserting one member of the inner member having the outer peripheral surface and the outer member having the inner peripheral surface into which the inner member can be inserted into the other member, held by the multi-joint robot, is executed. In the control method of the articulated robot,
The control unit moves the relative position of the outer member from the small-diameter portion of the inner member toward the large-diameter portion in a designated trajectory created based on the first coordinate system set for the one member held by the articulated robot. An insertion start step for moving and starting an insertion operation between the inner member and the outer member;
The control unit acquires a reaction force detected by a force sensor capable of detecting a reaction force received by the articulated robot when the one member gripped by the articulated robot comes into contact with the other member. Reaction force acquisition process;
From the reaction force acquired by the control unit, the articulated robot has a second coordinate system in which the inclination direction along the outer peripheral surface of the inner member at the contact point between the inner member and the outer member is a traveling direction. A coordinate system creation step for creating the gripped one member;
A trajectory resetting step in which the control unit resets the trajectory of the articulated robot so that the one member gripped by the articulated robot moves in the second coordinate system;
The control unit controls the articulated robot in accordance with the reset trajectory, and includes a fitting insertion end step for fitting the inner member and the outer member.
A method for controlling an articulated robot. The control unit performs posture control of the articulated robot so that the one member held by the articulated robot maintains a constant posture when the articulated robot performs the insertion operation.
The method for controlling an articulated robot according to claim 4. In the coordinate system creating step, the control unit uses the second coordinate system having the contact point when the one member gripped by the articulated robot contacts the other member as an origin as the one member. Set to
The method for controlling an articulated robot according to claim 4 or 5. A new trajectory determination step for determining whether the control unit is moving the reset trajectory;
A rotation operation adding step of inserting the rotation while adding the rotation around the insertion direction of the specified track created based on the first coordinate system while moving the set track,
The method for controlling an articulated robot according to any one of claims 4 to 6, wherein:   A control program for an articulated robot for causing a computer to execute each step according to any one of claims 4 to 7.   A computer-readable recording medium on which the control program for the articulated robot according to claim 8 is recorded.

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