JP2005199412A - Controlling method and controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controlling method for simply deciding an angular position of a long node part so as to make an operating range of a multi-node robot as wide as possible in controlling the multi-node robot having a plurality of node parts including long node parts. <P>SOLUTION: This method includes a survey step S1 surveying an operating range of an end effector of a multi-node robot at the time of changing angular positions of residual node parts under a condition that a predetermined long node part is fixed when the long node parts are placed at a plurality of angular positions; an extracting step S2 for extracting the angular positions of the long node parts in the operating range satisfying predetermined conditions from each of the operating ranges obtained in the survey step; and a node part control step S3 for controlling the residual node parts to be angularly displaced under a condition that the long node parts are arranged at the angular positions extracted in the extraction step. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control method and a control apparatus for controlling an articulated robot having a plurality of joint parts including redundant joint parts.

  There are various methods for controlling an articulated robot having a plurality of joint parts of seven or more, and typical conventional techniques are described in Patent Document 1 and Patent Document 2. In the control apparatus for the articulated robot of Patent Document 1, the joint angle at which the tip joint of the articulated robot approaches the target position in terms of distance is obtained one by one by the least square method, and the obtained target angle and the current joint angle are calculated. By rotating the joint one axis at a time proportional to the difference between the two, the calculation amount is reduced and the joint at the tip reaches the target position. In the multi-degree-of-freedom manipulator positioning device disclosed in Patent Document 2, a solution curve for designating the entire shape is obtained from the hand position / posture information and the specified value of the entire shape of the manipulator, and the end points of all links are arranged in the shape of the solution curve. The link end point position is calculated as described above, the joint angle between the two links is calculated from the link end point of the adjacent two links and the base side link posture, the hand side link posture is obtained from the joint angle, Then, the joint angle and the link posture are repeatedly calculated sequentially from the root to the hand to obtain the total joint angle, thereby speeding up the calculation of positioning.

  There are also various methods for controlling the articulated robot to avoid an obstacle as described above, and a typical prior art is described in Patent Document 3. In the control device of the manipulator disclosed in Patent Document 3, when moving the handle from the start point to the end point, the displacement of each joint in a state of interfering with an obstacle is obtained in a discrete manner, and each joint is avoided so as to avoid the displacement of each joint. The discrete motions are controlled by joint interpolation or single axis motion of the manipulator.

  A typical prior art for displaying necessary information for teaching the articulated robot as described above is described in Patent Document 4. In the redundant degree-of-freedom robot apparatus disclosed in Patent Document 4, a robot teaching is performed by calculating a region that can be taken by a redundant parameter depending on the current location of an independent variable describing an operation necessary for work, and displaying the result.

  A typical conventional technique for realizing control specifications for each direction in the space of the robot is described in Patent Document 5. In the robot control method of Patent Document 5, specifications of work to be performed by the robot are described using a coordinate system fixed with respect to the work space, and motion control targets in each coordinate axis direction and directions around each coordinate axis are clarified. , Calculating a control performance evaluation index related to work specifications in the direction corresponding to each of the posture states of the robot in the respective directions, and determining the robot posture state having the largest weighted comprehensive evaluation index value as the optimum posture state The work is executed in this state.

Patent Document 6 describes a typical conventional technique for maximizing the reach of the robot arm body with respect to the work target. In the position control method of the industrial robot of Patent Document 6, the position matrix determined by the three basic axes is ^o T _b , the posture matrix taken by the three wrist axes is ^b T _w , and the tool mounting flange matrix is ^w T _f. the end effector matrix of the tool when the ^f T _e, when the position and orientation of the object control points in the Cartesian coordinate system in space is _{^{given, o T CD = o T b}} · b T w · w T f - from the relationship of ^f T _e to control the position of the robot. The possible positions ^o T _b goals ^o T point P _v of the redundant axis direction of the vector V with the origin position of the _CD is a set of the time on the circumference with the origin, from the robot operation origin T ₀ The target ^o T _CD is determined again as ^o T _CD ′ so that the point P _b having the smallest distance becomes an orthogonal component of ^o T _b , the ^o T _CD ′ is inversely transformed, and the derived coordinate system of each joint coordinate system is obtained. The position of each axis is the operation target.

JP 2000-167789 A JP 10-333723 A Japanese Patent Laid-Open No. 11-333780 JP-A-5-337861 JP-A-5-23982 JP 2002-301672 A

  In the position control method described in Patent Document 6, since calculation is performed using many matrices, the time required for matrix calculation becomes enormous, and it is extremely difficult to control the robot quickly, and it must be implemented. Is difficult. Therefore, in controlling an articulated robot having a plurality of joints including redundant joints, it is necessary to simply perform control for widening the operation range of the articulated robot as much as possible.

  It is an object of the present invention to easily determine the angular position of a redundant joint so as to make the operation range of the multi-joint robot as wide as possible in the control of an articulated robot having a plurality of joints including the redundant joint. It is to provide a method and a control device.

The present invention is a control method for controlling an articulated robot having a plurality of joint parts including redundant joint parts,
Investigate the movement range of the free-end part of the articulated robot when the angular position of the remaining joint part is changed with the redundant joint part fixed in advance, when the redundant joint part is at a plurality of angular positions. Survey process to
An extraction step of extracting an angular position of a redundant joint portion that is an operation range that satisfies a predetermined condition among the operation ranges obtained in the investigation step;
And a joint control step for controlling the remaining joint to be angularly displaced in a state where the redundant joint is arranged at the angular position extracted in the extraction step.

  According to the present invention, the operation range that satisfies the predetermined condition includes a position designated in advance.

  Further, according to the present invention, when the angular position of at least one joint portion approaches the limit position of the movable range, the angular position of the joint portion is set to the center of the movable range while holding the free end portion on a predetermined track. When the redundant joint portion is angularly displaced so as to approach the position, and the angular position of each joint portion is in the vicinity of the center position of the movable range, the redundant joint portion is angularly displaced to widen the operating range of the free end portion. The method further includes an auxiliary control step.

Further, the present invention is a control device for controlling an articulated robot having a plurality of joint parts including redundant joint parts,
Investigate the movement range of the free-end part of the articulated robot when the angular position of the remaining joint part is changed with the redundant joint part fixed in advance, when the redundant joint part is at a plurality of angular positions. Investigation means to
An extraction means for extracting an angular position of a redundant joint portion that is an operation range that satisfies a predetermined condition among the operation ranges obtained by the investigation means;
And a joint control unit that controls the remaining joint to be angularly displaced in a state where the redundant joint is arranged at the angular position extracted by the extraction unit.

  According to the present invention, the operation range that satisfies the predetermined condition includes a position designated in advance.

  Further, according to the present invention, when the angular position of at least one joint portion approaches the limit position of the movable range, the angular position of the joint portion is set to the center of the movable range while holding the free end portion on a predetermined track. When the redundant joint portion is angularly displaced so as to approach the position, and the angular position of each joint portion is in the vicinity of the center position of the movable range, the redundant joint portion is angularly displaced to widen the operating range of the free end portion. It further includes auxiliary control means.

  According to the present invention, in the investigation step, the operation range of the free end portion of the multi-joint robot when the angular position of the remaining joint portion is changed in a state where the predetermined redundant joint portion is fixed is determined as the redundant joint portion. Investigate when is at multiple angular positions. In the extraction step, the angular position of the redundant joint portion that is an operation range that satisfies a predetermined condition is extracted from each operation range obtained in the investigation step. In the joint portion control step, control is performed so that the remaining joint portions are angularly displaced while the redundant joint portions are arranged at the angular positions extracted in the extraction step. By controlling the remaining joints to be angularly displaced in a state where the redundant joints are arranged at the angular positions extracted in the extraction step as described above, The range can be operated continuously. Therefore, by extracting the angular position of the redundant joint part for each condition, the free end part of the articulated robot can be reliably and continuously operated within the operation range that satisfies the above condition, and control according to the work can be performed. It can be performed simply.

  Further, according to the present invention, since the motion range that satisfies the predetermined condition includes a predesignated position, the free end portion of the articulated robot can be reliably arranged at the predesignated position.

  According to the invention, in the auxiliary control step, when the angular position of at least one joint portion approaches the limit position of the movable range, the angle of the joint portion is held while holding the free end portion on a predetermined track. The redundant joint is angularly displaced so that the position approaches the center position of the movable range. As a result, the joint portion whose angular position is approaching the limit position of the movable range approaches the central position of the movable range, so that the angular displacement operation can be performed, and the corner for placing the free end portion at a predetermined position. The displacement operation can be reliably performed, and the free end portion can be operated within a predetermined operation range, or can be reliably disposed at a predetermined position. Further, in the auxiliary control step, when the angular position of each joint portion is in the vicinity of the center position of the movable range, the redundant joint portion is angularly displaced in order to widen the operation range of the free end portion. It can operate within a wide operating range.

  Further, according to the present invention, the investigating means determines the operation range of the free end portion of the multi-joint robot when the angle position of the remaining joint portion is changed in a state where the predetermined redundant joint portion is fixed. The case where the part is at a plurality of angular positions is investigated. The extraction means extracts the angular position of the redundant joint portion that is the motion range that satisfies a predetermined condition from the motion ranges obtained by the investigation means. The joint control means controls the remaining joint to be angularly displaced in a state where the redundant joint is arranged at the angular position extracted by the extraction means. By controlling the remaining joint portions to be angularly displaced in a state where the redundant joint portions are arranged at the angular positions extracted by the extraction means in this way, the free end portion of the articulated robot can perform the predetermined operation. The range can be operated continuously. Therefore, by extracting the angular position of the redundant joint part for each condition, the free end part of the articulated robot can be reliably and continuously operated within the operation range that satisfies the above condition, and control according to the work can be performed. It can be performed simply.

  Further, according to the present invention, since the motion range that satisfies the predetermined condition includes a predesignated position, the free end portion of the articulated robot can be reliably arranged at the predesignated position.

  Further, according to the present invention, the auxiliary control means is configured such that when the angular position of at least one joint portion approaches the limit position of the movable range, the angle of the joint portion is held while holding the free end portion on a predetermined track. The redundant joint is angularly displaced so that the position approaches the center position of the movable range. As a result, the joint portion whose angular position is approaching the limit position of the movable range approaches the central position of the movable range, so that the angular displacement operation can be performed, and the corner for placing the free end portion at a predetermined position. The displacement operation can be reliably performed, and the free end portion can be operated within a predetermined operation range, or can be reliably disposed at a predetermined position. Further, the auxiliary control means angularly displaces the redundant joint portion in order to widen the operating range of the free end portion when the angular position of each joint portion is in the vicinity of the center position of the movable range. It can operate within a wide operating range.

  FIG. 1 is a block diagram showing a control device 2 of an articulated robot 1 according to an embodiment of the present invention. The articulated robot 1 is a robot having seven degrees of freedom and having a plurality of degrees of freedom, and in the present embodiment, a plurality of arm bodies 3 to 8 and a plurality of arm bodies rotatably connected to the present embodiment. In a form, it has seven joint parts 9-15. Each arm body 3-8 comprises the arm structure 16 which is each connected and extends linearly.

  Each joint part 9-15 is provided combining the coaxial joint part and the inclination joint part. The coaxial joint shaft connects two adjacent arm bodies so as to be rotatable about a rotation axis that is coaxial with the axis of each arm body. The inclined joint portion connects one of two adjacent arm bodies so as to be conically rotatable about a rotation axis inclined with respect to the axis of each arm body. Specifically, the first joint portion 9, the fifth joint portion 13 and the seventh joint portion 15 are coaxial joint portions, and the second joint portion 10, the third joint portion 11, the fourth joint portion 12 and the sixth joint portion. The joint part 14 is an inclined joint part. Further, in the present invention, the term “rotation” includes not only a rotation of 360 degrees or more around the rotation axis but also a state of angular displacement around the rotation axis by an angle of 360 degrees or less.

  One end portion of the first arm body 3, which is one end portion of the arm structure body 16, is attached to the base 17 fixed to the wall surface 20 or the like by the first joint portion 9 and is coaxial with the axis L 3 of the first arm body 3. It is rotatably connected around one rotation axis L9. One end of the second arm body 4 is inclined by the second joint 10 at a predetermined angle with respect to the axis L3 of the first arm body 3 and the axis L4 of the second arm body 4, 45 degrees in the present embodiment. The second arm 3 is coupled to the other end of the first arm body 3 so as to be rotatable around the second rotation axis L10. One end portion of the third arm body 5 is inclined by the third joint portion 11 at a predetermined angle with respect to the axis L4 of the second arm body 4 and the axis L5 of the third arm body 5, 45 degrees in the present embodiment. The second arm body 4 is connected to the other end of the second arm body 4 so as to be rotatable around the third rotation axis L11. The second rotation axis L10 and the third rotation axis L11 are parallel.

  One end of the fourth arm body 6 is inclined by the fourth joint 12 at a predetermined angle with respect to the axis L5 of the third arm body 5 and the axis L6 of the fourth arm body 6, 45 degrees in this embodiment. The third arm body 5 is coupled to the other end of the third arm body 5 so as to be rotatable around the fourth rotation axis L12. The third rotation axis L11 and the fourth rotation axis L12 are vertical. One end portion of the fifth arm body 7 is rotatable by the fifth joint portion 13 about a fifth rotation axis L13 coaxial with the axis L6 of the fourth arm body 6 and the axis L7 of the fifth arm body 7, It is connected to the other end of the arm body 6.

  One end of the sixth arm body 8, which is the other end of the arm structure 16, has a predetermined angle with respect to the axis L 7 of the fifth arm body 7 and the axis L 8 of the sixth arm body 8 by the sixth joint portion 14. In this embodiment, it is connected to the other end of the fifth arm body 7 so as to be rotatable around the sixth rotation axis L14 inclined at 45 degrees. The end effector 18 serving as the free end of the multi-joint robot 1 is moved around the seventh rotation axis L15 coaxial with the axis L8 of the sixth arm body 8 by the seventh joint 15 at the other end of the sixth arm body 8. Is rotatably connected to. The end effector 18 may be a hand device such as a welding torch or a handling device.

  Each arm body 3-8 incorporates a motor that rotationally drives each arm body 3-8. Each of the arm bodies 3 to 8 is formed with a hollow space through the axis. One or a plurality of wirings are extended and disposed in this hollow space. Each wiring supplies electric power for driving the motor, a rotation command to the motor, electric power to the end effector 18, compressed air, and the like.

  The rotation mechanism that rotates the arm bodies 3 to 8 around the rotation axes L9 to L15 may be the same as the conventional mechanism. As an example of the rotation mechanism, a hollow wave gear mechanism such as a harmonic drive (registered trademark) may be used. The wave gear mechanism includes an input side member and an output side member, and they rotate relatively. The input side member is connected to one of two members (base and arm body) connected by the joint portions 9 to 15, and the output side member is connected to the other of the two members. When rotation from the motor is applied to the input side member, the input side member and the output side member rotate relatively. Thereby, one arm body and the other arm body can be rotated relatively. By providing such a rotation mechanism in each arm body 3-8, two adjacent arm bodies can be rotated relatively.

  As shown in FIG. 1, the spatial coordinate system has two directions perpendicular to the wall surface 20 on which the base 17 of the articulated robot 1 is fixed as an X direction and a Y direction, respectively. The direction away from 20 is the Z direction.

  The control device 2 includes a central processing unit 19. The central processing unit 19 is realized by, for example, a CPU and a memory, and performs calculations necessary for controlling the articulated robot 1 and gives the calculation results to the articulated robot 1 as operation commands.

  FIG. 2 is a flowchart illustrating a procedure of a method for controlling the articulated robot 1 by the central processing unit 19 of the control device 2. The procedure starts at step s0 and proceeds to step s1.

In step s1, which is the investigation process, the central processing unit 19 as the investigation means fixes the angles of the remaining joint portions 10 to 15 in a state where the predetermined redundant joint portion, in the present embodiment, the first joint portion 9 is fixed. The operation range of the end effector 18 of the multi-joint robot 1 when the positions (θ ₂ , θ ₃ , θ ₄ , θ ₅ , θ ₆ , θ ₇ ) are changed, and the first joint unit 9 has a plurality of angular positions θ. _The case of ₁ is investigated, and the process proceeds to step s2.

3 to 10 show the angular positions (θ ₂ , θ ₃ ,...) Of the second to seventh joint parts 10 to 15 as the remaining joint parts in a state where the first joint part 9 is fixed at a certain angular position θ ₁ . θ ₄ , θ ₅ , θ ₆ , θ ₇ ) in the vicinity of the end effector 18 when the motion range of the end effector 18 of the articulated robot 1 is limited to the plane X = 0 when the simulation is performed. It is a figure which shows the operation | movement range of the 6th joint part. 3 is when θ ₁ = 0 degrees, FIG. 4 is when θ ₁ = 45 degrees, FIG. 5 is when θ ₁ = 90 degrees, and FIG. 6 is when θ ₁ = 135. 7 is when θ ₁ = 180 degrees, FIG. 8 is when θ ₁ = 225 degrees, FIG. 9 is when θ ₁ = 270 degrees, and FIG. Is when θ ₁ = 315 degrees.

In the extraction step is a step s2, an extracting means central processing unit 19, among the operating range obtained in step s1, extracting the angular position theta ₁ of the redundant joint to be satisfying operating range predetermined Then, the process proceeds to step s3.

As shown in FIGS. 5 and 9, when the angular position θ ₁ of the first joint portion 9 is 90 degrees and 270 degrees, the angular positions θ shown in other FIGS. 3, 4, 6 to 8, and 10. _It can be seen that the operation range capable of continuous operation is wider than that of ₁ . Also as shown in FIGS. 3 and 7, when the angular position theta ₁ of the first joint portion 9 is 0 degree and 180 degrees, another 4 to 6, the angular position theta ₁ shown in FIGS. 8 to 10 It can be seen that the operating range in which continuous operation is possible is narrow. As shown in FIGS. 3 and 7, when the angular position θ ₁ of the first joint portion 9 is 0 degrees and 180 degrees, the operation range is divided into two. At this time, the end effector 18 of the multi-joint robot 1 is divided. Cannot move directly from one operating range to the other. However, when the angular position theta ₁ of the first joint portion 9 of 90 degrees and 270 degrees, although the lower limit of the Z-direction in the plane X = 0 is about Z = 1000 millimeters, when theta ₁ is 0 degrees and 180 degrees The lower limit of the Z direction in the plane X = 0 can be set to about Z = 200 millimeters.

Thus if the end effector 18 is desired to obtain continuously operable wide operating range may be the angular position theta ₁ of the first joint portion 9, for example 90 degrees and 270 degrees, the end effector 18 Z-axis direction of if you want to place a small position of values, the angular position theta ₁ of the first joint portion 9 may be 0 degrees and 180 degrees. As described above, the angular position θ ₁ of the first joint portion 9 is switched to an arbitrary value based on an operation range including a position where the end effector 18 that is designated in advance is desired, in other words, an operation range that satisfies a predetermined condition. By providing a simple switch in the control device 2, the operator can easily place the end effector 18 at a desired position by switching the switch.

  In step s3, which is a joint control step, the central processing unit 19, which is a joint control means, places the first joint portion 9, which is a redundant joint, at the angular position extracted in step s2, and the remainder. Control is performed so that the joint portions 10 to 15 are angularly displaced, the process proceeds to step s4, and all procedures are terminated. In step s3, the one closer to the current angular position of the first joint part 9 is set out of the extracted angular positions of the first joint part 9.

As described above, when the movement range of the end effector 18 of the articulated robot 1 is limited to the plane of X = 0, the angular position θ ₁ of the first joint portion 9 that is a redundant joint portion is easily derived. be able to. Further, when the movement range of the end effector 18 of the articulated robot 1 is not limited to the plane of X = 0, for example, θ ₁ = {tan ⁻¹ (y / x) +90} instead of 90 degrees and 270 degrees. The degree and θ ₁ = {tan ⁻¹ (y / x) +270} degrees may be set. Here, x is the coordinate of the end effector 18 in the X direction, y is the coordinate of the end effector 18 in the Y direction, and tan ⁻¹ is an arctangent function. Similarly, instead of 0 degrees and 180 degrees, θ ₁ = tan ⁻¹ (y / x) degrees and θ ₁ = {tan ⁻¹ (y / x) +180} degrees may be used. As described above, even when the operation range of the end effector 18 of the multi-joint robot 1 is not limited to the plane of X = 0, the angular position θ ₁ of the first joint portion 9 that is a redundant joint portion can be easily derived. . Therefore, the angular position θ ₁ of the first joint portion 9 that is a redundant joint portion can be easily derived regardless of the operation range.

  As described above, in the present embodiment, the first joint portion 9 is a redundant joint portion, but any one of the first to fourth joint portions 9 to 12 may be a redundant joint portion. With respect to the first to fourth joint portions 9 to 12, the procedure of the flowchart shown in FIG. 2 can be performed. The end effector 18 of the articulated robot 1 performs the predetermined operation by controlling the remaining joint portions to be angularly displaced in a state where the redundant joint portions are arranged at the angular positions extracted in the extraction step. The range can be operated continuously. Therefore, by extracting the angular position of the redundant joint portion for each condition, the end effector 18 of the multi-joint robot 1 can be reliably and continuously operated within the operation range that satisfies the above condition. It can be performed simply. .

Further, in the present embodiment, the angular position θ ₁ to be fixed by the first joint portion 9 as the redundant joint portion is set to 0 degree, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees, Although it is set in increments of 0 to 45 degrees, it is not limited to this. The angular position θ ₁ may be set to 0 degrees, 10 degrees, 20 degrees,..., 340 degrees, 350 degrees, for example, in increments of 0 to 10 degrees, or 0 degrees in increments of 0 to 30 degrees. , 30 degrees, 60 degrees,..., 300 degrees, and 330 degrees may be set.

  In the above control method, when the angular position of at least one joint portion approaches the limit position of the movable range, the angular position of the joint portion is set within the movable range while holding the end effector 18 on a predetermined trajectory. When the redundant joints are angularly displaced so as to approach the central position, and the angular position of each joint is in the vicinity of the central position of the movable range, the auxiliary joint is angularly displaced to widen the operating range of the end effector 18. A control step may be further included.

  Specifically, first, the end effector 18 is held on a predetermined trajectory, and the position and posture of the end effector 18 are maintained, and the displacement direction amount Δθ of the predetermined redundant joint portion is set in the plus direction from the current angular position. The angular position of the remaining joint when the angular displacement is obtained is obtained by inverse transformation.

  Subsequently, the end effector 18 is held on a predetermined trajectory, and with the position and posture of the end effector 18 held, the angular displacement of the redundant joint portion by a predetermined amount of angular displacement Δθ is negatively displaced from the current angular position. The angular position of the remaining joint is obtained by inverse transformation.

  Subsequently, when the angle of the joint axis approaching the limit position of the movable range is angularly displaced in the plus direction from the angle position of the remaining joint part excluding the redundant joint part thus obtained. Compared with the case of angular displacement in the minus direction, the one far from the limit position is adopted.

  In addition, the joint portions 9 to 15 of the multi-joint robot 1 have a predetermined movable range such as −180 degrees or more and +180 degrees or less, and the joint portions cannot be angularly displaced beyond this range. Thus, in order to avoid the angular displacement of each joint portion 9-15 beyond the movable range, when at least one joint portion approaches the limit position of the movable range, the joint portion is moved out of the movable range. By causing the redundant joint portion to be angularly displaced so as to be pulled back to the center position, it is possible to eliminate the problems derived from the movable range of each joint portion.

  As a result, the joint portion whose angular position is approaching the limit position of the movable range approaches the central position of the movable range, and therefore, it is possible to perform an angular displacement operation, and an angle for arranging the end effector 18 at a predetermined position. It is possible to reliably perform the displacement operation, and to move the end effector 18 within a predetermined operation range or to be surely disposed at a predetermined position. Further, in the auxiliary control step, when the angular position of each joint portion is near the center position of the movable range, the redundant joint portion is angularly displaced in order to widen the operation range of the end effector 18, so that the end effector 18 has a wider operation. Can operate within range.

  In the present embodiment, the predetermined trajectory is taught online or offline by the operator according to the work performed by the robot, for example, the welding line at the time of arc welding or the passage trajectory of the load at the time of material handling. Orbit.

It is a block diagram which shows the control apparatus 2 of the articulated robot 1 of one Embodiment of this invention. 4 is a flowchart showing a procedure of a method for controlling the articulated robot 1 by the central processing unit 19 of the control device 2. With the first joint portion 9 fixed at the angular position θ ₁ = 0 °, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 45 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 90 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 135 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 180 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 225 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 270 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range. With the first joint portion 9 fixed at the angular position θ ₁ = 315 degrees, the angular positions (θ ₂ , θ ₃ , θ ₄ , θ _{5) of the second to} seventh joint portions 10 to 15 that are the remaining joint portions. , Θ ₆ , θ ₇ ) when the simulation is performed to change the movement range of the end effector 18 of the articulated robot 1 to the plane X = 0, the sixth joint portion 14 in the vicinity of the end effector 18 It is a figure which shows the operation | movement range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Articulated robot 2 Control apparatus 9-15 Joint part 18 End effector 19 Central processing part

Claims (6)

A control method for controlling an articulated robot having a plurality of joints including redundant joints,
Investigate the movement range of the free-end part of the articulated robot when the angular position of the remaining joint part is changed with the redundant joint part fixed in advance, when the redundant joint part is at a plurality of angular positions. Survey process to
An extraction step of extracting an angular position of a redundant joint portion that is an operation range that satisfies a predetermined condition among the operation ranges obtained in the investigation step;
And a joint portion control step for controlling the remaining joint portions to be angularly displaced in a state where the redundant joint portions are arranged at the angular positions extracted in the extraction step.   The control method according to claim 1, wherein the operation range that satisfies the predetermined condition includes a position designated in advance.   When the angular position of at least one joint portion approaches the limit position of the movable range, the angular position of the joint portion is brought closer to the central position of the movable range while holding the free end portion on a predetermined track. An auxiliary control step of angularly displacing the redundant joint portion in order to widen the operating range of the free end portion when the redundant joint portion is angularly displaced and the angular position of each joint portion is in the vicinity of the center position of the movable range; The control method according to claim 1, further comprising: A control device for controlling an articulated robot having a plurality of joint parts including redundant joint parts,
Investigate the movement range of the free-end part of the articulated robot when the angular position of the remaining joint part is changed with the redundant joint part fixed in advance, when the redundant joint part is at a plurality of angular positions. Investigation means to
An extraction means for extracting an angular position of a redundant joint portion that is an operation range that satisfies a predetermined condition among the operation ranges obtained by the investigation means;
A control apparatus comprising: joint control means for controlling the remaining joint portions to be angularly displaced in a state where the redundant joint portions are arranged at the angular positions extracted by the extraction means.   The control apparatus according to claim 4, wherein the operation range that satisfies the predetermined condition includes a position designated in advance.   When the angular position of at least one joint portion approaches the limit position of the movable range, the angular position of the joint portion is brought closer to the central position of the movable range while holding the free end portion on a predetermined track. Auxiliary control means for angularly displacing the redundant joint portion in order to widen the operating range of the free end portion when the redundant joint portion is angularly displaced and the angular position of each joint portion is in the vicinity of the center position of the movable range. The control device according to claim 4, comprising: a control device.

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