JP2013163230A - Robot controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that an error has occurred since a traditional robot controller cannot reach a target position at a center position of a carried object of a second hand member in the case the target position at the center position of the carried object of the second hand member is not on a retraction line.SOLUTION: A second hand member 30 is surely moved to a target position by conducting processing for obtaining a carried object center position Pat starting and a target carried object center position Pof a carried object center position P, and a rotation center position Wat starting and a target rotation center position Wof a rotation center position W of a second hand member 39, and processing for setting a passing position Pat a position between the carried object center position Pat starting and the target carried object center position Pof the carried object center position P of the second hand member 30 based on the carried object center position Pat starting and the target carried object center position Pand the rotation center position Wat starting and the target rotation center position W.

Description

  The present invention relates to a robot control apparatus, and more particularly to a robot control apparatus that controls an industrial robot.

  A robot control device that controls a horizontal articulated robot that loads and unloads objects to be transported such as a semiconductor wafer and a liquid crystal substrate from a storage body such as a cassette is disclosed (for example, see Patent Document 1). The robot is controlled so that the hand member moves linearly toward the storage body, holds the object to be transported by the hand member, and carries the object to be transported in and out of the storage body. Are provided with two hand members at the same one end.

  In a conventional robot control apparatus, for example, when carrying out a straight movement of one hand member (first hand member) when carrying an object to be conveyed from a cassette, the other hand member (second hand member) interferes with the cassette. The evacuation operation is started so that it does not occur. That is, the center position of the object to be conveyed of the second hand member is prevented from moving to the cassette side with respect to the predetermined retreat line. The position of the retreat line is determined in advance based on information on the positions of the cassette and other devices (such as a processing device) existing in the traveling direction of the first hand member. In the retreat operation, the second hand member is moved so that the center position of the object to be conveyed of the second hand member moves toward the target position taught on the retreat line and moves along the retreat line after reaching the retreat line. The rotation is controlled.

JP 2009-136981 A

  As described above, in the conventional robot control device, during the rectilinear movement of the first hand member, the center position of the object to be conveyed of the second hand member is directed to the target position taught on the retreat line, and after reaching the retreat line, It is moved along the retreat line. However, when the target position of the center position of the object to be conveyed of the second hand member is taught at a position deviated from the retract line for some reason, the second hand member is moved along the retract line after reaching the retract line. When the robot cannot reach the target position, an error occurs and the entire robot may stop.

  Therefore, in view of the problem, the present invention can surely move the other hand member to the target position during the retraction operation of the other hand member during the rectilinear operation of one hand member, and reliably perform the retraction operation. It is an object of the present invention to provide a robot control apparatus that can perform the operation.

  In other words, the invention according to claim 1 is a robot control device for controlling a robot for carrying an object in and out of a storage body, and one end of the robot is rotatable to a base member via an arm drive shaft. An arm mechanism supported by the first hand member that can be supported by the other end of the arm mechanism via a first hand shaft and can hold the object to be conveyed; and the other end of the arm mechanism, A second hand member supported via a second hand shaft disposed coaxially with the first hand shaft and capable of holding the object to be transported, wherein the robot control device comprises the first hand When the member is linearly moved so as to move forward or backward, the current position and the target position of the conveyed object center position and the current position and the target position of the rotation center position of the second hand member are acquired. And a current position and a target position of the object center position of the second hand member and a current position and a target position of the rotation center position based on the current position and the target position of the second hand member; And a process of setting a via position between the target position and the target position.

  In the invention according to claim 2, the robot control device calculates a midpoint based on the current position and the target position of the center position of the object to be conveyed of the second hand member, and determines the rotation center position from the midpoint. A process is performed in which a perpendicular line is drawn with respect to a straight line connecting the current position and the target position, and a point separated from the intersection of the straight line and the perpendicular line by the hand length of the second hand member in the perpendicular direction is set as a via position. .

  As effects of the present invention, the following effects can be obtained.

  The second hand member according to claim 1, wherein the transported object center position moves from the current position to the target position via the transit position, so that the transported object center position moves from the current position to the target position. Can always move to the target position, and the retraction operation can be performed reliably.

  In addition to the effect of the invention of claim 1, the invention described in claim 2 moves the center position of the transported object from the current position to the target position via the relay position, so that the center position of the transported object is the current position. When moving from the center position to the target position, the distance between the rotation center position and the conveyed product center position can be moved while avoiding a position where the distance is longer than the hand length of the second hand member. The two-hand member can always move to the target position, and the retracting operation can be performed reliably. In the case where the target position is taught at a position deviated from the retreat line, the simplest control for causing the second hand member to reach the target position is the target position taught at the position deviated from the retreat line and the current position. It is conceivable to simply interpolate between. However, if the target position is taught to be shifted from the retreat line to the rotation center position side of the second hand member, a trajectory that draws a large arc from the retreat line to the cassette side is generated as the trajectory to the target position. In this case, interference may occur. Therefore, in the invention of claim 2, a via position is provided closer to the rotation center position than the retreat line, and interference is suppressed by passing this via position.

1 is a block diagram showing a schematic configuration of a robot control system to which a robot control apparatus according to an embodiment of the present invention is applied. The top view which shows operation | movement when a robot carries a semiconductor wafer out of a predetermined | prescribed cassette. The flowchart figure which shows operation | movement control of a 2nd hand member. (A) Schematic plan view showing the trajectory when the second hand member is retracted (b) Schematic plan view showing the trajectory when the second hand member is retracted when passing the via position. FIG. 6 is a schematic plan view showing the relationship between the rotation center position of the second hand member, a circle centering on the rotation center position and having a hand length as a radius, and a straight line passing through the trajectory of the object center position of the second hand member. The schematic plan view showing the rotation angle of the second hand member.

Next, embodiments of the invention will be described.
First, a robot control system 10 according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the robot control system 10 includes a horizontal articulated robot 11, a robot control device 12 that controls the operation of the robot 11, and a teaching box 13 that teaches the operation of the robot 11. . The robot control device 12 includes a servo amplifier 15 that drives a servo motor attached to the robot 11, and a control unit 14 that gives an instruction to the servo amplifier 15 to control the operation and posture of the robot 11.

  The robot 11 includes a base member 16 installed at a predetermined place, and an arm mechanism 17 that is rotatably supported by the base member 16. The arm mechanism 17 has a lower arm member 19 whose one end is rotatably supported by a base member 16 via a first shaft 18 as an arm drive shaft, and a second end which is a second end on the other end of the lower arm member 19. And an upper arm member 21 that is rotatably supported via a shaft 20.

  The robot 11 includes a first hand member 28 whose end is rotatably supported by the other end of the upper arm member 21 via a first hand shaft 27, and an end that is the other end of the upper arm member 21. The second hand member 30 is rotatably supported via the second hand shaft 29. The first hand shaft 27 and the second hand shaft 29 have the second hand shaft 29 coaxially installed on the upper side of the first hand shaft 27, and the respective shaft centers coincide in plan view. That is, the robot 11 includes two hand members that are supported by the upper arm member 21 and have the same rotation center. The lower arm member 19 is disposed above the base member 16, the upper arm member 21 is disposed above the lower arm member 19, the first hand member 28 is disposed above the upper arm member 21, and the first hand member 28 is disposed. The second hand member 30 is disposed on the upper side of the first hand member. The lower arm member 19, the upper arm member 21, the first hand member 28, and the second hand member 30 are each rotatable in the horizontal direction.

  The first hand member 28 and the second hand member 30 that can hold the object to be conveyed are formed in an elongated U shape having the same shape in plan view, and the bent portion side becomes a base point (the rotation center). The first hand shaft 27 and the second hand shaft 29 are arranged. Each of the first hand member 28 and the second hand member 30 is provided with holding means such as vacuum suction (not shown), and the object to be conveyed is placed on the upper surfaces of the first hand member 28 and the second hand member 30 by the holding means. Fixed. When the first hand member 28 is fixed and the second hand member 30 is rotated about the second hand shaft 29, they overlap and the first hand member 28 is below the second hand member 30 in plan view. It is configured to be hidden on the side. The lower arm member 19 and the upper arm member 21 are formed in an elongated flat plate shape, and the length of each of the lower arm member 19 and the upper arm member 21 is fixed when the lower arm member 19 is fixed and the upper arm member 21 is rotated about the second shaft 20. The length is set such that the first shaft 18 and the second shaft 20 overlap. The base member 16 is formed in a quadrangular prism shape whose longitudinal direction is the vertical direction, and is configured to accommodate a first shaft 18 formed in a cylindrical shape whose longitudinal direction is the vertical direction.

  The first shaft 18, the second shaft 20, the first hand shaft 27, and the second hand shaft 29 are drive shafts, and servo motors (not shown) are installed on the respective drive shafts. The first shaft 18 has a servo motor for rotating the lower arm member 19, the second shaft 20 has a servo motor for rotating the upper arm member 21, and the first hand shaft 27 has a first hand member 28. The second hand shaft 29 is provided with a servo motor for rotating the second hand member 30. The output shafts of the servo motors and the lower arm member 19, the upper arm member 21, the first hand member 28, and the second hand member 30 are connected to each other so that the lower arm member 19, the upper arm member 21, and the first arm member 21 are connected to each other. The hand member 28 and the second hand member 30 can be independently rotated. Encoders (not shown), which are operation amount detection means for detecting the rotation speed and the rotation amount of each rotation shaft of the servomotor, are installed on each rotation shaft of the servomotor (not shown). The rotation amount of the lower arm member 19, the upper arm member 21, the first hand member 28, and the second hand member 30 is detected by the operation amount detection means. Furthermore, a servo motor or a cylinder (not shown) for raising and lowering the first shaft 18 in the vertical direction is installed in the first member 18 inside the base member 16. The elevation distance of the first shaft 18 is detected by an encoder (not shown) which is a height detection means.

  Since the base member 16 is installed at a predetermined position, the first shaft 18 does not move, and the first hand member 28 and the second hand member 30 move within a predetermined range in the horizontal direction with the first shaft 18 as a base point. It will be. Further, when the first shaft 18 moves up and down, the lower arm member 19, the upper arm member 21, the first hand member 28 and the second hand member 30 which are connected to each other move up and down integrally. In this way, the robot 11 operates to convey the object to be conveyed within a predetermined range.

  The servo amplifier 15 supplies power to the servo motors installed on the first shaft 18, the second shaft 20, the first hand shaft 27 and the second hand shaft 29 based on a command signal from the control unit 14. Drive the servo motor. In addition, detection information such as the rotation angle from the encoder is fed back to the servo amplifier 15, and the servo amplifier 15 drives the servo motor so as to eliminate the difference between the command signal from the control unit 14 and the feedback signal from the encoder. Control. This control is performed by PI control, PID control, or the like, but is not limited thereto.

  The teaching box 13 is installed in the vicinity of the robot 11 and includes a switch for operating the robot 11. Using the teaching box 13, teaching points including the position and posture of the robot 11 are taught.

  The control unit 14 is connected to the servo amplifier 15 and the teaching box 13 to control the entire robot control system 10. The control unit 14 controls the operation and posture of the robot 11 by driving a servo motor set for each drive axis by sending a command signal to the servo amplifier 15 and a function for storing the contents input by the teaching box 13. And a function of acquiring and calculating information detected by an encoder such as a rotation angle of a rotation shaft of a servo motor installed on each drive shaft through a servo amplifier 15. The control unit 14 controls the operation of the robot 11 so that the robot 11 moves between teaching points taught by the teaching box 13.

  Next, the operation of the robot 11 controlled by the control unit 14 will be described.

  FIG. 2 is a plan view showing an operation when the robot shown in FIG. 1 carries out the semiconductor wafer 23 which is an example of the transferred object from a predetermined cassette.

  The robot 11 is installed at an arbitrary distance from the cassette 24 which is a storage body in which the semiconductor wafer 23 is stored. The robot 11 carries in and out the semiconductor wafer 23 from the cassette 24 and transports the semiconductor wafer 23 to a processing apparatus or the like (not shown). From (a) to (c) of FIG. 2, the robot 11 having two hand members holds the semiconductor wafer 23 on the second hand member 30, and the predetermined cassette 24 is used by the first hand member 28. A series of operations to carry in the semiconductor wafer 23 is shown.

  As shown in FIG. 2A, the semiconductor wafer 23 is held on the first hand member 28 and the second hand member 30. The second hand member 30 is stopped in a state of being rotated counterclockwise in plan view about the second hand shaft 29 from the direction in which the first hand member 28 is directed (the direction of the cassette 24). As shown in FIG. 2A, the retreat line L is set, and the second hand member 30 is on the retreat line L. In the present embodiment, the object center position P, which is the center position of the semiconductor wafer 23 when the semiconductor wafer 23 is held by the second hand member 30, is on the retreat line L. The position of the evacuation line L is determined in advance based on information on the positions of the cassette 24 and other devices (such as processing devices) existing in the traveling direction of the first hand member 28. In the present embodiment, the direction is a direction orthogonal to the traveling direction of the first hand member 28.

As shown in FIG. 2B, when the first hand member 28 is manually linearly moved toward the cassette 24, the second hand member 30 is moved to the second hand member 30 or the second hand member 30. In order to avoid the held semiconductor wafer 23 from interfering with the cassette 24, the semiconductor wafer 23 is further rotated counterclockwise in plan view about the second hand shaft 29. At this time, the second hand member 30 rotates so that the second hand member 30 is on the retreat line L. In the present embodiment, the second hand member 30 rotates so that the conveyed object center position P is on the retreat line L.
Then, when reaching the position shown in FIG. 2C where the semiconductor wafer 23 has been carried into the cassette 24 from the first hand member 28, the first hand member 28 and the second hand member 30 are simultaneously stopped.

  Next, the control for calculating the trajectory of the center position of the conveyed object of the second hand member 30 to be retracted. This will be described with reference to FIG.

First, based on information such as the rotation angle of the rotation shaft of each servo motor acquired through the servo amplifier 15, the control unit 14 moves the first hand member 28 at the time of linear movement. the current position of the conveyed object center position P (hereinafter, beginning transported object center position P _s that) the current position of and turning center position W (hereinafter, referred to as start turning center position W _s) to obtain information ( Step S10).
The information on the starting transported object center position P _s and the starting rotation center position W _s is acquired as information defined by the Cartesian coordinate system.

  Next, the control unit 14 determines the traveling direction and the target of the first hand member 28 based on the input contents from the teaching box 13 regarding the traveling direction and the target position of the first hand member 28 stored in the control unit 14. Information on the position is acquired (step S20).

Next, the control unit 14 conveys the second hand member 30 at the time when the straight movement to the target position of the first hand member 28 is completed based on the information on the traveling direction and the target position of the first hand member 28. target position of the object center position P (hereinafter, goal transported object center position P _e) and a target position of the rotation center position W (hereinafter, referred to as the target turning center position W _e) is calculated (step S30).

Information on the target conveyed object center position P _e and the target rotation center position W _e is acquired as information defined by the Cartesian coordinate system.
Moreover, the control part 14 sets the evacuation line L (step S40). Specifically, it has the same vector with a predetermined retracted line L (see FIG. 2), sets a new evacuation line L1 including the target object to be conveyed center position P _e. Thereafter, the trajectory is calculated so that the second hand member 30 does not move to the cassette 24 side beyond the new retreat line L1.

Next, the control unit 14 calculates a midpoint P _m using a start transported object center position P _s and the target object to be conveyed center position P _e (step S50).
Next, the control unit 14 calculates the first rotation center position W _m (step S60). The first rotation center position W _m draws a straight line from the middle point P _{m in} a direction parallel to the retreat line L1, and is a straight line parallel to the traveling direction passing through the rotation center position W _s at the start of the second hand member 30. Is the intersection of

Next, the control unit 14, beginning the rotation center position W _s, to determine the positional relationship of the first turning center position W _m, and the target turning center position W _e (step S70).
Specifically, it is determined whether or not the first rotation center position W _m is closer to the target rotation center position W _e than the start rotation center position W _s .

If it is determined in step S70 that the first rotation center position W _m is not closer to the target rotation center position W _e than the start rotation center position W _s , that is, start time rotation. When the movement center position W _s , the target rotation center position W _e , and the first rotation center position W _m are arranged in this order, the control unit 14 starts the transport object center position P _s at the start and the target transport object center. calculating a line segment connecting the position P _e as a trajectory of the conveyed object center position P of the second handling member 30 (step S80).

For example, as shown in FIG. 4A, when the start rotation center position W _s , the target rotation center position W _e , and the first rotation center position W _m are arranged in this order, the transferred object at the start time on a straight line connecting the center position P _s and the target object to be conveyed center position P _e, since the second hand member 30 is not present physically impossible position to move, the solid thin line in FIG. 4 (a) as shown in, as a trajectory of the conveyed object center position P of the straight line connecting the transported object center position P _s and the target object to be conveyed center position P _e at the start.

If it is determined in step S70 that the first rotation center position W _m is closer to the target rotation center position W _e than the start rotation center position W _s , that is, the start rotation time. When the movement center position W _s , the first rotation center position W _m , and the target rotation center position W _e are arranged in this order, the control unit 14 calculates a via position P _m2 (step S90).
The via position P _m2 is on a straight line connecting the middle point P _m and the first rotation center position W _m and is set at a position separated from the rotation center position W _m by the hand length r of the second hand member 30. Is done.

Next, the control unit 14, a line segment connecting the through position P _{m @ 2} and the conveyed object center position P _s, and the line segment connecting the through position P _{m @ 2} and a transported object center position P _e second hand member It is calculated as a trajectory of the center position P of the 30 transported objects (step S100).

For example, as shown in FIG. 4B, when the start rotation center position W _s , the first rotation center position W _m , and the target rotation center position W _e are arranged in this order, the transferred object at the start time on a straight line connecting the center position P _s and the target object to be conveyed center position P _e, the second handling member 30 may be physically impossible position at which the midpoint P _m is present to move. Therefore, as shown by the solid line thin line (b) in FIG. 4, a line connecting the through position P _{m @ 2} and the conveyed object center position P _s, and a through position P _{m @ 2} and a transported object center position P _e A line segment to be connected is set as a trajectory of the object center position P of the second hand member 30.

Next, a method of calculating the rotation angle θ of the second hand member 30 when the transported object center position P is at an arbitrary position on the track will be described with reference to FIGS. 5 and 6.
The rotation angle θ is an angle that rotates counterclockwise about the rotation center from the position of the second hand member at the start of rotation (see FIG. 6).

Here, the coordinates in the arbitrary XY coordinate system of the conveyed object center position P at a certain point in time (x _P , y _P ), and the coordinates in the arbitrary XY coordinate system of the conveyed object central position P _s at the start time. (x _Ps, y _Ps), coordinates of an arbitrary XY coordinate system of the target object to be conveyed center position _{P e (x Pe, y Pe} ), the coordinates of an arbitrary XY coordinate system of the midpoint P _m (x _Pm , y _Pm ), coordinates of the via position P _{m2 in} an arbitrary XY coordinate system (x _Pm2 , y _Pm2 ), coordinates of the rotation center position W _{s in} an arbitrary XY coordinate system (x _Ws , y _Ws ), The coordinates of the rotation center position W _{e in} an arbitrary XY coordinate system (x _We , y _We ), the coordinates of the rotation center position W _{m in} an arbitrary XY coordinate system (x _Wm , y _Wm ), x component of the parallel vector a and the retracted lines L1, defines the y component and (a _x, a _y).

The rotation angle θ of the second handling member 30 when the rotation center position W of the second handling member 30 at a certain point in time is in between the turning center position W _s and W _e is determined as follows.

First, the line segment P _s P _e, the line segment P _s P _{m @ 2} or a linear equation of the line segment P _{m @ 2} P _e can be obtained respectively the following formulas.

Here, a ₃ , b ₃ and c ₃ are arbitrary constants. Following description concerns a case where there is a line segment P _s P _e transported object center position P on. Incidentally, the line segment P _s P _{m @ 2,} or in even less the same way when there is a line segment P _{m @ 2} P _e transported object on the central position P obtains the rotational angle theta.

Segment P _s P _e of the direction vector e (e _x, e _y), and the normal vector v (v _x .v _y) is calculated by the following equation.

Next, determine the coordinates of the intersection point P _h from the rotation center position W and the straight line passing through the line segment P _s perpendicular drawn to a straight line passing through P _e and the line segment _{P s P e (x h,} y h). Here, the coordinates of the rotation center position W are (x _W , y _W ).

Since the intersection point P _h is on a straight line, the following expression is established.

Therefore, as shown in FIG. 5, the distance k from W to P _h is expressed by the following equation.

Here, as shown in FIG. 5, when the distance in the radial hand length arc and the intersection of the straight line (3) of r around the W from P _h and s, the distance s is expressed by the following equation.

However, there is no solution when k> r.
The two intersections obtained from the above are expressed by the following equations.

When the angle at which the second hand member 30 is rotated counterclockwise from a direction parallel to the X direction in an arbitrary coordinate system is the hand posture, (x ₁ , y ₁ ) (x ₂ , y ₂ ) is The postures Φ ₁ and Φ ₂ of the second hand member 30 when the second hand member 30 is set to the conveyed object center position P are expressed by the following equations.

A posture close to the previous interpolation point from these postures is defined as a solution Φ.
As shown in FIG. 6, the rotation angle θ of the second hand member 30 is expressed by the following equation.

Here, the rotation angle θ of the second hand member 30 is an outer angle formed by the upper arm member 21 and the second hand member 30, and in the present embodiment, the counterclockwise direction in plan view (θ in FIG. 6). (Arrow direction) is positive.
In addition, Φ is an inner angle of an angle formed by the X axis passing through the second hand shaft 29 and the second hand member 30, and in the present embodiment, a counterclockwise direction in plan view (an arrow direction of Φ in FIG. 6). Positive.
Further, θ1 is an inner angle of an angle formed by the X axis passing through the first axis 18 and the lower arm member 19, and in this embodiment, the counterclockwise direction in plan view (the arrow direction of θ1 in FIG. 6) is positive. To do.
In addition, θ2 is an outer angle formed by the lower arm member 19 and the upper arm member 21, and in this embodiment, the clockwise direction in plan view (the arrow direction of θ2 in FIG. 6) is positive.

By determining the manner theta, transported object center position P of the second handling member 30 is reliably through the orbit to reach the target object to be conveyed center position P _e.

As described above, the robot control apparatus 12 controls the robot 11 that carries the semiconductor wafer 23 in and out of the cassette 24, and the robot 11 is rotatable at one end to the base member 16 via the first shaft 18. An arm mechanism 17 to be supported, a first hand member 28 that can be supported by the other end of the arm mechanism 17 via the first hand shaft 27 and can hold the semiconductor wafer 23, and an arm mechanism 17 at the other end A second hand member 30 supported by a second hand shaft 29 disposed coaxially with the first hand shaft 27 and capable of holding the semiconductor wafer 23. The robot controller 12 includes: in case of linear movement to advance or retract the handling member 28, at the start of the transported object transported object center position P of the second handling member 39 the center position P _s及Goals and transported object center position P _e and the process of acquiring the start rotation center position W _s and the target turning center position W _e of the rotation center position W, transported object center position P of the second handling member 30 beginning on the basis of the conveyed object center position P _s and start turning center position of the target object to be conveyed center position P _e and the rotation center position W W _s and the target turning center position W _e, the second handling member 30 , a process of setting a via position P _{m @ 2} between the start conveyed object center position P _s and the target object to be conveyed center position P _e transported object center position P of and performs.
With this configuration, by moving to the transferred object center position P via the through position P _{m @ 2} from the start time of the transported object center position P _s target object to be conveyed center position P _e, transferred object when the center position P moves from the start conveyed object center position P _s to the target object to be conveyed center position P _e, for moving it can be moved to avoid physically impossible position, can second hand member 30 moves always to the target object to be conveyed center position P _e, can be reliably saving operation.

Further, the robot controller 12 calculates a midpoint P _m based on the second start transported object transported object center position P of the hand member 30 the central position P _s and the target object to be conveyed center position P _e, from the midpoint P _m, a vertical line with respect to a straight line connecting the and start turning center position W _s and the target turning center position W _e of the rotation center position W, the second hand from the intersection of the said straight line and the perpendicular A process of setting the point separated in the perpendicular direction by the hand length r of the member 30 as the via position P _m2 is performed.
With this configuration, by moving to the transferred object center position P via the through position P _{m @ 2} from the start time of the transported object center position P _s target object to be conveyed center position P _e, transferred object when the center position P is started when moving from the conveyed object center position P _s to the target object to be conveyed center position P _e, the distance the second handling member 30 between the rotation center position W and conveyed center position P Therefore, the second hand member 30 can always move to the target position and can be reliably retracted.

  In the embodiment of the present invention, the first hand member 28, the second hand member 30, and the arm mechanism 17 are rotated in the horizontal direction. However, it is not always necessary to configure in this manner, and in other plane directions. You may rotate. For example, the present invention may be applied to a vertical articulated robot.

  Further, in the embodiment of the present invention, it is composed of two arm members, but if the two hand members are supported by one end of one arm member via each of the drive shafts installed coaxially. , May be composed of three or more.

  In the embodiment of the present invention, the two arm members are configured to have the same length, but may be configured to have different lengths.

  Further, in the embodiment of the present invention, the arm mechanism 17 is supported by the base member 16, but may be supported by a member having another configuration, and the first shaft 18 does not move up and down. Also good.

  In the embodiment of the present invention, the first hand member 28 and the second hand member 30 are configured to hold the object to be conveyed by vacuum suction or the like, but if the object to be conveyed can be held, You may comprise the 1st hand member 28 and the 2nd hand member 30 so that a conveyed product may be hold | maintained by methods, such as pinching.

  In the embodiment of the present invention, the retract line L1 is set in a direction orthogonal to the traveling direction of the first hand member 28, but is not limited thereto. The traveling direction and the retreat line may intersect at an acute angle.

DESCRIPTION OF SYMBOLS 11 Robot 12 Robot control apparatus 16 Base member 17 Arm mechanism 18 1st axis | shaft (arm drive axis)
19 Lower arm member 20 Second shaft 21 Upper arm member 23 Semiconductor wafer (conveyed object)
24 cassette
27 through first hand shaft 28 first hand member 29 second hand shaft 30 second hand member P conveyed object center position P _s at the start conveyed object center position P _e target object to be conveyed center position P _m midpoint P _{m @ 2} position W rotation center position W _s start turning center position W _e target turning center position

Claims (2)

A robot control device that controls a robot that carries a transported object in and out of a storage body,
The robot has an arm mechanism whose one end is rotatably supported by a base member via an arm drive shaft;
A first hand member that is supported on the other end of the arm mechanism via a first hand shaft and can hold the object to be transported, and is coaxial with the first hand shaft at the other end of the arm mechanism. A second hand member that is supported via the arranged second hand shaft and can hold the object to be conveyed;
In the case where the robot control device linearly moves the first hand member to move forward or backward,
A process of acquiring a current position and a target position of the conveyed object center position of the second hand member and a current position and a target position of the rotation center position;
Based on the current position and target position of the transported object center position of the second hand member and the current position and target position of the rotation center position, the current position and the target position of the transported object center position of the second hand member And a process for setting a via position between the robot control apparatus and the robot control apparatus. The robot control device calculates a midpoint based on a current position and a target position of a transported object center position of the second hand member, and a straight line connecting the current position and the target position of the rotation center position from the midpoint. 2. The process according to claim 1, wherein a perpendicular line is drawn and a point that is separated from the intersection of the straight line and the perpendicular line by the hand length of the second hand member in the perpendicular direction is set as a via position. Robot control device.

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