JP4974859B2 - Robot controller - Google Patents

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 transports an object to be transported such as a semiconductor wafer or a liquid crystal substrate from a cassette to a processing apparatus is disclosed (for example, see Patent Document 1). The robot includes a hand member that holds an object to be transported, an upper arm member that supports a hand member via a drive shaft at one end, and a lower portion that supports the other end of the upper arm member via a drive shaft at one end. An arm member and a base member that supports the other end of the lower arm via a drive shaft are provided. The robot may be controlled so that a plurality of teaching points are specified and the specified teaching points are operated by joint interpolation. When a transported object is transported between an arbitrary start point and an arbitrary target point, the robot is designated such that the start point and the target point are taught points, and the transported object moves from the start point to the target point. In addition, the speed of each drive axis is controlled to control the operation of the robot. At this time, the path connecting the start point and the target point and the posture of the robot between the start point and the target point are free. The drive shaft that supports the hand member and the trajectory of the drive shaft that supports the upper arm member are not controlled. Since the speed is controlled for each drive shaft, the motion ratio of the motion amount of each drive shaft in a predetermined time is different, and the trajectory changes depending on the transport speed for transporting the object to be transported. Therefore, when the robot is installed in a narrow space such as between the cassette and the processing apparatus, the starting point is set so that the object to be transported, the hand member, and the upper arm member do not interfere with obstacles such as the cassette and the processing apparatus. A plurality of teaching points are designated as relay points between the target point and the target point. Further, when a singular point exists between the start point and the target point, a plurality of teaching points are set around the singular point in order to avoid the robot passing through the singular point. A singular point is a point at which control becomes impossible and the robot cannot move in a specific direction. When trying to pass a singular point, the rotational speeds of the hand member, the upper arm member, and the lower arm member change rapidly.
JP 2005-246547 A

  In the conventional robot control apparatus as described above, when the transport speed of the object to be transported changes, the trajectory of each drive shaft changes, and the trajectory of the hand member or arm changes. Further, the singular point or the vicinity of the singular point cannot be passed through the robot at a desired transfer speed. Therefore, when the robot is installed in a narrow place where it is necessary to avoid interference with an obstacle and a singular point exists between the start point and the target point, multiple robots are required between the start point and the target point. A teaching point is specified. For this reason, the conveyance speed of the object to be conveyed becomes slow, and it takes time to start up the apparatus.

  The present invention has been made to solve the above-described problems, and the trajectory of the hand member and the arm is constant regardless of the conveyance speed, and the teaching point is designated between the singular point and the starting point or the target point. It is an object of the present invention to provide a robot control device that operates a robot so that a singular point passes from a start point to a target point without increasing the speed, thereby improving the transport speed and shortening the startup time of the device.

  In order to achieve the above object, an invention according to claim 1 is a robot control device for controlling a robot so as to transport a transported object by moving from a starting point across a singular point to a target point. The robot has a plurality of drive shafts and holds a transported object, and an arm mechanism that rotatably supports the hand member at one end via one of the drive shafts, A base member that rotatably supports the other end of the arm mechanism via one of the drive shafts, and the robot operation from the starting point to the singular point and the robot from the singular point to the target point. Dividing into movements, and for each of the divisions, a difference calculating means for calculating a difference in the amount of movement of each of the drive axes at the starting point or the target point with respect to the singular point of the robot, and one of the drive axes as a reference axis , Other drive shafts against the difference of its reference axis Ratio calculating means for calculating the difference operation ratio and operation means for operating the robot from the starting point or the target point to the singular point by driving each of the drive axes at the calculated operation ratio. .

  If comprised in this way, each of the other drive shaft will drive relatively on the basis of one drive shaft, and each track | orbit of a drive shaft will become fixed irrespective of the conveyance speed of a to-be-conveyed object. Moreover, it is not necessary to specify teaching points other than the start point, singular point, and target point.

  According to a second aspect of the present invention, in the configuration of the first aspect of the invention, the speed condition of each drive shaft and the operation in which each drive shaft operates while the robot operates from the starting point or the target point to the singular point. Time calculating means for calculating the operation time of each drive shaft from the quantity is further provided, and the reference axis is the drive shaft having the longest calculated operation time among the drive shafts.

  If comprised in this way, each of the other drive shaft will drive relatively on the basis of the drive shaft with the longest operation time.

  According to a third aspect of the present invention, in the configuration of the first or second aspect of the present invention, the operating means is configured such that the operation unit divides the time during which the robot operates from the start point or target point to the singular point at predetermined intervals. Each of the drive shafts is driven at the calculated operation ratio.

  If comprised in this way, the position and attitude | position of a robot will be controlled for every predetermined time.

  According to a fourth aspect of the present invention, in the configuration of the first aspect of the present invention, the arm mechanism is configured such that the arm mechanism has a hand member predetermined at one end via the first drive shaft of the drive shafts. An upper arm member that supports the upper arm member so as to be pivotable in the plane direction, and the other end of the upper arm member is pivotally supported in the planar direction via the second drive shaft of the drive shafts at one end. And a lower arm member supported by the base member so as to be rotatable in a plane direction via a third drive shaft of the drive shafts.

  If comprised in this way, the track | orbit of a drive shaft will be formed in a predetermined plane.

  As described above, according to the first aspect of the present invention, each drive shaft operates relative to one drive shaft, and each track of the drive shaft is constant regardless of the transport speed of the object to be transported. It becomes. Moreover, it is not necessary to specify teaching points other than the start point, singular point, and target point. For this reason, when the trajectory of the drive shaft is limited in order to avoid interference with an obstacle, a singular point can be passed and the conveyance speed can be improved. Since the number of teaching points is reduced, the startup time of the apparatus can be shortened.

  According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, each of the other drive shafts is relatively driven on the basis of the drive shaft having the longest operation time. The operation time of the longest drive shaft can be adjusted to be an efficient robot control device.

  In addition to the effect of the invention of claim 1 or 2, the invention described in claim 3 controls the position and posture of the robot every predetermined time. Accuracy can be improved.

  In addition to the effect of the invention according to any one of claims 1 to 3, the invention according to claim 4 is easy to adjust the orbit of the drive shaft because the orbit of the drive shaft is formed on a predetermined plane. It becomes.

  Next, embodiments of the invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a robot control system to which a robot control apparatus according to a first embodiment of the present invention is applied.

  Referring to FIG. 1, a 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 a command to the servo amplifier 15 to control the operation, position, and posture of the robot 11.

  The robot 11 includes a hand member 22 that holds the object to be transported, an upper arm member 20 that supports the end of the hand member 22 so that the end of the hand member 22 can be rotated in the horizontal direction via the W axis 21 at one end, and B A lower arm member 18 that supports the other end of the upper arm member 20 via a shaft 19 so as to be pivotable in the horizontal direction, and a second arm that supports the other end of the lower arm member 18 via a shaft 17 so as to be pivotable in the horizontal direction. The base member 16 is provided. The upper arm member 20 is disposed below the hand member 22, the lower arm member 18 is disposed below the upper arm member 20, and the base member 16 is disposed below the lower arm member 18. The hand member 22 is formed in an elongated U shape in plan view, and the W axis 21 is disposed so that the bent portion side becomes a base point. The hand member 22 includes holding means such as vacuum suction (not shown), and the object to be conveyed is fixed to the upper surface of the hand member 22 by the holding means. The lower arm member 18 and the upper arm member 20 are formed in an elongated flat plate shape, and the length of each of the lower arm member 18 and the upper arm member 20 is fixed when the lower arm member 18 is fixed and the upper arm member 20 is rotated about the B axis 19. The length is set such that the A axis 17 and the W axis 21 overlap. The base member 16 is formed in a quadrangular prism shape whose longitudinal direction is the vertical direction, and is configured to accommodate an A-axis 17 formed in a cylindrical shape whose longitudinal direction is the vertical direction. The W axis 21 constitutes the first drive axis, the B axis 19 constitutes the second drive axis, the A axis constitutes the third drive axis, and the upper arm member 20, the B axis 19 and the lower arm member 18 constitute the arm mechanism. Constitute.

  The A axis 17, the B axis 19, and the W axis 21 are drive axes, and a servo motor (not shown) is installed on each drive axis. The A-axis 17 is a servo motor for rotating the lower arm member 18, the B-axis 19 is a servo motor for rotating the upper arm member 20, and the W-axis 21 is for rotating the hand member 22. Each servo motor is installed. The rotation shaft, which is the output shaft of each servo motor, is connected to each of the lower arm member 18, the upper arm member 20, and the hand member 22, so that the lower arm member 18, the upper arm member 20 and the hand member 22 are independent of each other. And can be 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). By this operation amount detection means, the rotation angles of the lower arm member 18, the upper arm member 20, and the hand member 22 are detected. Furthermore, a servo motor or a cylinder (not shown) for raising and lowering the A shaft 17 in the vertical direction is installed in the A shaft 17 inside the base member 16. The elevation distance of the A-axis 17 is detected by an encoder (not shown) that is a height detection means.

  Since the base member 16 is installed at a predetermined position, the A-axis 17 does not move, and the hand member 22 moves in a predetermined range in the horizontal direction with the A-axis 17 as a base point. When the A-axis 17 moves up and down, the lower arm member 18, the upper arm member 20, and the hand member 22 that are connected to each other move up and down together. 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 A-axis 17, B-axis 19 and W-axis 21 based on the command signal from the control unit 14 to drive the servo motor. Also, the servo amplifier 15 drives the servo motor so that the detection information such as the rotation angle from the encoder is fed back to the servo amplifier 15 and the difference between the command signal from the control unit 14 and the feedback signal from the encoder is eliminated. Control. This control is performed by PI control, PID control or the like, but is not limited.

  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 for obtaining 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. 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 schematic plan view showing the position and posture of the robot at each point when the robot shown in FIG. 1 passes the singular point O and transports the semiconductor wafer from the start point S to the target point E. FIG. The singular point in this embodiment is that the semiconductor wafer when the center point of the semiconductor wafer is on the center line of the hand member 22 and the center lines of the lower arm member 18, the upper arm member 20 and the hand member 22 are overlapped. The center point of the wafer 23 is used.

  Referring to FIG. 2, the robot 11 described above includes a cassette 24 in which a semiconductor wafer 23 that is an object to be transferred arranged so as to extend in the Y direction, and a semiconductor wafer 23 arranged in parallel to the cassette 24. It is installed between the processing devices 25 that perform processing. The robot 11 loads and unloads the semiconductor wafer 23 from the cassette 24 and the processing apparatus 25 and transports the semiconductor wafer 23 between the cassette 24 and the processing apparatus 25. The width between the cassette 24 and the processing device 25 is slightly larger than the size when the lower arm member 18 and the upper arm member 20 are aligned in the X direction in the axial direction. Therefore, if the lower arm member 18 and the upper arm member 20 are operated without restricting their trajectories, they will interfere with the cassette 24 and the processing device 25. The robot 11 is installed so as to operate in the same range as the left and right with the axis in the X direction as a boundary. The robot 11 operates to transfer the semiconductor wafer 23 so that the center of the semiconductor wafer 23 moves from the start point S through the singular point O to the target point E. At this time, the robot 11 operates so that the semiconductor wafer 23, the hand member 22, and the upper arm member 20 do not interfere with the obstacles of the cassette 24 and the processing apparatus 25.

  2 shows the position and posture of the robot 11 at the start point S, FIG. 2 (2) shows the singular point O, and FIG. . First, the control unit 14 drives the robot 11 in the clockwise direction, and drives the B axis 19 and the W axis 21 in the counterclockwise direction, thereby starting the robot 11 as shown in FIG. The operation is performed from the position and posture of the point S to the position and posture of the singular point O shown in (2) of FIG. Next, the A axis 17 and the W axis 21 are driven clockwise, and the B axis 19 is driven counterclockwise, whereby the robot 11 is moved to the position of the singular point O shown in (2) of FIG. And from the attitude to the position and attitude of the target point E shown in (3) of FIG. When passing through the singular point O, the A axis 17 and the B axis 19 rotate in the same direction, but the W axis 21 rotates in the opposite direction, and the robot 11 stops once at the singular point O. If the trajectory of each drive shaft is free from the start point S to the target point E, the semiconductor wafer 23, the hand member 22, and the upper arm are being transported while the semiconductor wafer 23 is being transferred from the start point S to the target point E. The member 20 will interfere with the obstacle of the cassette 24 and the processing apparatus 25. In the case of a conventional robot control device, it is necessary to designate a plurality of teaching points as relay points in order to avoid interference with an obstacle and passage of a singular point O. However, the teaching points in this operation of the robot controller 12 are the starting point S, the singular point O, and the target point E.

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

  FIG. 3 is an enlarged plan view of the posture of the robot at the start point S shown in FIG. FIG. 4 is a diagram when the robot is operated from the starting point S to the singular point O shown in FIG. 2, and (1) is a diagram showing the difference in operation amount, operation time and operation ratio of each drive axis. (2) is a diagram showing a change in speed of each drive shaft, and (3) is a diagram showing a trajectory of the center point of the semiconductor wafer.

Referring to FIG. 3, the robot 11 controls the robot 11 to carry the semiconductor wafer 23 so that the center of the semiconductor wafer 23 moves from the start point S to the singular point O. A difference θ between the movement amounts of the A axis 17, the B axis 19, and the W axis 21 in the attitude of the start point S with respect to the attitude of the singular point O of the robot 11 is shown. That is, the angle between the X axis and the lower arm 18, the angle between the lower arm 18 and the upper arm 20, and the angle between the upper arm 20 and the hand member 22 in the posture of the starting point S are shown. When the counterclockwise direction in the plan view is (+) and the clockwise direction is (−), the difference θ is −θ _{AS for the} A axis 17, θ _{BS for the} B axis 19, and θ _WS for the W axis 21. Although the posture of the robot 11 moves from the starting point S to the singular point O, the control unit 14 drives the A axis 17 clockwise by an amount of movement of θ _AS , and lower arm about the A axis 17 The member 18 is rotated. Further, the B-axis 19 is driven by the operation amount of theta _BS counterclockwise clockwise direction, the upper arm member 20 is rotated by the B axis 19 in the center. In addition, the hand member 22 is rotated by driving the W shaft 21 counterclockwise by an operation amount of θ _WS .

Referring to (1) in FIG. 4, first, the control unit 14 uses the detection information from the encoders attached to each of the drive shafts to calculate the difference θ of each of the drive shafts by the difference calculation means. calculate. Next, the control unit 14 uses the time calculation means to set each speed condition of the drive shaft that can be set in advance and the amount of movement that the robot 11 operates from the attitude of the start point S to the attitude of the singular point O, that is, the difference θ From the above, the operation time T of each drive shaft is calculated. It is assumed that the operation time T calculated at this time is T _{AS for the} A axis 17, T _{BS for the} B axis 19, and T _WS for the W axis 21, and the operation time T _BS for the B axis 19 is the longest. Next, the control unit 14 uses the B axis 19 that is the drive axis with the longest calculated operation time T among the drive axes as a reference axis by the ratio calculation means, and determines the other drive axis for the operation amount of the reference axis. The movement ratio of the movement amounts of the A axis 17 and the W axis 21 is calculated. As shown in (1) of FIG. 4, the motion ratio calculated at this time is such that the B axis 19 is 1, the A axis 17 is (−θ _AS / θ _BS ), and the W axis 21 is (θ _WS / θ). _BS ). By setting the drive axis having the longest operation time T as the reference axis, the transport time can be matched with the operation time of the drive axis having the longest operation time, and the robot control apparatus 12 becomes efficient. Although the reference axis is determined based on the length of the operation time T, the reference axis may be determined based on the amount of operation such as an angle.

Next, the controller 14 causes the robot 11 to start the starting point S by driving each of the drive shafts of the A-axis 17, the B-axis 19 and the W-axis 21 with the servo motor at the calculated motion ratio. To the posture of the singular point O. The control unit 14 sends a command signal to the servo amplifier 15 every predetermined time ΔT obtained by dividing the time during which the robot 11 moves from the starting point S to the singular point O at predetermined intervals, for example, every interpolation time of about several milliseconds. Each of the drive shafts is driven at the above movement ratio. Specifically, if the B-axis 19 to theta _BN driven during the N-th predetermined time [Delta] T _N, the operation amount for driving the A-axis 17 and the W-axis 21 during a predetermined time [Delta] T _N theta _AN and theta _WN Is
θ _AN = θ _BN × (−θ _AS / θ _BS ) = − [θ _BN × (θ _AS / θ _BS )]
_{θ WN = θ BN × (θ} WS / θ BS)
It becomes. Control unit 14, theta _BN only drives the B-axis 19 in a counter clockwise direction during a predetermined time [Delta] T _N by the servomotor, the A-axis 17 in the clockwise direction _{[θ BN × (θ AS /} θ BS)] The W axis 21 is driven counterclockwise by [θ _BN × (θ _WS / θ _BS )]. Therefore, the control unit 14 does not drive the A axis 17, the B axis 19 and the W axis 21 independently of each other, but relatively moves the A axis 17, the B axis 19 and the W axis 21 at the above operation ratio. Driven.

  Next, the speed change of each drive shaft and the trajectory of the central point of the semiconductor wafer 23 when the robot 11 operates from the start point S to the singular point O will be described.

Referring to (2) in FIG. 4, the vertical axis represents the speed of each drive shaft, and if the rotation direction of the drive shaft is counterclockwise (+), the vertical axis is clockwise. (-). On the horizontal axis, the elapsed time until the robot 11 moves from the posture of the start point S to the posture of the singular point O is taken. Each of the drive shafts starts driving simultaneously and stops simultaneously. Each speed of the drive shaft increases from the start point S, decelerates after passing through the highest speed point, and stops at the singular point O. The speed of the B axis 19 is the fastest, followed by the W axis 21 and the A axis 17 in this order. The B-axis 19 and the W-axis 21 are rotated counterclockwise, and the A-axis 17 is rotated clockwise. Since the above-described operation control of the robot 11 is performed, the speed of each drive shaft changes as shown in (2) of FIG. 4, and the A axis 17, B between the start point S and the singular point O The speed ratio of each of the shaft 19 and the W shaft 21 is always constant. That is, the operation ratio of each of the A axis 17, the B axis 19, and the W axis 21 is
A-axis 17: B-axis 19: W-axis 21 = (− θ _AS / θ _BS ): 1: (θ _WS / θ _BS )
Always constant.

  Referring to (3) in FIG. 4, the vertical axis represents the X direction coordinate, the horizontal axis represents the Y direction coordinate, and the X and Y direction coordinates shown in FIGS. Is consistent with The center trajectory of the semiconductor wafer 23 moves along the axis in the Y direction from the starting point S, once exceeds the axis in the X direction, and then suddenly bends to a singular point O located on the axis in the X direction. Has reached. The trajectory is formed so as to draw a smooth curve so as to move in an elliptical shape extending in the Y direction.

  As described above, the operation control of the robot 11 has been described from the posture of the start point S to the posture of the singular point O. From the singular point O shown in (2) of FIG. 2 to (3) of FIG. The operation up to the target point E is also controlled by the same operation control. Consider the starting point S described above as a singular point O and the singular point O as a target point E. The control unit 14 relatively drives the A axis 17, the B axis 19, and the W axis 21 at a constant operation ratio from the singular point O to the target point E. The motion ratio at this time is different from the motion ratio from the start point S to the singular point O described above. The speed of each drive shaft from the start point S to the target point E rises from the start point S, reaches the highest speed point, decelerates, stops once at the singular point O, rises again, and rises again to the highest speed point. After reaching, the vehicle decelerates and stops simultaneously at the target point E. In addition, unlike the case shown in FIG. 2, if the start point and the target point are symmetrical in the plan view with the X axis as the boundary, it is not necessary to rotate the drive shaft in the opposite direction with the X axis as the boundary. . The operation ratio of each drive shaft is also the same from the starting point to the singular point O and from the singular point O to the target point. Therefore, there is no need to designate the singular point O as a teaching point, and the robot 11 can be controlled from the start point to the target point without stopping at the singular point O.

  In the robot controller 12 that controls the robot 11 as described above, each of the A axis 17, the B axis 19, and the W axis 21 operates relatively based on the operation ratio based on the drive axis with the longest operation time. To do. Therefore, even if the transport speed of the semiconductor wafer 23 from the starting point S to the singular point O or from the singular point O to the target point E changes, the trajectory of each drive shaft is constant. Since each trajectory of the drive shaft is controlled, it is not necessary to specify teaching points other than the start point S, the singular point O, and the target point E even if it is necessary to avoid interference with an obstacle. Therefore, when the trajectory of the drive shaft is limited to avoid interference with an obstacle, the number of teaching points is reduced and singular points can be passed, so that the conveyance speed is improved and the apparatus is started up. It is possible to shorten the time and the change time of the transport route.

  According to the robot control device 12, the robot 11 can be operated while avoiding interference with an obstacle in an apparatus in which the operating range of the robot 11 is limited. Moreover, since the operating range of the robot 11 can be reduced, the apparatus in which the robot 11 is installed can also be reduced. Further, since the position and posture of the robot 11 are controlled every predetermined time ΔT, it is possible to improve the accuracy of the trajectories of the drive shafts with respect to changes in the conveyance speed. Each of the drive shafts rotates in the horizontal direction, and each track of the drive shaft is formed on a horizontal plane that is a predetermined plane, so that the track of the drive shaft can be easily adjusted.

  In the above-described embodiment, the hand member and the arm mechanism are rotated in the horizontal direction. However, the configuration is not necessarily required, and the hand member and the arm mechanism may be rotated in another plane direction. For example, the robot control device may be applied to a vertically articulated robot.

  In the above-described embodiment, the driving shaft is configured by three driving shafts. However, the driving shafts may be configured by two or four or more driving shafts as long as each of the driving shafts can be driven relatively.

  Furthermore, in the above-described embodiment, the arm member is composed of two arm members. However, the arm member may be composed of three or more arm members as long as each arm member can be operated relatively.

  Furthermore, in the above embodiment, the two arm members are configured to have the same length, but may be configured to have different lengths.

  Furthermore, in the above embodiment, the arm mechanism is supported by the base member. However, the arm mechanism may be supported by a member having another configuration, and the A-axis may not be moved up and down.

  Furthermore, in the above embodiment, the drive axis with the longest operating time T is used as the reference axis, but another drive axis may be used as the reference axis.

  Furthermore, in the above embodiment, three teaching points are designated as the start point, singular point, and target point. However, if the singular point is included, three or more teaching points may be designated.

  Further, in the above embodiment, the hand member is configured to hold the object to be conveyed by vacuum suction or the like. However, if the object to be conveyed can be held, the hand member to sandwich the object to be conveyed, etc. Other configurations may be used.

1 is a block diagram showing a schematic configuration of a robot control system to which a robot control apparatus according to a first embodiment of the present invention is applied. FIG. 2 is a plan view showing the position and orientation of the robot at each point when the robot shown in FIG. 1 passes a singular point O and transports a semiconductor wafer from a start point S to a target point E. FIG. 3 is an enlarged plan view of a posture of a robot at a start point S shown in FIG. FIG. 3 is a diagram when the robot is operated from the starting point S to the singular point O shown in FIG. 2, and (1) is a diagram showing a difference in the operation amount of each drive axis, an operation time, and an operation ratio; (2) is a diagram showing the speed change of each drive shaft, and (3) is a diagram showing the trajectory of the center point of the semiconductor wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Robot 12 Robot controller 16 Base member 17 A axis 18 Lower arm 19 B axis 20 Upper arm 21 W axis 22 Hand member 23 Semiconductor wafer

Claims (4)

A robot control device that controls a robot to move an object to be conveyed by moving between a starting point and a target point with a singular point in between,
The robot has a plurality of drive shafts and holds a transported object, and an arm mechanism that rotatably supports the hand member at one end via one of the drive shafts. A base member that rotatably supports the other end of the arm mechanism via one of the drive shafts,
Dividing the movement of the robot from the starting point to the singular point and the movement of the robot from the singular point to the target point, for each of the divisions,
A difference calculating means for calculating a difference in the amount of movement of each of the drive axes at the start point or the target point with respect to the singular point of the robot;
Ratio calculation means for calculating one of the drive shafts as a reference axis and calculating an operation ratio of the difference of the other drive shaft with respect to the difference of the reference axis;
A robot control apparatus comprising: an operation unit that operates each of the drive axes at the calculated operation ratio to operate the robot from the start point or the target point to the singular point. The operation time of each of the drive axes is determined from the speed condition of each of the drive axes and the amount of movement of each of the drive axes while the robot operates from the start point or the target point to the singular point. It further comprises time calculation means for calculating,
The robot control apparatus according to claim 1, wherein the reference axis is a drive axis having the longest calculated operation time among the drive axes.   The operation means drives each of the drive shafts at the calculated operation ratio every predetermined time obtained by dividing the time during which the robot operates from the start point or the target point to the singular point at a predetermined interval. The robot control apparatus according to claim 1 or 2.   The arm mechanism includes an upper arm member that supports the hand member so as to be rotatable in a predetermined plane direction via a first drive shaft of the drive shaft at one end, and of the drive shaft at one end. The other end of the upper arm member is rotatably supported in the plane direction via a second drive shaft, and the other end is rotatable in the plane direction via a third drive shaft of the drive shafts. The robot control device according to claim 1, further comprising a lower arm member supported by the base member.

Images