JP2012210676A - Robot arm type transport apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot arm type transport apparatus which can appropriately detect a held state of a transport object without causing an increase in the size of an end effector for holding the transport object article, damage to a sensor and deterioration in transport efficiency.SOLUTION: The robot arm type transport apparatus includes: an arm mechanism 2 configured by connecting a plurality of links 21. 22, 23 including a first link 21 for holding a transport object W in such a manner that the links 21. 22, 23 move pivotally in a horizontal plane via joints 24, 25, 26; and a sensor 3 which is attached to, among the plurality of links constituting the arm mechanism 2, the link 22 closer to a proximal end rather than the first link 21 and which detects the presence of the transport object W in a detection position Se defined according to the attached position. The attached position of the sensor 3 is set in such a manner that, when the joint 24 is pivotally driven in a direction in which the first link 21 approaches the link 22 with the sensor 3 attached thereto, the transport object W regularly held by the first link 21 passes through the detection position Se and is detected.

Description

  The present invention relates to a robot arm type transfer device configured by connecting a plurality of links in a rotatable manner, and more particularly to a robot arm type transfer device having an optimized function for detecting a holding state of a transfer object.

  2. Description of the Related Art A transport device that transports a transport target such as a thin semiconductor wafer according to a manufacturing process is known. Among them, a plurality of links are connected in series via a joint portion so as to be rotatable, and each joint portion is rotationally driven, so that one piece of transport object is stored from a storage case that stores the transport target object at a predetermined pitch. There is a robot arm type transfer device that takes out and conveys each one.

  In such a robot arm, an end effector (first link), which is a link at the tip, is provided with a holding unit for holding an object to be conveyed. There are various means for holding the object to be transported, such as a method of holding by vacuum suction, a method of holding by a mechanical chuck, and a method of simply placing it. It is necessary to detect whether an object is properly held.

  As one means for that purpose, Patent Document 1 discloses that an end effector is provided with a sensor such as a photo sensor or an electrostatic sensor that detects the presence or absence of an object to be conveyed.

JP 2002-270674 A

  However, the robot arm type transfer apparatus as described above is required to be as small as possible in the end effector so that the end effector can enter and exit in a narrow space such as the inside of a storage case with a short wafer storage pitch. However, in the configuration in which the sensor is provided in the end effector itself as described above, a space for attaching the sensor is required for the end effector, and the end effector itself is increased in size. Moreover, for example, when the end effector is moved in and out of the high temperature region and the low temperature region inside the processing apparatus, the sensor may enter and exit the high temperature region and the low temperature region together with the end effector, and the sensor may be damaged.

  On the other hand, as one means for avoiding the above problem, it is conceivable to attach a sensor for detecting the presence or absence of a conveyance object in the end effector to another apparatus other than the robot arm type conveyance apparatus. It is necessary to transport the object to be transported to a predetermined detection position of a sensor provided in a separate device each time it is necessary to ensure the transport efficiency, which impairs transport efficiency.

  The present invention has been made paying attention to such a problem, and its purpose is to carry the transfer without enlarging the size of the end effector holding the transfer object, damaging the sensor, or reducing the transfer efficiency. It is an object of the present invention to provide a robot arm type transfer device that can appropriately detect a holding state of an object.

  In order to achieve this object, the present invention takes the following measures.

  That is, the robot arm-type transfer device of the present invention includes an arm mechanism configured by connecting a plurality of links including a first link holding a transfer object so as to be rotatable in a horizontal plane via a joint portion; A sensor that is attached to a link closer to the base end side than the first link among the plurality of links constituting the arm mechanism, and that detects the presence of the conveyance object at a detection position determined according to the attachment position. Thus, when the joint portion is rotationally driven in the direction in which the first link approaches the link to which the sensor is attached, the conveyance object that is normally held by the first link has the detection position. The mounting position of the sensor is set so that it can be detected by passing through.

  In this way, the conveyance object normally held by the first link passes through the detection position and is detected only by rotationally driving the joint portion in the direction in which the first link approaches the link to which the sensor is attached. Since the attachment position of the sensor is set so that it is possible, it can be detected whether or not the first link holds the object to be conveyed, and other than the conveying device to detect the presence or absence of the object to be conveyed Therefore, it is not necessary to transport the transport object to a predetermined detection position provided in another apparatus, and transport efficiency can be improved. And since the sensor is attached to the link of the base end side rather than the 1st link holding a conveyance subject, compared with the case where the sensor is attached to the 1st link (end effector) like before. The first link can be thinned, and for example, it is possible to meet the demand for the first link to enter and exit in a narrow space such as the inside of a storage case with a short storage pitch. Furthermore, since the sensor is attached to the link on the proximal end side relative to the first link holding the conveyance object, for example, when the first link enters and exits the high temperature region and the low temperature region inside the processing apparatus. However, it is possible to avoid the sensor from being damaged by avoiding the sensor entering and exiting the high temperature region and the low temperature region together with the first link.

  In order to detect not only whether or not the conveyance object W is held, but also whether or not the conveyance object is held in a state shifted from a predetermined position, the conveyance object is moved at a predetermined speed. Measuring the time required for one end to the other end of the conveyance object to pass through the detection position, and an error between the measured time and the predetermined time when held at the predetermined position of the first link It is preferable that a determination unit that determines whether or not the object to be conveyed is displaced from the predetermined position is provided.

  Since the present invention is configured as described above, it is determined whether or not the conveyance object is held by merely rotating the joint in a direction in which the first link approaches the link to which the sensor is attached. It is possible to detect, and it is possible to improve the conveyance efficiency by reducing unnecessary operations as much as possible. Moreover, since the sensor is attached to the link on the base end side relative to the first link holding the object to be conveyed, the first link can be reduced in size by eliminating the sensor installation space, and the sensor together with the first link. It is possible to prevent the sensor from being damaged by avoiding entering and exiting the high temperature / low temperature region. Therefore, it is possible to provide a robot arm type transfer device that can appropriately detect the holding state of the transfer object without causing these problems.

The perspective view which shows the robot arm type conveying apparatus which concerns on one Embodiment of this invention. The perspective view which shows operation | movement of a robot arm. The expansion perspective view which shows the sensor part of a robot arm. The top view which shows typically operation | movement of a robot arm. The schematic diagram which compares and shows the state which hold | maintains the conveyance target object in a predetermined position, and the state hold | maintained and shifted | deviated from the predetermined position.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 4, the robot arm type transfer apparatus of the present embodiment includes a plurality of links including a first link 21 that is also called an end effector that holds a transfer object W such as a disk-shaped semiconductor wafer. The arm mechanism 2 constituted by connecting the 21, 22 and 23 so as to be rotatable in the horizontal plane via the joint portions 24, 25 and 26, and the conveyance object W held by the first link 21 are detected. For controlling the rotation of the joints 24, 25, and 26 in the arm mechanism 2 and the control unit that transports the transport object W held by the first link 21 to a desired position. 4.

  As shown in FIGS. 1 and 4, the arm mechanism 2 includes a first link 21 that holds the conveyance object W on the distal end side, and a base end portion 21 b of the first link 21 on the distal end portion 22 a in a horizontal plane. A second link 22 that is pivotably connected, a third link 23 that is pivotally connected to a distal end portion 23a of a base end portion 22b of the second link 22, and a third link 23 And a base 20 that rotatably supports the base end portion 23b in a horizontal plane. The first link 21 is substantially Y-shaped and plate-shaped in plan view, and has a stepped portion 21c having a shape corresponding to the periphery of the disk-shaped transport object W on the upper surface. The step portion 23c is a mounting surface on which the conveyance target object W is placed, and exhibits a function of holding the conveyance target object by being formed lower on the inner peripheral side than on the outer peripheral side. The proximal end portion 21b of the first link 21 and the distal end portion 22a of the second link 22 are connected to each other so as to be rotatable in a horizontal plane around the rotation axis C1 along the vertical direction. It is composed. Similarly, the proximal end portion 22b of the second link 22 and the distal end portion 23a of the third link 23, the proximal end portion 23b of the third link 23, and the base 20 are also rotational axes C2 along the vertical direction. The second joint portion 25 and the third joint portion 26 are configured to be pivotable within a horizontal plane around C3. Each of the joint portions 24, 25, and 26 is configured to be able to change the angle θ of each link 21, 23, and 24 by being driven to rotate independently of the other joint portions by a power unit M using a motor or the like. (See FIG. 4).

  As shown in FIG. 3, the sensor 3 for detecting the conveyance object W is such that the conveyance object W is at a detection position Se corresponding to the attachment position, such as a photoelectric sensor including a light emitting element 30 and a light receiving element 31. Whether the transport object W passes through the detection position Se, which is a light path connecting the light emitting element 30 and the light receiving element 31, and the light traveling from the light emitting element 30 toward the light receiving element 31 is blocked. The conveyance object W is detected according to whether or not. As shown in FIGS. 1 to 4, the sensor 3 includes a base of a second link 22 that is closer to the base end side than the first link 21 among the plurality of links 21, 22, and 23 constituting the arm mechanism 2. As shown in FIGS. 2 and 4, the first joint portion 24 is rotationally driven in a direction in which the first link 21 approaches the second link 22 to which the sensor 3 is attached. In this case, the attachment position of the sensor 3 is set so that the conveyance object W that is normally held by the first link 21 can be detected through the detection position Se. Further, the mounting position of the sensor 3 is set so as not to interfere with the plurality of links 21, 22, and 23 when the joint portions 24, 25, and 26 are rotationally driven. That is, it can be said that the sensor 3 is attached at a position avoiding the rotation trajectory of each of the links 21, 22, and 23.

  The control unit 4 shown in FIGS. 1 and 2 is composed of a normal microcomputer unit having a CPU, a memory and an interface, and a necessary program such as a transfer control routine is written in the memory. By calling and executing a necessary program, the determination unit 41 that determines a desired transfer operation and a holding state of the transfer object W is realized in cooperation with peripheral hardware resources.

  The determination unit 41 executes a holding state check process using the sensor. That is, as shown in FIG. 4A, only the first link 21 is inserted into a storage case Ca such as a FOUP (Front Open Unified Pod) as a transfer source, and a semiconductor wafer or the like is transferred by the first link 21. When the operation of holding the object W and taking out the conveyance object W from the storage case Ca is performed, as shown in FIGS. 2 and 4B, the second link 22 to which the sensor 3 is attached is attached. On the other hand, the first joint portion 24 is rotationally driven in a direction in which the first link 21 is brought closer to move the transport object W that would be held by the first link 21 and pass the detection position Se. In this case, the sensor when the angle θ of the first link 21 with respect to the second link 22 is a predetermined angle (for example, 180 degrees, see FIG. 4B) at which the conveyance target W is at the detection position Se. The holding state of the conveyance object W is determined according to the detection result 3. Specifically, when the shielding state is detected by the sensor 3, it is determined that the conveyance object W is held, and the next conveyance operation is performed, while the light transmission state is detected by the sensor 3. In this case, it is determined that the conveyance object W is not held, and the process proceeds to error processing.

  As described above, the robot arm type transfer device according to the present embodiment is configured so that the plurality of links 21, 22, and 23 including the first link 21 that holds the transfer object W are connected to the horizontal plane via the joint portions 24, 25, and 26. An arm mechanism 2 configured to be pivotably connected within the first link 21 and a link 22 that is proximal to the first link 21 among the plurality of links 21, 22, and 23 constituting the arm mechanism 2, And a sensor 3 that detects the presence of the conveyance object W at a detection position Se that is determined according to the attachment position, and the joint portion 24 in a direction in which the first link 21 approaches the link 22 to which the sensor 3 is attached. The attachment position of the sensor 3 is set so that the conveyance object W normally held by the first link 21 can be detected by passing through the detection position Se.

  In this way, the conveyance object W that is normally held by the first link 21 is detected simply by rotationally driving the joint portion 24 in the direction in which the first link 21 approaches the link 22 to which the sensor 3 is attached. Since the attachment position of the sensor 3 is set so that it can be detected by passing through the position Se, it can be detected whether or not the first link 21 holds the conveyance object W. In order to detect the presence or absence of W, there is no need to transport the transport object to a predetermined detection position provided in another device other than the transport device, and transport efficiency can be improved. Moreover, since the sensor 3 is attached to the link 22 on the proximal end side with respect to the first link 21 that holds the conveyance object W, the sensor is attached to the first link (end effector) as in the past. Compared to the case, the first link can be made thinner, and for example, it is possible to meet the demand for the first link to enter and exit in a narrow space such as the inside of a storage case with a short storage pitch. Furthermore, since the sensor is attached to the link 22 on the proximal end side with respect to the first link 21 holding the conveyance object W, for example, when the first link enters and exits the high temperature region and the low temperature region inside the processing apparatus. Even so, it is possible to prevent the sensor from being damaged by avoiding the sensor from entering and exiting the high temperature region and the low temperature region together with the first link.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the present embodiment, the sensor 3 is attached to the second link 22. However, the sensor 3 is not limited to this as long as it is a base end side link relative to the first link 21. For example, the third link 23 may be attached. In the present embodiment, the arm mechanism is configured by connecting the three links 21 to 23 so as to be rotatable in a horizontal plane, but may be configured by connecting two or four or more links.

Moreover, in this embodiment, although it is comprised so that it may detect whether the conveyance target object W is hold | maintained at the 1st link 21, as shown in FIG. You may comprise so that it may be determined whether it hold | maintains in the state shifted | deviated from the regular predetermined position p1 in the link 21. FIG. That is, the time t required to move the transport object W at a predetermined speed (for example, speed V) to pass the detection position Se from one end eg1 to the other end eg2 of the transport object W is measured. whether the transport object W in response to is positioned displaced from the predetermined position p1 the error between the predetermined time t _s when held in a predetermined position p1 of the first link 21 (| | t-t s ) The determination part 41 which determines whether is provided. Specifically, when the center P of the conveyance target W coincides with the predetermined position p1 (a state where the determination unit 41 is held at the predetermined position), the determination unit 41 moves from one end eg1 to the other end eg2 of the conveyance target W. set in advance the predetermined time t _s required to pass through the detection position Se, error between the time measured t and the predetermined time t _s, if is within the predetermined range ((| | t-t s ) | t −t _s | ≦ th, th indicates a predetermined threshold value), while it is determined that the conveyance object W is held at the predetermined position p1, while the error (| t−t _s |) is not within the predetermined range. (| T−t _s |> th), it is determined that the conveyance object W is held in a state of being displaced from the predetermined position p1. With this configuration, it is determined whether or not the transport object W is held on the first link 21 only by rotating the joint portion 24 and passing the transport object W through the detection position Se at a predetermined speed. In addition to detection, it is possible to detect whether or not the conveyance object W is held in a state of being displaced from the predetermined position p1 in the first link 21. If there is a notch in the peripheral edge (edge) of the wafer that is the transfer object W, a portion that avoids the notch (notch) may pass through the detection position Se.

  Furthermore, in this embodiment, a transmissive photoelectric sensor is used as the sensor, but a reflective photoelectric sensor may be used.

  Furthermore, the trajectory correction described above is applied to a transport device provided with an arm mechanism configured by connecting a plurality of links in series in a rotatable manner. However, the trajectory correction is applied to a transport device using other arm mechanisms. Is also applicable. For example, a transport device such as a parallel manipulator in which a plurality of links are connected in parallel can be used.

  In addition, in this embodiment, it is configured to hold the transfer object W by placing the transfer object W such as a wafer on the first link (end effector), but vacuum suction, mechanical chuck, etc. It may be configured to hold the conveyance object W.

  The specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

2 ... Arm mechanisms 21, 23, 24 ... Multiple links 21 ... First links 22 ... Links 24, 25, 26 with sensors attached ... Joint part 3 ... Sensor 41 ... Determination part Se ... Detection position V ... Predetermined speed W ... Conveyed object (wafer)
eg1 ... other end t ... measured time t s _... predetermined time end eg2 ... transporting objects conveyed object

Claims (2)

An arm mechanism configured by connecting a plurality of links including a first link holding a conveyance object in a horizontal plane via a joint portion, and among the plurality of links constituting the arm mechanism A sensor that is attached to the link on the proximal end side relative to the first link, and that detects the presence of the conveyance object at a detection position determined according to the attachment position;
When the joint portion is rotationally driven in a direction in which the first link approaches the link to which the sensor is attached, a conveyance object that is normally held by the first link passes through the detection position and is detected. The robot arm type transfer device, wherein the mounting position of the sensor is set so as to be able to do so.   The transport object is moved at a predetermined speed, and the time required for one end to the other end of the transport object to pass through the detection position is measured and held at the measured time and the predetermined position of the first link. The robot arm type transfer device according to claim 1, further comprising a determination unit that determines whether or not the transfer object is displaced from the predetermined position in accordance with an error from a predetermined time when the transfer is performed.

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