JP2011167828A - Conveying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new conveying device which corrects a conveying track according to displacement without impairing characteristics of the conveying track before correction when correcting the preset conveying track according to the displacement. <P>SOLUTION: The conveying device is a device for conveying a conveying object along the conveying track Pt from a start point S to an end point E. In carrying out conveying control using the preset conveying track Pt, when the end point E' as a target is displaced from the end point E of the conveying track Pt, the conveying device corrects the conveying track Pt to allow the end point E of the conveying track Pt to be the target end point E'. In correcting the track Pt, the conveying device proportionally divides a deviation vector between the end point E before the correction and the target end point E' after the correction over a section from the start point S to the target end point E', gradually corrects the conveying track, into the track Pt' after the correction. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a transport device that transports a transport object along a transport track, and more particularly to a transport device in which a function for correcting a deviation between a preset transport track and a target position is optimized.

  As illustrated in Patent Document 1, the transfer device drives a transfer mechanism such as a robot arm to transfer a transfer object along a transfer track. The transport track is generated in advance offline and set in the transport device. In many cases, this transport track takes into account a reduction in transport time in order to improve transport efficiency.

JP 2003-145461 A

  When carrying out conveyance control using a preset conveyance path as described above, the position shifted from the start point and end point of the preset conveyance path due to external influences must be conveyed as a new start point and end point. In some cases, a function for correcting the conveyance trajectory in real time according to the positional deviation is required.

  One effective means for realizing such real-time correction of the transport path is to add a correction operation at the start or end of the transport operation along a preset transport path. Specifically, as shown in FIG. 7A, first, the conveyance object W is conveyed from the start point S to the end point E along a preset conveyance path Pt indicated by a solid line, and then as indicated by a broken line. A correction operation for moving from the end point E to the target end point E ′ is performed, or a correction operation for moving from the target start point S ′ to the start point S of the transport path Pt is performed as shown by a broken line in FIG. And transport from the start point S to the end point E of the transport trajectory Pt.

  However, in the case where the correction operation is added independently from the optimum transport path as described above, the shape of the pre-correction path Pt is lost due to a rapid change in the path, and the characteristics of the pre-correction path Pt are impaired. In particular, when the pre-correction trajectory Pt has characteristics suitable for shortening the transport time and suppressing vibrations, these characteristics are lost by the correction function, resulting in a decrease in transport efficiency.

  The present invention has been made paying attention to such a problem, and its purpose is to correct the conveyance trajectory set in advance according to the positional deviation without impairing the characteristics of the conveyance trajectory before correction. Another object of the present invention is to provide a new transport device that corrects the transport trajectory in accordance with the positional deviation.

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

  That is, the transport device of the present invention transports a transport object along a transport trajectory from a start point to an end point, and when performing transport control using a preset transport trajectory, the target end point is A trajectory correction unit that corrects the transport trajectory so that the end point of the transport trajectory becomes a target end point when the position is shifted from the end point of the transport trajectory, and the trajectory correction unit includes the end point before correction and the corrected end point The direction connecting the target end point is the deviation direction, the distance in the deviation direction component of the distance from the start point on the pre-correction trajectory to a certain point is the pre-correction distance, and the certain point among the points on the post-correction trajectory is When a point located on an axis along the passing deviation direction is a corresponding point and the distance of the deviation direction component of the distance from the start point on the corrected trajectory to the corresponding point is the corrected distance, the certain point is Whichever point on the orbit Also as the ratio of the pre-correction distance and the corrected distance is the same, and corrects the trajectory by enlarging or reducing the uncorrected distance along the shift direction relative to the starting point.

  The “predetermined point” means a point that may be any point that constitutes the transport path, and examples thereof include those that express the transport path continuously and those that express it discretely.

  According to this configuration, the pre-correction distance is enlarged along the deviation direction with the start point as a reference so that the ratio of the pre-correction distance and the post-correction distance is the same at any of the predetermined points on the trajectory. Or, since the trajectory is corrected by reducing the trajectory, the trajectory is gradually corrected from the start point to the target end point while substantially maintaining the shape of the trajectory before correction, and a correction operation is performed at the start and end of conveyance, etc. The position deviation of the end point can be corrected without impairing the characteristics of the track before correction due to a sudden track change.

  On the other hand, the transport device of the present invention for correcting the positional deviation of the start point transports a transport target object along the transport track from the start point to the end point, and performs transport control using a preset transport track. In doing so, it comprises a trajectory correction unit for correcting the transport trajectory so that the start point of the transport trajectory becomes the target start point when the target start point is displaced from the start point of the transport trajectory, The direction connecting the start point before correction and the target start point after correction is the shift direction, and the distance of the shift direction component of the distance from a certain point on the track before correction to the end point is the pre-correction distance. Among the distances from the corresponding point on the corrected trajectory to the end point, the point located on the axis along the deviation direction passing through the certain point is the corrected distance. The point is on the orbit Correct the trajectory by enlarging or reducing the pre-correction distance along the deviation direction with the end point as the reference so that the ratio of the pre-correction distance and the post-correction distance is the same regardless of the fixed point. It is characterized by doing.

  According to this configuration, the pre-correction distance is expanded along the deviation direction with the end point as a reference so that the ratio of the pre-correction distance and the post-correction distance is the same at any of the predetermined points on the trajectory. Or, since the trajectory is corrected by reducing the trajectory, the trajectory is gradually corrected from the target start point to the end point while maintaining the shape of the trajectory before correction, and the corrective action is performed at the start and end of conveyance, etc. The position deviation of the starting point can be corrected without impairing the characteristics of the track before correction due to a sudden track change.

  Furthermore, in order to realize the correction of the transport track with a simple calculation, the preset transport track is configured by a plurality of points including a start point and an end point, and the track correction unit configures the transport track. It is preferable to enlarge or reduce the pre-correction distance by moving each point to be moved along the deviation direction.

  In order to correct the trajectory with simple processing even if the transport trajectory is represented by the angle of each link, an articulated robot type transport mechanism in which a plurality of links are refractably connected is used. A transport device that transports the object to be transported, wherein the transport trajectory is represented by an angle of each link constituting the articulated robot, and the trajectory correction unit It is desirable to correct the angle in a direction in which the pre-correction distance is enlarged or reduced along the deviation direction.

  As described above, the present invention enlarges the pre-correction trajectory along the deviation direction so that the ratio of the pre-correction distance and the post-correction distance is the same at any of the predetermined points on the trajectory. Or, since the trajectory is corrected by reducing the trajectory, the trajectory is gradually corrected from the start point to the end point while maintaining the shape of the trajectory before correction, and a rapid trajectory such as performing a correction operation at the start or end of conveyance. The positional deviation can be corrected without deteriorating the characteristics of the pre-correction trajectory due to the change. In addition, since the characteristics of the pre-correction trajectory can be substantially maintained, the pre-correction transport trajectory can substantially maintain characteristics such as shortening the transport time and suppressing vibrations, thereby improving the transport efficiency.

The block diagram which shows typically the conveying apparatus which concerns on one Embodiment of this invention. The top view which shows the conveyance mechanism of the conveyance apparatus. Explanatory drawing regarding the conveyance track | orbit preset in the conveyance apparatus. Explanatory drawing regarding correction | amendment of a conveyance track | orbit. The flowchart which implement | achieves a track | orbit correction | amendment part performed by a conveyance control means. Explanatory drawing regarding correction | amendment of the conveyance track | orbit by the conveying apparatus of other embodiment. Explanatory drawing regarding the correction | amendment of the conventional conveyance track | orbit.

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

  As shown in FIG. 1, the transfer apparatus 1 according to this embodiment includes a transfer mechanism 2 such as a robot arm that transfers a transfer object W such as a wafer, and a transfer control of the transfer object W by driving the transfer mechanism 2. And a conveyance control means 3 for performing the above.

As shown in FIG. 2, the transport mechanism 2 is a so-called articulated robot arm in which a plurality of links 21, 22, 23 are connected in series so as to be refracted, and is transported to a holding portion 23b set at the tip of the robot arm. While the object W is placed, the angle θ _A · θ _B · θ _C between the links is changed by driving a motor (not shown) at each joint to convey the object W to be conveyed to a desired position. . The transport mechanism 2 of the present embodiment includes a first link 21 having a base end 21 a connected to the base 20, a second link 22 having a base end 22 a connected to a tip 21 b of the first link 21, And a third link 23 in which a base 23a is connected to the tip 22b of the second link 22 and a holding portion 23b for placing the conveyance object W is set on the tip. Each link 21 to 23 is horizontal. A three-axis horizontal articulated robot is configured so as to be rotatable in the direction. The lengths of the links 21 to 23 are set to L ₁ , L ₂ , and L ₃ , respectively.

  As shown in FIG. 1, the conveyance control means 3 includes a conveyance control unit 34, a trajectory correction unit 33, and trajectory data 31 stored in advance in a memory. These units 32 and 33 execute a conveyance control processing routine (not shown) in which the CPU is stored in advance in an information processing apparatus such as a microcomputer equipped with a CPU, ROM, various interfaces, a trajectory correction processing routine shown in FIG. By doing so, software and hardware are realized in cooperation. Moreover, the conveyance control means 3 is connected so as to be communicable with the positional deviation detection device SE. The positional deviation detection device SE detects a positional deviation such as the conveyance object W being displaced from the position where the conveyance object W is to be placed in the conveyance mechanism 2, and the direction and distance of the deviation. Is a device that inputs a signal indicating the above to the conveyance control means. Of course, in the present embodiment, the transport device 1 and the position shift detection device SE are separate devices, but the transport device may be provided with a position shift detection unit that performs the same function as the position shift detection device SE.

As schematically shown in FIG. 3, the trajectory data 31 divides the transport trajectory Pt through which the center of the transport target W passes by (N−1) equally at a time interval T, and includes a plurality of start points S and end points E. It is discrete data expressed by points P ₁ to _N , and the XY coordinates (X _k , Y _k ) of each point P _k are expressed by the angle θ of each link 21 to 23 constituting the transport mechanism 2 using the following equation. It is expressed as _Ak · θ _Bk · θ _Ck .
_{X k = L 1 cosθ Ak +} L 2 cos (θ Ak + θ Bk) + L 3 cos (θ Ak + θ Bk + θ Ck)
_{Y k = L 1 sinθ Ak +} L 2 sin (θ Ak + θ Bk) + L 3 sin (θ Ak + θ Bk + θ Ck)

As shown in FIG. 3, the transport control unit 34 in FIG. 1 controls the drive of the transport mechanism 2 so that the transport target W is transported along the transport trajectory Pt. The links 21 to 23 are rotationally driven so that the angles θ _A , θ _B , θ _{C of the} links 21 to 23 become the angles of the links indicated by the points P ₁ to _N constituting the transport track Pt. By carrying out sequentially for every point _{Pk to} E, the conveyance control along the conveyance track Pt is performed.

  The trajectory correction unit 33 in FIG. 1 inputs a signal related to positional deviation from the positional deviation detection device SE (processing S1 in FIG. 5), and determines a target end point E ′ shown in FIG. 4A based on this signal. (Processing S2 in FIG. 5), when the target end point E ′ is displaced from the preset end point E of the transport path Pt, the transport control is performed so that the end point E of the transport path Pt becomes the target end point E ′. The transport trajectory Pt used in the section 34 is corrected to the transport trajectory Pt ′ (processing S3 to processing S7 in FIG. 5).

Specifically, the case where the target end point E ′ is shifted only in the X direction from the end point E as shown in FIG. 4 will be described as an example. In the present embodiment, and it corrects the angle θ _{Ak ·} θ _{Bk ·} θ _Ck of each link representing the conveyor track Pt, described in XY coordinates for clarity, then the angle θ _{Ak ·} θ _{Bk ·} θ _This will be described using _Ck .

First, as shown in FIG. 4A, a direction connecting the end point E and the target end point E ′ is set as a shift direction G (in this example, a direction along the X axis), and a shift in the distance from the start point S to the end point E is detected. a distance direction component before correction distance d1 _N, the ratio of the corrected distance d2 _N for uncorrected distance d1 _N distances displacement direction component as the corrected distance d2 _N of the distance from the start point S to a target end point E '( d2 _N / d1 _N ) is calculated (step S4 in FIG. 5).

Next, the following processing is sequentially performed for each point P1 to _N constituting the trajectory Pt. As shown in FIG. 4 (a), to calculate the uncorrected distance d1 _k of the shift direction component of the distance from the starting point S to the point _{P k} (processing of FIG. 5 S5), the ratio (d2 to the distance d1 _{k N} / d1 _N ) to calculate the corrected distance d2 _k (processing S6 in FIG. 5), and the distance of the deviation direction component among the distances from the starting point S to the point P _k is calculated as shown in FIG. 4B. The point _Pk is moved along the displacement direction G so that the corrected distance d2k is _obtained (step S7 in FIG. 5). When the above processing is sequentially performed for each of the points P ₁ to _N , as shown in FIG. 4B, the pre-correction distance d 1 at any point among the points P ′ _{1 to N} constituting the corrected trajectory Pt ′. _The trajectory Pt is corrected to the trajectory Pt ′ while the ratio between _k and the corrected distance d2 _k remains the same.

φは、始点Ｓに対する目標終点Ｅ’における図２に示す第３のリンク２３のＸ軸に対する角度（第３のリンク２３の姿勢） To explain the above-mentioned correction processing at the angle θ _A · θ _B · θ _C of each link 21 to 23, the target end point E 'the XY coordinates of using the following equation the angle _{θ' A · θ 'B ·} θ' C Convert to

φ is the angle with respect to the X axis of the third link 23 shown in FIG. 2 at the target end point E ′ with respect to the start point S (the posture of the third link 23).

Next, for each of the angles θ ′ _A , θ ′ _B , θ ′ _C determined above, it corresponds to the pre-correction distance d1 _N (θ _N −θ ₁ ) and corresponds to the post-correction distance d2 _N (θ ′ _N −θ ₁ ) is calculated, and a ratio β = (θ ′ _N −θ ₁ ) / (θ _N −θ ₁ ) corresponding to the above ratio (d2 _N / d1 _N ) is calculated. The deviation direction G in the XY coordinate system is expressed as the direction of increase / decrease at the angle θ.

Then, for each point P ₁ to _N constituting the trajectory Pt using the calculated ratio β, the angle θ _A · θ _B · θ _C of each link before correction is changed to the angle θ ′ _A · θ ′ _B after correction. -The process of converting to θ ' _C is sequentially performed.
θ ′ _k = β (θ _k −θ ₁ ) + θ ₁

When the above processing is sequentially performed for each of the points P ₁ to _N , as a result, any point among the points P ′ _{1 to N} constituting the corrected trajectory Pt ′ corresponds to the pre-correction distance d1 _k (θ _k - [theta] ₁₎ and corresponding to the corrected distance d2 _k (θ _'k -θ ₁ ratio) of (ratio beta) remains the same, the trajectory Pt orbit Pt' is corrected to.

Here, considering the speed ratio between the uncorrected trajectory Pt and the corrected trajectory Pt ′,
The speed before correction is approximately (θ _k −θ _k−1 ) / T
The corrected speed is approximately (θ ′ _k −θ ′ _k−1 ) / T = β (θ _k −θ _k−1 ) / T
T is represented by a time interval between the time point k and the time point k-1, and it can be seen that the speed before and after the correction only changes by β times at each time point, and the acceleration also becomes β times. Generally, the amount of positional deviation is slightly smaller than the pre-correction distance d1 _k , and accordingly, β becomes a value close to 1 and (β−1) is also very small. The trajectory is corrected to the corrected trajectory Pt ′ while maintaining the characteristics. In addition, smooth conveyance from the start point S to the corrected target end point E ′ is possible without temporarily stopping the conveyance operation at the end point E before correction.

As described above, the transport device according to the present embodiment transports the transport target object W along the transport trajectory Pt from the start point S to the end point E, and performs transport control using the preset transport trajectory Pt. In performing, the trajectory correction unit 33 that corrects the transport trajectory Pt so that the end point E of the transport trajectory Pt becomes the target end point E ′ when the target end point E ′ is displaced from the end point E of the transport trajectory Pt. The trajectory correcting unit 33 includes a direction connecting the end point E before correction and the target end point E ′ after correction as a shift direction G, and calculates a distance from the start point S on the trajectory Pt before correction to a certain point P _k . Among them, the distance in the deviation direction component is set as the pre-correction distance d1 _k, and the point located on the axis along the deviation direction passing through the point P _k among the points on the corrected trajectory Pt ′ is corrected as the corresponding point P ′ _k. shift direction of the distance 'from the starting point S on the corresponding point P' rear track Pt to _k Same when the distance of the component was corrected distance d2 _k, the ratio of In any one point P _k is among the predetermined point on the trajectory Pt uncorrected distance d1 _k and corrected distance d2 _k Thus, the pre-correction trajectory Pt is corrected to the post-correction trajectory Pt ′ by enlarging or reducing the pre-correction distance d1 _k along the deviation direction G with the start point S as a reference.

In this way, the pre-correction distance d1 _k is deviated from the start point S so that the ratio of the pre-correction distance d1 _k and the post-correction distance d2 _k is the same at any of the predetermined points on the trajectory. Since the pre-correction trajectory Pt is corrected to the post-correction trajectory Pt ′ by enlarging or reducing along the direction G, the shape of the trajectory Pt before correction is substantially maintained to the target end point E ′ from the start point S. The trajectory Pt ′ is gradually corrected until it reaches the end, and the positional deviation of the end point E ′ is corrected without impairing the characteristics of the trajectory Pt before correction by a rapid trajectory change such as performing a correction operation at the start or end of conveyance. It becomes possible.

Further, in the present embodiment, the preset transport trajectory Pt is configured by a plurality of points P ₁ to _N including the start point S and the end point E, and the trajectory correction unit 33 includes each point constituting the transport trajectory Pt. since the P _{1 to N} perform enlargement or reduction of uncorrected distance d1 _k by moving along the displacement direction G, it is possible to realize a simple calculation to correct the conveyor track Pt.

In addition, in this embodiment, when transporting the transport target W using the articulated robot type transport mechanism 2 in which a plurality of links 21 to 23 are refractably connected, the transport trajectory Pt constitutes an articulated robot. The links 21 to 23 are represented by the angles θ _Ak · θ _Bk · θ _Ck , and the trajectory correction unit 33 sets the angles θ _Ak · θ _Bk · θ _Ck of the links indicating the transport trajectory Pt to the distance before correction. Since d1 _k is corrected in the direction of expansion or reduction along the deviation direction G, the conveyance path Pt is a complicated conveyance mechanism represented by the angles θ _Ak , θ _Bk , θ _Ck of the links 21 to 23. However, the trajectory can be corrected with a simple process.

  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 this embodiment, the trajectory is corrected so that the preset end point E of the transport trajectory Pt becomes the target end point E ′. However, as shown in FIG. 6, the start point S of the transport trajectory Pt is the target. Orbit correction may be performed so as to be the starting point S ′. Also in this case, as described above, it calculates the ratio of the corrected distance _{d2 1 (d2 1 / d1 1} ) for uncorrected distance d1 _1. Then, the pre-correction distance d1 _k of the shift direction component is calculated from the distance from the point P _k to the end point E, and the corrected distance d2 _k is calculated by multiplying the distance d1 _k by the ratio (d2 ₁ / d1 ₁ ). and the distance deviation direction component of the distance from the point P _k to the end point E moves the point P _k such that the corrected distance d2 _k along the shift direction G. In this way, it is possible to correct the positional deviation of the starting point S while achieving the same effect as described above.

  In addition, the trajectory correction described above is applied to a transfer device that uses a robot arm type transfer mechanism 2 in which a plurality of links are rotatably connected in series, but other transfer mechanisms 2 are used. It can also be applied to a transfer device. 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, each function unit illustrated in FIG. 1 is realized by executing a predetermined program by a processor, but each function unit may be configured by a dedicated circuit.

  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.

21, 22, 23 ... link 33 ... trajectory correction unit S ... start point S '... target start point E ... end point E' ... target end point Pt ... transport trajectory Pt 'before correction ... transport trajectory W after correction ... transport object G ... Misalignment direction P _k ... a certain point P ' _k ... corresponding point d1 _k ... pre-correction distance d2 _k ... post-correction distance θ _Ak · θ _Bk · θ _Ck ... link angle

Claims (4)

A transport device that transports a transport object along a transport path from a start point to an end point,
When carrying out transfer control using a preset transfer track, if the target end point is displaced from the end point of the transfer track, the transfer track is corrected so that the end point of the transfer track becomes the target end point. It has a trajectory correction unit,
The trajectory correction unit defines the direction connecting the uncorrected end point and the corrected target end point as the shift direction, and the distance of the shift direction component of the distance from the start point on the track before correction to a certain point as the pre-correction distance. The distance of the deviation direction component of the distance from the start point on the corrected trajectory to the corresponding point, with the point on the axis along the deviation direction passing through the certain point among the points on the corrected trajectory as the corresponding point Is the corrected distance with reference to the start point so that the ratio of the uncorrected distance and the corrected distance is the same regardless of the predetermined point on the trajectory. A transport apparatus that corrects the trajectory by enlarging or reducing the distance along a deviation direction. A transport device that transports a transport object along a transport path from a start point to an end point,
When carrying out transfer control using a preset transfer track, the transfer track is corrected so that the start point of the transfer track becomes the target start point when the target start point is displaced from the start point of the transfer track. It has a trajectory correction unit,
The trajectory correction unit defines the direction connecting the start point before correction and the target start point after correction as the shift direction, and sets the distance in the shift direction component of the distance from the point to the end point on the track before correction as the pre-correction distance. The distance of the deviation direction component of the distance from the corresponding point on the corrected trajectory to the end point is a point located on the axis along the deviation direction passing through the certain point among the points on the corrected trajectory. Is the corrected distance with reference to the end point so that the ratio of the pre-correction distance and the corrected distance is the same regardless of any given point on the trajectory. A transport apparatus that corrects the trajectory by enlarging or reducing the distance along a deviation direction. The preset transport trajectory is composed of a plurality of points including a start point and an end point,
The transport apparatus according to claim 1, wherein the trajectory correction unit expands or reduces the pre-correction distance by moving each point constituting the transport trajectory along the shift direction. A transport device that transports the transport object using a multi-joint robot-type transport mechanism in which a plurality of links are refractorably connected,
The transport trajectory is represented by the angle of each link constituting the articulated robot,
The transport device according to claim 1, wherein the trajectory correction unit corrects an angle of each link indicating the transport trajectory in a direction in which the pre-correction distance is expanded or contracted along a shift direction.

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