JP4840599B2 - Work transfer device - Google Patents

Description

  The present invention relates to a robot that moves an arm horizontally and that is placed on a workpiece gripping device and transports the gripped workpiece, and in particular, a moment generated by a sudden stop of the arm can be suppressed to a moment that does not damage the robot body. The present invention relates to a work transfer device.

  In semiconductor manufacturing systems that process workpieces such as glass substrates for liquid crystals and semiconductor wafers, a processing unit is arranged for each processing step, and a series of treatments are performed on the substrate by sequentially transporting the substrate to these processing units. I try to give it. Although the transfer may be performed by a belt conveyor or the like, in many cases, there is a merit that it is possible to flexibly cope with changes in the layout of processing steps, etc., so a robot that operates according to a work program in which the position and procedure of the transfer work are set Has been done by.

The robot will be described. FIG. 4 is a perspective view of the workpiece transfer device. FIG. 5 is a top view of the robot. FIG. 6 is a side view of the robot.
The robot 101 has a structure in which columns 112 divided into a plurality of blocks are connected in order to cope with an increase in the number of stockers (not shown) that store workpieces. In this way, the robot 101 having a height corresponding to a high layer is formed by sequentially connecting the column blocks 115. In FIG. 4, four column blocks 115 are connected. Both end surfaces of each column block 115 have a fitting structure so that the column blocks 115 are connected to each other, and further have positioning holes (not shown) for accurately arranging a guide mechanism including a linear guide. It is assembled by adjusting using a positioning jig.
In addition, the robot 101 is rotatably connected by joint portions 103, 104, and 105, and transmits an upper arm 121 and a lower arm 102 that vertically move an arm 102 that transmits a rotational force from an arm shaft rotation driving source and performs a desired operation. Has two sets. Further, the hand unit 108 that holds the workpiece 109 by the upper and lower arms 121 and 102 is configured to be linearly movable in the direction of taking out and supplying the workpiece 109 indicated by an arrow X in the drawing. Further, as shown in FIG. 5, the relationship between the rotation center axes of the base joints 103 provided in the two arms 121 and 102 is such that the upper arm 121 has a relationship with respect to the base joints 103 of the lower arm 102. The proximal joint portion 123 is configured so as to be displaced in the moving direction (X-axis direction) of the hand portion 108.

  The upper and lower arms 121 and 102 are connected to the support member 110 via joint portions 123 and 103, and include a vertical movement mechanism 111 that moves the support member 110 up and down by a vertical movement axis drive source. 121 and 102 can be adjusted in the vertical direction (Z-axis direction). Further, the pedestal 113 of the vertical movement mechanism 111 is provided so as to be rotatable with respect to the base 114 by a turning drive source so that the robot 101 can be turned to change its direction. Here, the vertical movement mechanism 111 is arranged in the same direction as the movement direction of the hand unit 108 with respect to the column 112, and the support member 110 is moved in the vertical movement direction (Z axis) by the vertical movement mechanism 111 and the movement direction of the hand unit 108 ( It protrudes in a direction (Y axis) perpendicular to the (X axis) and is connected to the joint portions 123 and 103 at the base ends of the upper and lower arms 121 and 102. Further, the support member 110 connected to the lower arm 102 moves the hand part 108 in the moving direction (X as shown in FIG. 5 so as not to interfere with the pedestal 113 when the lower arm 102 is moved downward by the vertical movement mechanism 111. A shape offset to the shaft) is formed.

  The robot 101 is connected to the control device 133 via a robot cable 134, and is configured to supply electric power to each drive source so that the robot 101 operates. The control device 133 is connected to the teaching means 135 via the teaching means cable 136. The teaching unit 135 has a plurality of buttons, and outputs an instruction to the control device 133 via the teaching unit cable 136 by pressing each button. The control device 133 operates the robot 101 by outputting drive power to each drive source of the robot 101 via the robot cable 134 in accordance with an instruction from the teaching unit 135. The teaching unit 135 includes a display unit 137 and displays information based on an instruction transmitted from the control device 133 via the teaching unit cable 136. The display means 137 is a display such as an LCD or a lamp. The teaching means 135 may be a general-purpose computer or a personal computer, for example.

The teaching means 135 includes a teaching means emergency stop button (not shown), the control device 133 includes a control device emergency stop button (not shown) and an emergency stop signal input from the outside, and the control device 133 depresses any emergency stop button. When an operation or emergency stop signal is received, the drive power supplied to each drive source is cut off, the drive source is braked, and the operation of the robot 101 is stopped. The emergency stop button is pressed to make an emergency stop in order to prevent an accident in advance, for example, when the robot is about to collide with an interferer.

The lower arm 102 will be described. The proximal end of the upper arm 106 is connected to the support member 110 via a drive shaft, and constitutes a rotatable shoulder joint portion 103. This shoulder joint portion 103 becomes the joint portion 103 at the base end of the lower arm 102. Further, the other end of the upper arm 106 and the proximal end of the forearm 107 are connected via a drive shaft to constitute a rotatable elbow joint 104. Further, the other end of the forearm 107 and the hand part 108 are connected via a drive shaft to constitute a rotatable hand joint part 105.
The lower arm 102 rotates the shoulder joint portion 103, the elbow joint portion 104, and the hand joint portion 105 by an arm shaft rotation drive source (not shown), and moves the hand portion 108 in the workpiece take-out / supply direction. At this time, in the lower arm 102, due to the mechanism, the hand portion 108 faces in one direction, the extended position where the upper arm 106 and the forearm 107 are fully extended, and the contracted position where the upper arm 106 and the forearm 107 are folded. Expansion and contraction is performed so that the line moves linearly. The lower arm 102 is attached to the support member 110, outputs drive power from the control device 133 to a vertical movement axis drive source (not shown) via the robot cable 134, and moves by the vertical movement mechanism 111. Since the same applies to the upper arm 121, a description thereof will be omitted.
As described above, the upper and lower arms 121 and 102 provided in the robot 101 have a plurality of joint portions, that is, the robot 101 is configured as a horizontal articulated robot.

Here, two kinds of operation procedures in which the robot 101 places and holds a workpiece will be described. 7 and 8 show a state in which the upper arm 121 and the lower arm 102 are individually operated to take out the workpiece 109 installed in a stocker (not shown) when the robot shown in FIG. 4 is viewed in the arrow Y direction. Show. FIG. 7 shows the removal of the work 109 with the lower arm 102, and then FIG. 8 shows the removal of the work 109 with the upper arm 121.
Hereinafter, the operation of FIG. 7 will be described in order from (a) to (d). First, the hand 108 provided on the lower arm 102 is positioned by the up-and-down moving mechanism 111 so as to be slightly below the second workpiece 109 from the top (a). Subsequently, the lower arm 102 is extended to an appropriate position for placing and gripping the work 109 by an arm shaft rotation drive source (not shown) (b). Further, the vertical movement mechanism 111 causes the hand 108 provided on the lower arm 102 to place the work 109 and move up to a position where it does not interfere with the stocker when taking out the work. Further, the work 109 is placed with the hand 108. Hold (c). Next, the lower arm 102 is contracted by an arm shaft rotation drive source (not shown) to take a standby posture (d).

Next, the operation of FIG. 8 will be described in order from (a) to (d).
The hand 108 provided on the upper arm 121 is placed in the direction indicated by the arrow Z- in the drawing with respect to the workpiece 109 by the vertical movement mechanism 111 (a), and the workpiece 109 is placed on the upper arm 121 by an arm shaft rotation drive source (not shown). Extend to a position suitable for placement and gripping (b). Then, the vertical movement mechanism 111 moves the hand 108 provided on the upper arm 121 in the direction of the arrow Z + in the drawing until it contacts the work 109, and the work 109 is placed and gripped by the hand 108 (c). Finally, the upper arm 121 is contracted by an arm shaft rotation drive source (not shown), and a standby posture is taken so as not to interfere with a work other than the work 109 placed and gripped (d). Here, the manner in which the workpiece is placed and gripped has been described. Conversely, when the placed and gripped workpiece is placed on the stocker, the workpiece is placed in the order of (d) to (a) in the figure. This can be realized by operating in the reverse procedure of the gripping procedure.

FIG. 9 shows a state in which when the robot shown in FIG. 4 is viewed in the direction of the arrow Y in the figure, the upper arm and the lower arm are operated simultaneously to take out a work set in a stocker (not shown).
Hereinafter, the operation of FIG. 9 will be described in order from (a) to (d). First, the hand 108 provided on the upper arm 121 is placed in the direction indicated by the arrow Z- in FIG. In general, the interval between the plurality of workpieces 109 is not narrower than the interval between the hand 108 provided on the upper arm 121 and the hand 108 provided on the lower arm 102. The provided hand 108 is placed in the direction of arrow Z- in the drawing with respect to the work 109. Subsequently, the upper arm 121 and the lower arm 102 are extended to an appropriate position for placing and gripping the work 109 by an arm shaft rotation drive source (not shown) (b). Further, the vertical movement mechanism 111 causes the hand 108 provided on the upper arm 121 and the hand 108 provided on the lower arm 102 to move in the direction of the arrow Z + in FIG. Place and hold (c). Through the series of operations so far, the workpiece 109 can be placed and held on the hand 108 provided on the upper arm 121 and the hand 108 provided on the lower arm 102, respectively. Next, the upper arm 121 and the lower arm 102 are contracted by an arm shaft rotation drive source (not shown), and a standby posture is taken so as not to interfere with workpieces other than the placed and held workpieces 109 (d). Here, the manner in which the workpiece is placed and gripped has been described. Conversely, when the placed and gripped workpiece is placed on the stocker, the workpiece is placed in the order of (d) to (a) in the figure. This can be realized by operating in the reverse procedure of the gripping procedure.

The operation procedure shown in FIG. 7 is as follows: (a) in FIG. 7 moves up and down once, (b) in FIG. 7 extends the arm once, (c) in FIG. In d), the arm is contracted once, in FIG. 8, the vertical movement is once in middle (a), the arm is extended once in (b), and the vertical movement is once in (c). In FIG. 4D, the operation of contracting the arm is performed once.
As a result, the operation procedure shown in FIG. 7 and FIG. 8 requires four movements to move up and down, two movements to extend the arm, and two movements to contract the arm to grip or place two workpieces. .
On the other hand, the operation procedure shown in FIG. 9 is such that the vertical movement is once in (a), the arm is extended once in (b), and the vertical movement is once in (c). In the middle (d), the arm is contracted once.
As a result, in order to grasp or place two workpieces, the operation procedure shown in FIG. 9 requires two vertical movements, one arm extension operation, and one arm contraction operation.
As described above, if the robot holds or places the same number of workpieces out of two procedures for placing and holding the workpiece from the stocker or placing the workpiece on the stocker, FIG. 7 and FIG. The operation procedure shown in FIG. 9 clearly has fewer operation procedures and the conveyance efficiency is better than the operation procedure shown in FIG.

However, for example, when an instantaneous power failure state, a control device emergency stop button provided in the control device 133, or a teaching means emergency stop button provided in the teaching means 135 is pressed, the driving power supplied to each driving source is increased. In the case of a sudden stop due to the interruption, the operation procedure shown in FIG. 9 may generate a larger stress than the operation procedure shown in FIGS.
FIG. 10 shows the state of the moment applied when the upper arm is extended while suddenly stopping. In the figure, h1 indicates the height from the center of the base 114 to the center of gravity G1 of the upper arm. While the upper arm 121 is moving in the direction of the arrow X in the figure, the hand 108 and the upper arm 121 have kinetic energy based on their mass and speed. When suddenly stopped, a force F1 is generated at the center of gravity G1 of the upper arm 121 shown in the figure by the kinetic energy. Further, the generated force F1 is transmitted through the column 112, and a tilting moment N1 based on the formula (1) is applied to the center of the base 114.
N1 = F1 × h1 (1)
The column 112 and the support member 110 are stressed by the tilting moment N1. Furthermore, it goes without saying that a larger stress is generated by a larger tilting moment when the workpiece is held by the hand.

FIG. 11 shows the state of the moment applied when suddenly stopping while the upper arm and the lower arm are extended. In the figure, h1 indicates the height from the center of the base 114 to the center of gravity G1 of the upper arm 121. h2 indicates the height from the center of the base 114 to the center of gravity G2 of the lower arm 102. While the upper arm 121 is moving in the direction of arrow X in the figure, the hand 108 and the upper arm 121 provided in the upper arm 121 have kinetic energy based on their own mass and speed. Similarly, while the lower arm 102 is moving in the direction of the arrow X in the figure, the hand 108 and the lower arm 102 provided in the lower arm 102 have kinetic energy based on their own weight and speed. When suddenly stopped, the kinetic energy generates a force F1 at the center of gravity G1 of the upper arm 121 and a force F2 at the center of gravity G2 of the lower arm 102 shown in the drawing. Further, the generated force F1 and force F2 are transmitted through the column 112, and a tilting moment N2 based on the formula (2) is applied to the center of the base 114.
N2 = F1 × h1 + F2 × h2 (2)
From the equations (1) and (2), it is clear that the falling moment N2 is larger than the falling moment N1. Therefore, in the case of the sudden stop shown in FIG. 11, the column 112, the support member 110, and the like are bent with a greater stress than in the case of the sudden stop shown in FIG. Furthermore, it goes without saying that a larger stress is generated by a larger tilting moment when the workpiece is held by the hand.

For the above reasons, when the operation procedure shown in FIG. 9 is performed, it is necessary to provide a column, a support member, and the like having higher strength than when the operation procedure shown in FIGS. 7 and 8 is performed. However, in order to increase the strength of the column and supporting member, it is necessary to take measures such as making the column and supporting member thicker or making it with a stronger material, but the installation area of the robot increases. The manufacturing cost increases. On the other hand, it is possible to reduce the tilting moment by shortening the length while maintaining the strength of the column, but there is a disadvantage that the workpiece cannot be conveyed to the high-layer part of the stocker.
In recent years, demand for large-sized plasma displays and liquid crystal displays has increased, so that glass substrates for liquid crystals and substrates such as semiconductor wafers have become larger, and stockers have been added to increase production per factory area. Is getting higher. Along with this, the size and height of the robot have increased, and the above-mentioned tilting moment has increased accordingly. However, in order to increase productivity, it is indispensable to carry out the operation procedure shown in FIG.
In order to solve such problems, a method is disclosed in which after the drive power is cut off, torque control is performed using the energy stored in the capacitor provided in the drive unit as a backup power source, and the upper and lower arms are decelerated and stopped without suddenly stopping. (See Patent Document 1).
JP-A-4-152091 (page 5, FIG. 3)

The conventional emergency stop device described in Patent Document 1 is intended to stop after an emergency stop is applied. However, even if deceleration control is performed using the energy stored in the capacitor as a backup power supply, the emergency stop device cannot be sufficiently slowed down. Therefore, kinetic energy may not be suppressed. In such a case, if the regenerative resistor is short-circuited or the mechanical brake is activated while the speed is not sufficiently slowed down, sudden braking is applied as soon as that occurs, and a very large tilting moment occurs, damaging the column and support member. There is a risk.
The present invention has been made in view of such a problem, and in order to perform high-speed work conveyance, even if the upper arm and the lower arm are suddenly stopped during the simultaneous operation, the column or the support member is damaged. It is an object of the present invention to provide a robot control device that can be stopped without being performed.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 has an upper arm and a lower arm via a support member that moves up and down by a vertical movement mechanism on a column that is turnable by a turning drive source with respect to a base. The arm includes: a robot provided with an arm shaft rotation drive source that extends and contracts in the same horizontal direction; and a workpiece gripping device that grips or places a workpiece at the tip ; and the robot based on a preset work program. in the work conveying apparatus comprising a control unit for driving and controlling each of the arm shaft rotating drive source and the vertical movement axis drive source, the allowable operating speed of the arm at the uppermost position of the vertical movement position of the vertical movement mechanism and the uppermost set allowable operating speed of the arm in the down position in advance, fast stretch operation of the arm when the expansion and contraction of the arm by the driving of the arm shaft rotary driving source It is obtained by further comprising a speed control means for speed limit so as not to exceed the allowable operating speed of the arm determined based on the vertical movement position of the arm.
According to a second aspect of the present invention, an upper arm and a lower arm are provided via a support member that moves up and down by a vertical movement mechanism on a column that is turnable by a turning drive source with respect to a base. The arm includes: a robot provided with an arm shaft rotation drive source that extends and contracts in the same horizontal direction; and a workpiece gripping device that grips or places a workpiece at the tip ; and the robot based on a preset work program. in the work conveying apparatus comprising a control unit for driving and controlling each of the arm shaft rotating drive source and the vertical movement axis drive source, the allowable operating speed of the arm at the uppermost position of the vertical movement position of the vertical movement mechanism and the uppermost allowable operating speed of the arm is set in advance in the lower position, prior to the expansion and contraction of the arm by the driving of the arm shaft rotating drive source, it expands and contracts the arm And the allowable movement speed of the arm calculated based on the vertical movement position of the arm, and when the speed of the expansion / contraction movement of the arm exceeds the allowable movement speed of the arm, the movement of the robot is stopped. A control means is provided.
According to a third aspect of the present invention, the allowable operation speed of the arm obtained based on the vertical movement position of the arm is obtained by first obtaining the vertical ratio of the vertical movement position to the uppermost position of the vertical movement mechanism, and then presetting It is characterized in that it is obtained from the allowable operation speed of the arm at the highest position of the vertical movement position of the vertical movement mechanism, the allowable operation speed of the arm at the lowest position and the vertical ratio .
According to a fourth aspect of the present invention, a portion between the uppermost position and the lowermost position of the vertical movement position of the vertical movement mechanism is divided into a plurality of vertical position ranges, and an allowable operation speed in each vertical position range is preset. The allowable operation speed of the arm determined based on the vertical movement position of the arm is an allowable operation speed in the vertical position range including the vertical movement position of the vertical movement mechanism .

With the above configuration, the control device of the present invention considers the case of sudden stop during the simultaneous operation of the upper arm and the lower arm, and limits the expansion / contraction operation speed or stops the operation of the robot. It becomes possible to stop suddenly without damaging the components of the robot of the support member. For this reason, the speed of the work program can be set without worrying about the sudden stop impact applied to the column and the support member or the robot damage due to the moment .

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

A workpiece transfer apparatus that applies the present invention to a robot having a configuration shown in FIGS. 4, 5, and 6 and having a vertical movement mechanism will be described.
In the storage means (not shown) provided in the control device 133, the link length of the upper arm 106, the link length of the forearm 107, the reduction ratio of the speed reducer provided in the arm shaft rotation drive source of the upper and lower arms 121 and 102, Barycentric position, barycentric position of the forearm 107 from the joint part 104, barycentric position of the hand 108 from the joint part 105, barycentric position of the work 109 from the joint part 105, allowable arm operating speed, maximum vertical position, control Stores parameters such as method specification and operation cycle time.

The allowable arm operation speed stored in the storage means is the arm operation speed when the vertical movement mechanism is at the uppermost position and the arm operation speed when the lower movement mechanism is at the lowermost position.
When the vertical movement mechanism is at the uppermost position, the arm operating speed that the strength of each member can withstand as a result of simulating the stress generated in the column 112, the support member 110, etc. during the sudden stop during the arm expansion / contraction operation, or actually Although the robot 101 is in the uppermost position, the arm operating speed that can be withstood by each member obtained by testing the stress generated in the column 112, the support member 110, etc. during a sudden stop during the arm expansion / contraction operation. Even if the simulation and the test are not performed, it is only necessary that the operating speed of the arm can withstand the strength of each member in terms of dynamics when the vertical movement mechanism is at the uppermost position.
Similarly, the arm operating speed when the vertical movement mechanism is at the lowest position is the arm operating speed that the strength of each member can withstand.

  The control method designation stored in the storage means is that when the arm operation speed exceeds the allowable arm operation speed determined according to the vertical position of the vertical movement mechanism, the “speed control” In this method, the operation speed is reduced to control the operation speed so that the strength of each member can withstand.

Various parameters are input by pressing a button provided on the teaching unit 135 or stored in a storage unit of the control device 133 from an external storage device (not shown) via a communication unit.
Although other parameters are also required for the desired operation and control of the workpiece transfer device, the description is omitted because it is not related to the present invention.

  The robot 101 operates by giving an operation command to each drive source via the robot cable 134 in accordance with an operation program that is stored in advance in a storage unit and sets a procedure for operating the robot 101 and performing a transfer operation.

The operation of a robot composed of a plurality of axes to which the present invention is applied will be described with reference to the flowchart of FIG.
The operation program describes the command operation speed of each drive source, and the control device 133 determines the drive source for each control cycle (also called a calculation cycle) based on the current position, the operation target position, and the command operation speed. Find the target position. At this time, the operation speed of each drive source is determined by the distance to the target position and the control cycle.
In addition, there is a case where the command operation speed is not described in the operation program, but in such a case, since there is an implicit command operation speed such as operation at an operation speed stored in advance in the storage means, The operating speed of each drive source can be calculated.

  (Step 1) Based on the target position and command speed set in the operation program, an operation command (position command) to each drive source after one operation cycle is created.

  (Step 2) The position (Z) of the vertical movement axis after the operation command output to the vertical movement axis drive source obtained in Step 1 is obtained.

(Step 3) The vertical movement mechanism obtains the ratio of the vertical position to the uppermost position.
Here, when the uppermost position of the vertical movement mechanism is Z _H , the lowermost position is Z _L , and the current position or the vertical position after the output of the operation command in Step 2 is Z, the vertical ratio μ is obtained by Expression (3).
μ = (Z−Z _L ) / (Z _H −Z _L ) (3)

(Step 4) Next, the arm up and down movement mechanism that is allowed in the permissible speed V _L as well as from the upper and lower ratio mu, vertical position Z at a permissible speed V _H and a lowermost position Z _L when the uppermost Z _H Is obtained by the equation (4).
V = V _L − (V _L −V _H ) × μ (4)

  (Step 5) If the control method designation is speed control designation, the process branches to step 6. If not (speed control designation), the process branches to step 10. Here, the control method designation is not the setting stored in the storage means, but may be, for example, signal reception from an input means (not shown) provided in the control device 133. In this case, the control method designation is It becomes invalid.

(Step 6) (When Control Method Specification is Speed Control Specification) Based on the operation command of each drive source obtained in Step 1, the operation speed V _d of the upper arm 121 or the lower arm 102 of the robot 101 is obtained.
Here, for example, the arm shaft rotation drive source is a motor equipped with an absolute encoder. From the command operation speed based on the operation program, an operation command pulse value for one operation cycle is obtained, and the operation command pulse value is added to the encoder pulse value before operation, and the encoder pulse value after one operation cycle is obtained. Subsequently, the encoder pulse value after one operation cycle is converted into an angle by using the reduction ratio of the speed reducer provided in the arm shaft rotation drive source of the lower arm 102, and the angle and the link length of the upper arm 106 and the link length of the forearm 107 are converted. Using the kinematic equation from the joint 103 to the joint 105, the position of the joint 105 viewed from the joint 103 after one motion cycle is obtained. Similarly, the position of the joint portion of the upper arm 121 is obtained. Furthermore, the motion vector from the position before operation to the position after one operation period is calculated, the operation speed V _d of the arm is obtained by dividing the operating cycle time.
If the obtained arm operating speed V _d exceeds the allowable arm operating speed V obtained by the equation (4), the process branches to step 7, and if not, the process branches to step 9.

  (Step 7) The command speed is set to the permissible arm motion speed V obtained by the equation (4), and based on the target position set in the motion program, the motion command (position to each drive source after one motion cycle) Command). In other words, the operation speed set in the operation program is reduced and the reproduction is performed. This procedure does not exceed the allowable arm operating speed.

  (Step 8) In the process described above, the arm does not operate at the operation speed specified by the operation program, but operates at the limited operation speed. Therefore, the control device 133 sends a display signal to the teaching means 135 via the teaching means cable 136. The teaching unit 135 receives the display signal and displays on the display unit 137 that the speed is limited. The display method is realized by, for example, displaying a message to that effect on the display display or lighting a pilot lamp.

  (Step 9) The operation command obtained and held up to the previous step is output to each drive source.

(Step 10) (control method specification be a stop control specification) operating speed V _d of the arm by the same procedure as Step 6, it is determined whether more than the operating speed V of the arm is allowed. If the arm operating speed exceeds the allowable arm operating speed, the process branches to step 11; otherwise, the process branches to step 12.

  (Step 11) Since an attempt is made to operate at an arm operating speed that exceeds the allowable arm operating speed, the airframe may be damaged when suddenly stopped. Therefore, the operation of the robot 101 is stopped by a known means (deceleration stop, etc.), and the control device 133 sends a notification signal to the teaching means 135 via the teaching means cable 136. The teaching unit 135 receives the notification signal and notifies the display unit 137 that it cannot operate. As a notification method, for example, a message to that effect is displayed on a display, a pilot lamp is turned on, or a sound is emitted from a speaker.

  (Step 12) Since it is determined that it is not particularly necessary to control the operation speed of the arm or stop the operation of the robot, the operation command created in Step 1 is output to each drive source.

FIG. 2 illustrates the effect of the present invention. The vertical movement mechanism 111 is determined from the arm operating speed V _H allowed at the maximum upper position Z _H and the maximum upper position of the vertical movement mechanism 111 and the arm operating speed V _L allowed at the lowest position Z _L and the lowest position. The vertical position Z of the arm and the arm operating speed V allowed at that time have a linear relationship. As the vertical position increases, the allowable arm operation speed decreases, and as the vertical position decreases, the allowable arm operation speed increases. At the time of a sudden stop, a tilting moment based on the formula (1) is applied to the center of the base 114. Therefore, if the speed is the same, a larger tilting moment is applied as the vertical position increases. The force applied at the time of sudden stop is determined by the momentum of the hand provided with the arm, the gripped work, and the sudden stop acceleration. Since the acceleration of the sudden stop is determined by the characteristics of the mechanical brake, the viscous friction of each axis, and the like, it can be said that it is always constant except for the friction change due to the temperature change. In particular, in a semiconductor manufacturing system for processing a workpiece such as a liquid crystal glass substrate or a semiconductor wafer, the temperature of the manufacturing environment is kept constant, so that there is almost no change in friction due to temperature change. From the above, since the acceleration of the sudden stop is constant, the force which is the differential value can be controlled by changing the momentum temporarily.

As described above, the operation command output to each drive source through the process from Step 1 to Step 9 does not exceed the allowable arm operation speed, and as a result, sudden stop is performed during the operation of the arm. Even so, the stress generated in the column 112, the support member 110, and the like can withstand the strength of each member, and the airframe is not damaged. Moreover, since the allowable speeds at all the vertical positions are automatically determined by once determining the allowable speed at the maximum vertical position, it can be easily applied.
Further, when it is determined that the operation speed exceeds the allowable speed, the operation of the robot can be stopped.
The above is an example for carrying out the invention, and the arm may be a linear motion shaft composed of, for example, a motor, a rack and pinion, or a ball screw, or a linear motion shaft powered by air pressure or hydraulic pressure by electromagnetic valve control. The arm only needs to have a mechanism capable of linearly interpolating the workpiece in the X-axis direction.
The elevating shaft is a mechanism that can interpolate in the Z-axis direction with two links, a linear motion shaft composed of, for example, a rack and pinion, a linear motion shaft powered by air thickness or hydraulic pressure by solenoid valve control. May be.
The teaching means 135 may be a general-purpose computer or a personal computer, for example. Although the robot cable 134 and the teaching means cable 136 are shown as wired transmission means electrically connected, this may be, for example, wireless means using radio waves.

FIG. 3 shows another setting example of the relationship between the position of the vertical movement mechanism and the allowable operation speed of the arm. In the figure, the vertical axis represents the position of the vertical movement mechanism, where the highest position is Z _H and the lowest position is Z _L. The horizontal axis is permissible speed, allowable speed V _L when the vertical movement mechanism uppermost position Z _H, the allowable velocity V _L when the lowest position Z _L are the same as in Example 1, the vertical movement mechanism position, (4 divided in this embodiment) is divided between the uppermost position and the lowermost position, the allowable velocity V _H when the position of the vertical movement mechanism is Z _H, the position of the vertical movement mechanism is less than Z _H When the position is Z ₁ or more, the allowable speed V ₁ , when the position of the vertical movement mechanism is less than Z ₁ Z ₂ or more, the allowable speed V ₂ , and when the position of the vertical movement mechanism is less than Z _{2 and} Z ₃ or more, the allowable speed V ₃ , if the position of the vertical movement mechanism is more than Z ₃ below Z _L are those permissible speed V _L is set. The method for storing the setting is not limited, for example, using a table.
_However, a relationship of _{Z H> Z 1> Z 2} > Z 3> Z L, V L> V 3> V 2> V 1> V H.

When the arm operating speed V obtained in step 3 to step 4 of the first embodiment is obtained from the position of the vertical movement mechanism based on the above-described setting, the following is obtained.
When V = V _H Z is V _H V = V _{1 When} Z is less than Z _H Z ₁ or more V = V _{2 When} Z is less than Z ₁ Z ₂ or more V = V ₃ Z is less than Z ₂ Z ₃ or more In the case of V = V _L Z is less than Z _{3 and} is equal to or greater than Z _L Steps 6 and subsequent steps of the first embodiment are performed at the arm operating speed V thus obtained.

Flow chart of the present invention Relationship between vertical position and allowable arm operation speed Setting example of relationship between vertical movement mechanism position and allowable arm movement speed Perspective view of workpiece transfer device Top view of robot Robot side view Grasping the lower work of the stocker by operating the upper arm and lower arm individually Grasping the upper work of the stocker by operating the upper arm and lower arm individually Grasping workpiece of stocker by operating upper arm and lower arm simultaneously State of moment applied when suddenly stopping while extending upper arm State of moment applied when suddenly stopping while extending upper arm and lower arm

Explanation of symbols

101 Robot 102 Lower arm 103 Shoulder joint 104 Elbow joint 105 Hand joint 106 Upper arm 107 Forearm 108 Hand part 109 Work 110 Support member 111 Vertical movement mechanism 112 Column 113 Base 114 Base 115 Column block 121 Upper arm 133 Controller 134 Robot cable 135 Teaching means 136 Teaching means cable 137 Display means

Claims (4)

A column, which can be turned by a turning drive source with respect to the base, has an upper arm and a lower arm via a support member that moves up and down by a vertical movement mechanism, and each of the arms extends and contracts in the same horizontal direction. an arm shaft rotation drive source for a workpiece holding device for gripping or mounting the workpiece on the tip, and robots with an arm shaft rotation driving source and the said each of said robot based on a preset operation program In a work transfer device comprising a control device that drives and controls a vertical movement axis drive source,
The allowable operation speed of the arm at the uppermost position of the vertical movement position of the vertical movement mechanism and the allowable operation speed of the arm at the lowermost position are preset,
The speed at which the arm expands and contracts when the arm shaft rotational drive source is driven is a speed limit that does not exceed the allowable operating speed of the arm determined based on the vertical movement position of the arm. A work transfer device comprising a control means. A column, which can be turned by a turning drive source with respect to the base, has an upper arm and a lower arm via a support member that moves up and down by a vertical movement mechanism, and each of the arms extends and contracts in the same horizontal direction. an arm shaft rotation drive source for a workpiece holding device for gripping or mounting the workpiece on the tip, and robots with an arm shaft rotation driving source and the said each of said robot based on a preset operation program In a work transfer device comprising a control device that drives and controls a vertical movement axis drive source,
The allowable operation speed of the arm at the uppermost position of the vertical movement position of the vertical movement mechanism and the allowable operation speed of the arm at the lowermost position are preset,
Before the arm shaft rotation drive source is driven to expand and contract the arm, the arm is expanded and contracted, and the arm is allowed to move based on the vertical movement position of the arm.
A workpiece transfer device comprising: a stop control means for stopping and controlling the operation of the robot when the speed at which the arm expands and contracts exceeds an allowable operation speed of the arm. The allowable operation speed of the arm obtained based on the vertical movement position of the arm is obtained by first obtaining the vertical ratio of the vertical movement position of the vertical movement mechanism with respect to the uppermost position, and then the vertical movement of the vertical movement mechanism set in advance. 3. The workpiece transfer apparatus according to claim 1, wherein the workpiece transfer device is obtained from an allowable operation speed of the arm at the uppermost position, an allowable operation speed of the arm at the lowermost position, and the vertical ratio . Between the uppermost position and the lowermost position of the vertical movement position of the vertical movement mechanism is divided into a plurality of vertical position ranges, the allowable operation speed in each vertical position range is preset,
3. The allowable operation speed of the arm obtained based on the vertical movement position of the arm is an allowable operation speed in the vertical position range including the vertical movement position of the vertical movement mechanism. The workpiece transfer device described in 1.

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