JP3980144B2 - XYθ table - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to XYθ table, in particular, regarding the movable platen via a thrust bearing on the fixed plate in the X direction and the XYθ table movable in a Y direction and the rotational direction.
[0002]
[Prior art]
The XYθ table is used when alignment is required in a printed circuit board manufacturing / inspection apparatus or a liquid crystal / PDP flat panel display manufacturing / inspection apparatus.
[0003]
In the XYθ table, a movable plate is provided on a fixed plate via a thrust bearing, and the movable plate can execute the operation of XYθ by controlling the amount of movement of the triaxial actuator. Conversely, in a state where the three axes cannot be controlled, the position of the movable plate is accompanied by an unexpectedly large movement.
[0004]
For example, assuming that the center of the movable plate is to be moved, if there is no θ operation at (X, Y) = (± 5 mm, ± 5 mm), the three-axis actuators only need to have a stroke of ± 5 mm. However, if it is desired to swing θ by 3 ° at the end of the X and Y strokes such as (X, Y, θ) = (± 5, ± 5, ± 3 °), the actuator is added to ± 5 mm, and A stroke for producing 3 ° is required. If the stroke of the actuator is ± 9 mm, assuming that an operation of (± 5, ± 5, ± 3 °) is possible, each of the three axes will move within the entire range of ± 9 mm when returning to the origin. Depending on the combination, the movable plate may swing at an angle of ± 5 ° or more, and interference may occur if a margin is not taken into consideration around the movable plate.
[0005]
[Problems to be solved by the invention]
In the XYθ table in which the movable plate is moved or rotated in parallel by driving the three-axis actuator described above, if the internal coordinates of the controller that performs control and the movement coordinates of the XYθ table do not match, that is, the movement of the three-axis actuator If the amount is arbitrarily combined within the stroke, it will move more than the required XYθ stroke. Therefore, if the controller does not know the current position of the actuator and returns to the home position for each of the three axes, or two or three axes at the same time, interference inside the table or parts or devices attached around the table There is a risk of collision.
[0006]
Each axis without coordinated operation, for example, when it is necessary to avoid unnecessary movements due to dimensional constraints or to prevent interference, or when it is necessary to take a configuration where the origin sensor output state cannot be determined for each axis actuator. Each homing algorithm had a problem.
[0007]
Another object of the present invention is to provide a interference accurately and XYθ table capable of returning to the mechanical origin of the movable plate in a short time without affecting the like.
[0008]
[Means for Solving the Problems]
The XYθ table according to the invention, X-direction movable plate on the fixed plate via a thrust bearing, a XYθ table provided to be movable in Y direction and rotational direction, U shaft connected to the movable platen , First to third actuators for moving the V-axis and W-axis, respectively, first to third sensors for detecting that the U-axis, V-axis and W-axis have reached the origin , respectively, U-axis, Fourth to sixth sensors for detecting that the V-axis and the W-axis have reached the limit of the movable range, a seventh sensor for detecting that the movable plate has reached the limit of the movable range, and the first Control means for controlling the first to third actuators based on the detection result of the seventh sensor . In response to the origin return command, the control means moves the U axis until the U axis reaches the origin or the limit of the movable range, or until the movable platen reaches the limit of the movable range; A second step of moving the V-axis and the W-axis in the same direction until the V-axis or W-axis reaches the origin or the limit of the movable range, or until the movable plate reaches the limit of the movable range; Is moved forward until the limit of the movement range is reached and the forward end of the U-axis is stored, and the U-axis is moved backward until it reaches the limit of the movement range, and the backward end of the U-axis is stored. Calculate the position to stop the axis, calculate the third step to move the U axis to the calculated position, and the direction to rotate the movable platen based on the detection results of the first to seventh sensors, and calculate V so that the movable plate rotates in the direction Or W-axis reaches the limit of origin or moving range, and a fourth step of moving the W-axis in the other direction together with the movable plate moves in one direction the V-axis until it reaches the limit of the movable range it characterized in that the movable platen is performed until return to the origin position.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an external perspective view of an XYθ table to which the present invention is applied, and FIG. 2 is a plan view of the same.
[0010]
1 and 2, a movable platen (stage) 2 is supported on a fixed platen (base) 1 by a thrust bearing (not shown), and the movable platen 2 is in the X direction, the Y direction, and the θ direction (rotation direction). ) Can be moved in three axes. This movement is performed by three electric linear actuators 3 to 5 and joints 6 to 8 such as linear guides.
[0011]
That is, three electric linear actuators 3, 4, 5 that extend and contract with each other in a plane including the movable platen 2 are attached to the side of the fixed platen 1. 7, 8 can be rotated in a plane, and is connected to the side of the movable platen 2 in a direction orthogonal to the expansion / contraction direction of the electric linear actuators 3, 4, 5. Stepping motors or servo motors are used for the electric linear actuators 3, 4, 5, and the movement of the electric linear actuators 3, 4, 5 is performed by controlling these motors. The electric linear actuator 3 controls the V axis, the electric linear actuator 4 controls the U axis, and the electric linear actuator 5 controls the W axis.
[0012]
The origin sensors 9, 10, 11 and the end limit sensors 12, 13, 14, 15, 16, 17 and the slide limit sensors 18, 19, 20, 21 correspond to the electric linear actuators 3, 4, 5 respectively. Is provided. The origin sensors 9, 10, and 11 detect that the electric linear actuators 3, 4, and 5 are at the origin, respectively, and the end limit sensors 12, 13, and 14 indicate that the electric linear actuators 3, 4, and 5 are at the forward end. The end limit sensors 15, 16, and 17 detect that the electric linear actuators 3, 4, and 5 are at the reverse end. The slide limit sensors 18, 19, 20, and 21 monitor the movement of the movable platen 2 in the X direction and the Y direction.
[0013]
FIG. 3 is a schematic block diagram of a control apparatus according to an embodiment of the present invention. The origin sensors 9 to 11, the end limit sensors 12 to 14, 15 to 17, and the slide limit sensors 18 to 21 shown in FIG. A memory 31 and a drive circuit 32 are connected to the CPU 30. The memory 31 stores the states of the origin sensors 9 to 11 and the limit sensors 12 to 21. The drive circuit 32 drives the electric linear actuators 3 to 5 in accordance with a command from the CPU 30.
[0014]
4 to 7 are flow charts for explaining specific operations of the embodiment of the present invention, and FIG. 8 is a view similarly showing the movement of the XYθ table.
[0015]
Next, with reference to FIGS. 1-8, the specific operation | movement of one Embodiment of this invention is demonstrated. When the movable platen 2 has returned to the origin, it is in the state shown in FIG. Now, as shown in FIG. 8B, the origin return operation is started from a state where θ is swung by −3 °. When the home position return command is input, it is determined in step SP1 in FIG. 4 (abbreviated as SP in the drawing) whether each limit sensor 12 to 21 is turned off, and in step SP2, each of the U, V, and W axes is determined. It is determined whether or not the origin sensors 9 to 11 are turned on.
[0016]
If it is not turned on, the process proceeds to step SP32 shown in FIG. 6, and the electric linear actuator 4 is driven to advance the U-axis as shown in FIG. 8B. In step SP33, it is determined whether or not the slide limit 18 or 20 is on, whether or not the U-axis end limit sensor 13 is turned on to be the forward end, or whether or not the U-axis origin sensor 10 is turned on. The U-axis advances until it is turned on. For example, if the end limit sensor 13 is turned on, it is determined in step SP34 whether the U-axis origin sensor 10 is turned on.
[0017]
In this case, since the origin sensor 10 is not turned on, the U-axis electric linear actuator 4 is driven and retracted in step SP35. In step SP36, it is determined whether or not the slide limit 19 or 21 is on, or whether or not the U-axis end limit sensor 18 is on and the reverse end, or whether or not the U-axis origin sensor 10 is on. If not, the U-axis is moved backward again at step SP35. For example, if the slide limit sensor 21 is turned on in step SP36, it is determined whether or not the U-axis origin sensor 10 is turned on in step SP37. Since it is not turned on here, the process proceeds to step SP8 shown in FIG.
[0018]
In step SP8, the V and W axis actuators 3 and 5 are driven to advance the V and W axes. In step SP9, the sensor to be managed is determined. If the sensor is not turned on, the V and W axes are advanced again. When it is detected that the W-axis end limit sensor 14 is turned on, it is determined in step SP10 whether or not the V-axis origin sensor 9 is turned on. It is determined whether or not it is turned on. Since this is also not turned on, all the limit sensors turned on in the steps so far are stored in the memory 31 in step SP12, and the process proceeds to step SP27 in FIG.
[0019]
In step SP27, the V and W axes are now retracted. In step SP28, the management target sensor is determined. If not, the V and W axes are retracted again. When the V-axis end sensor 15 is turned on, it is determined in step SP29 whether or not the V-axis origin sensor 9 is turned on, and since it is not turned on, it is determined whether or not the W-axis origin sensor 11 is turned on. . Since this is also not turned on, all limit sensors turned on in the steps so far are stored in the memory 31 in step SP31.
[0020]
With the above operation, it was determined that the origin sensors 10, 9, and 11 of the U, V, and W axes were not turned on.
[0021]
Next, in the state shown in FIG. 8C, the U-axis is advanced in step SP13 shown in FIG. 5, and it is determined in step SP14 whether the management target sensor is turned on. It is determined whether or not the axis origin sensor 10 is turned on. If the U-axis end limit sensor 13 is turned on, the U-axis advance end position is stored in the memory 31. Subsequently, as shown in FIG. 8D, the U-axis is retracted in step SP17, and it is determined in step SP18 whether the management target sensor is turned on. If turned on, the U-axis origin sensor 10 is turned on in step SP19. It is determined whether or not. If not, the slide limit sensor 21 is turned on, and the U-axis stop position is stored in the memory 31. As a result, the forward end position and the reverse end position or the slide limit position of each of the U, V, and W axes are stored in the memory 31.
[0022]
As described above, since the upper limit position and the lower limit position are stored in the X direction, the stop position of the U axis is calculated in step SP21, and the electric actuator 4 is driven in step SP22 to advance the U axis to the calculation position. As a result, the state shown in FIG.
[0023]
With respect to the Y direction, the sensor that is detected when the V and W axes are simultaneously moved forward and the sensor that is detected when the V and W axes are simultaneously moved back is stored in the memory 31. Therefore, in step SP50 shown in FIG. Calculate the direction in which In step SP51, it is determined whether or not the rotation direction is right. If the rotation direction is right, the operations of V-axis forward and W-axis backward obtained by calculation in step SP52 are performed as shown in FIG. By this operation, the θ angle of the movable platen 2 approaches 0 ° from −3 ° at the start.
[0024]
In step SP53, it is determined whether or not the management target sensor is turned on. If it is turned on, if it is detected in step SP54 that the V-axis origin sensor 9 is turned on, the process proceeds to step SP60. The W-axis retraction is repeated until the sensor 11 is turned on. When the V and W axis origin sensors 9 and 11 are turned on, the process returns to step SP32, and the U axis origin sensor 10 is detected by the U axis advance and the U axis retreat in step SP35.
[0025]
Finally, the process proceeds to step SP4, and when it is determined that the U, V, W axis origin sensors 10, 9, 11 are turned on, the origin return is completed.
[0026]
【The invention's effect】
As described above, according to the present invention, in response to the origin return command, the U axis is moved until the U axis reaches the origin or the limit of the movable range or the movable platen reaches the limit of the movable range. And a second step of moving the V-axis and the W-axis in the same direction until the V-axis or W-axis reaches the origin or the limit of the movable range, or until the movable plate reaches the limit of the movable range. And the U-axis is moved forward until it reaches the limit of the moving range and the U-axis forward end is stored, and the U-axis is moved backward until it reaches the limit of the moving range, and the U-axis backward end is stored. Based on the stored result, the position where the U axis should be stopped is calculated, the third step of moving the U axis to the calculated position, and the movable platen should be rotated based on the detection results of the first to seventh sensors. The direction is calculated and the movable board rotates in the calculated direction. As described above, the V-axis is moved in one direction and the W-axis is moved in the other direction until the V-axis or W-axis reaches the origin or the limit of the moving range, or the movable platen reaches the limit of the movable range. and a fourth step the movable platen is performed until return to the origin position. Therefore , the movable platen can be returned to the mechanical origin accurately and in a short time without being affected by interference.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an XYθ table to which the present invention is applied.
FIG. 2 is a plan view of an XYθ table.
FIG. 3 is a schematic block diagram of a control device according to an embodiment of the present invention.
FIG. 4 is a flowchart for explaining the operation of the embodiment of the present invention.
FIG. 5 is a flowchart showing the same procedure.
FIG. 6 is a flowchart showing the same.
FIG. 7 is a view showing a flowchart.
FIG. 8 is a diagram showing the movement of an XYθ table in one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed board 2 Movable board 3, 4, 5 Electric linear actuator 6, 7, 8 Joint 9, 10, 11 Origin sensor 12-17 End limit sensor 18-21 Slide limit sensor 30 CPU
31 Memory 32 Drive circuit

Claims (1)

X-direction movable plate on the fixed plate via a thrust bearing, a XYθ table provided to be movable in Y direction and the rotation direction,
First to third actuators that respectively move the U, V, and W axes connected to the movable platen, and a first that detects that the U, V, and W axes have reached the origin, respectively . Third sensor, fourth to sixth sensors for detecting that the U axis, the V axis, and the W axis have reached the limit of the movable range, respectively, and the limit of the movable range of the movable platen comprising a seventh sensor for detecting, and control means for controlling said first to third actuator based on a detection result of the first to seventh sensors that it has reached,
In response to the origin return command, the control means
A first step of moving the U-axis until the U-axis reaches the origin or the limit of the movable range, or until the movable plate reaches the limit of the movable range;
Second step of moving the V-axis and the W-axis in the same direction until the V-axis or the W-axis reaches the origin or the limit of the movable range, or until the movable plate reaches the limit of the movable range. When,
Advance the U-axis until it reaches the limit of the movement range and store the forward end of the U-axis and move the U-axis backward until it reaches the limit of the movement range to store the backward end of the U-axis; A third step of calculating a position where the U-axis should be stopped based on the stored result, and moving the U-axis to the calculated position;
Based on the detection results of the first to seventh sensors, the direction in which the movable platen should be rotated is calculated, and the V-axis or the W-axis is moved to the origin or moved so that the movable plate rotates in the calculated direction. The movable platen performs a fourth step of moving the V-axis in one direction and moving the W-axis in the other direction until the limit of the range is reached or until the movable platen reaches the limit of the movable range. characterized that you run to return to the original position, XY.theta. table.

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