JP2010247238A - Parallel link stage and optical element measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the rotation range of a movable member along the parallel direction of a parallel link mechanism in a parallel link stage and an optical element measuring instrument, and to form an open space at the center of a region surrounded by the movable member and the parallel link mechanism. <P>SOLUTION: The parallel link stage 1 is provided with: a turntable 2 supported rotatably around a rotation axis C; a motor 10 for rotating the turntable 2 around the rotation axis C; the movable member 3 spaced from the turntable 2; the parallel link mechanism 4 which connects the turntable 2 and the movable member 3 at least at three points spaced in circumferential direction in such a manner as to surround the rotation axis C between the turntable 2 and the movable member 3 to change each connection distance of the movable member 3 to the turntable 2; and a control unit 50 which controls the position and attitude of the movable member 3 by making motion control over the parallel link mechanism 4 and the motor 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a parallel link stage and an optical element measuring apparatus.

A parallel link mechanism in which a base and a movable member (end effector) are connected in parallel by a plurality of drive shafts is configured to extend and contract a plurality of linear drive shafts to control the position and posture of the movable member. The Stewart platform type is widely known. Of these, those having six drive shafts in the circumferential direction of the base and the movable member are capable of relative motion with a total of six degrees of freedom, including three degrees of freedom of translation and three degrees of freedom of rotation. Such a parallel link mechanism is used as a parallel link stage in which a work and a measured object are arranged on a movable member and the position and posture of the work and the measured object with respect to a base are controlled. It is also known that a parallel link mechanism is configured by using a fixed-length link instead of the drive shaft and rotating or connecting the link connecting portion with an actuator.
The parallel link stage having such a configuration has high rigidity and high-precision positioning as compared with a serial link mechanism such as an articulated robot, but has a narrow movable range. In particular, since the rotation range along the parallel direction of the parallel link mechanism is narrow, when trying to rotate the workpiece or the measured object held on the movable member around the normal of the movable member or the normal of the base There was a problem that a large rotation range could not be taken.
For this reason, conventionally, a parallel link stage has been proposed that can increase the rotation range of a movable member such as a workpiece held by the movable member or a measured object around the normal line or the normal line of the base.
As such a parallel link stage, for example, Patent Document 1 includes a roll axis rotation angle amplifier that amplifies the rotation angle around the roll axis by the parallel link mechanism, thereby increasing the rotation range around the roll axis. Drive devices have been proposed.
In Patent Document 2, an output flange (mounting portion) for mounting a movable member such as a tool or a table is rotatably arranged on a moving plate, and a servo motor serving as a drive device for rotating the output flange is provided. A parallel link mechanism has been proposed in which the degree of freedom of rotation is improved by integrating and deploying the movable plate.

JP 2004-353848 A JP 2000-130536 A

However, the conventional parallel link stage as described above has the following problems.
In the technique described in Patent Document 1, although the roll shaft rotation angle amplifier amplifies the rotation around the roll axis (around the normal of the base) by the parallel link to increase the rotation angle range, it still has one rotation. There is a problem that it is only a narrow rotation range of less than.
Further, since the rotation angle of the parallel link mechanism is amplified by the roll shaft rotation angle amplifier, the rotation error of the parallel link mechanism is also amplified. Therefore, there is a problem that the rotational accuracy around the roll axis is inferior to the rotational accuracy in other rotational directions.
Further, since it is necessary to provide a fixed link to be joined to the low-speed shaft of the roll shaft rotation angle amplifier, there is a problem that it is impossible to move in three degrees of translation.
In the technique described in Patent Document 2, since the servo motor is arranged on the moving plate and the output flange on the moving plate is rotated, the upper portion with the moving plate becomes heavy, and the actuator of the link that drives the moving plate The output must be taken large. Further, in order to prevent the servo motor arranged on the moving plate from interfering with the link or the like during the operation of the moving plate, a large space below the moving plate must be taken. Therefore, there is a problem that the apparatus becomes large as a whole.

  The present invention has been made in view of the above problems, and can improve the rotation range of the movable member along the parallel direction of the parallel link mechanism, and can also improve the region surrounded by the movable member and the parallel link mechanism. An object of the present invention is to provide a parallel link stage and an optical element measuring apparatus capable of forming an open space in the center.

  In order to solve the above-described problems, a parallel link stage of the present invention includes a turntable unit rotatably supported around a rotation axis, a rotation actuator unit that rotates the turntable unit around the rotation axis, and A movable member disposed at an interval with respect to the turntable portion, and at least three places with a space in the circumferential direction so as to surround the rotation axis between the turntable portion and the movable member. A parallel link mechanism that connects the movable member and the movable member, and changes the coupling distance of the movable member with respect to the rotary base at each coupling position, and by controlling the operation of the parallel link mechanism and the rotary actuator unit, A control unit that performs position control and posture control of the movable member.

  Moreover, in the parallel link stage of this invention, it is set as the structure by which the hollow hole part penetrated in the direction along the said rotating shaft line was provided in the area | region containing the said rotating shaft line of each of the said rotary base part and the said rotary actuator part. It is possible.

  In the parallel link stage of the present invention, the rotary link is mounted on the rotary base and the rotary actuator so as to be coaxial with the rotary axis, and the parallel link mechanism and the control are controlled when the rotary actuator is stationary and rotating. It is possible to provide a structure in which a rotary connector that electrically connects a rotating part is provided, and a hollow hole that penetrates in a direction along the rotational axis is provided in a region including the rotational axis of the rotary connector. is there.

  Moreover, in the parallel link stage provided with the hollow hole portion of the present invention, the movable member can be configured to have a through hole penetrating in the thickness direction at a position facing the hollow hole portion. is there.

  The optical element measuring apparatus of the present invention includes the parallel link stage, an optical element holding unit that is provided on the movable member and holds the optical element on the through hole of the movable member, and the rotary actuator unit side And a measurement unit that is disposed at a position facing the hollow hole and that measures the optical element through the hollow hole and the through hole of the movable member.

  According to the parallel link stage and the optical element measuring apparatus of the present invention, the parallel link mechanism and the movable member provided on the turntable unit can be rotated in the direction along the parallel direction of the parallel link mechanism by the rotary actuator unit. The rotation range of the movable member along the parallel direction of the parallel link mechanism can be improved, and an open space can be formed at the center of the region surrounded by the movable member and the parallel link mechanism.

It is a typical perspective view which shows the external appearance of the parallel link stage which concerns on the 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is a functional block diagram of the control part of the parallel link stage which concerns on the 1st Embodiment of this invention. It is typical sectional drawing of the parallel link stage and optical element measuring apparatus which concern on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A parallel link stage according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic perspective view showing an appearance of a parallel link stage according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a functional block diagram of the control unit of the parallel link stage according to the first embodiment of the present invention.

The parallel link stage 1 of the present embodiment is a stage that can hold a held body such as a measured body or a workpiece by adjusting the position and posture with high accuracy. The parallel link stage 1 can be used as a single stage, but can be used by being incorporated in a measuring device or an assembly device (not shown), for example.
In the following, for the sake of simplicity, the parallel link stage 1 is mounted on a horizontal plane constituted by the perforated base 70, holds a held body on the upper side of the parallel link stage 1, and uses a certain reference horizontal plane as a neutral position for holding. An example in the case of changing the position and orientation of the object to be held will be described. However, the parallel link stage 1 can be arranged in an orientation different from this, for example, in an arbitrary orientation such as a lateral orientation or a downward orientation, depending on the application.
As shown in FIGS. 1 and 2, the schematic configuration of the parallel link stage 1 includes a motor 10 (rotating actuator unit), a rotating table unit 2, a movable member 3, a parallel link mechanism 4, and a control unit 50 (control unit). ing.

  The motor 10 includes a fixed portion 20 having a fixed surface 20a for positioning the parallel link stage 1 in the height direction and fixing the parallel link stage 1 to the installation surface, and a rotation axis C that is disposed opposite the fixed portion 20 and orthogonal to the fixed surface 20a. Is a flat positioning motor that positions the rotation position of the rotation unit 21 around the rotation axis C with respect to the fixed unit 20. In this embodiment, a DD (direct drive) motor is employed.

As shown in FIG. 1, the fixed portion 20 is shaped like a plate having a substantially rectangular shape in plan view on the fixed surface 20a. As shown in FIG. 2, the fixed portion 20 has a concentric shape on the upper surface side (the opposite side to the fixed surface 20a). The inner peripheral cylindrical portion 20c and the outer peripheral cylindrical portion 20b are erected, and a hole penetrating in the axial direction is formed on the inner peripheral side of the inner peripheral cylindrical portion 20c. Further, in order to accommodate a scale 24 and an encoder 25, which will be described later, the fixed surface 20a is provided with a hole portion 20d that is coaxial with the inner peripheral cylindrical portion 20c and has a larger diameter than the inner peripheral cylindrical portion 20c and opens downward. It has been.
A plurality of stators, which are formed on the upper side of the fixed surface 20a and between the inner peripheral cylindrical portion 20c and the outer peripheral cylindrical portion 20b, are radially extended from the outer peripheral surface of the inner peripheral cylindrical portion 20c as a base end. A coil 22 is provided.
In addition, an encoder 25 that acquires absolute position information of the rotational position from the scale 24 is provided on the radial inner wall of the hole 20d. As the encoder 25, for example, an optical rotary encoder can be adopted.

The shape of the rotating portion 21 is an annular plate 21a having a mounting surface 21f formed of a donut-shaped plane in plan view on the upper surface side (opposite direction opposite to the fixed portion 20), and an inner edge portion of the annular plate. A cylindrical shaft portion 21b which is erected on the lower side (fixed portion 20 side) and has a cylindrical inner peripheral surface 21c penetrating in the axial direction on the inner peripheral side, and an annular plate 21a on the outer peripheral side surrounding the cylindrical shaft portion 21b. To a cylindrical shaft portion 21b, and an outer peripheral cylindrical portion 21e that is provided coaxially in the same direction.
The cylindrical shaft portion 21b has an outer diameter slightly smaller than the inner diameter of the inner peripheral cylindrical portion 20c of the fixed portion 20, and the inner ring of the two bearings 27 in which the outer ring is mounted on the inner peripheral portion of the inner peripheral cylindrical portion 20c. And is attached to the fixed portion 20 so as to be rotatable around the rotation axis C.
The outer cylindrical portion 21e has an outer diameter slightly smaller than the inner diameter of the outer cylindrical portion 20b, and is inserted into the inner ring of the bearing 27 in which the outer ring is inserted into the inner peripheral surface of the outer cylindrical portion 20b. 20 is attached to be rotatable around a rotation axis C.

In such an attachment state, the attachment surface 21 f of the rotating portion 21 can rotate around the rotation axis C while maintaining a parallel state with respect to the fixing surface 20 a of the fixing portion 20.
Further, in such an attached state, the tip end portion of the cylindrical shaft portion 21b protrudes into the hole portion 20d. A disc-shaped scale 24 on which a shape pattern for generating encoder pulses is formed is fitted on the outer periphery of the tip of the cylindrical shaft portion 21b in order to detect rotational position information by the encoder 25.
A magnet 23 is provided on the inner circumferential surface of the outer cylindrical portion 21e so as to face the tip of the stator coil 22 with a slight gap.
The opening of the hole 20d of the fixed portion 20 has a lid made of an annular plate having an inner diameter that is substantially the same as the inner diameter of the cylindrical shaft portion 21b, preferably slightly larger than the inner diameter of the cylindrical shaft portion 21b. The member 26 is fitted inside. Thereby, the encoder 25 and the scale 24 in the hole 20d and the tip surface of the cylindrical shaft portion 21b are covered from the fixed surface 20a side.
With such a configuration, the cylindrical inner peripheral surface 21 c and the inner peripheral surface of the lid member 26 constitute a hollow hole portion that penetrates in a direction along the rotation axis C in a region including the rotation axis C.

  The stator coil 22 and the encoder 25 of the motor 10 are electrically connected to the control unit 50 via a cable 55 including a power line, a signal line, and the like. Thereby, the motor 10 can receive power supply from the control unit 50 to the stator coil 22 and the encoder 25, receive a control signal for rotational position control, and transmit an encoder output signal representing the rotational position information to the control unit 50. It is like that.

As shown in FIG. 2, the turntable 2 is a donut-shaped perforated disk member having a through hole 2 c at the center and having the same outer diameter as that of the rotating part 21 of the motor 10.
The turntable 2 has a lower surface 2a overlaid on the mounting surface 21f of the rotating portion 21 of the motor 10 so that the center of the through hole 2c is substantially coaxial with the rotation axis C. It is fixed to the rotating part 21.
For this reason, the turntable part 2 is supported by the motor 10 so as to be rotatable around one rotation axis C. Further, the motor 10 constitutes a rotation actuator unit that rotates the turntable unit 2 around the rotation axis C.
Further, the through hole 2 c of the turntable portion 2 constitutes a hollow hole portion penetrating in a region along the rotation axis C in a region including the rotation axis C.

The movable member 3 is a member for holding the object to be held. In the present embodiment, the movable member 3 has a through-hole 3c at the center, and has a donut-like shape having an outer diameter smaller than the outer shape of the turntable 2 as a whole. It consists of a perforated disk-shaped member.
The upper side of the movable member 3 in the figure is a stage surface 3a that is a plane for holding the object to be held, and the link connecting surface 3b on the rear surface side (lower side) of the stage surface 3a is not particularly shown, but is not shown in the figure. An appropriate shape for attaching the parallel link mechanism 4 provided on the upper surface 2b is provided.
For this reason, the movable member 3 is supported above the turntable 2 with the parallel link mechanism 4 spaced from the turntable 2.
The size and shape of the through-hole 3c can be set to an appropriate size as long as the size and shape can hold the object to be held on the stage surface 3a. The through hole 3c of the present embodiment is formed by a highly accurate cylindrical surface orthogonal to the stage surface 3a, and the inner peripheral surface and the opening shape of the through hole 3c are also used as a reference for position detection and positioning of the movable member 3. Can be done.

The parallel link mechanism 4 connects the rotary base part 2 and the movable member 3 at six locations at intervals in the circumferential direction so as to surround the rotation axis C between the rotary base part 2 and the movable member 3. Thus, each connecting distance of the movable member 3 with respect to the turntable 2 is changed.
In the parallel link mechanism 4 of the present embodiment, as shown in FIG. 1, six sets of movable links 5 having the same configuration are arranged on the outer peripheral side position of the upper surface 2b of the turntable unit 2 and the link connecting surface of the movable member 3. It is connected to the outer peripheral side position of 3b.
The connecting positions of the movable links 5 in the movable member 3 are three sets of connecting positions adjacent to each other at equal distances in the circumferential direction on the circumference whose center coincides with the center of the through hole 3c. They are arranged in a positional relationship that divides the top into three equal parts.
Further, the connection position of the movable link 5 in the turntable 2 is determined by three connection positions adjacent to each other at equal distances in the circumferential direction on the circumference around the rotation axis C. They are arranged in a positional relationship that divides the top into three equal parts.
However, the distance between two connecting positions forming a set in the turntable 2 is set to be larger than the distance between two connecting positions forming a set in the movable member 3.

  In the present embodiment, the six connection positions on the turntable 2 are six positions that are substantially equally divided in the circumferential direction. With such an arrangement, the space required to connect each movable link 5 to the turntable unit 2 can be equally divided on the turntable unit 2, compared with the case where the connection positions are set at unequal intervals. Thus, the outer diameter of the turntable 2 can be reduced.

Each movable link 5 includes a link member 8 and a linear motion actuator 6.
The link member 8 is a rod-like member having a fixed length, one end of which is rotatably attached to the link connecting surface 3b of the movable member 3 via a movable side rotary joint 9b made of, for example, a spherical bearing or a universal joint. The other end side is fixed to the linear actuator 6 in a rotatable state via a fixed side rotating joint 9a such as a spherical bearing or a universal joint.
The movable side rotating joints 9b are attached so as to be close to each other in a pair at a connecting position on the outer peripheral side of the link connecting surface 3b so that these three sets form a 120 ° pitch in the circumferential direction.

The linear motion actuator 6 is inclined with respect to the rotation axis C from the rotary table 2 side toward the movable member 3 side at the other end of the link member 8 that is rotatably connected via the fixed side rotary joint 9a. This is a linear motion mechanism that moves along an oblique axis that forms an angle of, for example, 0 ° to 45 °.
The linear motion actuator 6 of the present embodiment includes, for example, a slider 7 provided so as to be linearly movable along a guide rail 6a attached to a triangular block-like support block 6b and extending along an oblique axis. For example, the structure driven by the ball screw feed mechanism not shown provided with a ball screw, a nut, a stepping motor, etc. is employ | adopted. Thereby, the other end part of the link member 8 can be linearly moved via the fixed side rotation joint 9a fixed to the slider 7 so that rotation is possible.

The linear motion actuator 6 having such a configuration is fixed in a positioned state at a connection position on the turntable 2 via the support block 6b.
For this reason, each movable link 5 is provided between the rotary table 2 and the movable member 3 in the circumferential direction so as to surround the through hole 2c of the rotary table 2, the through hole 3c of the movable member 3, and the rotation axis C. They are arranged at intervals. As a result, an open space is formed between the turntable 2 and the movable member 3 in the inner central portion surrounded by the six sets of movable links 5. Further, this open space penetrates the turntable 2 and the movable member 3 in the facing direction.

Further, the linear actuator 6 has a built-in encoder (not shown) that acquires position information of the slider 7.
Further, the linear actuator 6 is electrically connected to the control unit 50 via a cable 56, receives power supply from the control unit 50 and receives a control signal for operation control. An encoder output signal representing information can be transmitted to the control unit 50.

For example, when a three-phase stepping motor is used for the linear motion actuator 6, the cable 56 connected to each linear motion actuator 6 includes a covered cable including four power lines and seven signal lines.
Each of the cables 56 connected to each of the linear actuators 6 is inserted through the turntable 2 and the hollow hole of the motor 10 and drawn out of the apparatus. That is, as shown in FIG. 2, each cable 56 is distributed from the linear actuator 6 on the upper surface 2 b of the turntable 2 toward the center of the turntable 2, and the through hole 2 c of the turntable 2. And the inside of the cylindrical inner peripheral surface 21c of the motor 10, guided from the fixed surface 20a side of the motor 10 to the outside of the parallel link stage 1, and inserted through the hole of the perforated base 70, and then the control unit. 50.

The control unit 50 controls the operation of the parallel link mechanism 4 and the motor 10 according to an operation input via the operation unit 60 including an operation input unit such as a keyboard and an operation panel, for example, thereby fixing the motor 10 fixing unit. The position control and the posture control of the movable member 3 with respect to 20 are performed, and are electrically connected to the operation unit 60, each movable link 5 of the parallel link mechanism 4, and the motor 10.
As shown in FIG. 3, the functional configuration of the control unit 50 includes a drive amount analysis unit 51, a control data generation unit 52, a motor control unit 53, and a parallel link mechanism control unit 54.

The drive amount analysis unit 51 analyzes the operation input from the operation unit 60 and obtains the relative movement amount from the current position in order to place the movable member 3 at the position and posture according to the operation input.
For example, an imaginary intersection between the fixed surface 20a and the rotation axis C is defined as an origin O (see FIG. 2), the horizontal plane along the fixed surface 20a is the XY plane, and the rotation axis C orthogonal to the XY plane is the Z axis. Let the coordinate system be a fixed coordinate system. Then, with one point on the movable member 3, for example, a virtual intersection of the central axis of the through-hole 3c and the stage surface 3a as the origin P (see FIG. 2), the plane along the stage surface 3a is the xy plane, this xy An xyz coordinate system with the normal passing through the plane origin P as the z-axis is taken as a moving coordinate system. The rotation of the moving coordinate system with respect to the fixed coordinate system is expressed using rotation angles α, β, and γ about the X axis, the Y axis, and the Z axis of the fixed coordinate system.
In order to control the position and posture of the stage surface 3a from the current position to the position and posture corresponding to the operation input, the drive amount analysis unit 51 translates the translational movement component M in the fixed coordinate system of the origin P of the moving coordinate system relative to the current position. (ΔX, ΔY, ΔZ) and the rotational movement component R (Δα, Δβ, Δγ) of the moving coordinate system with respect to the fixed coordinate system can be calculated and sent to the control data generating unit 52.

Further, depending on the operation input from the operation unit 60, it may be necessary to temporally control the position and posture of the movable member 3 in the process of moving the movable member 3 to the target position and posture. For example, the held body on the movable member 3 may be swung at a predetermined cycle, or the held body on the movable member 3 may be rotated at a predetermined speed while maintaining a certain posture.
In such a case, the translational movement component M (ΔX, ΔY, ΔZ) and the rotational movement component R (Δα, Δβ, Δγ) are calculated as discrete time functions.

The control data generation unit 52 uses the translational movement component M (ΔX, ΔY, ΔZ) and the rotational movement component R (Δα, Δβ, Δγ) to change the connection distance L (ΔL ₁ ,..., ΔL) of the movable link 5. ₆ ) (hereinafter referred to as the link drive amount) is calculated, and the rotation amount Δφ of the motor 10 is obtained.
The calculation of the link driving amount L can be performed in the same manner as the control data of the parallel link mechanism having the six known movable links 5.
The link drive amount L (ΔL ₁ ,..., ΔL ₆ ) calculated by the control data generation unit 52 is sent to the parallel link mechanism control unit 54, and the rotation amount Δφ of the motor 10 is sent to the motor control unit 53. The

The motor control unit 53 performs control to change the rotation position of the motor 10 based on the control data of the rotation amount Δφ of the motor 10 sent from the control data generation unit 52. The motor control unit 53 controls the motor 10 via the cable 55. Electrically connected.
The parallel link mechanism control unit 54 is connected to the movable links 5 of the parallel link mechanism 4 based on the control data corresponding to the link drive amount L (ΔL ₁ ,..., ΔL ₆ ) sent from the control data generation unit 52. And is electrically connected to each movable link 5 via a cable 56.

  The device configuration of the control unit 50 may be configured only by hardware, or may be configured by appropriate hardware and a computer including a CPU, a memory, an input / output interface, an external storage device, and the like. These control functions may be realized by executing a control program on a computer.

Next, the operation of the parallel link stage 1 of this embodiment will be described.
First, the origin of the parallel link stage 1 is determined using an appropriate positioning jig or measuring machine. For example, as shown in FIG. 2, the fixed surface 20a and the stage surface 3a are parallel, and the origin P of the moving coordinate system is movable on the rotation axis C to a position that is a fixed distance H ₀ from the origin O of the fixed coordinate system. The position and posture of the member 3 are set. Hereinafter, this state is referred to as a reference position and a reference posture of the movable member 3.
The value of the encoder 25 of the motor 10 and the value of the encoder of the linear motion actuator 6 of each movable link 5 at the reference position and the reference posture are respectively set to the control unit 50 as a motor control unit 53 and a parallel link mechanism. It is stored in the control unit 54.
When an operation input for changing the position and orientation of the movable member 3 is input from the operation unit 60 after the origin is finished, the drive amount analysis unit 51 converts the translational movement component M (ΔX, ΔY, ΔZ) and the rotational movement component. R (Δα, Δβ, Δγ) is calculated and sent to the control data generation unit 52.

In the control data generation unit 52, the link drive amount L (ΔL ₁ ,..., ΔL ₆ ) and the motor 10 are determined from the translational movement component M (ΔX, ΔY, ΔZ) and the rotational movement component R (Δα, Δβ, Δγ). The rotation amount Δφ is calculated, the link drive amount L (ΔL ₁ ,..., ΔL ₆ ) is sent to the parallel link mechanism control unit 54 as parallel link control data, and the rotation amount Δφ of the motor 10 is used as the motor control data. The data is sent to the control unit 53.
As a result, the connection distance of each movable link 5 of the parallel link mechanism 4 and the rotational position of the motor 10 via the parallel link mechanism control unit 54 and the motor control unit 53 are determined by the link drive amount L (ΔL ₁ ,..., ΔL ₆ ) and the rotation amount Δφ are controlled simultaneously in parallel.

When the translational movement component M (ΔX, ΔY, ΔZ) and the rotational movement component R (Δα, Δβ, Δγ) are calculated as a function of discrete time, the parallel link mechanism 4 is provided for each time step. And the operation with the motor 10 are coordinately controlled, and the parallel link mechanism 4 moves with 5 degrees of freedom excluding the degree of freedom of rotation about the rotation axis C, and the motor 10 moves with the degree of freedom of rotation about the rotation axis C. The movement which draws a specific locus | trajectory is attained by the movement of 6 degrees of freedom by which these were combined.
The cable 56 connected to each movable link 5 is inserted through a hollow hole portion including a rotation axis C constituted by the through hole 2c, the cylindrical inner peripheral surface 21c, and the like. For this reason, by providing the cable 56 with an appropriate length in advance, the cable 56 is gently twisted according to the rotation angle of the movable member 3 so as not to hinder the rotation of the turntable 2. Can be.
Thus, in this embodiment, since the turntable 2 and the motor 10 have hollow holes, it is easy to distribute the cable 56 that connects the rotating system and the fixed system.

In order to rotate the movable member 3 around the rotation axis C, for example, one of the connecting links of the movable links 5 in which the movable side rotary joint 9b is close on the movable member 3 is extended and the other is reduced. Thus, it is possible to perform only by the parallel link mechanism 4 by shifting the circumferential position of each movable side rotating joint 9b with respect to the rotation axis C. However, in this case, the rotational movement range is limited by the limit of the amount of expansion / contraction of each movable link 5 and the limit for preventing interference between adjacent movable links 5.
For this reason, for example, it is quite difficult to rotate 360 ° or more with only the parallel link mechanism 4. For example, a rotation range of about ± 15 ° is a practical limit.
In the present embodiment, since the rotation about the rotation axis C is performed by the motor 10, the rotation range is not particularly limited as long as the twist of each cable 56 is allowable. If the cable 56 has about four power lines and about seven signal lines, about ± 2 to 3 rotations is easy, and ± 3 rotations or more are sufficiently possible.

As an example of movement control of the movable member 3 that is facilitated by cooperative control of the parallel link mechanism 4 and the motor 10 in the parallel link stage 1 of the present embodiment, the movable member 3 is tilted from the reference posture by a certain angle in a fixed coordinate system. The movement control for rotating the movable member 3 around the origin P can be given while maintaining the above.
In order to perform such movement control, the height in the direction along the rotation axis C of each point on the movable member 3 may be changed to a sine wave shape in a cycle synchronized with the rotation cycle of the motor 10.

  As described above, in this embodiment, the control unit 50 controls the operation of the parallel link mechanism 4 and the motor 10 to rotate the movable member 3 in the degree of freedom of movement, the movement range, and the movement accuracy of the parallel link mechanism 4. While being able to move relative to the base part 2, the rotary base part 2 can be rotated around the rotation axis C within the rotation range of the motor 10.

Further, in the present embodiment, the movable member 3 can be rotated a plurality of times around the rotation axis C without providing a rotary motor or the like, so that the movable member 3 can be compared with a case where a rotary motor or the like is provided. 3 can be reduced in weight. Thereby, since the output of the parallel link mechanism 4 can also be reduced, the apparatus can be reduced in size as a whole. Further, since the space on the lower surface side of the movable member 3 can be saved, the apparatus can be miniaturized.
Further, as in the case where a rotary amplifier is provided on the movable member 3, the central portion of the region surrounded by the parallel link mechanism 4 between the movable member 3 and the rotary base 2 is not occupied by the rotary amplifier. An open space can be formed. Thereby, the apparatus structure between the movable member 3 and the turntable part 2 can be simplified. This open space can be used for observing the object to be held on the movable member 3 from below, or for observing the through hole 3c when the origin of the movable member 3 is set. Further, it can also be used as a space in which a positioning jig or the like is disposed when the origin of the movable member 3 is set.

  As described above, the parallel link stage 1 of the present embodiment causes the motor 10 to rotate the parallel link mechanism 4 provided on the turntable 2 in the direction along the parallel direction of the parallel link mechanism 4 (around the rotation axis C). Therefore, the rotation range of the movable member 3 supported by the parallel link mechanism 4 along the parallel direction of the parallel link mechanism 4 can be improved, and the center of the region surrounded by the movable member 3 and the parallel link mechanism 4 can be improved. An open space can be formed in the part.

[Second Embodiment]
A parallel link stage and an optical element measuring apparatus according to a second embodiment of the present invention will be described.
FIG. 4 is a schematic cross-sectional view of a parallel link stage and an optical element measuring apparatus according to the second embodiment of the present invention.

As shown in FIG. 4, the parallel link stage 1 </ b> A of this embodiment is obtained by adding a rotary connector 12 to the parallel link stage 1 of the first embodiment.
Moreover, the optical element measuring apparatus 100 of this embodiment is provided with the parallel link stage 1A, the optical element holding | maintenance part 17, and the optical measurement part 16 (measurement part).
Hereinafter, a description will be given centering on differences from the first embodiment.

The rotary connector 12 is a tubular member as a whole including the connector fixing portion 12b and the connector rotating portion 12a.
The connector fixing portion 12b is formed of a cylindrical member fixed to the fixing portion 20 by being inserted inside the cylindrical inner peripheral surface 21c and having an end portion fixed to the lid member 26.
A plurality of wires (not shown) whose one ends are connected to contacts (not shown) provided on the inner peripheral side of the cylinder are provided inside the connector fixing portion 12b. The other ends of these wires are respectively connected to the fixed connector portion 12e at the outer peripheral portion of the connector fixing portion 12b protruding from the lid member 26 to the outside of the motor 10.

The connector rotating portion 12a is a cylindrical member that is rotatably connected to the connector rotating portion 12a while being inserted into the inner peripheral portion of the connector fixing portion 12b, and has a hollow hole portion 12d formed along the rotation center axis. .
An end portion of the connector rotating portion 12a opposite to that inserted into the connector fixing portion 12b is fixed to the fixing portion 20 while being fitted into the inner peripheral cylindrical portion 20c of the fixing portion 20 of the motor 10. .
Inside the connector rotating portion 12a, there are a plurality of contacts (not shown) that maintain electrical contact with each contact of the connector fixing portion 12b when stationary and rotating, and a plurality of wires (one end connected to these contacts) (Not shown) is provided. The other end sides of these wires are respectively connected to the rotation-side connector portion 12c provided on the circumference surrounding the hollow hole portion 12d on the outer peripheral side on the end surface in the axial direction on the rotation portion 21 side.

Cables 58 electrically connected to the respective linear motion actuators 6 of the parallel link mechanism 4 are coupled to the rotation side connector portion 12c. For this reason, each cable 58 is distributed along the radial direction of the turntable 2 from each linear actuator 6 toward the rotation-side connector 12c. Thereby, each cable 58 is arranged on the upper surface 2b of the turntable part 2 without traversing on the hollow hole part 12d.
Further, a cable 59 that is electrically connected to the parallel link mechanism control unit 54 (see FIG. 3) of the control unit 50 is coupled to the fixed-side connector unit 12e.

With such a configuration, in the parallel link stage 1 </ b> A, each linear motion actuator 6 controls the parallel link mechanism via the cable 58, the rotary connector 12, and the cable 59 when the rotating unit 21 is stationary or rotating. The unit 54 is electrically connected.
Further, the hollow hole portion 12 d of the rotary connector 12 is penetrated in a direction along the rotation axis C in a region including the rotation axis C.

The optical element holding unit 17 is, for example, a holding unit 17a that positions and holds the outer peripheral portion of the optical element W including a lens, a parallel plate, a prism, a mirror, and the like as a measurement target of the optical element measuring apparatus 100. It is a cylindrical or annular member as a whole including a through hole 17b that forms an opening facing the inner peripheral portion of the optical element W held by the portion 17a.
The optical element holding unit 17 is positioned and fixed so that the through hole 17b is positioned on the through hole 3c in a state where the fixed surface 17c parallel to the holding unit 17a is in contact with the stage surface 3a of the movable member 3. Has been. In the present embodiment, the through hole 17b has an inner diameter larger than the effective diameter of the optical element W, and the through hole 3c has an inner diameter larger than the through hole 17b. Thereby, the entire effective area of the optical element W can be observed from the lower side of the movable member 3.

The optical measurement unit 16 is disposed at a position facing the hollow hole 12d from below the parallel link stage 1 (on the motor 10 side), and is placed on the optical element holding unit 17 through the hollow hole 12d and the through hole 3c of the movable member 3. Measurement of the held optical element W is performed.
As long as the optical measuring unit 16 can measure the optical element W through the hollow hole 12d and the through hole 3c, an appropriate measuring machine can be adopted. Examples of a measuring machine suitable for the optical measuring unit 16 include measuring machines such as an MTF measuring machine, an interferometer, an eccentricity measuring machine, and a reflectance measuring machine. In these measuring machines, since the measuring light can be transmitted and received through the open space formed in the central part between the hollow hole 12d and the through hole 3c, the optical element W can be measured.
In the present embodiment, the arrangement position of the optical measurement unit 16 is set so that the measurement reference axis of the optical measurement unit 16 is coaxial with the rotation axis C.

Next, the operation of the optical element measuring apparatus 100 of the present embodiment will be described focusing on the operation of the parallel link stage 1A.
In the optical element measuring apparatus 100, the optical element holding unit 17 holds the optical element W, and the parallel element 1A is used to move the optical element W to a position and posture for starting measurement of the optical element W. The operation control of the parallel link stage 1A is the same as that of the parallel link stage 1 of the first embodiment.
For example, when the optical element W is a lens or the like, the movable member 3 is moved by the parallel link stage 1A while observing the surface of the optical element W through the hollow hole 12d, the through hole 3c, and the through hole 17b by the optical measuring unit 16. Move. Thereby, the optical axis of the optical element W is made to coincide with the measurement reference axis of the optical measurement unit 16, decentered by a certain distance from the measurement reference axis, or the distance on the measurement reference axis to the optical measurement unit 16. Adjust the position and posture.
In this way, when the optical element W is arranged at the measurement start position, the optical element W is measured by the optical measurement unit 16.
At that time, the parallel link stage 1A can perform measurement while changing the position and posture of the movable member 3 as required, for example, by changing the measurement site.
Since the parallel link stage 1A includes the motor 10 and the rotation range around the rotation axis C is large, it is possible to perform measurement by rotating the optical element W several times around the optical axis.
Further, by cooperatively controlling the movement amount of the motor 10 and the parallel link mechanism 4, the optical element W is rotated around the rotation axis C while the optical axis of the optical element W is kept constant with respect to the fixed coordinate system. Can be controlled.

Further, since the parallel link stage 1A includes the rotary connector 12, even if the motor 10 rotates, the cable 58 connected to the rotary side connector portion 12c and the cable 59 connected to the fixed side connector portion 12e Relative rotation is absorbed by the rotation of the rotary connector 12.
For this reason, each cable 58 is rotated while maintaining the relative position on the turntable 2 with the rotation of the motor 10, and the cable 59 is not rotated even if the motor 10 rotates. Thereby, even if the motor 10 is rotated, the twist of the cable as in the parallel link stage 1 does not occur at all, and therefore the rotation range of the motor 10 is not limited.
Therefore, according to the parallel link stage 1 </ b> A, the optical measurement unit 16 can perform measurement by performing continuous rotation of the optical element W around the rotation axis C a desired number of times.

  In the description of the first embodiment, the movable member 3 of the parallel link stage 1 is provided with the through hole 3c, and is formed by the through hole 2c of the turntable 2 and the cylindrical inner peripheral surface 21c of the motor 10. The case where an open space communicating with the rotation axis C is formed by the hollow hole portion has been described as an example, but it is not necessary to observe or measure the held body on the movable member 3 from below. Alternatively, the configuration may be such that the through hole 3c is not provided.

  In the description of the second embodiment, the example in which the parallel link stage 1A is provided as the optical element measuring apparatus 100 has been described. However, the cable 56 is inserted so that the measurement by the optical measuring unit 16 is not hindered. If possible, the parallel link stage 1 may be adopted instead of the parallel link stage 1A. For example, the cable 56 may be disposed in a region close to the cylindrical inner peripheral surface 21c and an open space may be formed at the center of the cylindrical inner peripheral surface 21c.

In the above description, the rotational movement around the rotation axis is described as an example in which all rotation movement is performed by the rotation actuator. However, the amount of rotation movement around the rotation axis is appropriately determined between the rotation actuator and the parallel link mechanism. It may be divided.
For example, the parallel link mechanism may perform rotation less than a certain rotation amount or rotation less than the rotation resolution of the rotary actuator.

  Further, in the above description, the example in which the rotation actuator unit is configured by a flat DD motor has been described. However, the rotation actuator unit is, for example, a gear mechanism, a belt transmission mechanism, etc. You may comprise from the motor etc. which transmit a rotational force through this transmission mechanism.

  In the above description, the example of the configuration in which the turntable unit 2 is fixed to the rotating unit 21 of the motor 10 has been described. However, the movable link 5 is directly connected to the rotating unit 21 of the motor 10 and the rotating unit 21 is rotated. 21 may constitute a turntable.

  In the above description, the parallel link mechanism 4 is configured to change the connection distance between the turntable 2 and the movable member 3 by moving the fixed-length link member 8 with the linear motion actuator 6. As described in the example, the parallel link mechanism may be configured to change the connection distance between the turntable 2 and the movable member 3 by six sets of variable length links provided to be extendable.

  In the above description, an example in which the parallel link mechanism 4 has six sets of movable links 5 has been described. However, there may be at least three sets of movable links 5. Even in this case, the rotational movement about the rotation axis C can be performed by the motor 10, so that the position and orientation can be controlled in the same manner as described above.

  In the description of the second embodiment, the example in which the rotation axis of the rotary connector 12 and the rotation axis C are coaxial has been described. However, the rotation axis of the rotary connector 12 and the rotation axis C are substantially the same. It only needs to be coaxial. At that time, the connector rotating portion 12a of the rotating connector 12 is fixed to the rotating table 2 or the rotating portion 21 of the motor 10, and the connector fixing portion 12b of the rotating connector 12 fixes the fixing portion 20 of the motor 10 or the motor 10. It may be fixed to other structures such as the perforated base 70.

In the description of the second embodiment, the example in which the rotary connector 12 has the rotary connector portion 12c has been described. However, the rotary connector portion 12c is replaced with a soldering terminal, and the wiring of the cable 58 is soldered. A configuration may be adopted in which the terminals are soldered and joined.
The same applies to the fixed-side connector portion 12e.
The cable 56 may not be a multi-line covered cable, and the power line, the signal line, and the like may be divided into independent small-diameter cables. Moreover, it is good also as a cable bundle gently bundled with these small diameter cables.

  In addition, all the components described in the above embodiments can be implemented in appropriate combination within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1, 1A Parallel link stage 2c Through-hole 3 Movable member 3c Through-hole 4 Parallel link mechanism 5 Movable link 6 Direct acting actuator 8 Link member 10 Motor (rotation actuator part)
12 rotation connector 12d hollow hole part 16 optical measurement part 17 optical element holding part 17b through hole 21c cylindrical inner peripheral surface (hollow hole part)
25 Encoder 50 Control unit 51 Drive amount analysis unit 52 Control data generation unit 53 Motor control unit 54 Parallel link mechanism control unit 55, 56, 58, 59 Cable 60 Operation unit 100 Optical element measuring device C Rotating axis W Optical element

Claims (5)

A turntable unit rotatably supported around the rotation axis;
A rotation actuator for rotating the turntable about the rotation axis;
A movable member disposed at an interval with respect to the turntable unit;
The rotary base and the movable member are connected to each other at at least three positions with a circumferential interval between the rotary base and the movable member so as to surround the rotation axis. A parallel link mechanism for changing each connecting distance of the movable member with respect to
A parallel link stage comprising: a control unit that performs position control and posture control of the movable member by performing operation control of the parallel link mechanism and the rotary actuator unit. The parallel link stage according to claim 1,
The parallel link stage characterized by the hollow hole part which penetrates in the direction in alignment with the said rotation axis in the area | region containing the said rotation axis of each of the said rotation base part and the said rotation actuator part. The parallel link stage according to claim 1,
A rotary connector that is attached to the rotary base and the rotary actuator so as to be coaxial with the rotary axis, and electrically connects the parallel link mechanism and the controller when the rotary actuator is stationary and rotating. With
A parallel link stage characterized in that a hollow hole portion penetrating in a direction along the rotation axis is provided in a region including the rotation axis of the rotary connector. The parallel link stage according to claim 2 or 3,
The parallel link stage, wherein the movable member includes a through-hole penetrating in a thickness direction at a position facing the hollow hole portion. The parallel link stage according to claim 4,
An optical element holding unit provided on the movable member and holding an optical element on the through hole of the movable member;
A measuring unit that is disposed at a position facing the hollow hole part from the rotary actuator part side, and that measures the optical element through the hollow hole part and the through-hole of the movable member. Optical element measuring device.

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