JP2010029960A - Hybrid mechanism and machine tool with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid mechanism capable of reducing a cost and also reducing operation load of an operator. <P>SOLUTION: A control unit is provided, which converts an instruction value corresponding to a turning position and a movement position of a link head 301 given on an absolute coordinate system into an instruction value for a head driving mechanism 302, link driving mechanisms 304 and 305 (first driving mechanism) and a rail driving mechanism (second driving mechanism) based on a mechanism parameter for defining a structure of the entire mechanism containing a parallel mechanism 300 and a serial mechanism 400 and drives to control the first and second driving mechanisms. The control unit calculates driving amounts of the first and second driving mechanisms based on a specific calculation formula from the turning position and the movement position of the link head 301 when converting the instruction value corresponding to the turning position and the movement position of the link head 301 into the instruction value for the first and second driving mechanisms. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hybrid mechanism used as a driving force transmission mechanism when a tool (machining tool) for machining a workpiece (workpiece) is displaced, for example, and a machine tool including the same.

  As is well known, machine tools include a grinding machine, a lathe and a milling machine, and these various machine tools are selectively used according to the processing content.

  In such a machine tool, by moving a spindle head that supports a processing tool such as a grindstone or a cutting tool, a table that supports a workpiece, or the like to a desired position, or by rotating at a desired angle, Processing such as grinding and cutting is performed by relatively displacing the workpiece and the processing tool.

  In recent years, this type of machine tool is effective as a mechanism that achieves high rigidity, high accuracy, and high speed, and therefore, a machine having a parallel mechanism having a link in which the base to the link head are connected in parallel. A machine tool having a hybrid mechanism using both a parallel mechanism and a serial mechanism is also known.

  A conventional hybrid mechanism includes a parallel mechanism having first to third link means and a serial mechanism having a rotating shaft (Patent Document 1).

  In the parallel mechanism, one end of each of the first to third link means is connected to a fixed base via a control arm, and the other end is connected to a movable member so as to be swingable. Yes.

  The serial mechanism has a rotating shaft inserted through a movable member and is rotatably supported via a bearing. Further, the rotation shaft has one end portion connected to the motor on the fixed base via a telescopic transmission member and the other end portion connected to the work member.

  With the above configuration, when the control arm and the rotation shaft are driven and controlled, the work member can be rotated around the rotation axis and moved along an axis parallel to the rotation axis and on a plane orthogonal to the axis. It becomes.

  By the way, in this type of hybrid mechanism, the control arm and the rotating shaft are independently controlled.

Usually, the mechanism parameters that define the configuration of the hybrid mechanism do not necessarily match the design values. For this reason, in order to improve the position accuracy of the working member, it is important to correct the mechanism parameter and to drive and control the actuator (motor).
Japanese Examined Patent Publication No. 4-45310

  However, according to the conventional hybrid mechanism in which the parallel mechanism and the serial mechanism are controlled separately, the processing parameters and the assembly errors of each component are corrected by separately correcting the mechanism parameters that define the configurations of the parallel mechanism and the serial mechanism. Will be corrected. As a result, there has been a problem that the processing accuracy and assembly accuracy of each component become strict and the cost increases.

  Further, the correction of the mechanism parameter for each mechanism has a problem that the operation burden on the operator is increased accordingly.

  Therefore, the object of the present invention is to correct the mechanism parameters that define the configuration of the entire hybrid mechanism to correct machining errors and assembly errors of each component, thereby reducing costs. In addition, an object is to provide a hybrid mechanism that can reduce an operation burden on an operator and a machine tool including the same.

(1) In order to achieve the above object, the present invention rotates a processing tool for processing a workpiece and a link head supporting one of the workpieces around a first axis, and the first axis and A parallel mechanism that moves along a second axis that is orthogonal, a first drive mechanism that operates the parallel mechanism, and a third axis that intersects the second axis in a plane orthogonal to the first axis. A serial mechanism for moving the parallel mechanism, a second drive mechanism for operating the serial mechanism, and command values corresponding to the rotation position and movement position of the link head given in an absolute coordinate system, The first drive mechanism and the mechanism based on a mechanism parameter that defines the structure of the entire mechanism including the mechanism and the serial mechanism And a control unit that converts the command value to the drive mechanism and controls the drive of the first drive mechanism and the second drive mechanism, the control unit corresponding to the rotation position and the movement position of the link head. In converting the values into command values for the first drive mechanism and the second drive mechanism, the first drive mechanism and the second drive mechanism are based on a specific arithmetic expression from the rotation position and the movement position of the link head. A hybrid mechanism for calculating the driving amount of the motor is provided.

(2) In order to achieve the above object, the present invention provides a machine tool including a machining tool for machining a workpiece, a bed for supporting one of the workpieces, and a hybrid mechanism operable with respect to the bed. The hybrid mechanism rotates a link head supporting the other of the processing tool and the workpiece around the first axis and moves along a second axis orthogonal to the first axis. A parallel mechanism; a first drive mechanism for operating the parallel mechanism; and a serial mechanism that moves the parallel mechanism along a third axis that intersects the second axis in a plane orthogonal to the first axis. A second drive mechanism for operating the serial mechanism, and a link head provided in an absolute coordinate system. A command value corresponding to the moving position and the moving position is converted into a command value for the first drive mechanism and the second drive mechanism based on a mechanism parameter that defines a configuration of the entire mechanism including the parallel mechanism and the serial mechanism. And a control unit that drives and controls the first drive mechanism and the second drive mechanism, and the control unit sends command values corresponding to a rotation position and a movement position of the link head to the first drive mechanism and the second drive mechanism. A machine tool that calculates the drive amount of the first drive mechanism and the second drive mechanism based on a specific calculation formula from the rotation position and the movement position of the link head when converting into a command value for the second drive mechanism. provide.

  According to the present invention, it is possible to correct the machining parameters and the assembly errors of each component by correcting the mechanism parameters that define the overall configuration of the hybrid mechanism. Can be reduced.

[Embodiment]
FIG. 1 is a plan view for explaining the entire machine tool according to the embodiment of the present invention. FIG. 2 is a block diagram for explaining the machine tool control apparatus according to the embodiment of the present invention. FIG. 3 is a perspective view shown for explaining the main part of the machine tool according to the embodiment of the present invention. FIG. 4 is a plan view for explaining the main part of the machine tool according to the embodiment of the present invention. In the following description, the three directions orthogonal to each other are defined as the Z-axis direction (main axis direction in FIG. 1) and the X-axis direction (direction perpendicular to the Z-axis in FIG. 1) and the Y-axis direction (X Axis and the direction orthogonal to the Z axis).

[Overall configuration of machine tool]
1 and 2, a machine tool indicated by reference numeral 1 is composed of, for example, a cylindrical grinding machine, and is generally composed of a machine tool main body 2, a control device 3, and an accessory device (not shown).

(Configuration of machine tool body 2)
As shown in FIG. 1, the machine tool body 2 includes a work support drive unit 100 that supports a work W so as to be rotationally driven, a wheel rotation spindle unit 200 on which a processing tool 501 such as a grindstone is detachably mounted, and a parallel A hybrid mechanism 500 having a mechanism 300 and a serial mechanism 400 is provided.

<Configuration of Work Support Drive Unit 100>
As shown in FIG. 1, the work support drive unit 100 includes a headstock base 101 and two left and right headstocks 103, 103, and is mounted on a front end portion (lower side in FIG. 1) on a bed (base) 10. Is placed.

  On the rear surface (upper side in FIG. 1) of the headstock base 101, two headstock slide guides 102, 102 are arranged in parallel with each other at a predetermined interval in the left-right (Z-axis) direction and extending in the Z-axis direction. It is installed.

  The headstocks 103 and 103 are arranged on the corresponding headstock slide guides 102 and 102 so as to be movable along the Z-axis direction. Each of the headstock slide guides 102 and 102 is positioned at a predetermined position, and the workpiece W is sandwiched between the center portions thereof. Spindle drives 103 and 103 are equipped with spindle drive motors 104 and 104 that respectively drive the spindles 105 and 105 at a predetermined rotational speed.

<Configuration of wheel rotation spindle unit 200>
As shown in FIG. 1, the wheel rotation spindle unit 200 includes a wheel rotation spindle 201 capable of gripping a gripped portion of the processing tool 501, and a wheel rotation spindle drive motor (not shown) that rotationally drives the wheel rotation spindle 201. And is mounted on the link head 301. The rotation driving force of the wheel rotation main shaft drive motor is transmitted to the wheel rotation main shaft 201, and the processing tool 501 on the wheel rotation main shaft 201 is rotated at a predetermined rotation number.

<Configuration of hybrid mechanism 500>
As shown in FIGS. 3 and 4, the hybrid mechanism 500 includes the parallel mechanism 300 and the serial mechanism 400 described above, and is disposed on the bed 10 (shown in FIG. 1). The driving force is received from a first driving mechanism (head driving mechanism 302 and link driving mechanisms 304 and 305) for operating the parallel mechanism 300 and a second driving mechanism (rail driving mechanism) for operating the serial mechanism 400. And configured to operate in a plane orthogonal to the Y axis.

  3 and 4, the parallel mechanism 300 includes a head drive mechanism 302 for moving the link head 301 along the X-axis direction, and one end (head side end) parallel to the X-axis and the Z-axis. A link mechanism 303 including a pair of links 303A and 303B connected to each other so as to be rotatable about an axis parallel to the Y axis in a horizontal plane, and the other ends (rail side) of the links 303A and 303B of the link mechanism 303 And a pair of link drive mechanisms 304 and 305 for moving the end portions along the X-axis direction, respectively, and disposed on the bed 10 (shown in FIG. 1).

  The link head 301 includes a head rotary joint 3010 and a linear motion joint 3011. The head rotary joint 3010 is disposed on the slider guide rails 306 and 306 on the bed 10 so as to be movable via the slider 3012 and is linearly movable. A joint 3011 is rotatably supported by a head mounting side end (link free end) of the link mechanism 303 (links 303A and 303B) via a link connecting rotary joint 3030. Then, it moves along the X axis (second axis) direction via the slider 3012 on the rails 306, 306, and around the axis line (first axis: B axis) parallel to the Y axis at the head rotary joint 3010. It is comprised so that it can rotate.

  The link connecting rotary joint 3030 is configured to function as a one-degree-of-freedom joint that rotates about an axis parallel to the Y-axis.

  A joint guide that extends in a direction parallel to the rotation axis T (shown in FIG. 4) of the processing tool 501 and guides the linear motion joint 3011 in a uniaxial direction perpendicular to the Y axis is provided on the upper surface of the link head 301. A rail 3013 (shown in FIG. 3) is disposed.

  An angle sensor 380 (shown in FIG. 2) such as an encoder that detects the rotation amount (rotation angle) of the head rotary joint 3010 is disposed on the lower surface of the link head 301.

  The head rotation joint 3010 functions as a one-degree-of-freedom joint that rotates about the first axis, is disposed on the lower surface portion of the link head 301, and is linearly moved from the position where the link connection rotation joint 3030 is disposed. The joint 3011 is disposed so as not to move at a position offset in the moving direction.

  The linear motion joint 3011 is movably disposed on the rail 3013. As a result, the link connecting rotary joint 3030 is guided to move along the rail 3013 together with the linear motion joint 3011.

  The head drive mechanism 302 includes a feed screw 3020 that moves the slider 3012 and a servo motor 3021 that drives the feed screw 3020, and is connected to the control device 3 (interface 73) via a servo motor unit 80. The link head 301 is moved along the X-axis direction via the slider 3012 so that the position and posture of the link head 301 can be changed together with the link drive mechanisms 304 and 305 and the rail drive mechanism (not shown). Has been. A motor rotation detection encoder 3022 for detecting the rotation amount of the servo motor 3021 is attached to the head drive mechanism 302.

  The link mechanism 303 has a pair of links 303 </ b> A and 303 </ b> B that can swing in the same virtual plane as the movement / rotation plane of the link head 301, and is disposed behind the work support drive unit 100. And it is comprised so that the upper part of the link head 301 may be hold | maintained at the tool attachment part (link free end part) side.

  One link 303A is rotatably connected via a link rotary joint 3032A to a slider 3031A whose one link end moves on a slider guide rail 3030A above the bed 10, and the other link end is The link head 301 is rotatably connected via a link connecting rotary joint 3030.

  The rail 3030A is formed by a guide member extending along the X-axis direction, and is configured to guide a link end portion on one side of the one link 303A. Note that although the rail 3030A described in this embodiment is described as being parallel to the X axis (rails 306 and 306), the present invention is not limited to this, and the rail 3030A may be in a plane orthogonal to the Y axis. It may be inclined with respect to the X axis. The link rotation joint 3032A is configured to function as a one-degree-of-freedom joint that rotates about an axis parallel to the Y-axis.

  The other link 303B is rotatably connected via a link rotary joint 3032B to a slider 3031B whose one link end moves on a slider guide rail 3030B above the bed 10, and the other link end is The link head 301 is rotatably connected via a link connecting rotary joint 3030. The link length of the link 303B is set to the same dimension as the link length of the link 303A.

  The rail 3030B is formed of a guide member that is parallel to the rail 3030A at a predetermined interval in the Z-axis direction and extends along the X-axis direction. And it is comprised so that the link edge part of the one side in the other link 303B may be guided. Note that although the rail 3030B described in this embodiment is described as being parallel to the X axis (rails 306 and 306), the present invention is not limited thereto, and the rail 3030B may be in a plane orthogonal to the Y axis. It may be inclined with respect to the X axis. The link rotary joint 3032B is configured to function as a one-degree-of-freedom joint that rotates about an axis parallel to the Y-axis.

  One link driving mechanism 304 includes a feed screw 3040 for moving the slider 3031A and a servo motor 3041 for driving the feed screw 3040, and is connected to the control device 3 (interface 73) via the servo motor unit 80. . Then, the link end on one side of the link 303A is moved along the X-axis direction via the slider 3031A, and the link head 301 is rotated around an axis parallel to the Y-axis. A motor rotation detection encoder 3042 for detecting the rotation amount of the servo motor 3041 is attached to the link drive mechanism 304.

  The other link drive mechanism 305 includes a feed screw 3050 that moves the slider 3031B and a servo motor 3051 that drives the feed screw 3050, and is connected to the control device 3 (interface 73) via the servo motor unit 80. . Then, the link end on one side of the link 303B is moved along the X-axis direction via the slider 3031B, and the link head 301 is rotated around an axis parallel to the Y-axis. A motor rotation detection encoder 3052 that detects the rotation amount of the servo motor 3051 is attached to the link drive mechanism 305.

  On the other hand, as shown in FIGS. 3 and 4, the serial mechanism 400 includes slider guide rails 3030A and 3030B arranged in parallel in the Z-axis direction at a predetermined interval, and these rails 3030A and 3030B are connected to a first axis (Y-axis). And a rail drive mechanism (not shown) for moving along a third axis (in the present embodiment, an axis parallel to the Z axis) that intersects the second axis in a plane orthogonal to the Are disposed via slider guide rails 3032 and 3032. The parallel mechanism 300 is configured to move along the third axis.

  The rails 3030A and 3030B have a pair of sliders 3031 and 3031 arranged in parallel at a predetermined interval in the X-axis direction, and are movably disposed on the rails 3032 and 3032 on the bed 10 via the sliders 3031 and 3031. Yes. And it is comprised so that it can move along a Z-axis direction by a rail drive mechanism.

  The rail drive mechanism includes a feed screw (not shown) for moving the rails 3030A and 3030B, and a servo motor 6001 (shown in FIG. 2) for driving the feed screw. The control device 3 (interface 73) includes a servo motor unit. 80 is connected. Then, a moving force is applied to the rails 3030A and 3030B to move the parallel mechanism 300 along the Z-axis direction so that the position and posture of the link head 301 can be changed together with the head driving mechanism 302 and the link driving mechanisms 304 and 305. It is configured. A motor rotation detection encoder 6002 (shown in FIG. 2) for detecting the rotation amount of the servo motor 6001 is attached to the head drive mechanism.

(Configuration of control device 3)
As shown in FIG. 2, the control device 3 includes a CPU (central processing unit) 71, a memory 72, and interfaces (I / F) 73 to 75, and is a link head given by an orthogonal coordinate system (platform absolute coordinate system). The command values (X _PA , Z _PA , B _PA , d _PA ) corresponding to the movement position information 301 are _converted into mechanism parameters P (slide origin positions: SLO _XU1 , SLO _ZU1 , SLO _XU2 , SLO _ZU2 , SLO _XU3 , SLO _ZU3 , SLO _XU4 , SLO _ZU4 , slide angle: SLA _U1 , SLA _U2 , SLA _U3 , SLA _U4 ) converted into command values (output values) of the head drive mechanism 302 and link drive mechanisms 304, 305 and rail drive mechanism Actuator coordinates (U ₁ , U ₂ , U ₃ , U ₄ ) are obtained and these head drives are obtained. The moving mechanism 302 and the link driving mechanisms 304 and 305 are configured to drive and control the rail driving mechanism.

The mechanism parameter P defines the configuration of the entire mechanism (hybrid mechanism 500) including the parallel mechanism 300 and the serial mechanism 400. In addition to the link length, the movement of the head rotary joint 3010 (slider 3012) relative to the X axis of the platform absolute coordinate system. Including the tilt of the direction (slide angle SLA _U3 ), the tilt of the movement direction of the parallel mechanism 300 with respect to the Z axis of the platform absolute coordinate system (slide angle SLA _U4 ), and the like.

  In the control device 3 (customer board), the following coordinate conversion is performed when converting the output values of the head drive mechanism 302 and the link drive mechanisms 304 and 305 and the rail drive mechanism. FIG. 5 is a plan view for explaining a case where the reference coordinate system of the machine tool according to the embodiment of the present invention is converted into a machine coordinate system. FIG. 6 is a plan view for obtaining actuator coordinates of the machine tool according to the embodiment of the present invention. FIG. 7 is a diagram for obtaining the drive amount of the actuator and the position coordinates of the machining tool in the machine tool according to the embodiment of the present invention.

First, as shown in FIG. 5, the tool support-side end face of the head stock 103 and 103 (the spindle 105, 105) the reference coordinate system, including the holding and the workpiece W by (workpiece coordinate system) _{O W} parallel to the link head 301 the machine coordinate system O _M containing converts support-side end face of the link head 301 and the relative coordinate system including a head rotary joint 3010 that (platform coordinate system) to O _P. In FIG. 5, the origin of the platform coordinate system is (Z _M -PO _Z , X _M -PO _X , B _M -PO _B ). The offset amounts of the platform coordinate system origin are ZOfs, XOfs, and BOfs. Therefore, the coordinates (Z _P , X _P , B _P ) of the end surface on the tool support side of the link head 301 in the platform coordinate system are obtained by the following formula.

Then converted platform coordinate system _{O P} platform absolute coordinate system _{O PA} including a head rotary joint 3010 and the serial mechanism 400 of the link head 301. In FIG. 5, the offset amounts from the tool support side end face of the head rotary joint 3010 of the link head 301 in the platform absolute coordinate system are TPJOz and TPJOx. For this reason, the coordinates (Z _PA , X _PA , B _PA ) of the head rotary joint 3010 of the link head 301 in the platform absolute coordinate system are obtained by the following equations.

Then, from the rotation position and movement position of the link head 301 in the platform absolute coordinate system O _PA (position coordinates of the head rotary joint 3010: Z _PA , X _PA , B _PA , d _PA ), the following calculation formula (inverse conversion formula) Based on the above, the driving amounts of the head driving mechanism 302 and the link driving mechanisms 304 and 305 and the rail driving mechanism 600 are calculated. Thereby, the actuator coordinates (U ₁ , U ₂ , U ₃ , U ₄ ) can be obtained.

In this case, in the platform absolute coordinate system shown in FIG. 6, assuming that the position coordinates of the head rotary joint 3010 and the inclination of the rotation axis T of the processing tool 501 are (X _PA , Z _PA ) and B _PA , respectively, the rail side of the link 303A The position coordinates (X ₁ , Z ₁ ) of the end and the position coordinates (X ₀ , Z ₀ ) of the link connecting rotary joint 3030 can be expressed as follows.

  The above formula can be rearranged and expressed as the following formula.

Thus, the amount of movement of the rail-side end of the link 303A (drive amount of the link drive mechanism 304) is determined as U ₁ is shown below.

Similarly, the amount of movement of the rail-side end of the link 303B (the driving amount of the link drive mechanism 305) is determined as U ₂ is shown below.

Further, the platform absolute coordinate system shown in FIG. 6, when the respective _{SLA U3} moving direction of inclination of the slider 3012, the movement amount of the head rotary joint 3010 (driving of the head driving mechanism 302) _{U 3} as is shown below Desired.

Similarly, when the inclination of the direction of movement of the parallel mechanism 300 for _{Z PA-axis} platform absolute coordinate system and _{SLA U4,} rails 3030A, the movement amount of 3030B (drive amount of the rail drive mechanisms 600) _{U 4} so that the following Is required.

Thereafter, the actuator coordinates (U _1G , U _2G , U _3G , U _4G ) are calculated based on the following calculation formula and then displayed on the screen of the image display device (CRT) 77.

Thus, in this embodiment, converts the mechanical coordinate system O _M parallel to the work coordinate system O _W platform coordinate system O _P, then the platform coordinate system O _P platform absolute coordinate system O _PA after the conversion, the head driving mechanism 302 based on the rotation position and the movement position of the link head 301 in the platform absolute coordinate system O _PA specific calculation formula from (position coordinates of the head rotary joint 3010) (inverse transformation equation), links Although the case where the drive amounts of the drive mechanisms 304 and 305 and the rail drive mechanism are calculated has been described, a series of these flows is as shown in FIG.

7, the head driving mechanism 302, the amount of driving of the link drive mechanism 304, 305 and the rail drive mechanisms determining the position coordinates of the tool support-side end face of the link head 301 in the machine coordinate system O _M, the case opposite It is carried out according to the flow. That is, the head driving mechanism 302, the rotational position and the movement position of the link head 301 in platform absolute coordinate system O _PA based on a specific calculation formula from the driving amount of the link drive mechanism 304, 305 and rail drive mechanisms (forward conversion formula) calculated (the position coordinates of the head rotary joint 3010), then converts the platform absolute coordinate system O _PA platform coordinate system O _P including the rotational position and the moving position of the link head 301, the platform coordinate system O converts the platform coordinate system O _P to the machine coordinate system O _M comprising tool support-side end face of the link head 301 in _P obtains the position coordinates of the tool support-side end face of the link head 301 in the machine coordinate system O _M.

<Configuration of CPU 71>
The CPU 71 reads and analyzes the machining program stored in the memory 72 or the external storage device 78, and based on the mechanism parameter P, the head drive mechanism 302 and the link drive based on the movement position / posture information of the link head 301 given in the platform absolute coordinate system. The mechanism 304, 305 is converted into a drive command value for the rail drive mechanism and output to the servo motor unit 80.

<Configuration of memory 72>
The memory 72 stores various information such as a machining program for executing an actual machining process by the machining tool 501 and a mechanism parameter P.

<Configuration of interfaces 73 to 75>
The interface 73 includes a servo motor unit 80 (81 to 84) that drives the head drive mechanism 302 (servo motor 3021), the link drive mechanisms 304 and 305 (servo motors 3041 and 3051), and the rail drive mechanism (servo motor 6001). It is connected. The servo motor units 81 to 84 drive the head drive mechanism 302, the link drive mechanisms 304 and 305, and the rail drive mechanism based on the command value from the CPU 71, respectively, and the motor rotation detection encoder 3022 and the link of the head drive mechanism 302. Feedback control is executed by the output from the motor rotation detection encoders 3042 and 3052 of the drive mechanisms 304 and 305 and the motor rotation detection encoder 6002 of the rail drive mechanism. Connected to the interface 74 are a keyboard (KB) 76 for inputting machining data and the like, an image display device (CRT) 77 for displaying machining data, the state of the machine tool 1 and the like, and an external storage device 78 for storing machining data. Has been. An angle sensor 380 is connected to the interface 75.

(Attachment configuration)
The accessory device includes an oil supply device, a cooling device, an air supply device, a coolant supply device, and a duct device that connects these devices to the machine tool body 2.

[Operation of machine tool 1]
Next, the operation of the machine tool according to the present embodiment will be described with reference to FIGS. FIG. 8 is a plan view for explaining the XZ-axis parallel operation of the link head in the machine tool according to the embodiment of the present invention. FIG. 9 is a plan view for explaining the rotation operation of the link head in the machine tool according to the embodiment of the present invention. FIG. 10 is a plan view for explaining the advantages when the machine tool according to the embodiment of the present invention is provided with a head drive mechanism. FIG. 11 is a plan view for explaining the XZ axis parallel / rotating operation of the link head in the machine tool according to the embodiment of the present invention. In addition, in FIGS. 8-11, the linear motion joint etc. are abbreviate | omitted.

"X-Z axis parallel motion"
Head rotary joint 3010 (sliders 3012) along the rails 306, 306, also link pivot joints 3032A, 3032B (slider 3031,3031) respectively rails 3030A, in the same direction with the same moving amount _{X 1} along 3030B causes moved, the rail 3030A, is moved by the moving amount _{Z 1} a along the rail 3032,3032 3030B, link head 301 in a state where the rotation axis T and is matched to the reference line O of the processing tool 501 in FIG. 82 It moves in the X-axis and Z-axis directions from the initial position indicated by the dotted line and is arranged at the position indicated by the solid line in FIG.

"Rotating motion"
When the link rotary joints 3032A and 3032B (sliders 3031A and 3031B) are moved in the same direction along the rails 3030A and 3030B with different movement amounts X ₁ and X ₂ (X ₁ > X ₂ ), the link head 301 is moved as shown in FIG. FIG. 9 shows a solid line in FIG. 9 in a state in which, for example, the rotation axis T of the processing tool 501 intersects the reference line O by rotating counterclockwise around an axis parallel to the Y axis from the initial position indicated by a two-dot chain line. Placed in position.

Here, as shown in FIG. 10, when the link head 301 is arranged with the rotation axis T of the machining tool 501 orthogonal to the reference line O during workpiece machining, the head rotation joint 3010 (slider 3012) is moved to the rail 306. , 306 can be moved to the workpiece side (downward in FIG. 10), that is, a reaction force F can be generated in the link head 301 against the acting forces f ₁ and f _{2 in the} X-axis direction. For this reason, the singular point which cannot generate reaction force F in the link head 301 with respect to the acting forces f ₁ and f ₂ in the X-axis direction can be eliminated.

"X-Z parallel / rotating motion"
The link rotary joints 3032A and 3032B (sliders 3031A and 3031B) are moved in the same direction along the rails 3030A and 3030B with different movement amounts X ₁ and X ₂ (X ₁ > X ₂ ), and then the rails 3030A and 3030B are moved. is moved by the moving amount _{Z 1} along the rails 3032,3032, head rotary joint 3010 (sliders 3012) along the rails 306, 306, also link pivot joints 3032A, 3032B (sliders 3031A, 3031B) the rails 3030A, moving each in the same direction with the same moving amount X ₃ along 3030B, rotated from the initial position shown link head 301 by the two-dot chain line in FIG. 11 in a counterclockwise direction about an axis parallel to the Y axis The rotation axis T of the processing tool 501 is the reference line 11 is arranged at a position indicated by a one-dot chain line in FIG. 11 while crossing O, and further moved in the X-axis direction to be arranged at a position indicated by a solid line in FIG.

  As described above, in this embodiment, the link head 301 is moved by moving at least one of the X axis and the Z axis along one of the axes and rotating around the axis parallel to the Y axis. The position and orientation of the head 301 are controlled, and the position of the workpiece W is controlled by moving the headstocks 103 and 103 along the Z-axis direction, and the work W sandwiched between the headstocks 103 and 103 is processed. be able to.

In this case, the slider in the platform absolute coordinate system _{O PA} 3012,3031A, 3031B, when positioning the 3031,3031, the position of the rotary link connection on the link head 301 joint 3030 and the head rotating joint 3010 is determined, the link head The movement / rotation position 301 (the tip position of the processing tool 501) is determined. Therefore, in order to position the link head 301 at a desired movement / rotation position, the sliders 3012, 3031 A, 3031 B, 3031, and 3031 are determined from these movement / rotation positions based on a specific arithmetic expression (inverse conversion expression). The position is calculated, and the sliders 3012, 3031A, 3031B, 3031 and 3031 are moved to positions corresponding to these calculated values.

  In the present embodiment, the parallel mechanism 300 includes a head drive mechanism 302, a link drive mechanism 304, and a link drive mechanism 305 that drive the link head 301, the link 303A, and the link 303B, respectively. In this case, the head drive mechanism 302 exists as a redundant drive mechanism, but the linear joint 3011 is not directly displaced by the presence of the redundant head drive mechanism 302 and the other link drive mechanisms 304 and 305. However, in reality, the mechanism parameter P is not theoretical and includes errors due to the use environment such as manufacturing error, assembly error, temperature change, etc. of each component constituting the parallel mechanism 300 and long-term use. The joint 3011 is displaced to absorb these errors.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

(1) It is possible to correct a machining error and an assembly error of each component by correcting a mechanism parameter that defines the configuration of the entire hybrid mechanism. This eliminates the need to correct the mechanism parameters for each mechanism when correcting the machining error and assembly error of each component, thus reducing the machining accuracy and assembly accuracy of each component and reducing the cost. Can be achieved.

(2) Eliminating the need to individually correct the mechanism parameters of each mechanism can alleviate the burden on the operator.

(3) Since the link head 301 can be moved by the head driving mechanism 302, the existing singularity can be eliminated, and the movable range of the link head 301 can be expanded.

(4) Since the link connecting rotary joint 3030 can move on the link head 301 via the linear motion joint 3011, the processing accuracy of each component and the assembly accuracy between components are poor, or the link 303A. , 303B can absorb various errors caused by errors in the mechanism parameters such as when it expands and contracts due to thermal changes during use, etc., and the components and head drive mechanisms 302, link drive mechanisms 304, 305 caused by these errors can be absorbed. Overloading can be prevented.

  As mentioned above, although the machine tool of this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment, It implements in a various aspect in the range which does not deviate from the summary. For example, the following modifications are possible.

(1) In this embodiment, the case where the machining tool 501 as a control target includes the parallel mechanism 300 held by the link head 301 has been described. However, the present invention is not limited to this, and a workpiece is placed on the link head. It may be provided with a parallel mechanism for holding.

(2) In the present embodiment, the case where the grindstone is applied to the machine tool 1 using the processing tool 501 has been described. However, the present invention is not limited to this, and for example, a turning tool such as an electrodeposition wheel for turning or a surface finish. Of course, the present invention can be applied to other machine tools using a tool or the like as a processing tool.

The top view shown in order to demonstrate the whole machine tool which concerns on embodiment of this invention. The block diagram shown in order to demonstrate the control apparatus of the machine tool which concerns on embodiment of this invention. The perspective view shown in order to demonstrate the principal part of the machine tool which concerns on embodiment of this invention. The top view shown in order to demonstrate the principal part of the machine tool which concerns on embodiment of this invention. The top view shown in order to demonstrate the case where the reference | standard coordinate system of the machine tool which concerns on embodiment of this invention is converted into a machine coordinate system. The top view shown in order to obtain | require the actuator coordinate of the machine tool which concerns on embodiment of this invention. The figure shown in order to obtain | require the drive amount of the actuator in the machine tool which concerns on embodiment of this invention, and the position coordinate of a processing tool. The top view shown in order to demonstrate the XZ axial parallel operation | movement of the link head in the machine tool which concerns on embodiment of this invention. The top view shown in order to demonstrate rotation operation | movement of the link head in the machine tool which concerns on embodiment of this invention. The top view shown in order to demonstrate the advantage at the time of providing the machine tool which concerns on embodiment of this invention with the head drive mechanism. The top view shown in order to demonstrate XZ axis parallel and rotation operation | movement of the link head in the machine tool which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Machine tool 2 ... Machine tool main body 3 ... Control apparatus 10 ... Bed 71 ... CPU
72 ... Memory 73-75 ... Interface 76 ... Keyboard 77 ... Image display device 78 ... External storage device 80-83 ... Servo motor unit 100 ... Work support drive unit, 101 ... Spindle base, 102 ... Spindle base slide guide, 103 ... Spindle base 104 ... Spindle drive motor 105 ... Spindle 300 ... Parallel mechanism 301 ... Link head, 3010 ... Head rotary joint, 3011 ... Linear motion joint, 3012 ... Slider, 3013 ... Rail for joint guide, 3014 ... Connection part 302 ... head drive mechanism, 3020 ... feed screw, 3021 ... servo motor, 3022 ... encoder for motor rotation detection 303 ... link mechanism, 3030 ... rotation joint for link connection 303A ... link, 3030A ... slider guide rail, 303 A ... Slider, 3032A ... Link rotation joint, 3033A ... Link branch, 3034A ... Base 303B ... Link, 3030B ... Slider guide rail, 3031B ... Slider, 3032B ... Link rotation joint, 3033B ... Link branch, 3034B ... Base 304 ... Link drive mechanism, 3040 ... Feed screw, 3041 ... Servo motor, 3042 ... Encoder for motor rotation detection 305 ... Link drive mechanism, 3050 ... Feed screw, 3051 ... Servo motor, 3052 ... Encoder for motor rotation detection 306 ... Rail for guiding the slider 380 ... Angle sensor 400 ... Serial mechanism 500 ... Hybrid mechanism 6001 ... Servo motor 6002 ... Encoder for motor rotation detection 501 ... Processing tool 3031 ... Slider 3 32 ... rail O ... reference line T ... rotation axis W of the slider guide ... work

Claims (5)

A machining tool for machining a workpiece, and a parallel mechanism for rotating a link head supporting one of the workpieces around a first axis and moving along a second axis perpendicular to the first axis;
A first drive mechanism for operating the parallel mechanism;
A serial mechanism that moves the parallel mechanism along a third axis that intersects the second axis in a plane perpendicular to the first axis;
A second drive mechanism for operating the serial mechanism;
The command values corresponding to the rotation position and the movement position of the link head given in an absolute coordinate system are based on a mechanism parameter that defines a configuration of the entire mechanism including the parallel mechanism and the serial mechanism, and the first drive mechanism and A controller that converts the command value to the second drive mechanism and controls the drive of the first drive mechanism and the second drive mechanism;
The control unit converts the command value corresponding to the rotation position and the movement position of the link head into the command value for the first drive mechanism and the second drive mechanism. A hybrid mechanism that calculates drive amounts of the first drive mechanism and the second drive mechanism based on a specific calculation formula. The controller is
A machine coordinate system including a support side end surface of the link head parallel to a reference coordinate system including a base supporting the other of the processing tool and the workpiece, and including a support side end surface of the link head and a head rotating portion thereof. Convert to relative coordinate system,
Next, after converting the relative coordinate system to the absolute coordinate system including the head rotation unit of the link head and the serial mechanism,
2. The hybrid mechanism according to claim 1, wherein drive amounts of the first drive mechanism and the second drive mechanism are calculated from a rotation position and a movement position of the link head in the absolute coordinate system.   The control unit determines the inclination of the movement direction of the link head with respect to one of two axes orthogonal to each other in the absolute coordinate system, and the inclination of the movement direction of the parallel mechanism with respect to the other of the two axes. The hybrid mechanism according to claim 1, wherein the command value is converted by being included in a mechanism parameter.   The parallel mechanism has one end connected to the link head so as to be rotatable in a plane perpendicular to the first axis, the other end being rotatable about an axis parallel to the first axis, and the second A link mechanism comprising a pair of links supported so as to be movable along an axis, wherein one end of the pair of links is disposed on the link head so as to be relatively movable in one axial direction perpendicular to the first axis. The hybrid mechanism according to claim 1. A processing tool for processing a workpiece, and a bed for supporting one of the workpieces;
A machine tool equipped with a hybrid mechanism operable with respect to the bed,
The hybrid mechanism is
A parallel mechanism for rotating the link head supporting the other of the processing tool and the workpiece around a first axis and moving the link head along a second axis perpendicular to the first axis;
A first drive mechanism for operating the parallel mechanism;
A serial mechanism that moves the parallel mechanism along a third axis that intersects the second axis in a plane perpendicular to the first axis;
A second drive mechanism for operating the serial mechanism;
The command values corresponding to the rotation position and the movement position of the link head given in an absolute coordinate system are based on a mechanism parameter that defines a configuration of the entire mechanism including the parallel mechanism and the serial mechanism, and the first drive mechanism and A controller that converts the command value to the second drive mechanism and controls the drive of the first drive mechanism and the second drive mechanism;
The control unit converts the command value corresponding to the rotation position and the movement position of the link head into the command value for the first drive mechanism and the second drive mechanism. A machine tool that calculates drive amounts of the first drive mechanism and the second drive mechanism based on a specific calculation formula.

Images