JPH0685136B2 - Complex eccentric precision positioning controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a combination of an eccentric rotor and an X-type rotary mechanism.
The present invention relates to a complex eccentric type precision positioning control device capable of 3-Y-θ positioning.

(Prior Art) Conventionally, as a device for moving and positioning a work table or the like in a two-dimensional plane, a cylinder device such as a hydraulic drive for the X and Y axes, a rack and pinion mechanism driven by a pulse motor or a servo motor, a ball screw, etc. A linear feed mechanism such as a mechanism and a belt mechanism is arranged to form a biaxial mechanism section, and linear control is separately performed in time series for each of the X-axis and the Y-axis to drive and move them to an arbitrary position. The positioning control on the XY plane differs depending on the combination of a feed mechanism such as a ball screw provided on one axis, an AC or DC servo motor, or a pulse motor, etc. Input the coefficient to the control circuit in advance,
The control of the method of increasing the positioning accuracy is performed.

(Problems to be Solved by the Invention) Since a conventional two-dimensional in-plane positioning device performs linear control separately along the XY axes, it is necessary to perform a non-linear movement in steps. In order to draw a line-shaped locus and minimize it, the biaxial mechanism and the control device are complicated and expensive. In addition, the positioning device of the conventional orthogonal coordinate system has a mechanical limit in positioning accuracy and also has a limit in speeding up because of a rapid change in acceleration. The present inventor has previously proposed an eccentric type electric direct drive positioning device composed of a combination of eccentric rotors that are electrically driven directly, as a positioning device that solves the drawbacks of the above-described conventional linear driving positioning device for two axes.

The present invention was devised to provide a dedicated control device for the above complex eccentric precision positioning device, and it is an XY-θ 3 system that combines an eccentric rotor with a rotating mechanism.
It is an object of the present invention to provide a control device that can perform axis positioning with high efficiency, high speed, and high accuracy, and can perform complicated linear / non-linear positioning control in the XY plane of the output shaft.

(Means for Solving Problems) A compound eccentric precision positioning control device according to the present invention has the above-described object. A fixed base cylinder, and a plurality of two-dimensional surface translational eccentricities that are sequentially eccentric to the fixed base cylinder. A rotor, and an output shaft rotor for fixing an object to be positioned, which is provided at an eccentric position of an eccentric rotor at a final stage of the eccentric rotor for two-dimensional surface translation, and each rotor is independently driven by an electric direct drive motor. A complex eccentric precision positioning control device capable of directly rotating to position an output shaft rotor in a two-dimensional position and a rotation angle, wherein a moving position in the two-dimensional surface is input in an XY coordinate system, Input means for inputting the rotation angle of the output shaft rotor by angle, calculation means for calculating each rotation angle of the eccentric rotor for two-dimensional surface translation and rotation angle of the output shaft rotor by input information from the input means, each electric direct drive Motor times Rotation angle detecting means for detecting a turning angle, comparing means for comparing the detected value of the rotating angle detecting means with the calculated value of the calculating means, and a motor drive for receiving each signal from the comparing means and driving each electric direct drive motor This is achieved by adopting a configuration characterized by being composed of a circuit.

(Operation) The eccentric amount of each eccentric rotor is combined by the rotation of each eccentric rotor. For example, the center of the second eccentric rotor B is eccentric from the center of the first eccentric rotor A by r ₁ and the center of the output shaft rotor C is Is eccentric by r ₂ from the center of the second eccentric rotor B, and if r ₁ ≦ r ₂ , the axis of the output shaft rotor C has a radius r ₁ + r ₂ about the center of the fixed base cylinder. It is possible to move within the range of the circle, and the object to be positioned can be moved to a desired position within the two-dimensional plane within the range. r ₁ ＞ r ₂
In the case of, it is possible to move within the range excluding the circle of the center radius r ₁ −r ₂ of the circle S of radius r ₁ + r ₂ .

In the above positioning device, the positioning control law of the present invention is applied to an example in which the translational movement in the XY plane is performed by two two-dimensional surface translational eccentric rotors having the same eccentricity (r ₁ = r ₂ = r). Will be explained.

The two-dimensional in-plane position of the positioning input is performed in the XY coordinate system, and the rotation angle of the output shaft is input as θ. The target rotation angle of the electric direct drive motor of each stage is calculated from the coordinate input, and the motor of each stage is controlled by the calculated value. Now, drive the direct drive motors Ma and Mb that drive the first-stage rotor A and the second-stage rotor B that are eccentric rotors for two-dimensional surface translation, and drive the third-stage rotor C that is the output shaft rotor. Direct drive motor Mc
When the relationship of each parameter with respect to the movement of is set as shown in FIG. 4, the following relationship is obtained. In the figure, the center point of the fixed base cylinder is used as the coordinate origin, and the center of the rotor B of the second stage can move on the circle b of radius r ₁ and the center moves on the circumference of the circle b. The center of the output shaft rotor C can move on a circle c having a radius r ₂ . Therefore, the center of the output shaft C can be moved to an arbitrary position within the circle s having the radius r ₁ + r ₂ .

If the apparent rotation angles of the electric direct drive motors with respect to the reference coordinate axes (X, Y) are θ ₁ , θ ₂ , θ ₃ and the actually rotated angles are α, β, γ, α = θ ₁ , β = θ _2- ? ₁ ,? =? _3- ? ₂ .

Now, in the case of r ₁ = r ₂ = r, the center of the output shaft rotor C is moved to an arbitrary point Q (x, y) located within a circle having a radius 2r with the origin O as the center, and the output shaft is moved. When rotating by the angle θ, the rotation angles of the direct drive motors Ma to Mc can be obtained as follows. From FIG. 4, since x = rcos θ ₁ + rcos θ ₂ r = rsin θ ₁ + rsin θ ₂ , x ² + y ² = 2r ² + 2r ² cos (θ ₁ −θ ₂ ) ∴ | θ ₁ −θ ₂ | = cos ⁻¹ {( x ² + y ² −2r ² ) / 2r ² } = | β | (1) On the other hand, since tan (θ ₁ + α ₁ ) = y / x, θ ₁ + α ₁ = tan ⁻¹ ( y / x) Also, since α ₁ = β / 2, θ ₁ = tan ⁻¹ (y / x) − (1/2) cos ⁻¹ {(x ² + y ² −2r ² ) / 2r} = α (2) Therefore, the rotational angles from the origin of the first-stage rotor A and the second-stage rotor B for moving the output shaft rotor to the Q point (x, y) position can be obtained from the equations (1) and (2). Since there are multiple solutions of equations (1) and (2), y> 0, x> 0 ⇒ first quadrant y> 0, x <0 ⇒ second quadrant y <0, x <in the program. The solution can be determined by providing a discriminant that determines 0⇒third quadrant y <0, x> 0⇒fourth quadrant x = 0, y = 0⇒origin.

On the other hand, the rotation angle of the output shaft rotor C is the rotor A and the rotor B.
Is rotated by α and β, which causes apparent rotation (α + β). Therefore, in order for the output rotor C to rotate θ _3, rotation must be corrected accordingly, and the rotation angle γ of the output shaft rotor is γ. = Θ ₃ − (α + β) (3)

Since α, β, and γ obtained as described above are all absolute angles from the reference point, if the output shaft rotor at the start of rotation is not at the reference point, it must be subtracted and corrected. I won't.

As described above, the control program of the arithmetic function for obtaining the rotation angle of each motor is made into a ROM and is incorporated in the main controller.
If the positioning position x, y, θ is given, the rotation angle of each rotor is calculated.

In the complex eccentricity type precision positioning device to which the present control device is applied, since each rotor serves as a rotor of the motor and is directly driven, the rotation angle of each motor directly becomes the rotation angle of each rotor. Therefore, if the outputs corresponding to α, β, γ of the encoder that is the rotation angle detection means of each motor are Ea, Eb, Ec, then Ea = α, Eb = β, Ec = γ = θ− (Ea + Eb) . Therefore, if α, β, γ are given as target values from the main controller to the servo system controller of each motor, feedback control is performed until the output values of the encoder become α, β, γ, respectively, and each motor is driven. By using a motor and encoder with high resolution, it is possible to perform ultra-precision positioning by compound rotation of those motors.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 3 shows an embodiment of a compound eccentric type precision positioning device to which the present invention is applied. The complex eccentric precision positioning device 1 has a fixed base cylinder 3 fixed to a machine base 2 and a cylindrical outer wall 4 fitted into the fixed base cylinder 3, and a cylindrical inner wall 5 is provided at a position eccentric from the axis. The formed first-stage eccentric rotor A has a cylindrical outer wall 6 that fits into the cylindrical inner wall 5 of the first-stage eccentric rotor A, and the cylindrical inner wall 7 is eccentric to the axial center of the cylindrical inner wall 7.
A second stage eccentric rotor B, and a hollow output shaft rotor C having a cylindrical outer wall 8 that fits into a cylindrical inner wall 7 of the second stage eccentric rotor B. These bearings 10 are ball bearings or the like. They are sequentially fitted through and rotatably assembled. Then, the first-stage eccentric rotor A is attached to the fixed base cylinder 3 and the second-stage eccentric rotor A is attached to each fitting portion.
Electric direct drive motors Ma to Mc that rotate the output eccentric rotor B independently of the output eccentric rotor B with respect to the second eccentric rotor B are provided. In this embodiment, a DC brushless motor is adopted as the electric direct drive motor,
Reference numeral 11 is a permanent magnet that is a field magnet of a rotor that constitutes the motor, and 12 is an amateur coil.
The first-stage eccentric rotor A and the second-stage eccentric rotor B have their eccentricities translated in a two-dimensional plane according to the amount of eccentricity at their respective rotation angles to form a two-dimensional plane translation rotor.

Therefore, when the object to be positioned is attached to the output shaft eccentric rotor C, the object to be positioned is eccentric by rotating the first-stage eccentric rotor A and the second-stage eccentric rotor B by their respective direct drive motors. By moving in a two-dimensional plane according to the amount and rotating the output shaft rotor C, the output shaft rotor C is rotated about its axis, and translational movement in a biaxial plane and positioning with three degrees of freedom of rotation can be performed. Since each rotor is directly driven by electric motor, it has extremely high resolution, can control fine movement of 0.10 micron order, and can perform highly accurate positioning.

1 and 2 are block diagrams of the control device of the positioning device configured as described above.

The control device of the present invention comprises a main controller 15, controllers 25a, 25b and 25c for each motor M of each stage, and motors Ma, Mb and Mc of each stage.

The main controller 15 is composed of a microcomputer or a personal computer, and basically, x, y, θ information as position designation information input from an input means such as a keyboard 16 or tape, and rotation angle detection of each motor given from an encoder Value θ
a, θb, θc (showing the current value of each rotor), an input interface 17, a central processing unit CPU 18, x,
It is composed of a ROM 19 in which a control program for calculating and controlling y and θ information for each drive angle of each rotor is stored, a RAM 20 for temporarily storing data, and an output interface 21.

The controller 25 of each motor includes a comparator 26 for comparing the difference between the target angles α, β, γ given by the main controller and the detected angle θr of each motor given by the encoder, and a deviation signal θε from the comparator 26. Compensation circuit 27 that processes the signal to stabilize the servo system and improve the positioning performance.
It is composed of a drive circuit 28 for controlling the energization timing to the amateur coil of the motor, a power amplifier 29, an encoder 30 for detecting the position of each rotor, and a displacement / angle conversion circuit 31 for converting the detection signal into an absolute angle by the encoder. There is.
The displacement / angle conversion circuit is necessary when an incremental encoder is used as the encoder 30, and is composed of a counter circuit that converts incremental information into an absolute value. Can be realized. The counter part is composed of C-MOS IC,
With battery backup, the current position of the motor can be stored even in the event of a power failure. Further, if the counter is provided in two lines, the origin can be reset and the original angle can be restored arbitrarily. The output from the displacement / angle conversion circuit is given to the comparator as feedback data, and is also input from the input interface as current position information.
A / D converted and given to the main controller.

Positioning control performed by the control device configured as described above will be described with reference to the flowchart shown in FIG.

When the positioning information xyθ is input from the keyboard (step), the current absolute rotation angles θa, θb, θ of each rotor
c is read (step). The rotation angle α of the first-stage rotor A and the rotation angle β of the second-stage rotor B, which are drive angles from the origin of each stage motor, are calculated, and thereby the corrected rotation angle γ of the output shaft rotor C is calculated. Further, the drive rotation angle of each rotor is corrected by the current absolute rotation angles θa, θb, and θc of each rotor (step). Output the set angle to each stage controller and start driving each motor (step),
Each motor is driven until the current angle of each motor matches the set angle (step). When they match, the movement completion signal is output to the main controller and the process ends (step).

If necessary, the main controller calculates the current output axis position from the detected rotation angle of each motor input through the displacement / angle changer and outputs it to the CRT to display the current output axis position on the screen. To do. Further, the rotation of each rotor from the current position to the target position can be made faster by programming the rotor so that it rotates closer to the stroke.

In the above embodiments, the brushless DC is used as the direct drive motor.
Although a motor is used, a pulse motor or the like can be adopted without being limited to the motor.

(Effect) As described above, since the control device of the present invention has the positioning calculation means for converting XY-θ into a rotation angle, even if the output is a rotational motion, the XY coordinate is used. It can be input, the position can be easily specified, and the control is simple. Further, since the controller for controlling the three-axis mechanism unit (motor) and the main controller unit for calculating the target angle and giving a command to the controller are separately provided, it is possible to drive the motors at the same time and control them efficiently and at high speed. .

Further, since the two-dimensional surface is moved only by the combination of the rotations of the eccentric rotor, it is possible to make the cycloid curve relatively freely and perform a non-linear complicated movement. In addition, since the encoder directly detects the rotation angle of each rotor and performs positioning, it is possible to perform ultra-precision positioning without backlash unlike the conventional linear driving positioning.

Further, since the control program for converting the position designation information x, y, θ into the drive angle of each rotor is ROMized, the control is easy, and even if the eccentricity is different, the control program is not changed, Enlarged / reduced movement can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device of the present invention, FIG. 2 is a block diagram of a main control portion, and FIG. 3 is a front sectional view of an embodiment of a compound eccentric precision positioning device to which the present invention is applied. , FIG. 4 is a chart showing the relationship between the position designation input values x, y, θ and the rotation angle αβγ of each rotor, and FIG. 5 is a flowchart of the control device of the present invention. A: 1st eccentric rotor, B: 2nd eccentric rotor C: Output shaft rotor, M: Electric direct drive motor 1: Complex eccentric precision positioning device 3: Fixed base cylinder, 15: Main controller 16: Input interface, 18: CPU 19: ROM, 21: Output interface 25: Controller, 26: Comparator 27: Compensation circuit, 28: Drive circuit, 29: Power amplifier, 30: Encoder, 31: Displacement / angle conversion circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seizo Suzuki 3-8-4 Shinkawa, Mitaka City, Tokyo (72) Inventor Naoaki Kuwano 7-43-3 Jindaiji Higashi-cho, Chofu City, Tokyo (72) Inventor Yoshinori Sakai 1 Kawasaki-cho, Kakamigahara-shi, Gifu Kawasaki Heavy Industries, Ltd. Gifu factory (72) Inventor Kenji Ogimoto 1 Kawasaki-cho, Kakamigahara-shi, Gifu Kawasaki Heavy Industries, Ltd. Gifu factory (72) Inventor Yasuaki Taniguchi Kagamihara, Gifu prefecture Ichikawasaki, Ichi, Kawasaki Heavy Industries, Ltd., Gifu Factory (72) Inventor, Hiroshi Kawaguchi 1, Kawasaki-machi, Kakamigahara-shi, Gifu Prefecture, Kawasaki Heavy Industries, Ltd., Gifu, Ltd. (72) Inventor, Genma Hara, 20 Ishigane, Toyama, Toyama Prefecture Fujikoshi Co., Ltd. (72) Inventor Makoto Hamada 20 Ishigane, Toyama City, Toyama Prefecture Fujikoshi Co., Ltd. (72) Inventor Goji Inaba Toyama Prefecture 20 Ishigane, Toyama City Fujikoshi Co., Ltd. (56) Reference JP-A-63-92242 (JP, A) JP-A-59-60615 (JP, A) JP-A-54-82779 (JP, A)

Claims (1)

[Claims] 1. A fixed base cylinder, a plurality of two-dimensional surface translational eccentric rotors which are sequentially eccentric to the fixed base cylinder and are provided in multiple stages, and at the eccentric position of the final stage of the two-dimensional surface translational eccentric rotor. An output shaft rotor for fixing an object to be positioned is provided, and each of the rotors is directly and independently driven to rotate by an electric direct drive motor to position the output shaft rotor in a two-dimensional position and a rotation angle. A complex eccentric precision positioning control device capable of performing a movement position in a two-dimensional plane by X-
Input means for inputting in the Y coordinate system and inputting the rotation angle of the output shaft rotor by angle, and calculating each rotation angle of the eccentric rotor for two-dimensional surface translation and the rotation angle of the output shaft rotor by the input information from the input means. Calculating means, rotation angle detecting means for detecting the rotation angle of each electric direct drive motor, comparing means for comparing the detected value of the rotating angle detecting means with the calculated value of the calculating means, and a signal from the comparing means, A composite eccentric precision positioning control device comprising a motor drive circuit for driving each electric direct drive motor.