JP3202528B2 - Rotating speed control device for rotating body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the rotation speed of a rotating body, and more particularly to an apparatus for controlling the rotating speed of a rotating body when processing the outer peripheral surface of a rotating body such as a cam while rotating the rotating body. is there.

[0002]

2. Description of the Related Art A rotational speed control device of this kind is disclosed in
No. 286305. JP-A-3-28
In the apparatus disclosed in Japanese Patent No. 6305, a rotation speed ratio for each arbitrary rotation angle with respect to the average rotation speed of the rotating body is set in advance. The scan time at the current target angle C _U obtained by multiplying the average rotation speed and the rotation speed ratio is multiplied by the scan time. The angle ΔC obtained by this multiplication
When the sum of the current target angle C _U is set as the target angle after scan time.

[0003]

However, Japanese Patent Laid-Open Publication No. Hei 3-2
In the device disclosed in Japanese Patent No. 86305, the rotation speed of the rotating body is controlled based on a target angle obtained by sequentially calculating from the original position, and the actual rotation angle is not always detected. Therefore, the actual rotation angle of the rotating body may not be the target angle for some reason. In this case, the control characteristic of setting the sum of the angle ΔC and the current rotation angle C _U as the target angle after the scan time does not match the appropriate control characteristic at the actual rotation angle of the rotating body. For this reason, the rotation of the rotating body is blurred, and wobbling that lacks smoothness occurs. When the rotation angle of the rotating body returns to the original position, the calculation of the target angle is reset.
The reset control, which is a kind of discontinuous control, becomes an unstable element of the rotation of the rotating body.

In the case where the outer peripheral surface of the rotating body is ground by a grinding wheel, the rotational fluctuation or wobbling of the rotating body causes a relative displacement from the grinding wheel, and good profile grinding cannot be performed.

An object of the present invention is to control the rotation speed of a rotating body with desired control characteristics.

[0006]

According to the first aspect of the present invention, there is provided a rotation driving means for driving a rotating body, and an angle-speed correspondence in which the rotating speed of the rotating body corresponds to the rotation angle of the rotating body. Storage means for storing data; angle detection means for detecting the rotation angle of the rotating body; and a rotation speed corresponding to the detected rotation angle obtained from the angle detection means,
With read based on the speed corresponding data, the predetermined time from the multiplication value of between the read-out speed and Tokoro Ordinary
Calculating the angle the rotary body rotates during the between, and the calculated
Value obtained by adding the angle at which the rotating body rotates to the detected rotation angle
Was constituting the rotational speed control device and a control means for controlling <br/> said rotary drive means as the target rotational angle of the rotating body definitive after between said predetermined time.

In the second aspect of the present invention, the angle-velocity correspondence data is discrete data given at predetermined angular intervals. In the invention of claim 3, the control means is provided with a function of calculating a rotation speed corresponding to the angle detected by the angle detection means by interpolation based on the angle-speed correspondence data.

[0008]

The control means reads the rotation speed corresponding to the detected angle obtained from the angle detection means based on the angle-speed correspondence data. Control means, the read speed and Jo Tokoro
Rotating body rotates and a multiplication value of the inter time between between the stations scheduled
To calculate the angle of rotation of the rotating body.
Is added to the detected rotation angle after the predetermined time.
The rotation driving means is controlled as a target rotation angle of the rotating body to be rotated . Thus, between the actual rotation angle and the target rotation angle,
Even if there is a deviation , the rotation angle of the rotator used for the multiplication always gives a rotation command based on the angle-speed correspondence data of the rotator at that time. The speed control is based on the calculation of the rotation angle according to the characteristic.

According to the second aspect of the present invention, the control means reads the speed corresponding to the detected rotation angle from the angle-speed correspondence data which is discrete data. In the invention according to claim 3, the control means controls the angle-speed correspondence data in order to obtain more accurate data when the angle-speed correspondence data is coarse or when there is no data matching the detected rotational speed in the storage means. The speed corresponding to the detected rotation angle is read from the data by interpolation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a grinding machine will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, a work support 2 is supported on a base 1 by a moving arrangement mechanism (not shown) so as to be movable in the horizontal direction (Z direction) of FIG. On the work support 2, a headstock 3 and a holder 4 are supported side by side in the Z direction. The headstock 3 supports a servo motor type work rotating motor 5, and a work W (a camshaft in this embodiment) can be attached and detached between the spindle 6 driven by the work rotating motor 5 and the holder 4. Supported by The work W is rotated in one direction by the operation of the work rotation motor 5 which constitutes a rotation driving means together with the main shaft 6.

A grindstone table 7 is supported on the base 1 so as to be movable in the vertical direction (X direction) in FIG. A servo motor type moving motor 9 is attached to the base 1. The moving motor 9 rotates the ball screw 8, and the grindstone table 7 moves in the X direction along the ball screw 8 by the operation of the moving motor 9. A grindstone 10 is rotatably supported on the grindstone stand 7 via a support shaft 11. A grinding motor 12 is supported on the grindstone table 7. The rotation of the pulley 13 driven by the grinding motor 12 is transmitted to the pulley 15 on the support shaft 11 via the belt 14, and the grinding wheel 10 rotates in one direction by the operation of the grinding motor 12.

The cam W ₁ on the work W is arranged on the moving path of the grindstone 10 by the moving arrangement mechanism. Grinding wheel 10 rotated by the operation of the grinding motor 12 to the driving direction to grind the outer circumferential surface W ₂ of the cam W ₁ as the rotating body.

The work rotating motor 5 and the moving motor 9 are controlled by a numerical controller NC as a control means. The numerical controller NC comprises a central processing unit CPU for performing various arithmetic processes, a program memory ROM for controlling the operation of the entire apparatus, and a data memory RAM for storing various data. Numerical controller N
C controls the rotation of the movement motor 9 based on the rotation control of the work rotation motor 5.

The data memory RAM serving as storage means stores a predetermined time Δt (for example, 1 ms) and the angle-speed correspondence data shown in FIG. In FIG. 4, θ ₀ to θ _m represent the rotation angle θ of the main shaft 6, and ω _{0 to} ω _m represent the rotation speed ω of the main shaft 6 set corresponding to the rotation angle. FIG.
Represents the profile of the cam W _1, the graph of FIG. 6 represents an example of a desired relationship between the rotational speed (the rotational angle of the words, spindle 6) rotation angle of the cam W _1. Rotation angle of the cam W ₁ is in the main axis angle theta ₀ when the position P ₀ and the grinding wheel 10 on the outer peripheral surface W ₂ of the cam W ₁ is in contact. The position P on the outer peripheral surface W ₂ of the cam W _{1 0} to P ₈ and the grindstone 1
Rotation angle of the cam W ₁ when the 0 and are in contact is set as theta _a through? _H respectively. The data in FIG.
This curve is smoothed and, for example, equally divided into data for each degree.

Encoders 17 and 18 incorporated in the work rotation motor 5 and the movement motor 9 detect the rotation angles of the motors 5 and 9, respectively. This detection information is sent to the numerical controller NC. The numerical control device NC, the rotation angle of the main shaft 6 on the basis of the detection information obtained from the encoder 17 as the angle detecting means (i.e., the rotation angle of the cam W ₁₎ to grasp the detection information obtained from the encoder 18 The movement position of the grindstone 10 is grasped based on. And the numerical controller N
C is the detected angle information obtained from the encoder 17, the pulse signal input from the reference pulse generator 16, the stored predetermined time Δt, the angle-speed correspondence data shown in FIG. 4, and the rotation speed control shown in the flowchart of FIG. The rotation speed of the spindle 6 is controlled based on a program. The reference pulse generator 16 outputs a pulse signal to the numerical controller NC every predetermined time Δt.

The control of the rotational speed of the main shaft 6 by the numerical controller NC based on the flowchart of FIG. 7 will be described below. When a pulse is output from the reference pulse generator 16, the numerical controller NC reads the rotation angle θ of the spindle 6 at the time of the pulse generation based on the detection information obtained from the encoder 17 (step 101). Since the angle-speed correspondence data in FIG. 4 is discrete data, the read rotation angle θ does not always match any of the angle-speed correspondence data. That is, when θ _n and θ _{n + 1} are two adjacent angles among θ _{0 to} θ _m in the angle-speed correspondence data, for example, when θ is in the range of θ _n <θ <θ _{n + 1} Occurs. The numerical controller NC determines whether or not the read rotation angle θ matches any one of the angle-speed correspondence data (step 102).
If the read rotation angle θ does not match any of the angle-speed correspondence data, the numerical controller NC
Performs an interpolation operation based on the read rotation angle θ and the angle-speed correspondence data, and calculates a rotation speed ω (θ) corresponding to the rotation angle θ by this interpolation operation (step 103).

If the read rotation angle θ does not coincide with any of the angle-speed correspondence data, the numerical controller NC determines the rotation angles before and after θ in the angle-speed correspondence data and the corresponding rotation speed. For example, a spline interpolation operation is performed based on the rotation speed ω corresponding to θ.
(Θ) is calculated. This is an interpolation operation.

If the read rotation angle θ coincides with any one of the angle-speed correspondence data, the numerical controller NC determines the rotation speed ω (θ) corresponding to the angle θ in the angle-speed correspondence data. read.

The numerical controller NC multiplies the calculated or read rotation speed ω (θ) by a predetermined time Δt, and obtains a product ω (θ) · multiplied by the rotation speed ω (θ) and the predetermined time Δt.
Value obtained by adding Δt to rotation angle θ [θ + ω (θ) · Δt]
Is used as the next target rotation angle of the spindle 6 in the data memory RA.
It is stored in M (step 104). Next, the numerical controller NC determines the rotation angle [θ + ω (θ) after a predetermined time Δt.
.DELTA.t] is controlled to control the rotation of the work rotating motor 5 (step 105).

When a predetermined time Δt has elapsed since the previous reading of the rotation angle θ (step 106), the numerical controller NC determines whether or not the grinding has been completed (step 10).
7) If the grinding is not completed, the control shown in the flowchart of FIG. 7 is repeated.

Even when a deviation occurs between the actual rotation angle and the target rotation angle due to a delay, disturbance, or the like inherent in the servo system, the deviation is not compensated for and the numerical controller NC is used.
Indicates the rotation speed based on the actual rotation angle of the main shaft 6 and indicates the target rotation angle after a predetermined time Δt. That is, the numerical controller NC controls according to the originally desirable control characteristics represented by the angle-speed correspondence data in FIG. Therefore, never fluctuation of rotation of the cam W ₁ occurs, the rotation of the cam W ₁ is an angle of 4 - the original desirable rotation characteristic representative of a speed corresponding data.

The movement control of the grinding wheel 10, that is, the movement of the movement motor 9
Rotation control is cam W₁Synchronous control according to the cam shape
Must. 8 is the angle-velocity of FIG.
Desirable angle-position correspondence of wheelhead 7 to correspondence data
It is an example of data. The angle in curve D is the angle in FIG.
-Rotation angle θ in speed correspondence data₀~ Θ_mSame as
Yes, the speed of the grinding wheel head 7 corresponds to the rotation speed of the moving motor 9
are doing. Rotation angle θ ₀~ Θ_mAnd the corresponding moves
The angle-speed correspondence data with the rotation speed of the motor 9 is the data
It is stored in the memory RAM. The numerical controller NC
Rotation angle information and movement obtained from encoders 17 and 18
Movement based on angle-speed correspondence data in motor 9
Synchronize the operation of the motor 9 with the work rotating motor 5
To control.

[0024] That is, the movement control of the grinding wheel 10 to perform based on the rotation control of the cam W _1, never displacement caused by fluctuation rotation occurs between the cam W ₁ and the grindstone 10 that rotates at a desired rotational property good grinding of the cam W ₁ is performed.

According to the present invention, the predetermined time Δt, which is an interval for reading the current rotation angle, is made larger in the constant rotation speed region than in the rotation speed change region, or the speed is changed at intervals of the minimum resolution angle of the angle detecting means. Corresponding embodiments are also possible. Alternatively, an embodiment is also possible in which continuous angle-speed correspondence data as shown in FIG. 6 is set as a function, and the rotation speed corresponding to the current rotation angle is calculated based on this function.

[0026]

As described above in detail, according to the present invention, the rotation speed corresponding to the detected rotation angle obtained from the angle detection means is obtained by referring to the angle-speed correspondence data, and the obtained rotation speed is determined by the obtained rotation speed. target values rotary body obtained by adding the angle to rotate the detected rotational angle on time period of the post between the predetermined time
Since the rotation angle is used , the rotation of the rotator has the originally desirable rotation characteristics represented by the angle-speed correspondence data, and the rotation of the rotator can be prevented from rotating and wobbling.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment in which the present invention is embodied in a grinding apparatus.

FIG. 2 is a partially cutaway front view of the grinding device.

FIG. 3 is a control block diagram.

FIG. 4 is a data table diagram showing angle-speed correspondence data on a main shaft.

FIG. 5 is an enlarged view illustrating a contact position of a cam with respect to a grindstone.

FIG. 6 is an angle-velocity interpolation data graph created from the data table of FIG. 4;

FIG. 7 is a flowchart showing a rotation speed control program.

FIG. 8 is a data table diagram showing angle-position correspondence data with respect to the grinding wheel head.

[Explanation of symbols]

5 Work rotation motor constituting rotation driving means, 6 Spindle constituting rotation driving means, 16 Reference pulse generator, 17 Encoder serving as angle detection means, RAM Data memory serving as storage means, NC control Numerical control device as means, W ₁ ... rotating body.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05B 19/4103 B23Q 15 / 00,15 / 08

Claims (3)

(57) [Claims] 1. A rotation driving means for driving a rotating body to rotate, a storage means for storing angle-speed correspondence data in which a rotating speed of the rotating body is made to correspond to a rotation angle of the rotating body, and a rotating angle of the rotating body an angle detecting means for detecting the angle detecting said angle rotation speed corresponding to the detected rotational angle obtained from the means - with reading based on the speed corresponding data, power of the between the read-out speed and Tokoro Ordinary
Calculating the angle the rotary body is rotated from the calculated value during the predetermined time, definitive values rotary member and said calculated by adding the angle of rotation to the detected rotational angle after between said predetermined time rotator
And a control means for controlling the rotation drive means as the target rotation angle . 2. The rotation speed control device for a rotating body according to claim 1, wherein said angle-speed correspondence data is discrete data given at predetermined angular intervals. 3. The rotation of the rotating body according to claim 2, wherein said control means calculates a rotation speed corresponding to the angle detected by said angle detection means by interpolation calculation based on said angle-speed correspondence data. Speed control device.