JPH0637883Y2 - CNC grinder equipped with position synchronization controller - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a CNC grinder that grinds a workpiece by fixing it to two headstocks of a master axis and a slave axis.

[Prior art]

Conventionally, grinding is performed by incremental position control in a machine that grinds a workpiece by synchronously controlling it with a CNC grinder having two headstocks. This is because in grinding by this incremental position control, simultaneous control with processing (real-time control) is possible and synchronization accuracy is secured. However, when grinding is performed by the incremental position control, it is necessary to return the origin once after the power is turned on, synchronize with the origin return, and then start the operation.

[Problems to be solved by the device]

On the other hand, there was no CNC grinder that grinds a workpiece by synchronous control with absolute position control. This is because when grinding is performed by absolute position control, the origin position is initially set when the device is assembled, so it is not necessary to return to the origin after turning on the power, but unlike the case of incremental position control, the angle This is because it requires a position detection interval (time) for calculation, cannot perform real-time control, and has a problem in that the position detection interval (time) is coarse and synchronization accuracy cannot be secured during grinding. . The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a CNC grinder that grinds a workpiece by synchronously controlling two headstocks, and then the origin after power-on. Turns on the operation preparation switch without requiring a return
The purpose of the present invention is to provide a CNC grinding machine equipped with a position synchronization control device that enables a synchronous control operation that ensures synchronization accuracy.

[Means for Solving the Problems]

The configuration of the device for solving the above problems has two headstocks of a master axis and a slave axis, and these headstocks are prepared for operation in a CNC grinder that grinds a workpiece by synchronous control by absolute position control. Offset registration means for registering the angle between the offset position of the master axis and the offset position of the slave axis in the state, and the angular difference between the position of the master axis and the position of the slave axis in the constant speed rotation state at predetermined time intervals. The difference detection means for detecting a predetermined number of times, the correction value calculation means for calculating the average value of the angle differences detected by the difference detection means as the dynamic characteristic correction value, and the difference between the angles registered in the offset registration means. Correction synchronization for initially correcting the position of the slave axis and additionally correcting the position of the slave axis based on the dynamic characteristic correction value calculated by the correction value calculation means. And having a control means.

[Action]

In a CNC grinder that grinds a workpiece by synchronously controlling two headstocks of a master axis and a slave axis, the preinstalled angles of the master axis and the slave axis are registered.
In the ready state for operation, the position difference of the slave axis is initially corrected by the angle difference. Further, at the time of grinding, the angular difference between the position of the master axis and the position of the slave axis at every predetermined time is detected, the average value thereof is obtained, and the position of the slave axis is additionally corrected. Since this control is a synchronous control by absolute position control, there is no need to return to the origin after power is turned on, the workpiece is fixed to the two headstocks, the power is turned on, and the servo motor rotation operation is started immediately. After slowing up, the grinding process can be started as soon as the rotation speed becomes constant. In this way, by performing the additional correction in addition to the initial correction of the position of the slave axis with respect to the position of the master axis, it is possible to ensure the synchronization accuracy.

【Example】

Hereinafter, the present invention will be described based on specific embodiments. FIG. 1 is a configuration diagram showing a mechanical configuration and an electrical configuration of a CNC grinding machine provided with a position synchronization control device. Numeral 10 is a bed of a CNC grinder, on which a table driven by a servo motor 16 via a feed screw 17 is provided.
11 is slidably arranged in the Z-axis direction parallel to the spindle axis. On the table 11 is a headstock 12 with a master shaft 13 mounted on it.
And a spindle headstock 15 on which a slave shaft 19 is mounted. The master shaft 13 and the slave shaft 19 are respectively provided with a servomotor 14
And is rotated by the servo motor 24. Then, a workpiece W composed of a crankshaft is fixed by a chuck mechanism (not shown) of the master shaft 13 and the slave shaft 19. A tool base 20 that can move back and forth toward the workpiece W is guided behind the bed 10, and a grinding wheel G that is rotationally driven by a motor 21 is supported on the tool base 20. This tool base 20
Is connected to the servomotor 23 via the feed screw 22, and is moved forward and backward by the forward and reverse rotations of the servomotor 23. The drive units 51, 52, 53, 54 input command pulses from the numerical control device 30 to output servo motors 14, 16, 23, 2 respectively.
It is a circuit that drives 4. Then, absolute encoders (A / E) 55, 56 for detecting the rotational positions of the servomotors 14, 24 as absolute positions are connected, and their output signals are transmitted via the interface 38 of the numerical controller 30.
Inputting to CPU31. The numerical controller 30 is a device that mainly controls the rotation of the control shaft to control the grinding of the workpiece W and the correction of the grinding wheel G. The numerical controller 30 is mainly composed of a CPU 31 for controlling the CNC grinding machine, a ROM 33 storing a control program, and a RAM 32 storing input data and the like. RAM
A machining NC data area 321 for storing NC data is formed in 32. Numerical control device 30 includes other servomotors 14, 16, 23, 24
A drive CPU 36, a RAM 35, and a pulse distribution circuit 37 are provided as a drive system for the. The RAM 35 is a storage device for inputting positioning data of the grinding wheel G, the table 11, the master shaft 13, and the slave shaft 19 from the CPU 31. The drive CPU 36 is a device that outputs the positioning data of the slow-up and slow-down of the control axis feed for machining, the angle of the master axis and the corrected angle of the slave axis to it in a fixed cycle, and the pulse distribution circuit 37 is for pulse distribution. After that, the motion command pulse is sent to each drive unit 51, 52, 5
It is a circuit that outputs to 3,54. A tape reader 41 for inputting data and the like to the CPU 31 via the interface 34 and a keyboard for inputting data
42 and a CRT display 43 for displaying data are connected to each other, and the CPU 31 is further connected to an operation panel 45 for outputting a signal such as a machining start command through an interface (not shown). Next, the operation will be described. First, as shown in FIGS. 2 (a) and 2 (b), the servo motors 14 and 24 are connected to drive the master shaft 13 and the slave shaft 19 when the device is assembled or when the motor is replaced. The offset registration means registers the offset angles of the mounting angles of the absolute encoders (A / E) 55 and 56 as OF _M and OF _S , respectively. When the device is set to data input mode, CP
U31 reads all data required for processing from the tape reader 41 via the interface 34, and NC data area 321
Remember. Next, when the machine is set to grinding mode, first the CP
U31 executes the program shown in FIG. 3 which realizes the correction synchronization control means which is the initial correction of the position of the slave axis. In step 100, it is determined whether or not the driving is ready. Here, in step 100, it is determined whether or not the device is powered on and the operation preparation is ON. If the operation preparation is ON, the routine proceeds to step 102, where it is judged whether or not it is the first flow in this program after the operation preparation is turned ON. Here, when it is the first time after the operation preparation is turned ON, the process proceeds to step 104, and the current position (M) of the master axis 13 and the offset-registered values OF _M , OF _{S of the} master axis 13 and the slave axis 19 are registered. The current position (S) of the slave shaft 19 is calculated from the following equation (S) = (M)-(OF _M -OF _S ) and the slave shaft 19 is rotated to the angle value of (S). The current position (S) of slave axis 19 is assumed. Next, in step 106, the slave shaft 19 is rotationally controlled (referred to as a servo lock) by a difference (OF _M -OF _S ) between the registered angles of the master shaft 13 and the slave shaft 19 (OF _M −OF _S ),
This program ends. In step 102, when it is not the first time after the operation preparation is turned ON, the process proceeds to step 108, and when the rotation command signal for starting the machining is output from the operation panel 45, the step 110 is performed.
Then, the master axis 13 and the slave axis 19 are rotationally controlled by the difference (OF _M -OF _S ) between the registered angles of the master axis 13 and the slave axis 19, and the program ends. Then, in step 108, when the rotation command signal is not output, the process proceeds to step 106 and the program is executed. Next, the CPU 31 executes the program shown in FIG. In step 200, it is determined whether the grinding mode is the synchronous rotation mode. If it is the synchronous rotation mode, the routine proceeds to step 202, where it is judged whether it is within a predetermined time after the slow-up. Here, if it is within the predetermined time after the slow-up, the process proceeds to step 204 which achieves the difference detection means, and the angular difference between the position of the master axis and the position of the slave axis is detected a predetermined number of times at a predetermined time. . The timing of this detection is, for example, 2 ms when the workpiece W reaches constant speed rotation.
Grinding is started at the same time as the detection operation of detecting each value a predetermined number of times. Therefore, no time loss occurs in the grinding process for detecting the angular difference between the position of the master shaft and the position of the slave shaft. Next, when the angular difference between the position of the master axis and the position of the slave axis has been detected a predetermined number of times at a predetermined time, the process proceeds to step 206 which achieves the correction value calculation means, and is detected in step 204. The average of the values for each predetermined time is calculated and used as the dynamic characteristic correction value. Then, after the calculation of the dynamic characteristic correction value is completed in step 206, the process moves to step 208 which achieves the correction synchronization control means for additionally correcting the position of the slave axis, and when the master axis target position is set to the command value. The slave axis target position of is calculated from the dynamic characteristic correction value calculated in step 206 above by the following formula: slave axis target position = master axis target position + dynamic characteristic correction value, and the corrected slave axis target Position synchronization control is performed based on the position and the master axis target position, and this program ends. In step 200, when the grinding mode is not the synchronous rotation mode, the process proceeds to step 210 and the dynamic characteristic correction value is set to zero, that is, the master axis target position and the slave axis target position are set to the same value, Moving to step 208 of, the program is executed. Then, in step 202, when it is within the predetermined time after the slow-up, since the dynamic characteristic correction value of the position of the slave axis with respect to the position of the master axis has been calculated, the process proceeds to step 208 described above. The program is executed. In this way, in the synchronous control by absolute position control, when the power is turned on, the initial difference is corrected by the difference in angle (OF _M -OF _S ) between the master axis and the slave axis registered as an offset, and the rotation speed becomes constant after slow-up. The grinding process can be gradually performed. At the same time, the angle difference between the position of the master axis and the position of the slave axis is detected a specified number of times at a specified time, the average value is obtained as the dynamic characteristic correction value, and the dynamic characteristic correction value is used to quickly add at constant speed rotation. Will be corrected. Therefore, it is not necessary to perform operations such as home return when the power is turned on, and in addition to absolute position control,
It is possible to provide a CNC grinding machine equipped with a position synchronization control device that can secure the synchronization accuracy between the position of the master axis and the position of the slave axis for each predetermined time and can shorten the processing time after the power is turned on. In the above-mentioned embodiment, the timing for obtaining the dynamic characteristic correction value is set within a predetermined time after the slow-up, but other than that, it may be performed when the workpiece is rotating at a constant speed. Furthermore,
The dynamic characteristic correction value may be a calculated value other than the average value, such as an intermediate value between the maximum value and the minimum value.

[Effect of device]

According to the present invention, an offset registration means for registering an angle between an offset position of a master axis and an offset position of a slave axis in an operation preparation state, and an angular difference between a position of a master axis and a position of a slave axis in a constant speed rotation state are set to a predetermined value. The difference detection means for detecting a predetermined number of times per time, the correction value calculation means for calculating the average value of the angle differences detected by the difference detection means as the dynamic characteristic correction value, and the difference between the angles registered in the offset registration means. Since the slave axis position is initially corrected and the correction synchronization control means for additionally correcting the slave axis position based on the dynamic characteristic correction value calculated by the correction value calculation means is provided, this is a characteristic of absolute position control. Of course, it is not necessary to return to the original position after turning on the power, but synchronization accuracy is ensured despite the absolute position control, and there is no need for grinding after turning on the power. Eliminating the Do operation and actuation, etc., it is possible to shorten the total processing time.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a mechanical configuration and an electrical configuration of a CNC grinding machine equipped with a position synchronization control device according to a specific embodiment of the present invention. 2A and 2B are offset angles OF _M of the master axis and the slave axis according to the embodiment.
And explanatory view showing the OF _S. 3 and 4 are flowcharts showing the processing procedure of the CPU used in the apparatus of the embodiment. 10 …… Bed, 11 …… Table 13 …… Master axis, 19 …… Slave axis 14,16,23,24 …… Servo motor 30 …… Numerical controller 51,52,53,54 …… Drive unit 55,56 …… Absolute encoder G …… Grinding wheel, W …… Workpiece

Claims (1)

[Scope of utility model registration request] 1. A CNC grinder having two headstocks of a master axis and a slave axis, and these headstocks grinding a workpiece by synchronous control by absolute position control, wherein the offset of the master axis in a ready state for operation. Offset registration means for registering the angle between the position and the offset position of the slave axis, and a difference for detecting the angular difference between the position of the master axis and the position of the slave axis in a constant speed rotation state for a predetermined number of times at predetermined times. A detection unit, a correction value calculation unit that calculates an average value of the angle differences detected by the difference detection unit as a dynamic characteristic correction value, and an initial position of the slave axis based on the angle difference registered in the offset registration unit. A correction synchronization control means for correcting and additionally correcting the position of the slave axis based on the dynamic characteristic correction value calculated by the correction value calculating means. CN with a position synchronization control device comprising
C grinder.