JP2770024B2 - Home position return device for automatic control machine tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in an origin control device for an automatically controlled machine tool. In particular, the improvement of the home position return device for automatic control machine tools that operates during the period from turning on the power until the main shaft makes one revolution, and the relationship between the mechanical origin and the control origin is cut off due to the high speed of the main shaft rotation. The present invention relates to an improvement of the home position return device for an automatic control machine tool that operates again when the speed of the spindle decreases after the operation.

[Conventional technology]

In an automatic control machine tool, particularly an NC machine tool, it is necessary that the coordinate origins of a control system such as an NC (microcomputer) system and a mechanical system match, or that a fixed offset is maintained.

Therefore, in the prior art, at least before starting the position control, the two are made to coincide with each other, or the two are made to move while maintaining a fixed offset. I say. In many cases, the origin return step refers to the relative position between the tool and the table, but the present invention relates to the angular position of the main shaft that rotates the tool.

[Problems to be solved by the invention]

The home position return device according to the related art relating to the angular position of the main shaft for rotating the tool has a drive mechanism and an electric control mechanism dedicated to home position return, as in the case of other axes, and is structurally and mechanically. It is complicated and operationally complicated. Especially,
The need for a motor dedicated to home position return is a major drawback, and there has been a demand for the development of a home position return device for an automatic control machine tool using a spindle as a drive means.

An object of the present invention is to meet this demand and to provide an origin returning device for an automatic control machine tool using a spindle as a driving means.

[Means for solving the problem]

The above purpose is for the spindle motor driving the spindle (100)
A spindle motor speed detection means (102) for detecting the speed of the spindle motor (100); and a spindle motor speed detection means (1
02) The spindle motor speed (V) detected and the speed command signal (V _c1 ) given from outside, or the position command signal (P _C ) given from outside and the offset between the mechanical system and the NC control system. A spindle motor speed control means (103, 104, 105) selectively operating based on a speed command signal (V _c2 ) issued by a position gain generation means (PG) based on the sum, and the spindle motor A main shaft angle position detecting means (101) for detecting an angular position of (100) and generating an incremental angular position signal and one rotation signal; an up / down counter (108) for counting the incremental angular position signal; A latch (109) for latching the count of the up / down counter (108) based on one rotation signal generated by the main spindle angular position detecting means (101), and an offset between a mechanical origin and a control origin. In the step of detecting and storing the main shaft motor (10 to the position of the mechanical origin
When 0) rotates, the non-volatile memory (111) that stores the contents of the up / down counter (108) as an offset value in response to the one rotation signal matches the mechanical system origin with the control system origin. In the step, under the condition that the origin return command signal and the speed of the spindle motor (100) are low and the speed command signal (V _c2 ) exists,
In response to the rotation signal, the machine origin data stored in the nonvolatile memory (111) is input, and a position command signal (P _C ) given from the outside and the nonvolatile memory (11
1) The position gain generating means (PG) is provided with a position control means (106) for generating a speed command signal ( _Vc2 ) based on the sum of the offset value stored in 1). This is achieved by a home position return device.

Change to

[Action]

In the home return device for an automatic control machine tool according to the present invention, after the automatic control machine tool is installed, the difference between the mechanical origin and the control origin is detected only once and stored in the nonvolatile memory (111). After that, when the home position return command condition is satisfied, the position command (P _C ) is stored in the non-volatile memory (111) instead of the position command (P _C ) given from outside. The sum with the offset value is applied to the position control circuit (106). As a result, the spindle motor (1
00) is started, and one rotation is completed, or when the spindle is once decelerated to a certain speed after the speed has been increased once, the origin can be automatically returned to the origin.

〔Example〕

Hereinafter, an origin control device for an automatically controlled machine tool according to an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1, reference numeral 100 denotes a spindle drive motor, and 101 denotes a spindle angular position detection for generating an incremental angular position signal representing a change in a minute angular position of the spindle and one one-rotation signal for each rotation. Means. Reference numeral 102 denotes a spindle motor speed detection unit that detects the speed of the spindle motor 100.The spindle motor speed signal V detected by the spindle motor speed detection unit 102 is input to the speed control device 105 together with the speed command signal _Vc1. As a speed deviation signal, the signal is input to the current control circuit 104 together with a signal representing the current of the spindle motor 100, and is used as a power command signal, input to the power amplifier 103, amplified there, and drives the spindle motor 100. .

106 is a position control device, and the sum of the position command signal P _C or position command signal P _C and the offset value is input and the content of the up-down counter 108 to be described later, the speed command signal and amplifies the deviation having a position gain generator PG for generating the V _c2. Reference numeral 107 denotes a quadruple circuit, which is a quadruple cycle circuit for multiplying the main spindle incremental angular position signal detected by the main spindle angle position detecting means 101 in a quadruple cycle. 108
Is an up / down counter for counting the output signal of the quadruple cycle circuit. The up-down counter 108
Is cleared by a clear signal, and is input to the position control circuit 106 by one rotation signal generated by the main shaft angle position detecting means 101. Reference numeral 109 denotes a latch, which inputs the contents of the up / down counter 108 to a nonvolatile memory 111 that stores machine origin data. Note that the latch 109 is also cleared by the clear signal.

Incidentally, SW ₁ is first Q of the flip-flop circuit FF ₁ is in contact with 2 side when the H, which is the first switch Q is in contact with the 1 side when the L. Then, when Q is on the second side, the speed command _Vc2 issued by the position control circuit 106 is supplied to the speed detection circuit. COMP is a comparator, and the spindle motor speed detecting means 102
Is compared with the reference voltage _VRE, and an output signal is issued when the spindle motor speed is equal to or less than a predetermined value. AND is an AND circuit.
Operating condition that the three parties is given at the same time one rotation signal and the output signal and the main shaft angle position detecting means 101 of the MP emitted, along with operating the first flip-flop circuit FF _1, initial setting off And the second flip-flop circuit FF ₂ via the third switch SW ₃ which is normally on.
To work. Note that the first flip-flop circuit FF ₁
Is cleared by the clear signal, the second flip-flop circuit FF ₂ is cleared by the homing completion signal or clear signal. 111 is a nonvolatile memory for storing the machine zero data, as the sum of the position command P _C, is input to the position control circuit 106.

The second switch SW ₂ is connected to a second flip-flop circuit FF ₂
Q contacts the 2 side when the H of, Q is is a second switch contact to one side when the L, the position command P _C is through the second 1 side contact of the switch SW _2, the position The signal is input to the control circuit 106.

When the origin return command signal is issued, the signal generated by the AND circuit AND is applied to the third switch SW ₃ and the second flip-flop circuit FF ₂ and position control circuit 106 via the.

Next, a description will be given of a process of storing the position offset in the nonvolatile memory as machine origin data when there is an offset between the position of the one-rotation signal and the position of the machine origin during the machine adjustment.

FIG. 2 is a flowchart of a process of storing the position offset in the nonvolatile memory as the machine origin data when there is an offset between the position of one rotation signal and the position of the machine origin at the time of adjustment after the installation of the machine. .

The third switch SW ₃ is leave off, turning on the power. 1st switch SW ₁ turns on 1 side (speed loop side)
To advance, the second switch SW ₂ also left on (position command side) 1 side.

The latch 109 and the counter 108 first flip-flop circuit FF ₁ and the second flip-flop circuit FF ₂ clears.

 Input a low speed command to start low speed operation.

 Input the home return command signal.

When a single rotation signal is input while the spindle motor is rotating at low speed and the comparator COMP is H, an AND circuit A
ND operates, the first flip-flop circuit FF ₁ Q becomes H.

Here, the first switch SW ₁ to 2 side (position loop side)
To When the spindle motor 100 rotates to the position of the mechanical origin, the contents of the counter 108 are latched.

The latched value is used as an offset in the nonvolatile memory 11.
Remember in 1.

With the above steps, the storage of the offset information in the nonvolatile memory 111 is completed.

Next, a description will be given of a process of returning to the origin during a normal operation.

FIG. 3 is a flowchart of a process of returning to the origin during a normal operation.

The third switch SW ₃ is leave off, turning on the power. 1st switch SW ₁ turns on 1 side (speed loop side)
To advance, the second switch SW ₂ is left on the 2-side (homing side).

Counter 108 and the first flip-flop circuit FF ₁ and the second
To clear a flip-flop circuit FF ₂ of.

A speed command signal is input, and a normal operation (cutting operation) is executed based on a speed loop.

Next, in performing the home position return, the low speed command signal is input to rotate the spindle motor 100 at a low speed.

When a one-time rotation signal is input in a state where the spindle motor 100 is decelerated and the comparator COMP is at H, the AND circuit AND operates to operate the Q of the _first flip-flop circuit FF1.
There becomes a H, this time, the first switch SW ₁ is a position loop control to operate because there 2 side. Although in the second flip-flop circuit FF ₂ of Q is also H, this time, the second switch SW ₂ is in the 2-side, non-volatile memory 111
The machine origin data stored in the
Is input to the 6 and homing completion signal is issued when the spindle motor 100 to the mechanical origin is rotated, the second flip-flop circuit FF ₂ is cleared, the Q becomes L, the second switch SW ₂ is 1 Can be switched to the side.

The origin return operation is completed by the above steps, and thereafter, the position command given from the outside is corrected by the offset from the mechanical origin, and the position control is continued.

〔The invention's effect〕

As described above, in the home return device for an automatic control machine tool according to the present invention, after the machine is installed,
Only once, the offset value between the mechanical system origin and the control system origin is detected and stored in a non-volatile memory. After that, when the origin return condition is satisfied, an externally applied position command is output as described above. The home position is returned by correcting only the offset of the main shaft, so during the period until the main shaft motor starts and completes one rotation, or when the main shaft has once decelerated and then decelerated to a certain speed. To
Automatic home return can be performed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an origin control device for an automatically controlled machine tool according to an embodiment of the present invention. FIGS. 2 (a) and 2 (b) show the positions of one rotation signal and the position of the machine origin when there is an offset in the machine adjustment of the origin control device for an automatic control machine tool according to one embodiment of the present invention. FIG. 4 is a process chart of storing an offset as non-volatile memory as machine origin data. FIGS. 3 (a) and 3 (b) are process diagrams for returning to the origin during a normal operation of the origin control device for an automatically controlled machine tool according to one embodiment of the present invention. 100 spindle motor, 101 spindle angle position detecting means, 102
… Spindle motor speed detection means, 103 spindle motor speed control means, 104 spindle motor speed control means, 105 spindle motor speed control means, 106 position control means, 107
Quadruple circuit, 108 up / down counter, 109 latch, 111 nonvolatile memory, P _C position command signal,
V _c1 , V _c2 ... speed command signal, V ... speed signal, V _RE ...
Reference voltage.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23Q 15/00 309

Claims (1)

(57) [Claims] 1. A spindle motor (100) for driving a spindle, a spindle motor speed detection means (102) for detecting the speed of the spindle motor (100), and a spindle for detecting the spindle motor speed detection means (102). The motor speed (V) and a speed command signal (V
_c1 ) or an externally _supplied position command signal (P _C )
Spindle motor speed control means that operates selectively based on a speed command signal (V _c2 ) generated by a position gain generation means (PG) based on the sum of the offset of the mechanical system and the NC control system. (103), (104) and (105); main shaft angle position detecting means (101) for detecting an angular position of the main shaft motor (100) to generate an incremental angular position signal and one rotation signal; and the incremental angular position signal. An up-down counter (108) for counting the number of rotations; a latch (109) for latching the count of the up-down counter (108) based on one rotation signal generated by the main shaft angle position detecting means (101); In the step of detecting and storing the offset between the motor and the control system origin, when the spindle motor (100) rotates to the position of the mechanical origin, the up-shift is performed in response to the one rotation signal. In the non-volatile memory (111) for storing the contents of the down counter (108) as an offset value, and in the step of matching the mechanical system origin and the control system origin, the origin return command signal and the speed of the spindle motor (100) are adjusted. Under the condition that the speed is low and the speed command signal (V _c2 ) is present, the machine origin data stored in the nonvolatile memory (111) is input in response to the one-turn signal, and given from outside. The position gain generating means (PG) based on the sum of the position command signal (P _C ) received and the offset value stored in the nonvolatile memory (111).
Control means (106) for generating a speed command signal (V _c2 )
A home position return device for an automatically controlled machine tool, comprising: