JP2824649B2 - Spindle controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a spindle control device that controls the positioning of a spindle of a machine tool.

(Prior Art) An ordinary NC lathe or the like is provided with an orientation function for stopping a spindle at a fixed rotation angle position in order to perform automatic tool change for a spindle on which a tool is attached and detached. Furthermore, depending on the type of machining, it is necessary to position the cutting edge of the tool at a predetermined angle when the spindle is stopped, so the spindle motor is provided with a positioning control function. In this case, a pulse coder for position detection attached to the spindle is used, but in order to stop at a predetermined position by spindle orientation control, the position of the spindle must be accurately detected based on the reference position of the pulse coder. No.

(Problems to be Solved by the Invention) Generally, the spindle is directly connected to the pulse coder or connected in a 1: 1 relationship by a gear or a timing belt, but the mechanical origin of the spindle and the reference position of the pulse coder are not always accurate. In the past, these deviations in the position were not matched when the NC program was created, so that the amount of shift of the reference position was reflected in the command data every time the program was executed. Had to be changed, or in the case of an already created NC program, the machine tool axes had to be adjusted to correspond to the set values. Therefore, there has been a problem that the work of changing the data and the work of adjusting the origin are cumbersome and not easy.

The present invention has been made in order to solve the above-described problems, and has a spindle control device capable of easily correcting reference positions of a spindle and a pulse coder when performing tool positioning control using a spindle motor. It is intended to provide.

(Means for Solving the Problems) A pulse encoder coupled to the main shaft, having a position control loop, outputting a rotation angle amount of the main shaft, outputting a one-rotation signal output every one rotation of the main shaft. A spindle control device provided with an orientation control means for controlling the position of the main shaft by an output signal from the main shaft and stopping the main shaft at a desired rotational position, the main shaft being rotationally driven by a spindle motor, and the rotation of the main shaft for the pulse encoder. When the rotation means for storing the rotation angle of the spindle in a section where the spindle reaches the origin after one rotation signal position is issued, and target position data for instructing the stop position of the spindle are added to the orientation control means, After the one-rotation signal position of the pulse encoder stored in the storage means is issued with respect to the target position data, the spindle is restored. Addition means for adding the rotation angle amount of the spindle in the section reaching the point, drive control means for controlling the rotation angle of the spindle by a position control loop by a value obtained by adding the target position data and the rotation angle amount of the spindle, A spindle control device characterized by comprising:

(Operation) In the spindle control device of the present invention, the deviation between the mechanical origin of the spindle and one rotation signal is stored as a parameter in the position control loop, so that the deviation of the reference position in the position control loop can be reduced to 1 The correction can be made over the rotational position.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the overall configuration of a position control system including an orientation circuit. The NC device 1 includes a spindle servo unit 3
Supplies necessary control information to the spindle motor 4
The rotation of the spindle is controlled at a predetermined command speed by the spindle servo unit 3, and the orientation of the spindle is controlled by an orientation circuit 5. The spindle orientation function is performed by a position control loop of the spindle 7 having position detecting means such as a pulse coder 6.
Is stopped at a constant rotation angle position, and a positioning signal (ORCM) for instructing positioning control is detected, and the rotation of the spindle 7 based on the rotation angle data given with reference to the origin position.
The tool 8 attached to is stopped. The spindle motor 4 is connected to the main shaft 7 by a gear or a belt, and the main shaft 7 is directly connected to the pulse coder 6 or connected in a 1: 1 relationship by a gear or a timing belt. The position information of the pulse coder 6 is input to the NC device 1 via the orientation circuit 5, and based on this, the NC device 1 forms an index signal (INDX) for instructing positioning control.

The orientation circuit 5 includes a pulse coder 6
A storage area for storing a difference signal corresponding to a difference between one rotation signal position and the mechanical origin of the spindle 7 is provided. Further, a terminal CNC of the orientation circuit 5 is for receiving a 12-bit binary signal (D11 to D0) as an external command signal of the stop position, and this terminal CNC is directly connected to the high-power sequence circuit 2. The terminal CNA
Is connected to the pulse coder 6 to form a position control loop, and the terminal CNB is connected to the NC device 1.

FIG. 2 shows a procedure for correcting the reference position of the pulse coder based on the difference signal.

The main shaft 7 and the pulse coder 6 having the above configuration are shown in FIG.
As shown in the figure, it is assumed that the pulse coder 6 is connected by the belt 9 and the reference position of the pulse coder 6 is shifted by "a" pulses. S is a mechanical origin, and P is a detection point of one rotation signal. In this case, "a" is an unknown value at first, and in order to detect it, first, spindle orientation control is performed, and the spindle 7 stops at the point where the pulse coder 6 detects one rotation signal.

Next, the spindle 7 is rotated by the spindle motor 4 until the spindle 7 reaches the mechanical origin S. After detecting the previous one rotation signal, the number of pulses "a" generated from the pulse coder 6 is used as the position correction information as the orientation correction information. The data is read into a predetermined storage area of the circuit 5. (FIG. 2B).

Thereafter, the position increment data indicating the stop position and the position correction information are added. According to this information, the angle to be rotated in a predetermined direction is determined by the spindle motor 4.
In this case, the spindle 7 can be rotated to the target position that has been accurately instructed (FIG. 9C).

While the gist of the invention has been described with respect to the specified embodiment, it is apparent that various modifications and alterations of the invention based on the above description are possible.

(Effects of the Invention) As described above, according to the present invention, the difference between the mechanical origin of the spindle and the one-rotation signal is stored as a parameter in the position control loop, so that a tool using the spindle motor can be used. A spindle control device capable of easily correcting the reference position of the spindle and the pulse coder when performing the positioning control of the spindle.

Then, without changing the data on the stop position affected by the shift amount in the NC program, the deviation of the reference position can be corrected, and the belt connecting the main shaft and the pulse coder is passed over the belt. In addition, accurate operation by the existing NC program can be performed without performing the alignment.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a position correction method. 1 ... NC device, 3 ... Spindle servo unit, 4 ...
... Spindle motor, 5 ... Orientation circuit,
6: pulse coder, 7: spindle. 9 ... belt.

Continuation of the front page (56) References JP-A-59-191613 (JP, A) JP-A-61-103757 (JP, A) JP-A-56-102449 (JP, A) JP-A-60-120403 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G05D 3/12 B23Q 5/20

Claims (1)

(57) [Claims] An output signal from a pulse encoder coupled to the main shaft is provided, having a position control loop, outputting a rotation angle amount of the main shaft, outputting a one-rotation signal output every one rotation of the main shaft. A spindle control device provided with an orientation control means for controlling the position of the spindle and stopping the spindle at a desired rotational position, wherein: a spindle driven by a spindle motor; and a rotation signal position of the pulse encoder by rotation of the spindle. Is issued, and storage means for storing a rotation angle amount of the spindle in a section where the spindle reaches the origin, and target position data for instructing the stop position of the spindle is added to the orientation control means, the target position data From the point at which the spindle reaches the origin after the one-rotation signal position of the pulse encoder stored in the storage means is issued. Adding means for adding the rotation angle amount of the spindle, and drive control means for controlling the rotation angle of the spindle by a position control loop by a value obtained by adding the target position data and the rotation angle amount of the spindle. A spindle control device, characterized in that: