JPS59128615A - Method for controlling position of rotary shaft - Google Patents

Abstract

PURPOSE:To move and stop a rotary shaft to/at an objective position rapidly by executing prescribed stop controlling when the 2nd command value is inputted after completing the stop controlling at the fixed position by the 1st command value. CONSTITUTION:A detector 101 outputting a one-revolution signal RP every one revolution and a position pulse PP every revolution of a prescribed angle and a current position counter 107 counting up the position pulses PP are connected. When the 2nd command value ORCM2 is inputted after completing the stop controlling at the fixed position by the 1st command value ORCM1, the command value ORCM1 is set up on the counter 107. Subsequently, a DA converter 111 is driven on the basis of the deviation ER between the command value ORCM2 and the contents of the counter 107 to control the stop of a motor 100. Thus, the rotary shaft can be moved and stopped to/at an objective position rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary shaft position control method for controlling the main shaft of a machine to stop at a predetermined vertical angle position, and in particular,
The present invention relates to a rotary shaft position control system that allows i-determining.

For example, in an NC machine tool such as a lathe, it is necessary to control the main spindle to stop at a plurality of rotation angle positions during thread cutting work.

In order to control the spindle to stop at a predetermined rotation angle or a fixed position, the following position control method has conventionally been adopted.

Oriental silane command 0 CM which is a fixed position stop command
When I arrives, the AC motor command becomes the speed command VCMD.
Switches from to low speed command (JVCM). In the case of a stopped father-flow motor, the low speed command OVCM is immediately given. This causes the AC motor to rotate at low speed. The AC motor rotates and reaches the absolute origin AO. Then, a one-rotation signal RP is generated from the detector. Generally, the absolute origin AO of the pick is coincident with the rising or falling position of the one-rotation signal.

This absolute origin AU is set corresponding to the mounting position of the detector. This one rotation signal sets the amount of rotation from the absolute origin AU in the current position counter. Referring to Figure 1, the above-mentioned absolute origin AO is usually different from the planned mechanical origin MO due to an error in the installation of the detector, so first, let us first compare the absolute origin AO and the mechanical origin MO. The rotation amount Zl with respect to the target position CA is calculated, and the rotation amount Z2 with respect to the target position CA is determined from the machine origin MO.
Calculate using as the starting point. Therefore, the current position counter is set to (ZI+z,)75t. Thereafter, as the AC motor rotates due to the low speed command, the contents of the current position counter are subtracted by the position pulse from the detector, and when the contents of the current position counter become zero, the low speed command is turned off and the contents of the current position counter are subtracted. It is converted by a DA (digital-to-analog) converter and applied to the AC motor.

Assuming that the current position counter value is n (for example, 40915), the A converter is set to output zero at n/2 (for example, 2048), so when the current position counter value is zero, the speed is low. The maximum voltage of the DA converter equal to the command is output. Hereinafter, I) As the AC motor is rotated by the output of the A converter, the content of the current position counter is subtracted by the device pulse made up of the detector, thus decreasing the output of the DA converter and increasing the current position counter. When the content becomes n/2, the output of the DA converter becomes zero and the flow motor stops. This makes it possible to stop at an arbitrary target position 1δ.

In this conventional position control method, by subtracting a counter, the command is switched from a constant low speed command to a position control command that decreases according to the contents of the counter, and the AC motor can be stopped according to the contents of the counter, so the switching is smooth and the speed can be reduced. Since it decreases smoothly, high-speed and highly accurate positioning becomes possible. However, as shown in FIG. 1 (13), the target position CA
To stop moving to the next target position CBK after stopping at
Since the same control is performed after the motor rotates and generates a one-rotation signal, it is not possible to stop the AC motor in position unless it rotates one revolution or more, which results in unnecessary rotation of the AC motor, making it impossible to stop the movement at high speed. There was also a loss of energy.

Therefore, an object of the present invention is to provide a rotary shaft position control system that can quickly stop at a target position after such a stop.

Hereinafter, the present invention will be explained in detail according to examples.

FIG. 2 is a block diagram of one embodiment of the present invention.
00 is a motor, which can be either AC or DC.
A detector 101 is directly connected to the shaft of the motor 100 and generates a position pulse P every time the motor 100 rotates at a predetermined angle.
P is a circuit that outputs one rotation signal RP for each rotation of the motor 100, 102 is a quadruple circuit, generates a pulse PS with a frequency four times the position pulse PP, and 103 is a speed control circuit. In order to control the speed of the motor 100 according to the command speed, it has a speed control loop and a current control loop. 104 is an origin command setting device, which sets the above-mentioned rotation amount Z1 as a binary origin command. thing, 105
106 is a receiver which receives the moving rotation amount from the machine origin MO given from the NC, etc., and 106 is an adder that combines the rotation amount Z1 of the origin command setter 104 and the command rotation amount from the receiver 105. 107 is a current position counter; 107 is a reversible counter with a capacity n (4096); 108 is a switching circuit; 108 is a switching circuit; In response to the orientation change command ORCM1, a low speed command is issued, and in response to the one rotation signal, the contents of the adder 106 are set in the counter 107 to subtract the pulse PS, and in response to the second orientation change command ORCM2, the content of the adder 106 is set in the counter 107. vessel 106
109 is a position deviation circuit which sets the contents of the adder 106 and the current position error circuit 107 when AN1 is opened. 110 is the origin shift circuit, which outputs the positional deviation E of the contents, and gate A.
When N2 is opened and the origin shift number n/2 is input, it calculates E+n/2 and outputs the deviation E)t. 111 is a DA converter, and the output is zero at Sl, n/2. , n or O, which generates maximum output, 112
is a synthesis circuit, 115 is a switch control circuit,
Each switch SW1. SW2 and SW5 are turned on/off controlled, and 114 is a register in which the origin shift number n/2 is stored.7 Next, the operation of the embodiment configuration shown in FIG. 2 will be explained as follows.
First, if the motor 100 is rotating at high speed, the switch control circuit 113 closes the switch SW3, and the corresponding speed command VCMD is set to the switch SW3 and the synthesis circuit 11.
2 to the speed control circuit 103, and the motor 100
is rotating at a speed according to the speed command VCMD.

■Orientation command to switching circuit 108 CM1
arrives, the switching circuit 108 switches the switch control circuit 11
3, the switch control circuit 113 turns off the switch SW3 and turns on the switch SW2.

As a result, the orientation speed [OVCM is sent to the speed control circuit 103 via the switch SW2 and the synthesis circuit 112, and the motor 100 rotates at the orientation speed. When the motor 100 is rotating at high speed, it is decelerated to the orientation speed, and when it is stopped, it is accelerated to the orientation speed.

■When the motor 100 rotates in this manner and reaches the absolute home position, the detector 101 outputs one rotation signals H and P, and the switching circuit 108 sets the contents of the adder 106 (Zl + Z2) in the current position counter 107. Ru. The adder 106 is connected to the origin command setter 1040 rotations 1itZ1 and the receiver 10.
Since the command amount Z2 from the machine origin MO to the target position from 5 is input, the contents of the adder 106 are (Z1+2
4). (See Figure 3 (5)). Furthermore, the switching circuit 108 issues a subtraction command DE(
When the motor 100 is rotating in the reverse direction, a machining command IN) is given, and the pulse PS obtained from the detector 101 and the quadruple circuit 102 of the motor 100 is subtracted. According to the subtraction, the current position counter 107 becomes zero, and further from Rei (n-1)
When this happens, an overflow pulse OF'P'& is generated and input to the switch control circuit 113, which turns off the switch SW2 and turns on the switch SW1.

■This causes the contents of the counter 107 to be changed to the position deviation circuit 1.
09, it is applied to the DA converter 111 via the origin shift circuit 110. That is, since AND gates AN1 and AN2 are not open, these gates AN1 . Since the input from AN2 is zero, the contents of the counter 107 are passed through. At this time, the output of the DA converter 111 is set so that it becomes zero when the input is n/2 and becomes the maximum voltage when the input is n or O, and this maximum voltage is determined by the orientation speed command O.
Since it is set to the same voltage as VCM, switch SW
Even if switch SW1 is turned off and switch SW1 is turned on, there is no change in the applied voltage, so switching to the position loop is performed smoothly. As a result, the voltage of the DA converter 111 according to the content of the digital rank 107 is applied from the synthesis circuit 112 to the speed control circuit 103, and the speed of the motor 100 is controlled.

■Since the counter 107 is subtracted by the pulse PS generated by the rotation of the motor 100, the DA converter 111
The output of the motor 100 is sequentially decreased and the motor 100 is also decelerated. When the counter 100 becomes +1/2, 1) the output of the A converter 111 becomes zero, υ, and the motor 100 stops. That is, as shown in FIG. 6 (5), from the target position CA to n
/ Stops at position CA after two rotations.

In this way, the first orientation command ORCM1
Accordingly, it is possible to stop at the absolute address position from the absolute origin AO or the mechanical origin MO, high-speed positioning is possible, and its accuracy is also low.

Note that the operation up to this point is the same as the conventional one.

Next, when the machining at the stop position CA is completed and the robot moves to the next target position CBK, the second orientation command 01tCM2 is manually input to the switching circuit 108. The above-mentioned contents (Zl + Z2) of the adder 106 are set in the counter 107 in response to a set command from the switching circuit 10B. That is, the address of the target position CA (the current position of the motor 100) is set in the current position counter 107. Furthermore, switching circuit 108 opens AND gates AN1 and AN2. Accordingly, the position deviation circuit 109
subtracts 8f of the current position counter 107 from the contents of the adder 106 and outputs the fitfA difference ER. In this case, since the contents of the adder 106 and the current position counter 107 are the same, the position error El(.

is zero. The position error E1 (is input to the origin shift circuit 110, the origin shift number n/2 of the register 114 is added, and the position error E, 1 (, (=El (, +n/2) is
1 force is applied.

The position error El-L is converted into an analog voltage by the DA converter 111, but since EI'L is zero, E cylinder n/
2, the output of the DA converter 111 is zero, and the motor 100 does not rotate.

(2) When the rotation 412s from the NC to the target position CB from the machine origin AO is input to the receiver 105, the adder 106 adds the rotation amount Z1 of the origin command setter 104 and this command iZs. As a result, the content of the adder 106 becomes (Z1+Zs), so the output ER of the position error circuit 109 becomes (Zs Z2), and therefore the target position C
This corresponds to the relative positional deviation between B and target position CA. .

This position error E11. is n/2 in the origin shift circuit 110
It is added and output as ER, and the DA converter 111
outputs an analog voltage corresponding to this, and the synthesis circuit 112
The speed control circuit 105 is caused to rotate the feed motor 100 via the speed control circuit 105.

■Detector 101.4 times circuit 1 due to rotation of motor 100
02 signal PS is output. Current position counter 1
07, the switching circuit 108 outputs an addition command IN (motor 1
Since the subtraction command DB) is given when 00 rotates in the reverse direction, the counter 107 adds the pulse PS, so its contents increase. Therefore, the output El of the position error circuit 109
(, decreases.

That is, the motor 100 is controlled so that the current position always follows the command amount.

This output El (is a 19-point shift N path and output 1.:a<=
1.:1ken/2) and is input to the DA converter 111, converted to an analog voltage, and given to the speed control circuit 105 via the synthesis circuit 112 to control the speed of the motor 100.

In this way, the motor 100 decelerates, and when the position error ER becomes zero and the output of the J)A converter 111 becomes zero, the motor 100 stops. This stop position is shown in Figure 3 (B)
It is B.

Further, when the position error BR becomes n/2 or more, the origin shift circuit 110 becomes n J-J, outputs a carry or borrow, inputs it to the switch control device 116, turns on the switch 8W2, and turns on the switch 8W1. 'f<turn off.

Therefore, the orientation command speed OVCM is input to the speed control circuit 103 via the synthesis circuit 112, and the motor 1
Control the speed of 00. The pulses PS generated by the rotation of the motor 100 are added by the counter 107, the position error ER, decreases, and when ER, becomes n/2 or less and no carry or borrow output is generated from the origin shift circuit 110, switch control is performed. Device 113 is switch SW2
is turned off, and switch 8W1 is turned on. For this reason, from now on,
The same control as described in (2) above is performed and the motor 100 is controlled to stop (1), thereby making it possible to index the increment without increasing the bit resolution.

On the other hand, when the first orientation command ORCM1 arrives again, the stop control is performed using the absolute addresses (■ to ■) described above, and the second orientation command ORCM2 is issued.
When , the control to stop the indexing of increments based on the above-mentioned relative deviations is performed.

As explained above, according to the present invention, when the first command is generated, the first command value is set in the counter, the position error from the motor detector is subtracted, and the content of the counter is set to the position error. Since the output is output as , and the motor is driven, it is possible to control the stop based on the absolute address and achieve accurate stop positioning at high speed. The second command is generated, the first command value, which is the current position of the motor, is set in the counter, and the motor is driven based on the deviation from the second command value, that is, the relative address, so the shortest time is possible. This also has the effect of allowing incremental drive to the target position.

In addition, the counter operates to generate an absolute deviation in response to the first command, and generates the current position in response to the second command, so the configuration does not become complicated. It also has an excellent practical effect of being able to configure functions at low cost and in a small size.

Although the present invention has been described with reference to one embodiment, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made in accordance with the spirit of the present invention. It is not something to be excluded.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional position control system, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the operation of the configuration shown in FIG. In the figure, 100...Motor, 101...Detector, 10
6... Adder, 107... Current position counter, 10
9...Position deviation detection circuit, 111...DA converter. Patent applicant Fanuc Co., Ltd. Agent Patent attorney Minoru Tsuji and 1 other person Residence Figure 1 (A) (B) (A)
rB)

Claims (1)

[Claims] a detector that outputs a one-rotation signal every time the motor rotating the rotary shaft rotates once, and a position pulse every time the motor rotates by a predetermined angle;
It has a counter that counts the position pulses of the detector and a DA converter that converts the digital value into an analog value.
A command value is set for the motor, and a command speed corresponding to the contents of the counter is given to the motor from the DA converter to control the motor to stop.When a second command arrives, the first command range is set to the meditation counter and the second command is set. A rotary shaft position control method characterized in that a 9DA converter is driven to control a ward motor to stop based on the deviation between the output value of the counter and the content of the counter.