JPH04283048A - Main spindle positioning system - Google Patents

Abstract

PURPOSE:To position a main spindle in an arbitrary se position located within one full turn of the main spindle by mounting only a one rotation signal detecting mechanism for outputting a signal once each time the main spindle is rotated by one full turn on the main spindle and locating a position and speed detector to a main spindle motor. CONSTITUTION:A main spindle motor is run at a set speed Vo by means of a constant position stop command. The value of a counter to count a pulse generated from a detector to detect the rotation position of the main spindle motor each time a rotation signal is generated once is latched to a latch circuit. When, after the speed of the main spindle motor attains a set speed Vo, a one rotation signal is outputted, values Pc and Pr of the counter and the latch circuit are read, a value (Pc-Pr) is subtracted from a moving amount Po of the one full turn of the main spindle, and a value added by a command stop device Pg is set to an error counter. A main spindle which does not perform control of a position before a position deviation set to the error counter attains T0 is stopped at a set rotation position (a set rotation angle position).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle positioning method for stopping the spindle of a machine tool at a set position within one revolution.

0002

2. Description of the Related Art Various types of spindle positioning systems have been developed for stopping the spindle of a machine tool at a predetermined position. In these conventional spindle positioning systems, the spindle is driven by a spindle motor via a gear or a timing belt.
If the spindle rotation speed and spindle motor rotation speed are different,
A position detector (position coder) and a detector that outputs one rotation signal for each rotation of the spindle are attached to the spindle to control the spindle to stop at a set position (set rotational position within one rotation). .

0003

However, installing a detector for one rotation signal and a position detector for detecting the rotational position on the main shaft side has the disadvantage that the structure of the main shaft becomes complicated.

[0004] Therefore, the object of the present invention is to provide a simple
It is an object of the present invention to provide a spindle positioning method that can position the spindle by installing only a detector that detects only rotation signals.

[0005]

[Means for Solving the Problems] The present invention provides a spindle drive method in which the spindle of a machine tool is driven by a spindle motor via a gear or a timing belt, and the spindle is provided with a one-rotation signal once per one rotation of the spindle. A speed/position detector is attached to the spindle motor, a counter is installed to count the position feedback pulses output from the speed/position detector, and a counter is installed to count the position feedback pulses output from the speed/position detector, and a A latch circuit that latches the value of the counter is provided, and the spindle motor is speed controlled to a predetermined speed set by the spindle fixed position stop command, and when the set speed is reached and the one rotation signal is detected thereafter, the counter Read the value of the latch circuit and the value of the latch circuit from the read counter value, subtract the value obtained by subtracting the value of the latch circuit from the above movement amount for one rotation of the spindle, and then add the set movement amount from the one rotation signal detection position to calculate the position. Input it to the error counter as a deviation and switch from speed control to position control. The above problem was solved by stopping the spindle at the set position when the value of the error counter became "0".

[0006]

[Operation] Only normal speed control is executed on the main shaft motor. Then, when the main shaft fixed position stop command is issued, the main shaft motor is accelerated or decelerated and controlled to a set speed (orientation speed). On the other hand, the above counter counts the position feedback pulses from the speed/position detector attached to the spindle motor, and the above latch circuit has a one-rotation signal output from the one-rotation signal detector attached to the spindle. The value of the above counter is latched every time. Therefore, when it is detected that the set speed, that is, the orientation speed is reached and a one-rotation signal is output, the values of the counter and latch circuit are read, and the value of the latch circuit is subtracted from the value of the counter. The difference obtained at this time is equal to the amount of rotation of the main shaft from the one rotation signal generation position. Then, the amount of movement per one rotation of the main spindle (the amount of movement per one rotation of the main spindle)
By subtracting the above difference from the amount of position feedback pulses generated during rotation, the amount of movement of the main shaft from the current position to the one-rotation signal generation position can be found, and this value is the set stop position. Amount of movement from one rotation signal position (
If the value obtained by adding the set rotational position within one rotation of the spindle is input into the error counter as a position deviation, and the speed control is switched to position control, the value of the error counter for the spindle motor will become "0". When the value of the error counter reaches "0", the spindle motor stops rotating, and the spindle stops at the set rotational position, indicating that the spindle has been positioned.

[0007]

[Embodiment] FIG. 2 is a block diagram showing a main shaft drive system for carrying out an embodiment of the present invention. Reference numeral 1 indicates a main shaft, and the main shaft 1 is prevented from slipping due to a main shaft motor 4 such as a gear or a timing bell. It is designed to be driven via a transmission mechanism 2 like this. The main spindle 1 also has a one-rotation signal detection mechanism 3 that outputs one rotation signal for each rotation of the main spindle 1.
is installed. This one-rotation signal detection mechanism 3 may be a simple switch that detects a predetermined position of the main shaft and outputs a one-rotation signal.

A speed/position detector 5 is attached to the main shaft motor 4 to detect the rotational speed and rotational position of the motor. 8 is a numerical control device (hereinafter referred to as an NC device) that controls the machine tool, and 7 is a motor control circuit that controls the spindle motor, which is connected to the NC device 8, and the one-rotation signal detection mechanism 2 and the speed - It is connected to the position detector 5, and as described later, it is composed of a speed control section that controls the speed of the spindle motor 4, a position control section during positioning, and a processor, ROM, RAM, etc. for performing various calculations. , the main shaft motor 4 is driven and controlled via a power circuit 6 such as a transistor inverter.

FIG. 3 is a detailed block diagram of the motor control circuit, in which 10 is an error counter for storing position deviation during positioning control, 11 is a transfer function term of position gain Kp, and 12 and 13 are speed control loop terms. These are the transfer function term of the proportional gain K1 and the integral transfer function term, and K2 is the integral gain. Further, 14 and 15 are transfer function terms of the main shaft motor, Kt is a torque constant, and Jm is an inertia. Furthermore, 16 is an integral transfer function term for integrating speed and determining position, and 17 is a term for the pulley ratio (gear ratio) of the transmission mechanism 2, which is a term for converting the rotational position of the motor 4 into the rotational position of the main shaft 1. , indicating that the motor 4 rotates n times and the main shaft 1 rotates M times.

Further, 19 is a reversible counter that counts the position feedback pulse Pf output from the speed/position detector, and 20 is a reversible counter that counts the position feedback pulse Pf output from the speed/position detector 3. This is a latch circuit that latches the value of . Reference numeral 18 indicates a software processing block executed by the processor of the motor control circuit 7. Switches S1 and S2 are shown for convenience; during speed control, switch S1 is set to "OFF" and switch S2 is set to "ON"; during position control during spindle positioning, switch S1 is set to "ON" and switch S2 is set to "OFF". It is said that

First, an overview of the operation of this embodiment will be explained. Normally, the switch S1 is "OFF" and the switch S1 is "OFF".
2 is turned ON, and based on the speed command VCMD sent from the NC device, the speed feedback signal Vf output from the speed/position detector 5 is subtracted from the speed command VCMD to find the speed deviation. Gain K proportional to deviation
The torque command (current command) is obtained by adding the value (12) multiplied by 1 and the value (13) obtained by multiplying the integral multiplier K2 to the value obtained by integrating the speed deviation and drives the main shaft motor 4 via the power circuit 6. do.

On the other hand, when a fixed position stop command is output from the NC device 8, the motor control circuit 7 outputs the orientation speed set by the parameter as the speed command VCMD, and the motor speed becomes the orientation speed, When a one-rotation signal is output from the rotation signal detection mechanism 3, as will be described later, a movement command value to the set stop position is input to the error counter 10, and switches S1 and S are input.
2, switch S1 to "ON", switch S2
Turn OFF, start position control, and set error counter 1.
When the value of 0 becomes "0", a fixed position stop completion signal is output to the NC device 8, and the spindle positioning control is ended.

FIG. 1 is a flowchart of the processing (contents of the software processing 18) executed by the processor of the motor control circuit 7, and the processor executes the processing at predetermined intervals. First, when the power is turned on, flags Fo, which will be described later,
Fe, Fp, and Fv are initially set to "0". Then, when a fixed position stop command is output from the NC device 8, “1
” is determined whether the fixed position stop command flag Fo is “1” (step 100), and if it is not “1”, N
Speed control is performed based on the speed command VCMD output from the C device 8 (step 113). That is, Figure 3
Then, the switch S1 is turned OFF and the switch S2 is turned ON, speed loop processing is executed based on the command speed VCMD and the speed feedback signal Vf, and the spindle motor 4 is driven and controlled via the power circuit 6. Below, the fixed position stop command is N
The processor performs speed control every cycle based on the commanded speed VCMD until the flag Fo output from the C device 8 becomes "1".

On the other hand, when a fixed position stop command is output from the NC device 8 and the flag Fo is set to "1", step 1 is executed.
00 to step 101, it is determined whether the completion flag Fe set when the fixed position stop is completed is "1", and since the completion flag Fe is "0" at the beginning, next, the positioning process is performed. It is determined whether the positioning flag Fp that is set when the process is started is "1" (step 102), and "
If it is not "1" (initially it is "0"), the orientation speed Vo set by the parameter is output and speed control is performed (step 103). Next, when the main shaft motor 4 reaches the above-mentioned orientation speed Vo, "1"
Orientation speed achievement flag Fv set to
is "1" (step 104), and if it is not "1" (initially "0"), the velocity feedback signal Vf detected by the position/velocity detector 5 has reached the orientation velocity Vo. (Step 11)
4) If it has not been reached, the processing for the relevant cycle is ended.

The following steps 100 to 104 and step 114 are performed every cycle, and when the speed Vf of the spindle motor 4 reaches the orientation speed Vo, the process moves from step 114 to step 115, and the orientation speed achievement flag Fv is set to "1", and the register R, which is set to "1" when the one-rotation signal Sg output from the one-rotation signal detection mechanism 3 is input, is set to "0" (step 115), and the processing of the corresponding cycle is performed. end.

From the next cycle, steps 100 to 104 are performed, and since the flag Fv is "1", the process moves from step 104 to step 105, and it is determined whether the register R is "1" or not. , is not "1", that is, if the one-rotation signal Sg is not output after the motor speed reaches the orientation speed Vo, the processing for the period is ended. Also, the value of the above register R is “1”.
”, the value Pr of the latch circuit 20 and the value Pc of the counter 19 are read (step 106). The counter 19 counts the feedback pulses output from the position/speed detector 5, and the value Pc of the counter 19 represents the rotational position of the main shaft motor. Furthermore, the latch circuit 20 latches the value of the counter each time a one-rotation signal is generated, so that when the orientation speed Vo is reached, the register R is set to "0", and the
When the register R becomes "1" due to the rotation signal, the latch circuit 20 stores the value of the counter at the position where the one rotation signal is generated after reaching the orientation speed Vo. The processing cycle shown in FIG. 1 is performed at a sufficiently short cycle compared to the orientation speed Vo, so the value of the latch circuit 20 read in step 106 is the first value after reaching the orientation speed Vo. The value of the counter 19 when the one rotation signal is generated is stored.

Then, the following equation is calculated to determine the amount of movement Ps to the command stop position Pg (the amount of movement from the one-rotation signal generation position within one rotation of the main shaft 1).

Ps=Pa−(Pc−Pr)+Pg
=Pa-Pc+Pr+Pg
(1) In the above equation 1, Pa is the amount of position feedback pulses generated during one rotation of the main shaft 1, and is a value that is uniformly determined once the pulley ratio or gear ratio of the transmission device 2 is determined. Further, the value (Pc-Pr) obtained by subtracting the value Pr of the latch circuit 20 from the value Pc of the counter 19 represents the amount of rotational movement of the main shaft 1 from the current one-rotation signal generation position, and the one-rotation movement amount Pa By subtracting this value (Pc-Pr) from , the amount of movement from the current position to the one-rotation signal generation position can be determined. Furthermore, by adding the command stop position (grit shift amount) Pg to this value, the movement amount Ps from the current position to the command stop position can be determined. Then, the obtained movement amount Ps is set in the error counter 10 as a positional deviation (step 107), and the positioning flag Fp is further set to "1" (step 108).
, start position control. That is, in FIG. 3, the switch S1 is turned on and the switch S2 is turned off, a speed command is obtained by multiplying the value of the error counter 10 by the position gain Kp, and speed loop processing is performed on this speed command to drive the spindle motor 4. (Step 1)
09). Then, it is determined whether or not the positional deviation, which is the value of the error counter 10, is "0" (step 110), and if it is not "0", the processing of the corresponding processing cycle is ended.

Since the flag Fp is "1" in the subsequent processing cycles, steps 100 to 102, steps 109 and 110 will be executed, and the above steps will be carried out in each cycle until the positional deviation becomes "0". Perform processing.

Then, when the positional deviation of the value of the error counter 10 becomes "0", steps 110 to 11 are performed.
1, output a fixed position stop completion signal to the NC device 8,
The completion flag Fe is set to "1" and the processing of the corresponding processing cycle is ended. As a result, the spindle motor 4 rotates by the amount of movement Ps set in step 107, and when the position deviation of the error counter 10 becomes "0", the rotation of the spindle motor 4 stops, and the spindle moves to the set stop position Pg. It will stop. From the next processing cycle, the completion flag Fe
is set to "1", so step 100
, step 101 are performed, and the processing of each cycle is completed. Then, when the next spindle drive command is input, each of the above flags is set to "0". Also, if the next spindle drive is a fixed position stop command, the flag Fo
only is set to "1".

[0021]

As described above, in the present invention, in a device in which the main shaft is driven by a main shaft motor via a gear or a timing belt, a one-rotation signal is provided to the main shaft, which outputs a signal once for one rotation of the main shaft. By attaching only the detection mechanism and a position/speed detector to the spindle motor, the spindle can be positioned at any set position within one rotation of the spindle, and only the one-rotation signal detection mechanism is attached to the spindle. Since it is only necessary to use only the main shaft, the configuration on the spindle side can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of processing executed by a processor of a motor control circuit in an embodiment of the present invention.

FIG. 2 is a block diagram showing a spindle drive system for implementing the same embodiment.

FIG. 3 is a detailed block diagram of a motor control circuit implementing the same embodiment.

[Explanation of symbols]

1 Main shaft 2 Transmission mechanism 3. One revolution signal detection mechanism 4 Main shaft motor 5　Position/speed detector 6 Power circuit 7 Motor control circuit 8 Numerical control device (NC device) 10 Error counter 19 Counter 20 Latch circuit

Claims (1)

[Claims] 1. In a spindle positioning method in a spindle drive method in which the spindle of a machine tool is driven by a spindle motor via a gear or a timing belt, a detection method is provided in which a one-rotation signal is output to the spindle once for one rotation of the spindle. Attach the speed/position detector to the above spindle motor,
A counter that counts the position feedback pulses output from the speed/position detector and a latch circuit that latches the value of the counter every time the one rotation signal is output are provided. The speed of the spindle motor was controlled to a predetermined speed, and when the set speed was reached and the one rotation signal was detected, the values of the counter and latch circuit were read, and the value of the latch circuit was subtracted from the read counter value. The value is subtracted from the amount of movement per one revolution of the spindle, and the set amount of movement from the one-rotation signal detection position is added to the error counter as the position deviation.Switching from speed control to position control, the value of the error counter is A spindle positioning method that stops the spindle at a set position by setting the value to “0”.