JP2844066B2 - Spindle orientation control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a spindle orientation control device for controlling a spindle motor to stop at a fixed position. (Prior Art) In a numerically controlled (NC) machine tool, there is a demand for stopping a spindle at an arbitrary rotational position with high accuracy according to a purpose. For example, in order to perform tapping processing at a predetermined rotation angle position on a work using a lathe, it is necessary to stop the spindle at a predetermined rotation position (spindle orientation). FIG. 5 shows a case where a spindle A is connected to a servo motor M acting as a spindle motor via a gear d and spindle orientation control is performed by an NC device a.
FIG. 1 is a block diagram showing a known spindle orientation control device as disclosed in Japanese Patent Application Publication No. 56-97106. In the figure, SW is a switch for transmitting the command of the NC device a by switching the speed control circuit b to the position control circuit c, TG is a speed generator for detecting the speed AV of the servomotor M, and S is the main shaft. This is a magnetic sensor that detects a rotational position. Next, the operation of the orientation control device will be described with reference to the characteristic diagram of FIG. Spindle shall orientation command to the speed control circuit and the position control circuit from the NC device (ORCM) is output is controlled at a constant speed, when reaching the time t _0, the speed command VCMD is decreased at a constant slope Characteristics. If at time t ₁ the rotational speed of the servo motor to a predetermined speed is reduced, the process proceeds to the constant speed rotation from time t ₁ to time t _2, the where the switch SW contacts b from the contact a
The connection with the NC device is changed from the speed control circuit to the position control circuit. During than this until time t _3, the rotational position of the main shaft is controlled by a signal of the magnetic sensor S, it is stopped at the target position. (Problems to be Solved by the Invention) In such a conventional spindle orientation control device, the speed AV of the servomotor M is input to a position control circuit, which is integrated by an integrating circuit (not shown) to obtain a position deviation of the spindle. Signal was formed. It should be noted that the technical means for inputting the speed AV of the servo motor M to a position control circuit and integrating it in an integration circuit to form a position deviation signal of the main shaft is known, but, for example, for example, In FIG. 6 of the above-mentioned Japanese Patent Application Laid-Open No. 56-97106, page 15, upper right column, line 15 to lower right column, second line, "FIG. ] Is described in detail. For this reason, it is necessary to adjust the volume of the integration circuit,
There has been a problem that the circuit is complicated and the operation for performing arithmetic control becomes complicated. That is, as described above, in the conventional apparatus, the position deviation signal is integrated and created. In this case, it is necessary to adjust the integration time constant according to the gear ratio between the main shaft and the motor, but a volume is required for the adjustment. The necessity of the switching circuit for switching the circuit in accordance with the sequence of the integrating circuit and the time constant adjusting circuit mean that the whole circuit becomes complicated. Further, since the position gain was kept constant in the course of the orientation control, there was a problem that overshoot occurred at the fixed position stop and the stability of the control system was impaired. Accordingly, the present invention provides a spindle orientation control device for solving such a problem of the conventional technology. (Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. That is, the spindle from which the stop position near (LS) signal and the stop position determination (MS) signal of the spindle are taken out is connected to the spindle motor via the connection means, and a pulse signal corresponding to the rotation speed of the spindle motor is output. A spindle orientation control device that controls the spindle speed using the pulse signal from the speed detector as a feedback signal, and controls the stop of the spindle at a fixed position using the LS signal, the MS signal, and the pulse signal. Setting means for setting the position gain of the spindle, calculating means for increasing or decreasing the position gain in proportion to the gear ratio of the coupling means to determine an orientation speed, and an orientation command or output for controlling stop of the spindle at a fixed position. When the spindle reaches the orientation speed determined by the calculating means after the Latch means for latching the pulse number at this time of the pulse signal output from the speed detector upon detection of the rising edge of the signal, and using the latched pulse number as an intended speed command value, and detecting the speed command value as a feedback speed detection value. Speed command means for gradually decreasing the spindle speed by gradually reducing the feedback pulse obtained from the device, and when the gradually reduced spindle rotation speed reaches a speed normalized to the maximum value of the MS signal, the speed is increased. Speed control means for maintaining, when the LS signal is detected during the spindle control by the speed control means, spindle fixed position stop control means for controlling the spindle to stop at a fixed position using the MS signal; and When the main shaft is stopped at a fixed position by the fixed position stop control means, switching to a position gain higher than the position gain set by the setting means to perform the fixed position stop control of the main shaft. And it is characterized in that formed by comprising: a stage, a. (Operation) By adopting the above configuration, the present invention performs orientation control of the spindle using the speed pulse of the motor. Therefore, automatic home position control is possible only by setting the position gain, and the circuit configuration is simplified. In addition, the volume adjustment operation can be reduced. Further, by increasing the position gain at the end of the orientation, the stopping rigidity is increased, and the occurrence of overshoot can be prevented. (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a spindle orientation control device. In the figure, 1 is an arithmetic circuit including a microcomputer and the like, 2 is a spindle motor,
3 is a speed detector, 4 is a main shaft, 5 is a gear or a belt connecting the spindle motor and the main shaft, 6 is a mounting portion for fixing a magnet 8 of a magnetic sensor 7, 9 is a magnetic sensor head, 10
Is an amplifier, 11 is a position gain setting device, 12 is an orientation completion signal generation circuit, 13 and 14 are comparators, 15 and 16 are amplifiers, and 17 and 18 are changeover switches. The signal detected by the speed detector 3 is input to the arithmetic circuit 1 and the comparator 13 as a speed feedback signal, and the current supplied to the spindle motor is fed back to the comparator 14 to form a minor loop. Further, a stop position vicinity signal LS and a stop position determination signal MS are input to the arithmetic circuit 1 from the magnetic sensor 7. As shown in FIG. 2, the magnetic sensor 7 has a length L (mm).
The magnetic sensor head 9 is disposed at a position H (mm) away from the center of the spindle mounting portion 6. Next, the operation of the apparatus of the present invention will be described with reference to FIG. 3. The specifications of the apparatus are defined as follows. (A) Gear ratio Each gear ratio between the spindle (Ag) and the spindle motor (Mg)
Ag: Mg = 1: n. (B) The detection pulse of the speed detector 3 is np (pulse / 1 rotation)
And (C) The position gain is set as P _G sec ⁻¹ by the position gain setting means. Here, P _G is the motor rotation amount when driving the motor so that the position deviation becomes zero when the motor is rotating at a constant speed at a speed V (rad / sec), as θ (rad). Then, P _G = V / θ is defined, and is generally expressed in a form in which the command speed is divided by the position deviation. In FIG. 3, the speed command VCMD when controlled by the orientation command (ORCM) is given by the arithmetic means as follows. In the area (1), it is determined by the position gain and the gear ratio
_{VCMD = 60 × P G × n} (rpm) is commanded. (The present invention,
The orientation of the magnetic sensor system as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 56-97106 is basically based on stopping the spindle after making one rotation after switching to the fixed position stop mode. Therefore, when there is a position deviation of one rotation,
The spindle speed command VCMD at that time sets the position gain.
Assuming PG, from the definition of position gain, VCMD-PG x 1 rev x 60 sec [rpm] Just in case, setting the definition of position gain,
"A constant when multiplying the position deviation by a constant to obtain a speed command (rad / sec) is called a position gain." Assuming that the gear ratio between the main shaft and the motor is 1: n, the motor speed command VCMD at that time is as follows: VCMD = PG × 1rev × 60 sec × n [rpm]. ) (1) in the region of the → (2), when the LS signal is generated at time t _0, is latched by the latch means the value of the speed pulse counter provided in the rise in the operation circuit LS signal. In the area (2), the speed pulse is used as a position pulse, and the speed command means reduces the speed command VCMD by the amount of the feedback pulse. (3) region of the level A of the speed command VCMD at time t ₁ is, A = {(L / 2 ) / (2 × H × π)} × 60 × P G = (L × 15 × P G) / a constant speed control region after reaching the (H × π), it is continued by the speed control means to the rising time t ₂ of the LS signal. (As shown in FIG. 3, the rotational speed of the spindle decreases in accordance with the speed command, and the decrease is so rapid that the spindle cannot reach the control region of the MS signal which is the original spindle positioning signal. In order to solve the problem of stopping, when the spindle reaches a predetermined speed A, the speed is fixed and a constant speed operation is performed to rotate the spindle to the MS signal control region.) (4) The region indicated by parentheses) is a region controlled by the speed command (X-Y) based on the MS signal. The peak value X of the MS signal is normalized to the level A, and the time t at which the MS signal crosses zero is obtained. _{In step 3} , the spindle is stopped by the spindle fixed position stop control means. Note that the MS signal is a signal for positioning the main shaft. When the center is at zero voltage and the position is shifted therefrom, the signal increases or decreases according to the shifted position. The dominant region of the MS signal is a limited narrow range, and beyond that range, the MS signal is not attenuated. The LS signal is a signal for indicating that this MS signal is in a range effective as a positioning signal. In the orientation control regions (1) to (4), the changeover switch 17 is on and the switch 18 is off, and the position gain setting device set to a low value in the control system.
PG ₁ is connected. In the area (5) where the orientation control has been completed, the signal from the orientation completion signal generating circuit 12 is used to switch the changeover switch 17 serving as the switching means.
Off, 18 is turned on, the position gain setter PG _2, which is set to a high value is connected to the control system. The speed command VCMD in this case, VCMD = (position deviation) × PG _2, and the elevated stops rigidity, to prevent the occurrence of overshoot. FIG. 4 is a flowchart showing a processing procedure of the present invention. Next, this flowchart will be described. First, orientation command OR in Step P ₁
CM checks whether the output, if the determination is NO, SQ ₁ ~SQ ₄ of the sequence state signal in step P ₂
To 0, also the position gain G _p, is set to the value G _p1 during orientation. If the determination is YES, determine whether a sequence SQ ₁ = 1 at step P _3. If it is determined NO at this time, the speed command in step P ₄
Set VCMD to VCMD ₂ . Here, VCMD ₂ is a speed command when the orientation speed is not limited. Next, performs condition judgment of TSA ≦ VCMD ₂ in step P _5, If this condition is satisfied, the sequence SQ ₁ in Step P ₆
= 1 [state in FIG. 3 (1)]. In Step P _3, when SQ ₁ = 1 is confirmed, and then checks the sequence SQ ₂ = 1 in step P _7. Judgment when the NO to determine whether the rise of the LS signal is detected in step S _8, the determination is if YES, a step P
_{In step 9} , SQ ₂ = 1 is set [state in FIG. 3 (2)]. In step P _7, if SQ ₂ = 1, then performs condition decision SQ ₃ = 1 in step P _10. The judgment at this time is
If NO, the level A then at step P ₁₁ A = VCMD ₁
Set as -ΔVCMD. Here, VCMD ₁ is the speed command when the orientation speed is not limited, and ΔVCMD is Δ
And VCMD = (Pd / pc) × n × G p × 60. Here, Pd is the number of speed feedback pulses after detecting the rise of the LS signal, and PC is the number of speed pulses when the motor is rotated n times. Then, by comparing the level A and VCMD ₂ in step P _12, A <
Setting the speed command VCMD in VCMD ₂ in step P ₁₃ does not satisfy the conditions of VCMD _2. In step P _12, Step P if A <VCMD _{2
At 14} , the speed command VCMD is set to level A. Subsequently comparing the speed command VCMD and VCMD _s in step P _15. Where VC
MD _s is a slow-down speed for switching the speed command to the MS signal, and _{VCMD s = {(1/2) /} (2πH)} × n × G p × 60 (rpm). If satisfied VCMD ≦ VCMD _s condition, the speed command VCMD set to slow down the speed VCMD _s in step P _16, FIG. 3 [Set to SQ ₃ = 1 in step P ₁₇ (3) Condition ]. In step P _10, the SQ ₃ = 1 is confirmed, then checks the SQ ₄ = 1 in step P _18. Determination LS signal in step P ₁₉ If NO, it is checked whether 1 (within the main shaft position is LS signal). If the determination at this time NO, the speed command VCMD set to slow down the speed VCMD _s in step P _20, sets the sequence SQ ₄ = 0 in step P _21. When in step P ₁₈ SQ ₄ = 1 is confirmed, and when the LS signal = 1 is confirmed in step P _19, the speed command VCMD in step P ₂₂ is set to a predetermined coefficient K times the MS signal, step set the sequence SQ ₄ = 1 in P ₂₃ [third
(State of FIG. 4)]. Next, check-in position of the spindle in the step P _24, If this condition is satisfied,
The position gain G _p is set to G _p2 in step P _25. Here, G _p2 is a gain when the orientation is stopped. As described above, one embodiment of the present invention has been described. However, since various different embodiments can be easily configured without departing from the spirit of the present invention, the present invention is not limited to the specifics described in the claims. The present invention is not limited to the embodiment. (Effects of the Invention) As described above, according to the present invention, the fixed position stop control of the spindle is performed using the motor speed detection pulse and the signal of the sensor for detecting the rotational position of the spindle. This eliminates the need for a circuit for integrating the speed feedback voltage, and the orientation control can be performed automatically. Furthermore, since the means for setting the position gain high by the orientation completion signal is provided, it is possible to increase the stopping rigidity and prevent the occurrence of overshoot.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a schematic configuration of the present invention, FIG. 2 is a layout diagram of a magnetic sensor, FIG. 3 is a characteristic diagram, FIG. 4 is a flowchart, and FIG. FIG. 6 is a characteristic diagram. DESCRIPTION OF SYMBOLS 1 ... Operation circuit, 2 ... Spindle motor, 3 ... Speed detector, 4 ... Spindle, 7 ... Magnetic sensor, 11 ... Position gain setting device, 12 ... Orientation completion signal generation circuit, 1
7,18 ... Changeover switch.

   ────────────────────────────────────────────────── ─── Continuation of front page       (56) References JP-A-56-97106 (JP, A)                 JP-A-56-53591 (JP, A)                 JP-A-62-229309 (JP, A)                 62-175302 (JP, U)

Claims (1)

(57) [Claims] Spindle stop position near (LS) signal and stop position determination (M
S) A spindle from which a signal is taken out is connected to a spindle motor via a connecting means, and the spindle signal is output as a feedback signal using the pulse signal from a speed detector which outputs a pulse signal corresponding to the rotation speed of the spindle motor. A spindle orientation control device that controls the stop of the spindle at a fixed position by using the LS signal, the MS signal, and the pulse signal, and setting means for setting the position gain of the spindle. A calculating means for increasing or decreasing the gear ratio in proportion to the gear ratio at the connecting means to determine an orientation speed; and an orientation command for stopping and controlling the main shaft at a fixed position is output, so that the main shaft reaches the orientation speed determined by the calculating means. Is output from the speed detector upon detection of the rise of the LS signal. Latch means for latching the number of pulses of the pulse signal at this time; and using the latched number of pulses as an initial speed command value, and gradually reducing the speed command value by a feedback pulse obtained from a feedback speed detector, thereby obtaining a spindle speed. Speed command means for gradually decreasing the speed, speed control means for maintaining the speed when the gradually reduced spindle speed reaches a speed normalized to the maximum value of the MS signal, and spindle control by the speed control means. During the above-mentioned LS
When a signal is detected, a spindle fixed position stop control means for controlling the spindle to stop at a fixed position using the MS signal, and when the spindle is stopped at a fixed position by the spindle fixed position stop control means, the setting is performed by the setting means. Switching means for switching to a position gain higher than the set position gain and performing stop control of the spindle at a fixed position.