JP2681636B2 - Spindle synchronization adjustment method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a spindle synchronous adjustment method for rotating two spindles of a spindle drive device in synchronization with each servo motor. BACKGROUND OF THE INVENTION For example, a turning broaching device supports a workpiece such as an inter-engine crankshaft between two spindles facing each other at both ends, and a portion required by a cutting tool while rotating each spindle with a servomotor. Perform the cutting process. When the rotational phases of the left and right spindles are deviated during this processing, torsional stress is generated in the work, making precise processing difficult. Therefore, when driving the pair of spindles, highly accurate synchronous control is required between the servo motors of the respective spindles. [Prior Art] In the conventional synchronous control, resolvers are attached to the servomotors of the respective spindles and the phase difference between them is fed back to the servomotor on the tracking side as a correction signal. If such synchronous control is executed in an ideal state, the two servo motors will apply a rotational force to the pair of spindles in a synchronized state regardless of load fluctuations between the spindles. If the phase angle between the rotor and the stator is relatively deviated between the two resolvers due to mounting error or the like,
Synchronous control is not performed accurately. Therefore, when the two servomotors are localized and in a stationary state, the phase angle between the rotor and the stator of the two resolvers must be accurately aligned with the reference position in the initial state. However, when a workpiece is mounted in a clamped state between a pair of spindles, the two servomotors are mechanically linked by both spindles and the workpiece, and lose the freedom of rotation individually, so even in the stationary state, Compensation of the phase difference between the two resolvers becomes difficult. In addition, before the work is assembled, the pair of spindles are not connected again, so it is possible to mechanically adjust the phase difference on either servo motor side, but this adjustment causes either spindle to rotate. Therefore, the clamp means for the left and right spindles are out of phase with each other, which makes it difficult to assemble the work thereafter. Thus, in any case, adjustment of the phase difference between the two resolvers is practically difficult as long as mechanical means is used. OBJECT OF THE INVENTION Therefore, it is an object of the present invention to make it possible to easily adjust the phase difference between two resolvers. Therefore, according to the present invention, an intermediate resolver is connected between the resolver of the servo motor on the master side and the resolver of the servo motor on the slave side, and the stator and the rotor of the intermediate resolver are connected. By adjusting the phase between the two resolvers, the relative phase difference between the two resolvers is removed by electrical compensation. As a result, even if there is a mechanical phase difference between the master-side and slave-side resolvers in the servo motor localization state, the output of the slave-side resolver can be extracted as a signal that does not include the phase difference. Therefore, it can be directly used as a feedback signal for tracking control. The synchronization state can be determined by the output signal of the resolver on the slave side, that is, the signal level. The present invention makes it possible to easily confirm from the outside by comparing such a level with a reference value. [Structure of the Invention] First, FIG. 1 shows a spindle drive device 1 on which the present invention is based.
Is shown. This spindle drive device 1 is incorporated in, for example, a turning broaching device, and two spindles 2, 3 are arranged on the same axis.
Are provided facing each other. And these spindles 2, 3
Are rotatably supported by spindle heads 4 and 5, respectively, and are driven by servomotors 6 and 7 in a synchronous state via transmission means 8 and 9. On the other hand, the work 11 such as the crankshaft is
3 is supported in a fixed state by suitable clamping means 2a, 3b, and is rotationally driven by a pair of main shafts 2, 3. Then, for this rotating workpiece 11, the tool 10
By the linear feed movement, necessary cutting work is performed on the working part of the work 11. Next, FIG. 2 shows a spindle synchronous control device 12 according to the present invention. This spindle synchronization control device 12 has, inside the synchronization control unit 13,
A speed control circuit 14, a reference oscillation circuit 15, an output circuit 16, a comparison circuit 17 and a switching circuit 18 are provided. The speed control circuit 14, the numerical control device 19 on the input side,
On the output side, they are connected to the servo amplifiers 21 of the master side servo motors 6, respectively, and further branched and connected to the servo amplifiers 22 of the slave side servo motors 7 via the addition points 20. These servomotors 6 and 7 are mechanically connected to speed detectors 23 and 24 and resolvers 25 and 26, respectively. Also, the speed detector 23,
24 is connected to the feedback side inputs of the servo amplifiers 21 and 22, respectively. The reference oscillator circuit 15 is electrically connected to the output circuit 16 and the resolver 25 on the master side, and
This resolver 25 is electrically connected to a slave-side resolver 26 via an intermediate resolver 27. Further, this resolver 26 is connected to the above-mentioned addition point through the output circuit 16.
It is connected to 20 and is also connected to the comparison circuit 17. The comparison circuit 17 is connected to the display lamps 28 and 29 via the switching circuit 18. [Operation of the Invention] In order to perform the synchronous control with high precision, the mechanical operation between the resolvers 25 and 26 for the servomotors 6 and 7 is performed mechanically while the servomotors 6 and 7 are mechanically locked in the localization state. The phase difference is manually adjusted by rotating the intermediate resolver 27 so that the phase difference is electrically adjusted to zero. Now, as shown in FIG. 3, the rotors of the resolvers 25, 26, 27
It is assumed that 25a, 26a, and 27a are displaced from the reference positions of the stators 25b, 26b, and 27b by phase angles θ ₁ , θ ₂ , and φ, respectively. In this state, the reference signal Sin from the reference oscillation circuit 25
When (ωt) is applied to the first resolver 25, the output of the resolver 25 is affected by the phase angle θ ₁ between the two phases,
It is converted into two signals as shown in Fig. 3 and an intermediate resolver is used.
The signal of the sine and cosine shown in the following formulas (1) and (2) is applied to the 27 side, is converted by the influence of the phase angle φ, is converted, and is further applied to the resolver 26 on the slave side. Becomes Sin (ωt) · Cos (θ ₁ −φ−θ ₂ ) …… (1) Sin (ωt) · Sin (θ ₁ −φ−θ ₂ ) …… (2) Here, regarding the resolver 27, the rotor 27 a When the angle (θ ₁ −φ−θ ₂ ) = 0 is obtained as a result of the phase angle being adjusted by electrical compensation by manually rotating, the above formula (1) becomes Sin (ωt), and Equation (2) is
Always 0. In this way, the initial mechanical phase difference between the resolvers 25, 26 is the rotor 27 of the intermediate resolver 27.
By adjusting the mechanical phase angle φ between the a and the stator 27b, it is possible to perform compensation adjustment so that the phase difference is electrically zero. This adjustment state can be easily confirmed by observing the signal levels of equations (1) and (2). FIG. 4 shows the waveform at the time of this adjustment. Considering only the case where the angle (θ-φ-θ ₂ ) is greater than 0, the signals of the two expressions (1) and (2) change as shown in FIG. Here, the angle (θ ₁ −φ−θ ₂ ) = 0
If so, the signal level of the equation (1) is always 0, and the waveform of the equation (2) changes with the maximum amplitude. Then, the signals of these equations (1) and (2) pass only during the half-wave period T of the reference signal due to the synchronous switching function of the output circuit 16 or the rectification function,
It becomes a half-wave signal and is sent to the comparison circuit 17 together. Therefore, as shown in FIG. 4, the comparison circuit 17 uses the equation (1)
The signal level of the half-wave signal in (2) is compared with the reference threshold value, and when it is within the allowable range, the switching element inside the corresponding switching circuit 18 is driven and the corresponding display lamps 28, 29 are turned on. Turn on the light. Therefore, in the process of adjusting the resolver 27 in the middle, the operator can identify the state of electrical phase matching by checking the simultaneous lighting of the display lamps 28 and 29. Even if the half-wave signal of the equation (2) is near 0, it is unknown from the equation (2) alone whether the electrical phase difference is 0 degree or 180 degrees. However, on the other hand, if the half-wave signal of the equation (1) is on the negative side in the same period T, then it can be seen that the phase difference is +90 degrees or more at this time. In this way, by manually adjusting the rotation of the rotor 27a of the intermediate resolver 27 so that both display lamps 28 and 29 are lit before the servomotors 6 and 7 are started, The mechanical phase difference between the resolver 25 on the side and the resolver 26 on the slave side is electrically compensated so that the phase difference becomes zero. After such adjustment, the synchronization control unit 13 causes the numerical control device to
A speed command signal is generated on the basis of a command from 19, and the servo amplifiers 21 and 22 are driven by this to rotate the servo motors 6 and 7 at the same time so as to synchronize with each other. At this time, the servo motors 6 and 7
The rotational speed of is detected by the speed detectors 23 and 24, respectively, and is negatively fed back to the corresponding servo amplifiers 21 and 22 as a speed feedback signal so as to approach the target speed. As described above, the reference signal Sin (ωt) as the output of the reference oscillation circuit 15 is a trigonometric function signal and is electrically connected to the resolver 25 and the like when the servomotors 6 and 7 are stationary. The resolvers 27 and 26 are provided to generate a signal having a predetermined output. In this operating state, the resolvers 25 and 26 are individually driven by different servo motors 6 and 7, respectively, and are affected by load fluctuations.
The phase angle of 26 changes with time according to load fluctuations. The output signal of the resolver 26 at that time is
Using the angular velocities ω ₁ and ω ₂ of 25 and 26, it is given by the following equation. Sin (ωt) ・ Cos (θ ₁ + ω ₁ t−φ−θ ₂ −ω ₂ t) Sin (ωt) · Sin (θ ₁ + ω ₁ t−φ−θ ₂ −ω ₂ t) By the way, before starting And the angle (θ ₁ −φ−θ ₂ )
Since the adjustment of = 0 has been performed in advance, the above equation can be rewritten as follows. Sin (ωt) · Cos (ω ₁ t−ω ₂ t) (3) Sin (ωt) · Sin (ω ₁ t−ω ₂ t) (4) Then, these two equations (3) and The signal of Expression (4) in (4) is added to the addition point 20 as an output signal for synchronization control. As a result, the slave side servomotor 7 is influenced by the output signal in addition to the speed command signal and is accelerated until it synchronizes with the rotation of the master side servomotor 6. It should be noted that the output signal of the equation (4) is based on the electrical phase difference, that is, the synchronization, delay, and lead states,
It changes as shown in FIG. That is, in the synchronous state, that is, in the state of (ω ₁ t−ω ₂ t) = 0, the electrical phase signal is in the state of 0. Further, when the slave side servo motor 7 lags behind the master side servo motor 6, that is, when (ω ₁ t−ω ₂ )> 0, the electrical phase signal is in phase with the reference signal, And its amplitude is proportional to | Sin (ω ₁ t−ω ₂ t) |. Further, when the slave side servo motor 7 is ahead of the master side servo motor 6, that is, (ω ₁ t−ω ₂
t) <0, the phase difference signal is in anti-phase with the reference signal, and its amplitude is | Sin (ω ₁ t−ω ₂ t).
Is proportional to |. Therefore, by setting the reference signal so that it passes through the output circuit 16 for the electrical phase signal only for a predetermined period T, this output signal can be used as a correction signal for synchronization as it is. Note that, even during this rotation, the signals of the formulas (3) and (4) are sent to the comparison circuit 17, so that the display lamps 28 and 29 are lit in the same manner as during the adjustment to display the synchronization state. Thus, in the operating state, the reference signal Sin (ωt) is
A signal level necessary for comparing the signals of equations (3) and (4) with the comparison circuit 17 is given. In the above embodiment, the turning broaching machine is explained as an example, but this spindle synchronous adjustment method is
As long as the two main shafts 2 and 3 are driven by the respective servo motors 6 and 7, it is naturally applicable to other devices. [Effects of the Invention] In the present invention, the following unique effects are obtained. An intermediate resolver is electrically interposed between the resolver of the master side servo motor and the resolver of the slave side servo motor, and the intermediate resolver is checked by the indicator lamp to confirm the electrical phase shift state between the resolvers. By adjusting the rotor of (1), the adjustment for electrically compensating the mechanical phase difference can be performed. During operation, the output signal of the resolver on the slave side can be used as it is as a signal for electrically correcting the phase angle deviation, so that the synchronous control can be realized with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view of a spindle drive device, FIG. 2 is a block diagram of a spindle synchronous control device, FIG. 3 is an explanatory diagram of a signal conversion process of a resolver, and FIG. Is a waveform diagram during phase difference adjustment, and FIG. 5 is a waveform diagram during operation. 1 ... Spindle drive device, 2, 3 ... Spindle, 6, 7 ... Servo motor, 12 ... Spindle synchronous control device, 13 ... Synchronous control unit, 14 ... Speed control circuit, 15 ... Reference oscillation circuit , 16 ……
Output circuit, 17 …… Comparison circuit, 18 …… Switching circuit,
20 …… Addition point, 21,22 …… Servo amplifier, 23,24
...... Speed detector, 25, 26, 27 ...... Resolver, 28, 29 ......
Indicator lamp.

Claims (1)

(57) [Claims] Based on one speed command signal from the speed control circuit of the synchronous control unit, the master side servo amplifier drives the master side servo motor to rotate the master side main shaft and the slave side servo amplifier drives the slave. In a main spindle drive device that drives two slave spindles in a synchronized state by driving the master servo motor, the resolver (25) connected to the master servo motor and the slave servo motor An intermediate resolver (27) is connected between the resolver (26) connected to and the output of the master resolver (25) is applied to the intermediate resolver (27).
A comparison circuit that electrically connects the output of the intermediate resolver (27) to the slave resolver (26) and compares the sine and cosine outputs from the slave resolver (26) with reference values. (17) is provided, and the indicator lamps (28) and (29) that are turned on when both outputs are within the allowable range with respect to the reference value by this comparison circuit (17) are provided, and both servo motors are locked in the localization state. Then, by rotating the rotor of the intermediate resolver (26) and adjusting the relative positional relationship between the stator and the rotor until both indicator lamps (28) (29) are both turned on, A spindle-synchronized adjustment method characterized in that adjustment is performed to electrically compensate a mechanical phase difference between a resolver (25) on a master side and a resolver (26) on a slave side.