TW201617534A - Method of determining parallelism between two sliding rails of ball screw feeding system with embedded sensor module - Google Patents

Abstract

The present invention provides a method of determining parallelism between two sliding rails of ball screw feeding system with embedded sensor module, which includes the following steps: (A) preparing: configuring a plurality of vibration sensors at proper positions of a ball screw feeding system; (B) driving and capturing signals: driving the carrier in a reciprocal motion of a predetermined stroke and capturing the signals sensed by the vibration sensors; (C) low-pass filtering process: performing low-pass filtering process on the sensed signals; (D) common correlation analysis; (E) empirical mode decomposition: performing the empirical mode decomposition for the values obtained by the analysis in step (D) being larger than a predetermined critical value to obtain a plurality of sets of decomposition signal matrixes; and (F) parallelism determination: each of the plurality of sets of decomposition signal matrixes has one feature waveform signal, and the ratio of the amplitude in the initial section to the amplitude in the rear section for each of the feature waveform signals is employed to determine the parallelism between two sliding rails.

Description

Method for judging parallelism between two rails of a ball screw feeding system by using an in-line sensing module

The invention relates to a feeding system, in particular to a method for determining the parallelism between two rails of a ball screw feeding system by using an in-line sensing module.

In the feed system of the ball screw, the screw is mainly composed of a screw, a loading platform, a nut, a second sliding rail and a driving motor, wherein the loading platform is disposed on the nut, and the nut is screwed to the a screw, and the nut is internally provided with a circulation passage for allowing a plurality of balls to be accommodated between the circulation passage and the nut and the screw, and the stage is slidably pivoted to the two slide rails. The foregoing construction is the basic structure of a conventional ball screw, which is well known to those skilled in the art and is not shown in the drawings.

However, in the aforementioned feed system, the weight of the carrier and the two slides responsible for guiding the linear motion play a key role in the quality of the feed system. This is because the parallelism between the two slide rails has a direct influence on the movement condition of the stage, thereby affecting the feeding condition of the tool set on the stage, which affects the processing precision and the processed product. Reliability. Long-term use of non-parallel rails, the wear caused by the platform or the two rails, in addition to making the feed condition worse, will greatly reduce the service life of the feed system.

At present, the adjustment of the parallelism between the two slide rails is mainly carried out during the assembly of the machine, or fine-tuned at the factory to meet the standards required by the customer. The system with high precision level can correct the parallelism between the two slide rails through precision measuring equipment such as laser and dial gauge and corresponding standard operating procedures. The system with lower precision level requirements is limited by the level of funding and adjustment equipment. The parallelism of the adjustment is often inaccurate, which will cause the above-mentioned precision and life problems caused by non-parallelism. .

In addition, although the machine has been adjusted before leaving the factory, but after using it for a period of time after leaving the factory, it is still possible to change the parallelism due to external factors. The general practice is to monitor and adjust the external measuring equipment. However, there must be a downtime during inspections and adjustments, and production pauses and maintenance costs during downtime may increase operating costs.

The main object of the present invention is to provide a method for determining the parallelism between two slide rails of a ball screw feeding system by using an in-line sensing module, which is to install a plurality of sensors in a feed system and cooperate with corresponding analysis techniques. Parallelism can be measured during the operation of the feed system and no external measuring equipment is required.

A second object of the present invention is to provide a method for discriminating the parallelism between two rails of a ball screw feeding system by using an in-line sensing module, which can achieve measurement parallelism without increasing the production cost of the machine. Effect.

Another object of the present invention is to provide a method for discriminating the parallelism between two rails of a ball screw feeding system by using an in-line sensing module, which can measure the parallelism during the operation of the feeding system, Need to stop for measurement.

In order to achieve the foregoing object, the present invention provides a method for determining the parallelism between two rails of a ball screw feeding system by using an in-line sensing module, comprising the following steps: A) preparing: in a ball screw feeding system A vibration sensor is disposed on the nut and the bearing seat, and two vibration sensors are disposed on the stage of the ball screw feeding system, respectively, adjacent to the two sliding rails of the ball screw feeding system; B) driving and Swapping signal: driving the stage to perform a predetermined stroke reciprocating motion under different feeding conditions for a predetermined length of time; during the reciprocating motion of the stage, the vibration sensations are respectively taken at an appropriate sampling frequency The signal sensed by the detector; C) low-pass filtering processing: the signals sensed by the vibration sensors are respectively subjected to low-pass filtering processing to obtain waveform signals corresponding to the vibration sensors, each of the waveforms There must be a plurality of adjacent pulses in the signal. The two adjacent pulses correspond to the turning point of the reciprocating motion of the stage, and the signal between two adjacent pulses is the feeling of one-way motion. To the signal, and the signal is defined as a one-way section; D) common correlation analysis: each of the way sections of the common signal for correlation analysis (correlation analysis), analysis if the resulting value is greater than a predetermined threshold value, it is determined that the current sub- The single-pass segment signal is sufficient to perform step E). If the value of the currently analyzed one-way segment signal is not greater than the predetermined threshold, then the analysis is not performed in step E); E) empirical mode decomposition: step D) the single-pass segment signal whose value is greater than the predetermined threshold value is subjected to Empirical Mode Decomposition, and the complex signal matrix of the complex array is obtained; and F) the parallelism is determined: the decomposition signal of the complex array The matrix has a characteristic waveform signal, and each of the characteristic waveform signals is mainly divided into an initial segment and a rear segment. In the initial segment, the amplitude of each of the characteristic waveform signals is defined as an initial amplitude, and the subsequent segment is defined. The amplitude of each of the characteristic waveform signals is defined as the amplitude of the rear section, and the parallelism between the two rails is determined according to the ratio of the initial amplitude to the amplitude of the rear section.

By installing the vibration sensors on the feed system, the parallelism can be measured during the operation of the feed system, and no external measuring equipment is needed, and the measurement can be performed without stopping the machine. . In addition, since only the vibration sensor is installed, the production cost of the machine is hardly increased.

10‧‧‧Rolling screw feed system

11‧‧‧ Nuts

12‧‧‧ screw

13‧‧‧ bearing housing

15‧‧‧ stage

17‧‧‧Slide rails

19‧‧‧Vibration sensor

FS‧‧‧Characteristic Waveform Signal

After the RS‧‧‧ section

SS‧‧‧ initial section

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart of a preferred embodiment of the present invention.

Figure 2 is a schematic view of the position of a preferred embodiment of the present invention showing the mounting position of the vibration sensor.

Fig. 3 is a schematic view showing the position of the second sensor turned to 180 degrees, showing the mounting position of the vibration sensor.

Fig. 4A is a schematic diagram of a signal according to a preferred embodiment of the present invention, showing a signal pattern having a feed condition of 20 meters/minute.

Figure 4B is a schematic diagram of a signal of a preferred embodiment of the present invention showing a signal pattern having a feed condition of 40 meters per minute.

Figure 4C is a schematic diagram of a signal of a preferred embodiment of the present invention showing a signal pattern having a feed condition of 60 meters per minute.

Figure 5 is a schematic diagram of a signal according to a preferred embodiment of the present invention, showing the low pass filtering process Signal graphic.

FIG. 6 is a schematic diagram of a signal according to a preferred embodiment of the present invention, showing a characteristic waveform signal of the decomposed signal matrix C9.

In order to explain in detail the technical features of the present invention, the following preferred implementations are presented. For example, as shown in FIG. 1 to FIG. 6 , a preferred embodiment of the present invention provides an in-line sensing module for discriminating a two-slide of a ball screw feeding system. The method of parallelism between rails mainly has the following steps: A) preparation: as shown in Figs. 2 and 3, a vibration is set on a nut 11 of a ball screw feeding system 10 and a bearing seat 13 of a screw 12. The sensor 19 is provided with two vibration sensors 19 on the stage 15 of the ball screw feed system 10, respectively, adjacent to the two slide rails 17 of the ball screw feed system 10. In this embodiment, each of the vibration sensors 19 is exemplified by an acceleration sensor.

B) Drive and capture the signal: drive the stage 15 with different feed conditions The reciprocating motion of a predetermined stroke is continued for a predetermined length of time; during the reciprocating motion of the stage 15, the signals sensed by the vibration sensors 19 are respectively captured at appropriate sampling frequencies. In this embodiment, the feed condition is related to the feed speed, including acceleration, constant speed, and deceleration. In addition, the stroke of the reciprocating motion (the distance traveled in a single direction) is not less than one of the slide rails 17 One-half of the length. The different feed conditions referred to above are different feed rates, such as 20 meters/minute, 40 meters/minute or 60 meters/minute. In addition, the aforementioned sampling frequency must be not less than 5 kHz, and in the present embodiment, 5 kHz is taken as an example. Further, the above-described reciprocating stroke is exemplified by 890 mm, and the predetermined length of time is mainly based on the time during which the stage is reciprocated three times or more, and in general operation, four reciprocating motions are performed. The number of signals taken is sufficient to make the correct parallelism. In this embodiment, 80,000 pens can be achieved. However, the longer-stroke slides will capture more in 4 reciprocating motions. The number of signals. 4A, 4B, and 4C show that the stage 15 corresponds to the left rail in the two rails 17 The vibration sensor 19 picks up signals according to different feed rates (20 meters/minute, 40 meters/minute or 60 meters/minute) under the aforementioned conditions.

C) Low-pass filter processing: the signal points sensed by the vibration sensors 19 The low-pass filtering process is performed to obtain the waveform signals corresponding to the vibration sensors 19, and each of the waveform signals necessarily has a plurality of adjacent pulses, and the two adjacent pulses correspond to the stage. 15 The turning point of the reciprocating motion, and the signal between the two adjacent pulses is the signal sensed by the one-way motion, and is defined as the one-way segment signal. In this embodiment, the cutoff frequency of the low pass filtering is not less than 50 Hz, and 100 Hz is taken as an example. Figure 5 shows the waveform signal after low-pass filtering processing according to the signal of Figure 4B.

D) Common correlation analysis: co-correlation analysis of each one-way segment signal Correlation analysis, if the value obtained by the analysis is greater than a predetermined threshold, it is determined that the one-way segment signal currently analyzed is sufficient to perform step E), and the value of the currently analyzed one-way segment signal is not greater than the predetermined threshold value, Then no analysis is performed in step E). In this embodiment, the predetermined threshold value must be not less than 0.8, and 0.8 is taken as an example.

E) empirical mode decomposition: the value of the analysis in step D) is greater than the predetermined The one-way segment signal of the critical value is subjected to Empirical Mode Decomposition, and a complex array of decomposed signal matrices (for example, C1, C2, ..., C16) is obtained, wherein the empirical mode decomposition is a conventional technique and The technical focus of this case is not to be described.

F) determining parallelism: the complex signal matrix of the complex array has a characteristic wave The shape signal FS, each of the characteristic waveform signals FS is mainly divided into an initial segment SS and a rear segment RS. In the initial segment SS, the amplitude of each of the characteristic waveform signals FS is defined as an initial amplitude, in the rear region. In the segment RS, the amplitude of each of the characteristic waveform signals FS is defined as the amplitude of the rear segment RS, and the parallelism between the two slide rails 17 is determined according to the ratio of the initial amplitude to the amplitude of the rear segment RS. In this embodiment, each of the characteristic waveform signals FS has a larger amplitude in the initial segment SS, and the amplitude of the subsequent segment RS is smaller. In the present embodiment, the corresponding signal waveform signal FS is used as an example of the decomposed signal matrix C9, and the graph is as shown in FIG. 6. Wherein, the amplitude of the initial section SS is large as a numerator, and the amplitude of the back section RS is small as a denominator. Therefore, the greater the ratio, the better the parallelism of the two slide rails 17 is. This ratio can be judged when discriminating the parallelism.

As can be seen from the above steps, the present invention installs plurals in the feed system 10. The vibration sensor 19 collects data for analysis, and the parallelism can be measured during the operation of the feed system 10, and no external measuring equipment is required, and the measurement can be performed without stopping. Further, since only the vibration sensor 19 is mounted, the machine production cost is hardly increased.

Claims (7)

A method for judging the parallelism between two rails of a ball screw feeding system by using an in-line sensing module comprises the following steps: A) preparing: setting a vibration on a nut and a bearing seat of a ball screw feeding system a sensor, and two vibration sensors are disposed on the stage of the ball screw feeding system, respectively, adjacent to the two slide rails of the ball screw feeding system; B) driving and capturing signals: with different feeds a condition of driving the stage to perform a reciprocating motion of a predetermined stroke for a predetermined length of time; during the reciprocating motion of the stage, respectively, the signals sensed by the vibration sensors are captured at an appropriate sampling frequency; a low-pass filtering process: the signals sensed by the vibration sensors are respectively subjected to low-pass filtering processing to obtain waveform signals corresponding to the vibration sensors, and each of the waveform signals necessarily has a plurality of two-phase phases Neighboring pulses, the two adjacent pulses correspond to the turning point of the reciprocating motion of the stage, and the signal between the two adjacent pulses is the signal sensed by the one-way motion, and is defined as a one-way section. News ; D) Common correlation analysis: Correlation analysis is performed on each of the one-way segment signals, and if the value obtained by the analysis is greater than a predetermined threshold, it is determined that the one-way segment signal currently analyzed is sufficient for step E), If the value obtained by the currently analyzed one-way segment signal is not greater than the predetermined threshold value, then no analysis is performed in step E); E) empirical mode decomposition: the value obtained by analyzing in step D) is greater than the predetermined threshold value. The one-way segment signal performs an Empirical Mode Decomposition to obtain a complex array of decomposed signal matrices; and F) determines the parallelism: the decomposed signal matrices of the complex array respectively have a characteristic waveform signal. Each of the characteristic waveform signals is mainly divided into an initial segment and a rear segment. In the initial segment, an amplitude of each of the characteristic waveform signals is defined as an initial amplitude, and in the subsequent segment, each of the characteristic waveform signals is The amplitude is defined as the amplitude of the rear section, and the parallelism between the two rails is determined according to the ratio of the initial amplitude to the amplitude of the rear section. The method for determining the parallelism between the two rails of the ball screw feeding system by using the in-line sensing module according to Item 1 of the patent application scope, wherein: the feeding condition in the step B) is related to the feed speed, including Three parts of acceleration, constant speed and deceleration; the distance traveled in a single direction in the reciprocating motion is not less than one-half of the length of one of the slide rails. The method for determining the parallelism between the two rails of the ball screw feeding system by using the in-line sensing module according to the first aspect of the patent application, wherein the sampling frequency in the step B) is not less than 5 kHz. The method for determining the parallelism between the two rails of the ball screw feeding system by using the in-line sensing module according to the first aspect of the patent application, wherein the cutoff frequency of the low-pass filtering in step C) is not less than 50 Hz. The method for determining the parallelism between the two rails of the ball screw feeding system by using the in-line sensing module according to the first application of the patent scope, wherein the predetermined threshold is not less than 0.8. The method for determining the parallelism between two rails of a ball screw feeding system by using an in-line sensing module according to claim 1 of the patent application scope, wherein: in step F), each of the characteristic waveform signals is in the initial section The amplitude is large and the amplitude in the latter section is small. The method for determining the parallelism between the two rails of the ball screw feeding system by using the in-line sensing module according to the first aspect of the patent application, wherein each of the vibration sensors is an acceleration sensor.