Guide, Sensor Assembly, and Method

Abstract

According to the disclosure, a sensor assembly, in particular for a guide, is provided, which has a sensor and an analysis device. The analysis device determines a movement profile of the guide component based on a vibration signal detected by the sensor, wherein a part of the movement profile is used for the fatigue detection. Alternatively or additionally, it can be provided that the vibration signal detected by the sensor is filtered or digitally filtered and the or a movement profile of the guide component is determined based on the filtered or digitally filtered signal.

Claims

1. A guide comprising: a guide part; and a guide component configured to be guided and movable via the guide part, wherein a sensor is configured to detect a vibration signal of the guide component, wherein an analysis device is configured to analyze the vibration signal detected by the sensor, and wherein the analysis device is configured to at least one of (i) determine a movement profile of the guide component based on the vibration signal detected by the sensor and perform fatigue detection using the vibration signal of a part of the movement profile, and (ii) digitally filter the vibration signal detected by the sensor and determine the movement profile of the guide component based on the digitally filtered vibration signal.

2. The guide according to claim 1, wherein the analysis device is configured to determine a frequency band of the vibration signal and perform fatigue detection using the frequency band.

3. The guide according to claim 1, wherein the analysis device is configured to digitally filter the vibration signal detected by the sensor via at least one of a low-pass filter and a discrete wavelet transformation.

4. The guide according to claim 1, wherein the analysis device is configured to determine at least one part of the movement profile of the guide component, the at least one part of the movement profile including at least one of a standstill profile, a starting profile, an acceleration profile, a profile of constant velocity, and a braking profile.

5. The guide according to claim 4, wherein the analysis device is configured to at least one of: perform the fatigue detection in the profile of constant velocity; and determine a velocity of the guide component based on the vibration signal.

6. The guide according to claim 5, wherein the analysis device is configured to determine the velocity based on at least one of the starting profile and the acceleration profile.

7. The guide according to claim 1, wherein the analysis device is configured to determine at least one characteristic in one of the determined frequency band and the vibration signal.

8. The guide according to claim 7, wherein at least one of: the determined at least one characteristic includes at least one of a mean value, a mean absolute deviation (MAD), and a root mean square; the analysis device is configured to scale the determined at least one characteristic using a determined velocity; the analysis device is configured to, in the case that the at least one characteristic includes at least two characteristics, combine the at least two characteristics; and the analysis device is configured to output at least one of a warning and an alarm in response to an increase of the at least one characteristic.

9. The guide according to claim 1, wherein one of: the guide component is a guide carriage and the guide part is a guide rail, a housing, which has at least one of the sensor and the analysis device, being fixed on the guide carriage, the housing at least one of (i) being arranged on a side of the guide carriage facing in the longitudinal direction, (ii) enclosing the guide rail, (iii) partially encompassing the guide rail, and (iv) completely encompassing the guide rail; and the guide component is a threaded nut and the guide part is a guide spindle, the housing, which has at least one of the sensor and the analysis device, being fixed on the threaded nut, the housing at least one of (i) being arranged axially on the threaded nut, (ii) enclosing the guide spindle, (iii) partially encompassing the guide spindle, and (iv) completely encompassing the guide spindle.

10. The guide according to claim 7, wherein: the analysis device is configured to determine a slope of the at least one characteristic in comparison to at least one preceding value for the at least one characteristic; and at least one of: in response to the slope of the at least one characteristic being less than or equal to zero, the analysis device is configured to conclude that no fatigue is present; in response to the slope of the at least one characteristic being approximately zero, the analysis device is configured to conclude the guide is in a stable phase; and in response to the slope of the at least one characteristic being greater than zero, the analysis device is configured to conclude that fatigue is present in the guide.

11. The guide according to claim 7, wherein at least one of: the analysis device is configured to output a first warning in response to the at least one characteristic exceeding an upper limit; the analysis device is configured to output a second warning in response to a value of the at least one characteristic exceeding a maximum value of the at least one characteristic in one of (i) a running-in phase of the guide component, and (ii) at the beginning of recordings of the guide component; and the analysis device is configured to output one of an alarm and a third warning in response to at least one condition being fulfilled, the at least one condition including at least one of (i) after the further warning, a predetermined number of cycles being reached, (ii) an estimated remaining service life being reached, (iii) the at least one characteristic exceeding a determined statistical limit, and (iv) one of an absolute limit, a configurable limit, and a threshold value for the at least one characteristic being reached.

12. The guide according to claim 7, wherein: the analysis device is configured to presume a non-change of the at least one characteristic if it is at least one of (i) below an upper limit, (ii) above a lower limit, and (iii) between two limits; and the analysis device is configured to compute and adaptively adjust at least one of (i) the upper limit, (ii) the lower limit, and (iii) the two limits using the at least one characteristic.

13. The guide according to claim 1, wherein the analysis device is configured to perform the fatigue detection in a location-resolved manner.

14. A sensor assembly for a guide having a guide part and a guide component configured to be guided and movable via the guide part, the sensor assembly comprising: a sensor configured to detect a vibration signal of the guide component; and an analysis device configured to analyze the vibration signal detected by the sensor, the analysis device being configured to determine a movement profile of the guide component based on the vibration signal detected by the sensor and perform fatigue detection using the vibration signal of a part of the movement profile

15. A method using a sensor assembly for a guide having a guide part and a guide component configured to be guided and movable via the guide part, the sensor assembly having a sensor configured to detect a vibration signal of the guide component and an analysis device configured to analyze the vibration signal detected by the sensor, the method comprising at least one of: determining a movement profile of the guide component based on the vibration signal detected by the sensor and performing fatigue detection using the vibration signal of a part of the movement profile; digitally filtering the vibration signal detected by the sensor and determining the movement profile of the guide component based on the digitally filtered vibration signal; and determining a frequency band of the vibration signal and performing the fatigue detection using the frequency band.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Preferred exemplary embodiments of the disclosure will be explained in greater detail hereafter on the basis of schematic drawings. In the figures:

[0057] FIG. 1a shows a perspective illustration of a guide according to one exemplary embodiment,

[0058] FIG. 1b shows the guide from FIG. 1a in a side view,

[0059] FIG. 2a shows a perspective illustration of a part of a guide together with a sensor assembly,

[0060] FIG. 2b shows a perspective illustration of a guide according to a further exemplary embodiment,

[0061] FIG. 3 shows a flow chart of a functional description of the guide according to the exemplary embodiments,

[0062] FIG. 4 shows a vibration signal detectable via a sensor of the guide according to the exemplary embodiments,

[0063] FIG. 5 shows a diagram of a starting and acceleration phase of the guide for different velocities,

[0064] FIG. 6 shows a diagram of analysis results of a fatigue detection of the guide, and

[0065] FIG. 7 shows the diagram from FIG. 6 with warning limits indicated.

DETAILED DESCRIPTION

[0066] According to FIG. 1a, a guide according to one exemplary embodiment has a guide part in the form of a guide spindle 1 and a guide component in the form of a ballscrew nut 2. A housing 4 is fastened on a flange of the ballscrew nut 2 on an end face facing in the axial direction. A sensor 6 is provided in this housing, which is schematically shown in FIG. 1a. A vibration signal of the guide can be detected using this sensor. Furthermore, an analysis device 8 in the form of a microcontroller is provided, which is also schematically shown in FIG. 1a and is connected to the sensor 6. Furthermore, the analysis device 8 is connected to an energy generating unit 10, wherein this is also schematically shown. It is recognizable according to FIGS. 1a and 1b that the housing 4 is designed in a shell shape and the diameter corresponds to that of the ballscrew nut 2. The shell-shaped housing 4 encloses the guide spindle 1 in this case.

[0067] According to FIGS. 2a and 2b, a further embodiment of a guide having a guide part in the form of a guide rail 12 and a guide component in the form of a guide carriage 14 is provided. A housing 16 is designed U-shaped in this case and in particular has a sensor, an analysis device, and an energy generating unit corresponding to FIG. 1a. The housing 16 can be fastened on an end face 18 of the guide carriage 14 facing in the axial direction. In the radial direction, the housing 16 does not protrude beyond the guide carriage 14 in this case. Due to the U-shaped design of the housing 16, it can advantageously enclose the guide rail 12. If the guide rail 12 has a profile, corresponding to FIG. 2a, the housing 16 can thus engage in the profile with a corresponding profile. According to the flow chart in FIG. 3a, a measurement 20 is identified with a first block. During the measurement, a vibration signal is detected by the sensor 6, see FIG. 1a. This is apparent in FIG. 4 and is provided with the reference sign 22. The vibration signal 22 is plotted in a diagram, wherein the abscissa shows the number of the measurements and the ordinate shows a scaled amplitude of the vibration signal 22. According to FIG. 3, after the measurement 22, a determination of a movement profile is carried out based on the vibration signal 22 in the block 24. For this purpose, the vibration signal 22 is digitally filtered via a low-pass filter, whereby a movement profile 26 is recognizable according to FIG. 4. This profile has multiple parts. According to FIG. 4, a standstill profile is shown by the number 1, a starting profile is shown by the number 2, an acceleration profile is shown by the number 3, a profile of constant velocity is shown by the number 4, and a braking profile is shown by the number 5. The fatigue detection is carried out in particular in the profile having the constant velocity to avoid undesired acceleration influences, because of which it is extremely advantageous to detect the different parts of the movement profile by way of the analysis device 8, see FIG. 1a. The velocity of the ballscrew nut 2 or the guide carriage 14, respectively, see FIGS. 1a and 2b, is determined in the profile of constant velocity on the basis of the standstill profile and/or the starting profile. This is explained in greater detail in FIG. 5. The starting and acceleration phase of the linear movement is shown therein by different achieved velocities of the phase having the constant velocity. A time in seconds is plotted on an abscissa in this case and an amplitude is plotted on an ordinate. A curve 28 shows in this case the starting and acceleration phase in the case of a revolution of a drive motor at 50 RPM. A further curve 30 shows the starting and acceleration phase in this case at 300 RPM and a curve 32 shows the starting and acceleration phase at 1000 RPM. The computation of the velocity is preferably performed using the sections of the curves 28, 30, or 32 which are above a threshold value 34.

[0068] According to FIG. 3, a block 36, in which a frequency band of the vibration signal 22 is determined, follows after the block 24, wherein the frequency band is used for the fatigue detection by the analysis device 8, see FIG. 1a. The frequency band is estimated on the basis of the computed velocity and is purged of the frequency bands which are not required by filters, see block 38 in FIG. 3.

[0069] A computation of relevant characteristics of the frequency band worked out in the block 38 is carried out in the following block 40 in FIG. 3. A mean value or an MAD or RMS value can be provided as characteristics, for example. After the block 40, a block 42 can be provided, in which a scaling of the computed characteristics to the computed velocities is provided, so that effects of different velocities can be compensated for. A signal analysis subsequently follows in the block 44. For this purpose, the determined characteristics are combined, as explained at the outset, and the combined characteristic is compared to previously determined characteristics. If a slope of the characteristic or an increase of the characteristic greater than 0 is provided, the method according to FIG. 3 having the left branch 46 is thus provided. If the characteristic remains equal or decreases, the method thus continues according to FIG. 3 with the right branch 48. In the branch 48, it is studied in the block 50 whether the guide from FIGS. 1 to 2 is in a stable phase, i.e. no fatigue exists and the running-in phase is ended. If a stable phase is not provided, the running-in phase is thus recognized by the analysis device 8 according to FIG. 3 in block 52 and subsequently a new measurement is initiated in the block 54. The combined characteristic decreases during the running-in phase. If the characteristic remains equal, the block 56 provided in FIG. 3 thus follows after the block 50. The limits of the stable phase are adaptively adjusted therein if needed and a new measurement is subsequently initiated with the block 54.

[0070] The determined combined characteristics are shown according to FIG. 6. The measurement number is shown on the abscissa and the scaled value of the combined characteristic is shown on the ordinate. It is recognizable in the running-in phase 58 that the combined characteristics sink proceeding from a starting level 60 of the running-in phase. Subsequently, a stable phase 62 takes place, in which the combined characteristics remain equal or remain approximately equal within adaptively changeable limits 64 and 66. If the combined characteristics increase, a fatigue phase 68 is thus recognized by the analysis device 8. This means if an increase of the combined characteristics is established in block 44 according to FIG. 3, the method is thus continued in the left branch 46. Firstly, it is established in block 69 whether the increase of the combined characteristic is greater than 56, i.e. it is established using statistical means whether an increase takes place. If this is not the case, an outlier counter is thus reduced by one point in block 70. The limits 64, 66 are subsequently again adaptively adjusted in the block 56, see FIG. 6. If the result of the statistical analysis in the block 69 is such that the increase of the combined characteristic is 56, in the block 72 the outlier counter is thus increased by one point. In the following block 74 it is then established whether the number of the outliers has exceeded a determined threshold value. If this is not the case, a new measurement is thus initiated in the block 54. However, if this is the case, it is thus determined in the block 46 whether the scaled value of the combined characteristic is greater than the starting level 60, see FIG. 6. If this is not the case, a warning level 1 is then output in the block 78. If this is the case, the check thus follows in the block 79 as to whether a limiting value is exceeded. The limiting value is, for example, an estimated remaining service life or an absolute threshold value or the limiting values listed in the introduction to the description. If the limiting value is exceeded, an alarm is then output in the block 80. If the limiting value is not exceeded, a warning level 2 is then output in the block 82. This is schematically shown in FIG. 7. In this case, the various warning levels and the alarm are shown based on FIG. 6. If the conditions explained according to FIG. 3 are fulfilled, an alarm is thus output in the range 84. A warning level 2 takes place in the range 86, a warning level 1 takes place in the range 88, and no warning or no alarm takes place in the range 90.

[0071] A sensor assembly, in particular for a guide, is provided according to the disclosure, which has a sensor and an analysis device. The analysis device determines a movement profile of the guide component based on a vibration signal detected by the sensor, wherein a part of the movement profile is used for fatigue detection. Alternatively or additionally, it can be provided that the vibration signal detected by the sensor is filtered or digitally filtered and the or a movement profile of the guide component is determined based on the filtered or digitally filtered signal.

LIST OF REFERENCE NUMERALS

[0072] 1 guide spindle [0073] 2 ballscrew nut [0074] 4; 16 housing [0075] 6 sensor [0076] 8 analysis device [0077] 10 energy generating unit [0078] 12 guide rail [0079] 14 guide carriage [0080] 18 end face [0081] 20 measurement [0082] 22 vibration signal [0083] 24, 36, 38, 40, 42, 44, 50, 52, 54, 56, 69, 70, 72, 74, 76, 78, 79, 80, 82 block [0084] 26 movement profile [0085] 28, 30, 32 curve [0086] 34 threshold value [0087] 46 left branch [0088] 48 right branch [0089] 58 running-in phase [0090] 60 starting level [0091] 62 stable phase [0092] 64, 66 limit [0093] 68 fatigue phase [0094] 84, 86, 88, 90 range