JP2621990B2 - Diagnosis method of mechanical system operated by hydraulic servo system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method of diagnosing a mechanical system, which is suitable for use when operating a mechanical system with a hydraulic servo system.

[Prior art]

Generally, hydraulic pressure is used as an actuator for operating a huge mass (mass), and a high response can be obtained by adding a servo mechanism using a servo valve or the like. It is possible to construct a hydraulic servo system. However, in equipment that employs such a system, rattling may occur in the mechanical system due to mechanical wear and the like, but such lash is the largest factor that significantly slows down responsiveness. Is the item that needs to be implemented. FIG. 9 shows a pressing roller (hereinafter, referred to as a wrapper roll) provided in a strip winding facility in a steel hot rolling line as an example of a mechanical facility whose driving is controlled by a hydraulic servo system. In FIG. 9, reference numeral 10 denotes ratsuparol,
Reference numeral 12 denotes a frame that rotates around the center axis 14 to support the wrapper roll 10, 16 denotes a hydraulic cylinder that rotates the frame 12 to change the position of the wrapper roll 10, and 18 denotes a hydraulic cylinder that A shaft 20 for mounting the rod to the frame 12 is a fixed end of the hydraulic cylinder 16. In the strip winding device having such a wrapper roll 10, in order to perform the step avoidance control, it is necessary to detect a step at the end and to repeat the avoidance and pressing of the wrapper roll 10 with high response, so that the mechanical system including the frame 12 is required. Is controlled by a hydraulic servo system including a hydraulic cylinder 16. In this hydraulic servo system, the amount of oil to the cylinder 16 is controlled by, for example, the opening of a servo valve. Conventionally, as shown in FIG. 9, a method of controlling the amount of play of the winding equipment is as follows.
In this manner, the zipper roll 10 is zippered with a pressing force that does not cause mechanical strain and absorbs rattle, and then the zipper roll 10 is measured to obtain the amount of backlash and manage the zipper roll. There is.

[Problems to be solved by the invention]

However, the conventional method of managing the amount of backlash requires a hydraulic jack or the like, so that the measuring device becomes large and the measuring cost increases. In addition, it is difficult to appropriately measure the jack-up and the amount thereof in a short time, so that a long time is required for the measurement. Further, since the measurement cannot be performed at the same time when the mechanical system is driven, there is a problem that the measurement time is restricted. Therefore, in reality, frequent measurements cannot be made. Furthermore, in the above method, there is a problem that the measurement accuracy is poor because the influence of the distortion or bending of the mechanical system due to the pressing force appears strongly in the measurement result. The present invention has been made in view of the above-mentioned conventional problems, and does not require large-scale facilities, has a short measurement time, and has no restriction on measurement timing, and accurately removes mechanical systems. An object of the present invention is to provide a diagnostic method capable of performing a diagnosis.

[Means for achieving the object]

The present invention, when operating a mechanical system with a hydraulic servo system,
The hydraulic servo system is vibrated with a sine wave having a frequency that the system can follow, and a waveform indicating the amount of oil flowing in the vibrated hydraulic servo system is compared with a waveform indicating the position of the mechanical system, whereby The above object has been attained by determining the presence or absence of play in the mechanical system and calculating the amount of play.

[Action]

Hereinafter, the principle of the present invention will be described. Mechanical equipment having a hydraulic servo system includes, for example,
There is a winding equipment provided with a wrapper roll 10 as shown in the figure. In this winding equipment, as shown in FIG. 1, there is a gap between the center shaft 14 and the frame 12 and between the mounting shaft 18 and the frame 12. When this occurs, the play k causes the response to slow. The center shaft 14 is provided with a detector 12A for detecting the angle, and the position h of the mechanical system can be converted from the angle. In addition, oil flows into and out of the cylinder 16 from the servo valve 35A, and the position g of the servo valve 35A is detected by a position detector 35B. FIG. 2 is a system diagram of a hydraulic servo system 23 provided in such a winding facility and for performing step-avoidance control using a wrapper roll when winding the strip. In FIG. 2, reference numeral 24 denotes a control gain Kc, and 26 denotes a servo system gain.
Ks, 28 is a hydraulic gain Kh, 30 is a cylinder element, 32 is a play element, 34 and 36 are angle h 'signals of the central shaft 14 corresponding to the position h of the mechanical system, and correspond to the amount of oil flowing in the hydraulic system. Servo valve 35
This is an addition point for feeding back the spool position g signal of A. Here, consider a case where the hydraulic servo system 23 shown in FIG. 2 is vibrated by inputting a sine wave signal a having a frequency that can be sufficiently followed by the system. With respect to the sine wave signal a input at that time, the servo valve spool position g is shown in FIG.
Sine wave as shown in Fig.
If there is, the mechanical system position h changes in a waveform in which the upper and lower limits of the sine wave are flat as shown in FIG. 3 (B). The fact that the servo valve spool position g and the mechanical system position h change in the above-described relationship is theoretically proved as follows. First, a sine wave signal having a frequency that can sufficiently follow the hydraulic servo system 23 is input and vibrated. Therefore, this hydraulic servo system is approximated by a proportional system having no phase delay as shown in FIG. can do. In this approximated hydraulic servo system, the input is x (t) = Xsin ωt and the output is y
If (t) is set, the relationship between the input x (t) and the output y (t) is as shown in FIG. Also, the input x (t)
The relational expression between the output and the output y (t) can be expressed by the following expressions (1) to (3) at each time point. y (t) = k (X sinωt−B) (0 ≦ ωt ≦ π / 2) (1) y (t) = k (X−B) (π / 2 <ωt ≦ π−α) (2 ) Y (t) = k (X sin ωt + B) (π−α ≦ ωt ≦ π) (3) where X and B are constants, α is a phase angle, and from the relationship of the following equation (4), It is represented by (5). Xsin (π−α) = X−2B (4) α = sin ⁻¹ {(X−2B) / X} (5) That is, in the period of π / 2 <ωt ≦ π−α, the time t
A flat portion (flat portion) l in which the mechanical system position h does not change regardless of the change in. Therefore, by paying attention to the flat portion l, it is possible to determine the presence or absence of mechanical backlash. As shown in FIG. 6, it is also possible to calculate the backlash by analyzing and calculating the servo system spool position g in comparison with the mechanical system position h. Considering that the time integral of the spool position g of the servo valve corresponds to the amount of oil flowing into the cylinder as in the following equation (6), the amount of play in the mechanical system is as shown in FIG. From the relationship between the amplitude of the position, the oil amount n when the operation is not performed due to the play, and the oil amount m for operating by the amplitude, the following expression (7) is used. (Oil amount ≒ [spool position] dt) (6) Backlash amount k = · (n / m) (7) The present invention has been made based on the above findings. As described above, the diagnosis can be performed without the need for hydraulic jacks, etc., so that the equipment is not large and the cost of the diagnosis can be reduced, and the measurement time can be reduced to about several seconds. The measurement time can be drastically reduced as compared with the technology, the measurement timing is not restricted, frequent measurement can be performed, and the influence of mechanical system distortion, bending, etc. is smaller than that of the conventional technology. ,
Measurement accuracy can be improved. When the present invention is adopted and the mechanical system operated by the hydraulic servo system having the servo valve is back-diagnosed, the amount of oil flowing through the hydraulic servo system is detected by the spool position of the servo valve. Diagnosis of ye can be made. Also, in a hydraulic servo system having a flow control valve such as a proportional solenoid valve, the amount of flowing oil can be detected by an appropriate method such as detection of a valve opening degree to make a diagnosis.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, as shown in FIG. 1 above, in a wrapper roll 10 provided in a winding facility in a steel hot rolling line, as shown in FIG. This is a diagnostic device 37 installed in the hydraulic servo system for diagnosing. The rattling diagnostic device 37 mainly includes a sine wave oscillating unit 38 for inputting the sine wave signal a to the hydraulic servo system 23,
The spool position sampling unit 40 for sampling the spool position g of the servo valve 35A detected by the position detector 35B shown in the figure, and the angle h 'of the center shaft 14 detected by the position detector 12A shown in FIG. A mechanical system position sampling unit 42 for sampling the system position h) and an analyzing unit 44 for analyzing the sampling data collected by each of the sampling units 40 and 42 and detecting the mechanical system play. If there is any backlash, a calculation unit 46 for calculating the amount of backlash, and a display unit 48 for displaying the occurrence of the backlash calculated and calculated by the analysis unit 44 and the calculation unit 46 and the backlash. It is composed of Hereinafter, the operation of the embodiment will be described. 7, first, a sine wave signal a having a frequency sufficient for the servo system 23 to follow is input from the sine wave oscillating section 38 to the hydraulic servo system 23 to generate vibration. I do. At that time, the detection signals of the servo valve spool position g and the mechanical system position h detected by the respective position detectors 35B and 12A are sampled by the spool position sampling unit 40 and the mechanical system position sampling unit 42 within a certain period. accumulate. Next, the stored data is analyzed by the analysis unit 44, and it is determined whether or not a flat portion l exists in the data of the mechanical system position h. If this part 1 exists, it is determined that play has occurred. In this case, together with the data of 1 and the data of the servo valve spool position g, the calculation unit 46 executes the calculation of the amount of backlash as shown in the above equation (7). The result of these determinations and the result of the calculation of the amount of play are displayed on the display unit 48. The operator can know the play from the display result on the display unit 48, and can judge the necessity of maintenance and inspection of the wrapper roll 10. Next, FIG. 8 shows the results of diagnosing rattrapol rattle by employing the present invention. When a sine wave signal is input as shown in FIG. 8 (A), the spool position g of the servo valve changes in synchronization with the input as shown in FIG. 8 (B). On the other hand, as shown in FIG. 8 (C), the upper and lower limit positions of the mechanical system position h are flat. 8 (B) and 8 (C), the amount of oil in the cycles of steps A to D is obtained for three cycles, and the amount of oil obtained from the oil amount by the above equation (7) is calculated as shown in FIG. ). Therefore, it can be seen that the presence and amount of play can be accurately diagnosed according to the present invention. In the above-described embodiment, the present invention has been described with reference to a wrapper roll in a winding facility of a steel hot rolling line. Can also be adopted for the mechanical system of other equipment operated by. Further, in the above-described embodiment, the case where the servo valve is used in the hydraulic servo system has been described as an example. However, the hydraulic servo system is not limited to the one using such a servo valve. If a hydraulic servo system is used, the present invention can be used to diagnose mechanical system play. For example, the present invention can also be applied to a hydraulic servo system using another flow control valve using a proportional solenoid valve or the like, so that the play of a mechanical system can be diagnosed.

【The invention's effect】

As described above, according to the present invention, the play of the mechanical system can be diagnosed without requiring large-scale equipment, with a short measurement time, and with no restriction on the measurement timing. Therefore, frequent diagnosing is possible. In addition, since there is little influence of distortion or bending of the mechanical system, excellent effects such as improvement of measurement accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration example of a wrapper roll and a servo valve for explaining the principle of the present invention, FIG. 2 is a block diagram showing a hydraulic servo system of the wrapper roll, and FIG. Fig. 4 is a diagram showing an example of position data of a hydraulic servo system and a mechanical system, and Fig. 4 is a block diagram showing an input-output relationship of a simplified hydraulic servo system according to the present invention. FIG. 5 is a diagram showing the input and output relationship, FIG. 6 is a diagram for explaining the calculation of the amount of rattling from the input and output relationship, and FIG. FIG. 8 is a block diagram showing a configuration of a diagnostic device according to an embodiment, FIG. 8 is a diagram showing an example of a result of diagnosing rattle according to the present invention, and FIG. 9 is a diagram provided on a conventional wrapper roll. It is sectional drawing which shows the example of a structure of a diagnostic device. 10… Rasp roll, 12… Frame, 12A… Angle detector of center shaft 14, 16… Hydraulic cylinder, 18… Mounting shaft, 23… Hydraulic servo system, 35B… Servo valve position detector, 37 …………………………………………………… …………………………………………………………………………………………………………………………… …… サ ー ボ 弁 サ ー ボ サ ー ボ サ ー ボ

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-52887 (JP, A) JP-A-61-201978 (JP, A) JP-A-3-77757 (JP, A) JP-A-2- 278137 (JP, A) Jiko 50-18076 (JP, Y1) JP-B 51-37547 (JP, B2)

Claims (1)

(57) [Claims] When a mechanical system is operated by a hydraulic servo system, the hydraulic servo system is vibrated by a sine wave having a frequency that the system can follow, and the amount of oil flowing through the vibrated hydraulic servo system is indicated. A machine operated by a hydraulic servo system, characterized in that by comparing the waveform with a waveform indicating the position of the mechanical system, the presence or absence of play in the mechanical system is determined, and the amount of play is calculated. Diagnosis method of system.