Aviation engine casing internal foreign object positioning and detection system and detection method

Abstract

The present invention discloses a positioning and detection system and a detection method for foreign objects inside an aero-engine casing. The detection system consists of a detector, a signal conditioning unit, a data acquisition card and an upper computer; the detector includes a pair of X-ray detectors or ultrasonic detectors arranged oppositely; a biaxial servo motor is arranged on the side of the X-ray detector or ultrasonic detector away from the casing; the biaxial servo motor is fixedly arranged on a base; an extension plate located directly below the casing is fixedly arranged at the bottom of the base, and a holding structure for ensuring that the two detectors are always on the diameter of the cylindrical or conical casing of the casing is arranged on the base or the extension plate; for the detection method, the detector collects signals and converts them into voltage signals, and after being amplified by the signal conditioning unit, the foreign object signals are transmitted to the upper computer by the data acquisition card, and the upper computer extracts typical characteristic quantities to determine the information of the foreign objects in the product to be measured. The present invention can reduce the determination factors affecting the detection results of engine foreign objects.

Description

Technical Field

[0001] The invention relates to testing or analyzing materials by means of measuring the chemical or physical properties of materials, and in particular to a redundant object positioning detection system and a detection method inside an aircraft engine casing. Background Art

[0002] The casing is one of the important parts of an aircraft engine. It is the base of the entire engine and the main load-bearing component on the aircraft engine. Its appearance and structure are complex. Different engines and different parts of the engine have different casing shapes. The functions of the casing parts determine the shape of the casing, but their basic characteristics are components composed of cylindrical or conical shells and support plates. The casing is like a screw on an airplane. Although it is inconspicuous, it is indispensable. From the experience of engine use, among the many factors affecting its quality, excess is one of the main reasons. Excess can cause serious consequences such as engine shutdown, severe wear of bearings, and failure of key functions, and ultimately lead to fatal accidents such as aircraft inability to control and crash. As the performance of the engine continues to improve and its functions continue to increase, its structure has become more and more complex; the production, processing, assembly and other processes of the engine are becoming increasingly complex, and the probability of generating and carrying excess in each link has also increased accordingly. On the other hand, the lack of technical standards for the control, inspection and elimination of excess in actual production has also increased the difficulty of excess control.

[0003] The engine is often under high acceleration or severe impact during operation. The movement of excess material is very random. It may be suspended in the cavity or fall on certain contact parts, which may cause circuit short circuit, pipeline blockage and jam of operating parts, leading to flight test failure and serious aerospace accidents. Therefore, the detection of excess material is an important part of the design and test process of aerospace engines.

[0004] At present, the detection of excess matter in the casing of an aircraft engine generally uses the rotation of the casing to monitor the signal of the movement of excess matter in the casing, but it is easy to misjudge and affect the determination of the engine excess matter detection result. For example, in the prior art, Niu Shufeng mentioned in the paper "Automatic Detection Technology of Excess Matter in Liquid Oxygen / Kerosene Engines" published in Volume 45, Issue 4 of "Rocket Propulsion" in August 2019: The floating ring in the turbine pump will make a sound from time to time during the rotation of the engine. Due to the large size and weight of the floating ring, multiple sensors of the excess matter detection system can detect the floating ring sound signal, and the detection system determines it as excess matter, which affects the determination of the engine excess matter detection result. For example, in the prior art, Qi Le mentioned in the paper "Automatic Detection System for Excess Matter in Aerospace Engines" published in Volume 34, Issue 1 of "Aerospace Measurement Technology" in February 2014: The system pulse extraction algorithm selects an appropriate voltage threshold, extracts pulse signals with voltage exceeding the threshold, and calculates the energy characteristics of the pulse signal, filters out the influence of electromagnetic interference and system background noise, and finally determines whether excess matter exists. Therefore, this method of monitoring the sound of the superfluous matter by rotating the casing also has the influence of removing background noise, etc., which makes the detection process very troublesome. In addition, the positioning of the superfluous matter is also prone to misjudgment. Due to the rotation of the casing, the positioning of the superfluous matter also makes its positioning detection a very complicated detection process. The prior art "Automatic Detection System for Superfluous Matter in Aerospace Engines" also mentioned: In order to achieve the positioning of superfluous matter, it is necessary to determine the position of the tail nozzle where the superfluous matter is located. The acoustic emission sensor is installed on the six tail nozzles of the engine, and four types of steel balls with diameters of 0.5mm, 1.0mm, 1.5mm, and 2.0mm are implanted in the interior of one tail nozzle in turn to obtain multi-channel superfluous matter collision signals under different speed test conditions. It can be seen that in order to complete the positioning detection of superfluous matter, it is necessary to put steel balls in the test piece, and the process is indeed troublesome and troublesome. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects existing in the prior art and provide a system for locating and detecting excess matter inside an aircraft engine casing, thereby avoiding the use of an acoustic emission sensor in the prior art, which may cause misjudgment or affect the determination of the engine excess matter detection result due to the sound emitted by the casing itself when it rotates, and making the positioning detection of excess matter a simple detection process.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is to design a redundant object positioning detection system inside an aircraft engine casing, which is composed of a detector, a signal conditioning unit, a data acquisition card and a host machine which are arranged in sequence;

[0007] The detector is an industrial computer tomography imaging device;

[0008] Or the detector includes a pair of X-ray detectors or a pair of ultrasonic detectors arranged oppositely on the outside of the aircraft engine casing; a dual-axis servo motor is arranged on the side of the X-ray detector or ultrasonic detector away from the casing, and the two output shafts are respectively connected to a screw nut mechanism through a connecting structure, and the nuts of the two screw nut mechanisms are simultaneously fixedly connected to a ring larger in size than the casing, and the ring is concentrically arranged with the cylindrical or conical shell of the casing, and the detector that can slide on the ring is arranged on the ring; the dual-axis servo motor is fixedly arranged on the base, and the base is located on the side of the X-ray detector or ultrasonic detector away from the casing; an extension plate located directly below the casing is fixedly arranged at the bottom of the base, and a retaining structure for ensuring that the two detectors are always on the diameter of the cylindrical or conical shell of the casing is arranged on the base or extension plate. Industrial computer tomography imaging equipment clearly, accurately and intuitively displays the internal structure, composition, material and defect status of the object being detected in the form of two-dimensional tomographic images or three-dimensional stereo images. In this way, the image of the inside of the aircraft engine casing can be directly obtained through industrial CT to know whether there is any excess material and its location information, without rotating the casing, and avoiding the influence of rotating the casing as in the prior art.

[0009] The detector collects the signal and converts it into a voltage signal output. After amplification by the signal conditioning unit, the data acquisition card transmits the excess signal to the host computer, extracts typical feature quantities, determines the presence or absence of excess in the product being tested, the particle size (the particle size is an initial estimate, and the size of the excess is estimated based on the moving distance of the detector) and its spatial position, and realizes automatic detection of excess. Although the shapes of aircraft engine casings of different types and models are different, their basic characteristics are that they are composed of cylindrical or conical shells and support plates; therefore, circumferential detection at the same position is used, especially when the internal structure is symmetrical according to the drawings, the detected signals are different, which can indicate the presence of excess in the casing. This setting ensures that the two sensors must be symmetrical, that is, they must be located on the diameter of the cylindrical or conical shell of the casing, thus ensuring the accuracy of the detection. After a pair of detectors relatively arranged outside the aircraft engine casing rotate one circle to perform a circumferential inspection, the detectors are driven by a dual-axis servo motor to move in the length direction (or height direction) of the casing and then perform a circumferential inspection at the next position, finally completing the inspection of the entire aircraft engine casing.

[0010] A further technical solution is that the signal conditioning unit includes a conditioning circuit, and the conditioning circuit includes a filter and a power amplifier. A preamplifier can also be set between the detector and the signal conditioning unit to amplify the detected signal. The connection structure includes a reducer, and the two output shafts of the dual-axis servo motor are respectively connected to a reducer, and the output shaft of each reducer is connected to a screw nut mechanism through a bevel gear set, which is a prior art and will not be repeated.

[0011] A further technical solution is that a pair of sliders are slidably arranged on the ring, a slot is arranged on the slider, the slot opening is arranged facing the center of the ring, a spring is fixedly arranged on the bottom wall of the slot, the other end of the spring is fixedly connected to the detector, and the tail of the detector is slidably arranged in the slot. A slide groove for the slider to slide is arranged on the ring, so that the detector can move with the slider when it moves, and the detector can rotate at a certain angle at the same time; the detector can achieve its detection head against the outer surface of the casing through the spring.

[0012] A further technical solution is that the retaining structure includes an annular groove arranged on the extension plate, the annular groove is arranged to match the circular ring, a disc-shaped cavity connected to the annular groove is also arranged in the extension plate, the bottom wall of the disc-shaped cavity is flush with the bottom wall of the annular groove, a rectangular plate is rotatably arranged in the disc-shaped cavity, the part of the rectangular plate located in the annular groove is fixedly connected with a connecting plate, the length of the connecting plate is greater than the length of the casing, and an opening for the connecting plate to pass through is arranged on the slider, and the shape of the opening is adapted to the shape of the connecting plate. The thickness of the rectangular plate matches the thickness of the disc-shaped cavity or is slightly smaller than the thickness of the disc-shaped cavity; a rotating shaft is fixedly arranged on the inner top wall of the disc-shaped cavity, the rectangular plate is rotatably connected to the rotating shaft, and the center of the rectangular plate is consistent with the position of the rotating shaft; the rotating shaft is located on the rotation axis of the cylindrical or conical shell of the casing; the side end surface of the slider facing the center of the circular ring exceeds the slide groove setting to facilitate the connecting plate to pass through the slider. After this arrangement, since the detector is set on the slider, and the slider is connected to the connecting plate and the rectangular plate, the rectangular plate rotates the slider at the same angle in the same direction at the same time. This can keep the two relatively set detectors always on the diameter of the cylindrical or conical outer shell of the receiver.

[0013] The present invention also provides a technical solution, which is a method for locating and detecting excess matter inside an aircraft engine casing. The detection system adopts the detection steps performed in sequence as follows: the detector collects signals and converts them into voltage signals, which are amplified by a signal conditioning unit, and then the excess matter signals are transmitted to a host computer by a data acquisition card. The host computer extracts typical feature quantities, determines the presence or absence of excess matter in the product being tested, the particle size and its spatial position information, and realizes automatic detection of excess matter.

[0014] A further technical solution is that, according to the drawings of the aircraft engine casing, for the area of ​​symmetrical structure, the detection step of the signal collection of the detector is: rotating the rectangular plate at a certain angle to detect a pair of relatively set fan-shaped areas. If it is found that there is a mismatch in the time of several reflections, it means that there is excess material, or according to the waveform, the relatively set ultrasonic detectors detect in sequence and emit ultrasonic waves in sequence. If the waveform emitted by a single detector is asymmetrical, but the waveforms of the two detectors are symmetrical, it means that there is excess material in the detected area; continue to rotate the rectangular plate at a certain angle to detect the next pair of relatively set fan-shaped areas, repeat the above process until the rectangular plate returns to the initial position, and the detection is completed. The detection system rotates one circle in the circumference for detection (rather than the casing rotation) to avoid the change of the position of the excess material; avoid the use of acoustic emission sensors in the prior art, which may cause misjudgment or affect the determination of the engine excess material detection results due to the sound emitted by the casing itself, and make the positioning detection of the excess material a simple detection process. Before testing, the aircraft engine casing drawings can be used to identify which areas of the casing have symmetrical internal structures and which areas have asymmetrical internal structures. This allows a preliminary understanding of the number of reflections and the numerical distribution of the reflection reception times before testing. If subsequent testing finds that the number of reflections has increased or that the distribution of reflection reception times is different from the distribution of reflection reception times inferred from the drawing structure, it can be determined that there is excess material.

[0015] A further technical solution is that, according to the aircraft engine casing drawings, for the area with asymmetric structure, the detector collects signal detection steps as follows: rotate the rectangular plate at a certain angle to detect a pair of relatively set fan-shaped areas. If it is found that the number of reflections is more than the number of reflections known from the drawings, it means that there are excess objects; further count the time differences between multiple reflections, and compare with the numerical distribution of the multiple reflection time differences inferred from the drawings to further determine the presence and location of excess objects.

[0016] The advantages and beneficial effects of the present invention are that the industrial computer tomography imaging equipment can clearly, accurately and intuitively display the internal structure, composition, material and defect status of the detected object in the form of a two-dimensional tomographic image or a three-dimensional stereoscopic image. In this way, the image status inside the aircraft engine casing can be directly obtained through industrial CT to know whether there are any extra objects and their location information, without rotating the casing, and avoiding the judgment influence caused by rotating the casing as in the prior art.

[0017] The detector collects the signal and converts it into a voltage signal output. After amplification by the signal conditioning unit, the data acquisition card transmits the excess signal to the host computer, extracts typical feature quantities, determines the presence or absence of excess in the product being tested, the particle size (the particle size is an initial estimate, and the size of the excess is estimated based on the moving distance of the detector) and its spatial position, and realizes automatic detection of excess. Although the shapes of aircraft engine casings of different types and models are different, their basic characteristics are that they are composed of cylindrical or conical shells and support plates; therefore, circumferential detection at the same position is used, especially when the internal structure is symmetrical according to the drawings, the detected signals are different, which can indicate the presence of excess in the casing. This setting ensures that the two sensors must be symmetrical, that is, they must be located on the diameter of the cylindrical or conical shell of the casing, thus ensuring the accuracy of the detection.

[0018] Since the detector is set on the slider, and the slider is connected to the connecting plate and the rectangular plate, the rectangular plate rotates the slider at the same angle in the same direction at the same time. This can keep the two relatively set detectors always on the diameter of the cylindrical or conical outer shell of the receiver.

[0019] The detection system rotates one circle for detection (rather than the casing rotation) to avoid the position change of the excess material; avoid the use of acoustic emission sensors as in the prior art, which may cause misjudgment or affect the determination of the engine excess material detection results due to the sound emitted by the casing itself when rotating, and make the positioning detection of excess material a simple detection process. Before the detection, according to the aircraft engine casing drawings, it can be clearly determined which areas of the casing have symmetrical internal structures and which areas have asymmetrical internal structures, so that before the detection, there is a preliminary understanding of the number of reflections and the numerical distribution of the reception time of several reflections. If the subsequent detection finds that the number of reflections increases or the distribution of the reception time of reflections is different from the distribution of the reception time of reflections inferred from the structure of the drawings, it can be determined that there is excess material. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of an embodiment 1 of a system for locating and detecting excess objects inside an aircraft engine casing of the present invention, in which a casing is detected;

[0021] Figure 2 yes Figure 1 Schematic diagram after removing the rectangular plate and connecting plate;

[0022] Figure 3 yes Figure 1 The middle extension plate shows an enlarged schematic diagram of the bolt and split position;

[0023] Figure 4 yes Figure 1 A three-dimensional schematic diagram of the middle receiver;

[0024] Figure 5 yes Figure 1 An enlarged schematic diagram of the middle receiver;

[0025] Figure 6 yes Figure 5 Middle AA section view

[0026] Figure 7 yes Figure 1 A magnified schematic diagram of the middle ring;

[0027] Figure 8 yes Figure 7 Only the schematic diagram behind the right end slider and the detector is shown;

[0028] Fig. 9 yes Figure 8 Exploded diagram of the middle slider, spring and detector;

[0029] Fig.10 yes Figure 1 Top view of the dual-axis servo motor;

[0030] Fig.11 yes Figure 1 An enlarged schematic diagram of the lower right corner;

[0031] Fig.12 yes Figure 1 A magnified view of the upper right corner.

[0032] In the figure: 1. casing; 2. detector; 3. dual-axis servo motor; 4. screw-nut mechanism; 5. ring; 6. base; 7. extension plate; 8. slider; 9. spring; 10. connecting plate; 11. ring groove; 12. disc-shaped cavity; 13. rectangular plate; 14. plate; 15. slide groove; 16. bolt. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0034] Embodiment 1: Figures 1 to 12 As shown (for ease of illustration, Figure 1The bolts, sliders and split positions are not shown). The present invention is a redundant object positioning detection system inside an aircraft engine casing, which is composed of a detector 2, a signal conditioning unit, a data acquisition card and a host computer arranged in sequence; the detector 2 includes a pair of X-ray detectors 2 arranged opposite to each other on the outside of the aircraft engine casing 1 or a pair of ultrasonic detectors 2 arranged opposite to each other on the outside of the aircraft engine casing 1; a dual-axis servo motor 3 is arranged on the side of the X-ray detector 2 or the ultrasonic detector 2 away from the casing 1, and the two output shafts are respectively connected to a screw nut mechanism 4 through a connecting structure, and the two The nuts of the screw nut mechanism 4 are fixedly connected to a ring 5 larger than the casing 1 in size. The ring 5 is concentrically arranged with the cylindrical or conical shell of the casing 1. The detector 2 that can slide on the ring 5 is arranged on the ring 5; the dual-axis servo motor 3 is fixedly arranged on the base 6, and the base 6 is located on the side of the X-ray detector 2 or the ultrasonic detector 2 away from the casing 1; the bottom of the base 6 is fixedly arranged with an extension plate 7 located directly below the casing 1, and the extension plate 7 is arranged with a retaining structure for ensuring that the two detectors 2 are always on the diameter of the cylindrical or conical shell of the casing 1. The signal conditioning unit includes a conditioning circuit, and the conditioning circuit includes a filter and a power amplifier. A pair of sliders 8 are slidably arranged on the ring 5, and a slot is arranged on the slider 8, and the slot is arranged facing the center of the ring 5. A spring 9 is fixedly arranged on the bottom wall of the slot, and the other end of the spring 9 is fixedly connected to the detector 2, and the tail of the detector 2 is slidably arranged in the slot. The holding structure includes an annular groove 11 arranged on the extension plate 7, the annular groove 11 is matched with the circular ring 5, and a disc-shaped cavity 12 connected to the annular groove 11 is also arranged in the extension plate 7, and the bottom wall of the disc-shaped cavity 12 is flush with the bottom wall of the groove 11, and a rectangular plate 13 is rotatably arranged in the disc-shaped cavity 12, and the part of the rectangular plate 13 located in the annular groove 11 is fixedly connected with a connecting plate 10, and the length of the connecting plate 10 is greater than the length of the casing 1, and an opening for the connecting plate 10 to pass through is arranged on the slider 8, and the shape of the opening is adapted to the shape of the connecting plate 10. The size of the circular ring 5 is larger than the size of the aircraft engine casing 1 of general specifications so as to adapt to the detection of casings of various sizes and specifications, and ensure that the circular ring can be sleeved on the outside of the casing.An identification layer is set at the center of the extension plate 7 to mark the center position of the extension plate for placing the casing 1, and the sizes of the base 6 and the extension plate meet the requirements that the center of the circular ring is consistent with the center of the extension plate; plates 14 are fixedly set at the upper and lower ends of the base, the screw of the screw nut mechanism is rotatably set on the two plates, and the nut of the screw nut mechanism is vertically slidably set on the slide groove (the casing is vertically set during detection, that is, the rotation center axis of the casing is vertically set), and the slide groove 15 is fixedly connected to the base or the upper and lower plates; a spacing is set between the top wall of the disc-shaped cavity and the upper surface of the extension plate; to facilitate the installation of the rectangular plate, the extension plate is divided into two left and right split types (the split extension plate can be connected or glued by bolts 16; the position of the left and right splits may not be located at the center position of the disc-shaped cavity of the extension plate 7, and may be slightly offset to avoid the rotating shaft), which is convenient for the rectangular plate 13 to be set in the disc-shaped cavity and for the rectangular plate to be rotatably installed on the rotating shaft. After the rectangular plate is installed on the rotating shaft, the lower end of the connecting plate is glued to the rectangular plate after passing through the annular groove. The rectangular plate can be rotated by manually turning the connecting plate, or the fixed setting of the rotating shaft can be changed to a method in which the rotating shaft is rotatably set on the inner top wall of the disc-shaped cavity, and the rotating shaft is fixedly connected to the rectangular plate. A reducer is then set in the extension plate, and the output shaft of the reducer is fixedly connected to the rotating shaft. Specifically, a accommodating cavity is set in the extension plate below the disc-shaped cavity, the reducer and the servo motor are set in the accommodating cavity, the reducer is driven by the servo motor, and then the automatic rotation of the rectangular plate is achieved by driving the servo motor.

[0035] The method for detecting the location of the excess in the casing 1 of an aircraft engine adopts the detection system, and is composed of the following detection steps performed in sequence: the detector 2 collects the signal and converts it into a voltage signal, and after amplification by the signal conditioning unit, the data acquisition card transmits the excess signal to the host computer, and the host computer extracts the typical characteristic quantity, determines the presence of excess in the product under test, the particle size and its spatial position information, and realizes the automatic detection of excess. According to the drawings of the casing 1 of the aircraft engine, for the area of ​​the symmetrical structure, the detection step of the signal acquisition of the detector 2 is: rotating the rectangular plate 13 at a certain angle to detect a pair of relatively set fan-shaped areas, if it is found that there is a mismatch in the time of several reflections, it means that there is excess, or according to the waveform, the relatively set ultrasonic detector 2 detects in sequence and emits ultrasonic waves in sequence, if the waveform emitted by a single detector 2 is asymmetric, but the waveforms of the two detectors 2 are symmetric, it means that there is excess in the detected area; continue to rotate the rectangular plate 13 at a certain angle to detect the next pair of relatively set fan-shaped areas, repeat the above process until the rectangular plate 13 returns to the initial position, and the detection is completed. According to the drawings of the aircraft engine casing 1, for the asymmetric structure area, the detection steps of the detector 2 for collecting signals are as follows: rotate the rectangular plate 13 at a certain angle to detect a pair of relatively set fan-shaped areas. If the number of reflections is found to be more than the number of reflections known from the drawings, it means that there are extra objects; further statistically calculate the time difference between multiple reflections, and compare it with the numerical distribution of the multiple reflection time differences inferred from the drawings to further determine the presence and location of the extra objects. Of course, in order to avoid the entanglement of the wires of the detector, after the circumferential detection of the casing at one height is completed, the detector reaches another height and rotates in the opposite direction for one circle to complete the detection of the inside of the casing at this height, and then rotates forward again after reaching another height. Repeating this process can avoid the entanglement of the wires.

[0036] Only two sensors (X-ray detector / ultrasonic detector) are set, one pair is symmetrically set on the outside of the casing, and the two sensors are moved in the same direction (for example, they rotate clockwise or counterclockwise at the same angle at the same time), and then the two sensors are moved to the next pair of detection fan-shaped areas, and one circle of detection is completed when they move to the initial position; then the sensors are moved to the position in the length direction of the casing and the above process is repeated;

[0037] (X-ray detectors are generally used to detect the internal structure of objects. It works by emitting a series of X-rays at the object, then receiving the X-rays reflected from the object, converting these rays into digital signals and storing them in a computer for subsequent use. Since X-rays can penetrate objects without being affected by them, X-ray detectors can clearly detect the internal structure of objects, thereby more accurately measuring the quality, size and defects of objects; ultrasonic detectors emit a beam of high-frequency ultrasonic pulses, which are reflected for the first time when they encounter the surface of the material being tested, and part of the energy continues to penetrate the material and is reflected again when it encounters the bottom surface (or internal interface) of the material. By measuring the time required for the ultrasonic pulse to be emitted and received (the time difference between two or more reflections); during detection, the number of reflections can be known for the symmetrical area. If the number of reflections increases, it means that there is excess material, or if it is found that the time of several reflections does not match, it means that there is excess material)

[0038] For the area with symmetrical structure, ultrasonic detectors set relatively to each other detect in turn. If it is found that there is a mismatch in the time of several reflections, it means that there are extra objects. Alternatively, ultrasonic detectors set relatively to each other detect in turn according to the waveform and emit ultrasonic waves. If the waveform emitted by a single detector is asymmetrical, but the waveforms of the two detectors are symmetrical, it means that there are extra objects in the detected area. This detection method reduces the subsequent waveform processing and reduces the equipment and components required for the entire detection system.

[0039] According to the drawings of the aircraft engine casing 1, for the area with asymmetric structure, the detection steps of the detector 2 for collecting signals are as follows: rotating the rectangular plate 13 at a certain angle to detect a pair of relatively set fan-shaped areas, if it is found that the number of reflections is more than the number of reflections known from the drawings, it means that there are redundant objects; further counting the time difference between multiple reflections, and comparing it with the numerical distribution of the multiple reflection time difference inferred from the drawings, if it is found that they are inconsistent (for example, according to the drawings, it is known that the structure at a certain height inside the casing is not symmetrical, and the reflection reception time detected by the ultrasonic waves emitted by the two relatively set detectors at this height of the casing should be 1, 2, 3 and 1, 1.7, 3 respectively; while the actual reflection reception time detected is 1, 2, 2.2, 3 and 1, 1.2, 2.3, 3 respectively), the presence and position of the redundant objects can be further determined. In this way, the detection method can self-check and ensure the accuracy of the detection, but compared with other detection methods, the required detection equipment is only ultrasonic detector or X-ray detector, the demand for equipment is not high, and the cost required for the entire detection is low. The number of detectors is also small, only two are needed, unlike some prior arts which require a large number of detectors, making installation and arrangement troublesome.

[0040] Embodiment 2: The difference from Embodiment 1 is that, in a method for detecting the positioning of excess matter inside an aircraft engine casing, after the casing is set vertically, the casing is first tilted and rotated so that the excess matter falls into the lower end of the casing or leaves the casing as much as possible, and then the casing is placed vertically and the bottom end of the casing is sealed (for example, the bottom end of the casing is sealed by gluing with a sealing film), wax is poured into the casing and cooled, so that the wax solidifies and the position of the excess matter cannot be changed, and then the casing is rotated (a pair of detectors are arranged opposite to each other outside the casing shell, and the detectors are fixed or the pair of detectors are rotated while the casing is rotated) (of course, since the sealing film is glued to seal the bottom end of the casing, the sealing film rotates with the casing), thereby improving the detection efficiency and reducing the detection time; the detection of excess matter positioning is also more accurate, and the detection method is no longer limited. The detection method of rotating the casing adopted in the prior art can also be well adapted, and after the detection is completed, the excess matter is taken out and then heated so that the wax melts and leaves the casing (which is also convenient for removing the excess matter), and the sealing film is torn off to remove the adhesive bonded to the bottom end of the casing.

[0041] Embodiment 3: The difference from Embodiment 1 is that, before the detector collects signals and converts them into voltage signals, the casing is first set vertically (meaning the casing is set vertically along its height direction), appropriately tilted and rotated at the same time, so that excess matter falls into the lower end of the casing or leaves the casing as much as possible, and then the casing is placed vertically and the bottom end of the casing is sealed (for example, the bottom end of the casing is sealed by gluing with a sealing film), and then wax is poured in and cooled so that the wax solidifies and the position of the excess matter cannot be changed, and then the center of gravity of the casing is detected: the center of gravity position of the casing of the original symmetrical structure is obtained through two suspensions, and then an industrial CT or ultrasonic detector or X-ray detector is used at the height of the center of gravity and at a certain height above and below the center of gravity to locally detect the casing, so as to reduce the detection time and improve the detection efficiency. By preliminarily determining the position of the excess matter and then detecting it through a modern detector, the efficiency is improved and the time is shortened.

[0042] If the receiver itself is an asymmetric structure, the center of gravity of the receiver can be pre-calculated or determined by computer based on the drawings and the materials used for its various parts. By using the same method as mentioned above, the inspection time can still be reduced and the inspection efficiency can be improved.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. The redundant object positioning and detection system inside the aircraft engine casing is characterized by: It is composed of a detector, a signal conditioning unit, a data acquisition card and a host computer which are arranged in sequence; The detector is an industrial computer tomography imaging device; Or the detector includes a pair of X-ray detectors arranged opposite to each other on the outside of the aircraft engine casing or a pair of ultrasonic detectors arranged opposite to each other on the outside of the aircraft engine casing; a double-axis servo motor is arranged on the side of the X-ray detector or the ultrasonic detector away from the casing, and the two output shafts are respectively connected to a screw nut mechanism through a connecting structure, and the nuts of the two screw nut mechanisms are simultaneously fixedly connected to a ring larger in size than the casing, the ring is concentrically arranged with the cylindrical or conical shell of the casing, and the detector that can slide on the ring is arranged on the ring; the double-axis servo motor is fixedly arranged on a base, and the base is located on the side of the X-ray detector or the ultrasonic detector away from the casing; an extension plate located directly below the casing is fixedly arranged at the bottom of the base, and a retaining structure for ensuring that the two detectors are always on the diameter of the cylindrical or conical shell of the casing is arranged on the base or the extension plate; The holding structure includes an annular groove arranged on the extension plate, the annular groove is matched with the circular ring, a disc-shaped cavity connected with the annular groove is also arranged in the extension plate, the bottom wall of the disc-shaped cavity is flush with the bottom wall of the annular groove, a rectangular plate is rotatably arranged in the disc-shaped cavity, a portion of the rectangular plate located in the annular groove is fixedly connected with a connecting plate, the length of the connecting plate is greater than the length of the casing, an opening for the connecting plate to pass through is arranged on the slider, and the shape of the opening is adapted to the shape of the connecting plate; A rotating shaft is fixedly arranged on the inner top wall of the disc-shaped cavity, and a rectangular plate is rotatably connected to the rotating shaft, and the center of the rectangular plate is consistent with the position of the rotating shaft; the position of the rotating shaft is located on the rotation axis of the cylindrical or conical shell of the casing; the side end surface of the slider facing the center of the ring exceeds the slide groove.

2. The system for locating and detecting excess objects inside an aircraft engine casing according to claim 1, characterized in that: The signal conditioning unit comprises a conditioning circuit, and the conditioning circuit comprises a filter and a power amplifier.

3. The system for locating and detecting excess objects inside an aircraft engine casing according to claim 2, characterized in that: A pair of sliders are slidably arranged on the circular ring, and a slot is arranged on the slider, and the slot opening is arranged facing the center of the circular ring. A spring is fixedly arranged on the bottom wall of the slot, and the other end of the spring is fixedly connected to the detector, and the tail of the detector is slidably arranged in the slot.

4. A method for locating and detecting excess material inside an aircraft engine casing, characterized in that: The detection system as claimed in claim 1 includes the following detection steps performed in sequence: the detector collects signals and converts them into voltage signals, which are amplified by the signal conditioning unit, and the data acquisition card transmits the excess signal to the host computer. The host computer extracts typical feature quantities, determines the presence of excess matter in the tested product, the particle size and its spatial position information, and realizes automatic detection of excess matter.

5. The method for locating and detecting excess matter inside an aircraft engine casing according to claim 4, characterized in that: According to the aircraft engine casing drawings, for the areas with symmetrical structures, the detector collects signals for detection in the following steps: rotating the rectangular plate at a certain angle to detect a pair of relatively set sector areas. If it is found that there is a mismatch in the reflection times, it means that there are extra objects. Alternatively, based on the waveform, relatively set ultrasonic detectors detect and emit ultrasonic waves in turn. If the waveform emitted by a single detector is asymmetrical, but the waveforms of the two detectors are symmetrical, it means that there are extra objects in the detected area. Continue to rotate the rectangular plate at a certain angle to detect the next pair of relatively set sector areas. Repeat the above process until the rectangular plate returns to the initial position and the detection is completed.

6. The method for locating and detecting excess matter inside an aircraft engine casing according to claim 4, characterized in that: According to the aircraft engine casing drawings, for areas with asymmetric structures, the detector collects signal detection steps as follows: rotate the rectangular plate at a certain angle to detect a pair of relatively set fan-shaped areas. If it is found that the number of reflections is more than the number of reflections known from the drawings, it means that there are excess objects; further count the time difference between the multiple reflections of each detector of the two detectors, and compare with the numerical distribution of the multiple reflection time difference inferred from the drawings to further determine the presence and location of excess objects.

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