A capture device for testing mass in space gravitational wave detection

Abstract

A capture device for test mass in space gravitational wave detection, the present invention relates to a capture device for test mass, in order to meet the requirements of low disturbance release of test mass, the present invention comprises a capture plunger, a hollow shaft ultrasonic motor, a lead screw nut assembly, a strain amplification structure, an end cover and a base, the lead screw nut assembly is installed in the middle of the base, the strain amplification structure and the upper end of the lead screw nut assembly, the lower end of the capture plunger passes through the strain amplification structure and the lead screw nut assembly in sequence and is inserted into the hollow shaft ultrasonic motor, the upper end of the capture plunger is embedded in the card slot of the strain amplification structure, and the end cover is fixedly connected to the upper surface of the strain amplification structure. The present invention has the advantages of simple structure, reliable performance, small space occupation and reusability, ensuring the accuracy and stability of the test mass capture process. The present invention belongs to the field of aerospace technology.

Description

Technical Field

[0001] The invention relates to a capture device for testing mass, in particular to a capture device for testing mass used in space gravitational wave detection. The invention belongs to the field of aerospace technology. Background Art

[0002] Gravitational waves are matter waves that transmit energy in the form of gravitational radiation. Their proposal has proposed a new means for detecting nature. On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory in the United States observed a transient gravitational wave signal generated by the merger of black holes. This is the first time that humans have directly detected gravitational waves. However, the measurement range of land-based gravitational wave detection is narrow and easily interfered. Therefore, it is of great significance to build a laser interferometer gravitational wave detection device in space.

[0003] The light source of the space gravitational wave detection device emits laser, which is received by the receiver after being reflected by the surface of the test mass. When a gravitational wave passes through the light path, it will cause changes in the light, and then produce light interference. The gravitational waves are detected by the changes in the received information. Gravitational waves have the characteristics of low frequency, small amplitude, and are not easy to monitor, which puts strict requirements on the accuracy of the entire system. Among them, the test mass is the core component of the space gravitational wave detection device. Ensuring its low disturbance release is of great significance to improving the accuracy of the entire detection system.

[0004] After the satellite is stabilized in orbit, in order to meet the requirements of low-disturbance release of the test mass, it is necessary to design a mechanism to capture the test mass between the locking process and the release process, so as to gradually reduce the locking force and reduce the contact area between the mechanism and the test mass. Summary of the invention

[0005] In order to meet the requirement of low-disturbance release of the test mass, the present invention needs to design a mechanism to capture the test mass between the locking process and the releasing process, so as to reduce the locking force in stages and reduce the contact area between the mechanism and the test mass, thereby proposing a capture device for the test mass in space gravitational wave detection.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] The present invention includes a capture plunger, a hollow shaft ultrasonic motor, a screw nut assembly, a strain amplification structure, an end cover and a base. The screw nut assembly is installed in the middle part of the base, the strain amplification structure and the upper end of the screw nut assembly, the lower end of the capture plunger passes through the strain amplification structure and the screw nut assembly in sequence and is then inserted into the hollow shaft ultrasonic motor, the upper end of the capture plunger is embedded in the card slot of the strain amplification structure, and the end cover is fixedly connected to the upper surface of the strain amplification structure.

[0008] Furthermore, the screw nut assembly includes a split nut, a rolling bearing and a screw sleeve. The screw sleeve is inserted in the middle of the base. The screw sleeve is connected to the split nut by a thread. The split nut is connected to the inner wall of the base through the rolling bearing. The bearing end cover is located on the upper part of the rolling bearing and is fixedly connected to the upper end of the base. The output shaft of the hollow shaft ultrasonic motor is fixedly connected to the nut.

[0009] Furthermore, a disc spring is provided between the bearing end cover and the base, and the lower end of the screw passes through the bearing end cover and the disc spring and is connected to the upper end of the base.

[0010] Furthermore, a force sensor is provided on the upper surface of the strain amplification structure.

[0011] Furthermore, arched holes are provided on both sides of the lower surface of the strain amplification structure.

[0012] Furthermore, a displacement sensor is respectively provided on both sides of the upper surface of the base.

[0013] Furthermore, the outer contour of the lower end of the capture plunger gradually decreases from top to bottom.

[0014] Furthermore, the capture device for testing mass in space gravitational wave detection also includes a plunger locking mechanism, which includes a locking block, an adjusting screw and a large disc. The large disc is mounted on the outside of the end cover, and a guide groove is provided on the upper surface of the large disc. The locking block is installed in the guide groove of the large disc, and the adjusting screw is inserted from both sides of the large disc and tightens the locking block.

[0015] Furthermore, an upper surface of the end cover is provided with an inclined surface.

[0016] Furthermore, the lower surface of the locking block is provided with an inclined surface that matches the inclined surface of the upper surface of the end cover.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention forms a screw nut match by means of a split nut and a screw sleeve, which has good self-locking properties, so that the capture plunger is reliably locked in the axial and radial directions. At the same time, the screw nut has the advantages of easy control and simple structure. The use of this driving scheme can reduce the difficulty of mechanism control while reducing the corresponding manufacturing cost;

[0019] 2. The present invention arranges a disc spring between the bearing end cover and the base, and adjusts the compression amount of the disc spring by means of a screw, thereby adjusting the preload force applied by the bearing end cover to the split nut and the rolling bearing. The existence of the preload force eliminates the axial clearance of the capture mechanism when it is working (the axial clearance of the bearing and the axial clearance when the screw nut is matched), thereby ensuring the high precision of the mechanism, and reducing the return difference of the mechanism to a certain extent, so as to facilitate the subsequent motion control thereof;

[0020] 3. Since there are large vibrations and impacts during the launch phase, which affect the motion accuracy of the capture mechanism, the present invention provides a plunger locking mechanism based on the capture structure, and the locking block locks the capture mechanism below by adjusting the positions of the adjustment screws at both ends;

[0021] 4. The present invention uses an ultrasonic motor as a power source and is driven by friction, which will not cause magnetic field interference to the inertial sensor. At the same time, it will not generate magnetic torque inside the test mass to affect the stability of the test mass.

[0022] 5. The present invention inserts the capture plunger into the hollow shaft ultrasonic motor, and the hollow hole of the motor plays a good guiding role, which can prevent the huge vibration generated during the launch process from causing the plunger position to shift, thereby ensuring the position accuracy;

[0023] 6. The present invention has the advantages of simple structure, reliable performance, small space occupation and reusability, ensuring the accuracy and stability of the test quality capture process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view of the overall structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the overall appearance of the present invention;

[0026] Figure 3 It is a structural schematic diagram of the plunger locking mechanism of the present invention. DETAILED DESCRIPTION

[0027] Specific implementation method 1: Combination Figure 1The present embodiment is described. The capture device described in the present embodiment includes a capture plunger 1-1, a hollow shaft ultrasonic motor 1-2, a split nut 1-3, a rolling bearing 1-4, a disc spring 1-5, a bearing end cover 1-6, a screw sleeve 1-7, a strain amplification structure 1-8, an end cover 1-9 and a base 1-10. The screw sleeve 1-7 is inserted in the middle of the base 1-10. The screw sleeve 1-7 is connected to the split nut 1-3 by threads. The split nut 1-3 is embedded together by an upper and a lower nut. The upper and the lower nuts are connected to the inner wall of the base 1-10 through a rolling bearing 1-4 respectively; the hollow shaft The ultrasonic motor 1-2 is installed at the lower part of the base 1-10, and its output shaft is fixedly connected to the nut 1-3. The strain amplification structure 1-8 is installed at the upper end of the screw sleeve 1-7. The lower end of the capture plunger 1-1 passes through the strain amplification structure 1-8 and the screw sleeve 1-7 in sequence and is inserted into the hollow shaft ultrasonic motor 1-2. The upper end of the capture plunger 1-1 is embedded in the slot of the strain amplification structure 1-8. The end cover 1-9 is fixedly connected to the upper surface of the strain amplification structure 1-8. The bearing end cover 1-6 is fixedly connected to the upper end of the base 1-10, and a disc spring 1-5 is provided between the bearing end cover 1-6 and the base 1-10.

[0028] The contact part between the capture plunger 1-1 and the test mass is designed to realize the six-degree-of-freedom positioning of the test mass; the hollow shaft ultrasonic motor 1-2 greatly improves the compactness of the structure, and at the same time eliminates the coupling and other components, reduces the complexity of the mechanism, and improves its working efficiency and reliability; the split nut 1-3 and the screw sleeve 1-7 form a screw nut match, which has good self-locking property, so that the capture plunger 1-1 is reliably locked in the axial and radial directions, and the screw nut has the advantages of easy control and simple structure. The use of this drive scheme can reduce the difficulty of mechanism control while reducing the corresponding manufacturing cost; a disc spring 1-5 is arranged between the bearing end cover 1-6 and the base 1-10. The compression amount of the disc spring 1-5 is adjusted by the screw, and then the preload force applied by the bearing end cover 1-6 to the split nut 1-3 and the rolling bearing 1-4 is adjusted. The existence of the preload force eliminates the axial clearance of the capture mechanism when it is working, the axial clearance of the bearing, and the axial clearance when the screw nut is matched, ensuring the high precision of the mechanism, and at the same time reducing the return difference of the mechanism to a certain extent, which is convenient for subsequent motion control.

[0029] Advantages of using split nut 1-3: For ordinary screw nut structure, due to problems such as processing accuracy, there will be a certain gap between the screw thread and the nut thread after the two are matched, which will cause a large axial gap during the screw nut transmission, resulting in a certain return difference, affecting the accuracy of the transmission. Therefore, it is proposed to divide the nut into upper and lower parts to make a split type. The upper and lower nuts are guaranteed to have the consistency of their rotation through the D-shaped hole, and then the two are pressed on the screw through the bearing end cover 1-6 and the clamping disc spring 1-5 on them. The split nut 1-3 can be well pressed on the thread of the screw sleeve 1-7, thereby eliminating its axial gap and improving the accuracy of the movement. At the same time, the bearing end cover 1-6 is used to apply a preload force to eliminate the axial gap of the bearing used for the support nut, which greatly improves the axial movement accuracy of the mechanism. Because of the existence of the preload force, the axial clearance of the capture mechanism when it is working (the axial clearance of the bearing and the axial clearance when the screw nut is matched) is eliminated, thereby ensuring the high-precision operation of the capture mechanism when it is working. At the same time, it reduces the return difference of the mechanism to a certain extent, which facilitates the subsequent motion control of the capture mechanism.

[0030] Its working method is: when the mechanism is installed and adjusted, the compression amount of the disc spring 1-5 is adjusted by the screw to adjust the preload force applied by the bearing end cover 1-6 on the split nut 1-3 and the rolling bearing 1-4. At the same time, in order to ensure that the preload force at both ends of the bearing end cover 1-6 is consistent, the screws on both sides should be adjusted at the same time, and the preload force of the bearing end cover 1-6 pressed on the upper end of the screw nut should be measured and adjusted repeatedly to finally ensure the accuracy of the preload force.

[0031] Preferably, the upper surface of the end cover 1 - 9 is provided with an inclined surface.

[0032] Preferably, the outer contour of the lower end of the capture plunger 1 - 1 gradually decreases from top to bottom.

[0033] Specific implementation method 2: Combination Figure 2 This embodiment is described. In this embodiment, a force sensor 3 is provided on the upper surface of the strain amplification structure 1-8. A displacement sensor 4 is provided on both sides of the upper surface of the base 1-10.

[0034] The force sensor 3 is composed of four strain gauges connected in a Wheatstone bridge manner, and its measurement results are accurate and stable. The pressure generated by the capture plunger 1-1 contacting the test mass will be transmitted along the capture plunger 1-1 to the upper strain amplification structure 1-8, causing it to deform, and the strain gauge on the force sensor will also deform, and the capture force will be measured.

[0035] Preferably, arched holes 1-8-1 are provided on both sides of the lower surface of the strain amplification structure 1-8. The arched holes 1-8-1 correspond to the positions of the strain gauges. The strain amplification structure is designed to be arched, which can amplify the deformation amount and facilitate the sensor to measure the contact force between the capture plunger and the test mass.

[0036] The displacement sensor 4 is a cantilever beam displacement sensor. When the capture mechanism 1 just contacts the test mass, the stopper also just contacts the displacement sensor, and the strain gauge reaches the limit position of deformation, thereby realizing the measurement of displacement. In order to ensure the measurement accuracy, the force sensor 3 and the displacement sensor 4 used in the present invention both have extremely high measurement resolution.

[0037] Specific implementation method three: Combination Figure 3 This embodiment is described. A capture device for testing mass in space gravitational wave detection described in this embodiment also includes a plunger locking mechanism 2, which includes a locking block 2-1, an adjusting screw 2-2 and a large disc 2-3. The large disc 2-3 is sleeved on the outside of the end cover 1-9. The upper surface of the large disc 2-3 is provided with a guide groove. The locking block 2-1 is installed in the guide groove of the large disc 2-3. The adjusting screw 2-2 is inserted from both sides of the large disc and tightens the locking block 2-1. The lower surface of the locking block 2-1 is provided with an inclined surface that matches the inclined surface of the upper surface of the end cover 1-9.

[0038] Since there are large vibrations and impacts during the launch phase, which affect the movement accuracy of the capture mechanism, the present invention sets a plunger locking mechanism 2 based on the capture mechanism 1. During the ground installation phase, the locking block 2-1 is locked to the capture mechanism 1 below by adjusting the positions of the adjustment screws 2-2 at both ends.

[0039] Working process of locking block:

[0040] After the locking mechanism completes the locking of the test mass, since the capture plunger 1-1 in the secondary mechanism is sleeved in the screw sleeve 1-7, if it is not locked during the launch phase, it will cause a large vibration and affect the movement accuracy of the capture mechanism later. Therefore, a plunger locking mechanism 2 is set, and during assembly, the locking block 2-1 is restricted by the screw sleeve 1-7 in the guide groove of the large disc 2-3, and the adjusting screw 2-2 is installed from both sides of the large disc 2-3 and supports the locking block 2-1.

[0041] During ground assembly, after the locking mechanism is locked and tested for quality, its large disc 2-3 is lowered to the lowest position. At this time, the adjusting screws 2-2 on both sides of the disc are adjusted to make the locking block 2-1 move left and right, so that the inclined surface of the locking block is pressed against the inclined surface of the upper end cover 1-9 of the plunger to complete the locking of the plunger during the launch phase. After being stable on the track, the locking block 2-1 retreats with the large disc 2-3 and separates from the captured plunger 1-1 to complete the release of the plunger.

[0042] Working principle:

[0043] 1. Install each component:

[0044] First, the plunger screw sleeve 1-7 is connected to the strain amplification structure 1-8 with the force sensor attached thereto through four screws on both sides, and then the capture plunger 1-1 is installed into the screw sleeve 1-7. The upper end of the capture plunger 1-1 is supported by the slot of the strain amplification structure 1-8, and the adjustable end cover 1-9 is connected to the strain amplification structure 1-8 using screws. By adjusting the pre-tightening force of the screws, the strain amplification structure 1-8, the plunger screw sleeve 1-7 and the capture plunger 1-1 are pressed against each other.

[0045] Then, the split nut 1-3 is connected to the plunger screw sleeve 1-7 through threads, and the split nut 1-3 is installed in the base 1-10 through the rolling bearing 1-4; the bearing end cover 1-6 and the base 1-10 are pressed together by screws and disc springs 1-5; then the hollow shaft ultrasonic motor 1-2 is connected to the split nut 1-3 from below the base 1-10, and the capture plunger 1-1 is inserted into the hollow shaft ultrasonic motor 1-2; the hollow shaft ultrasonic motor 1-2 is installed on the base 1-10, and the installation process of the capture mechanism 1 is completed.

[0046] Finally, install the locking block 2-1 into the guide groove of the large disk 2-3, install the adjusting screws 2-2 from both sides of the large disk 2-3 and support the locking block 2-1, lower the large disk 2-3 to the lowest position, adjust the pre-tightening force of the adjusting screws 2-2, so that the inclined surface of the locking block 2-1 and the inclined surface of the adjustable end cover 1-9 are pressed against each other, and the installation process of the plunger locking mechanism 2 is completed.

[0047] 2. Working process:

[0048] When the satellite is stable in orbit, the hollow shaft ultrasonic motor 1-2 starts to work, and the output shaft of the motor is directly connected to the split nut 1-3, and the drive nut 1-3 drives the screw sleeve 1-7 to move, forming a screw nut transmission; since the screw sleeve 1-7 and the strain amplification mechanism 1-8 are connected by screws, and the capture plunger 1-1 is embedded in the card slot of the strain amplification mechanism 1-1, the screw sleeve 1-7 will drive the strain amplification mechanism 1-8 and the capture plunger 1-1 to move in the direction of the test mass until the lower end of the capture plunger 1-1 contacts the test mass. At this time, the contact force between the capture plunger 1-1 and the test mass will be transmitted to the upper strain amplification structure 1-8 and cause it to deform, and the force sensor thereon will produce a change in the indication. When the 1N capture force is reached, the hollow shaft ultrasonic motor 1-2 stops working and completes the capture of the test mass. The capture device of the present invention can realize fine adjustment of the test mass position, so that the test mass and the electrode frame are strictly aligned; realize 6-degree-of-freedom positioning of the test mass to ensure that the test mass does not rotate.

[0049] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A capture device for testing mass in space gravitational wave detection, characterized in that: The capture device comprises a capture plunger (1-1), a hollow shaft ultrasonic motor (1-2), a lead screw nut assembly, a strain amplification structure (1-8), an end cover (1-9) and a base (1-10); the lead screw nut assembly is mounted in the middle of the base (1-10); the strain amplification structure (1-8) is mounted on the upper end of the lead screw nut assembly; the lower end of the capture plunger (1-1) passes through the strain amplification structure (1-8) and the lead screw nut assembly in sequence and is then inserted into the hollow shaft ultrasonic motor (1-2); the upper end of the capture plunger (1-1) is embedded in a slot of the strain amplification structure (1-8); and the end cover (1-9) is fixedly connected to the upper surface of the strain amplification structure (1-8); The screw nut assembly comprises a split nut (1-3), a rolling bearing (1-4) and a screw sleeve (1-7); the screw sleeve (1-7) is inserted in the middle of a base (1-10); the screw sleeve (1-7) is connected to the split nut (1-3) via a thread; the split nut (1-3) is connected to the inner wall of the base (1-10) via the rolling bearing (1-4); the bearing end cover (1-6) is located on the upper part of the rolling bearing 1-4 and is fixedly connected to the upper end of the base (1-10); and the output shaft of the hollow shaft ultrasonic motor (1-2) is fixedly connected to the split nut (1-3).

2. A capture device for testing mass in space gravitational wave detection according to claim 1, characterized in that: A disc spring (1-5) is provided between the bearing end cover (1-6) and the base (1-10), and the lower end of the screw passes through the bearing end cover (1-6) and the disc spring (1-5) and is connected to the upper end of the base (1-10).

3. The capture device for testing mass in space gravitational wave detection according to claim 1, characterized in that: A force sensor (3) is provided on the upper surface of the strain amplification structure (1-8).

4. A capture device for testing mass in space gravitational wave detection according to claim 1 or 3, characterized in that: Arched holes (1-8-1) are provided on both sides of the lower surface of the strain amplification structure (1-8).

5. The capture device for testing mass in space gravitational wave detection according to claim 1, characterized in that: A displacement sensor (4) is respectively provided on both sides of the upper surface of the base (1-10).

6. The capture device for testing mass in space gravitational wave detection according to claim 1, characterized in that: The outer contour of the lower end of the capture plunger (1-1) gradually decreases from top to bottom.

7. The capture device for testing mass in space gravitational wave detection according to claim 1, characterized in that: The capture device for testing mass in space gravitational wave detection further comprises a plunger locking mechanism (2), the plunger locking mechanism (2) comprising a locking block (2-1), an adjusting screw (2-2) and a large disc (2-3), the large disc (2-3) being sleeved on the outside of an end cover (1-9), a guide groove being provided on the upper surface of the large disc (2-3), the locking block (2-1) being installed in the guide groove of the large disc (2-3), the lower surface of the locking block (2-1) being located on the upper surface of the end cover (1-9), and the adjusting screw (2-2) being inserted from both sides of the large disc and tightening the locking block (2-1).

8. The capture device for testing mass in space gravitational wave detection according to claim 7, characterized in that: An inclined surface is provided on one side of the upper surface of the end cover (1-9).

9. The capture device for testing mass in space gravitational wave detection according to claim 7, characterized in that: The lower surface of the locking block (2-1) is provided with an inclined surface that matches the inclined surface of the upper surface of the end cover (1-9).

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