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CN-116337305-B - Low-interference differential device and method for micro-thrust measurement

CN116337305BCN 116337305 BCN116337305 BCN 116337305BCN-116337305-B

Abstract

The invention discloses a low-interference differential device and a method for micro-thrust measurement. The measuring device comprises a vibration isolation table, a propeller, a long beam support, two cantilever beams with the same specification, a strain gauge, an impact hammer, an acceleration sensor, an embedded main control chip and an upper computer, wherein the propeller is used for generating standard force, the long beam support is fixed on the vibration isolation table, the cantilever beams with the same specification are fixed on the cross beam support through a clamp, the strain gauge is stuck to the tail end of the cantilever beam and used for measuring bending strain of the beam, the impact hammer and the acceleration sensor are fixed on the impact hammer, the embedded main control chip is used for collecting data of the strain gauge and the acceleration sensor, and the upper computer is responsible for communicating with the main control chip and performing thrust calculation. The double-beam differential measuring device designed by the invention has the advantages of improving the common mode rejection ratio of the system, reducing the influence of environmental temperature, vibration and other common mode noise on the measurement stability and the like.

Inventors

  • ZHAO LIYE
  • HUANG XUAN
  • XU JIAWEN
  • CHEN XINGYU
  • LI ZHENGYU

Assignees

  • 东南大学

Dates

Publication Date
20260505
Application Date
20230423

Claims (6)

  1. 1. A low-interference differential device for micro-thrust measurement is characterized by comprising a vibration isolation table (1), a propeller (2), a beam support (3), a cantilever beam (4), an impact hammer (7), a main control chip (9) and an upper computer (10), wherein the beam support (3) is fixed on the vibration isolation table (1), two cantilever beams (4) with the same specification are fixed on the beam support (3) through a clamp (5), a strain gauge (6) is adhered to the tail end of the cantilever beam, the propeller (2) is aligned to the middle part of the front end of one cantilever beam, the impact hammer (7) is aligned to the middle part of the front end of the two cantilever beams (4), an acceleration sensor (8) is fixed on the impact hammer (7), and data of the strain gauge () and the acceleration sensor (8) are transmitted to the upper computer (10) through the main control chip (9).
  2. 2. A low interference differential device for micro-thrust measurement according to claim 1, wherein the cantilever beam (4) is a 65Mn quenched spring steel sheet.
  3. 3. A low interference differential device for micro-thrust measurement according to claim 2, wherein the cantilever beam (4) has a thickness of 0.3mm, a width of 40mm and a length of 240mm, and the point of action of the impact hammer (7) and the propeller (2) is 1cm in front of the cantilever beam.
  4. 4. A low-interference differential device for micro-thrust measurement according to claim 1, characterized in that the impact force hammer (7) is on the same point as the point of action of the propeller (2).
  5. 5. A low-interference differential device for measuring micro-thrust is characterized by comprising the following steps of carrying out differential thrust measurement by using two cantilever beams with the same specification as a comparison, firstly using a propeller to generate standard static force to act on one cantilever beam, generating bending response at the fixed end of the cantilever beam, carrying out instantaneous recording response output through a strain gauge, carrying out communication through a main control chip and collecting the obtained response output on an upper computer, calibrating a linear relation between displacement and response, secondly, knocking one cantilever beam by using an impact hammer, recording acceleration excitation by using an acceleration sensor, generating bending strain of the strain gauge as response output, respectively establishing mathematical models of the two cantilever beams according to system identification, obtaining an inverse system state space equation, then using the propeller to apply standard thrust to act on one cantilever beam, and then using the other cantilever beam to not apply thrust, respectively recording the response of the strain gauge, pushing out a thrust input signal through an inverse system, and carrying out differential solution to obtain the thrust.
  6. 6. A thrust measuring method based on the low interference differential device for micro thrust measurement as claimed in claim 1, characterized in that: Applying impulse response delta (t) to the bottom end point of the cantilever beam at one side by the impact force hammer, generating bending strain x 1 (t) at the fixed end, obtaining the Laplace transformation of unit impulse force to be 1, obtaining the system response under unit impulse, obtaining the transfer function of a measuring system by performing Laplace transformation, and establishing a mathematical model for the measuring system by identification, wherein the preset identified system order is 2, the excitation signal is an acceleration sensor output signal, and the response signal is a bending strain gauge displacement signal; Respectively identifying two cantilever beams to obtain two groups of intrinsic damping of modal parameters Modal damping Modal vector Modal matrix The state equation of the cantilever beam measuring system is obtained as follows Wherein, the In order to input the vector(s), In order to output the vector quantity, The system is stable, reversible, controllable and observable, and the inverse system state space equation is When the thrust is measured, the propeller applies the thrust f (t) at the midpoint of the bottom end of the left cantilever beam, the right cantilever beam does not apply any excitation, the responses y 1 (t) and y 2 (t) of the two bending strain gauges are obtained, the input responses U 1 (t) and U 2 (t) are respectively obtained according to the state space equation of the inversion system, and the magnitude of the thrust applied by the propeller can be obtained by differentiating the input responses U 1 (t) and the input responses U 2 (t).

Description

Low-interference differential device and method for micro-thrust measurement Technical Field The invention belongs to the technical field of micro-thrust measurement, and particularly relates to a low-interference differential device and method for micro-thrust measurement. Background The precise thrust measurement has important application in the fields of satellite position control, gravitational wave detection and the like, and has become a key problem for restricting the development of thrust technology. The satellite-borne micro-propeller is a foundation for realizing accurate attitude control, orbit control and rapid maneuvering of the micro-nano satellite. At present, the research of micro-propulsion technology required by the tasks is actively carried out at home and abroad, and mainly comprises cold air micro-propulsion technology, radio frequency ion micro-propulsion technology, field emission electric propulsion technology, colloid ion micro-propulsion technology, split-field micro-propulsion technology and other novel micro-propulsion technologies. The thrust generated by the micro propulsion technology is generally from a few micro-newtons to hundred micro-newtons, the resolution requirement reaches the sub-micro-newtons, so that a new challenge is provided for the thrust measurement of the micro-thruster, a great amount of thrust measurement research has been carried out at home and abroad, but the heavy load and the precision are still difficult to balance, the instability of the environment temperature, the installation measurement error and the uncertainty of the mechanical structure also have significant influence on the thrust measurement of the thrust device, and a certain difficulty is brought to the measurement of the micro-thrust. Disclosure of Invention In order to solve the problems, the invention discloses a low-interference differential device and a method for micro-thrust measurement, which select a high-precision and high-resolution bending strain gauge as a sensing device of cantilever beam vibration displacement, use a combination of an impact hammer and an acceleration sensor as an excitation generating device, use a differential double beam as a response device, use a propeller to generate standard force to be applied on a single beam, control data reading of the strain gauge and the acceleration sensor by a singlechip main control chip, and carry out data processing and thrust calculation by an upper computer, wherein the differential double beam can effectively inhibit external interference and accurately measure the thrust. In order to achieve the above purpose, the technical scheme of the invention is as follows: A low-interference differential device for micro-thrust measurement comprises a vibration isolation table, a propeller, a beam support, cantilever beams, impact force hammers, a main control chip and an upper computer, wherein the beam support is fixed on the vibration isolation table, two cantilever beams with the same specification are fixed on the beam support through clamps, strain gages are stuck to the tail ends of the cantilever beams, the propeller is aligned to the middle part of the front end of one cantilever beam, the impact force hammers are aligned to the middle parts of the front ends of the two cantilever beams, acceleration sensors are fixed on the impact force hammers, and data of the strain gages and the acceleration sensors are transmitted to the upper computer through the main control chip. As an improvement of the invention, the cantilever beam is a 65Mn quenched spring steel sheet. As an improvement of the invention, the thickness of the cantilever beam is 0.3mm, the width is 40mm, the length is 240mm, and the action point of the impact force hammer and the propeller is 1cm at the front end of the cantilever beam. As an improvement of the invention, the impact force hammer and the action point of the propeller are on the same point. The invention relates to a propeller which is used for generating standard force, a cross beam bracket, two cantilever beams with the same specification, a strain gauge, an impact hammer, an acceleration sensor, an embedded main control chip and an upper computer, wherein the cross beam bracket is fixed on a vibration isolation table, the two cantilever beams with the same specification are fixed on the cross beam bracket through a clamp, the strain gauge is stuck at the tail end of the cantilever beam and used for measuring bending strain of the beam, the impact hammer and the acceleration sensor are fixed on the impact hammer, the embedded main control chip is used for collecting data of the strain gauge and the acceleration sensor, and the upper computer is responsible for communicating with the main control chip and performing thrust calculation. The invention adopts the working principle that two cantilever beams with the same specification are used as a contrast to carry out differential thrust measuremen