Long range quasi-static six-axis force measurement device for spacecraft

Abstract

The application provides a wide-range quasi-static six-dimensional force measuring device for a spacecraft, comprising four force sensors, a set of upper and lower mounting plates, a charge amplifier and a data acquisition instrument, the four force sensors are installed between the upper mounting plate and the lower mounting plate and are distributed in a rectangular diagonal manner, the force sensors are connected with the charge amplifier, the charge amplifier outputs three-axis resultant force and resultant moment to the data acquisition instrument according to the measurement signals of the force sensors; the charge amplifier is a Kistler multi-channel signal conditioner, which is specifically used for calculating and outputting corresponding resultant force and resultant moment according to the measurement signals input by the force sensors. In this way, the application realizes wide-range wide-band quasi-static force measurement of the spacecraft, can obtain interface force and moment information at the connecting point of the spacecraft, has the advantages of wide test frequency band, high eccentricity test precision and low cost.

Description

Technical Field

[0001] This invention relates to the field of spacecraft force testing technology, and in particular to a large-range quasi-static six-dimensional force measurement device for spacecraft. Background Technology

[0002] Quasi-static loads generally refer to the combination of steady-state loads and low-frequency dynamic loads. The concept of quasi-static loads is often used when considering various loads comprehensively. In the aerospace field, rocket launches and spacecraft landings and takeoffs on other planets are typical quasi-static processes. Related ground-based verification force measurement tasks require broadband six-dimensional force measurement technology under thermal vacuum conditions.

[0003] Currently, based on their measurement methods, multidimensional force sensors can be classified into strain gauge, capacitive, inductive, photoelectric, and piezoelectric multidimensional force sensors. Among them, the working principle of a resistance strain gauge multidimensional force sensor is to output a signal of resistance change as the elastic deformation of the strain gauge. It features good static linearity, high accuracy, low hysteresis, and low stiffness, and is mostly used for static or low-frequency signal measurements. Inductive multidimensional force sensors mainly rely on electromagnetic induction theory, converting changes in the measured physical quantity into measurable inductance signal changes through a magnetic field. However, the relationship between sensitivity, linearity, and range of inductive force sensors is complex and difficult to coordinate, making them unsuitable for rapid dynamic measurements. Capacitive multidimensional force sensors can convert changes in mechanical quantity into measurable changes in capacitance to achieve the measurement purpose. They have advantages such as high sensitivity and strong overload capacity, but parasitic capacitance exists, which can easily affect measurement accuracy. Piezoelectric force sensors typically use quartz crystals, piezoelectric ceramics, etc., as force-sensitive elements, and work together with a measurement conversion circuit to complete the measurement of the measured quantity. They feature good dynamic performance, high accuracy, high sensitivity, good stability, and high natural frequency. Photoelectric force sensors mainly utilize photoelectric technology theory to convert changes in the measured quantity into corresponding electrical signals to detect the measured object. They feature fast response, high accuracy, and high sensitivity.

[0004] Piezoelectric triaxial force sensors are characterized by high accuracy, high stiffness, and a wide range of measurement and testing frequencies, making them suitable for triaxial force measurement in spacecraft. However, the structural design and manufacturing process of a six-dimensional force sensor significantly impact its measurement accuracy. Structural design directly affects sensor stiffness, dynamic and static measurement accuracy, sensitivity, and interdimensional coupling, making it a core factor determining sensor performance. Currently available six-dimensional force sensors, as mature products, do not meet the requirements for large-range, wide-frequency quasi-static six-dimensional force measurement in spacecraft ground tests in terms of range, accuracy, stiffness, and testing frequency range. Therefore, there is a need to develop a large-range, wide-frequency six-dimensional force measurement device suitable for spacecraft. Summary of the Invention

[0005] To address the aforementioned shortcomings, the present invention aims to provide a large-range quasi-static six-dimensional force measurement device for spacecraft, so as to meet the requirements for large-range broadband quasi-static six-dimensional force measurement in spacecraft ground tests.

[0006] To achieve the above objectives, the present invention provides a large-range quasi-static six-dimensional force measurement device for spacecraft, comprising four force sensors, a set of upper and lower mounting plates, a charge amplifier, and a data acquisition instrument. The four force sensors are mounted between the upper and lower mounting plates in a rectangular diagonal distribution. The force sensors are connected to the charge amplifier, which outputs the resultant force and resultant torque in three axes to the data acquisition instrument based on the measurement signals from the force sensors.

[0007] The charge amplifier is a Kistler multi-channel signal conditioner, specifically used for:

[0008] Based on the measurement signal input from the force sensor, the corresponding resultant force and resultant torque are calculated and output using the following formula:

[0009] F X =F X1＋2 +F X3+4 ;

[0010] F Y =F Y1+4 +F Y2+3 ;

[0011] F Z =F Z1 +F Z2 +F Z3 +F Z4 ;

[0012] M X =[b·(F Z1 +F Z2 -F Z3 -F Z4 )]·KM X ;

[0013] M Y =[a·(-F Z1 +F Z2 +F Z3 -F Z4 )]·KM Y ;

[0014] M Z =[b·(-F X1＋2 +F X3＋4 )+a·(F Y1+4 -F Y2＋3 )]·KM Z ;

[0015] Among them, F X F represents the resultant force along the X-axis of the four force sensors. Y F represents the resultant force along the Y-axis of the four force sensors. Z F represents the resultant force along the Z-axis of the four force sensors. X1+2 F represents the resultant force measured by the first force sensor and the second force sensor along the X-axis. X3+4 F represents the resultant force measured by the third and fourth force sensors along the X-axis. Y1+4 F represents the resultant force measured by the first and fourth force sensors along the Y-axis. Y2+3 F represents the resultant force measured by the second and third force sensors along the Y-axis. Z1 F represents the resultant force measured by the first force sensor along the Z-axis. Z2 F represents the resultant force measured by the second force sensor along the Z-axis. Z3 F represents the resultant force measured by the third force sensor along the Z-axis. Z4 M represents the resultant force measured by the fourth force sensor along the Z-axis. X M represents the resultant torque along the X-axis of the four force sensors. Y M represents the resultant torque along the Y-axis of the four force sensors. Z The resultant torque along the Z-axis of the four force sensors is represented by K, which represents the torque correction coefficient.

[0016] Optionally, the charge amplifier is also used for:

[0017] The resultant moment is calculated using the following formula, with the coordinate system of the measured flyover's center of mass as the reference:

[0018] L 器 =L 台 +ΔL;

[0019] M 器 =L 器 ×F;

[0020] M 台 =L 台 ×F;

[0021]

[0022] M x器 =M x台 +F z dy-F y dz;

[0023] M y器 =M y台 +F x dy-Fz dx;

[0024] M z器 =M z台 +F y dy-F x dy;

[0025] Among them, L 器 Let L be the center of mass of the leap vehicle. 台 Let M be the center of mass of the measuring device, F be the external force received by the leaping device, and M be the center of mass of the measuring device. 器 M represents the torque acting at the center of mass of the jump device, ΔL represents the change in the distance from the center of mass of the measuring device to the center of mass of the jump device, and M represents the torque acting at the center of mass of the jump device. x器 M is the resultant torque along the X-axis of the leap device after the center of mass transformation. y器 M is the resultant torque along the Y-axis of the leap device after the center of mass transformation. z器 M is the resultant torque along the Z-axis of the leap device after the center of mass transformation. x台 M is the resultant torque along the X-axis of the measuring device after the center of mass transformation. y台 M is the resultant torque along the Y-axis of the measuring device after the center of mass transformation. z台 This is the resultant torque along the Z-axis of the measuring device after the center of mass transformation.

[0026] Optionally, the force sensor is a commercially available piezoelectric large-range triaxial force sensor.

[0027] Optionally, the upper mounting plate and the lower mounting plate are rectangular symmetrical structures and are both made of aluminum.

[0028] Optionally, the data acquisition instrument is a multi-channel LMS system.

[0029] Optionally, the upper and lower end faces of the four force sensors are respectively connected and fixed to the upper mounting plate and the lower mounting plate, and the upper mounting plate and the lower mounting plate are assembled with the spacecraft under test.

[0030] Furthermore, the force sensor is fixed to the upper mounting plate and the lower mounting plate by screws.

[0031] The large-range quasi-static six-dimensional force measurement device for spacecraft described in this invention includes four force sensors, a set of upper and lower mounting plates, a charge amplifier, and a data acquisition instrument. The four force sensors are mounted between the upper and lower mounting plates in a rectangular diagonal distribution. Each force sensor is connected to the charge amplifier, which outputs the resultant force and resultant torque in three axes to the data acquisition instrument based on the measurement signals from the force sensors. The charge amplifier is a Kistler multi-channel signal conditioner, specifically used to calculate and output the corresponding resultant force and resultant torque based on the measurement signals input from the force sensors. Thus, this invention, based on a mature piezoelectric triaxial force sensor, achieves large-range, wide-bandwidth six-dimensional force measurement, possessing advantages such as wide test bandwidth, high eccentricity testing accuracy, and low cost, meeting the large-range, wide-bandwidth six-dimensional force measurement requirements of spacecraft. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the large-range quasi-static six-dimensional force measurement device for spacecraft provided in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the force sensor layout and resultant force direction of the large-range quasi-static six-dimensional force measurement device for spacecraft provided in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram showing the relative relationship between the large-range quasi-static six-dimensional force measurement device for spacecraft and the spacecraft coordinate system, as provided in an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0036] It should be noted that references to "an embodiment," "embodiment," "example embodiment," etc., in this specification refer to the described embodiment including specific features, structures, or characteristics, but not every embodiment must include these specific features, structures, or characteristics. Furthermore, such expressions do not refer to the same embodiment. Moreover, when describing specific features, structures, or characteristics in conjunction with embodiments, whether or not explicitly described, it is indicated that incorporating such features, structures, or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0037] Furthermore, certain terms are used in the specification and subsequent claims to refer to specific components or parts. Those skilled in the art will understand that manufacturers may use different names or terms to refer to the same component or part. This specification and subsequent claims do not distinguish components or parts by differences in name, but rather by differences in function. The terms "comprising" and "including" used throughout the specification and subsequent claims are open-ended and should be interpreted as "including but not limited to." Additionally, the term "connection" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connections made through other means.

[0038] Figure 1 This illustration shows a large-range quasi-static six-dimensional force measurement device for spacecraft provided by an embodiment of the present invention. It includes four force sensors, a set of upper and lower mounting plates, a charge amplifier, and a data acquisition instrument. Specifically, this embodiment includes a first force sensor 1, a second force sensor 2, a third force sensor 3, and a fourth force sensor 4; an upper mounting plate 5 and a lower mounting plate 6. The four force sensors are mounted between the upper mounting plate 5 and the lower mounting plate 6 in a rectangular diagonal distribution. The upper mounting plate 5 and the lower mounting plate 6 are vertically positioned. The first force sensor 1, the second force sensor 2, the third force sensor 3, and the fourth force sensor 4 are mounted in the area between the upper mounting plate 5 and the lower mounting plate 6, and the first force sensor 1, the second force sensor 2, the third force sensor 3, and the fourth force sensor 4 are arranged in a rectangular diagonal distribution. Figure 2 As shown; the force sensors are connected to the charge amplifier, that is, the first force sensor 1, the second force sensor 2, the third force sensor 3, and the fourth force sensor 4 are respectively connected to the charge amplifier to transmit the measured signals to the charge amplifier. The charge amplifier outputs the resultant force and resultant torque in three axes to the data acquisition instrument based on the measurement signals from the force sensors; wherein:

[0039] The charge amplifier is a Kistler multi-channel signal conditioner, specifically used for:

[0040] Based on the measurement signal input from the force sensor, the corresponding resultant force and resultant torque are calculated and output using the following formula:

[0041] F X =F X1+2 +F X3+4 ;

[0042] F Y =F Y1+4 +F Y2+3 ;

[0043] F Z =F Z1 +FZ2 +F Z3 +F Z4 ;

[0044] M X =[b·(F Z1 +F Z2 -F Z3 -F Z4 )]·KM X ;

[0045] M Y =[a·(-F Z1 +F Z2 +F Z3 -F Z4 )]·KM Y ;

[0046] M Z =[b·(-F X1+2 +F X3+4 )+a·(F Y1+4 -F Y2+3 )]·KM Z ;

[0047] Among them, F X F represents the resultant force along the X-axis of the four force sensors. Y F represents the resultant force along the Y-axis of the four force sensors. Z F represents the resultant force along the Z-axis of the four force sensors. X1+2 F represents the resultant force measured by the first force sensor and the second force sensor along the X-axis. X3+4 F represents the resultant force measured by the third and fourth force sensors along the X-axis. Y1+4 F represents the resultant force measured by the first and fourth force sensors along the Y-axis. Y2+3 F represents the resultant force measured by the second and third force sensors along the Y-axis. Z1 F represents the resultant force measured by the first force sensor along the Z-axis. Z2 F represents the resultant force measured by the second force sensor along the Z-axis. Z3 F represents the resultant force measured by the third force sensor along the Z-axis. Z4 M represents the resultant force measured by the fourth force sensor along the Z-axis. X M represents the resultant torque along the X-axis of the four force sensors. Y M represents the resultant torque along the Y-axis of the four force sensors. Z This represents the resultant torque along the Z-axis of the four force sensors, and K represents the torque correction coefficient.

[0048] The charge amplifier used in this embodiment is a Kistler 5080A multichannel charge amplifier with 8 input channels. It can output the resultant force and resultant torque in the X, Y, and Z directions. The quasi-static mode (DC_long) is selected during use. Its wiring method is shown in Table 1 below.

[0049] Table 1:

[0050]

[0051] Furthermore, since the resultant force and resultant torque obtained according to the above formula are based on the information of the center point of the measuring device, but the experiment focuses more on the resultant force and torque signals on the center of mass of the tested fly-off, according to the translation theorem, the resultant force is not affected by the change of the center of mass, but the resultant torque will change with the change of the center of mass. Therefore, this embodiment further calculates the center of mass transformation of the resultant torque using the coordinate system of the center of mass of the tested fly-off as a reference using the following formula:

[0052] L 器 =L 台 +ΔL;

[0053] M 器 =L 器 ×F;

[0054] M 台 =L 台 ×F;

[0055]

[0056]

[0057] M x器 =M x台 +F z dy-F y dz;

[0058] M y器 =M y台 +F x dy-F z dx;

[0059] M z器 =M z台 +F y dy-F x dy;

[0060] Among them, L 器 Let L be the center of mass of the leap vehicle. 台 Let M be the center of mass of the measuring device, F be the external force received by the leaping device, and M be the center of mass of the measuring device. 器 M represents the torque acting at the center of mass of the jump device, ΔL represents the change in the distance from the center of mass of the measuring device to the center of mass of the jump device, and M represents the torque acting at the center of mass of the jump device.x器 M is the resultant torque along the X-axis of the leap device after the center of mass transformation. y器 M is the resultant torque along the Y-axis of the leap device after the center of mass transformation. z器 M is the resultant torque along the Z-axis of the leap device after the center of mass transformation. x台 M is the resultant torque along the X-axis of the measuring device after the center of mass transformation. y台 M is the resultant torque along the Y-axis of the measuring device after the center of mass transformation. z台 This is the resultant torque along the Z-axis of the measuring device after the center of mass transformation.

[0061] Figure 3 The diagram illustrates the relative relationship between the measuring device and the coordinate system of the measured object. The force measuring platform in the diagram is the measuring device. In actual testing, it is necessary to determine the accurate resultant torque transformation formula based on the specific information of dx, dy, and dz obtained by the device, and use this formula to convert the resultant force and resultant torque information obtained by the measuring device into the resultant force and resultant torque information at the center of mass of the flyover.

[0062] In this embodiment, the force sensor is preferably a commercially available piezoelectric large-range triaxial force sensor. A suitable sensor can be selected based on the measurement requirements of the device being tested. For example, this embodiment uses a Kistler 9377C type triaxial piezoelectric charge sensor. Each force sensor has an adjustable longitudinal range of 8N to 300kN and an adjustable transverse range of 4N to 150kN. The sensor envelope is 120×120×125mm, and the fixing threaded holes are M16 with a hole spacing of 96mm. Therefore, through holes and countersunk holes are machined at corresponding positions on the upper and lower mounting plates to screw the sensor in place. The layout is as follows... Figure 2 As shown.

[0063] The upper mounting plate 5 and the lower mounting plate 6 are rectangular symmetrical structures and are both made of aluminum. In this embodiment, countersunk holes are machined at the four force sensor installation positions on the upper and lower mounting plates, and docking interfaces with spacecraft and fixed fixtures are reserved.

[0064] The upper and lower end faces of the four force sensors are respectively connected and fixed to the upper mounting plate 5 and the lower mounting plate 6, which are then assembled with the spacecraft under test. Furthermore, the force sensors are fixed to the upper mounting plate 5 and the lower mounting plate 6 by screw connections; specifically, high-strength bolts are used to connect the sensors to the mounting plates.

[0065] The force sensor signal is conditioned by a charge amplifier and then acquired by a data acquisition instrument; preferably, the data acquisition instrument is a multi-channel LMS system with a total of 32 acquisition channels, which meets the requirements of 6-channel input measurement.

[0066] Modal analysis of the measuring device described in this embodiment revealed that the fundamental frequency of the measuring device is 760Hz, which provides wideband testing capability and meets the test requirements. After the assembly of the measuring device is completed, it is calibrated to determine the torque correction coefficient.

[0067] In summary, the large-range quasi-static six-dimensional force measurement device for spacecraft described in this invention includes four force sensors, a set of upper and lower mounting plates, a charge amplifier, and a data acquisition instrument. The four force sensors are mounted between the upper and lower mounting plates in a rectangular diagonal distribution. The force sensors are connected to the charge amplifier, which outputs the resultant force and resultant torque in three axes to the data acquisition instrument based on the measurement signals from the force sensors. The charge amplifier is a Kistler multi-channel signal conditioner, specifically used to calculate and output the corresponding resultant force and resultant torque based on the measurement signals input from the force sensors. Thus, this invention, based on a mature piezoelectric triaxial force sensor, achieves large-range, wide-bandwidth six-dimensional force measurement, possessing advantages such as wide test bandwidth, high eccentricity testing accuracy, and low cost, meeting the large-range, wide-bandwidth six-dimensional force measurement requirements of spacecraft.

[0068] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A large-range quasi-static six-dimensional force measurement device for spacecraft, characterized in that, The system includes four force sensors, a set of upper and lower mounting plates, a charge amplifier, and a data acquisition unit. The four force sensors are mounted between the upper and lower mounting plates in a rectangular diagonal arrangement. Each force sensor is connected to the charge amplifier, which outputs the resultant force and resultant torque in three axes to the data acquisition unit based on the measurement signals from the force sensors. The charge amplifier is a Kistler multi-channel signal conditioner, specifically used for: Based on the measurement signal input from the force sensor, the corresponding resultant force and resultant torque are calculated and output using the following formula: F X =F X1+2 +F X3+4 ; F Y =F Y1+4 +F Y2+3 ; F Z =F Z1 +F Z2 +F Z3 +F Z4 ; M X =[b·(F Z1 +F Z2 -F Z3 -F Z4 )]·KM X ; M Y =[a·(-F Z1 +F Z2 +F Z3 -F Z4 )]·KM Y ; M Z =[b·(-F X1+2 +F X3+4 )+a·(F Y1+4 -F Y2+3 )]·KM Z ; Among them, F X F represents the resultant force along the X-axis of the four force sensors. Y F represents the resultant force along the Y-axis of the four force sensors. Z F represents the resultant force along the Z-axis of the four force sensors. X1+2 F represents the resultant force measured by the first force sensor and the second force sensor along the X-axis. X3+4 F represents the resultant force measured by the third and fourth force sensors along the X-axis. Y1+4 F represents the resultant force measured by the first and fourth force sensors along the Y-axis. Y2+3 F represents the resultant force measured by the second and third force sensors along the Y-axis. Z1 F represents the resultant force measured by the first force sensor along the Z-axis. Z2 F represents the resultant force measured by the second force sensor along the Z-axis. Z3 F represents the resultant force measured by the third force sensor along the Z-axis. Z4 M represents the resultant force measured by the fourth force sensor along the Z-axis. X M represents the resultant torque along the X-axis of the four force sensors. Y M represents the resultant torque along the Y-axis of the four force sensors. Z The resultant torque along the Z-axis of the four force sensors is represented by K, which represents the torque correction coefficient.

2. The large-range quasi-static six-dimensional force measurement device for spacecraft according to claim 1, characterized in that, The charge amplifier is also used for: The resultant moment is calculated using the following formula, with the coordinate system of the measured flyover's center of mass as the reference: L 器 =L 台 +ΔL; M 器 =L 器 ×F; M 台 =L 台 ×F; M x器 =M x台 +F Z of F y en: M y器 =M y台 +F x dy-F Z dx; M z器 =M z台 +F y of F x of; Among them, L 器 Let L be the center of mass of the leap vehicle. 台 Let M be the center of mass of the measuring device, F be the external force received by the leaping device, and M be the center of mass of the measuring device. 器 M represents the torque acting at the center of mass of the jump device, ΔL represents the change in the distance from the center of mass of the measuring device to the center of mass of the jump device, and M represents the torque acting at the center of mass of the jump device. x器 M is the resultant torque along the X-axis of the leap device after the center of mass transformation. y器 M is the resultant torque along the Y-axis of the leap device after the center of mass transformation. z器 M is the resultant torque along the Z-axis of the leap device after the center of mass transformation. x台 M is the resultant torque along the X-axis of the measuring device after the center of mass transformation. y台 M is the resultant torque along the Y-axis of the measuring device after the center of mass transformation. z台 This is the resultant torque along the Z-axis of the measuring device after the center of mass transformation.

3. The large-range quasi-static six-dimensional force measurement device for spacecraft according to claim 1, characterized in that, The force sensor is a commercially available piezoelectric large-range triaxial force sensor.

4. The large-range quasi-static six-dimensional force measurement device for spacecraft according to claim 1, characterized in that, The upper mounting plate and the lower mounting plate are rectangular symmetrical structures and are both made of aluminum.

5. The large-range quasi-static six-dimensional force measurement device for spacecraft according to claim 1, characterized in that, The data acquisition instrument is a multi-channel LMS system.

6. The large-range quasi-static six-dimensional force measurement device for spacecraft according to claim 1, characterized in that, The upper and lower end faces of the four force sensors are respectively connected and fixed to the upper mounting plate and the lower mounting plate, and the upper mounting plate and the lower mounting plate are assembled with the spacecraft under test.

7. The large-range quasi-static six-dimensional force measurement device for spacecraft according to claim 6, characterized in that, The force sensor is fixed to the upper mounting plate and the lower mounting plate by screws.

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