Three-component micro-load balance calibration device and method

Abstract

The present application belongs to the field of dynamic measurement technology for aerospace force measurement tests, and discloses a three-component micro-load balance calibration device and method. The three-component micro-load balance calibration device includes a pulley, an air bearing, an exciter, a loading head, a calibration support rod, a six-degree-of-freedom adjustment mechanism, a laser positioning source, a nylon rope, a spherical loading point, etc. The six-degree-of-freedom adjustment mechanism is connected to the balance, and the balance is fixedly connected to the calibration support rod. One end of the calibration support rod is fixedly connected to the balance and the other end is connected to the loading head. The loading head is connected to the pulley through a nylon rope. An air bearing is provided inside the pulley, and an exciter is provided on the pulley seat. The laser positioning source is installed on the support to ensure that the laser displacement meter light source can be projected onto the loading head. The present application can realize the calibration of a micro-load balance with a range of less than 10mN, and solve the problems that the micro-load balance has a small range and cannot be loaded, and the calibration system itself has too large an uncertainty that affects the calibration result of the micro-load balance.

Description

Technical Field

[0001] The invention belongs to the technical field of dynamic measurement of aerospace force measurement tests, and specifically relates to a three-component micro-load balance calibration device and method. Background Art

[0002] Wind tunnel is the most basic experimental equipment for aerodynamic research and aircraft development. Force measuring wind tunnel test is the most basic test item in wind tunnel experiment, and wind tunnel balance is the most important measuring device in force measuring wind tunnel experiment, which is directly used to measure the size, direction and point of action of aerodynamic load acting on scaled models of aircraft, etc. After the wind tunnel balance completes the design, processing, strain gauge pasting, and Wheatstone bridge formation processes, it is necessary to use the balance calibration system to measure the relationship between the output voltage change of each component of the balance and the calibration load, that is, the wind tunnel balance formula. However, for the calibration of micro-load balances with a range of less than 10mN, the use of existing balance calibration technology will have disadvantages such as the balance range is too small to achieve loading, and the calibration system's own uncertainty is too large to affect the calibration results of the micro-load balance. Summary of the invention

[0003] In order to solve the problem that the range of a micro-load balance within 10mN is too small to achieve loading, and the uncertainty of the calibration system itself is too large to affect the calibration result of the micro-load balance, the present application provides a three-component micro-load balance calibration device and method.

[0004] Technical solution 1 adopted in this application:

[0005] A three-component micro-load balance calibration device, comprising a pulley, an air bearing, a shaft sleeve, a rotating shaft, a pulley seat, an exciter, a laser positioning source, a loading head, a spherical loading point, a nylon rope, a calibration support rod, a three-component micro-load balance, and a six-degree-of-freedom adjustment mechanism;

[0006] The upper end of the three-component micro-load balance is connected to the six-degree-of-freedom adjustment mechanism; the lower end of the three-component micro-load balance is fixedly connected to one end of the calibration support rod, and the other end of the calibration support rod is provided with a loading head; the pulley is arranged around the loading head, and the loading head and the pulley are connected through the nylon rope;

[0007] The pulley seat comprises a support arm and a base; the support arm of the pulley seat is vertically and integrally fixedly arranged on the base of the pulley seat; the lower end surface of the base of the pulley seat is fixedly connected to the support of the pulley seat;

[0008] The pulley is rotatably mounted on the pulley seat, the laser positioning source is mounted on the side wall of the pulley seat support, and the light source of the laser positioning source is projected onto the loading head.

[0009] Furthermore, the pulley is connected to the rotating shaft via an air bearing, the air bearing is encapsulated in the pulley via a sleeve, and both ends of the rotating shaft are connected to the support arms of the pulley seat.

[0010] Furthermore, the outer diameter of the pulley and the middle diameter of the air bearing have the following relationship:

[0011] ;

[0012] in, is the middle diameter of the air bearing, is the outer diameter of the pulley, is the friction coefficient of the air bearing, is the friction coefficient.

[0013] Furthermore, the loading head is designed to be a "sun"-shaped structure, and there are 6 spherical loading points, with two spherical loading points on each of the left and right sides of the "sun"-shaped structure, and one spherical loading point on each of the top and bottom; a center hole is opened in the spherical loading point, and the diameter of the center hole is consistent with the diameter of the nylon rope; the spherical loading point is connected to the pulley by a nylon rope.

[0014] Furthermore, a vibration exciter is arranged on the base support of the pulley seat.

[0015] Technical solution 2 adopted in this application:

[0016] A three-component micro-load balance calibration method is implemented using the three-component micro-load balance calibration device described in technical solution 1, and comprises the following steps:

[0017] Step 1: Install the loading head on the calibration support rod, install the calibration support rod on the three-component micro-load balance, connect the loading head, the calibration support rod and the three-component micro-load balance, and install the whole on the six-degree-of-freedom adjustment mechanism;

[0018] Step 2: Turn on the laser positioning source and adjust the six-degree-of-freedom adjustment mechanism to ensure that the feature point on the loading head coincides with the laser spot;

[0019] Step 3: Connect the nylon rope to the spherical loading point;

[0020] Step 4: Re-adjust the six-degree-of-freedom adjustment mechanism to ensure that the feature point and the laser spot are completely coincident, turn off the laser positioning source, and complete the initial positioning of the loading head;

[0021] Step 5. Calibrate the three-component micro-load balance according to the calibration loading table. After completing the loading of each weight, turn on the vibrator. The vibrator should work for no less than 5 seconds. After the vibrator stops vibrating, collect the balance output.

[0022] This application has the following beneficial effects:

[0023] 1. This application can realize the calibration of micro-load balances with a range of less than 10mN, solving the problems that the micro-load balance cannot be loaded due to a small range, and the calibration system's own uncertainty is too large to affect the calibration results of the micro-load balance.

[0024] 2. Install a vibration exciter on the pulley mounting seat to generate high-frequency vibration to further reduce the pulley friction. Through loading repeatability, it was found that the use of a vibration exciter can reduce the pulley friction by more than 40%;

[0025] 3. Initial positioning is performed through laser feature points to achieve initial positioning of the micro-load balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the front view of the three-component micro-load balance calibration device;

[0027] Figure 2 Install partial view for loading head;

[0028] Figure 3 A partial view of the pulley installation;

[0029] Figure 4 This is a diagram illustrating the relevant dimensions of the pulley;

[0030] Figure 5 This is a top view of the three-component micro-load balance calibration device.

[0031] In the figure: 1- pulley, 11- air bearing, 12- bushing, 13- rotating shaft, 14- pulley seat, 15- exciter, 2- laser positioning source, 3- loading head, 31- spherical loading point, 32- nylon rope, 4- calibration support rod, 5- three-component micro load balance, 6- six-degree-of-freedom adjustment mechanism. DETAILED DESCRIPTION

[0032] The present application will be described in detail below in conjunction with the accompanying drawings, but it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of the structure and technical common knowledge is omitted to avoid unnecessary confusion of the concept of the present application.

[0033] Embodiment 1: Combination Figure 1 To Attachment Figure 5 The present application discloses a three-component micro-load balance calibration device, comprising a pulley 1, an air bearing 11, a sleeve 12, a rotating shaft 13, a pulley seat 14, an exciter 15, a laser positioning source 2, a loading head 3, a spherical loading point 31, a nylon rope 32, a calibration support rod 4, a three-component micro-load balance 5, and a six-degree-of-freedom adjustment mechanism 6;

[0034] The upper end of the three - component micro - load balance 5 is connected to the six - degree - of - freedom adjustment mechanism 6; the lower end of the three - component micro - load balance 5 is fixedly connected to one end of the calibration support rod 4, and the other end of the calibration support rod 4 is provided with a loading head 3; the pulley 1 is arranged around the loading head 3, and the loading head 3 is connected to the pulley 1 through the nylon rope 32;

[0035] The pulley seat 14 includes a support arm and a base; the support arm of the pulley seat 14 is vertically and integrally fixed on the base of the pulley seat 14; the lower end face of the base of the pulley seat 14 is fixedly connected to the support of the pulley seat 14;

[0036] The pulley 1 is rotatably installed on the pulley seat 14, the laser positioning source 2 is installed on the side wall of the support of the pulley seat 14, and the light source of the laser positioning source 2 projects onto the loading head 3.

[0037] Further, the pulley 1 is connected to the rotating shaft 13 through an air - floating bearing 11, the air - floating bearing 11 is encapsulated in the pulley through a bushing 12, and both ends of the rotating shaft 13 are connected to the support arms of the pulley seat 14.

[0038] Further, the following relationship exists between the outer diameter of the pulley 1 and the mean diameter of the air - floating bearing 11:

[0039] ;

[0040] where, is the mean diameter of the air - floating bearing, is the outer diameter of the pulley, is the friction coefficient of the air - floating bearing, is the friction influence coefficient.

[0041] Further, the loading head 3 is designed in a "day" - shaped structure, there are 6 spherical loading points 31, two spherical loading points 31 are arranged on each of the left and right sides of the "day" - shaped structure, and one spherical loading point 31 is arranged on each of the upper and lower sides; a central hole is opened in the spherical loading point 31, and the diameter of the central hole is the same as the rope diameter of the nylon rope 32; the spherical loading point 31 is connected to the pulley 1 through the nylon rope 32.

[0042] Further, an exciter 15 is arranged on the support of the base of the pulley seat 14.

[0043] Embodiment 2: In combination with Figure 1~Figure 3 , the present application also provides a calibration method for a three - component micro - load balance, which is completed by using the three - component micro - load balance calibration device described in Embodiment 1, and includes the following steps:

[0044] Step 1: Install the loading head 3 on the calibration support rod 4, install the calibration support rod 4 on the three-component micro-load balance 5, and connect the loading head 3, the calibration support rod 4 and the three-component micro-load balance 5 and install them as a whole on the six-degree-of-freedom adjustment mechanism 6;

[0045] Step 2: Turn on the laser positioning source 2 and adjust the six-degree-of-freedom adjustment mechanism 6 to ensure that the characteristic point on the loading head 3 coincides with the laser spot;

[0046] Step 3, connecting the nylon rope 32 to the spherical loading point 31;

[0047] Step 4: Re-adjust the six-degree-of-freedom adjustment mechanism 6 to ensure that the feature point and the laser spot completely coincide with each other, turn off the laser positioning source, and complete the initial positioning of the loading head 3;

[0048] Step 5: Calibrate the three-component micro-load balance 5 according to the calibration loading table. After completing the loading of each weight, turn on the exciter 15. The exciter 15 works for no less than 5 seconds. The exciter 15 stops vibrating and then collects the balance output.

[0049] Working principle and process:

[0050] The present application performs initial positioning by aligning the characteristic points marked during the design and processing on the loading head with the laser light spot. Traditionally, the initial positioning of the loading head adopts mechanical initial positioning or a laser tracker for initial positioning. However, for the measurement of a small load balance with a range of less than 10mN, the mechanical initial positioning can easily cause the balance to be overloaded and damaged. When a laser tracker is used for initial positioning, the weight of the target ball will exceed the balance range and cause damage to the balance. The use of laser characteristic points will not cause the above problems. The laser positioning source is placed away from the loading head. The initial position of the loading head is adjusted so that the laser coincides with the characteristic points marked during the design and processing on the loading head, which means that the adjustment is in place.

[0051] In addition, in order to reduce the impact of the weight of the loading head on the balance, the loading head is designed into a "sun" shape structure. A spherical loading point is designed on the loading head. The nylon rope is connected to the loading head through the loading point, which not only plays a positioning role but also prevents the torque from being transmitted to the loading head.

[0052] The above embodiments are merely illustrative of the principles and effects of the present application, and are not intended to limit the present application. Anything within the technical concept disclosed in the present application, and any simple replacement or change based on the technical solution of the present application, shall fall within the protection scope of the present application.

Claims

1. A three-component micro-load balance calibration device, characterized in that: It includes a pulley (1), an air bearing (11), a bushing (12), a rotating shaft (13), a pulley seat (14), an exciter (15), a laser positioning source (2), a loading head (3), a spherical loading point (31), a nylon rope (32), a calibration support rod (4), a three-component micro-load balance (5), and a six-degree-of-freedom adjustment mechanism (6); The upper end of the three-component micro-load balance (5) is connected to the six-degree-of-freedom adjustment mechanism (6); the lower end of the three-component micro-load balance (5) is fixedly connected to one end of the calibration support rod (4), and the other end of the calibration support rod (4) is provided with a loading head (3); the pulley (1) is arranged around the loading head (3), and the loading head (3) is connected to the pulley (1) through the nylon rope (32); The pulley seat (14) includes a support arm and a base; the support arm of the pulley seat (14) is vertically and integrally fixed on the base of the pulley seat (14); the lower end face of the base of the pulley seat (14) is fixedly connected to the support of the pulley seat (14); The pulley (1) is rotatably installed on the pulley seat (14), and the laser positioning source (2) is installed on the side wall of the support of the pulley seat (14), and the light source of the laser positioning source (2) projects onto the loading head (3); The loading head (3) is designed in a "day" - shaped structure, and there are 6 spherical loading points (31). Two spherical loading points (31) are arranged on each of the left and right sides of the "day" - shaped structure, and one spherical loading point (31) is arranged on each of the upper and lower sides; a central hole is opened in the spherical loading point (31), and the diameter of the central hole is the same as the rope diameter of the nylon rope (32); the spherical loading point (31) is connected to the pulley (1) through the nylon rope (32).

2. The three-component micro-load balance calibration device according to claim 1, characterized in that: The pulley (1) is connected to the rotating shaft (13) through the air bearing (11), the air bearing (11) is encapsulated in the pulley through the bushing (12), and both ends of the rotating shaft (13) are connected to the support arms of the pulley seat (14).

3. The three-component micro-load balance calibration device according to claim 2, characterized in that: The following relationship exists between the outer diameter of the pulley (1) and the mid - diameter of the air bearing (11): ； in, is the middle diameter of the air bearing, is the outer diameter of the pulley, is the friction coefficient of the air bearing, is the friction coefficient.

4. The three-component micro-load balance calibration device according to claim 3, characterized in that: An exciter (15) is arranged on the support of the base of the pulley seat (14).

5. A three-component micro-load balance calibration method, characterized in that: It is completed by using the three - component micro - load balance calibration device described in claim 4, including the following steps: Step 1: Install the loading head (3) on the calibration support rod (4), install the calibration support rod (4) on the three - component micro - load balance (5), and after connecting the loading head (3), the calibration support rod (4) and the three - component micro - load balance (5), install them as a whole on the six - degree - of - freedom adjustment mechanism (6); Step 2: Turn on the laser positioning source (2), and by adjusting the six - degree - of - freedom adjustment mechanism (6), ensure that the characteristic point on the loading head (3) coincides with the laser light spot; Step 3: Connect the nylon rope (32) to the spherical loading point (31); Step 4: Readjust the six - degree - of - freedom adjustment mechanism (6) to ensure that the characteristic point coincides completely with the laser light spot, turn off the laser positioning source, and complete the initial positioning of the loading head (3). Step 5: Calibrate the three-component micro-load balance (5) according to the calibration loading table. After completing the loading of each weight, turn on the vibrator (15). The vibrator (15) works for no less than 5 seconds. The vibrator (15) stops vibrating and then collects the balance output.

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