System and method for measuring weight and gravity center of unmanned helicopter

Abstract

The invention discloses a system and a method for measuring the weight center of gravity of an unmanned helicopter, belongs to the technical field of unmanned aerial vehicles, and is used for solving the problems of low measurement precision and limited measurement scene of the system for measuring the weight center of gravity of the unmanned helicopter. The measuring system comprises a weight measuring unit, a horizontal measuring unit, a lifting unit and a distance measuring unit. The weight measuring unit comprises four weight measuring assemblies; the horizontal measuring unit comprises a first bevel protractor and a second bevel protractor, the first bevel protractor and the second bevel protractor are located on a main shaft of the unmanned helicopter, the distance measuring unit comprises a horizontal laser instrument and a laser centering tool, the laser centering tool is fixed on the main shaft of the unmanned helicopter, and the laser centering tool comprises an inclined laser centering line. The center line of the laser pair and the center line of the spindle are coplanar. According to the measuring system and the measuring method, the position of the weight gravity center of the unmanned helicopter measured by a four-point weighing method in the horizontal direction can be improved, and testing of different helicopter types and different sites can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of unmanned aerial vehicles, and relates to a system and method for measuring the weight center of gravity of an unmanned helicopter. Background Art

[0002] Aircraft weight and center of gravity measurement is an important ground test before the first flight of various types of aircraft. The accuracy of aircraft center of gravity measurement directly affects the flight safety of the aircraft.

[0003] At present, the weight and center of gravity measuring device for skid-type unmanned helicopters is a fixed desktop device. When measuring, the aircraft needs to be placed on a fixed reference platform for measurement. Therefore, it can only be tested at a fixed location on the site, which is not convenient to carry out. Moreover, during the leveling process of the aircraft, the horizontal state of the reference platform is measured and adjusted to confirm whether the plane where the two skid bottoms of the aircraft are located is in a horizontal state, thereby determining whether the aircraft main axis is in a vertical state. This center of gravity measuring device not only has an extremely small horizontal adjustment range, but also, due to assembly errors, the plane where the aircraft main axis and the two skid bottoms of the aircraft are located are not necessarily perpendicular to each other. Therefore, leveling the aircraft by adjusting the horizontal state of the reference platform will affect the measurement accuracy of the aircraft center of gravity position, and the aircraft production quality cannot be guaranteed. In serious cases, it affects the flight safety of the aircraft. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a measurement system and method for the weight and center of gravity of an unmanned helicopter, so as to solve the technical problems of low measurement accuracy and limited measurement scenarios of the existing unmanned helicopter weight and center of gravity measurement system.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions.

[0006] On the one hand, the present invention provides a system for measuring the weight center of gravity of an unmanned helicopter, comprising a weight measuring unit and a distance measuring unit; the weight measuring unit comprises four independent weight measuring components, which are used to respectively measure the weight of the unmanned helicopter at four measuring points; the distance measuring unit comprises a horizontal laser instrument and a laser centering tool, which are used to measure the horizontal positions of the four measuring points; the laser centering tool comprises a mounting part and a tilting part, the mounting part is detachably connected to the main shaft of the unmanned helicopter, and the mounting part is located at the lower end of the tilting part; a laser centering line is provided on the lower surface of the tilting part; the laser centering line is a straight line intersecting with the center line of the main shaft of the unmanned helicopter; the laser centering line can guide the horizontal laser instrument to be arranged in the axial direction of the unmanned helicopter.

[0007] Furthermore, it also includes a horizontal measurement unit, which includes an angle ruler, and the angle ruler is used to measure the verticality of the main axis relative to the horizontal plane.

[0008] Furthermore, the angle ruler includes a first angle ruler and a second angle ruler, and the first angle ruler and the second angle ruler are adsorbed on the main shaft of the unmanned helicopter by magnetic force.

[0009] Furthermore, the weight measurement assembly includes a support and a weighing sensor, and the support is fixed above the weighing sensor.

[0010] Furthermore, the upper surface of the support member is a semi-cylindrical concave surface.

[0011] Furthermore, it also includes a lifting unit, which includes four independent lifting mechanisms and is respectively fixed under the four weighing sensors.

[0012] Furthermore, the weight measuring assembly also includes a base, a slider and a slider support rod. The slider is slidably mounted on the outer periphery of the slider support rod, and both ends of the slider support rod are placed on the base.

[0013] Furthermore, the support member is located below the slider, and the lifting mechanism can drive the support member to fit the slider and support the slider to rise and fall above the base.

[0014] Furthermore, the base is a bracket with a U-shaped cross section, and open grooves are provided above the brackets on both sides of the base, and the two ends of the slider support rod are respectively located in the two open grooves.

[0015] Furthermore, the slider includes an inner sleeve and an outer sleeve, and the inner sleeve and the outer sleeve are rotatably connected via a bearing.

[0016] Furthermore, vertical guide grooves are provided on both sides of the base, and the upper part of the guide groove is connected with the opening groove through a guide hole.

[0017] Furthermore, the weight measurement assembly also includes guide rods, one end of the two guide rods passes through the two guide holes and is fixedly connected to the two ends of the slider support rod.

[0018] Furthermore, the inclined member is a strip plate, and the laser centering line is located on the longitudinal symmetry plane of the inclined member.

[0019] Another aspect of the present invention provides a method for measuring the weight center of gravity of an unmanned helicopter, which uses the unmanned helicopter weight center of gravity measurement system of any one of items 1 to 9 of the first aspect to perform measurement, and includes the following measurement steps:

[0020] Step 1: Arrange equipment: Arrange four weight measurement components and lifting mechanisms at the four measurement points A, B, C, and D respectively;

[0021] Step 2: Place the unmanned helicopter: Place the sled of the unmanned helicopter on the four weight measurement components;

[0022] Step 2: Adjust the horizontal posture: read the measurement value of the horizontal measurement unit, and operate the lifting unit to make the main axis perpendicular to the horizontal plane.

[0023] Step 3: Measure the weight values ​​of four measuring points: record the four weight values ​​MA, MB, MC and MD measured by the four weighing sensors respectively;

[0024] Step 4: Measure the lever arm value: rotate the spindle to make the laser centering line perpendicular to the AC line, and record the distances X and X from the A and C measuring points to the intersection of the vertical line of the horizontal laser instrument and the skid landing gear when the vertical line of the horizontal laser instrument coincides with the laser centering line; rotate the spindle to make the laser centering line perpendicular to the straight line where the C and D measuring points are located; record the distances Y and Y from the C and D measuring points to the vertical line of the horizontal laser instrument when the vertical line of the horizontal laser instrument coincides with the laser centering line;

[0025] Step 5: Calculate the horizontal heading center of gravity and lateral center of gravity of the unmanned helicopter according to the four-point moment balance principle.

[0026] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0027] 1. The measuring system of the present invention is configured as four independent weight measuring components, so that the measuring system has no limitations. It can not only flexibly set the test points to meet the test of different models, but also is easy to carry out, and does not need to be tested only in a fixed place. In addition, the weight measuring components are independent of each other, which is also convenient for daily maintenance, care and replacement of the measuring system.

[0028] 2. The measuring system of the present invention, by setting a laser centering tool, can quickly and accurately arrange the horizontal laser instrument on the heading axis or lateral axis of the unmanned helicopter, thereby reducing the measurement error of the distance value and providing an accurate distance value for calculating the weight center of gravity position of the unmanned helicopter by the four-point weighing method.

[0029] 3. The measuring system of the present invention can adjust the flight direction and the rolling direction horizontally by setting the first angle ruler and the second angle ruler to ensure that the main axis of the unmanned helicopter is perpendicular to the horizontal plane, so that the origin positioning of the measuring plane is more accurate, so that the next measurement process has reliable basic conditions.

[0030] 4. The measuring system of the present invention, by providing a slider that can slide on the slider support rod, can adjust the deformation of the slide by moving the slider left and right on the slider support rod, thereby avoiding the influence of external force on the measured value and effectively improving the measurement accuracy.

[0031] 5. The measuring system of the present invention, by placing the slider support rod on the base and arranging a lifting support member and a weighing sensor under the slider, can not only enable the slider to slide and roll flexibly to achieve adaptive support for the sled, but also enable the slider to be lifted and lowered above the base during testing to achieve leveling and weight measurement of the unmanned helicopter.

[0032] 6. The measuring system of the present invention, by providing a rolling and rotatable outer cover on the slider, can support the weight measuring component under the sled while adjusting its relative position with the sled, thereby avoiding damage to the surface of the sled due to friction and making the position adjustment process convenient and labor-saving.

[0033] 7. The measuring system of the present invention, by setting a guide rod, enables the slider to maintain precise vertical lifting under the guidance of the guide rod, thereby ensuring that the slider support rod is smoothly inserted back into the open groove when falling back, making the measuring process smoother and more efficient.

[0034] 8. The measuring system of the present invention, by setting the inclined member as a strip plate and laser centering line on the longitudinal symmetry plane of the inclined member, simplifies the structure and weight of the laser centering tooling, reduces the impact on the main axis, and can clearly confirm the centering position during testing.

[0035] 9. The measuring method of the present invention can accurately measure the position of the weight center of gravity of an unmanned helicopter by a four-point weighing method by independently performing level adjustment, weight measurement and distance measurement at four measuring points, and is not limited by the measuring site and model. The test process and results are flexible, convenient and accurate.

[0036] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the measurement principle of the four-point weighing method according to an embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of the overall structure of a measurement system according to an embodiment of the present invention;

[0039] Figure 3 It is a structural schematic diagram of a weight measurement assembly and a lifting mechanism according to Embodiment 1 of the present invention;

[0040] Figure 4 It is a schematic diagram of the installation position structure of the level measurement unit and the laser centering tooling according to an embodiment of the present invention;

[0041] Figure 5 A schematic diagram of the structure of a laser centering tool according to an embodiment of the present invention;

[0042] Figure 6 This is a schematic structural diagram of a weight measurement assembly according to Embodiment 2 of the present invention;

[0043] Figure 7 is a schematic cross-sectional structural diagram of a weight measurement assembly according to Embodiment 2 of the present invention;

[0044] Figure 8 This is a schematic diagram of the supporting state structure of the weight measurement component of Example 2 of the present invention;

[0045] Fig. 9 Schematic diagram of the steps of the method for measuring the weight center of gravity of Example 3 of the present invention.

[0046] Reference numerals:

[0047] 1-weight measuring unit; 11-support; 12-weighing sensor; 13-display; 14-base; 141-opening groove; 142-guide groove; 143-guide hole; 144-limiting slideway; 15-slider; 151-inner sleeve; 152-outer sleeve; 1521-retaining ring; 16-slider support rod; 161-threaded blind hole; 17-guide rod; 171-connecting end; 172-rod body; 173-limiting protrusion;

[0048] 2- horizontal measurement unit; 21- first angle ruler; 22- second angle;

[0049] 3-lifting unit; 31-lifting mechanism; 311-limiting slider;

[0050] 4-distance measuring unit; 41-horizontal laser instrument; 42-laser centering tool; 421-mounting piece; 422-tilting piece; 423-laser centering line; 424-angle;

[0051] 5-spindle; 6-sled. DETAILED DESCRIPTION

[0052] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0053] Embodiment 1

[0054] A preferred embodiment of the present invention discloses a system for measuring the weight and center of gravity of an unmanned helicopter, which can accurately measure the weight and center of gravity of a skid-type unmanned helicopter by a four-point weighing method.

[0055] like Figure 1 As shown, the principle of measuring the center of gravity of an object by the four-point weighing method is to measure the weight of the four measuring points of the object, and then calculate the center of gravity of the object by the moment balance formula, and the weight of the object can be measured at the same time. When measuring the center of gravity of the weight of an unmanned helicopter, it is necessary to use the projection center of the main axis 5 of the unmanned helicopter in the horizontal direction as the coordinate origin, and use the heading axis of the unmanned helicopter in the horizontal direction as the X-axis and the lateral axis as the Y-axis to establish a horizontal measurement coordinate system, and measure the center of gravity of the weight of the unmanned helicopter in the horizontal direction.

[0056] The measuring system of this embodiment includes a weight measuring unit 1 , a level measuring unit 2 , a lifting unit 3 and a distance measuring unit 4 .

[0057] like Figure 2 As shown, the weight measurement unit 1 includes four weight measurement components with the same structure and arranged independently. The four weight measurement components are arranged in four coordinate quadrants of the measurement coordinate system respectively, and are used to support the positions of four measuring points A, B, C and D at the bottom of two skids 6 of the unmanned helicopter to measure the weight values ​​MA, MB, MC and MD of the unmanned helicopter at the four measuring points.

[0058] like Figure 2 and Figure 3 As shown, the weight measurement assembly includes a support 11, a weighing sensor 12 and a display 13. The support 11 is fixed above the weighing sensor 12, and a semi-cylindrical groove is provided on the top of the support 11. The width of the groove needs to be wider than the width of the unmanned helicopter sled 6 to ensure that the sled 6 can be stably placed in the groove. The weighing sensor 12 is connected to the display 13 through a signal line, and the measured weight value is displayed on the display 13. Optionally, the four weight measurement assemblies 1 can also share a display 13 to display the measured values ​​of each weighing sensor 12 respectively.

[0059] In this embodiment, by configuring the weight measurement unit 1 to be four independent weight measurement components, the measurement system is not limited. Not only can the test points be flexibly set to meet the test of different models, but it is also easy to carry out and does not need to be tested only in a fixed place. In addition, the weight measurement components are independent of each other, which is also convenient for daily maintenance, care and replacement of the measurement system.

[0060] like Figure 2 and Figure 4 As shown, the level measurement unit 2 includes a first angle ruler 21 and a second angle ruler 22, which are used to measure and determine whether the unmanned helicopter is in a horizontal posture. Preferably, the first angle ruler 21 and the second angle ruler 22 are bubble-type digital display angle rulers. During measurement, one side of the first angle ruler 21 and the second angle ruler 22 is magnetically adsorbed on the main shaft 5 of the unmanned helicopter.

[0061] like Figure 2 and Figure 3 As shown, the lifting unit 3 includes four independent lifting mechanisms 31, which are respectively fixed under the four weighing sensors 12. The four lifting mechanisms 31 can respectively drive the support 11 and the weighing sensors 12 to rise and fall, so as to respectively adjust the heights of the four measuring points of the unmanned helicopter, so that the unmanned helicopter is finally in a horizontal posture. Preferably, the lifting mechanism 31 is a hydraulic lifting mechanism.

[0062] Preferably, the steps of adjusting the level of the unmanned helicopter in this embodiment are as follows:

[0063] 1) The first angle ruler 21 and the second angle ruler 22 are cleared at the same time after being superimposed on each other;

[0064] 2) Adsorb the first angle ruler 21 onto the main axis 5 of the unmanned helicopter in the direction of the flight path;

[0065] 3) Leveling the route direction: adsorb the second angle ruler 22 on the main shaft, with the direction 180 degrees different from the first angle ruler 21, observe the bubbles on the first angle ruler 21 and the second angle ruler 22, raise the lifting mechanism 31 of the two measuring points on the lower side of the bubble, and control the numerical difference between the first angle ruler 21 and the second angle ruler 22 within ±0.2°;

[0066] 4) Leveling in the rolling direction: keep the position of the first angle ruler 21 unchanged, reset the second angle ruler 22, and rotate the direction by 90°; adjust the lifting mechanism 31 to control the value of the second angle ruler 22 within 0.2°;

[0067] 5) Complete the horizontal adjustment of the unmanned helicopter.

[0068] In this embodiment, the first angle ruler 21 and the second angle ruler 22 are arranged, and the first angle ruler 21 and the second angle ruler 22 are adsorbed on the main shaft 5 of the unmanned helicopter by magnetic force, and the flight direction and the rolling direction are adjusted horizontally respectively to ensure that the main shaft 5 of the unmanned helicopter can be perpendicular to the horizontal plane, so that the origin positioning of the measurement plane is more accurate, so that the next measurement process has reliable basic conditions.

[0069] like Figure 1 and Figure 4 As shown, the distance measuring unit 4 includes a horizontal laser instrument 41 and a laser centering tool 42. The number of horizontal laser instruments 41 can be arranged according to the number of measuring points, and the same horizontal laser instrument can also be used to measure each measuring point separately.

[0070] like Figure 4 and Figure 5As shown, the laser centering tool 42 includes a mounting part 421, a tilting part 422 and a laser centering line 423. The laser centering tool 42 is used to assist in arranging the horizontal laser instrument 41 at a position where the vertical line coincides with the axis of the route direction of the unmanned helicopter or the lateral axis during the measurement process. During measurement, the laser centering tool 42 needs to be fixed to the mounting surface on the main shaft 5 of the unmanned aerial vehicle through the mounting part 421. It should be noted that due to the different structures of the main shaft 5 of different models, the mounting surface on the main shaft 5 may also be different. In order to facilitate positioning and installation, preferably, this embodiment is described by taking the mounting surface perpendicular to the horizontal plane set on the main shaft 5 of the unmanned helicopter as an example.

[0071] like Figure 5 As shown, preferably, the laser centering tool 42 includes a mounting member 421 and a tilting member 422. The mounting member 421 is a flat plate with multiple mounting holes, which can be detachably connected to the main shaft 5 of the unmanned helicopter by screws; the tilting member 422 is a strip plate, and the mounting member 421 is located at the lower end of the tilting member 422, and has an angle 424 with the tilting member 422, so that when the laser centering tool 42 is installed on the main shaft 5, the tilting member 422 tilts upward along the radial direction of the main shaft 5. The lower surface of the tilting member 422 is provided with a laser centering line 423. Preferably, the laser centering line 423 is located on the longitudinal symmetry plane of the tilting member 422, so that the laser centering line 423 and the center line of the main shaft 5 are on the same plane. The laser centering tool 42 can guide the horizontal laser instrument 41 to adjust its position so that the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423, thereby confirming that the arrangement position of the horizontal laser instrument 41 is located on the axis center line of the unmanned helicopter, which plays a role in position centering.

[0072] Preferably, the angle 424 is in the range of 30°-60°, so that the laser centering line 423 can be observed prominently on the ground. In order to make the laser centering line 423 more convenient and accurate to observe, the laser centering tool 42 can be formed in one step using white engineering plastic, the laser centering line 423 uses a red line, and the vertical line of the horizontal laser instrument 41 also uses a red laser line.

[0073] The distance measurement unit 4 of this embodiment performs distance measurement in the following steps:

[0074] 1) Fix the laser centering tool 42 on the main shaft 5, rotate the main shaft 5, and make the laser centering line 423 perpendicular to the straight line where the A and C measuring points are located;

[0075] 2) Adjust the position of the horizontal laser instrument 41 so that the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423;

[0076] 3) Record the distances X2 and X1 from the measuring points A and C to the intersection of the vertical line of the horizontal laser instrument 41 and the landing gear of the skid 6 respectively;

[0077] 4) Rotate the main axis 5 to make the laser centering line 423 perpendicular to the straight line where the C and D measuring points are located;

[0078] 5) Adjust the position of the horizontal laser instrument 41 so that the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423;

[0079] 6) Record the distances Y1 and Y2 from the C and D measuring points to the vertical line of the horizontal laser instrument 41 respectively.

[0080] like Figure 1 As shown, according to the measurement data of the measuring device of this embodiment, the weight center of gravity of the unmanned helicopter can be accurately calculated through the four-point weighing method moment balance principle. The four-point weighing method moment balance principle calculates the heading center of gravity position and lateral center of gravity position of the unmanned helicopter in the horizontal direction through the following moment balance formula:

[0081] x=(MC+MD)*X1-(MA+MB)*X2 / (MA+MB+MC+MD)

[0082] y=(MA+MC)*Y1-(MB+MD)*Y2 / (MA+MB+MC+MD)

[0083] Wherein: x is the heading center of gravity coordinate of the unmanned helicopter, y is the lateral center of gravity coordinate of the unmanned helicopter, MA, MB, MC, MD are the values ​​measured by weight measurement unit 1 at measurement points A, B, C, D respectively, X1 is the distance from the origin to the line connecting measurement points C and D, X2 is the distance from the origin to the line connecting measurement points A and C, Y1 is the distance from the origin to the line connecting measurement points A and C, and Y2 is the distance from the origin to the line connecting measurement points B and D.

[0084] The measurement system of this embodiment can calibrate the arrangement position of the horizontal laser instrument 41 when measuring the weight center of gravity of the unmanned helicopter by setting the laser centering tool 42. When the position of the horizontal laser instrument 41 is not on the X-axis or Y-axis, since the laser centering line 423 is inclined to the horizontal plane, the vertical line of the horizontal laser instrument 41 cannot completely coincide with the laser centering line 423; adjust the position of the horizontal laser instrument 41, when the vertical line of the horizontal laser instrument 41 completely coincides with the laser centering line 423, it indicates that the horizontal laser instrument 41 is located on the X-axis or Y-axis, and the vertical line of the horizontal laser instrument 41 coincides with the heading axis or lateral axis of the unmanned helicopter, thereby reducing the measurement error of the distance values ​​X1, X2 or Y1, Y2, and finally obtaining an accurate weight center of gravity position.

[0085] Example 2

[0086] The measurement system of the weight center of gravity of the unmanned helicopter disclosed in this embodiment is different from that in the first embodiment in that the structure of the weight measurement component in the weight measurement unit 1 is different.

[0087] like Figure 6 and Figure 7 As shown, considering that when the unmanned helicopter is hoisted onto the weight measurement unit 1, the sled 6 of the unmanned helicopter will be deformed to a certain extent after being located in the groove of the support 11, thereby generating contact stress. In order to avoid external forces affecting the measurement accuracy, the weight measurement assembly of this embodiment also includes a base 14, a slider 15, a slider support rod 16 and a guide rod 17, and the slider 15 is placed on the base 14 through the slider support rod 16.

[0088] In a preferred solution of this embodiment, the base 14 is a bracket with a U-shaped cross section, and an opening groove 141 is provided above the brackets on both sides of the base 14, and the two ends of the slider support rod 16 are respectively located in the two opening grooves 141. Preferably, the cross section of the opening groove 141 is "T" shaped, and the slider support rod 16 is a straight rod with a "T" shaped cross section, and the outer surface of the slider support rod 16 matches the inner wall of the opening groove 141.

[0089] Furthermore, the slider 15 is a cylinder sleeved on the outside of the slider support rod 16, and is used to support the skid 6 of the unmanned helicopter. A through slot is provided on the axis of the cylinder of the slider 15, and the cross section of the through slot matches the "T"-shaped cross section of the slider support rod 16, so that the slider 15 can slide on the slider support rod 16 along the axis of the slider 15.

[0090] Furthermore, the support member 11, the weighing sensor 12 and the lifting mechanism 31 are located between the base 14 and the slider 15, and the cylindrical outer surface of the slider 15 matches the semi-cylindrical inner wall of the support member 11. Figure 6 As shown, when the unmanned helicopter is placed on the slider 15, the support member 11 and the slider 15 are separated. Figure 8 As shown, when the lifting mechanism 31 drives the support member 11 and the weighing sensor 12 to rise, the inner wall of the support member 11 can fit with the outer surface of the slider 15, and support the slider 15 and the slider support rod 16 to separate from the base 14, and rise and fall above the base, thereby adjusting the height of the skid 6 of the unmanned helicopter at the measuring point.

[0091] When using the measurement system of this embodiment for measurement, the weight measurement unit 1 and the lifting unit 3 are arranged at four measurement points according to the measurement steps of Example 1, and the axis lines of the four sliders 15 need to be arranged perpendicular to the sled 6 of the unmanned helicopter; then the sled 6 of the unmanned helicopter is pressed on the four sliders 15, and the slider 15 is allowed to move left and right on the slider support rod 16 and stabilize due to deformation of the landing gear of the slider 6; the lifting mechanism 31, the weighing sensor 12 and the support member 11 are moved so that the support member 11 is located directly below the slider 15 to ensure that the force point of the weighing sensor 12 is in the middle position; the lifting mechanism 31 is started so that the support member 11 rises and contacts the slider 15 and fits each other to ensure that the contact part is fully stressed, and the lifting of the lifting mechanism 31 is stopped after the slider support rod 16 is separated from the opening groove 141. Next, the level adjustment, distance measurement and weight measurement of the unmanned helicopter can be continued according to the steps of Example 1.

[0092] The measurement system of this embodiment, by providing a slider 15 capable of sliding on a slider support rod 16 on the weight measurement unit 1, can adjust the deformation of the sled 6 by moving the slider 15 left and right on the slider support rod 16 when the unmanned helicopter is hoisted onto the weight measurement unit 1, thereby avoiding the influence of external force on the measured value and effectively improving the measurement accuracy. In addition, the slider 15 is movably connected to the base 14 through the slider support rod 16, and a support member 11 and a weighing sensor 12 capable of lifting and lowering are provided below the slider 15, so that the slider 15 can slide and roll flexibly, and can also be lifted and lowered above the base 14 during testing, thereby realizing the leveling and weight measurement of the unmanned helicopter.

[0093] Further, such as Figure 7 As shown, the base 14 is provided with a limiting slide 144, which is parallel to the slider support rod 16, and the bottom of the lifting mechanism 31 is located in the limiting slide 144. Preferably, the limiting slide 144 is a linear groove on the upper surface located at the bottom of the base 14, and the cross section of the linear groove is a "T" shape. The bottom of the lifting mechanism 31 is provided with a limiting slider 311 with an inverted "T" cross section, and the limiting slider 311 is located in the limiting slide 144, which can stably assemble the lifting mechanism 31 on the base 14 and make the support member 11 located directly below the slider 15; it can also push the lifting mechanism 31 to move along the limiting slide 144 after the slider 15 slides on the slider support rod 16, so that the support member 11 moves to the directly below the slider 15 under the guiding action of the limiting slide 144, ensuring that the support member 11 fully supports the slider 15, so as to obtain accurate and reliable weight measurement data.

[0094] Further, such as Figure 7As shown, the slider 15 also includes an inner sleeve 151 and an outer sleeve 152, and the inner sleeve 151 and the outer sleeve 152 are rotatably connected via a bearing. When the unmanned helicopter is hoisted onto the weight measurement unit 1, if the position of the measuring point needs to be adjusted, the base 14 can be moved along the direction of the sled 6. Since the outer sleeve 152 can roll and rotate outside the inner sleeve 151, the weight measurement component can be supported under the sled 6 while adjusting its relative position with the sled 6, which not only avoids damage to the surface of the sled 6 caused by friction, but also makes the position adjustment process convenient and labor-saving.

[0095] Further, such as Figure 7 As shown, the guide rod 17 is two cylindrical rods, and the guide rod 17 includes a connecting end 171, a rod body 172 and a limiting protrusion 173. The connecting end 171 and the limiting protrusion 173 are respectively located at two ends of the guide rod 17.

[0096] Optionally, the connection end 171 is provided with external threads. Both ends of the slider support rod 16 are provided with threaded blind holes 161 matching the external threads of the connection end 171, the openings of the two threaded blind holes 161 face downward, and the two guide rods 17 are fixedly connected to the two ends of the slider support rod 16 through threads.

[0097] Optionally, as shown in the figure, the brackets on both sides of the base 14 are provided with vertical guide grooves 142, and the width of the guide grooves 142 matches the width of the limiting protrusions 173; the top of the guide grooves 142 is connected to the opening groove 141 through a guide hole 143, and the diameter of the guide hole 143 matches the diameter of the rod body 172.

[0098] As shown in Figure X, when weight measurement and horizontal adjustment are performed, the lifting mechanism 31 drives the support member 11 to support the slider 15 and the slider support rod 16 to rise and fall. The slider support rod 16 can maintain precise vertical lifting under the guidance of the guide rod 17, and can ensure that the slider support rod 16 is smoothly inserted back into the opening groove 141 when falling back, making the measurement process smoother and more efficient.

[0099] In order to prevent the sled 6 from moving sideways on the slider 15 during the measurement process, retaining rings 1521 are provided at both ends of the outer sleeve 152. The retaining rings 1521 are convex rings protruding from the outer circumference of the outer sleeve 152. The distance between the opposite surfaces of the two retaining rings 1521 matches the width of the sled 6, which can prevent the sled 6 on the slider 15 from moving sideways. Preferably, the shapes of the opposite surfaces of the two retaining rings 1521 match the shapes of the outer surfaces of the two sides of the sled 6, so as to increase the contact area between the retaining rings 1521 and the sled 6.

[0100] Example 3

[0101] This embodiment discloses a method for measuring the weight center of gravity of an unmanned helicopter, using the measurement system of the weight center of gravity of the unmanned helicopter of Embodiment 1 or Embodiment 2. Fig. 9 As shown, the specific measurement steps include the following:

[0102] Step S100: Arrange equipment: Arrange four weight measurement components and the lifting mechanism 31 at four measurement points A, B, C, and D respectively;

[0103] Step S200: placing the unmanned helicopter: placing the sled 6 of the unmanned helicopter on four weight measurement components;

[0104] Step S300: Adjusting the horizontal posture: reading the measurement value of the horizontal measurement unit 2, and operating the lifting unit 3 to make the main axis 5 perpendicular to the horizontal plane.

[0105] Step S400: measuring the weight values ​​of four measuring points: recording the four weight values ​​MA, MB, MC and MD measured by the four weighing sensors 12 respectively;

[0106] Step S500: measuring the lever arm value: rotating the main shaft 5 so that the laser centering line 423 is perpendicular to the AC line, recording the distances X2 and X1 from the A and C measuring points to the intersection of the vertical line of the horizontal laser instrument 41 and the landing gear of the sled 6 when the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423; rotating the main shaft 5 so that the laser centering line 423 is perpendicular to the straight line where the C and D measuring points are located; recording the distances Y1 and Y2 from the C and D measuring points to the vertical line of the horizontal laser instrument 41 when the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423;

[0107] Step S600: Calculate the heading center of gravity position and lateral center of gravity position of the unmanned helicopter in the horizontal direction according to the four-point moment balance principle.

[0108] Preferably, Figure 1 As shown, the four measuring points A, B, C, and D are rectangles, wherein the distance between the AC line and the BD line needs to be determined according to the distance between the bottoms of the two sleds 6 of different models so that the sleds can be placed on the four weight measuring components.

[0109] The measurement method of this embodiment can accurately measure the position of the weight center of gravity of the unmanned helicopter through the four-point weighing method by independently performing level adjustment, weight measurement and distance measurement at four measuring points, and is not limited by the measurement site and model. The test process and results are flexible, convenient and accurate.

[0110] Preferably, step S200 includes the following sub-steps:

[0111] S210 places the skid 6 of the unmanned helicopter on four slide blocks 15;

[0112] S220 After the four slide blocks 15 are stable, the lifting mechanism 31, the weighing sensor 12 and the support member 11 are moved so that the support member 11 is located directly below the slide blocks 15;

[0113] S230: Activate the four lifting mechanisms 31 to move the support member 11 upward to contact and fit the slider 15 until the slider support rod 16 is separated from the opening groove 141.

[0114] In step S200 of this embodiment, by setting sub-step S220, sub-step S230 is executed after the four sliders 15 are stable, so that the sled 6 of the unmanned helicopter can effectively release the stress generated by deformation, thereby avoiding the influence of external force on the measured value and effectively improving the measurement accuracy.

[0115] Preferably, step S300 includes the following sub-steps:

[0116] S310 clears the first angle ruler 21 and the second angle ruler 22 simultaneously after they are superimposed on each other;

[0117] S320: adsorb the first angle ruler 21 on the main axis 5 of the unmanned helicopter, with the direction being the heading;

[0118] S330 performs route direction leveling: the second angle ruler 22 is adsorbed on the main shaft, and the direction is 180° different from the first angle ruler 21, and the lifting mechanism 31 is operated to control the difference between the first angle ruler 21 and the second angle ruler 22 within ±0.2°;

[0119] S340 performs rolling direction leveling: keep the position of the first angle ruler 21 unchanged, reset the second angle ruler 22, and rotate the direction by 90°; operate the lifting mechanism 31 to control the value of the second angle ruler 22 within 0.2°;

[0120] S350 completes the horizontal adjustment of the unmanned helicopter.

[0121] In step S300 of this embodiment, the flight direction and the rolling direction are adjusted horizontally by taking the main axis 5 of the unmanned helicopter as a reference, thereby ensuring that the main axis 5 of the unmanned helicopter can be perpendicular to the horizontal plane, thereby making the origin positioning of the measurement plane more accurate, so that the next measurement process has reliable basic conditions.

[0122] Preferably, step S500 includes the following sub-steps:

[0123] S510: fix the laser centering tool 42 on the main shaft 5, rotate the main shaft 5, and make the laser centering line 423 perpendicular to the straight line where the A and C measuring points are located;

[0124] S520 adjust the position of the horizontal laser instrument 41 so that the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423;

[0125] S530 records the distances X2 and X1 from the measuring points A and C to the intersection of the vertical line of the horizontal laser instrument 41 and the landing gear of the skid 6 respectively;

[0126] S540 rotates the main axis 5 to make the laser centering line 423 perpendicular to the straight line where the C and D measuring points are located;

[0127] S550 adjust the position of the horizontal laser instrument 41 so that the vertical line of the horizontal laser instrument 41 coincides with the laser centering line 423;

[0128] S560 records the distances Y1 and Y2 from the C and D measuring points to the vertical line of the horizontal laser instrument 41 respectively.

[0129] In step S500 of this embodiment, by setting sub-steps S510, S520, S540, and S550, the arrangement position of the horizontal laser instrument 41 can be calibrated when measuring the weight center of gravity of the unmanned helicopter, thereby reducing the measurement error of the distance values ​​X1, X2 or Y1, Y2, and finally obtaining an accurate weight center of gravity position.

[0130] In step S600, the heading center of gravity position and the lateral center of gravity position of the unmanned helicopter in the horizontal direction are calculated according to the torque balance principle of the four-point weighing method:

[0131] x=(MC+MD)*X1-(MA+MB)*X2 / (MA+MB+MC+MD)

[0132] y=(MA+MC)*Y1-(MB+MD)*Y2 / (MA+MB+MC+MD)

[0133] Wherein: x is the heading center of gravity coordinate of the unmanned helicopter, y is the lateral center of gravity coordinate of the unmanned helicopter, MA, MB, MC, MD are the values ​​measured by weight measurement unit 1 at measurement points A, B, C, D respectively, X1 is the distance from the origin to the line connecting measurement points C and D, X2 is the distance from the origin to the line connecting measurement points A and C, Y1 is the distance from the origin to the line connecting measurement points A and C, and Y2 is the distance from the origin to the line connecting measurement points B and D.

[0134] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A system for measuring the weight center of an unmanned helicopter, characterized in that: It comprises a weight measuring unit (1) and a distance measuring unit (4); The weight measurement unit (1) comprises four independent weight measurement components, which are used to measure the weight of the unmanned helicopter at four measurement points respectively; The distance measuring unit (4) comprises a horizontal laser instrument (41) and a laser centering tool (42), and is used to measure the positions of four measuring points in the horizontal direction; The laser centering tool (42) comprises a mounting member (421) and a tilting member (422), wherein the mounting member (421) is detachably connected to the main shaft (5) of the unmanned helicopter, and the mounting member (421) is located at the lower end of the tilting member (422); The lower surface of the tilting member (422) is provided with a laser centering line (423) for guiding the horizontal laser instrument (41) to be arranged in the axial direction of the unmanned helicopter.

2. The unmanned helicopter weight center of gravity measurement system according to claim 1, characterized in that: The laser centering line (423) is a straight line intersecting with the center line of the main axis (5) of the unmanned helicopter.

3. The unmanned helicopter weight center of gravity measurement system according to claim 2, characterized in that: It also comprises a horizontal measurement unit (2), wherein the horizontal measurement unit (2) comprises an angle ruler, and the angle ruler is used to measure the verticality of the main axis (5) relative to the horizontal plane.

4. The unmanned helicopter weight center of gravity measurement system according to claim 3, characterized in that: The angle ruler comprises a first angle ruler (21) and a second angle ruler (22), wherein the first angle ruler (21) and the second angle ruler (22) are adsorbed on the main shaft (5) of the unmanned helicopter by magnetic force.

5. The unmanned helicopter weight center of gravity measurement system according to claim 1, characterized in that: The weight measurement assembly comprises a support member (11) and a weighing sensor (12), wherein the support member (11) is fixed above the weighing sensor (12).

6. The unmanned helicopter weight center of gravity measurement system according to claim 1, characterized in that: It also comprises a lifting unit (3), wherein the lifting unit (3) comprises four independent lifting mechanisms (31) and is respectively fixed below the four weighing sensors (12).

7. The unmanned helicopter weight center of gravity measurement system according to claim 6, characterized in that: The weight measuring assembly further comprises a base (14), a slider (15) and a slider support rod (16); the slider (15) is slidably mounted on the outer periphery of the slider support rod (16); and both ends of the slider support rod (16) are placed on the base (14).

8. The unmanned helicopter weight center of gravity measurement system according to claim 7, characterized in that: The support member (11) is located below the slider (15), and the lifting mechanism (31) can drive the support member (11) to fit the slider (15) and support the slider (15) to be lifted and lowered above the base (14).

9. The unmanned helicopter weight center of gravity measurement system according to any one of claims 1 to 8, characterized in that: The inclined member (422) is a strip-shaped plate, and the laser centering line (423) is located on a longitudinal symmetric plane of the inclined member (422).

10. A method for measuring the weight center of an unmanned helicopter, characterized in that: The measurement of the weight center of gravity of the unmanned helicopter using the measurement system of any one of claims 1 to 9 comprises the following measurement steps: Step 1: Arrange the equipment: Arrange the four weight measuring components and the lifting mechanism (31) at the four measuring points A, B, C and D respectively; Step 2: Placing the unmanned helicopter: placing the sled (6) of the unmanned helicopter on the four weight measuring components; Step 2: Adjust the horizontal posture: read the measurement value of the horizontal measurement unit (2), operate the lifting unit (3) to make the main axis (5) perpendicular to the horizontal plane. Step 3: measuring the weight values ​​of four measuring points: recording the four weight values ​​MA, MB, MC and MD measured by the four weighing sensors (12) respectively; Step 4: Measure the force arm value: rotate the main shaft (5) to make the laser centering line (423) perpendicular to the AC line, record the distances X2 and X1 from the A and C measuring points to the intersection of the vertical line of the horizontal laser instrument (41) and the landing gear of the sled (6) when the vertical line of the horizontal laser instrument (41) coincides with the laser centering line (423); rotate the main shaft (5) to make the laser centering line (423) perpendicular to the straight line where the C and D measuring points are located; Recording the distances Y1 and Y2 between the C and D measuring points and the vertical line of the horizontal laser instrument (41) when the vertical line of the horizontal laser instrument (41) coincides with the laser centering line (423); Step 5: Calculate the horizontal heading center of gravity and lateral center of gravity of the unmanned helicopter according to the four-point moment balance principle.

Images