Method and device for measuring drop shock test load of unmanned helicopter with skid landing gear

Abstract

The invention discloses a method and device for measuring the load of a drop shock test of an unmanned helicopter with a skid-type landing gear. The device comprises a load measurement system, an unmanned helicopter simulation test piece, a ground support system and a lifting control system; the lifting control system is arranged on the ground support system, and is used to lift the unmanned helicopter simulation test piece, complete the double-skid landing and / or forward flight or side flight landing of the unmanned helicopter simulation test piece, and control the drop height of the unmanned helicopter simulation test piece; the load measurement system is arranged on a support platform of the ground support system, and is used to collect the impact load and acceleration of the unmanned helicopter simulation test piece when landing; the method obtains the dynamic response of the unmanned helicopter drop shock test load sensor and the acceleration sensor by using a dynamic acquisition system, and obtains its equivalent ground impact load, thereby solving the problem that the feedback load cannot be accurately identified and measured when the unmanned helicopter landing gear falls to the ground.

Description

Technical Field

[0001] The invention belongs to the technical field of drop shock test of unmanned helicopters, in particular to a method and a device for measuring ground impact load of a drop shock test of an unmanned helicopter with a skid-type landing gear. Background Art

[0002] In order to improve the quality of aircraft and ensure the flight safety of aircraft, various aircraft design institutes and other R&D and testing institutions usually use drop tests to obtain the dynamic response and impact load of the aircraft during landing to guide aircraft design; reasonable test plans and suitable measurement methods are important indicators that determine the accuracy and authenticity of drop tests. However, the three-dimensional measurement platform used in the drop test of large aircraft has a complex structure, large space, large impact resistance tonnage, low dynamic response sensitivity for small mass test pieces, and high cost. For the design and development of small aircraft, especially unmanned helicopters, the R&D cost is limited, the design cycle is short, the body tonnage is small, the impact response sensitivity is high, and the aircraft maneuverability requirements are low. Therefore, it is not suitable to use such test equipment for drop tests.

[0003] In addition, the current scope and methods of this type of drop shock test only consider the double-skid landing condition, while ignoring the situation of side flight or forward flight landing with speed. However, for helicopters with skid landing gear, forward flight or side flight landing with speed is a common phenomenon during their use. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for measuring the drop test load of an unmanned helicopter with a skid-type landing gear, so as to realize the measurement of the impact load during the drop test of the unmanned helicopter.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] A load measuring device for a drop shock test of an unmanned helicopter with a skid-type landing gear, comprising a load measuring system, an unmanned helicopter simulation test piece, a ground support system and a lifting control system;

[0007] The lifting control system is arranged on the ground support system, and is used to lift the unmanned helicopter simulation test piece, complete the double-sled vertical landing and the forward flight or side flight landing with speed of the unmanned helicopter simulation test piece, and control the falling height of the unmanned helicopter simulation test piece;

[0008] The load measurement system is arranged on the support platform of the ground support system, and is used to collect the impact load and acceleration of the unmanned helicopter when the simulated test piece lands.

[0009] A method for measuring ground impact load of a drop test of an unmanned helicopter with a skid landing gear comprises the following steps:

[0010] Step 1: Arrange the load measurement system and build the ground support system;

[0011] Step 2, assemble the unmanned helicopter simulation test piece, and adjust the weight, quantity and position of the configuration blocks on the simulation fuselage frame;

[0012] Step 3: Place the unmanned helicopter simulation test piece on the drop platform, and adjust its front, back, left, and right positions to ensure that the lifting suction cup is coaxial with the suspended electromagnet;

[0013] Step 4: Use the lifting control box to control the electromagnet to be energized. After being energized, the electromagnet generates magnetic force to adsorb the unmanned helicopter simulation test piece and lift it to a certain height; by adjusting the leveling weight of the fuselage center of gravity adjustment device and observing the angle ruler placed on the pitch and roll directions of the simulated fuselage frame, the center of gravity of the unmanned helicopter simulation test piece can be fine-tuned to ensure that it is not eccentric when falling;

[0014] Step 5: Conduct a landing test to obtain data collected by the sensor.

[0015] Compared with the prior art, the present invention has the following significant advantages:

[0016] (1) The present invention obtains the dynamic response of the load sensor and acceleration sensor of the unmanned helicopter drop shock test by using a dynamic acquisition system, and obtains its equivalent ground impact load based on mechanical balance and dynamic signal filtering processing methods, thereby solving the problem that the feedback load of the unmanned helicopter landing gear cannot be accurately identified and measured when it falls to the ground.

[0017] (2) The impact load measurement device is modular in design, easy to load and unload, and occupies a small space. It is suitable for obtaining ground impact loads in unmanned helicopter skid landing gear drop tests and other product drop tests. The measurement device can be personalized and combined according to the test object, test requirements, and laboratory hardware and software conditions.

[0018] (3) The device can not only complete the traditional double-skid vertical landing test conditions, but also the helicopter-specific side landing and forward landing test conditions with speed that traditional test devices cannot complete. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Assembly diagram of the ground impact load measurement device for the drop shock test of an unmanned helicopter with a skid-type landing gear.

[0020] Figure 2 This is the structural diagram of the load measurement system.

[0021] Figure 3 This is the structural diagram of the unmanned helicopter simulation test piece.

[0022] Figure 4This is a drop shock test diagram for forward flight conditions with speed.

[0023] Figure 5 This is a drop shock test diagram for side-flying conditions with speed.

[0024] Figure 6 This is the installation diagram of the electric traction device.

[0025] Figure 7 This is a diagram of the composition of the electric traction device.

[0026] Figure 8 This is a theoretical calculation diagram for the lateral or forward initial velocity.

[0027] Fig. 9 This is a theoretical analysis diagram of the impact load of the drop test. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] Combination Figure 1 The present embodiment provides a method and device for measuring the load in a drop test of an unmanned helicopter with a skid-type landing gear, which comprises a load measurement system 10, an unmanned helicopter simulation test piece 20, a ground support system 30 and a lifting control system 40; wherein the ground support system 30 is used to support and fix the test system, and the lifting control system 40 is used to control the test drop height of the unmanned helicopter simulation test piece 20; the load measurement system 10 is used to collect and process test data during the drop test.

[0030] Combination Figure 2The load measurement system 10 includes a drop platform 11, a support adapter plate 12, a load sensor 13, mounting bolts 14, an acceleration sensor 15 and a dynamic acquisition instrument system (including a dynamic acquisition instrument and a computer), not shown in the figure; wherein the drop platform 11 is a flat plate with strong rigidity and hardness, and its material can be made of metal, concrete or composite materials. The drop platform 11 is divided into two pieces, corresponding to the two sleds at the bottom of the unmanned helicopter simulation test piece 20; three or more mounting holes matching the load sensor are arranged on the four sides of the drop platform 11, and a mounting hole matching the acceleration sensor 15 is reserved in the center, and a number of mounting holes for installing loading and unloading ears are arranged at the outer edges of the four corners of the drop platform 11; the support adapter plate 12 is a square steel plate, and a mounting hole matching the load sensor 13 is prefabricated in the center, and rectangular grooves are opened on the four sides of the support adapter plate 12, which is connected to the support platform 33 by using mounting bolts 14, and the support platform 33 is on It is provided with a mounting groove, into which the bolt head is inserted, and the support adapter plate 12 is connected to the support platform 33; the load sensor 13 and the acceleration sensor 15 need to be matched and selected according to the test object, test requirements and laboratory hardware and software conditions; its load sensor 13 is fixed between the drop platform 11 and the support adapter plate 12 according to the required installation method, that is, three or more load sensors 13 are used as the fulcrum of the drop platform 11 and are located on the corresponding support adapter plate 12. During the installation process, please note that the installation adjustment process can be calibrated with a level to ensure that the drop platform 11 remains level. The ground load measurement device 10 is characterized in that it is fixedly connected to the support platform 33 of the ground support 30 as a whole using mounting bolts 14;

[0031] Combination Figure 3The unmanned helicopter simulation test piece 20 includes an unmanned helicopter landing gear 21 and a simulated fuselage frame 22, a fuselage center of gravity adjustment device 23, a lifting suction cup 24 and a counterweight block 25, wherein the structure of the simulated fuselage frame 22 can be a metal frame plate or any other structure. According to the requirements of the prototype of the test object, an unmanned helicopter landing gear 21 is provided at the bottom of the simulated fuselage frame 22; a plurality of counterweight blocks 25 are arranged at the four corners of the simulated fuselage frame 22 to ensure that its characteristic indicators such as weight, center of gravity and moment of inertia can describe the prototype of the test object; the lifting suction cup 24 is a steel metal block with a threaded hole in the center, which is fastened to the metal column with external threads on the upper end of the cross beam of the center of gravity section of the simulated fuselage frame 22, so that it is adsorbed by an energized electromagnet 43 to realize the overall lifting of the unmanned helicopter simulation test piece 20. The fuselage center of gravity adjustment device (23) is composed of four joints 23-1, four round tube rods 23-2 with matching lengths, and leveling weights 23-3 that can move on the round tube rods; the four corners of the upper end of the fuselage frame 22 are respectively provided with joints 23-1, and four round tube rods 23-2 are connected between the four joints to form a rectangular structure; by observing the pitch and roll directions of the simulated fuselage frame 22, the angle ruler is placed, and the positions of the four leveling weights 23-3 on their respective round tube rods 23-2 are adjusted to achieve fine adjustment of the center of gravity of the unmanned helicopter simulation test piece 20.

[0032] Combination Figure 1 The ground support system 30 includes a crossbeam 31, a column 32, a support platform 33 and a guide rail 34; two columns 32 are fixed on the support platform 33; the crossbeam 31 with good bending stiffness is installed between the two columns 32, and the three are built to form a "gantry" structure fixed on the support platform 33 to provide support for the drop shock test system;

[0033] Combination Figure 4-Figure 7 The lifting control system 40 includes a lifting control box 41, a chain pulley assembly 42 and an electromagnet 43; a motor and a chain sprocket are arranged in the lifting control box 41; the motor drives the sprocket to rotate and adjusts the lifting and lowering of the chain pulley assembly 42; wherein the lifting control box 41 adjusts the lifting and lowering of the chain pulley assembly 42 and the power on and off of the electromagnet 43 through a PLC programmable controller; the electromagnet 43 is suspended on the hook of the chain pulley assembly 42, and its generation and disappearance of magnetic force is controlled by power on and off.

[0034] For the double skid landing test condition,

[0035] The unmanned helicopter simulation test piece 20 is raised to the required test height by controlling the chain pulley assembly 42 through the control of the lifting control box 41; the power supply of the electromagnet 43 is disconnected, and the unmanned helicopter simulation test piece 20 freely falls to the drop platform 11 at the required height, and data collection is stopped after it stabilizes;

[0036] For the forward flight landing test condition with speed or the side flight landing test condition, the hoisting control system 40 also includes an electric traction device 44; the electric traction device 44 is composed of a traction guide rail 44-1, a traction roller 44-2, a traction roller shaft 44-3, a traction drive 44-4, a traction connection seat 44-5 and a traction wire rope 44-6; the traction guide rail 44-1 is fixed on the crossbeam 31 by two screws, and the traction guide rail 44-1 is installed at a certain angle by adjusting the length of the screws; the traction roller shaft 44-3 rotates with the traction roller 44-2 and installs it in the slide groove of the traction guide rail 44-1. The extended end of the traction roller shaft 44-3 is fixedly connected to the mounting rod of the hoisting control box 41 by bolts. The traction drive 44-4 is fixed between the partitions on both sides of the traction guide rail 44-1, and the traction drive 44-4 contains a winding wire roller of the traction wire rope 44-6 and a motor driving it to rotate. The other end of the traction wire rope 44-6 is connected to the traction connection seat 44-5. The traction connection seat 44-5 is a U-shaped connection rod, and the two sides of the U-shaped are fixed to the traction rolling shaft 44-3 through clamps. The traction drive 44-4 is controlled by the hoisting control box 41 to realize the movement of the traction roller shaft 44-3 and the traction roller 44-2 in the slide groove of the traction guide rail 44-1.

[0037] The method for measuring the drop shock test load of the unmanned helicopter with skid-type landing gear comprises the following steps:

[0038] 1. Arrange the load measurement system 10 and build the ground support system 30 according to the size and space of the unmanned helicopter simulation test piece 20;

[0039] 2. Assemble the unmanned helicopter simulation test piece 20 and adjust the weight, quantity and position of the configuration blocks 25 on the simulated fuselage frame 22 to meet the test index requirements;

[0040] 3. Place the unmanned helicopter simulation test piece 20 on the drop platform 11, and adjust its front, back, left, and right positions to ensure that the lifting suction cup 24 is coaxial with the suspended electromagnet 43;

[0041] 4. Use the lifting control box 41 to control the electromagnet 43 to be energized. After being energized, the electromagnet 43 generates magnetic force to absorb the unmanned helicopter simulation test piece 20 and lift it to a certain height; by adjusting the leveling weight 23-3 of the fuselage center of gravity adjustment device 23 and observing the angle ruler placed on the pitch and roll directions of the simulated fuselage frame 22, the center of gravity of the unmanned helicopter simulation test piece 20 can be fine-tuned to ensure that it is not eccentric when falling.

[0042] 5. Double skid landing test conditions

[0043] After the test preparation is completed, the lifting control box 41 is used to control the electromagnet 43 to be energized. After being energized, the electromagnet 43 generates magnetic force to adsorb the unmanned helicopter simulation test piece 20, and then controls the chain pulley assembly 42 to rise to the required test height;

[0044] After the dynamic acquisition system and the sensor balance are reset and data collection begins, the electromagnet 43 is powered off, and the unmanned helicopter simulation test piece 20 freely falls to the drop platform 11 at the required height, and data collection stops after stabilization;

[0045] 6. Forward flight or sideways flight landing test conditions with speed:

[0046] The lifting control box 41 controls the electric traction device 44 to place the electromagnet 43 and related components directly above the unmanned helicopter simulation test piece 20, and the electromagnet 43 is started to lift the unmanned helicopter simulation test piece 20 by adsorbing the lifting suction cup 24; then the driving motor of the electric traction device 44 is controlled to lift the unmanned helicopter simulation test piece 20 along the slide groove of the traction guide rail 44-1 to the required test height.

[0047] After the test preparation is completed, the dynamic acquisition system and the sensor balance are reset and data collection begins. The control of the electric traction device 44 is stopped. Due to the traction of gravity, the unmanned helicopter simulation test piece 20 slides down along the traction guide rail 44-1. When it slides down the required distance, the electric traction device 44 is started to brake and the electromagnet is disconnected. At this time, due to inertia, the unmanned helicopter simulation test piece 20 still maintains the horizontal or lateral initial velocity of V0 and lands on the drop platform 11. Stop data collection after stabilization;

[0048] Combination Figure 8 The horizontal or lateral initial velocity V0 is determined by the height difference ΔH between the two screws on which the traction guide rail 44-1 is installed, the sliding distance L in the traction guide rail 44-1 and the gravity acceleration g. The specific calculation formula is:

[0049]

[0050] 7. Combination Fig. 9 , by using a dynamic data acquisition instrument to obtain the response values ​​of the load sensor 13 and the acceleration sensor 15 in the drop test. In view of the fact that the signal collected by the sensor when the test piece impacts the drop platform has a high signal-to-noise ratio, it is recommended to use a low-pass filter processing with a frequency less than the base frequency of the drop platform 11 to obtain the processing value of the sensor collection signal. According to the mechanical balance and digital signal processing method, the equivalent impact load in each direction is obtained. The calculation formula is:

[0051]

[0052] Where: M is the mass of the falling platform, g is the weight acceleration constant, a j is the response signal processing value of the jth acceleration sensor in a certain orthogonal direction, F i The response signal processing value of the i-th load sensor in a certain orthogonal direction; if you want to enrich the collection of test process data types, you can choose to configure a high-speed camera to record and a dynamic displacement sensor to be used with a dynamic acquisition instrument to record the displacement history during the test.

[0053] The method proposed in the present invention obtains the dynamic response of the load sensor and acceleration sensor of the unmanned helicopter drop shock test by using a dynamic acquisition system, and obtains its equivalent ground impact load based on mechanical balance and dynamic signal filtering processing methods, thereby solving the problem that the feedback load of the unmanned helicopter landing gear cannot be accurately identified and measured when the landing gear falls to the ground.

[0054] The impact load measuring device has modular components, simple loading and unloading, and small footprint. It is suitable for obtaining ground impact loads in unmanned helicopter skid landing gear drop tests and other product drop tests. The measuring device can be personalized and combined according to the test object, test requirements, and laboratory hardware and software conditions.

[0055] In addition, the invented device can not only complete the traditional double-skid landing test conditions, but also the helicopter-specific side landing and forward landing test conditions with speed that traditional test devices cannot complete, thus filling the gap in such test methods.

Claims

1. A device for measuring the drop shock test load of an unmanned helicopter with a skid-type landing gear, characterized in that: It comprises a load measurement system (10), an unmanned helicopter simulation test piece (20), a ground support system (30) and a lifting control system (40); The lifting control system (40) is arranged on the ground support system (30) and is used to lift the unmanned helicopter simulation test piece (20), complete the double-sled vertical landing and the forward flight or side flight landing with speed of the unmanned helicopter simulation test piece (20), and control the falling height of the unmanned helicopter simulation test piece (20); The load measurement system (10) is arranged on a support platform of a ground support system (30) and is used to collect impact load and acceleration of the unmanned helicopter simulation test piece (20) when it lands; The load measurement system (10) comprises a drop platform (11), a support adapter plate (12), a load sensor (13), and an acceleration sensor (15); The drop platform (11) is connected to the support platform of the ground support system (30) via a support adapter plate (12); an acceleration sensor (15) is provided on the drop platform (11), and a plurality of load sensors (13) are provided around the periphery; The lifting control system (40) comprises a lifting control box (41), a chain pulley assembly (42) and an electromagnet (43); the lifting control box (41) is arranged on a crossbeam of a ground support system (30); the chain pulley assembly (42) is connected to the lifting control box (41); the electromagnet (43) is suspended on a hook of the chain pulley assembly (42); the lifting control box (41) is used to adjust the lifting and lowering of the chain pulley assembly (42) and the on and off of the electromagnet (43); The hoisting control system (40) further comprises an electric traction device (44) for a forward flight landing test or a side flight landing test with speed; the electric traction device (44) comprises a traction guide rail (44-1), a traction roller (44-2), a traction roller shaft (44-3), a traction drive (44-4), a traction connection seat (44-5) and a traction wire rope (44-6); The traction guide rail (44-1) is fixed to the crossbeam of the ground support system (30) through two screw rods; a traction roller shaft (44-3) is rotatably connected to both sides of the traction roller (44-2); the traction roller shaft (44-3) is arranged in a slide groove of the traction guide rail (44-1); the traction roller (44-2) is arranged in the traction guide rail (44-1); the lifting control box (41) is fixed to the lower end of the traction roller shaft (44-3) through a mounting rod; the traction drive (44-4) is fixed to the traction guide rail (44-1); one end of the traction wire rope (44-6) is connected to the traction drive (44-4), and the other end is connected to the traction connecting seat (44-5); the traction connecting seat (44-5) is connected to the traction roller shafts (44-3) on both sides.

2. The drop shock test load measuring device for an unmanned helicopter with a skid-type landing gear according to claim 1 is characterized in that: The unmanned helicopter simulation test piece (20) comprises an unmanned helicopter landing gear (21), a simulated fuselage frame (22), a fuselage center of gravity adjustment device (23), a lifting suction cup (24) and a counterweight (25); The simulated fuselage frame (22) is provided with a counterweight block (25), and the bottom is provided with an unmanned helicopter landing gear (21); the lifting suction cup (24) is fixedly connected to the upper end of the gravity center section cross beam of the simulated fuselage frame (22); the fuselage gravity center adjustment device (23) is composed of four joints (23-1), a round tube rod (23-2) and a leveling weight (23-3) that can move on the round tube rod (23-2); the four corners of the upper end of the simulated fuselage frame (22) are respectively provided with joints (23-1), and four round tube rods (23-2) are connected between the four joints to form a rectangular structure; the gravity center of the unmanned helicopter simulation test piece (20) is finely adjusted by adjusting the positions of the four leveling weights (23-3) on the respective round tube rods (23-2); and the lifting control system (40) is adsorbed with the lifting suction cup (24) in a powered state to lift the unmanned helicopter simulation test piece (20).

3. The drop shock test load measuring device for an unmanned helicopter with a skid-type landing gear according to claim 1, characterized in that: The ground support system (30) comprises a crossbeam (31), a column (32), a support platform (33) and a guide rail (34); two columns (32) are fixed on the support platform (33); and the crossbeam (31) is fixed between the two columns (32).

4. The measuring method of the drop shock test load measuring device of the skid-type landing gear unmanned helicopter according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Arrange the load measurement system (10) and build the ground support system (30); Step 2, assembling the unmanned helicopter simulation test piece (20), adjusting the weight, quantity and position of the counterweight (25) on the simulated fuselage frame (22); Step 3, placing the unmanned helicopter simulation test piece (20) on the drop platform (11), and adjusting its front, back, left, and right positions to ensure that the lifting suction cup (24) and the suspended electromagnet (43) are coaxial; Step 4, using the lifting control box (41) to control the electromagnet (43) to be energized, after which the electromagnet (43) generates magnetic force to absorb the unmanned helicopter simulation test piece (20) and lift it to a certain height; by adjusting the leveling weight (23-3) of the fuselage center of gravity adjustment device (23) and observing the angle ruler placed on the simulated fuselage frame (22) in the pitch and roll directions, the center of gravity of the unmanned helicopter simulation test piece (20) is finely adjusted to ensure that it is not eccentric when falling; Step 5: Conduct a landing test to obtain data collected by the sensor.

5. The measuring method according to claim 4, characterized in that: The landing test includes two landing test conditions: In the double skid landing test condition: The unmanned helicopter simulation test piece (20) is raised to the required test height by controlling the chain pulley assembly (42) through the control of the lifting control box (41); the power supply of the electromagnet (43) is disconnected, and the unmanned helicopter simulation test piece (20) freely falls to the drop platform (11) at the required height, and data collection is stopped after it stabilizes; In forward flight or sideways flight landing test conditions with speed: The lifting control box (41) controls the electric traction device (44) to place the electromagnet (43) directly above the unmanned helicopter simulation test piece (20), and starts the electromagnet (43) to lift the unmanned helicopter simulation test piece (20) by adsorbing the lifting suction cup (24); then the driving motor of the electric traction device (44) is controlled to lift the unmanned helicopter simulation test piece (20) along the slide groove of the traction guide rail (44-1) to the required test height, and the control of the electric traction device (44) is stopped, and the unmanned helicopter simulation test piece (20) slides down along the traction guide rail (44-1). When the required sliding distance is reached, the electric traction device (44) is started to brake, and the power supply of the electromagnet is disconnected at the same time, and the unmanned helicopter simulation test piece (20) falls onto the drop platform (11), and data collection is stopped after stabilization.

6. The measuring method according to claim 4, characterized in that: Also includes calculation of equivalent impact loads A low-pass filter is performed with a frequency lower than the base frequency of the drop platform (11), thereby obtaining a processed value of the sensor acquisition signal; and calculating the equivalent impact load. Where: M is the mass of the falling platform (11), g is the weight acceleration constant, a j is the response signal processing value of the jth acceleration sensor in the orthogonal direction, F i The response signal processing value of the i-th load sensor in the orthogonal direction.

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