A controllable horizontal speed scaled drop test method based on pulley balancing method

Abstract

The application discloses a controllable horizontal speed scaled drop test method based on a pulley balance method, and belongs to the technical field of equipment air drop and spacecraft landing. The test system of the application comprises a pulley balance mechanism, an electromagnetic releaser, a scaled model, counterweight weights and a horizontal conveying belt. The pulley balance mechanism comprises a pulley set, connecting ropes, a test suspension frame and the counterweight weights. The pulley set is fixed to the top of the test suspension frame. The connecting ropes pass through the pulley set, one end of the connecting ropes is connected with the scaled model, and the other end of the connecting ropes is connected with the counterweight weights. The electromagnetic releaser is arranged at the weight end of the pulley balance mechanism, and the horizontal conveying belt is additionally arranged at the scaled model end. Through the regulation of the speed of the horizontal conveying belt, the scaled drop test under the condition of the equivalent simulation of gravitational acceleration and the coupling of horizontal speed is realized.

Description

Technical Field

[0001] This invention belongs to the field of equipment airdrop and spacecraft landing technology, specifically a controllable horizontal velocity scaled drop test method based on pulley balancing. Background Technology

[0002] In the field of equipment airdrop and spacecraft landing technology, the drop performance of equipment and spacecraft is a crucial indicator determining their safety and reliability during service. It requires thorough experimental verification to ensure they meet design requirements. However, airdropped equipment is generally large and heavy, necessitating the construction of large test sites for full-scale prototype drop tests. This leads to high costs, long prototype manufacturing cycles, and difficulties in repeating the tests. Therefore, scaled-down model testing is an important verification method in this field. For scaled-down tests, the principle of similarity must be strictly followed. Besides the proportional reduction in the geometric dimensions and mass of the scaled-down model, the gravitational acceleration must also be proportionally scaled down to ensure the test results accurately reflect the prototype's actual drop response. Currently, mainstream methods for simulating gravitational acceleration in scaled-down models include centrifugal loading, aerodynamic suspension, pulley balancing, and ramp simulation. The pulley balancing method uses the mechanical balance of pulleys and counterweights to offset part of the gravity of the scaled-down model, achieving an equivalent gravitational acceleration environment after scaling. Due to its advantages such as simple principle, simple structure and low manufacturing cost, it has been widely used in scaled-down model drop tests.

[0003] Traditional pulley balancing methods, to ensure the stability of their mechanical equilibrium system, require the scaled-down model to maintain a strictly vertical motion attitude during the drop test. Once the scaled-down model acquires horizontal velocity, an additional horizontal force is generated between the pulley system and the model, disrupting the equilibrium state of the equivalent gravitational acceleration. Therefore, traditional pulley balancing methods can only simulate vertical landing velocities. However, in practical engineering applications, whether it's airdropped equipment or landing spacecraft, the actual drop test is not merely a vertical descent; it often involves a certain horizontal velocity. The coupling effect of horizontal velocity and vertical descent motion affects the buffering energy absorption and reliability performance, thus requiring accurate simulation in experimental setups. To address this, there is an urgent need to propose a method for simulating scaled-down drop tests with controllable horizontal velocity, based on the equivalent gravity simulation of the pulley balancing method. Summary of the Invention

[0004] The purpose of this invention is to provide a test method based on the traditional pulley balancing method, which simultaneously simulates the coupled working condition of horizontal velocity during drop testing. This method adds a horizontal conveyor belt below the drop test area. Based on the principle of relative motion, by adjusting the speed and direction of the conveyor belt, it equivalently simulates the working condition of a scaled-down prototype with horizontal velocity during drop testing. This satisfies the requirement of simulating coupled working conditions with horizontal velocity during drop testing based on the traditional pulley balancing method, thereby improving the accuracy and applicability of scaled-down drop testing.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] A controllable horizontal velocity scaled-down drop test method based on pulley balancing is mainly achieved by setting an electromagnetic release device below the counterweight, and adding a horizontal conveyor belt below the scaled-down prototype and the buffer airbag. By adjusting the drive device of the horizontal conveyor belt, the speed and direction of the horizontal conveyor belt are changed, thereby realizing a scaled-down drop test under the coupled condition of equivalent simulation of gravity acceleration and horizontal velocity.

[0007] Furthermore, the experimental system of the present invention includes a horizontal conveyor belt drive device, a horizontal conveyor belt, a buffer airbag, a scaled-down prototype, a test suspension frame, a pulley block, a test support frame, a connecting rope, a counterweight, an electromagnetic release device, and a horizontal conveyor belt support frame. The pulley block is fixed to both ends of the test suspension frame. The connecting rope passes around the pulley block, with one end connected to the scaled-down prototype and the other end connected to the counterweight. The buffer airbag is attached directly below the scaled-down prototype. The electromagnetic release device uses an electromagnet. When the scaled-down prototype and the buffer airbag are raised to the designed height, the electromagnetic release device is positioned directly below the counterweight, with the electromagnet's adsorption end facing upwards so that it attracts the lower surface of the counterweight.

[0008] Furthermore, the horizontal conveyor belt described in this invention includes a horizontal conveyor belt drive device and a horizontal conveyor belt support frame. The speed of the horizontal conveyor belt is controlled by the horizontal conveyor belt drive device, and then it is laid directly below the scaled-down prototype. The test system strictly adheres to the principle of similarity, therefore the gravitational acceleration needs to be scaled down according to a certain ratio. At this time, the mass of the counterweight is usually less than the mass of the scaled-down prototype. The force difference caused by the mass difference is compensated by the electromagnetic attraction force generated by the electromagnet in the electromagnetic release device after it is energized, thereby ensuring that the scaled-down prototype is stably suspended at both ends of the test suspension frame before the drop test.

[0009] Furthermore, the horizontal conveyor belt described in this invention is adjusted to a preset horizontal speed via a horizontal conveyor belt drive setting. For ground conditions requiring earthquake resistance, the conveyor belt can be modified for installation to achieve the most accurate simulation of the earthquake environment. The pulley balance suspension mechanism suspends the scaled-down model to a preset height. After the model stabilizes and the horizontal conveyor belt's operating state stabilizes, the electromagnet current is cut off, the electromagnetic attraction force disappears, and the scaled-down prototype falls vertically with equivalent acceleration, eventually contacting the horizontal conveyor belt. This achieves an equivalent simulation of the earthquake test under the coupled vertical fall and horizontal speed conditions.

[0010] The advantages of this invention compared to the prior art are as follows:

[0011] This invention achieves accurate equivalent simulation of gravitational acceleration by combining the electromagnetic attraction force generated by the electromagnet in the counterweight 9 and the electromagnetic release device 10. This solves the problem that the traditional pulley balancing method cannot accurately match the equivalent gravitational acceleration by relying solely on the weight of the counterweight. The electromagnetic attraction force can be precisely controlled to adapt to the prototype test requirements of different scale ratios, thereby improving the accuracy and applicability of the equivalent gravity simulation.

[0012] In addition, by controlling the energizing current of the electromagnetic release device, the electromagnetic attraction force can be precisely controlled and adjusted. Since the electromagnet has a fast on / off response speed, the delay or jamming problem of the mechanical release mechanism can be avoided, ensuring that the scaled-down prototype falls on time after the horizontal conveyor belt speed stabilizes, thus ensuring the synchronization and stability of the simulated vertical fall and horizontal speed coupling conditions.

[0013] By adjusting the horizontal conveyor belt drive, the speed and direction of the horizontal conveyor belt can be controlled, thus adapting to various testing requirements for horizontal speed conditions. This testing method, through precise gravity equivalent simulation and horizontal speed control, effectively avoids the interference of horizontal motion on the gravity balance system found in traditional methods. The testing process is stable and controllable, and the obtained drop performance parameters are closer to the actual operating conditions of the prototype, effectively improving the accuracy and applicability of the testing system. Attached Figure Description

[0014] Figure 1 shows a controllable horizontal velocity scaled-down drop test system based on the pulley balancing method in an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of a controllable horizontal conveyor belt in an embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of a simulated prototype and a buffer airbag example in an embodiment of the present invention;

[0017] Among them, 1-horizontal conveyor belt drive device, 2-horizontal conveyor belt, 3-buffer airbag, 4-scale prototype, 5-test suspension frame, 6-pulley block, 7-test support frame, 8-connecting rope, 9-counterweight, 10-electromagnetic release device, 11-horizontal conveyor belt support frame. Detailed Implementation

[0018] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0019] This example provides a controlled horizontal velocity scaled-down drop test based on the pulley balancing method, such as... Figures 1-3 As shown, the scaled-down drop test system of the present invention consists of, from left to right, a horizontal conveyor belt drive device 1, which is installed in a horizontal conveyor belt support frame 11. A horizontal conveyor belt 2 is fitted onto the horizontal conveyor belt support frame 11. A buffer airbag 3 is attached directly below the scaled-down prototype 4. A test suspension frame 5 is connected to a pulley block 6 and simultaneously connected to a height-adjustable test support frame 7 to adjust the suspension height. One end of a connecting rope 8 is connected to the scaled-down prototype 4, and the other end is connected to a counterweight 9. An electromagnetic release device 10 is installed below the counterweight 9.

[0020] Before the scaled-down drop test begins, the relevant parameters are set according to the test conditions. The counterweight 9 and the scaled-down prototype 4 are in mechanical equilibrium and are connected by the connecting rope 8. The required mass of the counterweight 9 is calculated based on the equivalent gravitational acceleration value. Generally, the equivalent gravitational acceleration in the scaled-down test is less than the Earth's gravitational acceleration, so the mass of the counterweight is usually less than the mass of the scaled-down prototype 4. Therefore, there is a mass difference between the scaled-down prototype 4 and the counterweight 9, which creates a gravity difference. This gravity difference is compensated by the attraction force generated by the electromagnet on the electromagnetic release device 10. The magnitude of the electromagnet current is obtained by combining the electromagnetic force coefficient of the electromagnet. According to the test condition design requirements, the scaled-down prototype 4 and the buffer airbag 3 are raised to the initial design height.

[0021] After determining the above parameters based on the experimental design conditions, the counterweight 9 is adjusted to the corresponding equivalent mass. The buffer airbag 3 is attached directly below the scaled-down prototype 4. The pulley block 6 is connected to both ends of the experimental suspension frame 5, and the connecting rope 8 is passed through the pulley block 6. One end of the connecting rope 8 is connected to the counterweight 9, and the other end is connected to the scaled-down prototype 4. The experimental support frame 7 is connected to the experimental suspension frame 5. After all preparations are completed, the height of the experimental support frame 7 is adjusted to drive the experimental suspension frame 5 to suspend the scaled-down prototype 4 and the buffer airbag 3 to the set initial height. A set current is supplied to the electromagnet in the electromagnetic release device 10 to construct an equivalent gravity balance environment. Then, according to the designed experimental conditions, the horizontal conveyor belt drive device 1 is activated, and the movement direction of the horizontal conveyor belt 2 is set in the opposite direction according to the principle of relative motion to realize the simulation of horizontal speed.

[0022] After the horizontal conveyor belt 2 stabilizes, the current to the electromagnet in the electromagnetic release device 10 is cut off, causing the electromagnetic attraction force to disappear and the pulley balance system to be disrupted. The scaled-down prototype 4 then falls vertically under the equivalent gravitational acceleration, performing a drop test. The acceleration of the scaled-down prototype during the drop test is measured using pre-set measuring equipment, and the horizontal conveyor belt 2 is shut off in a timely manner to conclude the test. If repeated verification is required for different landing speeds or landing surface environments, the corresponding parameters are changed, such as the mass of the counterweight, the suspension height of the scaled-down prototype, the magnitude and direction of the horizontal speed of the horizontal conveyor belt, and the surface material of the horizontal conveyor belt. The above steps are repeated to conduct the test again. If no modification or repeated verification is required, the test ends.

[0023] This experimental system, through adjustments to the controllable electromagnetic release device 10 and the counterweight 9, can accurately simulate different equivalent gravitational accelerations. It can also simulate different horizontal velocities via a controllable horizontal conveyor belt 2, and simulate different landing surface environments by attaching different materials to the surface of the conveyor belt 2. Therefore, this experimental system can achieve equivalent simulation tests of coupled vertical fall and horizontal velocity conditions, effectively avoiding the influence of traditional pulley balancing methods when simulating horizontal velocity, and improving the accuracy and applicability of the experimental system.

[0024] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A controlled horizontal velocity scaled-down drop test method based on pulley balancing, characterized in that, The method employs a test system, which includes a horizontal conveyor belt drive device (1), a horizontal conveyor belt (2), a buffer airbag (3), a scaled-down prototype (4), a test suspension frame (5), a pulley block (6), a test support frame (7), a connecting rope (8), a counterweight (9), an electromagnetic release device (10), and a horizontal conveyor belt support frame (11). The pulley assembly (6) is fixed to the top of the test suspension frame (5), the connecting rope (8) passes around the pulley assembly (6), one end of the connecting rope (8) is connected to the scaled-down prototype (4), the other end of the connecting rope (8) is connected to the counterweight (9), and a buffer airbag (3) is attached directly below the scaled-down prototype (4). An electromagnetic release device (10) is set below the counterweight (9), and a horizontal conveyor belt (2) is added below the scaled prototype (4). The horizontal conveyor belt (2) is fitted onto the horizontal conveyor belt support frame (11), which contains a horizontal conveyor belt drive device (1). The running speed of the horizontal conveyor belt (2) is controlled by adjusting the horizontal conveyor belt drive device (1), thereby realizing the scaled drop test under the condition of equivalent simulation of gravity acceleration and horizontal velocity coupling.

2. The controlled horizontal velocity scaled drop test method based on pulley balancing method according to claim 1, characterized in that, The test suspension frame (5) is connected to the height-adjustable test support frame (7) to achieve the adjustment of the suspension height.

3. The controlled horizontal velocity scaled drop test method based on pulley balancing method according to claim 1, characterized in that, The electromagnetic release device (10) uses an electromagnet. When the scaled-down prototype (4) and the buffer airbag (3) are raised to the designed height, the electromagnetic release device (10) is placed directly below the counterweight (9). The electromagnet in the electromagnetic release device (10) is set with its adsorption end facing upward so that it can be adsorbed with the lower end face of the counterweight.

4. The controlled horizontal velocity scaled-down drop test method based on pulley balancing method according to claim 1, characterized in that, The horizontal conveyor belt (2) includes a speed control drive to make the speed of the horizontal conveyor belt adjustable and is laid directly below the scale model. The horizontal conveyor belt (2) is set with a preset horizontal speed through the speed control drive. The speed can be modified on the conveyor belt to meet the requirements of the earthquake ground environment, so as to achieve the most accurate simulation of the earthquake environment.

5. The controlled horizontal velocity scaled-down drop test method based on pulley balancing method according to claim 1, characterized in that, The test system is strictly based on the principle of similarity. Therefore, the gravitational acceleration needs to be scaled down according to a certain ratio. At this time, the mass of the counterweight is usually less than the mass of the scaled-down prototype. The force difference caused by the mass difference between the two is compensated by the electromagnetic adsorption force generated after the electromagnet is energized, so as to realize that the scaled-down prototype is stably suspended on the test suspension frame (5) before the drop.

6. The controlled horizontal velocity scaled-down drop test method based on pulley balancing method according to claim 1, characterized in that, The height of the test support frame (7) is adjustable, which drives the test suspension frame (5) to lift the scaled prototype (4) and the buffer airbag (3) attached to the bottom of the scaled prototype (4) to a preset height. After the horizontal conveyor belt is running stably, the current of the electromagnetic release device (10) is cut off, the electromagnetic adsorption force disappears, and the scaled prototype (4) and the buffer airbag (3) fall vertically according to the equivalent acceleration and finally contact the horizontal conveyor belt, realizing the equivalent simulation of the vertical drop and horizontal velocity coupling condition of the drop test.

7. The controlled horizontal velocity scaled drop test method based on pulley balancing method according to claim 1, characterized in that, The test system can accurately simulate different equivalent gravitational accelerations by adjusting the electromagnetic release device (10) with controllable electromagnetic force and the counterweight (9); it can simulate different horizontal speeds by changing the speed and direction of the horizontal conveyor belt (2), and it can simulate different landing surface environments by attaching different materials to the surface of the horizontal conveyor belt (2).

8. The controlled horizontal velocity scaled-down drop test method based on pulley balancing method according to claim 1, characterized in that, Before the scaled drop test begins, the corresponding parameters need to be set so that the counterweight (9) and the scaled prototype (4) are in mechanical equilibrium. The mass of the required counterweight (9) is calculated by combining the force of the connecting rope (8) with the equivalent gravitational acceleration value. Due to the mass difference between the scaled-down prototype (4) and the counterweight (9), a gravity difference is formed at both ends of the pulley system. This gravity difference is compensated by the electromagnetic attraction force generated by the electromagnet in the electromagnetic release device (10). The magnitude of the electromagnet current is obtained by combining the electromagnetic force coefficient of the electromagnet. According to the design requirements of the test conditions, the scaled-down prototype (4) and the buffer airbag (3) are raised to the initial height designed.

9. A controlled horizontal velocity scaled-down drop test method based on pulley balancing method according to claim 8, characterized in that, After determining the parameters according to the experimental design conditions, the counterweight (9) is adjusted to the equivalent mass. The scaled prototype (4) and the buffer airbag (3) are suspended to the set initial height through the test suspension frame (5). The set current is passed to the electromagnet to construct an equivalent gravity balance environment. Then, the horizontal conveyor belt drive device (1) is turned on according to the designed experimental conditions. The conveyor motion direction is set in the opposite direction according to the principle of relative motion to realize the horizontal speed simulation. After the conveyor belt speed stabilizes, the electromagnet is cut off, so that the electromagnetic attraction force disappears and the pulley balance system is destroyed. The scaled prototype (4) falls vertically under the action of equivalent gravity acceleration to perform the drop test. The acceleration of the scaled prototype (4) during the drop test is measured by the preset measuring equipment, and the horizontal conveyor belt (2) is turned off in time to finish the test. If it is necessary to repeat the verification for different landing speeds or landing surface environments, the corresponding parameters are changed and the above steps are repeated to carry out the test. If no repeated verification is required, the test ends.

10. A controlled horizontal velocity scaled-down drop test method based on pulley balancing method according to claim 9, characterized in that, The parameters include the mass of the counterweight, the suspension height of the scaled-down prototype, the horizontal speed and direction of the horizontal conveyor belt, and the surface material of the horizontal conveyor belt.

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