Force-displacement measuring platform for testing mass capturing mechanism

Abstract

The invention relates to a force-displacement measuring platform for testing a mass capturing mechanism, and belongs to the technical field of spaceflight. According to the measuring mechanism, a nut is rotationally connected with a supporting seat, the nut is in threaded connection with a lead screw, the nut is connected with a second encoder, and the nut is connected with an adapter shaft; the output end of the motor and the first encoder are connected with the adapter shaft, the motor is connected with the supporting seat, and the motor is connected with the first encoder; the sensor is connected with the supporting seat and is arranged corresponding to the tested piece; and the lead screw is connected with the tested piece and the load mechanism. The disc spring and the screw are designed, so that the influence of different nut pre-tightening forces on the reciprocating motion precision of the capturing mechanism can be explored. The adjusting mode is simple and fast. The reciprocating motion precision of the capturing mechanism under different loads is studied by changing the weight of the balancing weight. The rotation angle of the motor and the rotation angle of the split nut can be measured at the same time, and measurement of the assembly clearance on the reciprocating motion precision of the capturing mechanism is explored.

Description

Technical Field

[0001] This invention relates to a force-displacement measurement platform for testing, belonging to the field of aerospace technology. Background Technology

[0002] Gravitational waves, predicted by Einstein in his 1915 theory of general relativity, are a type of matter wave that offers a new means of detecting celestial activity. Gravitational waves warp spacetime, so they can be detected by measuring changes in distance between objects. However, the spacetime warping caused by gravitational waves is extremely small, making them difficult to measure and detect. In the 1990s, the European Space Agency (ESA) and NASA launched the LISA mission to detect gravitational waves in space. The mission involved emitting lasers from a space-based gravitational wave detector, which were then reflected by a test mass (TM) and received by a receiver. When a gravitational wave passed through the optical path, the light amplified the displacement changes between the test masses caused by the gravitational wave. This change was then detected by the receiver, thus confirming the presence of the gravitational wave.

[0003] Among them, quality verification is the core of a space gravitational wave detection device. Ensuring its high-precision capture and low-disturbance release is of great significance to improving the accuracy of the entire detection system.

[0004] In space-based gravitational wave detection missions, the capture mechanism for the test mass (TM) needs to achieve micrometer-level positioning accuracy and microNewton-level force control to enable high-precision positioning and low-disturbance capture and release. However, its reciprocating motion accuracy is affected by parameters such as the assembly clearance between the motor and the lead screw nut, the measurement accuracy of the mechanism's force-displacement sensors, the load on the mechanism, and the initial preload. These parameters require testing to verify the mechanism and its sensor functionality. Existing testing platforms cannot simultaneously quantify the impact of preload, load, and clearance on dynamic accuracy, resulting in insufficient verification of the on-orbit capture strategy.

[0005] Therefore, there is an urgent need to propose a force-displacement measurement platform for testing mass capture mechanisms to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the aforementioned problems, a force-displacement measurement platform for testing mass capture mechanisms is provided. A brief overview of the invention is given below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0007] The technical solution of the present invention: A force-displacement measurement platform for testing a mass capture mechanism includes: a measuring mechanism connected to a load mechanism; The measuring mechanism includes: a rotatable connection between the lead screw and the support base, a threaded connection between the lead screw and the lead screw, a connection between the lead screw and the second encoder, and a connection between the lead screw and the adapter shaft; The motor's output end, the first encoder, and the adapter shaft are connected; the motor is connected to the support base; and the motor is connected to the first encoder. The sensor is connected to the support base, and the sensor is set to correspond with the measured object. The lead screw is connected to the workpiece being measured and to the load mechanism.

[0008] Preferably, the first encoder is a photoelectric encoder, the second encoder is a magnetic ring encoder, and the sensor is a displacement sensor.

[0009] Preferred: The motor is a servo motor or a hollow shaft ultrasonic motor; The middle part of the adapter shaft is connected to the motor output end via a key, and the right end of the adapter shaft is threadedly connected to the clamping nut, which clamps the key.

[0010] Preferred configuration: The lead screw adopts a two-stage plunger lead screw sleeve, and the lead nut adopts a split nut; the adjustable end cover is detachably connected to the lead screw, the adjustable end cover is detachably connected to the lifting ring, and the lifting ring is connected to the load mechanism.

[0011] Preferably, the support base includes: a motor end support base connected to one end of the lead screw nut via a bearing assembly, a motor end support base connected to a motor bolt, a plunger end support base connected to the other end of the lead screw nut via a bearing assembly, a plunger end support base connected to a sensor, and the plunger end support base having a through hole through which the lead screw passes.

[0012] Preferably, the bearing assembly includes: a motor end support with a stepped hole, and a nut with a stepped shaft shape; the outer ring of one bearing contacts the vertical surface of the stepped hole of the motor end support, the inner ring of one bearing contacts the stepped vertical surface on the left side of the nut, the inner ring of another bearing contacts the stepped vertical surface on the right side of the nut, the bearing end cap is pressed against the outer ring of the other bearing, and screws sequentially pass through the preloaded disc spring, the stepped through hole of the bearing end cap, and the threaded hole of the plunger end support.

[0013] Preferably, the load-bearing mechanism includes a counterweight, a pulley, and a rope, with one end of the rope connected to a lifting ring and the other end of the rope passing over the pulley and connected to the counterweight.

[0014] The present invention has the following beneficial effects: 1) The disc spring and screw designed in this invention can be used to investigate the effect of different nut preload on the reciprocating motion accuracy of the capture mechanism. This adjustment method is simple and quick.

[0015] 2) By changing the weight of the counterweight, the accuracy of the reciprocating motion of the capture mechanism under different loads was studied.

[0016] 3) It can simultaneously measure the motor rotation angle and the split nut rotation angle to explore the effect of assembly clearance on the accuracy of the reciprocating motion of the capture mechanism.

[0017] 4) The performance of the mechanism displacement sensor is verified by comparing the data from the laser displacement sensor with that from the capture mechanism displacement sensor.

[0018] 5) This invention provides a force-displacement measurement platform for inspecting mass capture mechanisms, which features simple structure, high measurement accuracy, simultaneous measurement of multiple parameters, and real-time feedback of measurement results. Attached Figure Description

[0019] Figure 1 This is a structural diagram of a force-displacement measurement platform used for testing mass capture mechanisms.

[0020] Figure 2 It is a cross-sectional view of the measuring mechanism.

[0021] Figure 3 It is an exploded view of the measuring agency. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0023] Specific implementation method one: Combining Figure 1-3 This embodiment describes a force-displacement measurement platform for testing a mass capture mechanism, comprising: a load mechanism and a measuring mechanism, wherein the measuring mechanism 2 is connected to the load mechanism 1; Measuring mechanism 2 includes: such as Figure 2 The components shown are: support base, motor 2-1, first encoder 2-3, adapter shaft 2-4, second encoder 2-8, sensor 2-11, measured component 2-12, lead screw 2-15, and lead nut 2-19. Thread nut 2-19 is rotatably connected to the support base. Thread nut 2-19 is fitted onto the outside of threaded rod 2-15 and threadedly connected to threaded rod 2-15. Thread nut 2-19 is connected to the second encoder 2-8. Figure 2 One end of the middle left side is rigidly connected to the right side of the adapter shaft 2-4 or the output end of the motor 2-1; The output end of motor 2-1 and the first encoder 2-3 are both connected to the adapter shaft 2-4. The outer shell of motor 2-1 is bolted to the support base, and motor 2-1 is bolted to the base of the first encoder 2-3. By comparing the rotation angle and speed between the motor and the nut, the purpose is to investigate the influence of the assembly clearance between motor 2-1 and lead screw 2-19, and between lead screw 2-19 and lead screw 2-15 on the reciprocating motion accuracy of the capture mechanism. Sensor 2-11 is bolted to the support base, and sensor 2-11 is correspondingly set with the measured part 2-12. Motor 2-1 drives the adapter shaft 2-4 and the lead screw nut 2-19 to rotate. Under the limit of the load mechanism, the lead screw 2-15 moves axially to adjust the distance between sensor 2-11 and the measured part 2-12. When the lead screw sleeve moves to a certain position, the measured part 2-12 will squeeze the displacement sensor 2-11. Strain gauges are attached to the sensor. The strain is measured by the strain gauges, which indirectly measures the displacement of the lead screw sleeve. At the same time, a laser displacement sensor is set on the outside of this measurement platform. By comparing the results of the laser displacement sensor and the strain gauge displacement sensor, the performance of the mechanism displacement sensor can be tested. The lead screw 2-15 is bolted to the measured part 2-12, and the lead screw 2-15 is connected to the load mechanism 1. By changing the weight of the counterweight, the influence of different loads on the accuracy of the reciprocating motion mechanism of the capture mechanism can be observed. The mechanism designs the load application position on the lifting ring, which has the advantages of precise and controllable variables and convenient variable control. This invention synchronously quantifies the influence of preload, load, and clearance on dynamic accuracy. The rail capture strategy has been fully verified, and it features simple structure, high measurement accuracy, synchronous measurement of multiple parameters, and real-time feedback of measurement results.

[0024] Specific Implementation Method Two: Combining Figure 1-3This embodiment describes a force-displacement measurement platform for testing a quality capture mechanism. The first encoder 2-3 is a photoelectric encoder, capable of measuring the motor's rotation angle and speed. The other end of the adapter shaft 2-4 passes through the motor 2-1 and is fixedly connected to the code disk of the first encoder 2-3. The base of the first encoder 2-3 has a photoelectric detection component. The second encoder 2-8 is a magnetic ring encoder, capable of measuring the nut's rotation angle and speed. The second encoder 2-8 is fitted onto the outside of the nut 2-19 and is bolted or fixedly connected to the magnetic ring of the second encoder 2-8. The magnetic sensing element of the second encoder 2-8 is fixedly positioned relative to the support base. The encoder reading head 3-4 is bolted to the mounting platform via a bracket, corresponding to the nut but not in contact with it. Specifically, the magnetic ring of the second encoder 2-8 is fixedly connected to the encoder coupling tooling. The encoder coupling fixture is fixed or bolted to the nut 2-19. The sensor 2-11 is a displacement sensor, and the measured part 2-12 is a displacement sensor limiting device. The measured part 2-12 can be a flat metal cylindrical part. It can simultaneously measure the motor rotation angle and the split nut rotation angle to explore the measurement of the reciprocating motion accuracy of the capture mechanism by the assembly gap. This invention can collect data from the displacement sensor of the capture mechanism through photoelectric encoder, magnetic ring encoder, and sensor 2-11, and collect data from the laser displacement sensor through laser sensor. It can test a force-displacement measurement platform used for testing the quality capture mechanism and provide comparative data. By comparing the data of the laser displacement sensor and the displacement sensor of the capture mechanism (sensor 2-11), the performance of the displacement sensor of the mechanism (sensor 2-11) is verified.

[0025] Specific implementation method three: Combining Figure 1-3 This embodiment describes a force-displacement measurement platform for testing a mass capture mechanism. Motor 2-1 is either a servo motor or a hollow shaft ultrasonic motor. The hollow shaft ultrasonic motor improves the compactness of the capture mechanism, eliminates components such as couplings, reduces the complexity of the mechanism, and improves its operational reliability. Measuring mechanism 2 also includes: Figure 2 The encoder mounting plate 2-2, key 2-5, and clamping nut 2-6 are included. The middle part of the adapter shaft 2-4 is connected to the output end of the motor 2-1 via key 2-5. The right end of the adapter shaft 2-4 is threadedly connected to clamping nut 2-6. Clamping nut 2-6 clamps key 2-5. The encoder mounting plate 2-2 is connected to the housing of motor 2-1 and the first encoder 2-3 via bolts.

[0026] Specific implementation method four: Combination Figure 1-3This embodiment describes a force-displacement measurement platform for testing a quality capture mechanism. The lead screw 2-15 uses a two-stage plunger screw sleeve. The through-hole in the shaft of the two-stage plunger screw sleeve serves to avoid the adapter shaft 2-4, providing more space for installation. The nut 2-19 is a split nut; the nut 2-19 includes a threaded upper half 3-2 and a lower half 3-1. The upper half 3-2 is fixedly connected to the encoder coupling fixture 2-9, driving the inner shaft of the magnetic ring encoder 2-8 to rotate. The lead screw and nut structure offers advantages such as easy control and simple structure. This drive scheme reduces the difficulty of mechanism control while also reducing manufacturing costs. The lead screw and nut convert rotational motion into linear motion through helical transmission, utilizing their linear correspondence to achieve high-precision measurement. Measuring mechanism 2 also includes: Figure 2 In the middle, there is an adjustable end cover 2-13 and a lifting ring 2-14; the right end of the lead screw 2-15 has an internal thread, the left side of the adjustable end cover 2-13 has an external thread, the shaft of the adjustable end cover 2-13 has a threaded hole, the adjustable end cover 2-13 is detachably connected to the lead screw 2-15 through the external thread and its mating internal thread, the adjustable end cover 2-13 is detachably connected to the screw of the lifting ring 2-14 on its right side through the threaded hole, and the lifting ring 2-14 is connected to the load mechanism 1.

[0027] Specific Implementation Method Five: Combining Figure 1-3 This embodiment describes a force-displacement measurement platform for testing a mass capture mechanism, the support base of which includes: Figure 2 In the middle, there are motor end support 2-7, plunger end support 2-18 and bearing assembly. The relative positions of motor end support 2-7 and plunger end support 2-18 are fixed. Motor end support 2-7 is fixedly connected to one end of screw nut 2-19 through bearing assembly by interference fit. Motor end support 2-7 is bolted to motor 2-1 on the left. Plunger end support 2-18 is fixedly connected to the other end of screw nut 2-19 through bearing assembly by interference fit. Plunger end support 2-18 is fixedly connected to sensor 2-11. Plunger end support 2-18 has a through hole. Screw 2-15 passes through the through hole but does not contact the through hole. Sensor 2-11 is installed on the left side of the through hole. Measured part 2-12 is installed on screw 2-15 on the right side of the through hole.

[0028] Specific Implementation Method Six: Combination Figure 1-3 This embodiment describes a force-displacement measurement platform for testing a mass capture mechanism, comprising a bearing assembly including: Figure 2 In the middle, there are two bearings 2-10, bearing end caps 2-16, and preloaded disc springs 2-17; The motor end support 2-7 has a stepped hole, and the nut 2-19 has a stepped shaft shape. The outer ring of one bearing 2-10 contacts the vertical surface of the stepped hole of the motor end support 2-7, and the inner ring of one bearing 2-10 contacts the stepped vertical surface on the left side of the nut 2-19. One bearing 2-10 is clamped by the two vertical contact surfaces, and the inner ring of the other bearing 2-10 contacts the stepped vertical surface on the right side of the nut 2-19. The bearing end cover 2-16 presses against the side of the outer ring of the other bearing 2-10, and the other bearing 2-10 is clamped by the vertical contact surface and the left end of the bearing end cover 2-16. Several circumferentially arranged screws sequentially pass through the stepped through holes of the preload disc spring 2-17 and the bearing end cover 2-16 and connect to the corresponding threaded holes of the plunger end support 2-18. The preload disc spring 2-17 is pressed by the vertical surface of the stepped through hole and the nut of the screw. The rotating screws are solid. The disc spring force can be adjusted to regulate the preload and ensure the secure installation of the bearing assembly. This invention utilizes disc spring 2-17 and screws to investigate the influence of different nut preload forces on the reciprocating motion accuracy of the capture mechanism. This adjustment method is simple and quick. By adjusting the compression of disc spring 2-17 with the screw, the preload force applied by bearing end cap 2-16 to the split nut 2-19 and bearing 2-10 (rolling bearing, deep groove ball bearing) is adjusted. The presence of preload force eliminates axial clearance (axial clearance of the bearing, axial clearance when the lead screw and nut are engaged) during operation, ensuring high precision of the mechanism. It also reduces the backlash to some extent, facilitating subsequent motion control. This platform allows for the measurement experiment of the influence of different split nut 2-19 preload forces on the reciprocating motion mechanism of the capture mechanism by adjusting the screw.

[0029] Specific implementation method seven: Combination Figure 1-3 This embodiment describes a force-displacement measurement platform for testing a mass capture mechanism. The load mechanism 1 is a variable load mechanism. By changing the weight of the counterweight, the reciprocating motion accuracy of the capture mechanism under different loads is studied. The platform includes a counterweight 3, a pulley 3-1, and a rope. One end of the rope is fixedly connected to a lifting ring 2-14, and the other end of the rope passes around the pulley 3-1 and is connected to the counterweight 3. The load can be changed by replacing the counterweight 3 with different weights. The pulley is hinged to the pulley bracket, and the pulley bracket and the support seat are bolted to the same mounting platform to fix their relative positions. The counterweight 1-3 of the load mechanism is connected to the lifting ring 2-14 by a pulley and a wire. The lifting ring is fixed by being screwed into the adjustable end cap 2-13. By changing the weight of the counterweight, the effect of different loads on the accuracy of the reciprocating motion mechanism of the capture mechanism can be observed. This mechanism designs the load application position on the lifting ring, which has the advantages of precise and controllable variables and convenient variable control. When the lead screw sleeve moves to a certain position, the limiter will squeeze the displacement sensor. The sensor has a strain gauge attached to it. The strain is measured by the strain gauge, which indirectly measures the displacement of the lead screw sleeve. At the same time, a laser displacement sensor (not shown) is installed on the outside of this measurement platform. By comparing the results of the laser displacement sensor and the strain gauge displacement sensor, the performance of the mechanism's displacement sensor can be tested.

[0030] Example 1: Combination Figure 1-3 As shown, in order to test the displacement of the capture mechanism under different load conditions and bolt preload, and considering compatibility with the capture mechanism, a corresponding force-displacement measurement platform for testing the quality capture mechanism is proposed. Connection Process: Since this invention is for a test platform of the capture mechanism, only the connection process of the measuring mechanism is described, not the connection process of the capture mechanism. First, connect the photoelectric encoder to the motor adapter shaft using pins 3-5. Then, fix the encoder to the encoder mounting plate 2-2 with screws. Remove the hollow shaft ultrasonic motor from the capture mechanism. The other end of the adapter shaft is threaded. Insert the other end of the adapter shaft and the key into the hollow shaft of the ultrasonic motor, and screw in the nut to tighten it. Then, connect the ultrasonic motor to the... The motor end support 2-7 is fixedly connected. Then, the upper half of the split nut 3-5 is fixedly connected to the encoder coupling tool 2-9 with screws. The coupling is then fixedly connected to the magnetic ring encoder 2-8 with screws. The bearing end cover 2-16 is installed on the plunger end support 2-18. Finally, the lifting ring 2-14 is screwed into the adjustable end cover 2-13. The pulley 3-1 is then loosened by the screws and nuts on the back. The position is adjusted so that the upper part of the pulley is on the same horizontal line as the lifting ring 3-2, and then the screws and nuts are tightened. The assembly of the whole machine is completed.

[0031] Working process: This test platform can control two variables for experiments. The rotation of the hollow shaft ultrasonic motor drives the motor adapter shaft to rotate, which in turn drives the split nut to rotate. Through the nut screw mechanism, the secondary plunger screw sleeve moves linearly. When the screw sleeve moves linearly, the displacement sensor limit device squeezes the displacement sensor, converting the displacement into strain, thus measuring the displacement of the capture mechanism. At the same time, a laser displacement sensor is used to measure the displacement and test the performance of the displacement sensor of the capture mechanism. The upper half of the split nut 3-2 is fixed to the encoder coupling tool 2-9, which drives the inner shaft of the magnetic ring encoder 2-8 to rotate, obtaining the rotation angle data of the split nut. The motor adapter shaft is fixed to the inner shaft of the photoelectric encoder 2-3, obtaining the rotation angle data of the ultrasonic motor. The counterweight 3 applies a horizontal force to the capture mechanism through the pulley 3-1 to study the displacement accuracy of the capture mechanism under different loads. The screw of the adjusting disc spring 2-17 can control the preload force on the split nut.

[0032] Among them, the springs include disc springs, and the stiffness can be selected to approximate the required stiffness; if there is no requirement for non-magnetization design, a regular servo motor can be used instead of a hollow shaft ultrasonic motor.

[0033] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A force-displacement measurement platform for testing and inspecting a mass capture mechanism, characterized in that: include: The measuring mechanism (2) is connected to the load mechanism (1); The measuring mechanism (2) includes: a nut (2-19) rotatably connected to a support base, a nut (2-19) threadedly connected to a lead screw (2-15), a nut (2-19) connected to a second encoder (2-8), and a nut (2-19) connected to a transfer shaft (2-4); The output end of the motor (2-1), the first encoder (2-3) and the adapter shaft (2-4) are connected; the motor (2-1) is connected to the support base; and the motor (2-1) is connected to the first encoder (2-3). The sensor (2-11) is connected to the support base, and the sensor (2-11) is set to correspond with the measured part (2-12); The lead screw (2-15) is connected to the test piece (2-12), and the lead screw (2-15) is connected to the load mechanism (1).

2. The force-displacement measurement platform for testing a mass capture mechanism according to claim 1, characterized in that: The first encoder (2-3) is a photoelectric encoder, the second encoder (2-8) is a magnetic ring encoder, and the sensor (2-11) is a displacement sensor.

3. The force-displacement measurement platform for testing a mass capture mechanism according to claim 1, characterized in that: The motor (2-1) is a servo motor or a hollow shaft ultrasonic motor; The middle part of the adapter shaft (2-4) is connected to the output end of the motor (2-1) via a key (2-5), and the right end of the adapter shaft (2-4) is threadedly connected to the clamping nut (2-6).

4. A force-displacement measurement platform for testing a mass capture mechanism according to claim 1 or 3, characterized in that: The lead screw (2-15) adopts a two-stage plunger lead screw sleeve, and the lead nut (2-19) adopts a split nut; The adjustable end cap (2-13) is detachably connected to the lead screw (2-15), the adjustable end cap (2-13) is detachably connected to the lifting ring (2-14), and the lifting ring (2-14) is connected to the load mechanism (1).

5. A force-displacement measurement platform for testing a mass capture mechanism according to claim 4, characterized in that: The support base includes: The motor end support (2-7) is connected to one end of the nut (2-19) through a bearing assembly. The motor end support (2-7) is bolted to the motor (2-1). The plunger end support (2-18) is connected to the other end of the nut (2-19) through a bearing assembly. The plunger end support (2-18) is connected to the sensor (2-11). The plunger end support (2-18) has a through hole through which the lead screw (2-15) passes.

6. A force-displacement measurement platform for testing a mass capture mechanism according to claim 5, characterized in that: The bearing assembly includes: a motor end support (2-7) with a stepped hole, and a nut (2-19) with a stepped shaft shape; the outer ring of one bearing (2-10) contacts the vertical surface of the stepped hole of the motor end support (2-7), the inner ring of one bearing (2-10) contacts the stepped vertical surface on the left side of the nut (2-19), the inner ring of another bearing (2-10) contacts the stepped vertical surface on the right side of the nut (2-19), the bearing end cap (2-16) presses against the side of the outer ring of the other bearing (2-10), and the screws sequentially pass through the stepped through hole of the preloaded disc spring (2-17), the bearing end cap (2-16), and the threaded hole of the plunger end support (2-18).

7. A force-displacement measurement platform for testing a mass capture mechanism according to claim 4, characterized in that: The load mechanism (1) includes: a counterweight (3), a pulley (3-1) and a rope. One end of the rope is connected to a lifting ring (2-14), and the other end of the rope passes around the pulley (3-1) and is connected to the counterweight (3).

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