Constant-tension suspension device based on rotary zero-stiffness mechanism

Abstract

The invention provides a constant-tension suspension device based on a rotary zero-stiffness mechanism, which comprises a magnetic negative-stiffness structure, a spring positive-stiffness structure, a winding structure and a control structure, the winding structure is used for suspending an unloading target, the magnetic negative stiffness structure and the spring positive stiffness structure are both located in the winding structure, and the magnetic negative stiffness structure and the spring positive stiffness structure are combined with the winding structure to achieve constant torque output; the spring positive stiffness structure comprises a torsional spring; the control structure is connected with the winding structure and used for adjusting and controlling the winding structure. According to the constant-tension suspension device based on the rotary zero-stiffness mechanism, ground simulation equipment technical support is provided for researchers to study the operation reliability of a spacecraft in the space environment, the overall structure is stable, high unloading precision can be achieved, long-time stable operation can be conducted, and reliability is high.

Description

Technical Field

[0001] The invention belongs to the technical field of ground micro-low gravity simulation, and in particular relates to a constant tension suspension device based on a rotary zero-rigidity mechanism. Background Art

[0002] Due to the high reliability of space missions, microgravity simulation must be performed on the spacecraft's space actuators on the ground before executing space missions to verify their motion reliability in a micro-low gravity environment. The constant tension suspension device based on a rotary zero-stiffness mechanism is a microgravity simulation device used to verify the motion of a spacecraft in a weightless state, and is mainly used to unload the gravity exerted on the spacecraft during its motion.

[0003] At present, the constant force output of constant force suspension is lagging and unstable. Moreover, traditional equipment has sensors, springs and other units connected in series in the suspension rope, which will produce additional inertia and affect the unloading accuracy. Summary of the invention

[0004] In view of this, the present invention aims to propose a constant tension suspension device based on a rotary zero-stiffness mechanism to solve the problems of constant force output lag and instability in constant force suspension. Moreover, traditional equipment has sensors, springs and other units connected in series in the suspension rope, which will generate additional inertia and affect the unloading accuracy.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows: The present invention provides a constant tension suspension device based on a rotary zero-stiffness mechanism, comprising a magnetic negative stiffness structure, a spring positive stiffness structure, a winch structure, and a control structure; the winch structure is used to suspend an unloading target, the magnetic negative stiffness structure and the spring positive stiffness structure are both located inside the winch structure, and the two are combined with the winch structure to achieve constant torque output; the spring positive stiffness structure comprises a torsion spring; the control structure is connected to the winch structure, and is used to adjust and control the winch structure.

[0006] Furthermore, the magnetic negative stiffness structure is distributed in the form of inner and outer rings and is divided into an inner ring magnet and an outer ring magnet. The inner ring magnet is fixedly connected to the rotating shaft, and the outer ring magnet is fixed to the reel.

[0007] Furthermore, the inner ring magnets and the outer ring magnets each include four groups of magnets, each group of magnets is composed of two magnets with opposite magnetization directions, the inner and outer magnets interact with each other in the air gap therebetween to generate magnetic force, and when the axes of the inner and outer magnets are aligned, the generated interaction forces cancel each other out in the tangential direction, and the resultant force is 0.

[0008] Furthermore, the torsion spring is wound around the rotating shaft, both ends of the torsion spring are fixedly connected to the rotating shaft, and the middle part of the torsion spring is fixedly connected to the reel.

[0009] Furthermore, the stiffness coefficient of the torsion spring and the stiffness coefficient of the magnetic negative stiffness structure under force rotation are equal in magnitude and opposite in direction.

[0010] Furthermore, the stiffness coefficient is the ratio of the rotation angle after the relative position of the inner ring magnet and the outer ring magnet is changed when the target is hung at the end of the rope to the repulsive force generated between the magnets in the tangential direction of the circle at this time.

[0011] Furthermore, the winch structure includes a motor, a reducer, a bearing seat, a drum, an adapter shaft, a rotating shaft, an external adapter shaft, and a rope. The output shaft of the motor is connected to the input port of the reducer, the output shaft of the reducer is connected to the adapter shaft, the adapter shaft is rotatably connected to the bearing seat, the adapter shaft is fixedly connected to the rotating shaft, the external adapter shaft is fixedly connected to the rotating shaft, the external adapter shaft is rotatably connected to the bearing seat, and a rope for hanging the unloading target is wound around the drum.

[0012] Furthermore, the control structure includes a circular grating, a reading head, and a controller. The circular grating is fixed on the end face of the reel, the reading head is fixed on the rotating shaft, and the controller is connected to the motor, the circular grating, and the reading head.

[0013] Compared with the prior art, the constant tension suspension device based on the rotary zero stiffness mechanism described in the present invention has the following advantages: (1) The present invention provides ground simulation equipment technical support for researchers to study the reliability of spacecraft operation in space environment.

[0014] (2) The present invention realizes constant torque output in a small angle range through torsion springs, magnets, reducers and motors, etc., which makes up for the problem of constant force output lag and instability in the current constant force suspension, and then realizes large-scale constant tension suspension for targets with large mass through active control of the motor.

[0015] (3) The present invention integrates the constant force unit into the hoisting mechanism, which solves the problem that the traditional equipment, in which sensors, springs and other units are connected in series in the suspension rope, will generate additional inertia and affect the unloading accuracy.

[0016] (4) The overall structure of the present invention is stable, and the motion system can achieve high unloading accuracy through stable connection, and can operate stably for a long time with high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] In the attached picture: Figure 1It is a schematic diagram of the internal axle side of the constant tension suspension device based on the rotary zero-stiffness mechanism according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the internal structure of the constant tension suspension device based on the rotary zero stiffness mechanism according to an embodiment of the present invention; Figure 3 It is a schematic diagram of the distribution of magnetic negative stiffness structure in the constant tension suspension device based on the rotary zero stiffness mechanism according to an embodiment of the present invention; Figure 4 It is a line graph of the test values ​​of the magnet applied force and the rotation angle in the constant tension suspension device based on the rotary zero stiffness mechanism according to the embodiment of the present invention.

[0019] Description of reference numerals: 1. Motor; 2. Reducer; 3. Bearing seat; 4. Reading head; 5. Circular grating; 6. Reel; 7. Adapter shaft; 8. Rotating shaft; 9. Torsion spring; 10. Inner ring magnet; 11. Outer ring magnet; 12. Outer adapter shaft; 13. Rope; 14. Unloading target. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0023] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0024] See also Figure 1-Figure 4 As shown, Figure 3 The magnets with opposite magnetization directions in the inner circle and the outer circle are distinguished by different symbols inside the magnets.

[0025] The present embodiment provides a constant tension suspension device based on a rotary zero-stiffness mechanism, comprising a magnetic negative stiffness structure, a spring positive stiffness structure, a winch structure, and a control structure; the winch structure is used to suspend an unloading target 14, and the magnetic negative stiffness structure and the spring positive stiffness structure are both located inside the winch structure, and the two are combined with the winch structure to achieve a constant torque output; the spring positive stiffness structure comprises a torsion spring 9; the control structure is connected to the winch structure, and is used to adjust and control the winch structure.

[0026] Specifically, in this embodiment, the magnetic negative stiffness structure is distributed in two inner and outer rings and is divided into an inner ring magnet 10 and an outer ring magnet 11 . The inner ring magnet 10 is fixedly connected to the rotating shaft 8 , and the outer ring magnet 11 is fixed to the reel 6 .

[0027] Specifically, in this embodiment, the inner ring magnet 10 and the outer ring magnet 11 each include four groups of magnets, each group of magnets is composed of two magnets with opposite magnetization directions, and the inner and outer magnets interact with each other in the air gap therebetween to generate magnetic force. When the axes of the inner and outer magnets are aligned, the interaction forces generated cancel each other out in the tangential direction, and the resultant force is 0.

[0028] Specifically, in this embodiment, the torsion spring 9 is wound around the rotating shaft 8 , both ends of the torsion spring 9 are fixedly connected to the rotating shaft 8 , and the middle portion of the torsion spring 9 is fixedly connected to the reel 6 .

[0029] Specifically, in this embodiment, the stiffness coefficient of the torsion spring 9 is equal in magnitude to the stiffness coefficient of the magnetic negative stiffness structure when it is subjected to force rotation, but in the opposite direction.

[0030] Specifically, in this embodiment, the stiffness coefficient is the ratio of the rotation angle after the relative position of the inner ring magnet 10 and the outer ring magnet 11 is changed when the unloading target 14 is hung at the end of the rope 13 to the repulsive force generated between the magnets in the circumferential tangential direction at this time.

[0031] Specifically, in this embodiment, the winch structure includes a motor 1, a reducer 2, a bearing seat 3, a drum 6, an adapter shaft 7, a rotating shaft 8, an outer adapter shaft 12, and a rope 13. The output shaft of the motor 1 is connected to the input port of the reducer 2, the output shaft of the reducer 2 is connected to the adapter shaft 7, the adapter shaft 7 is rotatably connected to the bearing seat 3, the adapter shaft 7 is fixedly connected to the rotating shaft 8, the outer adapter shaft 12 is fixedly connected to the rotating shaft 8, the outer adapter shaft 12 is rotatably connected to the bearing seat 3, and a rope 13 for hanging an unloading target 14 is wound around the drum 6.

[0032] This embodiment achieves constant torque output in a small angle range through torsion springs, magnets, reducers and motors, etc., which makes up for the current constant force suspension constant force output lag and instability. Then, through the active control of the motor, a large-scale constant tension suspension of a target with a large mass can be achieved.

[0033] This embodiment divides the constant tension suspension device into a magnetic negative stiffness structure, a hoisting structure, and a control structure. The constant tension suspension device is integrated in the hoisting mechanism, which solves the problem that traditional equipment has additional inertia caused by connecting sensors, springs and other units in series in the suspension rope, affecting the unloading accuracy.

[0034] Specifically, in this embodiment, the control structure includes a circular grating 5, a reading head 4, and a controller. The circular grating 5 is fixed at the end face of the reel 6, the reading head 4 is fixed on the rotating shaft 8, and the controller is connected to the motor 1, the circular grating 5, and the reading head 4.

[0035] Working principle of the embodiment: A small range of constant torque output is achieved through the interaction between the magnet and the torsion spring, and a large range of following state is achieved through the active control of the rope winding by the motor. When the unloading target 14 is suspended under the rope 13, the torsion spring 9 is pulled to deform, and the torsion spring 9 generates a reverse torque applied to the drum 6 to ensure that the rope 13 has a constant tension.

[0036] The relative positions of the inner ring magnet 10 and the outer ring magnet 11 are as follows: Figure 3 As shown. When the constant tension suspension device suspends the unloading target 14, the relative position of the inner ring magnet 10 and the outer ring magnet 11 changes slightly at the same time as the torsion spring 9 is deformed. According to the principle that like magnets repel each other, a repulsive force will be generated between the magnets in the tangential direction of the circle. The magnitude of the repulsive force is proportional to the rotation angle, and the ratio of the repulsive force to the rotation angle is regarded as the stiffness coefficient being equal to the stiffness coefficient of the torsion spring 9, but opposite in direction.

[0037] The proportional relationship here is Figure 4 As shown, Figure 4 The following is a line graph of the test values ​​of the magnet applied force and the rotation angle. After calculation, it is found that the ratio of the repulsive force to the rotation angle is about -0.04Nm / °.

[0038] Table 1 Torsion spring force 3 Nm 4 Nm Test 1 rotation angle 65.6664 88.866 Test 2 rotation angle 64.665 87.827 Table 1 is a data record table for the torsion spring force test. The torsion spring stiffness coefficient of test 1 is calculated to be (4-3) / (88.866-65.6664)≈0.04Nm / °; the torsion spring stiffness coefficient of test 2 is calculated to be (4-3) / (87.827-64.665)≈0.04Nm / °, which verifies the correctness of the ratio of the magnet repulsion force to the rotation angle being equal in magnitude and opposite in direction to the torsion spring stiffness coefficient.

[0039] At this time, the constant force output of the constant tension suspension device can be achieved within the range of ±5°, that is, the tension does not increase with the movement of the object. The relative rotation angle can be measured by the circular grating 5 and the reading head 4, and then the motor 1 controls the rotating shaft 8 to shorten the relative rotation angle between the magnets so that the relative rotation angle between the magnets does not change over a large range. When the object is subjected to external force, it can be subjected to a constant tension while moving vertically over a large range.

[0040] This embodiment provides ground simulation equipment technical support for researchers to study the reliability of spacecraft operation in space environment. The overall structure is stable, and the motion system can achieve high unloading accuracy through stable connection, and can operate stably for a long time with high reliability.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A constant tension suspension device based on a rotary zero stiffness mechanism, characterized in that: include, A magnetic negative stiffness structure, a spring positive stiffness structure, a hoisting structure, and a control structure; the hoisting structure is used to suspend and unload a target (14); the magnetic negative stiffness structure and the spring positive stiffness structure are both located inside the hoisting structure, and the two are combined with the hoisting structure to achieve a constant torque output; the spring positive stiffness structure comprises a torsion spring (9); the control structure is connected to the hoisting structure and is used to adjust and control the hoisting structure.

2. The constant tension suspension device based on the rotary zero stiffness mechanism according to claim 1, characterized in that: The magnetic negative stiffness structure is distributed in an inner and outer ring shape and is divided into an inner ring magnet (10) and an outer ring magnet (11). The inner ring magnet (10) is fixedly connected to the rotating shaft (8), and the outer ring magnet (11) is fixed to the reel (6).

3. The constant tension suspension device based on the rotary zero stiffness mechanism according to claim 2, characterized in that: The inner ring magnets (10) and the outer ring magnets (11) each include four groups of magnets, each group of magnets is composed of two magnets with opposite magnetization directions, the inner and outer magnets interact with each other in the air gap between them to generate magnetic force, and when the axes of the inner and outer magnets are aligned, the generated interaction forces cancel each other out in the tangential direction, and the resultant force is 0.

4. The constant tension suspension device based on the rotary zero stiffness mechanism according to claim 3, characterized in that: The torsion spring (9) is wound around the rotating shaft (8), the two ends of the torsion spring (9) are fixedly connected to the rotating shaft (8), and the middle part of the torsion spring (9) is fixedly connected to the winding drum (6).

5. The constant tension suspension device based on the rotary zero stiffness mechanism according to claim 4, characterized in that: The stiffness coefficient of the torsion spring (9) is equal in magnitude to the stiffness coefficient of the magnetic negative stiffness structure when it is subjected to force rotation, but in the opposite direction.

6. The constant tension suspension device based on the rotary zero stiffness mechanism according to claim 5, characterized in that: The stiffness coefficient is the ratio of the rotation angle after the relative position of the inner ring magnet (10) and the outer ring magnet (11) is changed when the unloading target (14) is hung at the end of the rope (13) and the repulsive force generated between the magnets in the tangential direction of the circle at this time.

7. The constant tension suspension device based on a rotary zero stiffness mechanism according to claim 6, characterized in that: The hoisting structure comprises a motor (1), a reducer (2), a bearing seat (3), a drum (6), a transfer shaft (7), a rotary shaft (8), an outer transfer shaft (12), and a rope (13). The output shaft of the motor (1) is connected to the input port of the reducer (2), the output shaft of the reducer (2) is connected to the transfer shaft (7), the transfer shaft (7) is rotatably connected to the bearing seat (3), the transfer shaft (7) is fixedly connected to the rotary shaft (8), the outer transfer shaft (12) is fixedly connected to the rotary shaft (8), the outer transfer shaft (12) is rotatably connected to the bearing seat (3), and a rope (13) for hanging an unloading target (14) is wound around the drum (6).

8. The constant tension suspension device based on a rotary zero stiffness mechanism according to claim 7, characterized in that: The control structure comprises a circular grating (5), a reading head (4), and a controller. The circular grating (5) is fixed on the end surface of the reel (6), the reading head (4) is fixed on the rotary shaft (8), and the controller is connected to the motor (1), the circular grating (5), and the reading head (4).

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