A six-degree-of-freedom microgravity experimental device and method for asteroid exploration

Abstract

The present invention belongs to the field of microgravity detection technology and solves the problem in the prior art that when an asteroid probe jumps on a microgravity experimental platform, the gravity compensation generated by the constant torque motor is prone to large fluctuations. The present invention provides a six-degree-of-freedom microgravity experimental device and method for asteroid exploration. This device is provided with a tension compensation mechanism and a constant torque mechanism. The tension compensation mechanism can timely compensate for the tension value output by the constant torque motor when the asteroid exploration robot jumps, so that the suspension rope continuously applies a constant upward force to offset part of the asteroid probe's own weight. The constant torque mechanism can ensure that the gravity compensation of the asteroid probe in the Z-axis direction remains unchanged without the need for the constant torque motor to reverse, avoiding the problem of gravity compensation distortion caused by the change in the direction of the constant torque motor and significantly improving the stability and response speed of the system.

Description

Technical Field

[0001] The present invention relates to the field of microgravity detection technology, and in particular to a six-degree-of-freedom microgravity experimental device and method for asteroid detection. Background Art

[0002] The six-degree-of-freedom microgravity experiment device for asteroid exploration is used to conduct scientific research on the dynamics and kinematics of probes in the microgravity environment of asteroids. The relevant scientific research can provide technical reserves for future space missions and improve the success rate and safety of future asteroid exploration missions.

[0003] At present, the rope-type gravity compensation device often has shortcomings such as slow response and large fluctuations in compensation force during operation. When the asteroid probe jumps in the microgravity experimental device, the asteroid probe will rise from the lowest point to the highest point, and the speed will change from the maximum to 0. After that, the asteroid probe will move from the highest point to the lowest point, and the speed will begin to increase in the opposite direction. At the highest point, for the Z-axis drive assembly, the speed will change from forward rotation to reverse rotation. At this time, the Z-axis drive assembly will have a certain reaction time, and at the same time, a large fluctuation in the gravity compensation force will be generated. In addition, for the rope-type gravity compensation device, when replacing asteroid probes of different masses or simulating microgravity conditions under different conditions, there are often problems such as low versatility of the microgravity experimental device and complicated operation. Moreover, the constant torque mechanism in the existing asteroid detection six-degree-of-freedom microgravity experimental device fails to take into account the influence of friction, thereby reducing the accuracy of the output force and failing to achieve single-direction rotation of the constant torque motor. Summary of the Invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a six-degree-of-freedom microgravity experimental device and method for asteroid exploration.

[0005] According to a first aspect, a six-degree-of-freedom microgravity experimental device for asteroid exploration comprises:

[0006] Support frame;

[0007] A servo platform is provided on top of the support frame and can slide along the X-axis of the support frame. The servo platform is used to track the horizontal movement of the asteroid probe;

[0008] Constant tension system, the constant tension system is arranged on the follow-up platform and can slide along the Y-axis of the follow-up platform. The constant tension system includes a constant torque mechanism and a tension compensation mechanism. The constant torque mechanism includes a constant torque motor, a constant torque assembly and a reel connected in sequence. The constant torque assembly includes an inner disk and a ring arranged coaxially. The constant torque motor is rigidly connected to the inner disk. An elastic rod is provided in the inner disk. The elastic rod contacts the inner wall of the ring and moves along the contour of the ring. The contour of the ring changes periodically through 360°. The elastic rod is used to transfer the constant torque output by the constant torque motor to the ring. The ring transfers the constant torque to the reel. A lifting rope is provided in the reel. The lifting rope is used to tow the asteroid probe, and the lifting rope is connected to the tension compensation mechanism through several pulleys. The tension compensation mechanism is used to compensate for the gravity of the asteroid probe. The direction of gravity compensation is parallel to the Z-axis of the support frame.

[0009] Optionally, the profile of the collar satisfies the following formula:

[0010]

[0011] Where, is a fixed value, is the length from the center of the inner disk to the force point on the ring, It is the projection of the resultant force on the collar when the elastic rod moves on the tangent line of the collar contour.

[0012] Optionally, the elastic rod includes a rod body and a spring, a groove is provided on the outer circumference of the inner disk toward the collar, the end of the spring away from the collar is fixedly connected to the bottom of the groove, the spring is sleeved on the outer circumference of the rod body, and the end of the spring close to the collar is fixedly connected to the outer circumference of the rod body, the end of the rod body close to the collar has a pointed end, the pointed end abuts against the inner wall of the collar, and the elastic rod contracts or extends along the contour of the collar.

[0013] Optionally, the path of the torque transmitted to the ring when the elastic rod performs a contraction movement is a first contour, and the first contour is an outward convex arc. The path of the torque transmitted to the ring when the elastic rod performs an extension movement is a second contour, and the second contour is an outward convex arc. The contour of the ring is closed by alternatingly connecting the first contour and the second contour.

[0014] Optionally, the profile of the collar is determined by the following formula:

[0015]

[0016] Get All Corresponding and , get the outline of the ring;

[0017] Where, Is an elastic rod with The angle in the positive direction of the axis, , is the spring constant, is the intermediate variable defined, It is the distance from the center of the inner disk to the force point on the contour of the ring when the elastic rod contracts. It is the distance from the center of the inner disk to the force point on the contour of the ring when the elastic rod is extended. , yes and The minimum value of yes and The maximum value of and The maximum value of and When obtained, is the number of identical profiles of the ring within 360°, It is the torque transmitted to the ring by the elastic rod during its contraction movement. is the relative sliding friction coefficient between the elastic rod and the collar, It is the torque transmitted to the ring by the elastic rod's extension movement.

[0018] Optionally, the tension compensation mechanism includes a fixed rod, a rocker assembly, an elastic member and a driving assembly;

[0019] The rocker assembly includes a first rocker arm and a second rocker arm, the first rocker arm and the second rocker arm are rigidly connected, and the extension directions of the first rocker arm and the second rocker arm are parallel. The fixed rod is hingedly connected to the rocker arm assembly, and the hinge point is located at the connection position of the first rocker arm and the second rocker arm. The fixed rod is provided with a first pulley, a second pulley, and a third pulley along the Z-axis. The first pulley and the second pulley are provided on a side of the fixed rod facing the reel, and the third pulley is provided on the other side of the fixed rod.

[0020] The driving assembly includes a sliding member, a guide rail and a driving member, wherein the driving member is used to drive the sliding member to move along the guide rail;

[0021] One end of the elastic member is connected to the sliding member, and the other end of the elastic member is connected to an end of the second swing rod away from the first swing rod through a rope, and the rope is passed around the third pulley;

[0022] A fourth pulley is provided at one end of the first swing rod away from the fixed rod, and the suspension rope passes through the drum and sequentially passes through the second pulley, the first pulley and the fourth pulley to be connected to the asteroid probe.

[0023] Optionally, when the first swing arm, the second swing arm and the follower platform are arranged in parallel, the distance from the end of the second swing arm away from the first swing arm to the third pulley is equal to the stretching length of the elastic member.

[0024] Optionally, it also includes a camera and a control terminal. The camera is arranged at the bottom of the servo platform, and the control terminal is connected to the camera. The camera is used to capture the image of the asteroid probe. The control terminal receives the image captured by the camera. An X-axis motor is arranged on the servo platform, and a Y-axis motor is arranged on the support frame. The control terminal inputs speed parameters and position parameters to the X-axis motor and the Y-axis motor so that the servo platform can track the asteroid probe in real time.

[0025] Optionally, it also includes a base plate and a screw mechanism, one end of the base plate is hingedly connected to the bottom of the support frame, and the other end of the base plate is connected to the slider of the screw mechanism through a wire rope, and the motor of the screw mechanism drives the slider to move.

[0026] According to a second aspect, the present invention further provides a six-degree-of-freedom microgravity experimental method for asteroid exploration, which is based on any of the above-mentioned six-degree-of-freedom microgravity experimental devices for asteroid exploration, and includes the following steps:

[0027] S1. Connecting the asteroid probe to the suspension rope in the tension compensation mechanism, which provides a microgravity environment for the asteroid probe;

[0028] S2, providing a constant torque to the asteroid probe through a constant torque mechanism;

[0029] S3. Capture the image of the asteroid probe through the camera and transmit the image to the control terminal. Set a center point at the center of the camera image. Use the color conversion algorithm to filter out the marker and replace the position of the asteroid probe. The control terminal transmits speed and position parameters to the X-axis motor and Y-axis motor based on the distance between the marker and the center point to control the speed of the X-axis motor and Y-axis motor to ensure that the tracking platform tracks the asteroid probe in real time.

[0030] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0031] Embodiments of the present invention provide a six-degree-of-freedom microgravity experimental method and apparatus for asteroid exploration. This experimental apparatus includes a tension compensation mechanism that automatically adjusts the tension of the suspension rope through closed-loop control, ensuring that the gravity compensation force on the suspension rope connecting the asteroid probe remains constant. When replacing asteroid probes of different masses, the required force can be output to compensate for the asteroid probe's gravity by adjusting the lengths of the first and second pendulum arms. Furthermore, the apparatus can also accommodate elastic components with different elastic coefficients, avoiding the need for customized development of elastic components, reducing costs, and facilitating the selection, replacement, and maintenance of elastic components.

[0032] A constant torque mechanism is set in this experimental device. The constant torque motor outputs a constant torque, and the torque is transmitted to the reel through the constant torque component. The constant torque component includes a coaxially arranged inner disk and a collar. The elastic rod in the inner disk moves along the contour of the collar, and the contour of the collar changes periodically through 360°. The total torque transmitted from the inner disk to the collar is a constant value, so that when the asteroid probe jumps in the support frame, the constant torque motor rotates forward when the asteroid probe moves from the lowest point to the highest point. When the asteroid probe moves from the highest point to the lowest point, the collar is reversed without the need for the constant torque motor to reverse. This not only avoids the reaction time of the constant torque motor from forward to reverse, but also avoids the gravity compensation distortion problem caused by the change in the direction of the constant torque motor, and significantly improves the stability and response speed of the system.

[0033] In this experimental device, the constant torque motor outputs a constant torque to the drum, and the rope in the drum pulls the asteroid probe to move, making the overall structure of the follower platform simpler, reducing the overall mass and inertia of the follower platform, improving the response speed, and reducing the vibration and hysteresis of the follower platform.

[0034] This experimental method uses a color conversion visual recognition algorithm and a motor PID control algorithm to build an efficient and stable asteroid probe tracking system, ensuring the smooth operation of this experimental device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a schematic structural diagram of a six-degree-of-freedom microgravity experimental device for asteroid exploration provided by the present invention;

[0037] Figure 2 This is a schematic structural diagram of another perspective of a six-degree-of-freedom microgravity experimental device for asteroid exploration provided by the present invention;

[0038] Figure 3 is a structural schematic diagram of a constant tension system provided according to the present invention;

[0039] Figure 4 is a structural schematic diagram of the constant tension system provided by the present invention from another perspective;

[0040] Figure 5 is a structural schematic diagram of a constant torque assembly provided according to the present invention;

[0041] Figure 6 This is a schematic diagram of force analysis of a tension compensation mechanism provided by the present invention at a general position;

[0042] Figure 7 This is a schematic diagram of force analysis of a tension compensation mechanism provided by the present invention at a special position;

[0043] Figure 8 This is a physical model diagram of the outer contour of the collar provided according to the present invention;

[0044] Figure 9 2. It is a schematic diagram for analyzing the positive pressure exerted on the collar when the elastic rod according to the present invention performs a contraction movement;

[0045] Figure 10 is a schematic diagram of analyzing the positive pressure exerted on the collar when the elastic rod according to the present invention performs an elongation movement;

[0046] Figure 11 This is a schematic diagram of analyzing the friction force exerted on the collar when the elastic rod according to the present invention performs a contraction movement;

[0047] Figure 12 2. It is a schematic diagram of analyzing the friction force exerted on the collar when the elastic rod according to the present invention is extended;

[0048] Figure 13 2. It is a schematic diagram of velocity analysis of force points on the elastic rod and the collar when the elastic rod according to the present invention performs contraction motion;

[0049] Figure 14 2. It is a schematic diagram of velocity analysis of force points on the elastic rod and the collar when the elastic rod according to the present invention performs elongation motion;

[0050] Figure 15 According to the present invention, the speed parameter and position parameter are input and the a schematic diagram of a first profile of the generated collar;

[0051] Figure 16 According to the present invention, the speed parameter and position parameter are input and the Schematic diagram of the second profile of the generated collar.

[0052] Among them, 1. Support frame; 2. Follow-up platform; 3. Asteroid probe; 4. Constant torque mechanism; 41. Constant torque motor; 42. Constant torque assembly; 421. Inner disk; 4211. Groove; 422. Ring; 423. Elastic rod; 43. Drum; 431. Lifting rope; 5. Tension compensation mechanism; 51. Fixed rod; 511. First pulley; 512. Second pulley; 513. Third pulley; 52. First rocker arm; 521. Fourth pulley; 53. Second rocker arm; 54. Elastic member; 55. Sliding member; 56. Guide rail; 57. Rope; 6. Camera; 7. X-axis motor; 8. Y-axis motor; 9. Bottom plate; 10. Screw mechanism; 101. Motor; 102. Slide rail; 103. Slider; 11. Wire rope. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present invention are clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other implementations derived by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0054] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention. It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0055] When the existing asteroid probe jumps on the microgravity experimental platform, the asteroid probe will rise from the lowest point to the highest point, and the speed will change from the maximum to 0. Then the asteroid probe will move from the highest point to the lowest point, and the speed will start to increase in the opposite direction. At the highest point, for the gravity compensation motor in the Z-axis direction, the angular velocity will change from forward rotation to reverse rotation. At this time, the gravity compensation motor in the Z-axis direction will have a certain reaction time, which will produce a large fluctuation in the gravity compensation force. In this embodiment, the gravity compensation motor in the Z-axis direction is a constant torque motor 41.

[0056] To solve the above problems, an embodiment of the present invention provides a six-degree-of-freedom microgravity experimental device and method for asteroid exploration.

[0057] Reference Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a six-degree-of-freedom microgravity experimental device for asteroid exploration, including a support frame 1, a follower platform 2 and a constant tension system.

[0058] Reference Figure 1 As shown, the support frame 1 is assembled with aluminum alloy components, which not only ensures the lightness of the entire experimental device, but also ensures the stability of the support frame 1, and can stably carry other components. The follower platform 2 is arranged on the top of the support frame 1, and a chain is provided on the support frame 1 along its X-axis, so that the follower platform 2 slides along the X-axis of the support frame 1.

[0059] The constant tension system is set on the follower platform 2. A chain is set along the Y axis of the follower platform 2, so that the constant tension system slides along the Y axis of the follower platform 2, thereby realizing the constant tension system movement along the X axis and Y axis of the support frame 1, so that the follower platform 2 can track the horizontal movement of the asteroid probe 3. Figure 3 and Figure 5 As shown, the constant tension system includes a constant torque mechanism 4 and a tension compensation mechanism 5. The constant torque mechanism 4 includes a constant torque motor 41, a constant torque assembly 42 and a reel 43 connected in sequence. The constant torque assembly 42 includes an inner disk 421 and a collar 422 arranged coaxially. The constant torque motor 41 is rigidly connected to the central axis of the inner disk 421 through a coupling to achieve power transmission. An elastic rod 423 is provided in the inner disk 421. The elastic rod 423 contacts the inner wall of the collar 422 and moves along the contour of the collar 422. The elastic rod 423 is used to ensure that the inner disk 421 can transmit a constant torque to the ring 422, and then the ring 422 transmits the torque to the drum 43, thereby realizing the output of a constant torque to the drum 43. A suspension rope 431 is provided in the drum 43, and the suspension rope 431 is used to tow the asteroid probe 3, and the suspension rope 431 is connected to the tension compensation mechanism 5 through several pulleys. The tension compensation mechanism 5 is used to compensate for the gravity of the asteroid probe 3, and the direction of gravity compensation is parallel to the Z axis of the support frame 1, thereby accurately simulating the motion state of the asteroid probe 3 in a low gravity environment.

[0060] In order to ensure the integrity of the output torque and the requirement of unidirectional operation of the constant torque motor 41, the profile of the collar 422 changes periodically through 360°, that is, In the 360° motion range, the total torque transmitted from the inner disk 421 to the collar 422 is also periodic. is a fixed value and must satisfy and The product of is a constant value, that is, the profile of the collar 422 satisfies the following formula:

[0061]

[0062] Where, is a fixed value, is the length from the center of the inner disk to the force point on the ring, It is the projection of the resultant force on the collar when the elastic rod moves on the tangent line of the collar contour.

[0063] Furthermore, the elastic rod 423 includes a rod body and a spring. A groove 4211 is provided on the outer periphery of the inner disk 421 toward the ring 422. The end of the spring away from the ring 422 is fixedly connected to the bottom of the groove 4211. The spring is sleeved on the outer periphery of the rod body, and the end of the spring close to the ring 422 is fixedly connected to the outer periphery of the rod body. The end of the rod body close to the ring 422 has a tip, which abuts against the inner wall of the ring 422. The elastic rod 423 contracts or extends along the contour of the ring 422.

[0064] Reference Figure 8 As shown, considering When increasing or decreasing, the direction of the friction force is different, but the direction of the elastic force generated by the spring compression remains unchanged. Therefore, the total force of the elastic rod 423 is the sum of the projections of the elastic force and the friction force in the tangential direction. The change will cause the profile of the collar 422 to show different characteristics at different stages. Therefore, it is necessary to design two different outer ring profiles, corresponding to the torque transmission when the elastic rod 423 contracts and extends. Specifically, the path of the torque transmitted to the collar 422 when the elastic rod 423 contracts is the first profile, and the first profile is an outward convex arc. The path of the torque transmitted to the collar 422 when the elastic rod 423 extends is the second profile, and the second profile is an outward convex arc. In order to ensure the stability of the torque output and avoid and A sudden change occurs, and the contour of the collar 422 is closed by alternating connection of the first contour and the second contour, wherein, It is the position of the center of the inner disk 421. It is the position of the force point on the outline of the collar 422 when the elastic rod 423 performs the contraction movement. The position of the force point on the outline of the ring 422 when the elastic rod 423 is extended.

[0065] Among them, reference Figure 9 and Figure 11 As shown, the torque transmitted by the elastic rod 423 to the ring 422 during the contraction movement is , refer to Figure 10 and Figure 12 As shown, the torque transmitted by the elastic rod 423 to the ring 422 during the extension movement is The total torque transmitted from the inner disk 421 to the collar 422 is , , the profile of the collar 422 is determined by the following formula:

[0066] (1)

[0067] (2)

[0068] (3)

[0069] (4)

[0070] Where, is perpendicular to the line The axis, is perpendicular to the line The axis, It is the positive pressure exerted on the ring when the elastic rod contracts. It is the friction force exerted on the ring by the elastic rod during its contraction movement. yes and exist The sum of the axial projections, It is the positive pressure exerted on the ring when the elastic rod is extended. It is the friction force exerted on the ring when the elastic rod is extended. yes and exist The sum of the axial projections, It is the distance from the center of the inner disk to the force point on the contour of the ring when the elastic rod contracts. It is the distance from the center of the inner disk to the force point on the contour of the ring when the elastic rod is extended. It is the angle between the normal of the tangent line of the force point of the collar and the positive direction of the X axis when the elastic rod is contracting. It is the angle between the normal of the tangent line of the force point of the collar and the negative direction of the X axis when the elastic rod is extending. is the angle between the elastic rod and the positive direction of the X axis, ;

[0071] Substituting formula (3) into formula (1) yields:

[0072] (5)

[0073] Substituting formula (4) into formula (2) yields:

[0074] (6)

[0075] Where, When the elastic rod contracts In vertical The component of force in the axial direction, When the elastic rod contracts In vertical The component of force in the axial direction, is the relative sliding friction coefficient between the elastic rod and the collar;

[0076] Reference Figure 13 and Figure 14 As shown, the velocity analysis of the elastic rod 423 during movement is:

[0077] (7)

[0078] (8)

[0079] Where, It is the relative speed of the force point on the elastic rod relative to the force point on the collar when the elastic rod contracts. It is the absolute speed of the force point on the ring when the elastic rod contracts. It is the relative speed of the force point on the elastic rod relative to the force point on the collar when the elastic rod is extending. is the absolute velocity of the force point on the ring when the elastic rod is extending. It is the deformation of the spring when the elastic rod contracts. It is the deformation of the spring when the elastic rod is extended. yes The first derivative of yes The first derivative of yes The first derivative of ;

[0080] From Hooke's law we get:

[0081] (9)

[0082] (10)

[0083] Where, is the spring constant;

[0084] After finishing, we can get:

[0085] (11)

[0086] (12)

[0087] By moving the items, we can get:

[0088] (13)

[0089] (14)

[0090] in:

[0091] (15)

[0092] (16)

[0093] (17)

[0094] (18)

[0095] (19)

[0096] Where, For the defined intermediate variables, variables It does not have a clear physical meaning and is only used as an auxiliary symbol in the derivation process. is the original length of the spring, is the distance from the top of the spring to the force point of the collar, is the distance from the bottom of the groove to the center of the inner disk. , yes and The minimum value of yes and The maximum value of and The maximum value of and When obtained, among which, is the number of identical profiles of the collar within 360°;

[0097] Substituting formulas (15), (16), (17), (18) and (19) into formulas (13) and (14), we obtain:

[0098] (20)

[0099] (twenty one)

[0100] Integrating both ends of formula (20) and formula (21) yields:

[0101] (twenty two)

[0102] (twenty three)

[0103] Where, and are all integral constants;

[0104] when hour:

[0105] (twenty four)

[0106] (25)

[0107] when hour:

[0108] (26)

[0109] (27)

[0110] Substituting formula (24) and formula (25) into formula (22) and formula (23) respectively, we obtain:

[0111] (28)

[0112] (29)

[0113] Combining formulas (22), (23), (28) and (29), we can obtain the general form of the collar profile expression:

[0114] (30)

[0115] (31).

[0116] Get All Corresponding and , and obtain the outline of the ring 422.

[0117] By further determining the actual moment required to achieve constant torque output, the elastic coefficient of the spring, and the dynamic friction coefficient between the elastic rod and the collar, and through mathematical processing and calculation, the ideal collar profile that meets the constant torque output conditions can be obtained.

[0118] Among them, in the constant torque mechanism, take 、 、 、 、 、 ,Require Take an odd number, take = = 0.6 , total torque =1.2 , calculated =0.058397 , =0.67108 , processed by computer program, and thus obtained Figure 15 and Figure 16 The rectangular coordinate system of the ring 422 is generated.

[0119] Reference Figure 3 and Figure 4 As shown, the tension compensation mechanism 5 includes a fixed rod 51, a rocker assembly, an elastic member 54 and a driving assembly. The rocker assembly includes a first rocker 52 and a second rocker 53. The first rocker 52 and the second rocker 53 are rigidly connected, and the extension directions of the first rocker 52 and the second rocker 53 are parallel. The fixed rod 51 is hingedly connected to the rocker assembly, and the hinge point is located at the connection position of the first rocker 52 and the second rocker 53. A first pulley 511, a second pulley 512 and a third pulley 513 are provided on the fixed rod 51 along the Z-axis. The first pulley 511 and the second pulley 512 are provided on the side of the fixed rod 51 facing the reel 43, and the third pulley 513 is provided on the other side of the fixed rod 51. A fourth pulley 521 is provided at the end of the first rocker 52 away from the fixed rod 51. The suspension rope 431 The warp drum 43 passes through the second pulley 512, the first pulley 511 and the fourth pulley 521 in sequence and is connected to the asteroid probe 3. The driving assembly includes a sliding member 55, a guide rail 56 and a driving member. The driving member is used to drive the sliding member 55 to move along the guide rail 56. One end of the elastic member 54 is connected to the sliding member 55, and the other end of the elastic member 54 is connected to the end of the second rocker 53 away from the first rocker 52 through a rope 57, and the rope 57 passes around the third pulley 513. The tension compensation mechanism 5 can quickly compensate for the output tension value of the reaction gap of the constant torque motor 41 when the asteroid probe 3 jumps, so that the suspension rope 431 continuously outputs a constant upward force to continuously offset part of the gravity of the asteroid probe 3 itself, thereby achieving a simulation of the jumping of the asteroid probe 3 in a low gravity environment.

[0120] Specifically, refer to Figure 7 As shown, when the elastic member 54 is in a special stretched state, that is, when the first swing rod 52, the second swing rod 53 and the follower platform 2 are arranged in parallel, the distance from the end of the second swing rod 53 away from the first swing rod 52 to the third pulley 513 is equal to the stretched length of the elastic member 54, that is, Just the elongation of the elastic member 54, refer to Figure 6 and Figure 7 As shown, is the position of the first pulley 511, is the position of the fourth pulley 521 when the tension compensation mechanism is in the normal position, is the position of the fourth pulley 521 when the tension compensation mechanism is in a special position, is the position of the third pulley 513, is the position where the end of the second swing rod 53 is away from the first swing rod 52 when the tension compensation mechanism is in the normal position, When the tension compensation mechanism is in a special position, the second swing rod 53 is located away from the end of the first swing rod 52. The tension provided by the elastic member 54 in different states is:

[0121] (32)

[0122] (33)

[0123] Where, is the stiffness coefficient of the elastic member, It is the tension provided by the elastic part when the tension compensation mechanism is in a special position. When the tension compensation mechanism is in a special position to The geometric length of It is the tension provided by the elastic member when the tension compensation mechanism is in the normal position. When the tension compensation mechanism is in the normal position to The geometric length of

[0124] According to Newton's third law:

[0125] (34)

[0126] Where, The tension compensation mechanism is in the normal position. The vertical component of the resultant force is It is the force acting on the vertical rope when the tension compensation is in the normal position, that is, the tension of the vertical rope after compensation;

[0127] When the tension compensation mechanism is in the general position, take the torque about point A and get:

[0128] (35)

[0129] Where, It is the torque generated by the fourth pulley on the first pulley when the tension compensation mechanism is in the normal position. It is the torque generated by the end of the second swing rod away from the first swing rod on the first pulley when the tension compensation mechanism is in the normal position. yes The moment of inertia of the rod, yes Angular acceleration of the rod when it rotates around a fixed axis;

[0130] Due to the actual situation and are both small, the right side of formula (35) is approximately 0, and we get:

[0131] (36)

[0132] Thus we get:

[0133] (37)

[0134] Where, For to The displacement vector, For to The displacement vector;

[0135] Further we get:

[0136] (38)

[0137] Where, is a line segment With rope or line segment and line segment The angle between is a line segment With line segment The angle between When the tension compensation mechanism is in the normal position to The geometric length of When the tension compensation mechanism is in the normal position to The geometric length of

[0138] exist In the equation, we can get from the law of sine:

[0139] (39)

[0140] Combining formula (33), formula (38) and formula (39) yields:

[0141] (40)

[0142] It is known that no matter and What value to take? That is, when the tension compensation mechanism is in any general position, the force of the fourth pulley 521 on the suspension rope 431 in the vertical direction is is a constant, When the tension compensation mechanism is in the normal position to The geometric length.

[0143] When replacing asteroid probes 3 of different masses, different pulling forces are required , or when elastic members 54 with different elastic coefficients are selected, the microgravity environment can be simulated by simply changing the lengths of the first pendulum rod 52 and the second pendulum rod 53.

[0144] The tension compensation mechanism 5 has the characteristics of rapid response and high reliability. When the asteroid probe 3 jumps, it can instantly compensate for the changes in the tension value output by the constant torque component 42, so that the suspension rope 431 continuously applies a constant upward force to offset part of the self-weight of the asteroid probe 3. The constant torque mechanism 4 ensures that the constant torque motor 41 can achieve constant gravity compensation for the asteroid probe 3 in the Z-axis direction without reversing.

[0145] Reference Figure 1 and Figure 2 As shown, this experimental device also includes a camera 6, a control terminal, a base plate 9 and a screw mechanism 10. The camera 6 is arranged at the bottom of the follower platform 2, and the camera 6 can rotate within a range of 360 degrees. The control terminal is connected to the camera 6. The camera 6 is used to capture the image of the asteroid probe 3. The control terminal receives the image captured by the camera 6. An X-axis motor 7 is provided on the follower platform 2, and a Y-axis motor 8 is provided on the support frame 1. The control terminal inputs speed parameters and position parameters to the X-axis motor 7 and the Y-axis motor 8, and the X-axis motor 7 drives the follower 2 to rotate. The moving platform 2 moves along the X-axis of the support frame 1, and the Y-axis motor 8 drives the constant tension system to move along the Y-axis of the following platform 2, so that the following platform 2 can track the asteroid probe 3 in real time. One end of the base plate 9 is hingedly connected to the bottom of the support frame 1, and the other end of the base plate 9 is connected to the slider of the screw mechanism 10 through a wire rope 11. The motor of the screw mechanism 10 drives the slider to move, and the screw mechanism 10 can adjust the angle between the base plate 9 and the bottom of the support frame 1, so that the asteroid probe 3 can climb and descend under different slope conditions.

[0146] An embodiment of the present invention provides a six-degree-of-freedom microgravity experiment method for asteroid exploration, which is based on an asteroid exploration six-degree-of-freedom microgravity experiment device according to the above embodiment and includes the following steps:

[0147] S1. Connect the asteroid probe 3 to the suspension rope 431 in the tension compensation mechanism 5. The tension compensation mechanism 5 provides a microgravity environment for the asteroid probe 3.

[0148] S2, providing a constant torque to the asteroid probe 3 through the constant torque mechanism 4;

[0149] S3. Capture the image of the asteroid probe 3 through the camera 6 and transmit the image to the control terminal. The control terminal performs closed-loop control on the speed of the X-axis motor 7 and the Y-axis motor 8 through the visual recognition algorithm and the PID algorithm. Specifically, the control terminal realizes the initialization resolution of the camera 6, sets a center point at the center of the image of the camera 6, and selects the marker through the color conversion algorithm to replace the position of the asteroid probe 3. The control terminal transmits the speed and position parameters to the X-axis motor 7 and the Y-axis motor 8 based on the distance between the marker and the center point to control the rotation speed of the X-axis motor 7 and the Y-axis motor 8, that is, When the distance between the marker and the center point becomes larger, the control terminal transmits speed and position parameters to the X-axis motor 7 and the Y-axis motor 8, so that the rotation speed of the X-axis motor 7 and the Y-axis motor 8 increases, and the movement speed of the follower platform 2 becomes faster. When the distance between the marker and the center point becomes smaller, the control terminal transmits speed and position parameters to the X-axis motor 7 and the Y-axis motor 8, so that the rotation speed of the X-axis motor 7 and the Y-axis motor 8 decreases, and the movement speed of the follower platform 2 slows down. When the marker coincides with the center point, the control terminal no longer transmits speed and position parameters to the X-axis motor 7 and the Y-axis motor 8, to ensure that the follower platform 2 tracks the asteroid probe 3 in real time.

[0150] Among them, both the X-axis motor 7 and the Y-axis motor 8 use servo motors to ensure smooth speed changes. A combined interface solution of a single network port and USB is used to connect the drivers of the X-axis motor 7 and the Y-axis motor 8 and the host computer, thereby improving the wide applicability and compatibility of the equipment. At the same time, the USB interface provides a sending indicator light TX and a receiving indicator light RX for monitoring the communication status of the interface. A PID control algorithm is used to realize speed control of the X-axis motor 7 and the Y-axis motor 8, providing precise speed regulation and good dynamic response, ensuring that the X-axis motor 7 and the Y-axis motor 8 operate within the expected speed range and maintain high accuracy and stability.

[0151] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A six-degree-of-freedom microgravity experimental device for asteroid exploration, characterized by: include: Support frame (1); A follower platform (2), the follower platform (2) is arranged on the top of the support frame (1) and can slide along the X-axis of the support frame (1), and the follower platform (2) is used to track the horizontal movement of the asteroid probe (3); A constant tension system is provided on a follower platform (2) and can slide along the Y axis of the follower platform (2). The constant tension system includes a constant torque mechanism (4) and a tension compensation mechanism (5). The constant torque mechanism (4) includes a constant torque motor (41), a constant torque assembly (42) and a reel (43) connected in sequence. The constant torque assembly (42) includes a coaxially arranged inner disk (421) and a sleeve (422). The constant torque motor (41) is rigidly connected to the inner disk (421). An elastic rod (423) is provided in the inner disk (421). The elastic rod (423) contacts the inner wall of the sleeve (422) and moves along the sleeve (422). 22), the contour of the collar (422) changes periodically through 360°, the elastic rod (423) is used to transmit the constant torque output by the constant torque motor (41) to the collar (422), the collar (422) transmits the constant torque to the reel (43), a suspension rope (431) is provided in the reel (43), the suspension rope (431) is used to tow the asteroid probe (3), and the suspension rope (431) is connected to the tension compensation mechanism (5) through a plurality of pulleys, the tension compensation mechanism (5) is used to perform gravity compensation on the asteroid probe (3), and the direction of gravity compensation is parallel to the Z axis of the support frame (1).

2. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 1, characterized in that: The profile of the collar (422) satisfies the following formula: Where, is a fixed value, is the length from the center of the inner disk to the force point on the ring, It is the projection of the resultant force on the collar when the elastic rod moves on the tangent line of the collar contour.

3. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 2, characterized in that: The elastic rod (423) includes a rod body and a spring. A groove (4211) is provided on the outer periphery of the inner disk (421) facing the collar (422). The end of the spring away from the collar (422) is fixedly connected to the bottom of the groove (4211). The spring is sleeved on the outer periphery of the rod body, and the end of the spring close to the collar (422) is fixedly connected to the outer periphery of the rod body. The end of the rod body close to the collar (422) has a tip, which abuts against the inner wall of the collar (422). The elastic rod (423) contracts or extends along the contour of the collar (422).

4. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 3, characterized in that: The path of the torque transmitted to the collar (422) when the elastic rod (423) performs a contraction movement is a first contour, the first contour is an outward convex arc, and the path of the torque transmitted to the collar (422) when the elastic rod (423) performs an extension movement is a second contour, the second contour is an outward convex arc, and the contour of the collar (422) is closed by alternately connecting the first contour and the second contour.

5. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 4, characterized in that: The profile of the collar (422) is determined by the following formula: Get All Corresponding and , obtaining the outline of the collar (422); Where, Is an elastic rod with The angle in the positive direction of the axis, , is the spring constant, is the intermediate variable defined, It is the distance from the center of the inner disk to the force point on the contour of the ring when the elastic rod contracts. It is the distance from the center of the inner disk to the force point on the contour of the ring when the elastic rod is extended. , yes and The minimum value of yes and The maximum value of and The maximum value of and When obtained, is the number of identical profiles of the ring within 360°, It is the torque transmitted to the ring by the elastic rod during its contraction movement. is the relative sliding friction coefficient between the elastic rod and the collar, It is the torque transmitted to the ring by the elastic rod during its extension movement.

6. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 1, characterized in that: The tension compensation mechanism (5) includes a fixed rod (51), a rocker assembly, an elastic member (54), and a drive assembly; The rocker assembly comprises a first rocker (52) and a second rocker (53), wherein the first rocker (52) and the second rocker (53) are rigidly connected, and the extension directions of the first rocker (52) and the second rocker (53) are parallel. The fixed rod (51) is hingedly connected to the rocker assembly, and the hinge point is located at the connection position of the first rocker (52) and the second rocker (53). A first pulley (511), a second pulley (512), and a third pulley (513) are provided on the fixed rod (51) in the direction of the Z axis. The first pulley (511) and the second pulley (512) are provided on one side of the fixed rod (51) facing the reel (43), and the third pulley (513) is provided on the other side of the fixed rod (51). The driving assembly comprises a sliding member (55), a guide rail (56) and a driving member, wherein the driving member is used to drive the sliding member (55) to move along the guide rail (56); One end of the elastic member (54) is connected to the sliding member (55), and the other end of the elastic member (54) is connected to an end of the second swing rod (53) away from the first swing rod (52) through a rope (57), and the rope (57) is passed around the third pulley (513); A fourth pulley (521) is provided at one end of the first swing rod (52) away from the fixed rod (51), and the suspension rope (431) passes through the drum (43) and sequentially passes through the second pulley (512), the first pulley (511) and the fourth pulley (521) to be connected to the asteroid probe (3).

7. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 6, characterized in that: When the first swing rod (52), the second swing rod (53) and the follower platform (2) are arranged in parallel, the distance from the end of the second swing rod (53) away from the first swing rod (52) to the third pulley (513) is equal to the stretching length of the elastic member (54).

8. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 1, characterized in that: The invention also includes a camera (6) and a control terminal. The camera (6) is arranged at the bottom of the servo platform (2). The control terminal is connected to the camera (6). The camera (6) is used to capture the image of the asteroid probe (3). The control terminal receives the image captured by the camera (6). An X-axis motor (7) is arranged on the servo platform (2). A Y-axis motor (8) is arranged on the support frame (1). The control terminal inputs speed parameters and position parameters to the X-axis motor (7) and the Y-axis motor (8) so that the servo platform (2) can track the asteroid probe (3) in real time.

9. The six-degree-of-freedom microgravity experimental device for asteroid exploration according to claim 1, characterized in that: It also includes a base plate (9) and a screw mechanism (10), one end of the base plate (9) is hingedly connected to the bottom of the support frame (1), and the other end of the base plate (9) is connected to a slider of the screw mechanism (10) through a steel wire rope (11), and the motor of the screw mechanism (10) drives the slider to move.

10. A six-degree-of-freedom microgravity experimental method for asteroid exploration, based on the six-degree-of-freedom microgravity experimental device for asteroid exploration according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, connecting the asteroid probe (3) to the suspension rope (431) in the tension compensation mechanism (5), and the tension compensation mechanism (5) provides a microgravity environment for the asteroid probe (3); S2, providing a constant torque to the asteroid probe (3) through a constant torque mechanism (4); S3. Capture the image of the asteroid probe (3) through the camera (6) and transmit the image to the control terminal. The control terminal sets a center point at the center of the image of the camera (6). The marker is selected through the color conversion algorithm and replaces the position of the asteroid probe (3). The control terminal transmits speed and position parameters to the X-axis motor (7) and the Y-axis motor (8) based on the distance between the marker and the center point to control the rotation speed of the X-axis motor (7) and the Y-axis motor (8) to ensure that the follower platform (2) tracks the asteroid probe (3) in real time.

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