Active and passive integrated magnetic suspension five-overload load platform based on parallel mechanism

Abstract

The invention relates to the technical field of aerospace, in particular to an active and passive integrated magnetic suspension five-overload platform based on a parallel mechanism. Comprising a parallel mechanism frame and a magnetic suspension super platform which are connected with each other, the parallel mechanism frame is further connected with a satellite body, and the magnetic suspension super platform is further connected with a load; the parallel mechanism frame comprises a plurality of branched chains and is used for providing attitude maneuvering capability for the magnetic suspension super-platform, the magnetic suspension super-platform comprises a magnetic suspension vibration isolator, a voice coil motor, a magnetic suspension movable platform and a magnetic damper, the magnetic suspension movable platform is used for mounting a load, and the voice coil motor is connected with the magnetic suspension movable platform and the parallel mechanism frame; the capability of actively adjusting the magnetic suspension moving platform is provided, and the magnetic suspension vibration isolator is used for reducing vibration in the moving process. When the posture is not actively adjusted and the vibration is actively suppressed, magnetic suspension of the load and the platform can be maintained with less control, and the transmission of the vibration can be physically blocked, so that more energy consumption is saved.

Description

Technical Field

[0001] The invention relates to the field of aerospace technology, and in particular to an active and passive integrated magnetic suspension five-superload platform based on a parallel mechanism. Background Art

[0002] With the rapid development of aerospace technology, high-precision spacecraft such as high-resolution remote sensing satellites, laser communication satellites and space telescopes have put forward increasingly higher requirements on the attitude accuracy, stability and quietness of the payload. At the same time, agility has often become an important indicator of low-orbit satellites. Traditional three-axis stabilized satellites mainly use flywheels or control moment gyroscopes (CMG) to maneuver and stabilize the platform's attitude, and use the platform to drive payloads such as cameras to maneuver and stabilize the attitude to achieve the pointing requirements of the payload.

[0003] In response to the requirements of ultra-precision, ultra-stability, ultra-quietness, ultra-agility and ultra-wide pointing of payload attitude, passive vibration isolation, active and passive vibration isolation (such as "three supers": ultra-precision, ultra-stability and ultra-agility) and active vibration control (such as "double supers": ultra-precision and ultra-stability) driven by control moment gyroscopes have been developed. Among them, passive vibration isolation has a good effect on high-frequency vibration isolation, but is powerless against low-frequency micro-vibrations, and has a certain amplification effect on medium-frequency micro-vibrations. The "three supers" platform is an active and passive integrated vibration isolation platform for attitude control through CMG, which realizes the attitude agility and ultra-wide attitude maneuvering of the satellite platform through CMG; obviously, its control ability of micro-vibration is further than that of passive vibration isolation. It uses voice coil motors and membrane springs to form active and passive integrated vibration isolators, which can actively control medium and low frequency vibrations. Given that it has a certain support stiffness, the micro-vibration of the platform is still partially transmitted to the payload; its ultra-agility performance is to drive the platform to quickly maneuver through CMG and other driving platforms, and then through the transmission of the "three supers" platform, drive the payload to achieve the so-called attitude agility maneuvering. In order to isolate micro-vibrations more thoroughly, the "Double Super" uses active magnetic levitation. When attitude control is required, control force and torque are generated through the magnetic levitation mechanism. When the attitude is stable within a certain range, the magnetic levitation mechanism is powered off and the payload is in a floating state. Therefore, it is basically not affected by the micro-vibration of the platform. Obviously, its micro-vibration control is more thorough, but the payload disturbance is not considered; and its attitude maneuver is still indirectly achieved by driving the platform's attitude maneuver through the platform's attitude control system. It can be seen that whether it is passive vibration isolation, the "Three Super" platform or the "Double Super" platform, they all indirectly drive the payload to control attitude through the attitude maneuver and stability of the satellite platform. The contradiction between the large inertia of the entire satellite and the limited control torque makes it difficult to achieve higher agility and other super performance. Summary of the invention

[0004] The embodiment of the present invention provides an active and passive integrated magnetic levitation five-superload platform based on a parallel mechanism. When the posture is not actively adjusted and the vibration is not actively suppressed, less control can maintain the magnetic levitation of the load and the platform, which can physically block the transmission of vibration, thereby saving more energy.

[0005] The embodiment of the present invention provides an active-passive integrated magnetic suspension five-superload platform based on a parallel mechanism, comprising a parallel mechanism frame and a magnetic suspension super platform connected to each other, wherein the parallel mechanism frame is also connected to a satellite body, and the magnetic suspension super platform is also connected to a load;

[0006] The parallel mechanism framework includes a plurality of branches for providing the magnetic levitation super platform with posture maneuverability. The magnetic levitation super platform includes a magnetic levitation vibration isolator, a voice coil motor, a magnetic levitation moving platform and magnetic damping. The magnetic levitation moving platform is used to install the load. The voice coil motor is respectively connected to the magnetic levitation moving platform and the parallel mechanism framework to provide the ability to actively adjust the magnetic levitation moving platform. The magnetic levitation vibration isolator is used to reduce vibration during movement.

[0007] In a possible design, the parallel mechanism frame includes a parallel mechanism base, a grating code disk, a rotary motor, a lead screw, a nut, a damping rod, a hinge, a parallel mechanism moving platform and an electric cylinder;

[0008] The parallel mechanism frame adopts a 3-PURU / 1-PRU or 3-PURU / 1-RU multi-branch parallel configuration, so that the parallel mechanism frame can realize three-axis rotational freedom and large-angle rotation. The parallel mechanism base is a triangle, and its three vertices are each provided with two groups of rotating motors and the grating code disk, and its three sides are provided with lead screws. Each group of the rotating motor and the grating code disk is connected to one end of the lead screw to control the lead screw to rotate according to a preset number of turns. One end of the damping rod is threadedly connected to the lead screw through a nut, and the other end is connected to the parallel mechanism moving platform through a hinge. The parallel mechanism moving platform is connected to the magnetic suspension moving platform through the voice coil motor and the magnetic suspension vibration isolator, and the electric cylinder is arranged in the middle of the parallel mechanism base;

[0009] The lead screw is driven to rotate by a rotating motor, which pushes the nut to translate, and then the dynamic platform of the dynamic parallel mechanism is rotated through the hinge, ultimately achieving the direction of the magnetic levitation super platform at any continuous angle in the local area, realizing three-axis large-range attitude maneuvering of the load.

[0010] In a possible design, the damping rod is composed of a spring damper, which is used to passively isolate medium and high frequency vibrations on the satellite, that is, to first isolate the vibrations transmitted from the satellite platform to the magnetic levitation super platform to a certain extent.

[0011] In a possible design, the parallel mechanism framework includes structural damping, which is used to dissipate energy of local resonance and improve the ultra-stable and ultra-quiet performance of the load.

[0012] In a possible design, the magnetic levitation vibration isolator supports the magnetic levitation moving platform and the parallel mechanism moving platform in a contactless manner through the repulsive force of the permanent magnet, so as to limit the relative positions of the two within a certain range, thereby forming a passive vibration isolation system.

[0013] In a possible design, the magnetic levitation vibration isolator includes a mounting rod, a mounting sleeve, a first axial permanent magnet, a second axial permanent magnet, a magnetic isolation ring, an inner radiating permanent magnet, an outer radiating permanent magnet, a sleeve, and a locking ring. The interior of the mounting sleeve is the sleeve, and the middle of the sleeve is provided with a first axial permanent magnet. Two of the second axial permanent magnets, two of the magnetic isolation rings, two of the inner radiating permanent magnets, two of the outer radiating permanent magnets, and two of the locking rings are respectively arranged on both sides of the first axial permanent magnet. The mounting rod is connected to the magnetic levitation moving platform, and the mounting sleeve is connected to the parallel mechanism moving platform.

[0014] In one possible design, the voice coil motor is used to provide force and torque with 6 degrees of freedom.

[0015] In a possible design, a displacement sensor is connected in parallel to the axial direction of each voice coil motor to detect the relative axial position change of the voice coil motor.

[0016] In a possible design, the stator part of the voice coil motor is fixed to the parallel mechanism moving platform, and the mover part of the voice coil motor is fixed to the magnetic suspension moving platform.

[0017] In one possible design, the voice coil motor includes a first voice coil motor and a second voice coil motor, the axes of the first voice coil motor and the second voice coil motor are perpendicular, wherein four of the first voice coil motors are used to control the axial deflection and axial movement of the magnetic levitation dynamic platform, and four of the second voice coil motors are used to control the translation in two horizontal directions and the rotation around the axis.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] This patent targets the existing attitude control system, which drives the attitude maneuvering and stabilization of the entire satellite with large mass and large inertia, and drives the small mass and small inertia payload to perform attitude maneuvering and stabilization, resulting in a huge waste of precious resources on the satellite, such as the weight and power consumption of the control system; and also causes the devices on the satellite that do not need to be maneuvered to maneuver, thereby forcing these devices to be coordinated and controlled, which also increases the complexity of control. It can be seen that this traditional attitude control mode not only causes a lot of waste, but also limits the acceleration and speed of the attitude maneuvering of the payload; and the fixed connection mode between the payload and the platform causes the disturbance on the platform to be directly transmitted to the payload, affecting the ultra-stability and ultra-quietness of the payload attitude. For this reason, a payload-oriented direct attitude control mode of the payload is proposed, as well as an active and passive integrated magnetic suspension "super" platform based on a parallel mechanism to realize the payload attitude control mode. That is, a spatial parallel mechanism is used to realize the rapid deflection of the moving platform at any continuous angle within the local spherical area, thereby driving the load on the moving platform to maneuver in any direction and rapid posture within the local spherical area, and realizing the ultra-agility of the load; and the active and passive integrated magnetic suspension super-platform inside the moving platform can realize true contactless support, and can also realize active vibration control, reduce vibration transmission, and realize ultra-stable and ultra-quiet loads; the attitude large-range maneuvering of the parallel mechanism and the attitude small-range adjustment of the active and passive integrated magnetic suspension super-platform inside the moving platform are the two-level attitude control mode, which takes into account the agility and accuracy of attitude control; and the platform can reduce the configuration requirements of the attitude control system on the spacecraft, and can reduce the weight and power consumption of the attitude control system. It can be seen that the present invention better takes into account the attitude control requirements of the ultra-precision, ultra-stable, ultra-quiet, and ultra-agile loads and the weight, power consumption, and other costs of the system. As a general platform, the present invention can adapt to the application requirements of today's high-resolution agile satellites and precision strike weapon platforms. It can be seen that this patent is goal-oriented, and the method of using a parallel mechanism and active and passive magnetic suspension integrated direct drive loads to control the attitude of the load has significant advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0021] Figure 1 It is a schematic diagram of the layout of the super-platform robot satellite of the present invention;

[0022] Figure 2 It is a schematic diagram of the super platform of the three-branch parallel mechanism of the present invention;

[0023] Figure 3 It is a schematic diagram of the framework of the three-branch parallel mechanism of the present invention;

[0024] Figure 4 A schematic diagram of the internal structure of the magnetic levitation super platform of the present invention;

[0025] Figure 5 It is a schematic diagram of the internal structure of the passive magnetic suspension unit of the present invention;

[0026] Figure 6 This is a block diagram of the super-platform robot satellite control system of the present invention.

[0027] In the figure:

[0028] 1-magnetic levitation five-superload platform; 2-load; 3-satellite body; 4-parallel mechanism frame; 5-magnetic levitation super platform; 6-parallel mechanism base; 7-grating code disk; 8-rotating motor; 9-screw; 10-nut; 11-damping rod; 12-hinge; 13-parallel mechanism moving platform; 14-electric cylinder; 15-magnetic levitation isolator; 16-first voice coil motor; 17-second voice coil motor; 18-magnetic levitation moving platform; 19-mounting rod; 20-mounting sleeve; 21-first axial permanent magnet; 22-second axial permanent magnet; 23-magnetic isolation ring; 24-inner radiation permanent magnet; 25-outer radiation permanent magnet; 26-sleeve; 27-locking ring. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present invention are described at the angles shown in the drawings and should not be understood as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0032] As mentioned above, the traditional model still has the following problems:

[0033] 1) The mass and moment of inertia of the entire satellite are much larger than the mass characteristic parameters of the payload. The limited angular momentum and control torque of the inertial actuators such as the onboard control torque gyro limit the acceleration and speed of the attitude maneuver of the entire satellite. Generally, the average attitude maneuvering speed of the entire satellite does not exceed 5° / s. It can be seen that the agility of the payload also depends on the agility of the satellite platform, which is still insufficient. It can be seen that the attitude control mode of driving a small payload through a large platform causes a large waste of angular momentum capacity and torque of the attitude control, and also causes a waste of resources such as weight and power consumption of the attitude control system.

[0034] Table 1 Ultra-agile maneuverability performance indicators of typical satellite platforms

[0035]

[0036] 2) The flexibility and low damping of the onboard solar panels and other structures often make it take several seconds for the satellite to stabilize its attitude, which to some extent weakens the agility and rapid stability of the attitude maneuvering of the entire satellite. It can be seen that the attitude maneuvering mode of driving a small payload through a large platform causes unnecessary onboard components, especially the coordinated movement of flexible components in a large range, which increases the stabilization time of the entire satellite. It also limits the agility and rapid stability of the satellite and limits the bandwidth of the onboard control system.

[0037] 3) The broadband micro-vibration generated by high-speed rotating mechanisms such as flywheels and CMGs during operation will affect the platform's attitude, performance indicators such as the direction of the payload, and the imaging quality of the camera. Today, the traditional method of suppressing on-board vibration mainly uses a dedicated vibration isolation device to isolate micro-vibration on the vibration transmission path. However, the efficiency of the widely used contact vibration isolation needs to be improved.

[0038] 4) In the streamlined configuration of the control moment gyro (CMG), the internal singularity problem limits the application of satellite rapid maneuvers to a certain extent; and the redundant configuration of the CMG increases the burden of the satellite such as weight and power consumption. Therefore, there is an irreconcilable contradiction between the resource consumption cost and the simplicity of application of the CMG-based attitude control system, which is not conducive to large-scale promotion.

[0039] In summary, the traditional mode of indirectly realizing payload attitude control by relying on the attitude control of the satellite platform is time-consuming, labor-intensive, uneconomical and unprofitable. Therefore, it is necessary to study new mechanisms for payload attitude control based on the application requirements of the payload to achieve the goals of rapid maneuverability and rapid stabilization of the payload attitude.

[0040] Compared with the existing technology, this patent has the following advantages:

[0041] (1) The traditional satellite attitude control strategy is based on the satellite platform, that is, the attitude control of the local area is driven by the whole, that is, it mainly relies on flywheels or control torque gyroscopes (CMG) and other actuators to drive the overall maneuver of the spacecraft, and then drive the payload whose mass and moment of inertia are much smaller than the mass and moment of inertia of the whole satellite or the whole device to perform attitude maneuvers and stability, which causes a waste of resources in the attitude control system. The attitude control strategy of this patent is directly guided by the attitude of the payload, that is, the parallel mechanism is used to directly drive the rapid attitude maneuver and stability of the payload by borrowing force and torque from the satellite platform. That is, the spatial parallel mechanism is used to realize the arbitrary continuous angle maneuver and arbitrary direction of the payload in a large local spherical area, and then the magnetic suspension super platform is driven by the moving platform to directly realize the ultra-agile maneuver of the payload. Given that the mass and moment of inertia of the payload are much smaller than those of the whole satellite or the whole device, the control torque required for the direct attitude control of the payload in this patent is much smaller, which can significantly reduce the configuration requirements of the attitude actuator system such as CMG.

[0042] (2) The traditional attitude control mode, which affects the whole body when one hair moves, is not conducive to multi-point orientation, such as the orientation of the battery array to the sun and the orientation of the communication to the earth. This maneuvering mode requires the coordinated maneuvering of many actuators on the satellite. However, this patent only directly drives the payload, and the platform of the satellite is almost motionless, so it basically does not break the orientation of the battery array and antenna, etc.; even if the balance of the original platform is broken, the angle of the platform attitude deflection caused by the payload maneuver is much smaller than the angle of the traditional direct maneuver. The greater the inertia difference between the payload and the spacecraft, the smaller the impact of the payload attitude maneuver on the spacecraft. Therefore, when applying the present invention, the angle of reverse maneuver required for the antenna and sailboard that need to be oriented is also much smaller.

[0043] (3) The traditional attitude control method requires both flywheels and CMG actuators to control the attitude of the satellite platform, and the antennas and sails on it are also equipped with directional mechanisms; while the use of a product of the present invention can achieve load pointing control. When the attitude-sensitive loads and sensors are located on the moving platform, the remaining auxiliary equipment such as the power supply system, thermal control system, data transmission system, measurement and control system, etc. that do not have high attitude requirements can be arranged on the satellite platform. At this time, the attitude requirements for the satellite platform can be relaxed. Even if there are still directional requirements for antennas and sails, they can also achieve their own directional function through the coordinated movement of their respective driving mechanisms. It can be seen that this patent will use the satellite platform as a large inertia basis, directly use the patented product to drive the attitude maneuvering and stabilization of the load, and let the antennas and sails that need to be oriented move in coordination, which can reduce the response speed and accuracy of the platform attitude control system, reduce the configuration requirements of the attitude control system, and is particularly suitable for today's rapidly developing medium and small satellites.

[0044] (4) The traditional attitude control method relies on the angular momentum exchange of actuators such as flywheels to drive the entire satellite to rotate. However, the angular momentum exchange rate is slow and the inertia of the entire satellite is large, so the acceleration of the entire satellite is small and the starting speed is slow. Directly using the patented direct-drive load, because the load's rotational inertia is small; and the parallel mechanism has a high bandwidth and a fast maneuvering speed, the maneuvering speed of the load can be quickly increased to a faster angular velocity, which can achieve faster attitude maneuvering of the load and other controls.

[0045] If the satellite system is not equipped with a service platform attitude actuator, although the satellite service platform will produce a certain rotation, its angular velocity is much slower, and the attitude error of the satellite service platform only depends on the rotational inertia and bias angular momentum of the service platform. If the attitude requirements of the service platform are not high, attitude control can be omitted; if the attitude requirements of the platform are high or the maneuvering angle of the payload is large, the actuator can be used for attitude control. Although the maneuvering speed of the satellite platform is slower than that of the payload, it can follow the attitude maneuver of the payload. Through the asynchronous maneuvering of the payload and the satellite platform, the agile maneuvering of the payload and the slow maneuvering of the platform are realized, and the range of activities of the parallel mechanism is released for the attitude maneuvering of the payload; and the slow maneuvering of the platform is conducive to the stable control of flexible structures such as solar panels, and it is easier to achieve rapid stability of the satellite platform. It can be seen that this patent does not rely on the maneuvering ability of attitude actuators such as flywheels or CMGs, but can significantly shorten the maneuvering time of the payload. Therefore, the present invention overcomes the shortcomings of low bandwidth and slow speed of traditional methods, and is a truly ultra-agile attitude actuator.

[0046] (5) Traditionally, the attitude of a payload is indirectly controlled by driving the attitude movement of the payload through the attitude control of the satellite platform, and its attitude accuracy cannot be too high. The magnetic levitation super-platform described in this patent has a certain attitude adjustment function, and the attitude of the payload on the platform follower parallel mechanism can be adjusted to the range of the payload release. Through the coarse and fine two-level attitude adjustment, the absolute pointing precision of the payload can be achieved.

[0047] (6) This patent adopts an active and passive integrated magnetic suspension structure with permanent magnets and voice coil motors in parallel, which can not only isolate the vibration transmission between the load and the platform, but also fine-tune the posture of the load with the voice coil motor, so as to achieve ultra-precise and ultra-stable absolute pointing of the load. Different from the traditional active and passive structure of three supers that rely on voice coil motors and membrane springs, the physical contact of the membrane spring will transmit some low-frequency vibrations; this patent is also different from the traditional pure active form of double supers that rely on voice coil motors, which requires constant detection and control. When the posture is not actively adjusted and the vibration is not actively suppressed, the magnetic suspension state between the load and the platform can be maintained with less control, and the transmission of vibration can still be physically blocked, so it is more energy-saving and efficient.

[0048] (7) Traditional satellites generally carry out active vibration isolation for actuators such as flywheels and CMGs. If the requirements for the accuracy, stability and quietness of the payload are higher, passive vibration isolation can be carried out for the payload again. Although two-stage vibration isolation is also achieved, the system is complex and the weight and other costs are relatively high. The parallel mechanism magnetic suspension super platform in this patent itself has a two-stage raft vibration isolation function, that is, its parallel mechanism constitutes passive vibration isolation, and the magnetic suspension super platform constitutes active and passive integrated vibration isolation; and the magnetic suspension static platform has a certain mass and moment of inertia, so the vibration of the payload can be transmitted to the magnetic suspension static platform through the voice coil motor; thereby achieving ultra-quiet vibration of the payload, and there are no sensors and payloads sensitive to micro-vibration on the static platform, so it is an ideal kinetic energy container. At the same time, the voice coil motor provides force and torque for active vibration control, and when necessary (such as during rapid maneuvers), a certain damping can be provided by the closed magnetic damping coil to achieve ultra-precision, ultra-stability and ultra-quiet. It can be seen that this patent is guided by the payload target and can achieve ultra-stable and ultra-quiet performance of the payload in a higher sense.

[0049] (8) This patent realizes passive magnetic suspension of the load through the repulsive force of the permanent magnet. The closer the distance between the dynamic and static platforms is, the greater the repulsive force is. When the distance is very close, the repulsive force is also very large, which can play the role of non-contact limiting. It is obviously different from the traditional spring or hard structure limiting. It not only realizes physical isolation, but also realizes the limiting of the dynamic and static platforms. It can be seen that the structure of the present invention is simpler and can effectively prevent collision and impact.

[0050] (9) The present invention uses the parallel mechanism super-platform of the present invention to borrow force from the spacecraft platform to achieve direct drive load attitude maneuvering and stabilization. The force and torque during the maneuvering process are transmitted through the nut screw, and the non-maneuverable branch chain is locked by using the radial transmission and self-locking of the nut screw. The main torque and other loads are transmitted to the platform through the screw, so the product has better mechanical stability and mechanical resistance. In addition, the parallel mechanism has higher support stiffness and positioning accuracy.

[0051] Specifically, Figures 1 to 5 As shown, an embodiment of the present invention provides an active-passive integrated magnetic levitation five-superload platform 1 based on a parallel mechanism, comprising a parallel mechanism frame 4 and a magnetic levitation super platform 5 connected to each other, the parallel mechanism frame 4 is also connected to a satellite body 3, and the magnetic levitation super platform 5 is also connected to a load 2;

[0052] The parallel mechanism frame 4 includes a plurality of branches for providing posture maneuverability for the magnetic levitation super platform 5. The magnetic levitation super platform 5 includes a magnetic levitation isolator 15, a voice coil motor, a magnetic levitation moving platform 18 and magnetic damping. The magnetic levitation moving platform 18 is used to install the load 2. The voice coil motor is respectively connected to the magnetic levitation moving platform 18 and the parallel mechanism frame 4 to provide the ability to actively adjust the magnetic levitation moving platform 18. The magnetic levitation isolator 15 is used to reduce vibration during movement.

[0053] In this embodiment, the payload 2 may be an optical camera, radar, laser communication equipment, or other effective payload 2. The payload 2 is equipped with an absolute attitude sensor such as a star sensor, a high-dynamic gyroscope, and an acceleration sensor. The parallel mechanism frame 4 can be set to a three-branch, four-branch, or other multi-branch parallel mechanism according to the task requirements such as the number of degrees of freedom of the agile attitude maneuvering of the satellite payload 2, mainly to achieve a large range of attitude maneuvers of its moving platform, and provide a large range of super-agile attitude maneuvering capabilities for the magnetic levitation super platform 5. Among them, the three-branch platform "super" platform such as Figure 3 As shown. The platform can achieve a three-axis maneuvering range better than ±45°, and the maneuvering range can be further increased through configuration design, which can meet the maneuvering requirements of most payloads 2. The magnetic suspension dynamic platform 18 provides a mounting interface for payload 2, and provides a small range of posture fine adjustment and micro-vibration isolation for payload 2, creating an ultra-precise, ultra-stable and ultra-quiet working environment for the stable operation of payload 2.

[0054] In some embodiments of the present invention, the parallel mechanism frame 4 includes a parallel mechanism base 6, a grating code disk 7, a rotary motor 8, a lead screw 9, a nut 10, a damping rod 11, a hinge 12, a parallel mechanism moving platform 13 and an electric cylinder 14;

[0055] The parallel mechanism frame 4 adopts a 3-PURU / 1-PRU or 3-PURU / 1-RU multi-branch parallel configuration to enable the parallel mechanism frame 4 to achieve three-axis rotational freedom and large-angle rotation. The parallel mechanism base 6 is a triangle, and its three vertices are each provided with two groups of rotating motors 8 and grating code disks 7, and its three sides are provided with lead screws 9. Each group of rotating motors 8 and grating code disks 7 is connected to one end of a lead screw 9 to control the lead screw 9 to rotate according to a preset number of turns. One end of the damping rod 11 is threadedly connected to the lead screw 9 through a nut 10, and the other end is connected to the parallel mechanism moving platform 13 through a hinge 12. The parallel mechanism moving platform 13 is connected to the magnetic suspension moving platform 18 through a voice coil motor and a magnetic suspension vibration isolator 15. The electric cylinder 14 is arranged in the middle of the parallel mechanism base 6;

[0056] The lead screw 9 is driven to rotate by the rotating motor 8, pushing the nut 10 to translate, and then the dynamic parallel mechanism dynamic platform 13 is rotated through the hinge 12, finally realizing the direction of the magnetic levitation super platform 5 at any continuous angle in the local area, and realizing the three-axis large-range attitude maneuvering of the load 2.

[0057] In this embodiment, 3-PURU / 1-PRU is used for illustration.

[0058] In some embodiments of the present invention, the damping rod 11 is composed of a spring damper and is used to passively isolate medium and high frequency vibrations on the satellite, that is, to first isolate the vibrations transmitted from the satellite platform to the magnetic suspension super platform 5 to a certain extent.

[0059] In some embodiments of the present invention, the parallel mechanism frame 4 includes structural damping, which is used to dissipate the energy of local resonance and improve the ultra-stable and ultra-quiet performance of the load 2.

[0060] In some embodiments of the present invention, the magnetic suspension vibration isolator 15 supports the magnetic suspension moving platform 18 and the parallel mechanism moving platform 13 contactlessly through the repulsive force of the permanent magnet, so as to limit the relative position of the two within a certain range, thereby forming a passive vibration isolation system. When the relative position changes, the repulsive force will automatically return to the vicinity of the equilibrium point. If the system is designed to be completely symmetrical, balance and low-rigidity support can be achieved with the assistance of the active force.

[0061] In some embodiments of the present invention, the magnetic levitation vibration isolator 15 includes a mounting rod 19, a mounting sleeve 20, a first axial permanent magnet 21, a second axial permanent magnet 22, a magnetic isolation ring 23, an inner radiating permanent magnet 24, an outer radiating permanent magnet 25, a sleeve 26, and a locking ring 27. The interior of the mounting sleeve 20 is a sleeve 26, and the middle of the sleeve 26 is provided with a first axial permanent magnet 21. Two second axial permanent magnets, two magnetic isolation rings 23, two inner radiating permanent magnets 24, two outer radiating permanent magnets 25, and two locking rings 27 are respectively arranged on both sides of the first axial permanent magnet 21. The mounting rod 19 is connected to the magnetic levitation moving platform 18, and the mounting sleeve 20 is connected to the parallel mechanism moving platform 13.

[0062] The magnetic levitation isolator 15 uses the repulsive force of permanent magnets to support the magnetic levitation moving platform 18, and limits the relative position of the magnetic levitation moving platform 18 and the parallel mechanism moving platform 13 within a certain range. The system constitutes a passive vibration isolation system. When the relative position changes, the repulsive force will automatically return to the vicinity of the equilibrium point. If the system is designed to be completely symmetrical, balance and low-rigidity support can be achieved with the assistance of the main force.

[0063] In some embodiments of the present invention, a voice coil motor is used to provide force and torque in 6 degrees of freedom.

[0064] In some embodiments of the present invention, a displacement sensor is connected in parallel to the axial direction of each voice coil motor to detect the relative axial position change of the voice coil motor.

[0065] The active magnetic levitation system composed of the voice coil motor can not only adjust the posture of the upper platform within a certain range, thereby achieving ultra-precise and ultra-stable pointing of payload 2; it can also control the vibration of the upper platform and actively transmit the vibration to the lower platform, thereby achieving ultra-quietness of the upper platform and creating a better environment for payload 2.

[0066] A damping coil that can be switched on and off is set inside the voice coil motor. When the coil is closed, it provides a certain passive magnetic damping; conversely, when the coil is disconnected, the damping disappears, realizing system damping regulation.

[0067] In some embodiments of the present invention, the stator part of the voice coil motor is fixed to the parallel mechanism moving platform 13 , and the mover part of the voice coil motor is fixed to the magnetic suspension moving platform 18 .

[0068] In some embodiments of the present invention, the voice coil motor includes a first voice coil motor 16 and a second voice coil motor 17, the axes of the first voice coil motor 16 and the second voice coil motor 17 are perpendicular, wherein four first voice coil motors 16 are used to control the axial deflection and axial movement of the magnetic levitation platform 18, and four second voice coil motors 17 are used to control the translation in two horizontal directions and the rotation around the axis.

[0069] The parallel mechanism frame 4 provides passive vibration isolation, which is connected in series with the active and passive integrated magnetic levitation super platform 5 in two stages, which can not only perform coarse and fine adjustment of the posture of the payload 2; but also attenuate the full-band vibration through the two-stage raft, ultimately achieving the "five super" performance of the payload 2, namely, ultra-precision, ultra-stable, ultra-quiet, and ultra-agile.

[0070] Please refer to Figure 6 This patent aims at the "five super" goals and two-level structure. When the posture is agile and maneuverable, a control strategy with the platform as the main and the load following is adopted; when the posture is stable, a control strategy with the load as the main and the platform following is adopted; through master-slave switching control, it can adapt to different working conditions.

[0071] Relative posture control of the payload cabin following the platform cabin

[0072] The traditional control strategy that takes the platform cabin as the main body and the payload cabin as the follower, that is, the active and passive magnetic levitation super-platform only plays a supporting role, but does not play the active fine adjustment function of its posture. The posture of the payload is completely guaranteed by the posture adjustment of the platform cabin. Therefore, it is only necessary to perform relative posture control according to the relative position information of the dynamic and static platforms measured by the displacement sensor in the active and passive magnetic levitation super-platform. That is, the relative posture of the payload cabin relative to the platform cabin estimated by the displacement sensor is used for feedback control to control the dynamic and static platforms to a suitable posture and achieve a fixed support state; the stiffness of the magnetic bearing can be improved by modifying the feedback coefficient.

[0073] The attitude movement of the platform cabin is transmitted by the change in the relative position of the magnetically levitated dynamic and static platforms, and the payload cabin is controlled to follow the movement of the platform cabin to avoid collision between the dynamic and static platforms, thus achieving super-agility in the attitude of the payload cabin.

[0074] Absolute attitude control of the platform cabin following the payload cabin

[0075] Feedback is obtained through absolute attitude sensors such as star sensors and gyroscopes, rapid and large-range coarse attitude adjustment is performed using parallel mechanisms, and high-bandwidth, small-range fine attitude adjustment is performed using active magnetic levitation mechanisms such as voice coil motors. The organic combination of coarse and fine absolute attitude control can achieve both large-range rapid attitude maneuvers of the payload and high-precision pointing stability of the payload's attitude, thereby achieving ultra-precise, ultra-stable and ultra-agile performance of the payload's attitude.

[0076] Through the passive vibration isolation of the parallel mechanism and the two-stage series vibration isolation of the active and passive integrated magnetic suspension, the transmission of vibration can be reduced, and the vibration isolation of the satellite platform can be achieved. The stiffness of the magnetic suspension mechanism is low, so the isolation effect of micro-vibration is better. At the same time, the voice coil motor can actively control the interference generated by the filter wheel in the camera through the feedback of the absolute position sensor such as the accelerometer, star sensor and gyroscope, so as to achieve ultra-quiet load attitude.

[0077] In summary: 1) The application mode of this patent breaks through the traditional attitude control mode, directly drives a smaller load to perform attitude maneuvers and stability, so the maneuvering speed and efficiency are higher, and the configuration requirements of the attitude control system are correspondingly reduced. 2) This patent only drives the load to maneuver, and the platform is almost motionless, so it basically does not break the orientation of the battery array and the antenna, and thus breaks through the traditional load attitude maneuvering, which breaks the attitude stability of the entire satellite and requires the on-board solar battery array drive mechanism, antenna drive mechanism and other directional multi-mechanism coordinated maneuvers. 3) This patent adopts a two-stage floating raft structure based on a passive vibration isolator based on spring damping and an active and passive integrated magnetic suspension structure based on a parallel connection of a permanent magnet and a voice coil motor, which can not only effectively isolate the vibration transmission between the load and the platform, but also the voice coil motor can fine-tune the attitude of the load, realizing the ultra-precision and ultra-stability of the load pointing, breaking through the traditional single-stage vibration isolation mode. Therefore, the invention is targeted at the load attitude, and is expected to truly achieve the "five super" effects of ultra-precision, ultra-stability, ultra-quietness and ultra-agility of the load attitude.

[0078] (1) Examples of application scenarios of parallel mechanism super-platforms

[0079] This patent directly targets the requirements of ultra-precision, ultra-stability, ultra-quietness and ultra-agility of the attitude of payloads on spacecraft such as satellites. It combines relevant technologies such as active and passive magnetic suspension, magnetic damping and parallel mechanisms, and provides "an active and passive integrated magnetic suspension 'super' platform based on a parallel mechanism". It achieves "five super" performances through the organic cooperation of the parallel mechanism and the magnetic suspension super platform. That is, the parallel mechanism is used to directly drive the payload to quickly maneuver the attitude by borrowing force and torque from the satellite platform, so as to achieve large-scale rapid attitude maneuvering and stable control of the payload; the active and passive integrated magnetic suspension is used to achieve small-scale high-precision attitude control of the payload, and the coarse and fine two-level absolute attitude coordinated control can achieve ultra-precision, ultra-stability, ultra-quietness and ultra-agility of the payload; and this patent only drives the payload to maneuver, while the platform is almost motionless, so it basically does not break the orientation of the battery array and the antenna. On the other hand, this patent adopts active and passive two-stage floating raft vibration isolation on the transmission path, and the load side vibration isolation adopts active and passive integrated magnetic suspension, which realizes complete physical isolation of the dynamic and static platform in both active and passive states, which is more conducive to vibration isolation. In short, this patent adapts to the current trend of high-precision, large-range, stable sensitivity or impact of loads.

[0080] It can be seen that this patented product can be used as an ultra-quiet test platform on spacecraft, and can also be used for large-scale rapid attitude maneuvers and ultra-precise, ultra-stable and ultra-quiet pointing of payloads such as cameras, and can also be used as an ultra-quiet test platform on spacecraft; it can also be used as a fast, high-precision and high-stable strike platform for satellite-borne and ship-borne laser weapons, and it has strong versatility, a wide range of application fields and good application prospects. It is especially suitable for today's rapidly developing medium and small satellites.

[0081] This patent can serve as a new direction for the development of subsequent load attitude adjustment mechanisms. It is a universal ultra-precise, ultra-stable, ultra-quiet, ultra-agile and ultra-wide pointing platform for loads, with high application prospects and application value.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An active and passive integrated magnetic levitation five-superload platform based on a parallel mechanism, characterized in that: It comprises a parallel mechanism frame (4) and a magnetic suspension super platform (5) which are connected to each other, wherein the parallel mechanism frame (4) is also connected to a satellite body (3), and the magnetic suspension super platform (5) is also connected to a load (2); The parallel mechanism frame (4) includes a plurality of branches for providing the magnetic suspension super platform (5) with posture maneuverability. The magnetic suspension super platform (5) includes a magnetic suspension vibration isolator (15), a voice coil motor, a magnetic suspension dynamic platform (18) and magnetic damping. The magnetic suspension dynamic platform (18) is used to install the load (2). The voice coil motor is respectively connected to the magnetic suspension dynamic platform (18) and the parallel mechanism frame (4) to provide the ability to actively adjust the magnetic suspension dynamic platform (18). The magnetic suspension vibration isolator (15) is used to reduce vibration during movement.

2. The load platform according to claim 1, characterized in that: The parallel mechanism frame (4) comprises a parallel mechanism base (6), a grating code disk (7), a rotary motor (8), a lead screw (9), a nut (10), a damping rod (11), a hinge (12), a parallel mechanism moving platform (13) and an electric cylinder (14); The parallel mechanism frame (4) adopts a 3-PURU / 1-PRU or 3-PURU / 1-RU multi-branch parallel configuration, so that the parallel mechanism frame (4) can achieve three-axis rotational freedom and large-angle rotation. The parallel mechanism base (6) is a triangle, and its three vertices are each provided with two groups of rotating motors (8) and the grating code disk (7), and its three sides are provided with lead screws (9). Each group of the rotating motors (8) and the grating code disk (7) is connected to one of the One end of the lead screw (9) is used to control the lead screw (9) to rotate according to a preset number of turns, one end of the damping rod (11) is threadedly connected to the lead screw (9) through a nut (10), and the other end is connected to the parallel mechanism moving platform (13) through a hinge (12), the parallel mechanism moving platform (13) is connected to the magnetic suspension moving platform (18) through the voice coil motor and the magnetic suspension vibration isolator (15), and the electric cylinder (14) is arranged in the middle of the parallel mechanism base (6); The lead screw (9) is driven to rotate by a rotating motor (8), pushing the nut (10) to translate, and then the dynamic parallel mechanism dynamic platform (13) is rotated by a hinge (12), and finally the direction of the magnetic suspension super platform (5) is directed to any continuous angle in a local area, thereby realizing the three-axis large-range attitude maneuvering of the load (2).

3. The load platform according to claim 2, characterized in that: The damping rod (11) is composed of a spring damper and is used to passively isolate medium and high frequency vibrations on the satellite, that is, to first isolate the vibrations transmitted from the satellite platform to the magnetic suspension super platform (5) to a certain extent.

4. The load platform according to claim 2, characterized in that: The parallel mechanism frame (4) includes structural damping, which is used to dissipate the energy of local resonance and improve the ultra-stable and ultra-quiet performance of the load (2).

5. The load platform according to claim 2, characterized in that: The magnetic suspension vibration isolator (15) supports the magnetic suspension moving platform (18) and the parallel mechanism moving platform (13) contactlessly through the repulsive force of the permanent magnet, so as to limit the relative positions of the two within a certain range, thereby forming a passive vibration isolation system.

6. The load platform according to claim 5, characterized in that: The magnetic suspension vibration isolator (15) comprises a mounting rod (19), a mounting sleeve (20), a first axial permanent magnet (21), a second axial permanent magnet (22), a magnetic isolation ring (23), an inner radiating permanent magnet (24), an outer radiating permanent magnet (25), a sleeve (26), and a locking ring (27); the mounting sleeve (20) contains the sleeve (26); a first axial permanent magnet (21) is arranged in the middle of the sleeve (26); two of the second axial permanent magnets, two of the magnetic isolation rings (23), two of the inner radiating permanent magnets (24), two of the outer radiating permanent magnets (25), and two of the locking rings (27) are arranged on both sides of the first axial permanent magnet (21) in sequence; the mounting rod (19) is connected to the magnetic suspension moving platform (18); and the mounting sleeve (20) is connected to the parallel mechanism moving platform (13).

7. The load platform according to claim 2, characterized in that: The voice coil motor is used to provide force and torque with 6 degrees of freedom.

8. The load platform according to claim 7, characterized in that: A displacement sensor is connected in parallel to the axial direction of each voice coil motor to detect the relative axial position change of the voice coil motor.

9. The load platform according to claim 7, characterized in that: The stator part of the voice coil motor is fixed to the parallel mechanism moving platform (13), and the mover part of the voice coil motor is fixed to the magnetic suspension moving platform (18).

10. The load platform according to claim 7, characterized in that: The voice coil motor comprises a first voice coil motor (16) and a second voice coil motor (17), wherein the axes of the first voice coil motor (16) and the second voice coil motor (17) are perpendicular, wherein four of the first voice coil motors (16) are used to control the axial deflection and axial movement of the magnetic levitation platform (18), and four of the second voice coil motors (17) are used to control the translation in two horizontal directions and the rotation around the axis.

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