CN111551330B

CN111551330B - Four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system

Info

Publication number: CN111551330B
Application number: CN202010435464.0A
Authority: CN
Inventors: 杈硅竟; 边边
Original assignee: Beijing Hangyu Zhenkong Technology Co ltd
Current assignee: Beijing Hangyu Zhenkong Technology Co ltd
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2021-07-23
Anticipated expiration: 2040-05-21
Also published as: CN111551330A

Abstract

The invention discloses a four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system, which adopts a four-stage Stewart mechanism six-degree-of-freedom parallel configuration and comprises twenty-four actuator branches, a plurality of air spring branches, a plurality of auxiliary support branches, an upper platform assembly, a lower platform assembly and a real-time control hardware system; the upper platform assembly and the lower platform assembly are connected by twenty-four actuator branches, air spring branches and auxiliary support branches; each actuator branch is composed of a linear moving magnet type motor, a hinge assembly and an adapter piece; each air spring branch is composed of an air spring and an adapter; each auxiliary support branch is composed of a threaded screw rod lifter and an adapter; the real-time control hardware system obtains six-degree-of-freedom displacement and acceleration signals of the upper platform collected by the sensor through A/D sampling, and control signals are calculated; the control signal is output to the power amplifier through the D/A, the drive actuator outputs axial motion, and the upper platform is pushed to generate a desired six-degree-of-freedom vibration excitation signal.

Description

Four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system

Technical Field

The invention belongs to the field of vibration control of intelligent parallel mechanisms, and particularly relates to a four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system which can be used for simulating vibration signals received by a precision instrument in various environments.

Background

The high-precision load, the precision instrument and the like are inevitably interfered by mechanical vibration from a carrying tool or the outside in the task execution process, and the characteristics of multi-degree-of-freedom linear-angular vibration coupling, coexistence of high-frequency vibration and low-frequency vibration and the like are presented, so that the control precision and the stability level of the equipment are greatly influenced, and therefore, the working state of the equipment under the multi-degree-of-freedom complex vibration interference and debugging under the laboratory (internal field) environment have important engineering significance.

The typical equipment used for providing vibration signals for a test piece is a vibration table, the vibration table with single degree of freedom is widely applied at present, but the vibration table can only provide vibration signals of single-axis translation or single-axis rotation through tool switching, and with the improvement of engineering technology and the improvement of the recognition level of a vibration environment, the vibration simulation with single degree of freedom can not meet the test requirements of high-precision loads, precision instruments and the like increasingly. At present, the vibration simulation equipment with multiple degrees of freedom still has few research and development results, and has few practical applications in various fields. Therefore, the development of the vibration simulation system with multiple degrees of freedom has important practical significance.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the problem that a single-degree-of-freedom vibration table cannot meet the test requirement of multi-degree-of-freedom vibration simulation easily, a novel six-degree-of-freedom vibration excitation system is provided, and can be used for synchronously simulating vibration signals with at most six degrees of freedom, providing multi-degree-of-freedom vibration excitation in complex environments such as satellite-borne, missile-borne, airborne, ship-borne or vehicle-borne test pieces (high-precision loads, precision instruments and the like) so as to test the stability level and the control precision of the test pieces in the complex vibration interference environment, or testing and calibrating the functional performance and the like.

The technical scheme adopted by the invention for solving the technical problems is as follows: a six-degree-of-freedom vibration excitation system with a four-stage Stewart mechanism parallel configuration adopts a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, and comprises twenty-four actuator branches, a plurality of air spring branches, a plurality of auxiliary support branches, an upper platform assembly, a lower platform assembly and a real-time control hardware system;

the mechanism configuration of the system is a four-stage Stewart mechanism six-degree-of-freedom parallel configuration, twenty-four actuator branches are divided into four groups, the layout mode of each group in space is the Stewart configuration, and the four groups of Stewart configurations form the four-stage Stewart mechanism six-degree-of-freedom parallel configuration in a parallel mode;

the six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is as follows:

the twenty-four actuator branches are divided into four groups, and each group of six actuators forms a classic Stewart configuration mechanism; the upper table top of each Stewart classical configuration is a horizontal plane; the four Stewart configuration mechanisms are positioned on the same horizontal plane height, the centers of the upper table tops of the four Stewart configuration mechanisms form a quadrangle, the center of the upper table top of the whole Stewart configuration mechanism is positioned in the quadrangle, the layout mode is that the centers of the upper table tops of the four Stewart configuration mechanisms are rotationally symmetrical around the Z axis of the center of the whole Stewart configuration mechanism, namely the centers of the upper table tops of the four Stewart classic configurations and the center of the upper table top of the whole Stewart configuration mutually form an included angle of 90 degrees in the direction of the connecting line, and the centers of the upper table tops of the four Stewart classic configurations are completely overlapped after rotating for 90 degrees around the Z axis of the center of the whole Stewart configuration mechanism; the centers of the upper table tops of the four Stewart classical configurations are on a circle which takes the center of the whole upper table top as the center of a circle and takes a certain distance as the radius; the four Stewart classical configurations belong to a four-stage parallel relation with respect to the configuration of the whole system, and are called four-stage Stewart mechanism six-degree-of-freedom parallel configurations;

the actuator branches each comprise a set of precise hinge components, an actuator and a relevant connecting piece thereof; the hinge assembly comprises a two-degree-of-freedom hinge and a three-degree-of-freedom hinge and has five-degree-of-freedom rotation; the two-degree-of-freedom hinge comprises a cross shaft, two pairs of rolling bearings and related connecting pieces thereof to form a two-degree-of-freedom hooke hinge, and the three-degree-of-freedom hinge comprises a vertical shaft, a universal ball hinge and related connecting pieces thereof to form a three-degree-of-freedom rotating hinge; the actuator is a linear moving magnet type motor consisting of a moving coil and a fixed magnet assembly, and has the capability of outputting electromagnetic actuating force to further control the linear motion of the moving coil along the axial direction; the hinge assembly is connected with the actuator through the adapter plate to form an actuator assembly, and the actuator assembly is connected with the upper platform through the upper hinge base and is connected with the lower platform assembly through the lower connecting block;

each air spring branch comprises an air spring and a related connecting piece thereof, and generates corresponding vertical supporting force for the connected upper table top;

each auxiliary support branch comprises a threaded screw rod lifter, an S-shaped force sensor and a relevant connecting piece thereof, and generates corresponding vertical support force on the upper table-board in an inflated or non-working state;

the real-time control hardware system comprises a high-speed control computer, a multi-channel A/D data acquisition card, a multi-channel D/A data output card, a power amplifier, an acceleration sensor, a force sensor, a displacement sensor, a signal conditioner and a sensor tool; the system comprises an acceleration sensor, a multi-channel A/D data acquisition card, a multi-channel D/A data output card, a sensor and a matched signal conditioner, wherein the acceleration sensor is arranged on an upper platform assembly through a sensor tool, the force sensor is arranged on an auxiliary support system branch through a connecting piece, a displacement sensor is arranged on an actuator branch through the sensor tool, the multi-channel A/D data acquisition card and the multi-channel D/A data output card are arranged in a high-speed control computer case, the A/D acquisition card is connected with the sensor and the matched signal conditioner through a shielding wire and a junction box, the D/A data output card is connected with a power amplifier through a; the acceleration sensor is used for measuring six-degree-of-freedom acceleration of the upper platform, the six-degree-of-freedom acceleration is used as a feedback signal through the signal conditioner and the multi-channel A/D data acquisition card, a control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is generated through resolving by the high-speed control computer, a driving signal is generated through the multi-channel D/A data output card and the power amplifier, and then the actuator is controlled to output axial motion, so that the upper platform assembly is pushed to generate an expected simulated vibration signal; the force sensor is used for measuring the supporting force of the auxiliary supporting system on the upper table top, the supporting force is used as a feedback signal through the multichannel A/D data acquisition card, a control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is generated through resolving through the high-speed control computer, and an air charging and discharging control signal is generated through the multichannel D/A data output card to control the air charging and discharging process of each air spring branch; the displacement sensor is used for measuring the position of each actuator branch motor, the position is used as a feedback signal through the signal conditioner and the multi-channel A/D data acquisition card, a high-speed control computer is used for resolving to generate a displacement closed-loop control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, the displacement closed-loop control signal is generated through the multi-channel D/A data output card and the power amplifier, and then the position of each actuator is controlled to be stable near the central position, so that the safety and the stability of the upper platform assembly are kept.

Furthermore, the configuration is a four-stage Stewart mechanism six-degree-of-freedom parallel configuration and comprises four classical single-stage Stewart configurations which are connected in parallel; the classic single-stage Stewart structure comprises an upper table top, a lower table top, 6 actuator branches and an air spring branch or an auxiliary support branch, wherein each actuator branch is connected with the upper table top through an upper hinge point, each actuator branch is connected with the lower table top through a lower hinge point, and six upper hinge points and six lower hinge points are respectively distributed on an envelope circle of the upper table top and an envelope circle of the lower table top; every two adjacent upper hinge points are divided into one group, three groups in total, the included angle formed by each group of upper hinge points and the center of the upper table top is the same, every two adjacent lower hinge points can be divided into one group, three groups in total, and the included angle formed by each group of lower hinge points and the center of the lower table top is the same; in the classic single-stage Stewart configuration, the direction of the center of the upper table top pointing to the midpoint of a group of upper hinge points is the positive direction of an X axis, the direction of the center of the lower table top pointing to the center of the upper table top is the positive direction of a Z axis, and a right-hand coordinate system is met;

the arrangement directions of the four classical single-stage Stewart configurations are provided with four implementation modes:

the implementation mode 1 is a rotational symmetry implementation mode that the forward direction of the X axis of each classical single-stage Stewart configuration points to the opposite direction of the connecting line of the center of the upper table top of each classical single-stage Stewart configuration and the center of the upper table top of the whole table, namely the forward direction of the X axis of each single stage is outward;

the implementation mode 2 is a rotational symmetry implementation mode that the positive direction of the X axis of each classical single-stage Stewart configuration points to the direction of a connecting line between the center of the upper table top of each classical single-stage Stewart configuration and the center of the upper table top of the whole table, namely the positive direction of the X axis of each single stage is inward;

the implementation mode 3 is a rotational symmetry implementation mode that the positive directions of X axes of four classical single-stage Stewart configurations are the same, namely the directions of the single-stage X axes are the same;

the implementation mode 4 is an axial symmetry implementation mode that the positive directions of the X axes of the two classical single-stage Stewart configurations on one side are opposite to the positive directions of the X axes of the two classical single-stage Stewart configurations on the other side and are symmetrical about a certain axis, namely the directions of the X axes of the single stages on the two sides are opposite.

Furthermore, the actuator branch circuits are divided into twenty-four branch circuits, the actuator branch circuits are used for providing accurate and controllable output force for the system, and each branch circuit comprises an actuator, a hinge assembly, an adapter plate and a lower connecting block; the hinge assembly comprises a spherical hinge base, a spherical hinge ball head, a spherical hinge upper connecting piece, a middle U-shaped fork and an upper U-shaped fork; each part forms twenty-four actuator branch circuits in the following connection mode:

the spherical hinge base and the spherical hinge ball head are installed in a matched mode through outer hexagonal screws, the spherical hinge ball head and a connecting piece on the spherical hinge are installed through threads, the connecting piece on the spherical hinge and the middle U-shaped fork are installed in parallel through the outer hexagonal screws, and the middle U-shaped fork and the upper U-shaped fork are installed vertically through a cross shaft, two pairs of rolling bearings and the outer hexagonal screws to form a hinge assembly 1; a spherical hinge base in the hinge assembly 1 is connected with an actuator moving coil through an adapter plate, and the connection line of the rotational centers of all degrees of freedom of the hinge assembly is ensured to be matched with the axis of the moving coil through a positioning hole; the lower connecting block is arranged at the bottom of the actuator through an inner hexagon screw and is positioned with a positioning hole at the bottom of the actuator through a positioning pin;

the twenty-four actuator branch circuits are installed in the same mode, connected with the upper platform assembly through the positioning pins and connected with the lower platform assembly through the lower connecting block to form a mechanical motion part of the six-degree-of-freedom vibration simulation system.

Furthermore, the air spring branches are divided into sixteen air spring branches, or the number of the air spring branches is increased or decreased according to the capacity of the selected air spring model and the actual load weight of the whole air spring, so that the supporting force for offsetting the gravity is provided for the moving part of the system in work, the four air spring branches are in a group in a layout mode and are distributed in a quadrilateral mode, and each group of air spring branches can support a single-stage Stewart classical configuration;

the sixteen air spring branches are installed in the same mode and are respectively connected with the upper platform assembly and the lower platform assembly through outer hexagon screws, and an air spring supporting part of the six-freedom-degree vibration simulation system with the supporting force adjusting function is formed.

Furthermore, the auxiliary support branches are divided into twelve branches in a typical design, or the number of the auxiliary support branches is increased or decreased according to the capacity of the selected auxiliary support part and the actual load weight of the whole support, so that the auxiliary support branches have the functions of providing support force for counteracting gravity for the system motion part at the end of the test and during automatic inflation, and the support force provided during automatic inflation is input into the automatic inflation control system as a feedback signal, the layout mode is that three auxiliary support branches are in a group and are distributed in a triangular shape, and each group of auxiliary support branches can realize the support of a single-stage Stewart classical configuration;

twelve auxiliary support branches are mounted in the same manner, are connected with the upper platform assembly through the positioning blocks and are connected with the lower platform assembly through the outer hexagon screws, and an auxiliary support part of the six-degree-of-freedom vibration simulation system for providing support force and feeding back support force signals is formed.

Furthermore, the upper platform assembly is used for providing a rigid mechanical mounting table for the test piece and observing the simulated vibration signal through the measured acceleration signal; the device comprises an upper platform, twelve upper hinge seats, a central sensor seat, a side sensor seat and six acceleration sensors; twelve positioning grooves are formed in the edge of the lower surface of the upper platform and are respectively connected with twelve upper hinge seats; the central sensor seat is arranged at the center of the lower surface of the upper platform, is respectively connected with the sensor 1, the sensor 2 and the sensor 3 through three mounting holes and is used for measuring the translational acceleration of the upper platform along X, Y and Z axes; the sensor 4 is connected to the intersection of the Y axis and the reinforcing rib on the lower surface of the upper platform through a stud and is used for measuring the rotation acceleration of the upper platform around the X axis; the side sensor seat is arranged at the intersection of the X axis of the lower surface of the upper platform and the reinforcing rib, is connected with the sensor 5 and the sensor 6 through two mounting holes and is used for measuring the rotation acceleration of the upper platform around the Y, Z axis.

Furthermore, lower platform subassembly, its effect be for the system provides stable installation basis to link firmly with the ground through rag screw, transmit the vibration isolation ground with the vibration transmission of system self, protect peripheral equipment.

The invention has the advantages that:

(1) the invention designs a six-degree-of-freedom vibration excitation system which has six-degree-of-freedom motion capability under load and can generate vibration excitation signals with at most six degrees of freedom;

(2) the invention designs a novel six-degree-of-freedom parallel mechanism configuration, namely a four-stage Stewart mechanism six-degree-of-freedom parallel configuration, and the six-degree-of-freedom parallel mechanism arranged according to the configuration has larger working space and larger load capacity; the former means that under the condition of selecting the same actuator, the system can obtain larger translation and rotation space; the latter means that the upper platform of the system can be designed to be larger in size, and the air spring branches and the auxiliary supporting branches can provide additional supporting force for offsetting the gravity of the load, so that the system has larger bearing capacity, and the load size can be larger;

(3) the invention forms an actuating mechanism taking the linear moving magnet type motor as the center, has simple and firm structure and has the advantages of good output linearity, quick response, high reliability and the like of the linear moving magnet type motor;

(4) in addition to the larger size of the upper platform, other mechanical parts such as the designed hinge assembly and the like can bear the gravity with larger load, so that the four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system has larger loadable load mass, and further has larger bearing capacity and higher working bandwidth.

Drawings

FIG. 1 is an isometric view of the present invention;

FIG. 2 is a schematic diagram of a four-stage Stewart mechanism six-degree-of-freedom parallel configuration;

FIG. 3 is a top view of a four-stage Stewart mechanism six degrees of freedom parallel configuration implementation 1 of the present invention;

FIG. 4 is a top view of a four-stage Stewart mechanism six degrees of freedom parallel configuration implementation 2 of the present invention;

FIG. 5 is a top view of a four-stage Stewart mechanism six degrees of freedom parallel configuration implementation 3 of the present invention;

FIG. 6 is a top view of a four-stage Stewart mechanism six degrees of freedom parallel configuration implementation 4 of the present invention;

FIG. 7 is a front view of the present invention;

FIG. 8 is a rear view of the present invention;

FIG. 9 is a top view of the lower platform assembly 1 of the present invention;

FIG. 10 is a left side view of the actuator arm 1 of the present invention;

FIG. 11 is an isometric view of an air spring bypass arrangement of the present invention;

FIG. 12 is an isometric view of an arrangement of secondary support legs of the present invention;

FIG. 13 is a bottom plan view of the upper platform assembly of the present invention;

FIG. 14 is a control loop block diagram of the real-time control hardware system of the present invention.

In the figure:

10000-lower platform assembly 20100-actuator branch 120200-actuator branch 2

20300 actuator branch 320400 actuator branch 420500 actuator branch 5

20600-actuator Branch 620700-actuator Branch 720800-actuator Branch 8

20900-actuator Branch 921000-actuator Branch 1021100-actuator Branch 11

21200 actuator branch 1221300 actuator branch 1321400 actuator branch 14

21500 actuator Branch 1521600 actuator Branch 1621700 actuator Branch 17

21800-actuator branch 1821900-actuator branch 1922000-actuator branch 20

22100 actuator branch 2122200 actuator branch 2222300 actuator branch 23

22400, actuator branch 2430100, air spring branch 130200 and air spring branch 2

30300 air spring branch 330400 air spring branch 430500 air spring branch 5

30600 air spring branch 630700 air spring branch 730800 air spring branch 8

30900 air spring branch 931000 air spring branch 1031100 air spring branch 11

31200 air spring branch 1231300 air spring branch 1331400 air spring branch 14

31500 air spring branch 1531600 air spring branch 1640100 auxiliary support branch 1

40200 auxiliary support branch 240300 auxiliary support branch 340400 auxiliary support branch 4

40500 auxiliary support branch 540600 auxiliary support branch 640700 auxiliary support branch 7

40800 auxiliary supporting branch 840900 auxiliary supporting branch 941000 auxiliary supporting branch 10

41100 auxiliary support branch 1141200 auxiliary support branch 1250000 upper platform assembly

10101 lower platform

20101, actuator 120201, actuator 220301 and actuator 3

20401-actuator 420501-actuator 520601-actuator 6

20701, actuator 720801, actuator 820901, actuator 9

21001 actuator 1021101 actuator 1121201 actuator 12

21301 actuator 1321401 actuator 1421501 actuator 15

21601-actuator 1621701-actuator 1721801-actuator 18

21901-actuator 1922001-actuator 2022101-actuator 21

22201-actuator 2222301-actuator 2322401-actuator 24

20102, lower connecting block 120202, lower connecting block 220302 and lower connecting block 3

20402-lower connecting block 420502-lower connecting block 520602-lower connecting block 6

20702, lower connecting block 720802, lower connecting block 820902 and lower connecting block 9

21002-lower connecting block 1021102-lower connecting block 1121202-lower connecting block 12

21302-lower connecting block 1321402-lower connecting block 1421502-lower connecting block 15

21602-lower connecting block 1621702-lower connecting block 1721802-lower connecting block 18

21902-lower connecting block 1922002-lower connecting block 2022102-lower connecting block 21

22202-lower connecting block 2222302-lower connecting block 2322402-lower connecting block 24

20103-adapter plate 120203-adapter plate 220303-adapter plate 3

20403-adapter plate 420503-adapter plate 520603-adapter plate 6

20703, adapter plate 720803, adapter plate 820903 and adapter plate 9

21003-adapter plate 1021103-adapter plate 1121203-adapter plate 12

21303-adapter plate 1321403-adapter plate 1421503-adapter plate 15

21603-adapter plate 1621703-adapter plate 1721803-adapter plate 18

21903 adapter plate 1922003 adapter plate 2022103 adapter plate 21

22203-adapter plate 2222303-adapter plate 2322403-adapter plate 24

20104-spherical hinge base 120204-spherical hinge base 220304-spherical hinge base 3

20404-ball joint base 420504-ball joint base 520604-ball joint base 6

20704-spherical hinge base 720804-spherical hinge base 820904-spherical hinge base 9

21004-ball pivot mount 1021104-ball pivot mount 1121204-ball pivot mount 12

21304 ball hinge base 1321404 ball hinge base 1421504 ball hinge base 15

21604-ball hinge base 1621704-ball hinge base 1721804-ball hinge base 18

21904-ball hinge base 1922004-ball hinge base 2022104-ball hinge base 21

22204-ball hinge base 2222304-ball hinge base 2322404-ball hinge base 24

20105-ball joint ball head 120205-ball joint ball head 220305-ball joint ball head 3

20405 ball joint ball head 420505 ball joint ball head 520605 ball joint ball head 6

20705-ball joint ball head 720805-ball joint ball head 820905-ball joint ball head 9

21005-ball joint ball head 1021105-ball joint ball head 1121205-ball joint ball head 12

21305 ball joint ball head 1321405 ball joint ball head 1421505 ball joint ball head 15

21605-ball joint ball head 1621705-ball joint ball head 1721805-ball joint ball head 18

21905-ball joint ball head 1922005-ball joint ball head 2022105-ball joint ball head 21

22205-ball joint ball head 2222305-ball joint ball head 2322405-ball joint ball head 24

20106-spherical hinge upper connecting piece 120206-spherical hinge upper connecting piece 220306-spherical hinge upper connecting piece 3

20406-ball pivot upper connecting piece 420506-ball pivot upper connecting piece 520606-ball pivot upper connecting piece 6

20706-ball pivot Upper attachment 720806-ball pivot Upper attachment 820906-ball pivot Upper attachment 9

21006 ball pivot upper connector 1021106 ball pivot upper connector 1121206 ball pivot upper connector 12

21306 ball pivot Upper connector 1321406 ball pivot Upper connector 1421506 ball pivot Upper connector 15

21606-ball hinge Upper connector 1621706-ball hinge Upper connector 1721806-ball hinge Upper connector 18

21906 ball pivot Upper connector 1922006 ball pivot Upper connector 2022106 ball pivot Upper connector 21

22206-ball pivot Upper connector 2222306-ball pivot Upper connector 2322406-ball pivot Upper connector 24

20107-middle U-shaped fork 120207-middle U-shaped fork 220307-middle U-shaped fork 3

20407 middle U-shaped fork 420507 middle U-shaped fork 520607 middle U-shaped fork 6

20707-middle U-fork 720807-middle U-fork 820907-middle U-fork 9

21007 middle U-shaped fork 1021107 middle U-shaped fork 1121207 middle U-shaped fork 12

21307 middle U-fork 1321407 middle U-fork 1421507 middle U-fork 15

21607-middle U-fork 1621707-middle U-fork 1721807-middle U-fork 18

21907 middle U-fork 1922007 middle U-fork 2022107 middle U-fork 21

22207-middle U-shaped fork 2222307-middle U-shaped fork 2322407-middle U-shaped fork 24

20108-Upper U-shaped fork 120208-Upper U-shaped fork 220308-Upper U-shaped fork 3

20408-Upper U-fork 420508-Upper U-fork 520608-Upper U-fork 6

20708-upper U-fork 720808-upper U-fork 820908-upper U-fork 9

21008-Upper U-fork 1021108-Upper U-fork 1121208-Upper U-fork 12

21308 Upper U-fork 1321408 Upper U-fork 1421508 Upper U-fork 15

21608-Upper clevis 1621708-Upper clevis 1721808-Upper clevis 18

21908 Upper clevis 1922008 Upper clevis 2022108 Upper clevis 21

22208-Upper U-fork 2222308-Upper U-fork 2322408-Upper U-fork 24

50101-upper platform 50201-upper hinge seat 150202-upper hinge seat 2

50203 upper hinge seat 350204, upper hinge seat 450205 and upper hinge seat 5

50206, upper hinge seat 650207, upper hinge seat 750208, and upper hinge seat 8

50209-upper hinge base 950210-upper hinge base 1050211-upper hinge base 11

50212 upper hinge seat 1250301 central sensor seat 50302 side sensor seat

50401 acceleration sensor 150402 acceleration sensor 250403 acceleration sensor 3

50404 acceleration sensor 450405 acceleration sensor 550406 acceleration sensor 6

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

As shown in figure 1, the invention is a six-degree-of-freedom vibration excitation system with a four-stage Stewart mechanism parallel configuration, the six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is a novel six-degree-of-freedom parallel mechanism configuration, the mechanism configuration of the system is a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, twenty-four actuator branch circuits of the system are divided into four groups, the layout mode of each group in space is a Stewart configuration, and the four groups of Stewart configurations form the six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism in a parallel mode instead of the six-degree-of-freedom;

the device is distributed according to a four-stage Stewart mechanism six-degree-of-freedom configuration and comprises an actuator branch, an air spring branch, an auxiliary support branch, an upper platform assembly, a lower platform assembly and a real-time control hardware system; the actuator branch circuits are divided into twenty-four branches and are used for providing accurate and controllable output force for the system; the air spring branches are divided into sixteen branches in a typical design, are used for providing supporting force for counteracting gravity for a moving part of the system during working, and are respectively connected with the upper platform assembly and the lower platform assembly through outer hexagon screws; the auxiliary supporting branches are divided into twelve branches in a typical design, and are used for providing supporting force for counteracting gravity for the system moving part at the end of the test and during automatic inflation, and the supporting force provided during automatic inflation is used as a feedback signal to be input into the automatic inflation control system; the upper platform assembly is used for providing a rigid mechanical mounting table for the test piece and observing the simulated vibration signal through the measured acceleration signal; the lower platform assembly is used for providing a stable installation foundation for the system; the real-time control hardware system calculates a control signal under a four-stage Stewart mechanism six-degree-of-freedom parallel configuration through the acquired six-degree-of-freedom acceleration signal of the upper platform, and outputs the control signal to the power amplifier so as to drive the actuator to output axial telescopic motion and push the upper platform to generate an expected vibration excitation signal.

The four-stage Stewart mechanism six-degree-of-freedom parallel configuration diagram is shown in figure 2, four classical single-stage Stewart configurations are combined in parallel on the same horizontal plane, the centers of upper table tops of the four Stewart configuration mechanisms can form a quadrangle, the center of the upper table top of the whole Stewart mechanism is positioned in the quadrangle, a typical layout mode is that the centers of the upper table tops of the four Stewart configuration mechanisms are rotationally symmetrical around a Z axis of the center of the whole Stewart mechanism, namely the centers of the upper table tops of the four Stewart classical configurations and the direction of a ray connected with the center of the upper table top of the whole Stewart mechanism form an included angle of 90 degrees, and the centers of the upper table tops of the four Stewart classical configurations are completely superposed after rotating for 90 degrees around the Z axis of the center of the whole Stewart mechanism; the centers of the upper table tops of the four Stewart classical configurations are on a circle which takes the center of the whole upper table top as the center of a circle and takes a certain distance as the radius.

The arrangement directions of the four classical single-stage Stewart configurations are four implementation modes, and configuration top views of the implementation modes 1-4 are shown in figures 3-6:

the top view of the configuration of the implementation mode 1 is shown in fig. 3, the forward direction of the X axis of each classical single-stage Stewart configuration points to the opposite direction of the connecting line of the center of the upper table top of each classical single-stage Stewart configuration and the center of the upper table top of the whole table, namely, the outward rotational symmetry implementation mode of the forward direction of the X axis of each single stage;

implementation mode 2 the plan view of the configuration is shown in fig. 4, the positive direction of the X axis of each classical single-stage Stewart configuration points to the direction of the connecting line of the center of the upper table top of each classical single-stage Stewart configuration and the center of the upper table top of the whole table, i.e. the inward rotational symmetry implementation mode of the positive direction of the X axis of each single stage;

implementation mode 3 the top view of the configuration is shown in fig. 5, and four classical single-stage Stewart configurations have the same positive direction of the X axis, namely, the single-stage Stewart configuration has the same rotational symmetry implementation mode of the X axis direction;

implementation mode 4 configuration top view is shown in fig. 6, the positive directions of the X axes of the two classical single-stage Stewart configurations on one side are opposite to the positive directions of the X axes of the two classical single-stage Stewart configurations on the other side, and the two classical single-stage Stewart configurations are symmetrical about a certain axis, namely, the two single-stage Stewart configurations on the two sides are axisymmetric in the opposite directions of the X axes.

In each implementation mode, the configuration layouts of the air spring branches and the auxiliary support branches are arranged according to the direction of a single-stage classical Stewart configuration, the top view is only schematic, and the specific number and the installation position of the air spring branches and the auxiliary support branches can be adjusted according to different loads of the whole platform.

The mechanical structure of the vibration simulation system is shown in fig. 7 and 8, and comprises 10000 lower platform assembly, 20100

actuator branch

1, 20200

actuator branch

2, 20300

actuator branch

3, 20400

actuator branch

4, 20500 actuator branch 5, 20600 actuator branch 6, 20700 actuator branch 7, 20800 actuator branch 8, 20900 actuator branch 9, 21000 actuator branch 10, 21100 actuator branch 11, 212000 actuator branch 12, 21300 actuator branch 13, 21400

actuator branch

14, 21500 actuator branch 15, 21600 actuator branch 16, 21700 actuator branch 17, 21800 actuator branch 18, 21900 actuator branch 19, 22000 actuator branch 20, 22100 actuator branch 21, 22200 actuator branch 22, 22300 actuator branch 23, 22400 actuator branch 24, 30100

air spring branch

1, 30200

air spring branch

2, 30300

air spring branch

3, 30400

air spring branch

4, and, 30500, 30600, 30700, 30800, 30900, 31000, 31100, 31200, 31300, 31400, 31500, 31600, 16, 40100, 1, 40200, 40300, 40400, 40500, 40600, 40700, 40800, 8, 40900, 41000, 10, 41100, 11, 41200 and 50000 upper platform assembly.

10000 lower platform components are shown in fig. 9, the lower platform is a casting platform, and mounting holes are distributed on the lower platform and are respectively connected with the foundation, each actuator branch, each air spring branch and each auxiliary support branch.

The twenty-four

actuator branches

20100, 20200, 20300, 20400, 20500, 20600, 20700, 20800, 20900, 21000, 21100, 212000, 21300, 21400, 21500, 21600, 21700, 21800, 21900, 22000, 22100, 22200, 22300 and 22400 are structurally the same, and take an actuator branch 1 as an example, as shown in fig. 10, the actuator branch comprises an actuator 20101, a lower connecting block of 20102, an adapter plate of 20103, a spherical hinge base of 20104, a spherical hinge ball head of 20105, an upper connecting piece of a 20106 spherical hinge, a U-shaped fork in 20107 and a U-shaped fork on 20108.

Each part forms twenty-four actuator branch circuits in the following connection mode:

the lower 20102 connecting block in the 20100 actuator branch 1 is arranged at the bottom of the 20101 actuator through eight hexagon socket head bolts and is positioned with a positioning hole at the bottom of the 20101 actuator through a positioning pin; the 20104 spherical hinge base and the 20105 spherical hinge ball head are installed in a matched mode through eight outer hexagonal bolts, the 20106 spherical hinge upper connecting piece and the 20105 spherical hinge ball head are installed coaxially through threads, the U-shaped fork in the 20107 and the 20106 spherical hinge upper connecting piece are installed in parallel through the eight outer hexagonal bolts, the U-shaped fork in the 20108 and the U-shaped fork in the 20107 are installed in a mutually perpendicular mode through a cross shaft, two pairs of rolling bearings and thirty-two outer hexagonal bolts, and therefore the hinge assembly 1 is formed; the 20104 spherical hinge base in the hinge assembly 1 is connected with the 20101 actuator moving coil through the 20103 adapter plate, and the connection line of the rotation centers is ensured to be matched with the axis of the moving coil through the positioning hole.

The

actuator branches

20200, 20300, 20400, 20500, 20600, 20700, 20800, 20900, 21000, 21100, 212000, 21300, 21400, 21500, 21600, 21700, 21800, 21900, 22000, 22100, 22200, 22300 and 22400 are the same as the actuator branches 20100, and the specific embodiments are the same.

The sixteen

air spring branches

30100, 30200, 30300, 30400, 30500, 30600, 30700, 30800, 30900, 31000, 31100, 31200, 31300, 31400, 31500, and 31600 have the same structure, wherein four air spring branches corresponding to the same single-stage Stewart classic configuration are divided into one group, and each group of air spring branches is formed by air spring branches in the four-stage Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1 according to a specific implementation mode of a four-stage Stewart mechanism six-degree-of-freedom parallel configuration, as shown in fig. 11.

All the air spring branches are formed by the following arrangement modes:

30100. 30200, 30300, 30400 the air spring branches are distributed on the same horizontal plane and are in a quadrilateral layout, and the center of the upper table top of the single-stage Stewart classical configuration is generally in the quadrilateral.

The

air spring branches

30500, 30600, 30700 and 30800 form a group, the

air spring branches

30900, 31000, 31100 and 31200 form a group, and the

air spring branches

31300, 31400 and 31600 form a group which has the same structure as the

air spring branches

30100, 30200, 30300 and 30400, and the specific implementation mode is the same.

The four groups of air spring branches formed above form all air spring branches on the same horizontal plane in a rotational symmetry mode according to a four-level Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1.

The twelve

auxiliary support branches

40100, 40200, 40300, 40400, 40500, 40600, 40700, 40800, 40900, 41000, 41100 and 41200 have the same structure, wherein three auxiliary support branches corresponding to the same single-stage Stewart classical configuration are divided into one group, and each group of auxiliary support branches is composed of auxiliary support branches in a four-stage Stewart mechanism six-degree-of-freedom parallel configuration specific implementation mode, as shown in fig. 12, in a four-stage Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1.

Each group of auxiliary support branches form all auxiliary support branches in the following arrangement mode:

40100. 40200 and 40300 auxiliary supporting branches are distributed on the same horizontal plane and are in a triangular layout, and the center of the upper table top of the single-stage Stewart classical configuration is generally in the triangle.

The

auxiliary support branches

40400, 40500 and 40600 are in one group, the

auxiliary support branches

40700, 40800 and 40900 are in one group, and the

auxiliary support branches

41000, 41100 and 41200 are in the same structure as the

auxiliary support branches

40100, 40200 and 40300, and the specific embodiments are the same.

The four groups of auxiliary supporting branches formed above form all auxiliary supporting branches on the same horizontal plane in a rotational symmetry mode according to a four-level Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1.

The 50000 upper platform assembly is shown in fig. 13, and comprises 50101 upper platform, 50201 upper hinge seat 1, 50202 upper hinge seat 2, 50203 upper hinge seat 3, 50204 upper hinge seat 4, 50205 upper hinge seat 5, 50206 upper hinge seat 6, 50207 upper hinge seat 7, 50208 upper hinge seat 8, 50209 upper hinge seat 9, 50210 upper hinge seat 10, 50211 upper hinge seat 11, 50212 upper hinge seat 12, 50301 center sensor seat, 50302 side sensor seat, 50401 acceleration sensor 1, 50402 acceleration sensor 2, 50403 acceleration sensor 3, 50404 acceleration sensor 4, 50405 acceleration sensor 5 and 50406 acceleration sensor 6; 50101 the lower surface of the upper platform has twelve locating slots, which are connected with the upper hinge seats respectively; 50301 central sensor seat is arranged at the center of the lower surface of an upper platform 50101 and is respectively connected with a 50401 sensor 1, a 50402 sensor 2 and a 50403 sensor 3 through three mounting holes for measuring the translational acceleration of the upper platform along X, Y and Z axes; the 50404 sensor 4 is connected to the intersection point of the Y axis and the reinforcing rib on the lower surface of the upper platform through a stud and is used for measuring the rotational acceleration of the upper platform around the X axis; 50302 the side sensor seat is arranged at the intersection point of the X axis and the reinforcing rib on the lower surface of the upper platform and is connected with a 50405 sensor 5 and a 50406 sensor 6 through two mounting holes for measuring the rotation acceleration of the upper platform around an Y, Z axis.

The twenty-four actuator branches are arranged in a position, taking a four-stage Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1 as an example, and are spatially arranged according to the four-stage Stewart mechanism parallel configuration of claim 1, as shown in fig. 2 and 3, and are sequentially connected with a 10000 lower platform component and a 50000 upper platform component, and the configuration of the four-stage Stewart mechanism parallel configuration is ensured by a mounting hole on the 10000 lower platform and a positioning groove (an upper hinge seat) on the 50101 upper platform, so that a mechanical motion part of a six-degree-of-freedom vibration simulation system with a specific function is formed:

the 20101 actuator in the 20100 actuator branch 1 is connected with a mounting hole in an 10000 lower platform through a 20102 lower connecting block, and a U-shaped fork on 20108 is in positioning connection with a 50201 upper hinge seat of a 50000 upper platform assembly through a positioning pin.

The 20201 actuator in the 20200 actuator branch 2 is connected with the mounting hole on the 10000 lower platform through the 20202 lower connecting block, and the 20208 upper U-shaped fork is connected with the 50202 upper hinge seat of the 50000 upper platform assembly through the locating pin.

The 20301 actuator in the 20300 actuator branch 3 is connected with the mounting hole on the 10000 lower platform through the 20302 lower connecting block, and the 20308 upper U-shaped fork is connected with the 50202 upper hinge seat of the 50000 upper platform component through the locating pin.

The 20401 actuator in the 20400 actuator branch 4 is connected with a mounting hole on an 10000 lower platform through a 20402 lower connecting block, and a 20408 upper U-shaped fork is connected with a 50203 upper hinge seat of a 50000 upper platform assembly in a positioning mode through a positioning pin.

The 20501 actuator in the 20500 actuator branch 5 is connected with a mounting hole on an 10000 lower platform through an 20502 lower connecting block, and a 20508 upper U-shaped fork is connected with a 50203 upper hinge seat of a 50000 upper platform assembly in a positioning mode through a positioning pin.

The 20601 actuator in the 20600 actuator branch 6 is connected with a mounting hole on the 10000 lower platform through a 20602 lower connecting block, and the 20608 upper U-shaped fork is connected with a 50201 upper hinge seat of the 50000 upper platform assembly in a positioning mode through a positioning pin.

And a 20701 actuator in the 20700 actuator branch circuit 7 is connected with a mounting hole on the 10000 lower platform through a 20702 lower connecting block, and a U-shaped fork on 20708 is connected with a hinge seat on 50204 of the 50000 upper platform assembly in a positioning manner through a positioning pin.

The 20801 actuator in 20800 actuator branch 8 is connected with the mounting hole on 10000 lower platforms through 20802 lower connecting block, and 20808 upper U-shaped fork is connected with 50205 upper hinge base of 50000 upper platform assembly through positioning pin.

The 20901 actuator in the 20900 actuator branch 9 is connected with the mounting hole on the 10000 lower platform through the 20902 lower connecting block, and the 20908 upper U-shaped fork is connected with the 50205 upper hinge seat of the 50000 upper platform assembly in a positioning way through a positioning pin.

The 21001 actuator in the 21000 actuator branch 10 is connected with a mounting hole on an 10000 lower platform through a 21002 lower connecting block, and a 21008 upper U-shaped fork is connected with a 50206 upper hinge seat of a 50000 upper platform assembly in a positioning mode through a positioning pin.

21101 actuators in a 21100 actuator branch circuit 11 are connected with mounting holes on 10000 lower platforms through 21102 lower connecting blocks, and 21108 upper U-shaped forks are connected with 50206 upper hinge seats of 50000 upper platform assemblies in a positioning mode through positioning pins.

The 21200 actuator branch 12 has its 21201 actuator connected via a connecting block at 21202 to the mounting hole on the 10000 lower platform, and the 21208 upper U-shaped fork is connected via a locating pin to the 50204 upper hinge seat of the 50000 upper platform assembly.

21301 actuators in the actuator branch 13 are connected with mounting holes on 10000 lower platforms through 21302 lower connecting blocks, 21308 upper U-shaped forks are connected with 50207 upper hinge seats of 50000 upper platform assemblies through positioning pins in a positioning mode.

21401 actuator in 21400 actuator branch 14 is connected with mounting hole on 10000 lower platform through 21402 lower connecting block, 21408 upper U-shaped fork is connected with 50208 upper hinge base of 50000 upper platform component through locating pin.

The 21501 actuator in the 21500 actuator branch 15 is connected with the mounting hole on the 10000 lower platform through the 21502 lower connecting block, and the 21508 upper U-shaped fork is connected with the 50208 upper hinge seat of the 50000 upper platform assembly in a positioning mode through the positioning pin.

The 21601 actuator in the 21600 actuator branch 16 is connected with the mounting hole on the 10000 lower platform by the 21602 lower connecting block, and the 21608 upper U-shaped fork is connected with the 50209 upper hinge seat of the 50000 upper platform assembly by a positioning pin.

The 21701 actuator in the 21700 actuator branch 17 is connected with the mounting hole on the 10000 lower platform through the 21702 lower connecting block, and the 21708 upper U-shaped fork is connected with the 50209 upper hinge seat of the 50000 upper platform assembly through the locating pin.

The 21801 actuator in the 21800 actuator branch 18 is connected with the mounting hole on 10000 lower platform by 21802 lower connecting block, and the 21808 upper U-shaped fork is connected with the hinge seat on 50207 of 50000 upper platform assembly by locating pin.

21901 actuators in the 21900 actuator branch 19 are connected with mounting holes on 10000 lower platforms through 21902 lower connecting blocks, and 21908 upper U-shaped forks are connected with 50000 upper platform assembly hinge seats on 50210 through positioning pins.

The 22001 actuator in the 22000 actuator branch 20 is connected with a mounting hole on an 10000 lower platform through a 22002 lower connecting block, and the 22008 upper U-shaped fork is connected with a 50211 upper hinge seat of a 50000 upper platform assembly in a positioning mode through a positioning pin.

22101 actuator in 22100 actuator branch 21 is connected with mounting hole on 10000 lower platform through 22102 lower connecting block, 22108 upper U-shaped fork is connected with 50211 upper hinge seat of 50000 upper platform assembly through locating pin.

The 22201 actuator in the 22200 actuator branch 22 is connected with the mounting hole on the 10000 lower platform through a 22202 lower connecting block, and the 22208 upper U-shaped fork is connected with the hinge seat on the 50212 of the 50000 upper platform assembly in a positioning mode through a positioning pin.

The 22301 actuator in the 22300 actuator branch 23 is connected with the mounting hole on the 10000 lower platform through a 22302 lower connecting block, and the 22308 upper U-shaped fork is connected with the 50212 upper hinge seat of the 50000 upper platform assembly through a positioning pin.

22401 actuators in 22400 actuator branch circuits 24 are connected with mounting holes in 10000 lower platforms through 22402 lower connecting blocks, and U-shaped forks on 22408 are connected with hinge seats on 50210 of 50000 upper platform assemblies in a locating mode through locating pins.

The position arrangement of sixteen air spring branches is implemented by taking a four-stage Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1 as an example, and according to claim 1, as shown in fig. 2, 3 and 11, the six air spring branches are sequentially connected with a 10000 lower platform assembly and a 50000 upper platform assembly to form an air spring part of a six-degree-of-freedom vibration simulation system with a specific function:

30100 the air spring branch 1 is connected with the mounting hole on 10000 lower platforms, and is connected with 50101 upper platform of 50000 upper platform assembly through bolt.

Air spring branches

30200, 30300, 30400, 30500, 30600, 30700, 30800, 30900, 31000, 31100, 31200, 31300, 31400, 31500, 31600 are structurally identical to air spring branch 30100 and are connected in the same manner as 10000 lower platform assembly and 50000 upper platform assembly.

The position arrangement of twelve auxiliary supporting branches takes a four-stage Stewart mechanism six-degree-of-freedom parallel configuration implementation mode 1 as an example, and according to claim 1, as shown in fig. 2, 3 and 12, the auxiliary supporting branches are sequentially connected with a 10000 lower platform component and a 50000 upper platform component to form an auxiliary supporting part of a six-degree-of-freedom vibration simulation system with a specific function:

40100 auxiliary stay branch road 1 links to each other with the mounting hole on the 10000 lower platform, is connected with the 50101 upper mounting plate location of 50000 upper mounting plate subassembly through the locating pin.

The

auxiliary support branches

40200, 40300, 40400, 40500, 40600, 40700, 40800, 40900, 41000, 41100, 41200 are structurally identical to the auxiliary support branch 40100 and are connected in the same manner as the 10000 lower platform component and the 50000 upper platform component.

The control loop of the real-time control hardware system is shown in fig. 14 and comprises a high-speed control computer, a multi-channel A/D data acquisition card, a multi-channel D/A data output card, a power amplifier, an acceleration sensor, a force sensor, a displacement sensor, a signal conditioner, a sensor tool and the like; the acceleration sensor is used for measuring six-degree-of-freedom acceleration of the upper platform, the six-degree-of-freedom acceleration is used as a feedback signal through the signal conditioner and the multi-channel A/D data acquisition card, a control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is generated through resolving by the high-speed control computer, a driving signal is generated through the multi-channel D/A data output card and the power amplifier, and then the actuator is controlled to output axial motion, so that the upper platform assembly is pushed to generate an expected simulated vibration signal; the force sensor is used for measuring the supporting force of the auxiliary supporting system on the upper table top, the supporting force is used as a feedback signal through the multichannel A/D data acquisition card, a control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is generated through resolving through the high-speed control computer, and an air charging and discharging control signal is generated through the multichannel D/A data output card to control the air charging and discharging process of each air spring branch; the displacement sensor is used for measuring the position of each actuator branch motor, the position is used as a feedback signal through the signal conditioner and the multi-channel A/D data acquisition card, a high-speed control computer is used for resolving to generate a displacement closed-loop control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, the displacement closed-loop control signal is generated through the multi-channel D/A data output card and the power amplifier, and then the position of each actuator is controlled to be stable near the central position, so that the safety and the stability of the upper platform assembly are kept.

When the four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system operates, a test piece is installed above a 50000 upper platform assembly, and then an auxiliary support and an air spring are adjusted to level a 50101 upper platform and unload gravity; the high-speed control computer is started, a desired time-frequency domain vibration control instruction can be input on a user interaction interface, a corresponding six-degree-of-freedom vibration excitation signal (comprising sine frequency sweep, random or user-induced time domain vibration signal and the like) is generated, and multi-degree-of-freedom vibration excitation in complex environments such as satellite-borne, missile-borne, airborne, carrier-borne or vehicle-borne is provided for a test piece (high-precision load, precision instrument and the like).

The six-degree-of-freedom vibration excitation system with the four-stage Stewart mechanism parallel configuration has the six-degree-of-freedom vibration simulation capability, the linear moving magnet type motor is used as an active element of the actuator branch circuit, and the spatial position of the actuator branch circuit is arranged through the specially designed six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, so that the six-degree-of-freedom vibration excitation system has the advantages of large working space, strong bearing capacity, large output force, high response speed and high control bandwidth.

The present invention is not disclosed in detail as belonging to the common general knowledge of the skilled person.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can understand that any replacement or addition or subtraction within the technical scope of the present invention should be included in the scope of the present invention. Those skilled in the art will appreciate that the alternatives and additions include, but are not limited to, the following exemplary embodiments within the scope of the present disclosure: the four-stage Stewart mechanism comprises specific configuration parameter values of six-degree-of-freedom parallel configuration (size parameters of single-stage and four-stage Stewart mechanism parallel configuration and the like), layout positions (which can not be rotationally symmetrical about the center of the whole platform) and directions of four single-stage Stewart sub-platforms, specific forms and types of linear actuators, hinge forms of precise hinge components for realizing five-degree-of-freedom rotation, the number and installation positions of air spring branches and auxiliary support branches and the like. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A six-degree-of-freedom vibration excitation system with a four-stage Stewart mechanism parallel configuration adopts a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, and comprises twenty-four actuator branches, a plurality of air spring branches, a plurality of auxiliary support branches, an upper platform assembly, a lower platform assembly and a real-time control hardware system; the method is characterized in that:

the twenty-four actuator branches are divided into four groups, and each group of six actuators forms a classic Stewart configuration mechanism; the upper table top of each Stewart classical configuration is a horizontal plane; the four Stewart configuration mechanisms are positioned on the same horizontal plane height, the centers of the upper table tops of the four Stewart configuration mechanisms form a quadrangle, the center of the upper table top of the whole Stewart configuration mechanism is positioned in the quadrangle, the layout mode is that the centers of the upper table tops of the four Stewart configuration mechanisms are rotationally symmetrical around the Z axis of the center of the whole Stewart configuration mechanism, namely the centers of the upper table tops of the four Stewart classic configurations and the center of the upper table top of the whole Stewart configuration mutually form an included angle of 90 degrees in the direction of the connecting line, and the centers of the upper table tops of the four Stewart classic configurations are completely overlapped; the centers of the upper table tops of the four Stewart classical configurations are on a circle which takes the center of the whole upper table top as the center of a circle and takes a certain distance as the radius; the four Stewart classical configurations belong to a four-stage parallel relation with respect to the configuration of the whole system, and are called four-stage Stewart mechanism six-degree-of-freedom parallel configurations;

the real-time control hardware system comprises a high-speed control computer, a multi-channel A/D data acquisition card, a multi-channel D/A data output card, a power amplifier, an acceleration sensor, a force sensor, a displacement sensor, a signal conditioner and a sensor tool; the system comprises an acceleration sensor, a multi-channel A/D data acquisition card, a multi-channel D/A data output card, a sensor and a matched signal conditioner, wherein the acceleration sensor is arranged on an upper platform assembly through a sensor tool, the force sensor is arranged on an auxiliary support system branch through a connecting piece, a displacement sensor is arranged on an actuator branch through the sensor tool, the multi-channel A/D data acquisition card and the multi-channel D/A data output card are arranged in a high-speed control computer case, the A/D acquisition card is connected with the sensor and the matched signal conditioner through a shielding wire and a junction box, the D/A data output card is connected with a power amplifier through a BNC shielding wire, and the power amplifier is matched with the actuators one by one to form a control loop of a real-time hardware control system; the acceleration sensor is used for measuring six-degree-of-freedom acceleration of the upper platform, the six-degree-of-freedom acceleration is used as a feedback signal through the signal conditioner and the multi-channel A/D data acquisition card, a control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is generated through resolving by the high-speed control computer, a driving signal is generated through the multi-channel D/A data output card and the power amplifier, and then the actuator is controlled to output axial motion, so that the upper platform assembly is pushed to generate an expected simulated vibration signal; the force sensor is used for measuring the supporting force of the auxiliary supporting system on the upper table top, the supporting force is used as a feedback signal through the multichannel A/D data acquisition card, a control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism is generated through resolving through the high-speed control computer, and an air charging and discharging control signal is generated through the multichannel D/A data output card to control the air charging and discharging process of each air spring branch; the displacement sensor is used for measuring the position of each actuator branch motor, the position is used as a feedback signal through the signal conditioner and the multi-channel A/D data acquisition card, a high-speed control computer is used for resolving to generate a displacement closed-loop control signal under a six-degree-of-freedom parallel configuration of the four-stage Stewart mechanism, the displacement closed-loop control signal is generated through the multi-channel D/A data output card and the power amplifier, and then the position of each actuator is controlled to be stabilized near the central position, so that the safety and the stability of the upper platform assembly are kept;

the configuration is a six-degree-of-freedom parallel configuration of a four-stage Stewart mechanism, and comprises four classical single-stage Stewart configurations which are connected in parallel; the classic single-stage Stewart structure comprises an upper table top, a lower table top, 6 actuator branches and an air spring branch or an auxiliary support branch, wherein each actuator branch is connected with the upper table top through an upper hinge point, each actuator branch is connected with the lower table top through a lower hinge point, and six upper hinge points and six lower hinge points are respectively distributed on an envelope circle of the upper table top and an envelope circle of the lower table top; every two adjacent upper hinge points are divided into one group, three groups in total, the included angle formed by each group of upper hinge points and the center of the upper table top is the same, every two adjacent lower hinge points can be divided into one group, three groups in total, and the included angle formed by each group of lower hinge points and the center of the lower table top is the same; in the classic single-stage Stewart configuration, the direction of the center of the upper table top pointing to the midpoint of a group of upper hinge points is the positive direction of an X axis, the direction of the center of the lower table top pointing to the center of the upper table top is the positive direction of a Z axis, and a right-hand coordinate system is met;

the implementation mode 4 is an axial symmetry implementation mode that the positive directions of the X axes of the two classical single-stage Stewart configurations on one side are opposite to the positive directions of the X axes of the two classical single-stage Stewart configurations on the other side and are symmetrical about a certain axis, namely the directions of the X axes of the single stages on the two sides are opposite;

the actuator branch circuits are divided into twenty-four branches, the functions of the actuator branch circuits are to provide accurate and controllable output force for a system, and each branch circuit comprises an actuator, a hinge assembly, an adapter plate and a lower connecting block; the hinge assembly comprises a spherical hinge base, a spherical hinge ball head, a spherical hinge upper connecting piece, a middle U-shaped fork and an upper U-shaped fork; each part forms twenty-four actuator branch circuits in the following connection mode:

2. The four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system as claimed in claim 1, wherein:

the air spring branches are divided into sixteen air spring branches, or the number of the air spring branches is increased or decreased according to the capacity of the selected air spring model and the actual load weight of the whole air spring, the air spring branches are used for providing supporting force for counteracting gravity for a system moving part in work, the four air spring branches are arranged in a quadrilateral mode and are in one group, and each group of air spring branches can support a single-stage Stewart classical configuration;

3. The four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system as claimed in claim 1, wherein:

the auxiliary supporting branches are divided into twelve branches in a typical design, or the number of the auxiliary supporting branches is increased or decreased according to the capacity of a selected auxiliary supporting part and the actual load weight of the whole support, the auxiliary supporting branches are used for providing supporting force for counteracting gravity for a system motion part at the end of a test and during automatic inflation, the supporting force provided during automatic inflation is used as a feedback signal to be input into an automatic inflation control system, the layout mode is that three auxiliary supporting branches are in a group and distributed in a triangular mode, and each group of auxiliary supporting branches can realize the support of a single-stage Stewart classical configuration;

4. The four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system as claimed in claim 1, wherein:

the upper platform assembly is used for providing a rigid mechanical mounting table for the test piece and observing the simulated vibration signal through the measured acceleration signal; the device comprises an upper platform, twelve upper hinge seats, a central sensor seat, a side sensor seat and six acceleration sensors; twelve positioning grooves are formed in the edge of the lower surface of the upper platform and are respectively connected with twelve upper hinge seats; the central sensor seat is arranged at the center of the lower surface of the upper platform, is respectively connected with the sensor 1, the sensor 2 and the sensor 3 through three mounting holes and is used for measuring the translational acceleration of the upper platform along X, Y and Z axes; the sensor 4 is connected to the intersection of the Y axis and the reinforcing rib on the lower surface of the upper platform through a stud and is used for measuring the rotation acceleration of the upper platform around the X axis; the side sensor seat is arranged at the intersection of the X axis of the lower surface of the upper platform and the reinforcing rib, is connected with the sensor 5 and the sensor 6 through two mounting holes and is used for measuring the rotation acceleration of the upper platform around the Y, Z axis.

5. The four-stage Stewart mechanism parallel configuration six-degree-of-freedom vibration excitation system as claimed in claim 1, wherein:

the lower platform assembly is used for providing a stable installation foundation for the system, is fixedly connected with the foundation through foundation screws, and transmits the vibration of the system to the vibration isolation foundation to protect peripheral equipment.