CN113479355B - Ground variable-centroid zero-gravity simulation device and method - Google Patents

Ground variable-centroid zero-gravity simulation device and method Download PDF

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CN113479355B
CN113479355B CN202110925024.8A CN202110925024A CN113479355B CN 113479355 B CN113479355 B CN 113479355B CN 202110925024 A CN202110925024 A CN 202110925024A CN 113479355 B CN113479355 B CN 113479355B
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connecting rod
coordinate system
axis
linear module
module
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CN113479355A (en
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姚蔚然
张欧阳
杜德嵩
刘健行
孙光辉
吴立刚
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Harbin Institute of Technology
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Harbin Institute of Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G7/00—Simulating cosmonautic conditions, e.g. for conditioning crews

Abstract

A ground variable-centroid zero-gravity simulation device and a simulation method solve the problem that the performance of a space device is influenced by the existing microgravity simulation device, and belong to the field of ground zero-gravity simulation of space. A spherical air-float bearing seat is arranged on a base; the spherical air bearing pedestal supports the spherical air bearing rotor, and an air film is formed between the middle platform and the spherical air bearing rotor to enable the middle platform to be air-floated; the middle platform, the lower platform, the Z-direction movement module, the linear module fixing platform, the XY-direction movement module and the upper platform are sequentially connected from bottom to top; the center of mass sensitive element and the mechanical arm connecting rod are arranged on the upper platform; the controller controls the XY-direction movement module, the Z-direction movement module and the spherical air bearing rotor to jet air according to the change of the center of mass detected by the center-of-mass sensing element, so that the center of mass of the integrated piece moves to the center of the spherical air bearing rotor, and the center of mass adjustment is realized.

Description

Ground variable-centroid zero-gravity simulation device and method
Technical Field
The invention relates to the field of ground zero-gravity simulation of space, in particular to a ground variable-centroid zero-gravity simulation device and a ground variable-centroid zero-gravity simulation method applied to a space variable-centroid device.
Background
With the continuous development of aerospace technology, the tasks that people can realize in space are more diversified, and operating equipment is also bigger, complicated, and scalable. When a large-scale variable space device such as a space station is connected with a space manipulator for control, the fact that the mass center of the whole space device changes when the manipulator moves needs to be considered, the change of the mass center means that the coordinate conversion relation among sub-bodies changes, and at the moment, if the previous coordinate conversion relation is used, the control deviation occurs, the space task can fail, and even the space device can be damaged.
Because the cost of directly carrying out the space experiment is too large, when the motion of the space device is researched, the current mainstream method is to select a zero-gravity simulation device to carry out the experiment on the ground.
When a simulation experiment of the space device is carried out on the zero-gravity simulation device, the deformation motion of the space device can cause the mass center of the whole space device to change, and the key of the microgravity simulation lies in that a force which is opposite to the gravity of the device in the large direction is applied to the mass center of the simulated space device, so that the gravity is offset, and a simulated microgravity environment is provided for the space device. At present, in a traditional method, two sets of slide rails and mass blocks which are orthogonally arranged are added on a space device, and the mass center of the space device can be adjusted through the movement of a slide block on the slide rails, but in such a way, the whole space device is additionally loaded, the performance of the space device can be possibly reduced, and meanwhile, the mass center of the space device body is changed by the method, so that the mass characteristic of the space device body can be influenced.
Disclosure of Invention
The invention provides a ground variable-centroid zero-gravity simulation device and a ground variable-centroid zero-gravity simulation method, aiming at the problem that the performance of a space device is influenced by the existing microgravity simulation device.
The invention relates to a ground variable-centroid zero-gravity simulation device and a simulation method, wherein the device comprises a base 1, a lower platform 2, a spherical air bearing pedestal 3, a spherical air bearing rotor 24, a middle platform 5, a Z-direction movement module, a linear module fixing platform 25, an XY-direction movement module, an upper platform 17, a centroid sensing element 18, a mechanical arm connecting rod and a controller;
the spherical air bearing pedestal 3 is fixed on the base 1, the spherical air bearing rotor 24 is arranged on the spherical air bearing pedestal 3, the middle platform 5 is positioned above the spherical air bearing rotor 24, and air floatation can be formed between the middle platform 5 and the spherical air bearing rotor 24;
the lower platform 2 is positioned below the middle platform 5, the lower platform 2 is fixedly connected with the middle platform 5 through a support rod 23, the Z-direction movement module is arranged on the lower platform 2, the linear module fixing platform 25 is arranged on the Z-direction movement module, and the Z-direction movement module is used for driving the linear module fixing platform 25 to move in the vertical direction;
the XY direction movement module is arranged on the linear module fixing platform 25, the upper platform 17 is arranged on the XY direction movement module, and the XY direction movement module is used for driving the upper platform 17 to move on a horizontal plane;
the centroid sensing element 18 and the mechanical arm connecting rod are arranged on the upper platform 17 and are an integral piece;
the signal output end of the centroid sensing element 18 is connected with the signal input end of the controller, and the X, Y direction motion control signal output end of the controller is connected with the X, Y direction motion control signal input end of the XY direction motion module;
the Z-direction motion control signal output end of the controller is connected with the Z-direction motion control signal input end of the Z-direction motion module; the air injection control signal output end of the controller is connected with the air injection control signal input end of the spherical air bearing rotor 24.
In the simulation process, the controller controls the XY-direction motion module, the Z-direction motion module and the spherical air bearing rotor 24 to inject air according to the change of the center of mass detected by the center-of-mass sensing element 18, so that the center of mass of the integrated piece moves to the center of the spherical air bearing rotor 24, and the center of mass adjustment is realized.
Preferably, the mechanical arm connecting rod comprises a first section connecting rod 19, a second section connecting rod 20, a third section connecting rod 30 and a fourth section connecting rod 29;
the mechanical arm connecting rod comprises a first section of connecting rod 19, a second section of connecting rod 20, a third section of connecting rod 30 and a fourth section of connecting rod 29;
the first section of connecting rod 19, the second section of connecting rod 20, the third section of connecting rod 30 and the fourth section of connecting rod 29 are sequentially connected in a rotating mode, and the first section of connecting rod 19 is fixed on the upper platform 17.
Preferably, the Z-direction movement module includes 4Z-direction electric cylinders 22;
the 4 electronic jars 22 of Z direction are fixed under on platform 2, and sharp module fixed platform 25 is located under between platform 2 and the sharp module fixed platform 25, and the motion end of the electronic jar 22 of 4Z directions is connected with sharp module fixed platform 25's bottom surface, and the electronic jar 22 concerted movement of 4Z directions realizes the motion of sharp module fixed platform 25 in vertical direction.
Preferably, the XY-direction movement module comprises two sets of X-direction linear modules and two sets of Y-direction linear modules;
the two sets of X-direction linear modules are placed on the linear module fixing platform 25 in parallel;
each set of X-direction linear module is provided with two X-direction linear module sliders, one set of X-direction linear module sliders on the same side of the two sets of X-direction linear modules is provided, each set of X-direction linear module sliders is fixed with one set of Y-direction linear module, and the four X-direction linear module sliders cooperatively drive the two sets of Y-direction linear modules to realize X-direction movement; every set of Y direction sharp module is equipped with two Y direction sharp module sliders, and upper mounting plate 17 is fixed on four Y direction sharp module sliders, and four Y direction sharp module sliders drive upper mounting plate 17 in coordination and realize the motion of Y direction.
Preferably, the simulation device further comprises two primary weights 21, wherein one primary weight 4 is suspended on each side of the lower platform 2, and the primary weights 4 are used for ensuring that the lower platform 2 is kept horizontal when the simulation is not started.
Preferably, two secondary weights 4 are also included; two secondary counterweights 4 are respectively hung on two sides of the linear module fixing platform 25, and the secondary counterweights 4 are used for ensuring that the linear module fixing platform 25 keeps horizontal when simulation is not started.
The invention also provides a simulation method of the ground variable-centroid zero-gravity simulation device, which comprises the following steps:
s1, determining the combined mass center m of the mass center sensitive element 18, the mechanical arm connecting rod and the upper platform 17cPosition in coordinate system 0
Figure BDA0003208853220000031
According to
Figure BDA0003208853220000032
The displacement of the upper platform 17 in the coordinate system {0} is calculated, and the movement of the Z-direction movement module and the XY-direction movement module is controlled according to the displacement, so as to integrate the mass center mcTo the center of the spherical air bearing rotor 24;
coordinate system {0} is coordinate system O0X0Y0Z0Plane X0O0Y0Is arranged on the lower surface of the base 1 and has an origin O0Is located at the center of the lower surface of the base 1 and has an axis X0Parallel to the X direction in the XY direction motion module, and the axis Z0The plumb is upward;
s2, ventilating the spherical air bearing pedestal 3, forming a layer of air film between the spherical air bearing pedestal 3 and the spherical air bearing rotor 24, lifting the spherical air bearing rotor 24 together with the upper platform 17, the centroid sensing element 18 and the mechanical arm connecting rod in the air and freely rotating around the spherical center of the spherical air bearing rotor 24, realizing microgravity simulation, and starting the mechanical arm connecting rod to work;
s3, acquiring the angle of the mechanical arm connecting rod at the moment when the current control cycle is ended:
Figure BDA0003208853220000033
and
Figure BDA0003208853220000034
according to
Figure BDA0003208853220000035
Figure BDA0003208853220000036
And
Figure BDA0003208853220000037
obtaining a current combined centroid mcPosition in coordinate system 0
Figure BDA0003208853220000038
According to
Figure BDA0003208853220000039
Calculating the displacement of the X-direction linear module, the Y-direction linear module and the Z-direction motion module in the current control period
Figure BDA00032088532200000310
And
Figure BDA00032088532200000311
and controlling the movement thereof, i ═ i +1, repeating S3;
Figure BDA00032088532200000312
and
Figure BDA00032088532200000313
respectively showing the included angles between the first section of connecting rod 19 and the second section of connecting rod 20, between the second section of connecting rod 20 and the third section of connecting rod 30, and between the third section of connecting rod 30 and the fourth section of connecting rod 29 in the ith control period; i is 1,2, … ….
Preferably, the combined center of mass m of the center of mass sensor 18, the mechanical arm connecting rod and the upper platform 17 is determined in S1cPosition in coordinate system 0
Figure BDA00032088532200000314
The method comprises the following steps:
s11, establishing a coordinate system O0X0Y0Z0Coordinate system O1X1Y1Z1Coordinate system O2X2Y2Z2Coordinate system O3X3Y3Z3And a coordinate system O4X4Y4Z4The center of mass of the upper platform 17, the center of mass sensor 18 and the first section of connecting rod 19 is recorded as m1The centroid of the second segment of the connecting rod 20 is marked as m2The centroid of the third link 30 is denoted as m3The centroid of the fourth segment of the connecting rod 29 is recorded as m4(ii) a Determining centroid m1Has homogeneous coordinates in the coordinate system {1} of
Figure BDA0003208853220000041
Center of massm2Has homogeneous coordinates in the system {2}, of
Figure BDA0003208853220000042
Centroid m3Has homogeneous coordinates in the system {3}, of
Figure BDA0003208853220000043
Centroid m4Has homogeneous coordinates in the system {4}, of
Figure BDA0003208853220000044
Coordinate system O0X0Y0Z0Mid-plane X0O0Y0Is arranged on the lower surface of the base 1 and has an origin O0Is located at the center of the lower surface of the base 1 and has an axis X0Parallel to the direction of movement of the X-axis linear module, axis Z0Plumb-bob up, coordinate system O0X0Y0Z0Abbreviated as coordinate system {0 };
coordinate system O1X1Y1Z1Origin O1Is located at the center of the upper platform 17, axis X1Parallel to the direction of movement of the X-axis linear module, axis Z1Plumb-bob up, coordinate system O1X1Y1Z1Abbreviated as coordinate system {1 };
coordinate system O2X2Y2Z2Is the intersection of the axis of rotation of the second link 20 relative to the first link 19 and the axis of rotation of the third link 30 relative to the second link 20, and axis Z2The rotation direction is defined as the axis Z in line with the rotation axis of the second link 20 relative to the first link 192Forward, coordinate system O2X2Y2Z2Abbreviated as coordinate system {2 };
coordinate system O3X3Y3Z3Is the intersection of the axis of the third link segment 30 and the axis of the second link segment 20, and the axis Z3The rotation axis of the third-stage link 30 relative to the second-stage link 20 is collinear, and the positive rotation direction is defined as the axis Z3Forward direction; of the third link 30Axis and axis X3Collinear, axis Z3And the axis Y2Co-directional and co-linear, coordinate system O3X3Y3Z3Abbreviated as coordinate system {3 };
coordinate system O4X4Y4Z4Is the intersection of the axis of the fourth link 29 and the axis of the third link 30, and the axis Z4The rotation axis of the fourth link 29 relative to the third link 30 is collinear, and the positive rotation direction is defined as the axis Z4Positive, axis Z4And axis X3Perpendicularly intersecting, axis Z4And axis Z3Parallel to the axis Z of the fourth link 294Collinear; coordinate system O4X4Y4Z4Abbreviated as coordinate system {4 };
s12, calculating the centroid m1Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000045
Comprises the following steps:
Figure BDA0003208853220000046
in the formula:
Figure BDA0003208853220000051
wherein:
Figure BDA0003208853220000052
Figure BDA0003208853220000053
α, β, γ are X of the coordinate system {1} relative to the coordinate system {0}1、Y1、Z1Rotation angle of three axes, [ x ]1,y1,z1]T
Is the position coordinate of the origin of the coordinate system {1} in the coordinate system {0 };
s13, calculating the centroid m2Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000054
Comprises the following steps:
Figure BDA0003208853220000055
in the formula:
Figure BDA0003208853220000056
wherein
Figure BDA0003208853220000057
Is the angle of rotation, [ x ] of the current second link 202,y2,z2]TIs the position coordinate of the origin of the coordinate system {2} in the coordinate system {1 };
s14, calculating the centroid m3Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000058
Comprises the following steps:
Figure BDA0003208853220000059
in the formula:
Figure BDA00032088532200000510
wherein, theta3Is the angle of rotation, b, of the present third link 301Represents a point O2And point O3The distance between them;
s15, calculating the centroid m4Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000061
Comprises the following steps:
Figure BDA0003208853220000062
in the formula:
Figure BDA0003208853220000063
wherein, theta4Is the angle of rotation of the present fourth link 29, b2Represents a point O3And point O4Along the axis Z4A distance of l1Represents a point O3And point O4Along the axis X3The distance of (d);
s16, calculating the centroid m1、m2、m3、m4Combined centroid mcPosition in coordinate System {0}
Figure BDA0003208853220000064
Figure BDA0003208853220000065
According to the centroid synthesis theorem, there are:
Figure BDA0003208853220000066
displacement of upper stage 17 under the coordinate system {0}
Figure BDA0003208853220000067
Comprises the following steps:
Figure BDA0003208853220000068
wherein h is the height of the center of the spherical air bearing rotor 24 relative to the lower surface of the lower stage 2, and the coordinate of the center of the spherical air bearing rotor 24 in the coordinate system {0} is [0,0, h ]]T。
Preferably, in S1, the controlling the movement of the Z-direction movement module and the XY-direction movement module based on the displacement amount includes:
s17, number of pulses N sent to X-direction linear module driving motor 6pul_xComprises the following steps:
Figure BDA0003208853220000069
ωmotor_xangle omega for representing rotation required by X-direction linear module driving motor 6motor_xThe number of pulses corresponding to one rotation of the X-direction linear module driving motor 6 is N1，[]Expressing taking an integer;
if omegamotor_xIf the number is positive, the motor rotates forwards; if negative, the motor is reversed, and the X-direction linear module driving motor 6 can drive the upper platform 17 on the X-axis0Direction movement
Figure BDA0003208853220000071
S18, number of pulses N sent to Y-direction linear module driving motor 16pul_yComprises the following steps:
Figure BDA0003208853220000072
in the formula (2)]The number of pulses corresponding to one rotation of the Y-direction linear module driving motor 16 is N2Angle omega of rotation required by the Y-direction linear module driving motor 16motor_y；
If omegamotor_yIf the number is positive, the motor rotates forwards; if negative, the motor is reversed and the motor drives the upper table 17 in the Y axis0Direction movement
Figure BDA0003208853220000073
S19, moving the module in Z direction according to the instruction to drive the upper platform 17 to move on the axis Z0Direction movement
Figure BDA0003208853220000074
Preferably, in S17, the first step,
Figure BDA0003208853220000075
wherein, the X-direction linear module adopts an X-direction driving motor transmission gear 11, an X-direction linear module transmission gear 10 and an X-direction linear module lead screw to realize the transmission of the X-direction linear module slide block,
Figure BDA0003208853220000076
the radius of the drive gear 11 of the X-direction drive motor is shown,
Figure BDA0003208853220000077
is the radius of the X-direction linear module transmission gear 10,
Figure BDA0003208853220000078
the lead of the lead screw of the X-direction linear module is shown;
Figure BDA0003208853220000079
the Y-direction linear module adopts a Y-direction linear module lead screw 14 to realize the transmission of a Y-direction linear module slide block,
Figure BDA00032088532200000710
the lead of the Y-direction linear module lead screw 14 is shown.
The invention has the beneficial effects that the invention provides a set of device capable of simultaneously completing the mass center adjusting task of the space mass center changing device during the ground zero gravity simulation experiment of the space mass center changing device and a corresponding leveling method. The ground zero-gravity simulation device capable of finishing the center-of-mass leveling mainly has the following advantages that:
(1) the ground zero-gravity simulation device provided by the invention can realize ground zero-gravity simulation test of the space metamorphic center device, for example, the device can be used for the ground zero-gravity simulation test of a space robot with a movable mechanism and a center-of-mass sensitive device, and the traditional simulation system can not adapt to the ground simulation experiment of the space metamorphic center device.
(2) Compared with the traditional mass center adjusting device, the mass center adjusting device can adjust the mass center of the outer space device to the spherical center of the air floating ball of the ground zero-gravity simulator without changing the structure and the mass characteristics of the outer space metamorphic center device.
(3) The simulation device can perform ground simulation experiments on any space metamorphic core device, does not need a traditional method for adjusting the mass center, needs to design how to place two sets of orthogonal sliding rails on the sliding block for each set of space metamorphic core device independently, and can use one set of device to complete the experiments on various space metamorphic core devices.
Drawings
FIG. 1 is a schematic structural diagram of a ground centroid-changing zero-gravity simulation device of a space centroid-changing device; the device comprises a base 1, a lower platform 2, a spherical air bearing pedestal 3, a secondary counterweight 4, a middle platform 5, an X-direction linear module driving motor 6, an X-direction driving motor fixing plate 7, an X-direction transmission belt 8, an X-direction linear module track 9, an X-direction linear module transmission gear 10, an X-direction driving motor transmission gear 11, a Y-direction fixing track 12, a Y-direction linear module track 13, a Y-direction linear module lead screw 14, a Y-direction linear module sliding block 15, a Y-direction linear module driving motor 16, an upper platform 17, a mass center sensitive element 18, a first section connecting rod 19, a second section connecting rod 20, a primary counterweight 21, a Z-direction electric cylinder 22, a supporting rod 23, a spherical air bearing rotor 24, a linear module fixing platform 25, a fourth section connecting rod 29 and a third section connecting rod 30, wherein the spherical air bearing rotor is arranged on the base 1;
fig. 2 is a coordinate system and related dimension definition diagram of the ground variable-centroid zero-gravity simulation device.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
The ground variable-centroid zero-gravity simulation device comprises a base 1, a lower platform 2, a spherical air bearing pedestal 3, a spherical air bearing rotor 24, a middle platform 5, a Z-direction movement module, a linear module fixing platform 25, an XY-direction movement module, an upper platform 17, a centroid sensing element 18, a mechanical arm connecting rod and a controller;
the spherical air bearing pedestal 3 is fixed on the base 1, the spherical air bearing rotor 24 is arranged on the spherical air bearing pedestal 3, the middle platform 5 is positioned above the spherical air bearing rotor 24, and air floatation can be formed between the middle platform 5 and the spherical air bearing rotor 24;
the lower platform 2 is positioned below the middle platform 5, the lower platform 2 is fixedly connected with the middle platform 5 through a support rod 23, the Z-direction movement module is arranged on the lower platform 2, the linear module fixing platform 25 is arranged on the Z-direction movement module, and the Z-direction movement module is used for driving the linear module fixing platform 25 to move in the vertical direction;
the XY direction movement module is arranged on the linear module fixing platform 25, the upper platform 17 is arranged on the XY direction movement module, and the XY direction movement module is used for driving the upper platform 17 to move on a horizontal plane;
the centroid sensing element 18 and the mechanical arm connecting rod are arranged on the upper platform 17 and are an integral piece;
the signal output end of the centroid sensing element 18 is connected with the signal input end of the controller, and the X, Y direction motion control signal output end of the controller is connected with the X, Y direction motion control signal input end of the XY direction motion module;
the Z-direction motion control signal output end of the controller is connected with the Z-direction motion control signal input end of the Z-direction motion module; the air injection control signal output end of the controller is connected with the air injection control signal input end of the spherical air bearing rotor 24.
In the simulation process, the controller controls the XY-direction motion module, the Z-direction motion module and the spherical air bearing rotor 24 to inject air according to the change of the center of mass detected by the center-of-mass sensing element 18, so that the center of mass of the integrated piece moves to the center of the spherical air bearing rotor 24, and the center of mass adjustment is realized.
The base 1 of the embodiment is placed on a horizontal plane, and the base 1 upwards supports a spherical air bearing pedestal 3; the spherical air bearing pedestal 3 supports a spherical air bearing rotor 24, and the spherical air bearing rotor 24 can form a layer of air film between the middle platform 5 and the spherical air bearing rotor 24 through air injection, so that the middle platform 5 is air-floated; the middle platform 5 is connected to the lower platform 2 through 4 support rods 23; meanwhile, the lower platform 2 upwards supports the Z-direction movement module; the Z-direction movement module is arranged perpendicular to the lower platform 2, the linear module fixing platform 25 is supported upwards, and the movement of the linear module fixing platform 25 in the vertical direction can be realized by controlling the movement of the Z-direction movement module;
the linear module fixing platform 25 supports the XY-direction movement modules, and the two sets of X-direction linear modules are placed on two sides of the linear module fixing platform 25 in parallel; the X-direction linear module consists of an X-direction linear module driving motor 6, an X-direction driving motor fixing plate 7, an X-direction transmission belt 8, an X-direction linear module track 9, an X-direction linear module transmission gear 10, an X-direction driving motor transmission gear 11, an X-direction linear module sliding block and an X-direction linear module lead screw, wherein one X-direction linear module driving motor 6 is connected with two X-direction driving motor transmission gears 11, the two X-direction driving motor transmission gears 11 are fixed by using the two X-direction driving motor fixing plates 7, the two X-direction driving motor transmission gears 11 are connected with the two X-direction linear module transmission gears 10 through the two X-direction transmission belts 8 in opposite directions, the two X-direction linear module transmission gears 10 are fixed to two sets of X-direction linear module tracks 9, the two X-direction linear module sliding blocks are connected to one X-direction linear module lead screw and are integrally placed on one set of X-direction linear module track 9 The module rails 9 form an X-direction linear module, and the other set of modules have the same principle. The X-direction linear module driving motor 6 is controlled to move to drive the transmission gears 11 of the 2X-direction driving motors to move, the X-direction transmission belts 8 are respectively transmitted to X-direction linear module lead screws on the two sets of linear modules, and the X-direction linear module slide blocks are driven to move through the movement of the X-direction linear module lead screws, so that the movement in the X direction is realized; on the two sets of X-direction linear modules, two X-direction linear module sliding blocks positioned on the left side of the two sets of X-direction linear module rails 9 support a Y-direction fixed rail 12, and two X-direction linear module sliding blocks positioned on the right side of the two sets of X-direction linear module rails 9 support a Y-direction fixed rail 12;
the XY direction movement module upwards supports an upper platform 17 and drives the upper platform 17 to realize X, Y direction movement; a mass center sensing element 18 is arranged on the upper platform 17, whether the mass center changes or not can be judged through measurement information, and a mechanical arm connecting rod is arranged at the same time; the mechanical arm connecting rod can move at any angle in space; the upper platform 17 and the mechanical arm connecting rod form a space mass center variable device. According to the change of the mass center, the direction adjustment X, Y, Z movement module drives the upper platform 17, the mechanical arm connecting rod and the mass center sensing element 18 to move, and the mass center is adjusted to the center of the spherical air bearing rotor 24.
The Z-direction movement module in this embodiment includes 4Z-direction electric cylinders 22;
the 4 electronic jars 22 of Z direction are fixed under on platform 2, and sharp module fixed platform 25 is located under between platform 2 and the sharp module fixed platform 25, and the motion end of the electronic jar 22 of 4Z directions is connected with sharp module fixed platform 25's bottom surface, and the electronic jar 22 concerted movement of 4Z directions realizes the motion of sharp module fixed platform 25 in vertical direction.
In the embodiment, the XY direction movement module comprises two sets of X direction linear modules and two sets of Y direction linear modules;
the two sets of X-direction linear modules are placed on the linear module fixing platform 25 in parallel;
each set of X-direction linear module is provided with two X-direction linear module sliders, one set of X-direction linear module sliders on the same side of the two sets of X-direction linear modules is provided, each set of X-direction linear module sliders is fixed with one set of Y-direction linear module, and the four X-direction linear module sliders cooperatively drive the two sets of Y-direction linear modules to realize X-direction movement; every set of Y direction sharp module is equipped with two Y direction sharp module sliders, and upper mounting plate 17 is fixed on four Y direction sharp module sliders, and four Y direction sharp module sliders drive upper mounting plate 17 in coordination and realize the motion of Y direction.
Specifically, as shown in fig. 1, the linear module fixing platform 25 supports two sets of linear modules capable of moving in the X direction, and the two sets of linear modules in the X direction are placed on two sides of the linear module fixing platform 25 in parallel; the X-direction linear module consists of an X-direction linear module driving motor 6, an X-direction driving motor fixing plate 7, an X-direction transmission belt 8, an X-direction linear module track 9, an X-direction linear module transmission gear 10, an X-direction driving motor transmission gear 11, an X-direction linear module sliding block and an X-direction linear module lead screw, wherein one X-direction linear module driving motor 6 is connected with two X-direction driving motor transmission gears 11, the two X-direction driving motor transmission gears 11 are fixed by using the two X-direction driving motor fixing plates 7, the two X-direction driving motor transmission gears 11 are connected with the two X-direction linear module transmission gears 10 through the two X-direction transmission belts 8 in opposite directions, the two X-direction linear module transmission gears 10 are fixed to two sets of X-direction linear module tracks 9, the two X-direction linear module sliding blocks are connected to one X-direction linear module lead screw and are integrally placed on one set of X-direction linear module track 9 The module rails 9 form an X-direction linear module, and the other set of modules have the same principle. The X-direction linear module driving motor 6 is controlled to move to drive the transmission gears 11 of the 2X-direction driving motors to move, the X-direction transmission belts 8 are respectively transmitted to X-direction linear module lead screws on the two sets of linear modules, and the X-direction linear module slide blocks are driven to move through the movement of the X-direction linear module lead screws, so that the movement in the X direction is realized; on the two sets of X-direction linear modules, two X-direction linear module sliding blocks positioned on the left side of the two sets of X-direction linear module rails 9 support a Y-direction fixed rail 12, and two X-direction linear module sliding blocks positioned on the right side of the two sets of X-direction linear module rails 9 support a Y-direction fixed rail 12; the left Y-direction fixed rail 12 supports a Y-direction linear module; the Y-direction linear module consists of a Y-direction linear module track 13, a Y-direction linear module lead screw 14, Y-direction linear module sliding blocks 15 and a Y-direction linear module driving motor 16, wherein the two Y-direction linear module sliding blocks 15 are also connected to one Y-direction linear module lead screw 14 in series and placed on the Y-direction linear module track 13, the Y-direction linear module driving motor 16 is connected to one end of the Y-direction linear module lead screw 14, the Y-direction linear module lead screw 14 is driven to move by controlling the Y-direction linear module driving motor 16, the two Y-direction linear module sliding blocks 15 are further driven to move, and therefore the Y-direction movement is achieved; the right Y-direction fixed track 12 supports a Y-direction linear guide set; the Y-direction linear guide set consists of Y-direction linear module slide blocks 15 and Y-direction linear module guide rods, wherein the two Y-direction linear module slide blocks 15 are connected to the Y-direction linear module guide rods in series, and the two Y-direction linear module slide blocks 15 can be driven by external force to slide on the Y-direction linear module guide rods; the 4Y-direction linear module sliding blocks 15 positioned on the left side and the right side in the Y direction jointly support an upper platform 17 upwards, and when the 2 left Y-direction linear module sliding blocks 15 move, the 2 right Y-direction linear module sliding blocks 15 are driven to move together, so that the movement in the Y direction is realized;
the simulation platform further comprises two primary balance weights 21, one primary balance weight 4 is hung on each of two sides of the lower platform 2, and the primary balance weights 4 are used for ensuring that the lower platform 2 keeps horizontal when the simulation is not started.
The embodiment also comprises two secondary counterweights 4; two secondary counterweights 4 are respectively hung on two sides of the linear module fixing platform 25, and the secondary counterweights 4 are used for ensuring that the linear module fixing platform 25 keeps horizontal when simulation is not started.
In a preferred embodiment, the mechanical arm link of the present embodiment includes a first-segment link 19, a second-segment link 20, a third-segment link 30, and a fourth-segment link 29;
the mechanical arm connecting rod comprises a first section of connecting rod 19, a second section of connecting rod 20, a third section of connecting rod 30 and a fourth section of connecting rod 29;
the first section of connecting rod 19, the second section of connecting rod 20, the third section of connecting rod 30 and the fourth section of connecting rod 29 are sequentially connected in a rotating mode, and the first section of connecting rod 19 is fixed on the upper platform 17.
Coordinate system description and related dimension definition formed by four sections of connecting rods:
coordinate system O0X0Y0Z0Mid-plane X0O0Y0Is arranged on the lower surface of the base 1 and has an origin O0Is located at the center of the lower surface of the base 1 and has an axis X0Parallel to the direction of movement of the X-axis linear module, axis Z0Plumb-bob up, coordinate system O0X0Y0Z0Abbreviated as coordinate system {0 };
coordinate system O1X1Y1Z1Origin O1Is located at the center of the upper platform 17, axis X1Parallel to the direction of movement of the X-axis linear module, axis Z1Plumb-bob up, coordinate system O1X1Y1Z1Abbreviated as coordinate system {1 };
coordinate system O2X2Y2Z2Is the intersection of the axis of rotation of the second link 20 relative to the first link 19 and the axis of rotation of the third link 30 relative to the second link 20, and axis Z2The rotation direction is defined as the axis Z in line with the rotation axis of the second link 20 relative to the first link 192Forward, coordinate system O2X2Y2Z2Abbreviated as coordinate system {2 };
coordinate system O3X3Y3Z3Is the intersection of the axis of the third section of the connecting rod 30 and the axis of the second section of the connecting rod 2, and the axis Z3The rotation axis of the third-stage link 30 relative to the second-stage link 20 is collinear, and the positive rotation direction is defined as the axis Z3Forward direction; axis of third link 30 and axis X3Collinear, axis Z3And the axis Y2Co-directional and co-linear, coordinate system O3X3Y3Z3Abbreviated as coordinate system {3 };
coordinate system O4X4Y4Z4Is the intersection of the axis of the fourth link 29 and the axis of the third link 30, and the axis Z4The rotation axis of the fourth link 29 relative to the third link 30 is collinear, and the positive rotation direction is defined as the axis Z4Positive, axis Z4And axis X3Perpendicularly intersecting, axis Z4And axis Z3Parallel to the axis Z of the fourth link 294Collinear; coordinate system O4X4Y4Z4Abbreviated as coordinate system {4 };
the center of mass of the upper platform 17, the center of mass sensing element 18 and the first section of connecting rod 19 is recorded as m1The centroid of the second segment of the connecting rod 20 is marked as m2The centroid of the third link 30 is denoted as m3The centroid of the fourth segment of the connecting rod 29 is recorded as m4；
The simulation method of the ground variable-centroid zero-gravity simulation device of the embodiment comprises the following steps:
step one, determining the combined mass center m of the mass center sensitive element 18, the mechanical arm connecting rod and the upper platform 17cPosition in coordinate system 0
Figure BDA0003208853220000121
According to
Figure BDA0003208853220000122
The displacement of the upper platform 17 in the coordinate system {0} is calculated, and the movement of the Z-direction movement module and the XY-direction movement module is controlled according to the displacement, so as to integrate the mass center mcTo the center of the spherical air bearing rotor 24;
coordinate system {0} is coordinate system O0X0Y0Z0Plane X0O0Y0Is arranged on the lower surface of the base 1 and has an origin O0Is located at the center of the lower surface of the base 1 and has an axis X0Parallel to the X direction in the XY direction motion module, and the axis Z0The plumb is upward;
ventilating the spherical air bearing pedestal 3, forming a layer of air film between the spherical air bearing pedestal 3 and the spherical air bearing rotor 24, lifting the spherical air bearing rotor 24 together with the upper platform 17, the centroid sensing element 18 and the mechanical arm connecting rod in the air and freely rotating around the spherical center of the spherical air bearing rotor 24, realizing microgravity simulation, and starting the mechanical arm connecting rod to work;
step three, acquiring the angle of the mechanical arm connecting rod at the moment when the current control cycle is finished:
Figure BDA0003208853220000131
and
Figure BDA0003208853220000132
according to
Figure BDA0003208853220000133
Figure BDA0003208853220000134
And
Figure BDA0003208853220000135
obtaining a current combined centroid mcPosition in coordinate system 0
Figure BDA0003208853220000136
According to
Figure BDA0003208853220000137
Calculating the displacement of the X-direction linear module, the Y-direction linear module and the Z-direction motion module in the current control period
Figure BDA0003208853220000138
And
Figure BDA0003208853220000139
and controlling the movement thereof, i ═ i +1, repeating S3;
Figure BDA00032088532200001310
and
Figure BDA00032088532200001311
respectively showing the included angles between the first section of connecting rod 19 and the second section of connecting rod 20, between the second section of connecting rod 20 and the third section of connecting rod 30, and between the third section of connecting rod 30 and the fourth section of connecting rod 29 in the ith control period; 1,2, ……。
In the first step of the embodiment, the combined center of mass m of the center of mass sensing element 18, the mechanical arm connecting rod and the upper platform 17 is determinedcPosition in coordinate system 0
Figure BDA00032088532200001312
The method comprises the following steps:
step one, initializing the position of an upper platform 17, and configuring the center of mass of the upper platform 17 and parts above the upper platform 17 at the center of a spherical air bearing rotor 24; the known centroid m1Has coordinates in the system {1} of
Figure BDA00032088532200001313
Centroid m2Has coordinates in the system {2} of
Figure BDA00032088532200001314
Centroid m3Has coordinates in the system {3} of
Figure BDA00032088532200001315
Centroid m4Has coordinates in the system {4} of
Figure BDA00032088532200001316
In order to facilitate the following coordinate transformation, the above four coordinates are rewritten into the following homogeneous coordinate form:
Figure BDA00032088532200001317
Figure BDA00032088532200001318
Figure BDA00032088532200001319
Figure BDA00032088532200001320
step one and two, calculating the mass center m1Coordinates of the position of (2) in the coordinate system {0}
Figure BDA00032088532200001321
Comprises the following steps:
Figure BDA00032088532200001322
in the formula:
Figure BDA00032088532200001323
wherein:
Figure BDA00032088532200001324
Figure BDA0003208853220000141
α, β, γ are X of the coordinate system {1} relative to the coordinate system {0}1、Y1、Z1Rotation angle of three axes, [ x ]1,y1,z1]TIs the position coordinate of the origin of the coordinate system {1} in the coordinate system {0 };
step one and three, calculating the mass center m2Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000142
Comprises the following steps:
Figure BDA0003208853220000143
in the formula:
Figure BDA0003208853220000144
wherein
Figure BDA0003208853220000145
Is the angle of rotation, [ x ] of the current second link 202,y2,z2]TIs the position coordinate of the origin of the coordinate system {2} in the coordinate system {1 };
step four, calculating the mass center m3Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000146
Comprises the following steps:
Figure BDA0003208853220000147
in the formula:
Figure BDA0003208853220000148
wherein, theta3Is the angle of rotation, b, of the present third link 301Represents a point O2And point O3The distance between them;
step one or five, calculating the mass center m4Coordinates of the position of (2) in the coordinate system {0}
Figure BDA0003208853220000149
Comprises the following steps:
Figure BDA00032088532200001410
in the formula:
Figure BDA00032088532200001411
wherein, theta4Is the angle of rotation, b, of the current arm link 4(29)2Represents a point O3And point O4Along the axis Z4A distance of l1Represents a point O3And point O4Along the axis X3The distance of (d);
step one six, calculating the mass center m1、m2、m3、m4Combined centroid mcPosition in coordinate System {0}
Figure BDA0003208853220000151
Figure BDA0003208853220000152
According to the centroid synthesis theorem, there are:
Figure BDA0003208853220000153
displacement of upper stage 17 under the coordinate system {0}
Figure BDA0003208853220000154
Comprises the following steps:
Figure BDA0003208853220000155
wherein h is the height of the center of the spherical air bearing rotor 24 relative to the lower surface of the lower stage 2, and the coordinate of the center of the spherical air bearing rotor 24 in the coordinate system {0} is [0,0, h ]]T。
And calculating the displacement according to the steps from one to six. The X-direction linear module, the Y-direction linear module and the Z-direction electric cylinder are controlled to move, so that the upper platform 17 and the parts above the upper platform are integrally displaced, and the combined mass center mcMoves to the center of the spherical air bearing rotor 24 to achieve center of mass adjustment. In this embodiment, controlling the movement of the Z-direction movement module and the XY-direction movement module according to the displacement includes:
step one seven, recording the radius of a transmission gear 11 of a driving motor in the X direction as
Figure BDA0003208853220000156
The radius of the X-direction linear module transmission gear 10 is
Figure BDA0003208853220000157
The lead of the X-direction linear module lead screw is
Figure BDA0003208853220000158
The angle omega of the rotation required by the X-direction linear module driving motor 6motor_xComprises the following steps:
Figure BDA0003208853220000159
assuming that the driving motor 6 of the X-direction linear module is a servo motor, and the servo motor works in a position mode, the number of pulses corresponding to one rotation of the motor is N1I.e. the motor rotates 1/N each time a pulse is sent to the motor1And (6) looping. Therefore, the number of pulses N sent to the X-direction linear module driving motor 6pul_xComprises the following steps:
Figure BDA0003208853220000161
wherein [ ] represents an integer.
If omegamotor_xIf the number is positive, the motor rotates forwards; if the number is negative, the motor rotates reversely. Sending N to the motorpul_xA number of pulses, the motor then drives the upper platform 17 on the axis X0Direction movement
Figure BDA0003208853220000162
Step one eight, recording the lead of the lead screw of the Y-direction linear module as ry1The angle ω of rotation required for the Y-direction linear module driving motor 16motor_yComprises the following steps:
Figure BDA0003208853220000163
assuming that the Y-direction linear module driving motor 16 isA servo motor working in a position mode, wherein the number of pulses corresponding to one rotation of the motor is N2I.e. the motor rotates 1/N each time a pulse is sent to the motor2And (6) looping. Therefore, the number of pulses N sent to the Y-direction linear module driving motor 16pul_yComprises the following steps:
Figure BDA0003208853220000164
wherein [ ] represents an integer.
If omegamotor_yIf the number is positive, the motor rotates forwards; if the number is negative, the motor rotates reversely. Sending N to the motorpul_yA number of pulses, the motor then drives the upper table 17 in the axis Y0Direction movement
Figure BDA0003208853220000165
Step one, as the upper platform 17 is driven to move by the electric cylinders in the Z direction, most of the electric cylinders support inputting instructions through RS232 or RS485 or CAN interfaces, and then the instructions are input
Figure BDA0003208853220000166
The push rod of the electric cylinder moves according to the command, thereby driving the upper platform 17 to move on the axis Z0Direction movement
Figure BDA0003208853220000167
Through steps one-to-nine, the combined center of mass of the upper platform 17 and the parts above it is moved to the center of the spherical air bearing rotor 24.
In the third step of the present embodiment, a simulation experiment is performed, and the equipment for a metamorphic core represented by a robot arm link starts to operate. Assuming the moment when the current control cycle is finished, the three angles of the mechanical arm connecting rod are respectively changed into three angles
Figure BDA0003208853220000168
And
Figure BDA0003208853220000169
and calculating the displacements of the X-direction linear module, the Y-direction linear module and the Z-direction electric cylinder in the current control period and controlling the displacements.
(1) Calculating the centroid m at the end of the current control period1Coordinates of the position of (a) in the system {0}
Figure BDA00032088532200001610
Comprises the following steps:
Figure BDA0003208853220000171
(2) calculating the centroid m at the end of the current control period2Coordinates of the position of (a) in the system {0}
Figure BDA0003208853220000172
Comprises the following steps:
Figure BDA0003208853220000173
(3) calculating the centroid m at the end of the current control period3Coordinates of the position of (a) in the system {0}
Figure BDA0003208853220000174
Comprises the following steps:
Figure BDA0003208853220000175
(4) calculating the centroid m at the end of the current control period4Coordinates of the position of (a) in the system {0}
Figure BDA0003208853220000176
Comprises the following steps:
Figure BDA0003208853220000177
(5) end of current control cycleTime, center of mass m1、m2、m3、m4Combined centroid mcPosition in coordinate System {0}
Figure BDA0003208853220000178
Note the book
Figure BDA0003208853220000179
According to the centroid synthesis theorem, there are:
Figure BDA00032088532200001710
(6) the displacement of the upper stage 17 in the coordinate system {0} is obtained
Figure BDA00032088532200001711
Comprises the following steps:
Figure BDA00032088532200001712
(7) in the current control period, the motion of the X-direction linear module, the Y-direction linear module and the Z-direction electric cylinder is controlled to ensure that the combined mass center mcMoves to the center of the spherical air bearing rotor 24 to achieve center of mass adjustment. The specific process is as follows:
calculating the number of pulses N input by the X-direction linear modulepul_xThe method comprises the following steps:
Figure BDA00032088532200001713
send N to the linear modulepul_xA pulse signal to make it move
Figure BDA00032088532200001714
② calculating the pulse number N of the control input of the Y-direction linear modulepul_yComprises the following steps:
Figure BDA00032088532200001715
send N to the linear modulepul_yA pulse signal to make it move
Figure BDA00032088532200001716
Thirdly, directly inputting the position instruction to the Z-direction electric cylinder through the communication interface
Figure BDA0003208853220000181
Make it move
Figure BDA0003208853220000182
Before the end of the current control period, the centroid mcIs relocated to the center of the spherical air bearing rotor 24.
The ith step: according to the moment when the ith control cycle is finished, the three angles of the mechanical arm
Figure BDA0003208853220000183
And
Figure BDA0003208853220000184
and repeating the calculation process of the step 3. Calculating the displacement of the X-direction linear module, the Y-direction linear module and the Z-direction electric cylinder in the ith control period
Figure BDA0003208853220000185
And
Figure BDA0003208853220000186
and controls its movement.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.

Claims (6)

1. The simulation method of the ground variable-centroid zero-gravity simulation device is characterized by comprising a base (1), a lower platform (2), a spherical air bearing seat (3), a spherical air bearing rotor (24), a middle platform (5), a Z-direction movement module, a linear module fixing platform (25), an XY-direction movement module, an upper platform (17), a centroid sensitive element (18), a mechanical arm connecting rod and a controller;
the spherical air bearing seat (3) is fixed on the base (1), the spherical air bearing rotor (24) is arranged on the spherical air bearing seat (3), the middle platform (5) is positioned above the spherical air bearing rotor (24), and air bearing can be formed between the middle platform (5) and the spherical air bearing rotor (24);
the lower platform (2) is positioned below the middle platform (5), the lower platform (2) is fixedly connected with the middle platform (5) through a support rod 23, the Z-direction movement module is arranged on the lower platform (2), the linear module fixing platform (25) is arranged on the Z-direction movement module, and the Z-direction movement module is used for driving the linear module fixing platform (25) to move in the vertical direction;
the XY direction movement module is arranged on the linear module fixing platform (25), the upper platform (17) is arranged on the XY direction movement module, and the XY direction movement module is used for driving the upper platform (17) to move on a horizontal plane;
the center-of-mass sensitive element (18) and the mechanical arm connecting rod are arranged on the upper platform (17) and are integrated;
the signal output end of the centroid sensing element (18) is connected with the signal input end of the controller, and the X, Y direction motion control signal output end of the controller is connected with the X, Y direction motion control signal input end of the XY direction motion module;
the Z-direction motion control signal output end of the controller is connected with the Z-direction motion control signal input end of the Z-direction motion module; the air injection control signal output end of the controller is connected with the air injection control signal input end of the spherical air bearing rotor (24);
in the simulation process, the controller controls the XY-direction motion module, the Z-direction motion module and the spherical air bearing rotor (24) to jet air according to the change of the center of mass detected by the center-of-mass sensing element (18), so that the center of mass of the integrated piece moves to the center of the spherical air bearing rotor (24) to realize center-of-mass adjustment;
the mechanical arm connecting rod comprises a first section of connecting rod (19), a second section of connecting rod (20), a third section of connecting rod (30) and a fourth section of connecting rod (29);
the mechanical arm connecting rod comprises a first section of connecting rod (19), a second section of connecting rod (20), a third section of connecting rod (30) and a fourth section of connecting rod (29);
the first section of connecting rod (19), the second section of connecting rod (20), the third section of connecting rod (30) and the fourth section of connecting rod (29) are sequentially and rotatably connected, and the first section of connecting rod (19) is fixed on the upper platform (17);
the XY direction movement module comprises two sets of X direction linear modules and two sets of Y direction linear modules;
the two sets of X-direction linear modules are placed on the linear module fixing platform (25) in parallel;
each set of X-direction linear module is provided with two X-direction linear module sliders, one set of X-direction linear module sliders on the same side of the two sets of X-direction linear modules is provided, each set of X-direction linear module sliders is fixed with one set of Y-direction linear module, and the four X-direction linear module sliders cooperatively drive the two sets of Y-direction linear modules to realize X-direction movement; each set of Y-direction linear module is provided with two Y-direction linear module sliding blocks, the upper platform (17) is fixed on the four Y-direction linear module sliding blocks, and the four Y-direction linear module sliding blocks cooperatively drive the upper platform (17) to realize Y-direction movement;
the method comprises the following steps:
s1, determining the combined mass center m of the mass center sensitive element (18), the mechanical arm connecting rod and the upper platform (17)cPosition in coordinate system 0
Figure FDA0003551995040000021
According to
Figure FDA0003551995040000022
The displacement of the upper platform (17) in the coordinate system {0} is calculated, and the movement of the Z-direction movement module and the XY-direction movement module is controlled according to the displacement, so as to integrate the mass center mcTo the center of the spherical air bearing rotor (24);
coordinate system {0} is coordinate system O0X0Y0Z0Plane X0O0Y0Is arranged on the lower surface of the base (1) and has an origin O0Is located at the center of the lower surface of the base (1) and has an axis X0Parallel to the X direction in the XY direction motion module, and the axis Z0The plumb is upward;
s2, ventilating the spherical air bearing seat (3), forming a layer of air film between the spherical air bearing seat (3) and the spherical air bearing rotor (24), lifting the spherical air bearing rotor (24), the upper platform (17), the centroid sensitive element (18) and the mechanical arm connecting rod in the air and freely rotating around the spherical center of the spherical air bearing rotor (24) to realize microgravity simulation, and starting the mechanical arm connecting rod to work;
s3, acquiring the angle of the mechanical arm connecting rod at the moment when the current control cycle is ended:
Figure FDA0003551995040000023
and
Figure FDA0003551995040000024
according to
Figure FDA0003551995040000025
And
Figure FDA0003551995040000026
obtaining a current combined centroid mcPosition in coordinate system 0
Figure FDA0003551995040000027
According to
Figure FDA0003551995040000028
Calculating the current control weekDisplacement of X-direction linear module, Y-direction linear module and Z-direction motion module in period
Figure FDA0003551995040000029
And
Figure FDA00035519950400000210
and controlling the movement thereof, i ═ i +1, repeating S3;
Figure FDA00035519950400000211
and
Figure FDA00035519950400000212
respectively showing the ith control cycle, and the included angles between the first section of connecting rod (19) and the second section of connecting rod (20), between the second section of connecting rod (20) and the third section of connecting rod (30), and between the third section of connecting rod (30) and the fourth section of connecting rod (29); 1,2, … …;
determining a combined mass center m of the mass center sensitive element (18), the mechanical arm connecting rod and the upper platform (17) in S1cPosition in coordinate system 0
Figure FDA00035519950400000213
The method comprises the following steps:
s11, establishing a coordinate system O0X0Y0Z0Coordinate system O1X1Y1Z1Coordinate system O2X2Y2Z2Coordinate system O3X3Y3Z3And a coordinate system O4X4Y4Z4The mass centers of the upper platform (17), the mass center sensitive element (18) and the first section of connecting rod (19) are recorded as m1The centroid of the second section of connecting rod (20) is recorded as m2The centroid of the third segment of the connecting rod (30) is recorded as m3The centroid of the fourth section of connecting rod (29) is recorded as m4(ii) a Determining centroid m1Has homogeneous coordinates in the coordinate system {1} of
Figure FDA0003551995040000031
Centroid m2Has homogeneous coordinates in the system {2}, of
Figure FDA0003551995040000032
Centroid m3Has homogeneous coordinates in the system {3}, of
Figure FDA0003551995040000033
Centroid m4Has homogeneous coordinates in the system {4}, of
Figure FDA0003551995040000034
Coordinate system O0X0Y0Z0Mid-plane X0O0Y0Is arranged on the lower surface of the base (1) and has an origin O0Is located at the center of the lower surface of the base (1) and has an axis X0Parallel to the direction of movement of the X-axis linear module, axis Z0Plumb-bob up, coordinate system O0X0Y0Z0Abbreviated as coordinate system {0 };
coordinate system O1X1Y1Z1Origin O1Is located at the center of the upper platform (17) and has an axis X1Parallel to the direction of movement of the X-axis linear module, axis Z1Plumb-bob up, coordinate system O1X1Y1Z1Abbreviated as coordinate system {1 };
coordinate system O2X2Y2Z2The origin of (A) is the intersection point of the rotation axis of the second link (20) relative to the first link (19) and the rotation axis of the third link (30) relative to the second link (20), and the axis Z2Is collinear with the rotation axis of the second section connecting rod (20) relative to the first section connecting rod (19), and the positive rotation direction is defined as an axis Z2Forward, coordinate system O2X2Y2Z2Abbreviated as coordinate system {2 };
coordinate system O3X3Y3Z3The origin of (2) is the intersection point of the axis of the third section of connecting rod (30) and the axis of the second section of connecting rod (20), and the axis Z3Connected to the second section opposite to the third section of the connecting rod (30)The axes of rotation of the rods (20) being collinear and defining a positive direction of rotation as axis Z3Forward direction; the axis and the axis X of the third section connecting rod (30)3Collinear, axis Z3And the axis Y2Co-directional and co-linear, coordinate system O3X3Y3Z3Abbreviated as coordinate system {3 };
coordinate system O4X4Y4Z4The origin of (A) is the intersection point of the axis of the fourth section of connecting rod (29) and the axis of the third section of connecting rod (30), and the axis Z4Is collinear with the rotation axis of the fourth section connecting rod (29) relative to the third section connecting rod (30), and the positive rotation direction is defined as an axis Z4Positive, axis Z4And axis X3Perpendicularly intersecting, axis Z4And axis Z3Parallel to the axis of the fourth link (29) and the axis Z4Collinear; coordinate system O4X4Y4Z4Abbreviated as coordinate system {4 };
s12, calculating the centroid m1Coordinates of the position of (2) in the coordinate system {0}
Figure FDA0003551995040000035
Comprises the following steps:
Figure FDA0003551995040000036
in the formula:
Figure FDA0003551995040000037
wherein:
Figure FDA0003551995040000041
Figure FDA0003551995040000042
alpha, beta and gamma are relative coordinate systems {1}X in a coordinate system {0}1、Y1、Z1Rotation angle of three axes, [ x ]1,y1,z1]TIs the position coordinate of the origin of the coordinate system {1} in the coordinate system {0 };
s13, calculating the centroid m2Coordinates of the position of (2) in the coordinate system {0}
Figure FDA0003551995040000043
Comprises the following steps:
Figure FDA0003551995040000044
in the formula:
Figure FDA0003551995040000045
wherein
Figure FDA0003551995040000046
Is the angle of rotation, [ x ] of the current second link (20)2,y2,z2]TIs the position coordinate of the origin of the coordinate system {2} in the coordinate system {1 };
s14, calculating the centroid m3Coordinates of the position of (2) in the coordinate system {0}
Figure FDA0003551995040000047
Comprises the following steps:
Figure FDA0003551995040000048
in the formula:
Figure FDA0003551995040000049
wherein, theta3Is the angle of rotation of the present third link (30)，b1Represents a point O2And point O3The distance between them;
s15, calculating the centroid m4Coordinates of the position of (2) in the coordinate system {0}
Figure FDA00035519950400000410
Comprises the following steps:
Figure FDA00035519950400000411
in the formula:
Figure FDA0003551995040000051
wherein, theta4Is the angle of rotation, b, of the present fourth link (29)2Represents a point O3And point O4Along the axis Z4A distance of l1Represents a point O3And point O4Along the axis X3The distance of (d);
s16, calculating the centroid m1、m2、m3、m4Combined centroid mcPosition in coordinate System {0}
Figure FDA0003551995040000052
Figure FDA0003551995040000053
According to the centroid synthesis theorem, there are:
Figure FDA0003551995040000054
displacement of upper platform (17) in coordinate system {0}
Figure FDA0003551995040000055
Comprises the following steps:
Figure FDA0003551995040000056
wherein h is the height of the center of the spherical air bearing rotor (24) relative to the lower surface of the lower platform (2), and the coordinate of the center of the spherical air bearing rotor (24) under a coordinate system {0} is [0,0, h]T。
2. The simulation method of the ground zero gravity simulation device with variable center of mass according to claim 1, wherein the step S1 of controlling the movement of the Z-direction movement module and the XY-direction movement module according to the displacement comprises:
s17, number of pulses N sent to X-direction linear module driving motor (6)pul_xComprises the following steps:
Figure FDA0003551995040000057
ωmotor_xrepresents the angle omega of the rotation required by the X-direction linear module driving motor (6)motor_xThe number of pulses corresponding to one rotation of the X-direction linear module driving motor (6) is N1，[]Expressing taking an integer;
if omegamotor_xIf the number is positive, the motor rotates forwards; if negative, the motor is reversed, and the X-direction linear module driving motor (6) can drive the upper platform (17) on the axis X0Direction movement
Figure FDA0003551995040000058
S18, number of pulses N sent to Y-direction linear module driving motor (16)pul_yComprises the following steps:
Figure FDA0003551995040000061
in the formula (2)]The number of pulses corresponding to one rotation of the linear module driving motor (16) in the Y direction is N2Y-direction linear module driveAngle omega of rotation required for motor (16)motor_y；
If omegamotor_yIf the number is positive, the motor rotates forwards; if negative, the motor is reversed and drives the upper platform (17) on axis Y0Direction movement
Figure FDA0003551995040000062
S19, the Z-direction movement module moves according to the instruction, thereby driving the upper platform (17) to move on the axis Z0Direction movement
Figure FDA0003551995040000063
3. The simulation method of the ground centroid-changing zero-gravity simulation device according to claim 2, wherein, in S17,
Figure FDA0003551995040000064
wherein the X-direction linear module adopts an X-direction driving motor transmission gear (11), an X-direction linear module transmission gear (10) and an X-direction linear module lead screw to realize the transmission of the X-direction linear module slide block,
Figure FDA0003551995040000065
represents the radius of a transmission gear (11) of the X-direction driving motor,
Figure FDA0003551995040000066
is the radius of the transmission gear (10) of the X-direction linear module,
Figure FDA0003551995040000067
the lead of the lead screw of the X-direction linear module is shown;
Figure FDA0003551995040000068
y-direction linear moduleThe transmission of the Y-direction linear module sliding block is realized by adopting a Y-direction linear module lead screw (14),
Figure FDA0003551995040000069
the lead of the Y-direction linear module lead screw (14) is shown.
4. The simulation method of the ground variable-centroid zero-gravity simulation device according to claim 1, wherein the Z-direction movement module comprises 4Z-direction electric cylinders (22);
4 electronic jar of Z direction (22) are fixed under on platform (2), sharp module fixed platform (25) are located between platform (2) and sharp module fixed platform (25) down, and the motion end of the electronic jar of 4Z directions (22) is connected with the bottom surface of sharp module fixed platform (25), and the motion of sharp module fixed platform (25) in vertical direction is realized in the electronic jar of 4Z directions (22) concerted motion.
5. The simulation method of the ground variable-centroid zero-gravity simulation device according to claim 4, further comprising two primary weights (21), wherein one primary weight (21) is suspended on each side of the lower platform (2), and the primary weights (21) are used for ensuring that the lower platform (2) is kept horizontal when the simulation is not started.
6. The simulation method of the ground variable-centroid zero-gravity simulation device according to claim 5, characterized by further comprising two secondary counterweights (4); two secondary counterweights (4) are respectively hung on two sides of the linear module fixing platform (25), and the secondary counterweights (4) are used for ensuring that the linear module fixing platform (25) is kept horizontal when simulation is not started.
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