阅读说明：本技术 应用于大空间绳驱系统的物体转动惯量测量方法 (Object rotational inertia measuring method applied to large-space rope driving system ) 是由 姚蔚然 卢彦岐 吴立刚 孙光辉 刘健行 于 2021-08-20 设计创作，主要内容包括：应用于大空间绳驱系统的物体转动惯量测量方法,属于绳驱机器人装配及测量领域,本发明为解决现有测量物体转动惯量和装配物体必须采用两套设备实现,过程与设备过于繁琐的问题。本发明方法：S1、将被装配物体G-(2)安装在工装N上装配在绳驱系统上,8根绳索对称设置；S2、将质心配到旋转轴Z-(0)上；S3、绕Z-(0)轴进行简谐振动；S4、在简谐振动过程中,实时采集被测量物体在水平面绕Z-(0)轴的转角θ,并根据该转角θ控制调整8根绳索的张力值；S5、记录每根绳索的简谐运动周期,并将8根绳索的简谐运动周期平均值作为被测量物体做简谐振动的周期；S6、获取被装配物体G-(2)绕Z-(0)轴的转动惯量J-(2)。(The invention discloses an object rotational inertia measuring method applied to a large-space rope driving system, belongs to the field of assembly and measurement of rope driving robots, and aims to solve the problems that the existing method for measuring the rotational inertia of an object and assembling the object is implemented by two sets of equipment, and the process and the equipment are too complicated. The method comprises the following steps: s1, object G to be assembled 2 The device is arranged on a tool N and assembled on a rope driving system, and 8 ropes are symmetrically arranged; s2, fitting the center of mass to the rotation axis Z 0 The above step (1); s3, winding Z 0 Carrying out simple harmonic vibration on the shaft; s4, acquiring the Z-axis of the measured object in the horizontal plane in real time in the simple harmonic vibration process 0 The rotation angle theta of the shaft is controlled and adjusted according to the rotation angle theta, and the tension values of 8 ropes are controlled and adjusted; s5, recording the simple harmonic motion period of each rope, and taking the average value of the simple harmonic motion periods of 8 ropes as the period of the measured object to perform simple harmonic vibration; s6, obtaining the assembled object G 2 Around Z 0 Moment of inertia J of shaft 2 。)

1. The method for measuring the rotational inertia of the object applied to the large-space rope driving system is characterized by comprising the following steps of:

s1, object G to be assembled₂Is installed on a tool N and then is assembled with an object G₂The tool N is assembled on the rope drive system, 8 ropes of the rope drive system are symmetrically arranged, and the tool N is positioned in the center of a working space of the rope drive system;

s2, assembling the tool N and the assembled object G through the counterweight device on the tool N₂The centre of mass of the whole being coupled to the axis of rotation Z₀Upper, tool N and assembled object G₂The whole is taken as a measured object;

s3, rotating the measured object at the initial rotation angle theta in the horizontal plane by controlling 8 ropes₀After that, start winding around Z₀The shaft is subjected to simple harmonic vibration, and the simple harmonic vibration is that the measured object is enabled to wind around Z in the horizontal plane by controlling the tension of 8 ropes₀The shaft rotates periodically;

s4, acquiring the Z-axis of the measured object in the horizontal plane in real time in the simple harmonic vibration process₀The rotation angle theta of the shaft is controlled and adjusted according to the rotation angle theta, and the tension values of 8 ropes are controlled and adjusted;

s5, recording the simple harmonic motion period of each rope, and taking the average value of the simple harmonic motion periods of 8 ropes as the period T of the measured object for simple harmonic vibration_1ave；

S6, according to the formula

Obtaining an assembled object G₂Around Z₀Moment of inertia J of shaft₂；

Wherein A is the torsional constant of the rope drive system, J₀For N winding Z of the tool₀The rotational inertia of the shaft.

2. The method for measuring the rotational inertia of an object applied to a rope drive system in a large space according to claim 1, wherein the object G to be assembled is processed in step S1₂Procedure for fitting on rope drive system:

rope outlet point C arranged at eight vertex angles of working space of rope driving system₁～C₈Are respectively connected with the assembled object G through 8 ropes₂Eight rope pulling points P₁～P₈The upper No. 1 rope to the lower No. 4 rope and the lower No. 5 rope to the lower No. 8 rope are symmetrical relative to the horizontal plane, and the left side 4 ropes and the right side 4 ropes are symmetrical relative to the vertical plane;

establishing world coordinate system O by taking working space center of rope drive system as origin₀-X₀Y₀Z₀To be assembled with an object G₂Establishing a world coordinate system O with the center as an origin₁-X₁Y₁Z₁The two coordinate system origins coincide.

3. The method for measuring the rotational inertia of an object applied to a rope drive system in a large space according to claim 2, wherein the assembled object G is collected in real time in S4₂Around Z in the horizontal plane₀The process of controlling and adjusting the tension values of 8 ropes according to the rotation angle theta of the shaft comprises the following steps:

the tension values of the above 4 ropes are the same: f₁＝F₂＝F₃＝F₄

The following 4 ropes have the same tension values: f₅＝F₆＝F₇＝F₈

No. 1 rope tension value F₁Obtained as follows:

in the formula: x'₁,y′₁,z′₁Is number 1 rope vector l₁Vector element of (1), rope vector l₁Obtained as follows:

(x_c01,y_c01,z_c01) For simple harmonic vibration process, a rope outlet point C₁Relative to O₀-X₀Y₀Z₀Coordinates of a coordinate system;

l, w and h are the length, width and height of the measured object;

m is the mass of the measured object, and g represents the gravity acceleration;

k is the restoring force coefficient of the rope driving system in simple harmonic vibration;

no. 5 rope tension value F₅Obtained as follows:

in the formula: x'₅,y'₅,z'₅Is number 5 rope vector l₅Vector element of (1), rope vector of number 5,/₅Obtained as follows:

(x_c05,y_c05,z_c05) For simple harmonic vibration process, a rope outlet point C₅Relative to O₀-X₀Y₀Z₀Coordinates of a coordinate system.

4. The method for measuring the rotational inertia of an object applied to a rope drive system in a large space according to claim 3, wherein the period T of the simple harmonic vibration in S5_1aveThe acquisition process of (1):

obtaining the simple harmonic vibration period T of each 1 rope through the variation curve of the length of each rope_i1,2,3,4,5,6,7,8, the period T of simple harmonic oscillation_1avePush buttonAnd (6) obtaining.

5. The method for measuring the rotational inertia of an object applied to a rope driving system in a large space according to claim 4, wherein the torsion constant A of the rope driving system is obtained by the following steps:

to-be-assembled object G₂Replacement with a standard object G₁Performing the steps S1-S5, and then according to the formula

The torsion constant a is obtained.

6. The method for measuring the rotational inertia of an object applied to a large-space rope driving system according to claim 1, wherein the Z-axis of the measured object in the horizontal plane is acquired in real time₀The rotation angle θ of the axis is realized by a motion capture system including at least four motion capture cameras disposed facing the measured object from at least four directions.

Technical Field

The invention relates to a method for measuring the rotational inertia of an assembly object in a large-space rope-driven assembly process, and belongs to the field of assembly and measurement of rope-driven robots.

Background

With the rapid development of economy, industry and aerospace industry, the problem of large-space assembly gradually becomes a main assembly problem, and the large-space assembly also becomes a main research direction and has very wide practical application. At present, large-space mechanical arms or a gantry crane and the like are adopted for assembly work in large-space assembly, but the rigid connecting rods or brackets are easy to cause body damage due to overlarge torque in the large space, so that the assembly task fails and even the danger of injuring field personnel is caused. The unique flexibility characteristics of the rope can better solve the problems of the rigid objects, so that the rope has the feasible implementation of large-space assembly, and the large-space assembly by using the rope driving device gradually becomes a development trend. The rope drive assembly system is characterized in that a set of rope winding device is respectively arranged at eight top corners of a large space, wherein each set of rope winding device comprises a motor and a rope winding and unwinding device. Eight ropes extend out from eight vertex angles in the large space and are symmetrically connected to 8 connection points of an object to be assembled, the release and the contraction of the ropes are controlled by controlling the torque value of the motor, and finally the tail end assembling object is controlled to move to a specified assembling position.

During the assembly process, it is necessary to measure mass characteristics of the assembled object, such as the moment of inertia of the object. Only by knowing the moment of inertia of each individual assembled object can the moment of inertia of the whole assembled object be obtained, and subsequent research and application can be carried out. These conventional methods for measuring the rotational inertia of an object require a separate measuring platform and corresponding measuring equipment.

During the assembly process of the large-space rope drive, the rotational inertia of the assembled object is measured. However, the conventional measurement method is mainly based on a torsional pendulum method, and the rotational inertia of the object can be measured only by using specific measurement equipment to make the object vibrate in simple harmonic mode and measuring parameters such as a motion period. Therefore, in the traditional large-space rope driving assembly process, the assembled object needs to be measured through a specific measuring device, and then the assembly task is carried out through the rope driving device. The whole process needs one set of measuring equipment and one set of assembly equipment, and the process and the equipment are too complicated.

Disclosure of Invention

The invention aims to solve the problems that the existing method for measuring the rotational inertia of an object and assembling the object must be realized by two sets of equipment, and the process and the equipment are too complicated, and provides an object rotational inertia measuring method applied to a large-space rope driving system. The measuring of the rotational inertia can be completed in the assembling process by using the rope driving device to measure the rotational inertia, and two tasks of measuring the rotational inertia and assembling can be efficiently and independently completed by using one set of device. Meanwhile, the rotational inertia is measured in the assembling process, and the rotational inertia of the assembled object can be obtained more accurately because the assembled object is in an actual working state.

The invention discloses an object rotational inertia measuring method applied to a large-space rope driving system, which comprises the following steps of:

s1, object G to be assembled₂Is installed on a tool N and then is assembled with an object G₂The tool N is assembled on the rope drive system, 8 ropes of the rope drive system are symmetrically arranged, and the tool N is positioned in the center of a working space of the rope drive system;

s2, assembling the tool N and the assembled object G through the counterweight device on the tool N₂The centre of mass of the whole being coupled to the axis of rotation Z₀Upper, tool N and assembled object G₂The whole is taken as a measured object;

s3, rotating the measured object at the initial rotation angle theta in the horizontal plane by controlling 8 ropes₀After that, start winding around Z₀The shaft is subjected to simple harmonic vibration, and the simple harmonic vibration is that the measured object is enabled to wind around Z in the horizontal plane by controlling the tension of 8 ropes₀The shaft rotates periodically;

s4, acquiring the Z-axis of the measured object in the horizontal plane in real time in the simple harmonic vibration process₀The rotation angle theta of the shaft is controlled and adjusted according to the rotation angle theta, and the tension values of 8 ropes are controlled and adjusted;

s5, recording the simple harmonic motion period of each rope, and taking the average value of the simple harmonic motion periods of 8 ropes as the period T of the measured object for simple harmonic vibration_1ave；

S6, according to the formula

Obtaining an assembled object G₂Around Z₀Moment of inertia J of shaft₂；

Wherein A is the torsional constant of the rope drive system, J₀For N winding Z of the tool₀The rotational inertia of the shaft.

Preferably, the object to be assembled G in step S1₂Procedure for fitting on rope drive system:

rope outlet point C arranged at eight vertex angles of working space of rope driving system₁～C₈Are respectively connected with the assembled object G through 8 ropes₂Eight rope pulling points P₁～P₈The upper No. 1 rope to the lower No. 4 rope and the lower No. 5 rope to the lower No. 8 rope are symmetrical relative to the horizontal plane, and the left side 4 ropes and the right side 4 ropes are symmetrical relative to the vertical plane;

establishing world coordinate system O by taking working space center of rope drive system as origin₀-X₀Y₀Z₀To be assembled with an object G₂Establishing a world coordinate system O with the center as an origin₁-X₁Y₁Z₁The two coordinate system origins coincide.

Preferably, the assembled object G is acquired in real time in S4₂Around Z in the horizontal plane₀The process of controlling and adjusting the tension values of 8 ropes according to the rotation angle theta of the shaft comprises the following steps:

the tension values of the above 4 ropes are the same: f₁＝F₂＝F₃＝F₄

The following 4 ropes have the same tension values: f₅＝F₆＝F₇＝F₈

No. 1 rope tension value F₁Obtained as follows:

in the formula: x'₁,y′₁,z′₁Is number 1 rope vector l₁Vector element of (1), rope vector l₁Obtained as follows:

(x_c01,y_c01,z_c01) For simple harmonic vibration process, a rope outlet point C₁Relative to O₀-X₀Y₀Z₀Coordinates of a coordinate system;

l, w and h are the length, width and height of the measured object;

m is the mass of the measured object, and g represents the gravity acceleration;

k is the restoring force coefficient of the rope driving system in simple harmonic vibration;

no. 5 rope tension value F₅Obtained as follows:

in the formula: x'₅,y′₅,z′₅Is number 5 rope vector l₅Vector element of (1), rope vector of number 5,/₅Obtained as follows:

(x_c05,y_c05,z_c05) For simple harmonic vibration process, a rope outlet point C₅Relative to O₀-X₀Y₀Z₀Coordinates of a coordinate system.

Preferably, the period T of the simple harmonic vibration in S5_1aveThe acquisition process of (1):

obtaining the simple harmonic vibration period T of each 1 rope through the variation curve of the length of each rope_i1,2,3,4,5,6,7,8, the period T of simple harmonic oscillation_1avePush buttonAnd (6) obtaining.

Preferably, the torsion constant a of the rope drive system is obtained by:

to-be-assembled object G₂Replacement with a standard object G₁Performing the steps S1-S5, and then according to the formula

The torsion constant a is obtained.

Preferably, the real-time acquisition is carried out on the measured object in the horizontal plane around Z₀The rotation angle θ of the axis is realized by a motion capture system including at least four motion capture cameras disposed facing the measured object from at least four directions.

The invention has the beneficial effects that:

(1) the traditional method for measuring the rotational inertia of the object is simplified and optimized, and a separate measuring device for the rotational inertia is not needed.

(2) The rotary inertia measuring task of the assembled object and the assembling task of moving the assembled object to a desired position in a cross-space mode can be completed by using one set of rope driving equipment, the task which can be realized by adding one set of traditional measuring device and one set of assembling device is realized, the use cost is reduced, the work efficiency is improved, the flow of integral assembly is greatly simplified, and the flexibility of the integral assembling system is improved.

(3) The measurement of the rotational inertia of the object is completed in the assembling process because the actual working state of the object to be assembled is closer to the assembling process, so that the measured rotational inertia is more suitable for an actual assembly body.

Drawings

FIG. 1 is a schematic structural diagram of an object rotational inertia measurement method applied to a large-space rope drive system according to the invention;

FIG. 2 is an enlarged view of a portion of FIG. 1;

fig. 3 is a graph of tension control rate analysis of rope nos. 1 and 5;

FIG. 4 is an enlarged view of a portion of FIG. 3;

fig. 5 is a flow chart of the method for measuring the rotational inertia of an object applied to a large-space rope driving system.

Detailed Description

The first embodiment is as follows: the present embodiment is described below with reference to fig. 1 to 5, and the method for measuring the rotational inertia of an object applied to a large-space rope drive system in the present embodiment includes the following steps:

s1, object G to be assembled₂Is installed on a tool N and then is assembled with an object G₂The tool N is assembled on the rope drive system, 8 ropes of the rope drive system are symmetrically arranged, and the tool N is positioned in the center of a working space of the rope drive system;

s2, assembling the tool N and the assembled object G through the counterweight device on the tool N₂The centre of mass of the whole being coupled to the axis of rotation Z₀Upper, tool N and assembled object G₂The whole is taken as a measured object;

s3, rotating the measured object at the initial rotation angle theta in the horizontal plane by controlling 8 ropes₀After that, start winding around Z₀The shaft is subjected to simple harmonic vibration, and the simple harmonic vibration is that the measured object is enabled to wind around Z in the horizontal plane by controlling the tension of 8 ropes₀The shaft rotates periodically;

s4, acquiring the Z-axis of the measured object in the horizontal plane in real time in the simple harmonic vibration process₀The rotation angle theta of the shaft is controlled and adjusted according to the rotation angle theta, and the tension values of 8 ropes are controlled and adjusted;

s5, recording the simple harmonic motion period of each rope, and taking the average value of the simple harmonic motion periods of 8 ropes as the period T of the measured object for simple harmonic vibration_1ave；

S6, according to the formula

Obtaining an assembled object G₂Around Z₀Moment of inertia J of shaft₂；

Wherein A is a ropeTorsional constant of the drive system, J₀For N winding Z of the tool₀The rotational inertia of the shaft.

With reference to the flow chart shown in fig. 5, the process of obtaining the torsional constant a of the rope drive system:

to-be-assembled object G₂Replacement with a standard object G₁Performing the steps S1-S5, and then according to the formula

The torsion constant a is obtained.

An object G to be assembled in step S1₂Procedure for fitting on rope drive system:

rope outlet point C arranged at eight vertex angles of working space of rope driving system₁～C₈Are respectively connected with the assembled object G through 8 ropes₂Eight rope pulling points P₁～P₈The upper No. 1 rope to the lower No. 4 rope and the lower No. 5 rope to the lower No. 8 rope are symmetrical relative to the horizontal plane, and the left side 4 ropes and the right side 4 ropes are symmetrical relative to the vertical plane;

establishing world coordinate system O by taking working space center of rope drive system as origin₀-X₀Y₀Z₀To be assembled with an object G₂Establishing a world coordinate system O with the center as an origin₁-X₁Y₁Z₁The two coordinate system origins coincide.

The relationship of the two coordinate systems is explained with reference to fig. 1. Wherein O is₀-X₀Y₀Z₀World coordinate system, O, for the large assembly space (rope drive system working space)₁-X₁Y₁Z₁Is a coordinate system established by the center of the tool. P₁，P₂，P₃，P₄，P₅，P₆，P₇，P₈As a rope pulling point of the tool, C₁，C₂，C₃，C₄，C₅，C₆，C₇，C₈And connecting a rope outlet point of the tool for the rope driving system. The length of the measured object is l, the width is w and the height is h. O is_p1，O_p2，O_p3，O_p4Representing 4 motion capture cameras, together forming a set of motion capture systems.

The 8 ropes that the symmetry set up distribute into 4 ropes in top, 4 ropes in bottom. The top 4 ropes and the corresponding bottom 4 ropes are symmetrically distributed relative to the horizontal plane. The 4 ropes on the left side and the corresponding 4 ropes on the right side are symmetrically distributed relative to the vertical plane. Therefore, when considering the rope tension control rate, the corresponding top rope and bottom rope can be considered as one group, and the ropes are divided into 4 groups (1 rope and 5 rope, 2 rope and 6 rope, 3 rope and 7 rope, 4 rope and 8 rope) in the invention. When the rotation of the measured object around the Z axis is considered, only the tension changes of the No. 1 rope at the top and the No. 5 rope at the bottom corresponding to the top are considered, and the other three groups of ropes are consistent with the change conditions of the ropes.

Around the object to be measured Z₀The tension control rate of No. 1 rope and No. 5 rope when the axle is simple harmonic motion, the tension control rate of other three groups of ropes is rather than unanimous, No. 2 rope, No. 3 rope, the tension control rate of No. 4 rope is unanimous with No. 1 rope control rate, No. 6 rope, No. 7 rope, the tension control rate of No. 8 rope is unanimous with No. 5 rope control rate. Fig. 3 is a graph showing the tension control rate analysis of the ropes No. 1 and No. 5.

Next, the tension control of the No. 1 rope and the No. 5 rope shown in fig. 3 will be described. The center point of the measured object is O₀Relative to O₀-X₀Y₀Z₀The coordinates of the coordinate system are (0,0, 0).

When the rope driving equipment pulls the tool, the rope outlet point C_i(i ═ 1,5) relative to O₀-X₀Y₀Z₀The coordinates of the coordinate system are (x)_c0i,y_c0i,z_c0i) Wherein c is the rope outlet point of the meter, 0 represents O₀-X₀Y₀Z₀The established world coordinate is a reference system, and i represents a few ropes connected with the tool.

Rope pulling point P_i(i ═ 1,5) relative to O₀-X₀Y₀Z₀Of a coordinate systemThe coordinate is (x)_p0i,y_p0i,z_p0i) Wherein p represents the rope pulling point and 0 represents O₀-X₀Y₀Z₀The established world coordinate is a reference system, and i represents a few ropes connected with the tool.

Rope pulling point P_i(i ═ 1,5) relative to O₁-X₁Y₁Z₁The coordinates of the coordinate system are (x)_p1i,y_p1i,z_p1i) Wherein p represents the rope pulling point and 1 represents O₁-X₁Y₁Z₁The coordinate system established is a reference system, i represents the several ropes connecting the tool.

θ₁₅Is the 1 st rope vector l₁The angle between the rope and the horizontal plane is the 5 th rope vector l₅The included angle with the horizontal plane.

l_1xoyIs the 1 st rope vector l₁Projection in the horizontal plane, /)_5xoyIs the 5 th rope vector l₅Projection in the horizontal plane.

l_i(i is 1,5) is the ith rope from the rope outlet point C_iPoint of traction of the rope P_iVector of (2) relative to O₀-X₀Y₀Z₀The coordinate of the coordinate system is (x'_i,y′_i,z′_i) The angle between the ith rope vector and the horizontal plane is theta_i(i-1, 5) and the tension value on the ith rope is F_i(i＝1,5)。

a_i(i-1, 5) is selected from O₀-X₀Y₀Z₀The origin point of the coordinate system points to the ith rope outlet point C_iVector of (2) relative to O₀-X₀Y₀Z₀The coordinates of the coordinate system are (x)_c0i,y_c0i,z_c0i)。

b_i(i-1, 5) is selected from O₀-X₀Y₀Z₀The origin of the coordinate system points to the i-th rope pulling point P_iVector of (2) relative to O₀-X₀Y₀Z₀The coordinates of the coordinate system are (x)_p0i,y_p0i,z_p0i)。

(1) MeterCalculating rope pulling point P₁,P₅Relative to O₀-X₀Y₀Z₀Coordinates (x) of a coordinate system_p01,y_p01,z_p01)，

(x_p05,y_p05,z_p05) This is obtained by the following formula:

wherein

(2) Calculate the 1 st rope vector l₁And the 5 th rope vector l₅It can be obtained by the following formula:

(3) calculate the 1 st rope vector l₁And the 5 th rope vector l₅Angle theta with horizontal plane₁And theta₅。

By the above-mentioned two rope vectors l₁And l₅The included angle theta between the rope vector and the horizontal plane can be respectively obtained₁And theta₅Meanwhile, because the spatial disposition is symmetrical, the following equation is used:

the following can be concluded:

θ₁＝θ₅

thus putting two rope vectors l₁And l₅The angle in the horizontal plane is denoted as θ₁₅This can be obtained from the following equation:

(4) calculating the force arm l of the component force of the 1 st rope and the 5 th rope in the horizontal plane_xoy。

l_xoyIs the center point O of the measured object₀Projected point O on horizontal plane_0xoy(0,0) to the 1 st rope vector l₁Projection on a horizontal plane l_1xoy＝(x′₁,y′₁) And C₁Projection C in the horizontal plane_1xoy＝(x_c01,y_c01) The distance of the straight line formed.

Establishing a linear equation:

the finishing is simplified to obtain:

y′₁x+x′₁y+x′₁y_c01-y′₁x_c01＝0

then l can be obtained from the following formula_xoy：

(5) Calculate root 1Tension value F of the rope₁And tension value F of the 5 th rope₅Sum of component forces F in the horizontal plane_xoy。

Because the moment of inertia of an object rotating around the Z axis needs to be measured, a rope is needed to drive the object to rotate around the Z axis in the horizontal plane₀The axes being in simple harmonic motion, thus F_xoyThe following equation needs to be satisfied:

f can be obtained from the following formula_xoy：

K is the restoring force coefficient of the rope driving system in simple harmonic vibration, and a unit numerical value is generally selected. I.e. a positive number from 1 to 9, the coefficients can be selected according to the mass size of the object to be measured. The larger the quality the larger the selection coefficient value should be.

(6) Calculated to satisfy the winding Z of the measured object₀The tension values F of the ropes 1 and 5 are set under the condition that the shafts do simple harmonic motion₁And F₅The ability of the tension value to change with theta is analyzed.

The tension values of the above 4 ropes are the same: f₁＝F₂＝F₃＝F₄

The following 4 ropes have the same tension values: f₅＝F₆＝F₇＝F₈

Respectively establishing a force balance equation in the horizontal direction and the vertical direction:

where m represents the mass of the object being measured and g represents the acceleration of gravity.

F can be derived from the following equation by the above equation₁And F₅Tension value of (2):

further finishing to obtain:

the expression is a relation between the No. 1 (No. 5) rope and the angle theta around the Z axis, and the measured object is rotated by the initial angle theta on the horizontal plane from S3₀After that, start winding around Z₀The shaft carries out simple harmonic vibration, in the simple harmonic vibration process, the motion capture system monitors the change of the rotation angle, and the rotation angle theta is collected and substituted into the formula to calculate F₁Value of (A), F₅According to F₁＝F₂＝F₃＝F₄、F₅＝F₆＝F₇＝F₈The tension value of 8 ropes is obtained according to the relation, and each rope is controlled to control the motor to work according to the tension value. According to the relation, the turning angle is collected in real time, the tension value of the rope is controlled and changed in real time, and the rope is made to stretch so as to realize that 8 ropes pull the measured object to perform simple harmonic vibration and complete measurement.

One implementation is given below in conjunction with fig. 5.

The first step is as follows: a standard object G₁A motion capture system (such as an optitrack motion capture system) installed on the tool N and adjusted in the working space, and the rotation angle theta of the measured object at each moment can be measured by the motion capture system_i(i represents the ith time).

The second step is that: tool N and tool N are connected through counterweight device on tool NStandard object G₁The centre of mass of the whole being coupled to the axis of rotation Z₀And the measured object is prevented from generating horizontal translation when rotating, and 8 ropes are controlled to move the object to the center of the working space, so that the symmetry of the 8 ropes is ensured.

The third step: after 8 ropes are controlled to rotate the measured object at the initial rotation angle theta on the horizontal plane, the rotation inertia measuring mode is started, namely the real-time rotation angle data fed back by the motion capture system is used for controlling the tension control rate of each rope to be the given tension control rate, and the measured object can be ensured to wind Z on the horizontal plane₀The shaft does simple harmonic vibration. Meanwhile, the motion capture system provides an external measurement means for rope driving control, and the assembly precision can be further improved. When the object does simple harmonic vibration, the length change of each rope is measured and recorded through an encoder on a control motor of each rope, and the simple harmonic motion period T of the object can be solved through the change curve of the length of each rope_i(i ═ 1,2,3,4,5,6,7,8), by calculating the simple harmonic motion period T of 8 ropes_iThe average value of (i ═ 1,2,3,4,5,6,7,8) is taken as the period T of the simple harmonic motion of the measured object_1ave。

The fourth step: according to the object being measured in the horizontal plane Z₀The shaft does simple harmonic motion, and the torsion constant A of the rope drive device can be obtained by the following formula. N-winding Z of tool₀Moment of inertia of the shaft J₀(known amount). Standard object G₁Around Z₀Moment of inertia of the shaft J₁(known amount).

The fifth step: to-be-assembled object G₂A motion capture system (such as an optitrack motion capture system) installed on the tool N and adjusted in the working space, and the rotation angle theta of the measured object at each moment can be measured by the motion capture system_i(i represents the ith time).

And a sixth step: tool N and a workpiece are assembled through a counterweight device on the tool NAccessory G₂The centre of mass of the whole being coupled to the axis of rotation Z₀And the measured object is prevented from generating horizontal translation when rotating, and 8 ropes are controlled to move the object to the center of the working space, so that the symmetry of the 8 ropes is ensured.

The seventh step: after 8 ropes are controlled to rotate the measured object at the initial rotation angle theta on the horizontal plane, the rotation inertia measuring mode is started, namely the real-time rotation angle data fed back by the motion capture system is used for controlling the tension control rate of each rope to be the given tension control rate, and the measured object can be ensured to wind Z on the horizontal plane₀The shaft does simple harmonic vibration. Meanwhile, the motion capture system provides an external measurement means for rope driving control, and the assembly precision can be further improved. When the object does simple harmonic vibration, the length change of each rope is measured and recorded through an encoder on a control motor of each rope, and the simple harmonic motion period T of the object can be solved through the change curve of the length of each rope_i(i ═ 1,2,3,4,5,6,7,8), by calculating the simple harmonic motion period T of 8 ropes_i(i is 1,2,3,4,5,6,7,8) as the period T of the simple harmonic vibration of the measured object_2ave。

Eighth step: according to the object being measured in the horizontal plane Z₀The axis does simple harmonic motion, and the rotational inertia J of the assembled object can be obtained by the following formula₂。

Measuring the winding X of the assembled object if necessary₀Axis and Y₀The rotational inertia of the axis can be measured by artificially turning the assembled object.