13.4 Application of Special Measurement Technology
453
lander, with the leakage rage of 1 × 10
−3 Pa•m
3 /s. Such technology had also been
successfully applied in other spacecraft integration and assembly process in China.
13.4.5 Mass Property Test of Lunar Lander with Multiple
DOF Transformation
1. Requirements
The traditional mass property test of spacecraft, generally bracket in L shape was
applied in the test of longitudinal mass center and inertia. During test, there were
complex operation processes including lift of spacecraft and docking with L shape
bracket. Compared with general spacecraft, the configuration of the lunar lander
was complex and the size of envelope was large. Therefore, the traditional L shape
bracket could not meet requirements of mass property test. For example, if the L
shape bracket was applied in test of longitudinal mass center of the lunar lander, it
was impossible to install deployable mechanisms such as landing gears and solar
panels. The final mass property should be calculated further, which could seriously
affect test accuracy. Meanwhile, the test of the inertia could be implemented with L
shape bracket.
The linear three-coordinate converter could implement the mass property test with
multiple Degree of Freedom transformation, which could meet the test requirements
and avoid the complex operation processes of re-lifting and docking.
2. Technical Design and Principle
The mass property test technology of multiple DOF transformation was to establish
the position relationship between the lunar lander coordinate system and the test
coordinate system by the three-coordinate converter instead of L shape bracket.
The longitudinal mass center and inertia of spacecraft could be tested by rotation
adjustment of the three-coordinate converter.
The structure of the three-coordinate converter is shown in Fig. 13.14, which was
composed of lathe bed, rotation table, inclined platform, lower bracket and ballast
mechanism. The rotation table, inclined platform, lower bracket and inclined shaft
were referred to as slide table. The slide table was connected with the lathe bed by
guide track and can move horizontally along the guide track on the lathe bed. The
lunar lander was installed on the rotation table and could be rotate around the center
of inclined platform at 360°. The inclined table could be inclined at a certain angle
along the inclined shaft. The lathe bed could support the weight of the lunar lander,
slide table and ballast mechanism, whose bottom was docked with the mass property
test bed.
The idea of mass property test technology with multiple DOF transformation was
to compare the change of lateral mass center of the lunar lander in different status,
so as to calculate the longitudinal mass center of the lunar lander.
The specific testing process is as follows [14].
453
lander, with the leakage rage of 1 × 10
−3 Pa•m
3 /s. Such technology had also been
successfully applied in other spacecraft integration and assembly process in China.
13.4.5 Mass Property Test of Lunar Lander with Multiple
DOF Transformation
1. Requirements
The traditional mass property test of spacecraft, generally bracket in L shape was
applied in the test of longitudinal mass center and inertia. During test, there were
complex operation processes including lift of spacecraft and docking with L shape
bracket. Compared with general spacecraft, the configuration of the lunar lander
was complex and the size of envelope was large. Therefore, the traditional L shape
bracket could not meet requirements of mass property test. For example, if the L
shape bracket was applied in test of longitudinal mass center of the lunar lander, it
was impossible to install deployable mechanisms such as landing gears and solar
panels. The final mass property should be calculated further, which could seriously
affect test accuracy. Meanwhile, the test of the inertia could be implemented with L
shape bracket.
The linear three-coordinate converter could implement the mass property test with
multiple Degree of Freedom transformation, which could meet the test requirements
and avoid the complex operation processes of re-lifting and docking.
2. Technical Design and Principle
The mass property test technology of multiple DOF transformation was to establish
the position relationship between the lunar lander coordinate system and the test
coordinate system by the three-coordinate converter instead of L shape bracket.
The longitudinal mass center and inertia of spacecraft could be tested by rotation
adjustment of the three-coordinate converter.
The structure of the three-coordinate converter is shown in Fig. 13.14, which was
composed of lathe bed, rotation table, inclined platform, lower bracket and ballast
mechanism. The rotation table, inclined platform, lower bracket and inclined shaft
were referred to as slide table. The slide table was connected with the lathe bed by
guide track and can move horizontally along the guide track on the lathe bed. The
lunar lander was installed on the rotation table and could be rotate around the center
of inclined platform at 360°. The inclined table could be inclined at a certain angle
along the inclined shaft. The lathe bed could support the weight of the lunar lander,
slide table and ballast mechanism, whose bottom was docked with the mass property
test bed.
The idea of mass property test technology with multiple DOF transformation was
to compare the change of lateral mass center of the lunar lander in different status,
so as to calculate the longitudinal mass center of the lunar lander.
The specific testing process is as follows [14].