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15 System Testing and Validation Technology of Lunar Lander
15.7.3 Design of Test System
The test system for engine thrust pulsation effect on GNC sensors was composed
of the lunar rover test model, gravity compensation subsystem of near zero stiffness spring, pulsation thrust exciter and input control system, and measurement
subsystem, as shown in Fig. 15.15.
1. Test Model of the Lunar Lander
The real main structure and real landing gears were applied and the mass property
of the lunar lander during landing on lunar surface should be simulated. The flight
models of concerned GNC navigation sensors should be on the test model.
2. Gravity Compensation Subsystem of Near Zero Stiffness Spring
The metal spring is general elastic element and can be used as a gravity compensation
unit to constitute gravity compensation subsystem. The basic principle of gravity
compensation with springs was: With the spring’s stiffness characteristics, under the
load gravity, the elastic recovery force by elastic deformation of the spring would
balance the load gravity; at the same time, the load mass and the spring constitute
Fig. 15.15 Configuration of test system for engine thrust pulsation effect on GNC sensors 1 Ring;
2 Beam; 3 Gravity compensation subsystem of near zero stiffness spring; 4 the lunar rover test
model; 5-Pulsation thrust interaction interfaces; 6 Pulsation thrust exciter and input control system;
7 Exciter support; 8 Ground.