Development Of Moment Of Inertia Measurement System For A Certain Cabin

In aerospace field, the moment of inertia (MOI) is one of the most important factors, which directly affects the performance of product like flight attitude and stability etc. MOI must be measured precisely in order to check if it meets the design requirements. In this paper, the measurement system is developed to measure the MOI of the cabin sections for a certain missile.The system adopts the method of torsion pendulum. Photoelectric timing method is used to realize the measurement of period. That's to say, the photoelectric sensor abstracts the oscillation period signal, which is collected to the computer by high-accuracy data acquisition card, and the value of period can be calculated by the software. Finally, the MOI measuring value can be calculated according to the measuring principle of torsion pendulum. The paper finished the design of overall structure, studied the measurement flow and deduced the mathematical model of MOI.The hardware of the system includes the mechanical part and the electricity part. The description of mechanical parts includes the design of measure system's mechanical equipment, the working principle and advantage of air-floating turning platform, the design of torsion bar and the choice of micro-tremor architectural. The electricity part detailed introduces the controlling element and the timing element, and makes a research on the realization of the controlling function and the period measurement using data acquisition card.The software for measurement system is established to accomplish turning platform controlling, period measuring and MOI calculating automatically. This thesis briefly introduces the software design thread that needs pay attention to.At last, the research analyzes and synthesizes the factors which cause MOI measurement errors. Based on the comparative experiment with mass property instrument of US Space Electronics and the period repetitive experiment, the measuring accuracy is above 0.1%, it is concluded that this system meets the requirements.