Research On Measuring Method Of Moment Of Inertia For Large Object With Complex Structures

In the aerospace field,the moment of inertia is very important for the aircraft’s control.With the development of high-precision technology,more precise control on large aircraft is needed,and inertia measurement technology for large-scale complex structure are also need to be promoted.New measurement equipment is becoming more and more high precision,integrated and automated.Now the MOI measurement of large-scale complex structure is low security,ineffective and tooling difficult.In this paper.In this paper,the measurement scheme of the equivalent torsion pendulum method and the vibration pendulum method is proposed for measuring the large-scale complex structure yaw direction and the pitch-roll direction’s MOI.After analyzing the traditional measurement method,the equivalent torsional pendulum method is put forward to measure MOI in yaw direction.Horizontal measurement method is more safe.The airfoil support technology is also introduced to greatly reduce the contact friction,and the single-degree-of-freedom spring is used as the excitation source,forming a huge torque spring force in the center,the equivalent torsion pole as a excitation source.In this way,the large objects’ vibration difficulty was solved,and torsion pendulum’s high non-linearity problem is also solved.For MOI in the pitching-roll direction,a rotational inertia measurement scheme based on the vibration pendulum method was took out,solving the tooling difficulty of large complex structure.We use symmetrical distribution of spring group as a excitation source.Give a pure moment to the vibration platform,and then the platform excites.It will do complex pendulum movement under the spring force and gravity.In this paper,a movement modeling was built,resolving the principle of the complex pendulum movement,doing some simulation of possible error factors.At last,some initial conditions ensuring the accurate measurement was gave.In the measurement scheme proposed in this paper,the airfoil support technology is introduced.It would greatly improve the measurement feasibility and measurement accuracy.When researching float technology,the gas model is simplified and the gas in the air bearing is simplified as one-dimensional flow.Based on the equation,we designed the gas foot used in our equipment.At last,simulation software to simulation verification was Introduced.At the end of this paper,the measurement scheme proposed in this paper is compared with the simulation results and experimental data to verify the feasibility of the measurement scheme.