Research On The Capacitive Attitude Measurement System Of The Floating Ball Platform

Floated-ball platform is a new type of frameless and high-precision inertial measurement platform.It has high measuring accuracy and strong adaptability because of the inner sphere and outer spherical structure.Attitude measurement system is the key component of floated-ball platform.This paper studies the capacitive attitude measurement system which is based on floated-ball platform.The work mainly includes the following aspects:1.Depended on capacitive attitude measuring principle,the measurement process of pitch and roll angle is analyzed and deduced.The difference of measuring yaw angle is to separately measure base and essence value of yaw angle and then add them to obtain the final value.2.According to the principle of angle measurement,continuous attitude simulation model is established.The effects of plate spacing between attitude strips and width of receiving belt on electric capacity are investigated in favor of simulation analysis.Besides,the phase contrast of output electric signal and relationship between the position of motivation and the output signal phase difference are also studied.The results show that the width of the receiving belt and capacitance will be greater with the decrease of the attitude plate placing.The output signal phase difference has a corresponding linear relationship to the position of motivation activator.The space between two conductors of continuous distribution structure will lead to a large blind area when measuring the yaw angle.3.Improving on the basis of the continuous activator,the paper also studies the incentive structure of two kinds of discrete belt,The activator model with uncrossed and crossed discrete structure is established respectively.The output attitude angle,attitude error signal and the measurement linearity of yaw angle on four different positions of the motivation belt are analyzed by simulation.The comparison results demonstrates that the phase difference output from four positions of two discrete structure has similar trend.Overall,the average error of uncrossed discrete structure is small.In respect of measuring exact value of yaw angle,the output phase difference of uncrossed discrete structure has great linearity,which has a small angle measurement blind area.4.Comparing the advantages and disadvantages of continuous incentive band and uncrossed discrete incentive structure,the uncrossed discrete band incentive band is taken for designing reference.It can be found that uncrossed incentive band has strong anti-jamming capability when adding noise interference.Besides,the change of incentive signal frequency has no effect on the system,The overall structure diagram and working mechanism of capacitive attitude measurement system is introduced.Moreover,the merits and flaws of the entire system is analyzed and improving methods are put forward.