基于电磁场原理的航天器变频吸振技术

Spacecraft adaptive vibration absorber based on electronic magnetic field

为了有效抑制航天器转动部件对敏感载荷的扰动,将电磁技术应用于变频吸振器上,从经典电磁理论出发,建立了斥力悬浮型电磁变频装置的数学模型。该型电磁变频装置通过两个电磁铁对中间的永磁体产生排斥作用来产生恢复力:当中间永磁体偏离平衡位置时,由于两边电磁铁斥力的非线性变化使得二者对中间永磁体产生一个指向平衡位置的恢复力。理论分析表明,在气隙不大的情况下,该力与永磁体偏离平衡位置的位移成正比,同时其与电磁铁中通入的电流成正比关系,进一步的仿真也验证了该结论,这为有效、精确控制变频吸振器的工作频率提供了理论依据。根据理论计算和有限元仿真,采用了电磁技术的变频装置可以提供4 500 N/m左右的刚度变化范围,应用该变频装置的吸振器可以提供近50 Hz的频率变化范围,同时其调节速度和精度也能满足航天器对变频吸振器相关性能的要求。

The rotating parts on the spacecraft can seriously disturb working payload. In order to decrease this effect, electronic magnetic technology was applied to adaptive vibration absorber. This EM frequency control system worked through the repulsions from two electromagnets： when the central magnet left the balance place, repulsions of the electromagnets on both sides of the magnet would change. Because of the nonlinearity of the repulsions, the combining force would point to the balance just like a restoring force.Theoretical analysis showed that if the distance between the two electromagnets was sufficiently small,such restoring force was proportional to the displacement of central magnet from the balance place. Furthermore, it was also proportional to the currency in the electromagnet. These conclusions are supported by simulation too. That means it can be taken as the base of an effective, high-accurate DVA control method. According to the theoretical calculation and FEM simulation results, the whole system can change its stiffness in a range of 4 500 N/m. Through choosing right mass ratio, the adaptive vibration absorber could adjust its working frequency in a range of 50 Hz. The performance of the vibration absorber can meet the need of spacecraft.