主动补偿式超低干扰力矩气浮转台的设计

由于微纳卫星反作用飞轮的输出力矩与气浮转台的干扰力矩属于同一量级,故无法直接采用气浮转台实现微纳卫星姿态动力学仿真及姿控系统的地面试验验证。为了解决这一问题,设计并研制了主动补偿式超低干扰力矩气浮转台。对气浮转台的干扰力矩进行分析,提出了3种减小干扰力矩的方法:通过优化设计,降低了黏滞阻尼力矩;通过配置斜向节流孔,并单独供气,产生大小可调的主动涡流以抵消气浮轴承的固有涡流,从而降低涡流力矩;利用气浮轴承的摆动特性实现高精度平衡调节,减弱了重力诱导力矩。最后,设计了微小力矩测量装置,测量了剩余干扰力矩并基于测试结果来指导涡流力矩和重力诱导力矩补偿过程。测试结果显示:气浮转台实现的干扰力矩小于5×10-5 Nm,小于反作用飞轮的最小输出1×10-4 Nm,满足微纳卫星姿态动力学及控制的地面验证需求。

Design of supper low disturbance torque air bearing table with active compensation

As the output moments of reaction wheels for micro-satellites and nano-satellites are the same as the disturbance moment of an Air Bearing Table (ABT), the attitude dynamic simulation and ground test of the micro-satellites and nano-satellites can not be implemented directly by the ABT. To solve the problems, an active compensation ABT with a supper low disturbance moment was designed and developed. The disturbance moment of the ABT was analyzed and three kinds of methods to reduce the disturbance moment were proposed. Firstly, the viscous damping moment was reduced by optimizing design; Then, the vertex moment was reduced by setting sloping slant orifices to generate an active vertex to balance the inherent vertex of the air bearing, and to reduce the inherent vertex moment. Finally, the swing characteristics of air bearing was used to implement high precise balance adjustment and to reduce the gravity induced moment. A measuring device of micro-moment was designed and the remaining vertex moment was measured and the measuring results were used to direct the compensation of the vertex moment and gravity induced moment. Experimental results indicate that the disturbance moment of the ABT is smaller than 5×10^-5 Nm, which is less than the minimum output moment(1×10^-4 Nm) of the reaction wheel. Obtained results satisfy the requirements of the ground simulation of attitude dynamics and the control of micro-satellites and nano-satellites.