大型深空测控天线副反射面控制技术

针对大口径、高频段深空测控天线主/副反射面变形引起的天线电性能下降问题,采用副反射面控制技术实现天线的电性能补偿。首先,在分析并联机构数学模型的基础上,结合并联机构坐标系定义,给出六自由度并联机构位姿的正、逆解;其次,根据变形后天线形状采用抛物面拟合法给出副反射面位姿与仰角的关系,这样在天线实时运动过程中,可根据仰角查找出副反射面位姿最佳工作点;最后通过六自由度并联机构正、逆解及控制算法控制副反射面到最佳位置和姿态上。理论分析和工程实践表明,副反射面控制技术通过控制副反射面中心到最佳焦点位姿上,可实现对天线电性能的有效补偿。六自由度并联机构控制具有自身承载力强,位置、姿态控制灵活等特点,适合于大型天线副反射面实时精密控制。

Subreflector Control Technology for Large Deep Space TT&C Antennas

Subreflector control technology was used to realize antenna electrical performance compensation for electrical performance degradation caused by deformation of the main reflector and subreflector of a large aperture high frequency deep space Tracking, Telemetry and Command (TT&C) antenna. Following analysis of the mathematical model of a parallel mechanism, the forward and inverse solutions of the position and attitude of the 6-Degree Of Freedom (6-DOF) parallel mechanism were given by definition of a parallel mechanism coordinate system. Then, according to the deformed shape, the relationship between the position and attitude of subreflector and the pitch angle was given using parabolic fitting method, and the best working point of the subreflector position and attitude were found out against the pitch angle in realtime motion process. Finally, control of the subreflector to the best position and attitude was realized by the 6-DOF parallel mechanism forward and inverse solutions and control algorithm. Theoretical analysis and engineering practices show that the control technology of the subreflector can achieve effective compensation for antenna electrical performance by controlling the centre point of the subreflector to reach the best position and attitude. Strong bearing capacity and flexible control features of position and attitude and the 6-DOF parallel mechanism of the subreflector can achieve realtime precise control.