FAST馈源支撑系统位姿分配方法研究

为实现五百米口径球面射电望远镜(Five-hundred meter Aperture Spherical radio Telescope,FAST)馈源支撑系统馈源终端的高精度轨迹跟踪及防止馈源支撑索力超限,研究了馈源支撑系统星形框架和AB轴机构对目标终端位姿的分配算法。首先,根据馈源支撑系统机构特征,综合馈源舱的重心时变及其采用的回照策略,建立了带有馈源舱回照策略的考虑馈源舱重心时变的悬索牵引并联系统力学模型。然后,为解决AB轴机构与星形框架间的运动耦合问题,设计了两种馈源支撑系统位姿分配算法:优先保障六索索力均衡的位姿分配算法和优先保障馈源接收终端定位精度的位姿分配算法。最后,通过仿真对两种算法在馈源终端定位精度和索力分布情况两个方面的性能进行分析。仿真结果表明:前一算法能使六索索力分配均匀,但是引入了最大1.2°的馈源接收终端指向误差,已超出工程指向精度范围。后一算法的六索索力波动较大,但索力没超限或虚牵,能保证馈源接收终端的位姿,此算法满足工程需求。

Research on pose distribution algorithm of FAST feed support system

In order to achieve high-accuracy trajectory tracking at feed end of Five-hundred meter Aperture Spherical radio Telescope (FAST) support system and to prevent the force over-limit of supporting cables,the pose distribution algorithms of target end by the star-frame of feed support system and A-B rotator were studied in the article.Firstly,according to the mechanism characteristic of the feed support system,combining the time-varying barycenter and the back illuminating strategy applied in feed cabin,a mechanical model of cable-driven parallel system which considers the time-varying barycenter of feed cabin and provided with back illuminating strategy was established.Secondly,in order to solve the motion coupling between the A-B rotator and the star-frame,two pose distribution algorithms of the feed support system were designed:the pose distribution algorithm which gives priority on ensuring the balanced cable force of six-cable and the pose distribution algorithm which gives priority on ensuring the positioning accuracy of the feed receiver.Finally the performance of above two algorithms on positioning accuracy of the feed receiver and the distribution of cable force were analyzed.And the results show that the former algorithm is able to balance the cable force on six-cable,however the error due to introduction of maximum 1.2° of the feed receiver has been beyond the scope of the specified accuracy of the project.The second algorithm makes cable force on six-cable fluctuate significantly,but the force was not over the limit or under virtual pull,which means such algorithm meets engineering requirements because it can ensure the pose of the feed receiver.