月面采样钻具锁合随动式限幅机构研究

Research on unlockable servo stabilizer on lunar sampling drill

中国探月三期工程将采用无人探测器开展月面采样探测,利用中空外螺旋钻具开展预计深度为2m的连续钻取采样。在轨作业期间,航天器发射段和飞行段产生的随机振动负载及钻具在采样过程中存在的横向负载等附加负载会引起钻杆挠曲变形,严重时可能会导致钻取采样作业失败。在不修改取芯钻具的前提下,参考地面油田钻井工程中的相关技术,提出了一种月面采样钻具锁合随动式限幅机构。该机构主要由主支撑架、对接锁合组件和钢球锁释组件组成。在限幅机构工作过程中,其主支撑架在钻杆的中部位置提供外部支撑,减小由于飞行振动引起的挠曲变形,当钻具钻进一定深度后,对接锁合组件和钢球锁释组件实现锁合与解锁的功能,并随钻具同步向下进尺,为钻具后续的钻进动作提供空间。通过有限元分析手段,对限幅机构的强度和刚度进行校核与分析。通过试验件研制以及地面钻取采样试验验证可知:锁合随动式限幅机构作为外部支撑,能提高中空外螺旋钻具的刚度,且不会影响钻取采样的正常作业过程。研究结果表明锁合随动作业方式与当前取芯钻具的配合程度较好,提高了钻取采样作业性能及其可靠性,为完善我国探月三期工程钻取采样系统提供了参考。

An automatic drilling&sampling device will be used for Chinese lunar exploration mission,particularly a hollow outer spiral drill will be used in order to penetrate the lunar regolith in 2m depth continually.During the space environment,the flexure deformation increases by the additional load,such as the random vibration caused by launching or flighting of the spacecraftand the horizontal load caused by the drilling&sampling process,which complicates the load onthe lunar sampling drill.What's worse,it can cause the fault of the exploration mission.Instead of redesigning the lunar sampling drill,an unlockable servo stabilizer was designed for the lunar sampling drill,comparing with the drilling stabilizer in the oilfield drilling technology on the earth.The stabilizer was consisted of the main body frame,the ball locking structure and the docking&.locking structure.The main body frame could provide auxiliary support on the middle of the drill pipe in order to decrease the flexure deformation due to the vibration in orbit.When the drill had penetrated in a certain depth,the main body frame could be unlock by the ball locking structure and the docking&locking structure.The entire stabilizer penetrated with the lunar sampling drill,providing enough space for the penetration motion of the drilling and sampling system.Based on finite element method,the strength and stiffness of stabilizer had been tested.Combined with the drilling&sampling experiment with test article of the stabilizer,the unlockable servo stabilizer could improve the stiffness of the lunar sampling drill as an auxiliary support without obvious influence on the drilling&sampling process.The structure of the unlockable servo stabilizer operates well with sampling drill,which will improve the performance and reliability of the drilling&sampling process,and provide reference to improve the drilling&sampling system for Chinese lunar exploration mission.