空间绳网捕获后绳系组合体张力控制技术研究

发布时间：2018-01-07 21:34

本文关键词：空间绳网捕获后绳系组合体张力控制技术研究　出处：《浙江大学》2015年博士论文　论文类型：学位论文

【摘要】：空间绳网捕获是近年提出的一种新型柔性抓捕方式,具有抓捕容错性强、作业距离长及飞行器间耦合作用弱等优点,具有广阔的应用前景,是近年来空间研究的热点之一。空间绳网捕获系统涉及到力学、机械、电气、控制及材料等多个学科,在总体方案设计、动力学分析及控制系统设计等多个方面都存在较多的科学问题需要研究。空间绳网捕获系统捕获目标物的工作过程主要可分为任务平台跟瞄、接近、绳网发射、网口锁紧和位姿调整等过程。目标物捕获后可根据需要再动作,一般主要有拖曳、离轨等动作过程。任务平台和目标物是通过系绳连接的,系绳长度和张力的控制由安装在任务平台上的张力控制机构实现,可对目标物进行回收、释放和状态保持。但张力控制过程相对复杂,如绳网收口锁紧目标物后,任务平台和目标物仍是两分散的刚体系统,要通过系绳的收、放或张力保持等操作使任务平台与目标物之间实现动量交换或能量耗散,使两刚体的运动速度尽量保持一致,实现两刚体的有效连接,避免冲击、摆动、缠绕等问题的出现。鉴于国内外对这方面的研究不多,本论文在国家863计划项目和国家自然科学基金资助下,以空间绳网捕获后的绳系组合体为研究对象,针对上述张力问题,主要的研究工作和相应成果如下：(1)提出了一种多功能、高效能的系绳张力控制机构。通过论证空间绳网捕获后系统可能存在的多种运动现象,对张力控制机构提出了系绳姿态角、绳长及张力等方面的功能需求,据此研制了张力控制机构样机,并分析讨论了张力控制机构的张力跟踪等各类静、动态性能。(2)建立了考虑任务平台与目标物自身姿态及系绳二次非线性弹性的绳系组合体普遍动力学模型,进行了摆振耦合分析。根据组合体普遍动力学模型,仿真研究系统多个运动自由度之间的耦合情况,分析各种初始扰动对组合体运动的影响。利用摄动法给出了系统动力学简化模型的近似解析解,得到了系统稳态运行时产生内共振的条件,为绳网捕获系统的设计提供了理论基础。(3)提出了一种防冲击防缠绕的组合体协调控制策略。建立包含张力控制机构机电系统及目标物姿态的系统机电耦合模型,为防止目标物捕获后的初始速度带来的冲击、系绳缠绕等问题,根据模型特点,提出了一种系绳张力与目标物转矩协调控制方法。数值仿真表明：在目标物只存在初始平动及同时存在初始平动与转动两种情形下,控制策略都是充分有效的。研制了地面气浮实验平台,进行了目标物初始平动情形下的防冲击缓冲释放实验,取得了良好的控制效果,验证了控制方法和技术的有效性。(4)提出了一种组合体面内摆动抑制方法。借鉴秋千激荡原理的逆向思维,提出了一种面内摆动抑制控制方法,对地面恒重力场下的摆动系统进行了研究,数值仿真与实验验证了所提出的摆动抑制策略的有效性。进一步,将方法推广应用于空间绳系系统,数值仿真验证了此摆动抑制策略对空间绳系组合体的适用性。(5)研究了Kevlar系绳纵向非线性特性及扭转耗散特性,提出了一种目标物被动消旋方法。设计了系绳纵向吊挂试验方案,试验表明系绳纵向刚度存在很强的非线性,利用三次函数和幂函数分别对试验结果进行了拟合,取得了良好的拟合效果。纵向加减载试验表明系绳存在较明显的迟滞效应,利用Kawabata应力—应变模型对试验结果进行了拟合,同样取得了良好的拟合结果。开展了系绳扭转试验,根据试验结果利用弹簧阻尼模型研究了系绳扭转耗散规律与扭转过程中的纵向缩短特性,着重研究了系绳扭转刚度与阻尼与系绳长度及系绳张力大小的关系。另外,针对捕获后绳系组合体绕系绳轴线方向存在的自旋运动问题,提出了利用扭转过程耗散能量的机构实现目标物被动消旋的方法,试验验证了方法的有效性。
[Abstract]:Net capture is a new flexible way to arrest put forward in recent years, with the arrest of fault tolerance, long distance working vehicle and the coupling between the weak and other advantages, has broad application prospects, is one of the hot research in recent years. Net capture system involves mechanics, mechanical, electrical, control and multi discipline materials, in the overall design scheme, dynamic analysis of scientific problems in many aspects and control system design are more need to study. The working process of net capture system to capture the target can be divided into task tracking platform, close to the net emission process of net mouth locking and posture adjustment. Things captured according to the need for action, which mainly has the drag deorbit action process. Task platform and target is connected through a tether, control tether length and tension by the installation in Ren Wuping The tension control mechanism on the platform, can be recycled to the target, and maintain the state of release. But the tension control process is relatively complex, such as closing rope locking the target, task and target platform is still the two dispersed rigid body system, through a tether, or other operations so that the implementation of the tension maintaining momentum exchange or the energy dissipation between task and target platform, the moving speed of two rigid bodies as consistent as possible, to achieve the effective connection of two rigid bodies to avoid shock, swing, wind and other issues. In view of the domestic and international research in this area is not much, this thesis is supported by the National 863 project and National Natural Science Fund. The rope combined net capture the body as the research object, aiming at the problem of tension, the main research work and corresponding results are as follows: (1) proposed a versatile, efficient tether tension control machine Structure. Through a variety of motion phenomena may prove the existence of net capture system, the tension control mechanism put forward the tether attitude angle, functional requirements and other aspects of the length of the rope tension, the tension control mechanism is developed, and discuss the tension tracking and other kinds of tension control mechanism of the static and dynamic performance. (2 a rope) combination of general dynamics model of attitude and task and target platform tethers two nonlinear elastic considerations, the pendulum vibration coupling analysis. According to the combination of general dynamics model, the coupling between multiple degrees of freedom of motion simulation system, analysis of various initial disturbance influence on body movement. By using the perturbation method gives the approximate analytical solution of the system dynamics model, the steady-state operation generated when internal resonance conditions, provides for the design of net capture system On the basis of. (3) proposed a combination of anti shock anti winding coordinated control strategy is established. The electromechanical coupling system model of tension control mechanism of electromechanical system and target attitude, in order to prevent the initial velocity of the object after the capture of the impact problem of tether winding, according to the characteristics of the model, put forward the control method a tether tension and target torque coordination. Numerical simulation shows that only exists in the initial target of translation and the translation and rotation and the initial two cases, the control strategy is effective. The development of ground air experimental platform, the target under the condition of initial translational anti shock buffer release experiment achieved a good control effect, verify the effectiveness of the proposed control method and technology. (4) proposed a method to suppress in-plane swing. From the reverse thinking principle put forward swing agitation. A plane swing suppression control method of ground swing system with constant gravity field is studied, the numerical simulation and experiments verify the effectiveness of the proposed suppression strategy swing. Further, the method is applied to the space tethered system, the numerical simulation verifies the applicability of this swing suppression strategy for space rope the combination of body. (5) studied the longitudinal nonlinear characteristics of Kevlar tether and torsion dissipation characteristics, proposes a target passive despinning method is designed. The longitudinal tether hanging test plan, test shows that tether longitudinal stiffness is nonlinear strong, respectively, the results were fitted using cubic function and exponential function and achieved good fitting results. Longitudinal load tests show that tether hysteresis effect obviously, using the Kawabata model of the stress and strain of the test results were also obtained a good fitting. Good fitting results. The tether torsion test, according to test results using spring damping model of tether torsion dissipation and longitudinal shortening characteristics of torsion in the process, focusing on the torsional stiffness and damping between the tether and tether length and tether tension. In addition, the captured tethered spin motion combination around the axis of the tether, the method of using reverse process energy dissipation mechanism to realize the target of passive racemization, test and verify the validity of the method.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：V52

【相似文献】