弱撞击空间对接机构及其主动柔顺控制的研究

发布时间：2019-02-12 10:15

【摘要】：相比于传统的被动缓冲式空间对接,弱撞击空间对接具有对接过程中接触力小、允许的初始位姿偏差大等优点,因此成为国际空间技术研究的热点。柔顺对接需要在对接过程中实时采集对接接触力,进行信号处理并完成位置命令修正,导致控制系统更加复杂;同时,由于弱撞击空间对接机构允许的对接初始条件更加恶劣,所以有必要选择合适的优化目标对空间对接机构进行优化设计。因此本文对弱撞击空间对接机构的优化设计方法以及柔顺控制策略进行了研究,为开展弱撞击空间对接进行理论储备。首先,为完成弱撞击空间对接模拟实验,本文以Stewart平台作为主动对接平台,在每个支链末端安装一维力传感器,用于采集对接过程中的接触力信息,完成其构型设计,进行其正逆运动学分析,其中正运动学采用数值迭代的方法完成,并完成其雅克比矩阵的推导,为后续的尺度综合和柔顺控制奠定了基础。为提高对接机构的综合性能,对基于雅克比矩阵和螺旋理论的并联机构的性能评价指标进行深入的对比分析,选定具有坐标系不依赖性和单位统一性优点的螺旋理论评价指标,利用其进行结构优化,并提出全局传递性能指标(GTIc)来评价确定工作空间条件下并联机构的传递性能。采用粒子群算法开展空间对接机构的尺度综合,为弱撞击对接机构的研制提供理论指导。基于此,进行对接机构的设计以及优化结果的验证。然后,为实现弱撞击空间对接,降低对接过程中的接触力,本文在传统阻抗控制的基础上,设计惯量-阻尼控制器,消除由于机器人末端操作器偏离期望位置而产生的恢复力,使机器人表现出对环境的完全适应性。此外,提出期望对接力解算方法,用以判定对接是否完成。并在此基础上,提出关节空间柔顺控制策略和笛卡尔空间柔顺控制策略来完成对接环位姿测量不精确条件下的弱撞击对接,采用MATLAB和ADAMS联合仿真方式验证两种控制策略的可行性,并对比分析其各自的优缺点。最后,设计3UPS-PS并联机构作为被动对接平台以构建对接模拟实验系统,完成其电气控制系统和软件控制系统的研制,对主动柔顺控制策略进行实验验证。完善了弱撞击空间对接实验流程,攻克力信号滤波、重力补偿、主被动对接环位姿测量等相关技术,并进行弱撞击空间对接模拟实验,验证控制策略的可行性。
[Abstract]:Compared with the traditional passive buffer space docking, the weak impact space docking has the advantages of small contact force in the docking process and large allowable initial position and attitude deviation, so it has become a hot spot in the international space technology research. In the process of docking, the docking contact force is collected in real time, the signal is processed and the position command is corrected, which makes the control system more complicated. At the same time, due to the worse initial conditions allowed by the weak impact space docking mechanism, it is necessary to select a suitable optimization target to optimize the design of the space docking mechanism. In this paper, the optimal design method and compliance control strategy of the weak impact space docking mechanism are studied in order to carry out the theoretical reserve for the weak impact space docking. First of all, in order to complete the simulation experiment of weak impact space docking, this paper takes the Stewart platform as the active docking platform, installs one dimensional force sensor at the end of each branch chain, which is used to collect the contact force information during the docking process and complete the configuration design. The forward and inverse kinematics analysis is carried out, in which the forward kinematics is completed by numerical iterative method, and the derivation of its Jacobian matrix is completed, which lays the foundation for the subsequent scale synthesis and compliance control. In order to improve the comprehensive performance of docking mechanism, the performance evaluation indexes of parallel mechanism based on Jacobian matrix and helical theory are compared and analyzed in depth, and the spiral theory evaluation index which has the advantages of independence of coordinate system and unity of unit is selected. The global transfer performance index (GTIc) is proposed to evaluate the transfer performance of the parallel mechanism under workspace conditions. Particle swarm optimization (PSO) is used to synthesize the scale of space docking mechanism, which provides theoretical guidance for the development of weak impact docking mechanism. Based on this, the design of docking mechanism and the verification of optimization results are carried out. Then, in order to realize the weak impact space docking and reduce the contact force in the docking process, the inertia damping controller is designed on the basis of the traditional impedance control to eliminate the recovery force caused by the robot terminal manipulator deviating from the desired position. The robot shows full adaptability to the environment. In addition, an expected pair of relay solution method is proposed to determine whether docking is complete or not. On this basis, the joint space compliance control strategy and the Cartesian space compliance control strategy are proposed to complete the weak impact docking under the condition of imprecise measurement of the docking ring position and attitude. The feasibility of the two control strategies is verified by MATLAB and ADAMS simulation, and their advantages and disadvantages are compared and analyzed. Finally, the 3UPS-PS parallel mechanism is designed as the passive docking platform to construct the docking simulation experiment system. The electrical control system and the software control system are developed, and the active compliance control strategy is verified experimentally. The experimental flow of weak impact space docking, force signal filtering, gravity compensation, active and passive docking ring position and attitude measurement are improved, and the simulation experiment of weak impact space docking is carried out to verify the feasibility of the control strategy.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：V441;TP242

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