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输入整形方法是一种根据结构振动特性对外力函数进行整形,以达到振动抑制效果的方法。本文以三连杆二关节的2自由度机械臂为例,详细推导了机械臂(逆)运动学和输入整形方法,设计了行程和输入整形函数,将整形后的动态响应与逆运动学方法的解析结果进行比较。研究结果表明:输入整形方法能有效抑制2自由度机械臂运行时的振动。该方法可以拓展到7自由度机械臂,针对柔性特征明显的空间站大型机械臂末端振动抑制也有直接参考意义,具备空间大型柔性结构基座机器人在轨精细控制的应用前景。 相似文献
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针对具有多轴天线驱动、机械臂运动、空间站舱段转位等多体运动特征的航天器,提出了一种基于浮动基座和树形拓扑结构的柔性多体动力学建模方法,用于计算机建模和与控制系统联合仿真。基于拉格朗日方程和有限元方法所建立的动力学方程考虑了大角度刚体相对转动、弹性部件振动、柔性关节变形特性。将此建模方法程序化并应用于工程实际,可解决此类航天器复杂的机构运动与弹性振动的耦合动力学建模问题,实现完全自主的动力学建模、模型代码输出和控制联合仿真功能,为此类航天器的动力学特性分析及其控制系统设计与系统级仿真验证服务。结合带多轴驱动天线和大型柔性天线的整星对象,采用该方法建模并就系统频率、频率响应、时间响应与商业柔性多体软件Adams进行对比,结果显示二者一致性良好,验证了该建模方法及其软件实现的正确性和通用性。 相似文献
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基于多臂自由飞行空间机器人多臂协调操使负载沿着期望的轨迹运动并且控制负载所受的内力为目的,在多臂自由飞行空间机器人系统协调操作的动力学方程基础上,推导了各个机械臂协调操作负载按期望轨迹运动时各个机械臂关节的驱动力矩的计算方法;给出了作用在负载的内力的定义,根据关节力矩计算方法和PID反馈控制原理,建立了多臂自由飞行空间机器人协调操作负载时的位置和内力的控制算法;讨论了所提出的控制算法的稳定性问题,得到了负载的位置误差和内力误差的约束条件。通过仿真实验证明该控制算法能够使负载的实际位姿和内力收敛到期望的轨迹和内力。 相似文献
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空间机械臂具有柔性大、振动频率低等特点,受激后振动的持续时间长、自然衰减慢。针对空间机械臂运行完成后留存的残余振动,采用固定界面子结构方法推导出关节转动与航天器-机械臂组合体振动的动力学显式关系。从中发现了控制关节转动并使其角速度正比于组合体振动的模态坐标,便能消耗组合体的机械能,加速组合体振动衰减的力学机理。据此,设计了逻辑关系简洁的机械臂关节角速度控制律,分别通过数值仿真和试验件实测对航天器-机械臂组合体的原理性模型开展了振动抑制效果的验证。结果表明:机械臂关节作动可以显著缩短受激后组合体残余振动的持续时间。 相似文献
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空间柔性臂的解耦动力学模型及其控制 总被引:1,自引:0,他引:1
提出了一种空间柔性结构通过关节电机同时实现轨迹控制和振动抑制的方法。针对单连杆空间柔性臂,采用非约束模态法建立了刚柔解耦动力学模型;提出了基于应变反馈的PID控制策略,并设计了PID/应变反馈复合控制器,同时实现对柔性臂末端运动轨迹的定位控制和弹性振动抑制控制;仿真结果验证了该控制策略的可行性。 相似文献
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针对刚柔耦合空间机械臂动力学建模中对柔性体采用的传统描述方法(有限元法、模态综合法以及集中参数法等)并不足以精确描述柔性大变形的问题,采用绝对节点坐标法描述柔性体,采用自然坐标法描述刚性体,建立了末端带集中质量的双连杆柔性机械臂的动力学模型并且研究了机械臂的空间定位问题。结合广义α法以及工程上常用的Scaling技术,开发了计算程序,实现了动力学方程的高效精确数值求解。针对机械臂的空间定位以及柔性变形问题,提出了一种运动规划方案,采用PD控制策略,实现了机械臂的运动跟踪控制;仿真结果表明:提出的运动规划方案能有效地减弱机械臂的柔性变形。 相似文献
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A computational methodology for analysis of space robot manipulator systems, considering the effects of the clearances in the joint, is presented. The contact dynamics model in joint clearance is established using the nonlinear equivalent spring-damp model and the friction effect is considered using the Coulomb friction model. The space robot system dynamic equation of manipulator with clearance is established. Then the dynamics simulation is presented and the dynamics characteristics of robot manipulator with clearance are analyzed. This work provides a practical method to analyze the dynamics characteristics of space robot manipulator with joint clearance and improves the engineering application. The computational methodology can predict the effects of clearance on space robot manipulator preferably, which is the basis of space robot manipulator design, precision analysis and ground test. 相似文献
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A preliminary analysis of the United States Laboratory (USL) module of the International Space Station has been completed. A major conclusion was that one of the most limited resources within the USL will be crew time. A laboratory robot would alleviate these constraints, improve safety, and reduce operational costs. A laboratory experiment manipulator system (LEMS) is proposed, made up of an on-board mobile manipulator and a computer-assisted operator control station. The on-board manipulator concept was tested with an Intelledex 660 industrial robot. Operator joystick command capability and delayed video feedback were added to simulate a Space Station Teleoperation system. The implementation of a unique predictive display was chosen for further evaluation because of its promise as a partial solution to the classical problem of robot remote control in the presence of time delay. The incorporation of various correction factors to calibrate the robot predictor model, including geometric distortion and spherical aberration caused by the video optics, is described. 相似文献
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六棱柱单元可展抛物面天线结构设计 总被引:4,自引:0,他引:4
本文提出了一个利用伸缩杆驱动的六棱柱展开单元,该单元可动机构数较少,展开可靠度高,结构刚度好,具有广泛的应用前景。利用伸缩杆六棱柱单元,文中设计了一大型构架式切割抛物面天线,并简要介绍了天线可展点的细部设计。该天线的形面精度较高,质量轻,造价低。 相似文献
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从机械臂运动学的角度,定义了故障容错机械臂、故障容错机械臂的阶、通用故障容错机械臂、特定任务故障容错机械臂,论证了通过运动学关节冗余也同样可以提高机械臂系统的可靠性、故障容错机械臂应该具备的自由度数、以及针对不同的任务要求来设计故障容错机械臂的方法。通过将任务空间抽象简化为一系列的特征点,建立与机械臂参数向理想值接近程度相关的罚函数,选择有效的优化算法,设计出了通用一阶故障容错平面位置机械臂、通用一阶故障容错空间位置机械臂、以及特定任务一阶故障容错平面位置机械臂。建立起完整的故障容错机械臂设计方法,对航天机器人的研究具有一定价值。 相似文献
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Chiara Toglia Marco Sabatini Paolo Gasbarri Giovanni B. Palmerini 《Acta Astronautica》2011,68(7-8):1031-1041
Space graspers are complex systems, composed by robotic arms placed on an orbiting platform. In order to fulfil the manoeuvres’ requirements, it is necessary to properly model all the forces acting on the space robot. A fully nonlinear model is used to describe the dynamics, based on a multibody approach. The model includes the orbital motion, the gravity gradient, the aerodynamic effects, as well as the flexibility of the links. The present paper aims to design, thanks to nonlinear optimization algorithms, a class of manoeuvres that, given the same target to be grasped, are characterized by different mission objectives. The grasping mission can be performed with the objective to minimize the power consumption. Collision avoidance constraints can be also added when the target is equipped with solar panels or other appendices. In some cases, large elastic displacements should be expected, possibly leading to an inaccurate positioning of the end-effector. Therefore, different design strategies can require that the manoeuvre is accomplished with minimum vibrations’ amplitude at the end-effector. Performance of the different strategies is analyzed in terms of control effort, trajectory errors, and flexible response of the manipulator. 相似文献