Distributed Manipulation Using Discrete Actuator Arrays
Distributed Manipulation Using Discrete Actuator Arrays
复制标题
使用离散执行器阵列进行分布式操纵
DOI：
10.1177/02783640122067543
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
H. Choset
中科院分区：
文献类型：
--
作者：
J. Luntz;W. Messner;H. Choset
分布式操纵系统通过应用许多外力诱导对象上的动作。执行器阵列使用许多合作操纵较大物体的平面元素（称为单元）的平面阵列进行分布式操作。通常，高度致密的执行器阵列被建模为在空间连续的可编程力场上，尽管实现相对较少的执行器支持对象，并且连续的假设破裂。本文有两个目的：介绍一种在高度离散的执行器阵列上建模和分析操纵动力学的方法，并提出一种针对离散执行器阵列设计操纵策略的方法。这是在特定的宏观执行器阵列中完成的，该阵列包括固定的电动车轮平面阵列。动力学的建模考虑了执行器与对象之间相互作用的几个模型，对象之间的重量在支持之间的重量分布以及系统的离散性质。在某些建模假设下，对于给定的一组支撑单元，对象的操作动力学非常简单。这些分段连续动力学的反转产生了完全连续的开环操作策略，从而有效地平息了不连续性。作者表明，尽管所得的操作场可能会稳定地定位并在连续场情况下定位任何对象，但离散性会导致许多对象经历不稳定的旋转平衡。因此，较差的方向精度是使用离散执行器阵列进行开环操作的限制，并激发了反馈的使用。作者还通过反转离散动力学来得出闭环操纵策略，这些动力学将许多输入的三输出分布式控制问题降低到在分布式控制下运行的标准三输入，三输出控制问题。实际上，执行器的数组被简化为能够在对象上施加所需的净力和力矩的单个虚拟执行器。事实证明，即使在存在动态耦合和由于离散性引起的非线性的情况下，这些闭环策略在渐近稳定。多媒体扩展包括完整的模拟器和实验原型的视频。
Distributed manipulation systems induce motions on objects through the application of many external forces. An actuator array performs distributed manipulation using a planar array of many small stationary elements (which are called cells) that cooperate to manipulate larger objects. Typically, highly dense actuator arrays are modeled as spatially continuous, programmable forcefields, althoughinmany implementations a relatively small number of actuators supports an object and continuous assumptions break down. This paper serves two purposes: to present a methodology for modeling and analyzing the dynamics of manipulation on a highly discrete actuator array and to present a methodology for designing manipulation strategies on discrete actuator arrays. This is done in the context of a particular macro-scale actuator array comprising a fixed planar array of motorized wheels. Modeling of the dynamics takes into account several models of the interaction between the actuators and the object, the distribution of the weight of the object among the supports, and the discrete nature of the system. Under certain modeling assumptions, the manipulation dynamics of an object are extremely simple for a given set of supporting cells. An inversion of these piecewise-continuous dynamics generates a fully continuous open-loop manipulation strategy, effectively smoothing out the discontinuities. The authors show that although the resulting manipulation field may stably position and orient any object in the continuous field case, discreteness causes many objects to experience unstable rotational equilibria. Thus, poor orientation precision is a limitation of open-loop manipulation using discrete actuator arrays and motivates the use of feedback. The authors also derive closed-loop manipulation strategies through an inversion of the discrete dynamics that reduce the many-input, three-output distributed control problem to a standard three-input, three-output control problem that operates under distributed control. In effect, the array of actuators is reduced to a single virtual actuator capable of applying a desired net force and moment on an object. It is proven that even in the presence of dynamic coupling and nonlinearities introduced due to discreteness, these closed-loop strategies are asymptotically stable. Multimedia extensions include a complete simulator and videos of the experimental prototype.