An adaptive control scheme for robot manipulators

An adaptive control scheme is developed for a robot manipulator to track a desired trajectory as closely as possible in spite of a wide range of manipulator motions and parameter uncertainties of links and payload.

The presented control scheme has two components: a nominal control and a variational control. The nominal control, generated from direct calculation of the manipulator dynamics along a desired trajectory, drives the manipulator to a neighbourhood of the trajectory. Then a new adaptive regulation scheme is devised based on the Lyapunov direct method, which generates the variational control that regulates the perturbation in the vicinity of the desired trajectory.     

Decentralized adaptive control scheme for control of a multi-arm-type robot

This paper deals with the problem of decentralized stabilization for a class of unknown large-scale dynamic systems formed of interconnected subsystems under constant disturbances. A decentralized adaptive control scheme is proposed based on the Lyapunov direct method and a condition of asymptotic stability is derived. Then the decentralized adaptive control scheme is applied for a class of robot manipulators to track the desired trajectory as closely as possible despite a wide range of manipulator motions and parameter uncertainties of links and payload.     

Development of Ubiquitous Simulation Service Structure Based on High Performance Computing Technologies

The simulation field became essential in designing or developing new casting products and in improving manufacturing processes within limited time, because it can help us to simulate the nature of processing, so that developers can make ideal casting designs. To take the prior occupation at commercial simulation market, so many development groups in the world are doing their every effort. They already reported successful stories in manufacturing fields by developing and providing the high performance simulation technologies for multipurpose. But they all run at powerful desk-side computers by well-trained experts mainly, so that it is hard to diffuse the scientific designing concept to newcomers in casting field. To overcome upcoming problems in scientific casting designs, we utilized information technologies and full-matured hardware backbones to spread out the effective and scientific casting design mind, and they all were integrated into Simulation Portal on the web. It professes scientific casting design on the NET including ubiquitous access way represented by ＂Anyone, Anytime, Anywhere＂ concept for casting designs.     

土工离心机模拟泥石流问题的相似性考虑

尺度效应是阻碍对泥石流复杂动力学过程理解的最主要因素。土工离心机通过提供一个等效的高倍重力加速度场,能够在模型中还原岩土工程原型的应力状态,为泥石流物理模拟的尺度效应难题提供了一个经济可行的解决方案。在总结前人提出的两相流（泥石流）无量纲参数的基础上,建立了应用于土工离心机模拟泥石流的分层次相似性试验设计体系,可以确保模型和原型中泥石流运动学与动力学参数绝对值和相对值的一致,从而可以系统性地还原泥石流原型问题的物理过程。同时,针对对模拟结果产生较大影响的科里奥利效应和1g自然重力加速度,建议试验设计阶段选择有效旋转半径更大的离心机并适当降低旋转角速度。研究结果对泥石流和碎屑流的小尺度、大尺度物理模拟以及离心机模拟具有理论和技术层面的参考意义。     

Gauche conformation of acyclic guest molecules appearing in the large cages of structure-H clathrate hydrates

In the present study, measurements and analyses were made of the High-Power Decoupling (HPDEC) solid-state ¹³C NMR spectra of structure-H (sH) methane hydrates with isopentane, one of the simplest and smallest acyclic large guest molecules, and methylcyclohexane (MCH), a commonly used cyclic guest molecule that is larger than isopentane. From the spectroscopic information, clear and definite evidence for the molecular conformation of acyclic guest molecules that are sufficiently small so as to be entrapped into the structure-H large cage (sH-L) was expected. The ¹³C NMR chemical shift change was additionally checked through the use of a hydrogen-hydrogen steric perturbation model. From the overall results, we concluded that one of the smallest acyclic guest molecules, isopentane, participating in the formation of a structure-H clathrate hydrate is encaged, confirming the gauche conformation in large cavities. The present results strongly suggest that the guest position and structure in hydrate cages are greatly influenced by both short-range interactions between guest molecules and cage frameworks and long-range interactions between small and large guests. Accordingly, cage dynamics must be carefully considered when a specific sH hydrate is designed and synthesized for the purpose of tuning material properties.     

Multi-national capital budgeting using chance-constrained goal programming

A chance-constrained goal programming model is developed for the direct foreign investment decisions of U.S.-based multi-national companies. Goals, objectives and constraints, which are unique to direct foreign investment decisions, are included in the model. The model also considers economic exposure of exchange-rate risk. A solution procedure is suggested. The model is illustrated by a numerical example that includes sensitivity analysis.