The dynamic modeling and solution of the 3-■RS spatial parallel manipulators with flexible links were investigated.Firstly,a new model of spatial flexible beam element was proposed,and the dynamic equations of elements and branches of the parallel manipulator were derived.Secondly,according to the kinematic coupling relationship between the moving platform and flexible links,the kinematic constraints of the flexible parallel manipulator were proposed.Thirdly,using the kinematic constraint equations and dynamic model of the moving platform,the overall system dynamic equations of the parallel manipulator were obtained by assembling the dynamic equations of branches.Furthermore,a few commonly used effective solutions of second-order differential equation system with variable coefficients were discussed.Newmark numerical method was used to solve the dynamic equations of the flexible parallel manipulator.Finally,the dynamic responses of the moving platform and driving torques of the 3-■RS parallel mechanism with flexible links were analyzed through numerical simulation.The results provide important information for analysis of dynamic performance,dynamics optimization design,dynamic simulation and control of the 3-■RS flexible parallel manipulator.
With the development of network and the World Wide Web (WWW), the Internet has been growing and changing dramatically. More and more on-line database systems and different kinds of services are available for astronomy research. How to help users find their way through the jungle of information services becomes an important challenge. Although astronomers have been aware of the importance of interoperability and introduced the concept of Virtual Observatory as a uniform environment for future astronomical on-line resources and services, transparent access to heterogeneous on-line information is still difficult. SkyMouse is a lightweight interface for distributed astronomical on-line resources and services, which is designed and developed by us, i.e., Chinese Virtual Observatory project. Taking advantage of screen word-capturing technology, different kinds of information systems can be queried through simple mouse actions, and results are returned in a uniform web page. SkyMouse is an easy to use application, aiming to show basic information or to create a comprehensive overview of a specific astronomical object. In this paper current status of on-line resources and services access is reviewed; system architecture, features and functions of SkyMouse are described; challenges for intelligent in-terface for on-line astronomical resources and services are discussed.
CUI ChenZhouSUN HuaPingZHAO YongHengLUO YuQI DaZhi
