摘要：The singular points of a 6-SPS Stewart platform are distributed on the multi-dimensional singularity hypersurface in the task-space, which divides the workspace of the manipulator into several singularity-free regions. Because of the motion un- certainty at singular points, while the manipulator traverses this kind of hypersurface from one singularity-free region to another, its motion cannot be predetermined. In this paper, a detailed approach for the manipulator to traverse the singularity hypersurface with its non-persistent configuration is presented. First, the singular point transfer disturbance and the pose disturbance, which make the perturbed singular point transfer horizontally and vertically, respectively, are constructed. Through applying these disturbances into the input parameters within the maximum loss control domain, the perturbed persistent configuration is transformed into its corresponding non-persistent one. Under the action of the disturbances, the manipulator can traverse the singularity hypersurface from one singularity-flee region to another with a desired configuration.

摘要：parallel manipulators have many advantages over serial manipulators in termsof high load/weight ratio, velocity, stiffness and precision. A dimensional design theory andmethodology of six degrees of freedom scissor parallel manipulator (SPM) is investigated. The SPMkinematics inverse equation is given. Based on the formulation of the local dexterity and thedefinition about the indexes of workspace incircle radius, the effects of the design parameters onthe dexterity and workspace are discussed. Moreover the incircle radius change ratio about workspaceare defined and used as the evaluated indicator to analyze the effects of the design parameters onthe performances. A dimensional design theory that could satisfy the requirement of dexterity andworkspace is proposed. The dimensional design theory and methodology can be of help in the design,trajectory planning and control of parallel manipulator.

摘要：Configuration design is an essential, creative and decision-making step m parallel manipulator design process, in which modeling and assembly are iterative and trivial. Combined approach with automatic parametric modeling and automatic assembly is proposed for parallel manipulator configuration design. The design process and key techniques, such as configuration design, configuration verification, poses calculation of all parts in parallel manipulator, virtual assembly and etc., are discussed and demonstrated by an example. A software package is developed for parallel manipulator configuration design based on the proposed method with Visual C＋＋ and UG/OPEN on Unigraphics.

摘要：This paper addresses geometry design of a new kind of 2-DOF parallel manipulator actuated horizontally by linear actua- tors. The first step of the optimum design involves developing a non-dimensional structure of the planar 2-DOF parallel manipulator. The global conditioning index, global velocity index, global stiffness index and global payload index of the 2-DOF parallel manipu- lators are investigated, and the geometrical parameters without dimension are determined with respect to the specification on per- formances. Finally, based on the optimum non-dimensional result, the optimum dimensional parameters are achieved which is suit- able for the desired workspace. The optimum methodology of this paper is convenient and can be extended to other parallel mecha-

摘要：A safety mechanism capable of moving at will within the range of its whole link lengths is designed based on the link space. Sixteen extreme poses are obtained in a Stewart platform. The singular points of the extreme poses are solved by using homotopy method as well as the judgment condition of singular points, and thereby the maximum link lengths are achieved. The rotation angles of joints and the distances between two neighboring links are analyzed in a calculation example in which that the mechanism moves among the extreme poses is assumed. Then an algorithm to test the safety mechanism is presented taking the constraint conditions into account. A safety mechanism having optimal properties of global movement is worked out by optimizing all structural parameters through minimizing the average condition number of extreme poses.

摘要：Every year more than 5 million people worldwide become hemiplegic as a direct consequence of stroke. This neurological deficiency, often leads to a partial or a total loss of standing up abilities and/or ambulation skills. In order to propose new supporting solutions lying between the wheelchair and the walker, this paper presents a technological strategy for designing an assistive device for a biomechanical study of the Sit-To-Stand movement （STS）. The control algorithms are implemented in TwinCAT runtime environment. The communi- cation between the component and the control computer is ensured via the EtherCAT fieldbus. The aim of this architecture lies in the fact that it allows a quick development of a research prototype with the same safety issues found on an industrial machine. An experimental test of the STS strategy is presented and discussed in order to evaluate the strategy.

摘要：This is a brief summary of a paper presented at the 5th Japan-China Joint Conference on Graphics Education in Osaka 2001.