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The isotropy is one of the important performance indexes of the six-axis acceleration sensing mechanism, which determines the measurement accuracy of the sensor. In order to obtain the complete isotropy of the sensing mechanism, a new configuration synthesis method is proposed. Firstly, based on the Newton-Euler method and the inherent scale constraint relationship between the branches, the forward decoupling equation of the Stewart-type six-axis acceleration sensing mechanism is constructed. Secondly, the relationship between the isotropy of the sensing mechanism and the condition number of the input matrix in the forward decoupling equation is analyzed, and the mapping relationship between the branch pose and the input matrix is analyzed. Then, the configuration synthesis steps of the fully isotropic sensing mechanism are created. Finally, following this step, a "12-6" Stewart-type six-axis acceleration sensing mechanism is synthesized and a virtual experiment is carried out. The two cases of adding 0.100% random disturbance and zero disturbance are compared, and the results show that the maximum reference error of six-dimensional acceleration is 0.169%, that is, the magnification of the input and output errors is only 1.69. This shows that the new configuration has excellent isotropic properties. [ABSTRACT FROM AUTHOR]

Topological reconfiguration can improve the static stiffness and fault tolerance of parallel robots, but the problem of whether the robot can reach any specified pose without singular configuration has not been solved. Therefore, this paper takes the reconfigurable 3-RRR planar parallel robot as the research object, and proposes a path planning method that can realize “ point-to-point ” tracking. Firstly, the inverse kinematics model before reconfiguration is established, and six paths based on topological reconfiguration are found. Then, a “ four-step ” planning algorithm is constructed, which is suitable for “ point-to-point ” path tracking of reconfigurable parallel robots with any degree of freedom. It has intuitive geometric interpretation and can eliminate all singularities. The effectiveness of the planning algorithm is verified by an example. Further, based on the screw theory, the input and output transfer indexes under each input mode are calculated, and the optimal solution of the input mode is obtained by using the local transfer index. Finally, the “ point-topoint ” path planning algorithm is extended to continuous path planning. [ABSTRACT FROM AUTHOR]

A new type of variable cell kinematic pair is designed, which can be used to realize the reconstruction of 3-revolute‑joint, revolute‑joint, revolute‑joint (RRR) planar parallel mechanism. The kinematic models of R-R-R and revolute‑joint, prismatic‑joint, revolute‑joint (R-P-R) modes are derived and verified, including forward and inverse solutions, which can be used to calculate the singular configuration and workspace of parallel mechanism.The research results show that the designed variable cell kinematic pair can realize the reconfiguration function of the mechanism. The forward kinematics algorithms in the two modes are consistent, both of which are unary eighth-order equations. The inverse kinematics solution of R-RR type is three quadratic equations, and the inverse kinematics solution of R-P-R type can be expressed directly by the distance formula between two points. Finally, the correctness of the kinematic model is verified by the virtual prototype experiment. [ABSTRACT FROM AUTHOR]

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Based on the traditional three degree of freedom (DOF) planar parallel mechanism, a novel reconfigurable 3-DOF planar parallel mechanism is proposed. Firstly, based on the theory and method of topology design of the parallel mechanism position and orientation characteristic (POC). The switch between the 3-revolute-joint, prismatic-joint, revolute-joint (3-RPR) and 3-revolute-joint, revolute-joint, revolute-joint (3-RRR) planar parallel mechanisms is realized through a reconfigurable branch chain. Then, taking 3-RRR configuration as an example, the important topological indexes of the mechanism, such as POC, DOF and coupling degree, are analyzed. Based on the structural characteristics and geometric constraints of the mechanism, the inverse kinematics model is derived by using the closed vector method. Finally, the position workspace of the mechanism is analyzed based on the geometric constraint method of the branched chain and the inverse solution model respectively. This work provides not only a new idea for the analysis of mechanism workspace, but also a new choice for the design of mechanism. [ABSTRACT FROM AUTHOR]

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A new type of 3-DOF parallel mechanism with analytical position forward solution is proposed by the author, and its reverse dynamic equation is solved. Different from t he traditional dynamic paper using inverse kinematics, the displacement, velocity and acceleration equations of the mechanism are established and solved by forward kinematic analysis. T he inverse dynamic equation of t he mechanism is constructed and solved by analyzing the force on each member and based on Newton-Euifler method. Through Matlab example and ADAMS simulation, the inverse dynamics is verified by an example. The maximum driving force error of each moving pair is 1.32%, 5.8% and 5.2% respectively. This paper provides a theoretical basis for the design, manufacture and application of the mechamsm. [ABSTRACT FROM AUTHOR]

Using appropriate and effective strategies to attract, train and retain young librarians is the key to maintaining the core competitiveness of academic libraries. In order t o build a high-quality young librarian team, Shanghai Jiao Tong University Library has made systematic explorations on recruitment, job appointment, salary management, job promotion, professional training, international exchanges and librarians' assessment over the past t e n years, and look forward to the future development of young librarians in university libraries during the "14th Five-Year Plan" period. [ABSTRACT FROM AUTHOR]

With the development of parallel robot technology，the necessity of studying the workspace and singularity of parallel robot is presented to improve the motion performance. The research status and characteristics of workspace and singularity at home and abroad are described in detail based on different research methods. Furthermore，individual innovative ideas and common problems for different research methods of workspace and singularity are pointed out. Through deeply analyzing the principle of research methods，the breakthrough is found to solve common problems. Meanwhile，the remaining problems in research are analyzed. Combining with the future development trend，breakthroughs in structural synthesis and theoretical innovation can provide strong impetus for the development of parallel robot. The conclusions and prospects provide valuable references for researchers engaged in this field. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)