Chao Daihong

Design of a 6-DOF compliant manipulator based on serial-parallel architecture

A novel dexterous 6DOF manipulator serially connected by two compliant parallel stages is presented in this paper. The upper stage is a 3-RPS mechanism and the lower one is a 3-RRR mechanism. In virtue of the method of the physical model of the solution space, optimal design of the lower stage has been accomplished. Then, the calibration of the lower stage is undergoing by means of an ultra-precision vision system. The experiment shows that the lower stage possesses workspace of 120 mum times 130 mum times 18mrad with the resolution of 50 nm, 50 nm, 18 arcsec, respectively. This manipulator is to be used as a fiber optics aligner

Manufacturing error analysis of compliant 3-DOF microrobot

In the fields of micro/nanopositioning application, error analysis is an effective way to enhance the precision of micromanipulators. Manufacturing imperfections, which are inevitable, are the most important factors influencing the accuracy. Therefore, various manufacturing imperfections were studied by taking a planar 3 degrees of freedom (3-DOF) flexure hinge-based microrobot as a case. By formulating static stiffness of the robot, mapping between manufacturing imperfections and end-effector positioning accuracy was obtained. Using the theoretical calculation and finite element method (FEM), effects of various machining imperfection types on end-effector positioning accuracy were evaluated. The results showed that errors of the radium of the hinges and angular differences of the centerline of the hinges were dominant factors resulting in output errors. Conclusions drawn from the experiments can be used to instruct the design of compliant parallel mechanisms by distributing various manufacturing differences of configurable parameters to guarantee precision in the positioning of the end-effector within the required range; they may also be helpful while calibrating this kind of manipulator.