This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as subchains.The planar five-bar metamorphic linkages that have three phases resulting from locking of motors are c...This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as subchains.The planar five-bar metamorphic linkages that have three phases resulting from locking of motors are considered.Under the assumption that the constraint exerted by the reconfigurable limb can switch between no constraint,a constraint force,and a constraint couple,the output motions of the metamorphic linkage in its two planar four-bar linkage phases are identified.By adding an appropriate joint to planar four-bar linkages with translational output,four planar five-bar linkages that can be employed in the construction of reconfigurable limbs are enumerated.Serial chains that can provide a constraint couple and a constraint force are synthesized based on screw theory.Reconfigurable limbs that have three configurations associated with the three distinct phases of the metamorphic linkages are assembled with planar five-bar metamorphic linkages and serial chains with four degrees of freedom.A class of reconfigurable parallel mechanisms are constructed by connecting a moving platform and a base with three identical reconfigurable limbs.The degrees of freedom of the reconfigurable parallel mechanism in different configurations with the metamorphic linkages in different phases are given.Finally,the actuation scheme for this kind of mechanisms is addressed.展开更多
A method for improving dynamic characteristics of planar linkages by activelyvarying the speed function of the input link is presented. Design criteria and constraints for thedynamic design of variable speed planar li...A method for improving dynamic characteristics of planar linkages by activelyvarying the speed function of the input link is presented. Design criteria and constraints for thedynamic design of variable speed planar linkages are developed. Both analytical and optimizationapproaches for determining suitable input speed functions to minimize the driving torque, theshaking moment, or both simultaneously of planar linkages, subject to various design requirementsand constraints, are derived. Finally, some examples are given to illustrate the design procedureand to verify its feasibility.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51075025,51175029)Beijing Natural Science Foundation of China(Grant No.3132019)the Program for New Century Excellent Talents in University of China(Grant No.NCET-12-0769)
文摘This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as subchains.The planar five-bar metamorphic linkages that have three phases resulting from locking of motors are considered.Under the assumption that the constraint exerted by the reconfigurable limb can switch between no constraint,a constraint force,and a constraint couple,the output motions of the metamorphic linkage in its two planar four-bar linkage phases are identified.By adding an appropriate joint to planar four-bar linkages with translational output,four planar five-bar linkages that can be employed in the construction of reconfigurable limbs are enumerated.Serial chains that can provide a constraint couple and a constraint force are synthesized based on screw theory.Reconfigurable limbs that have three configurations associated with the three distinct phases of the metamorphic linkages are assembled with planar five-bar metamorphic linkages and serial chains with four degrees of freedom.A class of reconfigurable parallel mechanisms are constructed by connecting a moving platform and a base with three identical reconfigurable limbs.The degrees of freedom of the reconfigurable parallel mechanism in different configurations with the metamorphic linkages in different phases are given.Finally,the actuation scheme for this kind of mechanisms is addressed.
基金This project is supported by National Natural Science Foundation of China(No.50405004, No.50335040).
文摘A method for improving dynamic characteristics of planar linkages by activelyvarying the speed function of the input link is presented. Design criteria and constraints for thedynamic design of variable speed planar linkages are developed. Both analytical and optimizationapproaches for determining suitable input speed functions to minimize the driving torque, theshaking moment, or both simultaneously of planar linkages, subject to various design requirementsand constraints, are derived. Finally, some examples are given to illustrate the design procedureand to verify its feasibility.
