The object of study is about dynamic modeling and control for a 2degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic anddynamic equations are established according to the characte...The object of study is about dynamic modeling and control for a 2degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic anddynamic equations are established according to the characteristics of mixed rigid and flexiblestructure. By using the singular perturbation approach (SPA), the model of the mechanism can beseparated into slow and fast subsystems. Based on the feedback linearization theory and inputshaping technique, the large scale rigid motion controller and the flexible link vibrationcontroller can be designed separately to achieve fast and accurate positioning of the PM.展开更多
The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of be...The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of beam element is derived based on finite element method. The kinematic constraints of parallel manipulator with rigid and flexible links are obtained by analyzing the motive parameters of moving platform and the relationships of movements of kinematic chains, and the overall kinetic equation of the parallel mechanism with rigid and flexible links is derived by assembling the differential equations of motion of components. On the basis of abovementioned analyses, the dynamic mechanical analysis of the spatial parallel manipulator with rigid and flexible links is conducted. After obtaining the method for force analysis and expressions for the calculation of dynamic stress of flexible components, the dynamic analysis and simulation of spatial parallel manipulator with rigid and flexible links is performed. The result shows that because of the elastic deformation of flexible components in the parallel mechanism with rigid and flexible links, the force on each component in the mechanism fluctuates sharply, and the change of normal stress at the root of drive components is also remarkable. This study provides references for further studies on the dynamic characteristics of parallel mechanisms with rigid and flexible links and for the optimization of the design of the mechanism.展开更多
A 3D model of the spatial four-bar weft insertion mechanism was built with unigraphics NX(UG) according to the actual requirement,and dynamics simulation was carried out by importing the model into ADAMS.Without consi...A 3D model of the spatial four-bar weft insertion mechanism was built with unigraphics NX(UG) according to the actual requirement,and dynamics simulation was carried out by importing the model into ADAMS.Without considering the clearance,the motion characteristic curve of the sword belt was generated through ADAMS combined with MATLAB.In this paper the hinge between the rod and the sector gear was selected as an example with different values of clearance,outputting the motion characteristic curve of the sword belt.Finite element analysis(FEA)was conducted,the flexible body was generated by importing the forked frame into ANSYS,and flexible dynamics simulation was carried out by importing the flexible body into ADAMS to replace the rigid rod.A comprehensive comparison of the output characteristics of the sword belt was conducted in the consideration of the clearance or flexible.Analysis of the force on the left hinge of the rod was carried out with the ADAMS post processing module.With the same clearance,considering the flexibility,amplitude of fluctuation of the force on the hinge increased obviously.展开更多
The conventional beam pumping unh consumes a large amount of energy due to its unsmooth movement. In this work, we design a new energy-saving parallel four-bar pumping unit and derive the kinematic and dynamic law of ...The conventional beam pumping unh consumes a large amount of energy due to its unsmooth movement. In this work, we design a new energy-saving parallel four-bar pumping unit and derive the kinematic and dynamic law of the drive mechanism systematically by theoretical method. For the given target technical parameter, the theoretical results are verified by computer simulation, which shows that the simulation dynamic curves agree well with the theoretical ones and the calculated power consumption is low. Theoretical analysis shows that the newly designed pumping unit reduces average power by 28.8% compared with its conventional counterpart. The much lower theoretical energy consumption and the better dynamic performance indicate that the new energy-saving pumping unit is well designed and will have a significant application prospect.展开更多
A prototype of a novel hybrid hand is developed by combing a parallel wrist with three flexible fingers.Its dynamics model is established,its grabbed forces are measured,and its grabbing performances are analyzed.Firs...A prototype of a novel hybrid hand is developed by combing a parallel wrist with three flexible fingers.Its dynamics model is established,its grabbed forces are measured,and its grabbing performances are analyzed.First,Jacobian and Hessian matrices of the moving platform in the parallel wrist are derived,the kinematics formulas for solving the general velocity and the general acceleration of the moving platform are derived.Second its dynamics model is established for solving the dynamic actuation forces,the dynamic constrained forces of the developed hybrid hand.Third,its simulation mechanism is constructed in Matlab,and the theoretical solutions of the kinematics and the dynamics of the developed hybrid hand are verified to be correct using its simulation mechanism.Finally,when objects with different mass are grabbed by prototype of hybrid hand in different poses,the grabbed forces are measured,and the grabbing performances are discovered and analyzed to verify its merits.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50390064, No.50375099) Doctorate Foundation of Ministry of Education of China(No.20020248048).
文摘The object of study is about dynamic modeling and control for a 2degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic anddynamic equations are established according to the characteristics of mixed rigid and flexiblestructure. By using the singular perturbation approach (SPA), the model of the mechanism can beseparated into slow and fast subsystems. Based on the feedback linearization theory and inputshaping technique, the large scale rigid motion controller and the flexible link vibrationcontroller can be designed separately to achieve fast and accurate positioning of the PM.
基金Projects(2014QNB18,2015XKMS022)supported by the Fundamental Research Funds for the Central Universities of ChinaProjects(51475456,51575511)supported by the National Natural Science Foundation of China+1 种基金Project supported by the Priority Academic Programme Development of Jiangsu Higher Education InstitutionsProject supported by the Visiting Scholar Foundation of China Scholarship Council
文摘The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of beam element is derived based on finite element method. The kinematic constraints of parallel manipulator with rigid and flexible links are obtained by analyzing the motive parameters of moving platform and the relationships of movements of kinematic chains, and the overall kinetic equation of the parallel mechanism with rigid and flexible links is derived by assembling the differential equations of motion of components. On the basis of abovementioned analyses, the dynamic mechanical analysis of the spatial parallel manipulator with rigid and flexible links is conducted. After obtaining the method for force analysis and expressions for the calculation of dynamic stress of flexible components, the dynamic analysis and simulation of spatial parallel manipulator with rigid and flexible links is performed. The result shows that because of the elastic deformation of flexible components in the parallel mechanism with rigid and flexible links, the force on each component in the mechanism fluctuates sharply, and the change of normal stress at the root of drive components is also remarkable. This study provides references for further studies on the dynamic characteristics of parallel mechanisms with rigid and flexible links and for the optimization of the design of the mechanism.
基金National Natural Science Foundation of China(No.51175475)Natural Science Foundation of Zhejiang Province,China(No.LY14E050027)
文摘A 3D model of the spatial four-bar weft insertion mechanism was built with unigraphics NX(UG) according to the actual requirement,and dynamics simulation was carried out by importing the model into ADAMS.Without considering the clearance,the motion characteristic curve of the sword belt was generated through ADAMS combined with MATLAB.In this paper the hinge between the rod and the sector gear was selected as an example with different values of clearance,outputting the motion characteristic curve of the sword belt.Finite element analysis(FEA)was conducted,the flexible body was generated by importing the forked frame into ANSYS,and flexible dynamics simulation was carried out by importing the flexible body into ADAMS to replace the rigid rod.A comprehensive comparison of the output characteristics of the sword belt was conducted in the consideration of the clearance or flexible.Analysis of the force on the left hinge of the rod was carried out with the ADAMS post processing module.With the same clearance,considering the flexibility,amplitude of fluctuation of the force on the hinge increased obviously.
基金Supported by the Ministry of Science and Technology Innovation Fund for SMEs (09C26214204812)the Venture Capital Fund for SMEs (09C26154204991)
文摘The conventional beam pumping unh consumes a large amount of energy due to its unsmooth movement. In this work, we design a new energy-saving parallel four-bar pumping unit and derive the kinematic and dynamic law of the drive mechanism systematically by theoretical method. For the given target technical parameter, the theoretical results are verified by computer simulation, which shows that the simulation dynamic curves agree well with the theoretical ones and the calculated power consumption is low. Theoretical analysis shows that the newly designed pumping unit reduces average power by 28.8% compared with its conventional counterpart. The much lower theoretical energy consumption and the better dynamic performance indicate that the new energy-saving pumping unit is well designed and will have a significant application prospect.
基金This study was funded by MajorResearch Project of National Natural ScienceFoundationof China(Grant number 91748125)Natural Science Foundation of Hebei,China(Grant number E2020203010).
文摘A prototype of a novel hybrid hand is developed by combing a parallel wrist with three flexible fingers.Its dynamics model is established,its grabbed forces are measured,and its grabbing performances are analyzed.First,Jacobian and Hessian matrices of the moving platform in the parallel wrist are derived,the kinematics formulas for solving the general velocity and the general acceleration of the moving platform are derived.Second its dynamics model is established for solving the dynamic actuation forces,the dynamic constrained forces of the developed hybrid hand.Third,its simulation mechanism is constructed in Matlab,and the theoretical solutions of the kinematics and the dynamics of the developed hybrid hand are verified to be correct using its simulation mechanism.Finally,when objects with different mass are grabbed by prototype of hybrid hand in different poses,the grabbed forces are measured,and the grabbing performances are discovered and analyzed to verify its merits.
