Individuals with hemiplegia suffer from impaired arm movements that appear as a marked change in arm stiffness. A quantitative measure of arm stiffness would characterize rehabilitation therapy effectively, while litt...Individuals with hemiplegia suffer from impaired arm movements that appear as a marked change in arm stiffness. A quantitative measure of arm stiffness would characterize rehabilitation therapy effectively, while little mechanism is designed to implement the function. A symmetrical five-bar linkage consisting of two revolute joints and three prismatic joints is presented. Inverse kinematics and forward kinematics are obtained first. Then inverse singularities and direct singularities of the mechanism are gained. The global stiffness index is defined based on the results of kinematics analysis. Finally, optimal dimensional synthesis of the mechanism in terms of maximum stiffness is conducted by genetic algorithms. The calculation results show that with the length of both the two linkage a=830 mm, the interacting angle of the two guides 2δ=4.48 radian, and the maximum range of displacement of the two carriers dmax=940 mm, the mechanism achieves highest rigidity and its workspace is singularity-free, which covers the human left and right arm range of motion. The proposed novel mechanism featuring high rigidity and a singularity-free workspace can provide rehabilitation training, also solve the problem of quantitative measure of arm stiffness.展开更多
COBOT is a new kind of collaborative robot , which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based t...COBOT is a new kind of collaborative robot , which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based the feature of nonhlonnmic constraint. The dynamic model of differential mechanism and five-bar architecture COBOT is founded. There are two kinds of coupled mode of two CVT:serial and parallel. In this paper, we present the dynamic model of serial and parallel COBOT take five-bar COBOT as research object. From the dynamic analysis foregoing, both serial and parallel COBOT model are have the feature of nonholonomic constraint. The ending track and moving state are controlled by the force of control motor and operator. The control motor can not control the movement and ending track of COBOT without the cooperation of operator.展开更多
For a spherical four-bar linkage,the maximum number of the spherical RR dyad(R:revolute joint)of five-orientation motion generation can be at most 6.However,complete real solution of this problem has seldom been st...For a spherical four-bar linkage,the maximum number of the spherical RR dyad(R:revolute joint)of five-orientation motion generation can be at most 6.However,complete real solution of this problem has seldom been studied.In order to obtain six real RR dyads,based on Strum's theorem,the relationships between the design parameters are derived from a 6th-degree univariate polynomial equation that is deduced from the constraint equations of the spherical RR dyad by using Dixon resultant method.Moreover,the Grashof condition and the circuit defect condition are taken into account.Given the relationships between the design parameters and the aforementioned two conditions,two objective functions are constructed and optimized by the adaptive genetic algorithm(AGA).Two examples with six real spherical RR dyads are obtained by optimization,and the results verify the feasibility of the proposed method.The paper provides a method to synthesize the complete real solution of the five-orientation motion generation,which is also applicable to the problem that deduces to a univariate polynomial equation and requires the generation of as many as real roots.展开更多
With the use of mechanical system dynamics simulation analysis software ADAMS,the virtual prototype model of Closed Five-bow-shaped-bar Linkage was established.The dynamic of the mechanism was analyzed,and providing t...With the use of mechanical system dynamics simulation analysis software ADAMS,the virtual prototype model of Closed Five-bow-shaped-bar Linkage was established.The dynamic of the mechanism was analyzed,and providing the theoretical basis for selection of parameter of electric machine of driving joint and accurate control of dynamics.展开更多
The relationship between the stability and the configuration of the driving joint was studied as a measure to improve the stability of robot.The Lagrange dynamic equation of the robot was established.According to the ...The relationship between the stability and the configuration of the driving joint was studied as a measure to improve the stability of robot.The Lagrange dynamic equation of the robot was established.According to the principle of virtual work,the least squares solution of each joint torque was obtained.The relationship between the stability of the robot and the configuration of the driving joint is obtained by the sum of the norms of the joint torque.Finally,numerical simulations verify the correctness of the theory.展开更多
The concept of virtual slider crank mechanism is proposed and decoupled to obtain parameters of controllable five bar mechanism without any principle error for any given trajectory. The model is simple and easy to sol...The concept of virtual slider crank mechanism is proposed and decoupled to obtain parameters of controllable five bar mechanism without any principle error for any given trajectory. The model is simple and easy to solve. This method has no convergence,flexible workspace and singularity of the mechanism problem. Through this method,we don’ t need any curve to fit the trajectory point. Using MATLAB program to calculate,the computation time can be reduced to less than 3% of the original. Finally,an example is given to illustrate the method which is meanwhile compared with the traditional five bar design method.展开更多
基金Supported by National Natural Science Foundation of China(Grant No U1304510)Development Foundation for Outstanding Young Teachers of Zhengzhou University,China(Grant No.1421321076)
文摘Individuals with hemiplegia suffer from impaired arm movements that appear as a marked change in arm stiffness. A quantitative measure of arm stiffness would characterize rehabilitation therapy effectively, while little mechanism is designed to implement the function. A symmetrical five-bar linkage consisting of two revolute joints and three prismatic joints is presented. Inverse kinematics and forward kinematics are obtained first. Then inverse singularities and direct singularities of the mechanism are gained. The global stiffness index is defined based on the results of kinematics analysis. Finally, optimal dimensional synthesis of the mechanism in terms of maximum stiffness is conducted by genetic algorithms. The calculation results show that with the length of both the two linkage a=830 mm, the interacting angle of the two guides 2δ=4.48 radian, and the maximum range of displacement of the two carriers dmax=940 mm, the mechanism achieves highest rigidity and its workspace is singularity-free, which covers the human left and right arm range of motion. The proposed novel mechanism featuring high rigidity and a singularity-free workspace can provide rehabilitation training, also solve the problem of quantitative measure of arm stiffness.
基金the National Natural Science Foundation of China( 60275030) Harbin Science and Technology Bureau(2002AFLXJ004)
文摘COBOT is a new kind of collaborative robot , which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based the feature of nonhlonnmic constraint. The dynamic model of differential mechanism and five-bar architecture COBOT is founded. There are two kinds of coupled mode of two CVT:serial and parallel. In this paper, we present the dynamic model of serial and parallel COBOT take five-bar COBOT as research object. From the dynamic analysis foregoing, both serial and parallel COBOT model are have the feature of nonholonomic constraint. The ending track and moving state are controlled by the force of control motor and operator. The control motor can not control the movement and ending track of COBOT without the cooperation of operator.
基金Supported by National Natural Science Foundation of China(Grant Nos.51375059,61105103)National Hi-tech Research and Development Program of China(863 Program,Grant No.2011AA040203)Beijing Municipal Natural Science Foundation of China(Grant No.4132032)
文摘For a spherical four-bar linkage,the maximum number of the spherical RR dyad(R:revolute joint)of five-orientation motion generation can be at most 6.However,complete real solution of this problem has seldom been studied.In order to obtain six real RR dyads,based on Strum's theorem,the relationships between the design parameters are derived from a 6th-degree univariate polynomial equation that is deduced from the constraint equations of the spherical RR dyad by using Dixon resultant method.Moreover,the Grashof condition and the circuit defect condition are taken into account.Given the relationships between the design parameters and the aforementioned two conditions,two objective functions are constructed and optimized by the adaptive genetic algorithm(AGA).Two examples with six real spherical RR dyads are obtained by optimization,and the results verify the feasibility of the proposed method.The paper provides a method to synthesize the complete real solution of the five-orientation motion generation,which is also applicable to the problem that deduces to a univariate polynomial equation and requires the generation of as many as real roots.
文摘With the use of mechanical system dynamics simulation analysis software ADAMS,the virtual prototype model of Closed Five-bow-shaped-bar Linkage was established.The dynamic of the mechanism was analyzed,and providing the theoretical basis for selection of parameter of electric machine of driving joint and accurate control of dynamics.
文摘The relationship between the stability and the configuration of the driving joint was studied as a measure to improve the stability of robot.The Lagrange dynamic equation of the robot was established.According to the principle of virtual work,the least squares solution of each joint torque was obtained.The relationship between the stability of the robot and the configuration of the driving joint is obtained by the sum of the norms of the joint torque.Finally,numerical simulations verify the correctness of the theory.
基金supported by National Innovation Training Project(201710959044)Anhui Province Quality Engineering Project(2016jyxm0336)Anhui Province Educational Department University Natural Science Research Project(KJ2017A523)
文摘The concept of virtual slider crank mechanism is proposed and decoupled to obtain parameters of controllable five bar mechanism without any principle error for any given trajectory. The model is simple and easy to solve. This method has no convergence,flexible workspace and singularity of the mechanism problem. Through this method,we don’ t need any curve to fit the trajectory point. Using MATLAB program to calculate,the computation time can be reduced to less than 3% of the original. Finally,an example is given to illustrate the method which is meanwhile compared with the traditional five bar design method.