scholarly journals Kinematics Performance and Dynamics Analysis of a Novel Parallel Perfusion Manipulator with Passive Link

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Hui Yang ◽  
Hairong Fang ◽  
Yuefa Fang ◽  
Haibo Qu

In order to solve the problem of the honeycombs perfusion in the thermal protection system of the spacecraft, this paper presents a novel parallel perfusion manipulator with one translational and two rotational (1T2R) degrees of freedom (DOFs), which can be used to construct a 5-DOF hybrid perfusion system for the perfusion of the honeycombs. The proposed 3PSS&PU parallel perfusion manipulator is mainly utilized as the main body of the hybrid perfusion system. The inverse kinematics and the Jacobian matrix of the proposed parallel manipulator are obtained. The analysis of kinematics performance for the proposed parallel manipulator including workspace, singularity, dexterity, and stiffness is conducted. Based on the virtual work principle and the link Jacobian matrix, the dynamic model of the parallel perfusion manipulator is carried out. With reference to dynamic equations, the relationship between the driving force and the mechanism parameters can be derived. In order to verify the correctness of the kinematics and dynamics model, the comparison of theoretical and simulation curves of the motion parameters related to the driving sliders is performed. Corresponding analyses illustrate that the proposed parallel perfusion possesses good kinematics performance and could satisfy the perfusion requirements of the honeycombs. The correctness of the established kinematics and dynamics models is proved, which has great significance for the experimental research of the perfusion system.

Author(s):  
Richard Stamper ◽  
Lung-Wen Tsai

Abstract The dynamics of a parallel manipulator with three translational degrees of freedom are considered. Two models are developed to characterize the dynamics of the manipulator. The first is a traditional Lagrangian based model, and is presented to provide a basis of comparison for the second approach. The second model is based on a simplified Newton-Euler formulation. This method takes advantage of the kinematic structure of this type of parallel manipulator that allows the actuators to be mounted directly on the base. Accordingly, the dynamics of the manipulator is dominated by the mass of the moving platform, end-effector, and payload rather than the mass of the actuators. This paper suggests a new method to approach the dynamics of parallel manipulators that takes advantage of this characteristic. Using this method the forces that define the motion of moving platform are mapped to the actuators using the Jacobian matrix, allowing a simplified Newton-Euler approach to be applied. This second method offers the advantage of characterizing the dynamics of the manipulator nearly as well as the Lagrangian approach while being less computationally intensive. A numerical example is presented to illustrate the close agreement between the two models.


2015 ◽  
Vol 39 (3) ◽  
pp. 431-441 ◽  
Author(s):  
Yi-Chang Wu ◽  
Tze-Cheng Wu

This paper presents embodiment design of 5-speed rear drive hubs for bicycles. A 7-link, 2-degrees of freedom (DOF) compound planetary gear train as the main body of a rear drive hub is introduced. The relationship between the number of coaxial links of a planetary gear train and the number of gear stages that a drive hub can provide with is discussed. By means of kinematic analysis, four speed ratios of the planetary gear train are derived, which represents four forward gears of the rear drive hub. By adding a direct-drive gear, five forward gears can be provided and two feasible clutching sequence tables are synthesized. Manual translational-type gear-shifting mechanisms are further designed to incorporate with the planetary gear train for appropriately controlling the gear stage. The power-flow path at each gear stage is checked to verify the feasibility of the proposed design. Finally, two novel 5-speed bicycle rear drive hubs are presented.


2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Jun Wu ◽  
Binbin Zhang ◽  
Liping Wang

The paper deals with the evaluation of acceleration of redundant and nonredundant parallel manipulators. The dynamic model of three degrees-of-freedom (3DOF) parallel manipulator is derived by using the virtual work principle. Based on the dynamic model, a measure is proposed for the acceleration evaluation of the redundant parallel manipulator and its nonredundant counterpart. The measure is designed on the basis of the maximum acceleration of the mobile platform when one actuated joint force is unit and other actuated joint forces are less than or equal to a unit force. The measure for evaluation of acceleration can be used to evaluate the acceleration of both redundant parallel manipulators and nonredundant parallel manipulators. Furthermore, the acceleration of the 4-PSS-PU parallel manipulator and its nonredundant counterpart are compared.


2013 ◽  
Vol 373-375 ◽  
pp. 34-37
Author(s):  
Jian Xin Yang ◽  
Zhen Tao Liu ◽  
Jian Wei Sun

The dynamic modeling method for parallel robot based on the principle of virtual work and equivalent tree structure is proposed by taking off the platform and the chains as well as degenerating parallel robot into a tree structure, the closed-form solutions for the inverse and forward dynamics models of parallel robot are derived. The method is applied on kinematics and dynamics analysis of a representative 3-RRR spherical parallel robot.


Robotica ◽  
2011 ◽  
Vol 29 (6) ◽  
pp. 815-822 ◽  
Author(s):  
Bo Hu ◽  
Yi Lu

SUMMARYThe stiffness modeling and elastic deformation of 3 degrees of freedom, 3-universal joints–prismatic pairs–universal joints (UPU) parallel manipulator (PM) with one translation and two rotations are studied. First, the constraint wrenches are derived corresponding to the special orientation of universal joints in each of the UPU legs. Second, the elastic deformation of active legs produced by these active forces and constrained wrenches are derived. Third, a 6 × 6 Jacobian matrix is derived from constraint and active forces, and the statics is solved. Finally, the stiffness matrix of 3-UPU PM is established and its elastic deformation is solved.


2013 ◽  
Vol 198 ◽  
pp. 21-26
Author(s):  
Maciej Petko ◽  
Grzegorz Karpiel

The paper presents the process of development of a parallel manipulator for milling, and justifies why mechatronic approach can lead to successes. The resulting construction is a novel, versatile 3-RRPRR, fully-parallel manipulator with three translational degrees of freedom, characterizing in comparatively high payload capacity, large workspace and high attainable accelerations. The construction of the manipulator is shown, with analysis of its kinematics and dynamics. A controller is proposed, simulated and experimentally investigated. Finally, the conclusions and future works are presented.


Robotica ◽  
2015 ◽  
Vol 34 (9) ◽  
pp. 2056-2070 ◽  
Author(s):  
Po-Chih Lee ◽  
Jyh-Jone Lee

SUMMARYThis paper investigates the kinematics of one new isoconstrained parallel manipulator with Schoenflies motion. This new manipulator has four degrees of freedom and two identical limbs, each having the topology of Cylindrical–Revolute–Prismatic–Helical (C–R–P–H). The kinematic equations are derived in closed-form using matrix algebra. The Jacobian matrix is then established and the singularities of the robot are investigated. The reachable workspaces and condition number of the manipulator are further studied. From the kinematic analysis, it can be shown that the manipulator is simple not only for its construction but also for its control. It is hoped that the results of the evaluation of the two-limb parallel mechanism can be useful for possible applications in industry where a pick-and-place motion is required.


Robotica ◽  
2013 ◽  
Vol 31 (6) ◽  
pp. 935-944 ◽  
Author(s):  
Gang Cheng ◽  
Jingli Yu ◽  
Peng Xu ◽  
Houguang Liu

SUMMARYA novel parallel hip joint simulator, called 3SPS+1PS bionic parallel test platform, with 4 degrees of freedom including three rotations and one translation is designed to represent three-dimensional motion and compound friction movement of a human hip joint and to be a better simulator for testing the tribology performance of biomaterials for hip joint prosthesis. Stiffness is one of the most important performances of parallel manipulators, as well as for the 3SPS+1PS parallel manipulator with higher speeds. First, the differential kinematic/static model was derived based on the kinematics model. The relationship between the elastic deformation of each active leg and the variation of position/orientation deformation of the moving platform was described based on the virtual work principle. Then, a 6 × 6 global stiffness matrix of the 3SPS+1PS parallel manipulator was derived. The maximum versus minimum eigenvalues of the global stiffness matrix were obtained as its two evaluation indexes. By letting the 3SPS+1PS bionic parallel test platform represent three rotation motions and the dynamic loading of the human hip joint as described by ISO 14242 Part-1, the forces acted on each active leg and their responding elastic deformations were analyzed. The distributions for maximum and minimum stiffness in different workspace were detected. Finally, the results showed that the minimum stiffness in the whole workspace should be larger than the allowable stiffness of the 3SPS+1PS parallel manipulator.


2010 ◽  
Vol 143-144 ◽  
pp. 308-312 ◽  
Author(s):  
Yi Cao ◽  
Hui Zhou ◽  
Bao Kun Li ◽  
Shen Long ◽  
Meng Si Liu

This paper mainly addresses the principle of the singularity elimination of the Stewart parallel platform. By adding appropriate redundant actuation, the rank of the Jacobian matrix of the parallel platform is always full, accordingly the singular value of the Jacobian matrix of the parallel platform is nonzero. Then the singular configuration of the parallel platform can be eliminated by adding one redundant actuation. Numerical examples are taken to illuminate the principle’s effectiveness. It is shown that not only singular configurations of the Stewart parallel platform can be eliminated, but also performances of kinematics and dynamics of the parallel platform can be greatly perfected by adding appropriate redundant actuation.


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