A General Kinetostatic Model Based Stiffness Estimation for Tripod Parallel Kinematic Machines with Prismatic Actuators

2017 ◽  
pp. 71-84
Author(s):  
Jun Zhang ◽  
Tengfei Tang
Keyword(s):  
Parallel Kinematic Machines ◽  
Model Based ◽  
Parallel Kinematic ◽  
Kinetostatic Model

scholarly journals Conceptual design and comparative stiffness analysis of an Exechon-like parallel kinematic machine with lockable spherical joints

2017 ◽  
Vol 14 (4) ◽  
pp. 172988141772413
Author(s):  
Teng-fei Tang ◽  
Jun Zhang
Keyword(s):  
Conceptual Design ◽  
Prediction Accuracy ◽  
Parallel Kinematic Machine ◽  
Stiffness Analysis ◽  
Parallel Kinematic Machines ◽  
Stiffness Model ◽  
Dynamic Analyses ◽  
Parallel Kinematic ◽  
Kinetostatic Model ◽  
Limb Structure

This article proposes two types of lockable spherical joints which can perform three different motion patters by locking or unlocking corresponding rotational axes. Based on the proposed lockable spherical joints, a general reconfigurable limb structure with two passive joints is designed with which the conceptual designs of two types of Exechon-like parallel kinematic machines are completed. To evaluate the stiffness of the proposed Exechon-like parallel kinematic machines, an expanded kinetostatic model is established by including the compliances of all joints and limb structures. The prediction accuracy of the expanded stiffness model is validated by numerical simulations. The comparative stiffness analyses prove that the Exe-Variant parallel kinematic machine claims competitive rigidity performance to the Exechon parallel kinematic machine. The present work can provide useful information for further investigations on structural enhancement, rigidity improvement, and dynamic analyses of other Exechon-like parallel kinematic machines.

scholarly journals Parallel Kinematic Machines: Design, Analysis and Simulation in an Integrated Virtual Environment

2004 ◽  
Vol 127 (4) ◽  
pp. 580-588 ◽  
Author(s):  
Dan Zhang ◽  
Lihui Wang ◽  
Sherman Y. T. Lang
Keyword(s):  
Machine Tool ◽  
Virtual Environment ◽  
Collision Detection ◽  
Design Analysis ◽  
Visual Environment ◽  
Parallel Kinematic Machines ◽  
Virtual System ◽  
Parallel Kinematic ◽  
Optimization And Simulation ◽  
Kinetostatic Model

Selecting a configuration for a machine tool that will best suit the needs of a forecast set of requirements can be a difficulty and costly exercise. This problem can now be addressed using an integrated virtual validation system. The system includes kinematic/dynamic analysis, kinetostatic model, CAD module, FEM module, CAM module, optimization module and visual environment for simulation and collision detection of the machining and deburring. It is an integration of the parallel kinematic machines (PKM) design, analysis, optimization and simulation. In this paper, the integrated virtual system is described in detail; a prototype of a 3-dof PKM is modeled, analyzed, optimized and remote controlled with the proposed system. Some results and simulations are also given. Its effectiveness is shown with the results obtained by NRC-IMTI during the design of the 3-dof NRC PKM.

Some Implications for Parallel Kinematic Machine Design Based on Kinetostatic Model

2000 ◽  
Author(s):  
Clément M. Gosselin ◽  
Dan Zhang
Keyword(s):  
Material Properties ◽  
Geometric Model ◽  
Design Guidelines ◽  
Machine Design ◽  
Parallel Kinematic Machine ◽  
System Behavior ◽  
New Type ◽  
Link Flexibility ◽  
Parallel Kinematic ◽  
Kinetostatic Model

Abstract In this paper, a new method — named lumped kinetostatic modeling — to analyze the effect of the link flexibility on the mechanism’s stiffness is provided. A new type of mechanism whose degree of freedom (dof) is dependent on a passive constraining leg connecting the base and the platform is introduced and analyzed. With the proposed kinetostatic model, a significant effect of the link flexibility on the mechanism’s precision has been demonstrated. The influence of the changement of structure parameters, including material properties, on the system behavior is discussed. In the paper, the geometric model of this kind of mechanism is first introduced. Then, a lumped kinetostatic model is proposed in order to account for joint and link compliances; some results and design guidelines are obtained. Finally, the optimization of the precision is addressed using a genetic algorithm.

Error Sensitivity Analysis for Optimal Calibration of Parallel Kinematic Machines

2002 ◽  
Author(s):  
Fengfeng Xi ◽  
Marcel Verner ◽  
Chris Mechefske
Keyword(s):  
Sensitivity Analysis ◽  
Error Model ◽  
Condition Numbers ◽  
Geometric Errors ◽  
Error Sensitivity ◽  
Parallel Kinematic Machines ◽  
Parallel Kinematic ◽  
Error Sensitivity Analysis ◽  
Jacobian Inverse ◽  
Optimal Calibration

In this paper, error sensitivity analysis is discussed for the purpose of optimal calibration of parallel kinematic machines (PKMs). The idea is to find a less error sensitive area in the workspace for calibration. To do so, an error model is developed that takes into consideration all the geometric errors due to imprecision in manufacturing and assembly. Based on this error model, it is shown that the error mapping from the geometric errors to the pose error of the PKM depends on the Jacobian inverse. The Jacobian inverse would introduce spurious errors that would affect the calibration results, if used without proper care. Hence, it is suggested to select the areas in the workspace with smaller condition numbers for calibration. A case study is presented to illustrate the proposed method.

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