Parametric stiffness analysis of the Orthoglide
TL;DR: In this article, a parametric stiffness analysis of the Orthoglide was performed and a compliant modeling and a symbolic expression of the stiffness matrix were conducted. Butler et al. presented a simple systematic analysis for the influence of the geometric design parameters and identified the critical link parameters.
About: This article is published in Mechanism and Machine Theory.The article was published on 2007-03-01 and is currently open access. It has received 132 citations till now. The article focuses on the topics: Direct stiffness method & Stiffness matrix.
Citations
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TL;DR: A new stiffness modeling method for overconstrained parallel manipulators with flexible links and compliant actuating joints is presented, based on a multidimensional lumped-parameter model that replaces the link flexibility by localized 6-dof virtual springs that describe both translational/rotational compliance and the coupling between them.
271 citations
TL;DR: In this paper, a non-linear stiffness model for serial and parallel manipulators with passive joints is presented, where the manipulator elements are presented as pseudo-rigid bodies separated by multidimensional virtual springs and perfect passive joints.
221 citations
15 May 2006
TL;DR: The proposed analytical method could be used to reduce the gap existing between actual PKM and those that have to meet the high accuracy specifications required for machining applications.
Abstract: The purpose of this work is to propose a new approach for the calculation of PKM stiffness matrix by using an analytical method based on matrix structural analysis. This method has as the main advantage to be systematic and it also can be applied to hyper-static PKM stiffness analysis. The implementation of the proposed method is fast and convenient and it can easily be involved during PKM design optimization. Moreover, as the stiffness matrix is obtained in a close form, it can be implemented directly on the robot controller. In other words, the proposed method could be used to reduce the gap existing between actual PKM and those that have to meet the high accuracy specifications required for machining applications. At first this paper presents the proposed analytical method that is applied to calculate the stiffness matrix of a delta parallel structure. Then the experimental results that have been done to evaluate and validate its efficiency are presented
156 citations
Abstract: Stiffness analysis and experimentof a novel 5-DoF parallel kinematic machine considering gravitational effects
108 citations
References
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01 Jun 1990
TL;DR: The approach used by the author is to establish stiffness or conditioning maps of the workspace of the manipulator, which reveal the existence of zones where the stiffness is not acceptable and also help the designer by providing a more accurate representation of the properties of the manipulation.
Abstract: Mechanical systems containing closed-loop kinematic chains can exhibit special types of singularities that result in a loss of controllability of the element of interest (output link or gripper link). Therefore, it is very important for the designer to be able to predict this type of behavior. The approach used by the author is to establish stiffness or conditioning maps of the workspace of the manipulator. A method for obtaining these maps for planar and spatial parallel manipulators is presented. The maps reveal the existence of zones where the stiffness is not acceptable and also help the designer by providing a more accurate representation of the properties of the manipulator. >
515 citations
TL;DR: In this paper, the structural characteristics associated with parallel manipulators are investigated and a class of 3 degree-of-freedom (3-UPUF) manipulators with only translational degrees of freedom are identified.
Abstract: The structural characteristics associated with parallel manipulators are investigated. Using these characteristics a class of 3 degree-of-freedom parallel manipulators are enumerated. Several parallel manipulators with only translational degrees of freedom are identified and the 3-UPU parallel manipulator is chosen for design analysis and optimization. The kinematics of this 3-UPU parallel manipulator is studied. Two geometric conditions that lead to pure translational motion of the moving platform are described. Due to the simple kinematic structure, the inverse kinematics yields two equal and opposite limb lengths whereas the direct kinematics produces two possible manipulator postures with one being the mirror image of the other. The Jacobian matrix is derived and several singular conditions are discussed. Furthermore the conditions for existence of an isotropic point within the workspace are discussed and equations to compute the isotropic configurations of a 3-UPU manipulator are derived. Finally, we undertake architecture optimization and show that certain values of design variables maximize the global condition index of the 3-UPU manipulator.
306 citations
25 Jun 2003
TL;DR: The Orthoglide as discussed by the authors is a three-degree-of-freedom translational parallel mechanism designed for machining applications with a regular Cartesian workspace shape, uniform performances in all directions, and good compactness.
Abstract: This paper addresses the architecture optimization of a three-degree-of-freedom translational parallel mechanism designed for machining applications. The design optimization is conducted on the basis of a prescribed Cartesian workspace with prescribed kinetostatic performances. The resulting machine, the Orthoglide, features three fixed parallel linear joints which are mounted orthogonally, and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The interesting features of the Orthoglide are a regular Cartesian workspace shape, uniform performances in all directions, and good compactness. A small-scale prototype of the Orthoglide under development is presented at the end of this paper.
304 citations
TL;DR: A new three-degrees-of-freedom (3-DOF) translational parallel manipulator (TPM) with linear actuators, i.e., 3-CRR TPM, is first proposed and shows that it has the following kinematic merits over previous TPMs.
Abstract: A new three-degrees-of-freedom (3-DOF) translational parallel manipulator (TPM) with linear actuators, i.e., 3-CRR TPM, is first proposed. The rotation singularity analysis, the inverse kinematics, the forward kinematics, and the kinematic singularity analysis of the 3-CRR TPM are then performed. The analysis shows that the proposed TPM has the following kinematic merits over previous TPMs. (1) The forward displacement analysis can be performed by solving a set of linear equations. (2) The Jacobian matrix of the TPM is constant. The inverse of the Jacobian matrix can be pre-calculated, and there is no need to calculate repeatedly the inverse of the Jacobian matrix in performing the forward displacement analysis and forward velocity analysis. (3) There is no rotation singularity. (4) There is no uncertainty singularity. (5) The TPM has a fewer number of links or joints. The geometric condition for a 3-CRR TPM to be isotropic is also revealed. Two additional kinematic merits exist for the isotropic 3-CRR TP...
199 citations
TL;DR: In this paper, the authors compared the performance of Cartesian Kinematics Machining Center (MC) structures with parallel kinematics hexapods (HX) structures from the point of view of workspace, stiffness, accuracy, acceleration ability, and motion dynamics for use as high speed milling machines.
177 citations