Accuracy Analysis of Parallel Manipulators With Joint Clearance

Abstract

Due to joint clearance, a parallel manipulator’s end-effector exhibits position and orientation (or collectively referred to as pose) errors of various degrees. This paper aims to provide a systematic study of the error analysis problem for a general parallel manipulator influenced by joint clearance. We propose an error prediction model that is applicable to planar or spatial parallel manipulators that are either overconstrained or nonoverconstrained. By formulating the problem as a standard convex optimization problem, the maximal pose error in a prescribed workspace can be efficiently computed. We present several numerical examples to show the applicability and the efficiency of the proposed method.

Output error bound prediction of parallel manipulators based on the level set method

“…Meanwhile, Briot et al [16] generalized the interval analysis of accuracy analysis for several 3-DOF planar parallel manipulators and gave a detailed mathematical proof. Recently, Li et al [17] formulated the accuracy analysis of parallel manipulators as a standard convex optimization problem, which can predict the maximal pose errors caused by the joint clearances for an arbitrary configuration in the prescribed workspace. However, among the existing researches, most of them formulated the error model based on the forward kinematics of parallel manipulators, which is relatively complicated and computer-intensive in calculation and encounters the multiple solutions problem as well [18,19].…”

Mobile Assemblies of Large Deployable Mechanisms

“…Therefore, better errors tolerant ability, which measures the ability of the mechanisms to retain the necessary mobility and still be movable under the possible geometric dimensional errors, is very important for this kind of mechanisms. So far, there are still very limited literatures on the mobile assembly problems of the large deployable mechanisms, especially for the overconstrained problem in the large deployable mechanical networks, although there are some literatures on the assembly problem of the overconstrained parallel manipulators [6] .…”

“…Joint clearance is essential for correct functioning and easy assembly of the underlying mechanisms [6] . Therefore, better errors tolerant ability, which measures the ability of the mechanisms to retain the necessary mobility and still be movable under the possible geometric dimensional errors, is very important for this kind of mechanisms.…”

Normalized-constrained approach for joint clearance design of deployable overconstrained Myard 5R mechanism

“…In order to ensure the mobility of the mechanisms, joint clearance is necessary and inevitable in mechanism design. Joint clearance is also designed for the cost reduction of the manufacturing, prestressing force reduction and easy of assembly of the complicated overconstrained mechanisms (Jian Meng, et al, 2009). For deployable mechanisms work in the space environment, the joint clearance is necessary to make the mechanisms adapt to the possible thermal deformations which will change the dimensions of the mechanical parts of the deployable mechanisms.…”