The Nonlinear Buckling Ananysis Of Steel-Band Driven Parallel Robot

This paper proposes a new kind of parallel robot adopting thin-wall steel band as its support part that has the characteristic of buckling instability. When steel band stretches out and draws back around the coiling, its arc-shaped cross section would be spreaded from arc to straight. This process is considered to be including geometrical nonlinearity and not to be researched. Therefore, the nonlinear buckling analysis is very significant not only for a single steel band but also for the steel-band driven parallel robot as a whole.This paper is mainly related to the nonlinear buckling analysis of a single steel band and the steel-band driven parallel robot as a whole. The research contents are shown as follows:1. In section2, as thin-wall steel band with uniform arc-shaped cross section has the characteristic of buckling, it is necessary to introduce the types and properties of structural instability; the finite element analysis principles and procedures of linear buckling analysis and non-linear buckling analysis; the stiffness matrix of shell element and the finite element formulas of nonlinear buckling analysis.2. In section3, for different simplified thin-wall steel bands with variable cross-section and thin-wall steel bands with uniform arc-shaped cross section in thickness, length and central angle, linear and nonlinear buckling analyses are carried out by adopting solid element and shell element respectively. Through above three simulation schemes, the relationships between structural parameters and the critical instability load are obtained. Furthermore, the connection and distinction between linear buckling analysis and nonlinear buckling analysis are also found. The type of steel-band instability is learned by the post-buckling analysis for the thin-wall steel band with uniform arc-shaped cross section.3. Then in Section4, by comparing experimental results with simulation results in three ways, it is found that the simulation results from nonlinear buckling analysis adopting shell element fit best to experimental results.4. As far as three basic motion forms of translation, torsion and rotation of mobile platform are concerned, nonlinear buckling analysis based on the linear buckling analysis is carried out on the steel-band driven parallel robot by adopting shell element and solid element to obtain the relationships between critical instability load and the motion parameters of above three basic motion forms.