Robust Isotropic Residual-Constrained VMD: A Novel Filter for Analyzing Engineering Surface Topography

Surface topography filtering is a commonly used technique in various fields, and over the years, a variety of filters have been included in international standards. However, traditional filtering methods continue to suffer from significant fitting errors in the separation of surface topography (form, waviness and roughness). To address these issues, this study proposes a new filter algorithm based on an improved VMD method that incorporates some VME algorithm ideas. The proposed filter analyzes surface topography through three pivotal steps: Firstly, it derives the optimal robust weighting function. Secondly, it integrates the weighting function into the isotropic residual constraint VMD to decompose the surface into several isotropic modes (sub-surfaces). Ultimately, it quantitatively computes and combines the sub-surfaces to reconstruct the topography of each surface. Numerical simulation experiments illustrate that the proposed algorithm outperforms advanced surface filters, significantly reducing fitting errors of surface topography separation including areal-VMD-based filters. Finally, two grinding workpieces are analyzed using the proposed algorithm to demonstrate its effectiveness in evaluating machined surfaces, revealing the analytical process and presenting the results.