Geometric characterization of moldboard plough using coupled close photography and surface fitting model

Abstract

Designing a moldboard plow is a complex task. In many cases, moldboard plows are manufactured mostly based on experience and empirical methods The objective of this study is to identify a way to use a mathematical approach for the design. Therefore, both the mathematical surface (multi variable equations, NURBS and Bezier) and the number of control points required for its adjustment (A, B, C, D), are examined to produce optimal modeling of the semi helical moldboard plough geometry. The 3D coordinates of 196 marked points on the plough surface were acquired using image processing techniques. The results obtained indicate that the surface of the moldboard plough can be shaped with R2=0.81 and RMSE=13.35, by the adjustment of a coupled fifth-order polynomial, exponential and sinus functions. Furthermore, the guide curve and angles of generatrix lines can be represented with a coupled first-order polynomial, exponential and sinus functions and fourth-order polynomial function, respectively, by high R2=0.9998 and low RMSE=8.5×10−5. Overall the results confirmed that our method is suitable and effective for designing the moldboard plough.