Locating Scheme Planning Algorithm based on Positioning Normal Line and Analytical Hierarchy Process

Abstract Planning methods tailored for individual stages of locating schemes often fall short of achieving overall optimization. Therefore, by employing the positioning normal line as a medium and based on the geometric theorem of workpiece locating concerning the positioning normal line, the relationship between workpiece degrees of freedom and the positioning normal line can be deduced. This enables the acquisition of positioning normal line information for the freedom constraint model, consequently deriving an initial layout for the locating points. This initial layout sieves through all surfaces of the workpiece, establishing a set of candidate locating references. The intrinsic conditions of the workpiece surfaces, alongside the corresponding clamping surface quality, are utilized as measures to gauge their locating capabilities. Aiming for optimal locating capabilities, the Analytic Hierarchy Process (AHP) is employed to ascertain a comprehensive, optimal vector encompassing the combined locating capabilities of various workpiece surfaces, aiding in the selection of locating references. The feasibility of this method is validated through practical examples. Results demonstrate that the layout of locating points planned using this method, in conjunction with the positioning normal information provided by different characteristic types as summarized in this paper, effectively guides machining personnel in formulating locating schemes.