Papers by Author: Bo Qian

Abstract: An image mapping algorithm is proposed to improve the precision of flexible roll forming. The mapping algorithm based on visual feedback and Image analysis technology. On-line detection device realizes image acquisition of cross-section profile. After processing and analysis, geometric feature is extracted by Hough transform in the image. Geometric feature is transformed to matrix which is built a mapping relation with the original matrix. The mapping algorithm describes the displacement and rotary error in the process of flexible roll forming. Closed loop control is realized by feeding back the error to the control system. Experiments results show that the mapping algorithm is a good algorithm for on-line dimensional precision detection in sheet metal forming.

Abstract: For the flexible roll forming of the control system, this paper introduces a method that machine vision bind to the flexible roll forming control system. The detection method for sheet metal forming is image acquisition, image processing and other means for the extraction of sheet metal forming in some time section contour curve. Compare extraction section contour curve with the moment theory section contour curve in the control system, get the deviation value and feedback to the control system that interpolation arithmetic to realize closed loop control.

Abstract: How to manufacture high accuracy, complex section, high strength steel products is the current challenge of flexible roll forming technology. This article introduced opening NC system application in flexible roll forming, both in software and in hardware. As the core module of the software system, the interpolation module was discussed. The article mainly focused on how to establish track simulation module. According to the algorithm, we calculated the roller displacement and rotation angle using VC++. At last the simulation processes and results were presented, which prove the trace interpolation algorithm is correct and feasible.

Abstract: Due to the complex motion control in flexible roll forming when processing the sheet metal with variable cross-section, it is required for high real-time and high precision control during the processing. Controlling servo motor by adopting the configuration programming is a common approach to achieve roller motion, but it will not be able or difficult to realize by the configuration programming for complex contour sheet metal without the rules such as hyperbolic, or the molding product in non-symmetric cross-section shape, etc. Based on the process characteristic of flexible roll forming and its motion control technology, this paper adopts the variable time-domain discrete interpolation control method to process the variable cross-section sheet metal. Experiments indicate that this control method provides a good operating method for the sheet metal forming with complex variable cross-section shape in flexible roll forming.

Abstract: In flexible roll forming, the horizontal movable sheet steel can be formed by controlling the servo motor to drive the multi-pass vertical movable roll. Only when the longitudinal movable distance of the roll in every pass matches exactly the contours of the sheet steel in time and space, the designated cross-section shape can be formed. Controlling the servo motor by applying the configuration programming is a common approach to achieve roll motion, but will not be able or difficult to realize by the configuration programming for complex contour without the rules such as hyperbolic, or the molding product in asymmetric cross-section shape, however, there are two other approaches such as simplifying the curves and using similar shapes to fit the process. As for the complex non-symmetrical curvature shapes, this paper adopts the variable time-domain servo motion control method to form the sheet steel. Experiments show that the variable time-domain servo motor control is a good motion control method for the sheet steel forming in complex cross-section shape.

Abstract: In sterolithgraphy rapid prototyping, the support can constraint the parts deformation, and avoid a lot of problems such as collapse, shift and imbalance of the parts. It is of great importance in improving the overall efficiency of rapid prototyping technics software through enhancing the support generation efficiency. Based on this, this paper proposes a discrete-marking support algorithm for treatment of processing on manufactured part model of all Triangle-based discrete-marking on the support plane. The new mesh discrete-marking and automatic support generation algorithm has been successfully applied to the Sterolithography apparatus (SLA). Practical application indicates that the new support generation algorithm improve considerably the support technics efficiency.