Research On Tangent Motion Control Algorithm And Its Application In CNC Cloth Cutting Machine

With the quick development of light industry, the CNC cloth cutting machine and CNC jacquard machine as the core of the CAD/CAM system and automation production line of clothing industry and textile industry becomes the important subject researched. The interpolation function is the symbol of advanced CNC system. Moreover the stability and accuracy of interpolation algorithm will influence the performance index of CNC system directly. Accounting to motion characteristic of these equipments, the thesis carried on the research to tangent motion control algorithm of various curves and completed cutting motion emulation of garment piece in response to the result of interpolation.First, the machine structure, control system, cutting process, and motion feature of the CNC cloth cutting machine are introduced. Then, the tangent motion control algorithm is brought forward.In accordance with the requirement of tangent motion control, line tangent motion control algorithm and arc tangent motion control algorithm basing on the principle of the time-slicing method are researched. These algorithms improve conventional algorithm, add simultaneous control of the C axis, and realize identical programming in four different quadrant and automatic passing quadrant. Through programming to algorithms and interpolating of special straight-line and arc, and analyzing interpolation result, it is found that these algorithms can satisfy request of tangent motion control and interpolation error can satisfy request to machining error.Aim at the contour curve characteristic of the machining object, parameter curve and spline curve tangent interpolation algorithm is researched. An all-purpose variation step-length heuristic correction tangent interpolation algorithm is put forward, after analyzing and comparing various curve interpolation algorithm in detail. This algorithm bases on improving to heuristic correction interpolation algorithm and adds simultaneous control of the C axis and step length control along with curvature change of curve. It is used to tangent motion control of common parameter curve and cubic parameter spline curve and Bezier spline curve and B spline curve. In curve tangent motion control calculation of Bezier spline curve and B spline curve, de Casteljau algorithm and B spline recursion formula is used to calculate coordinate value of points avoiding complex calculate of spline curve parameter equation and making the algorithm simpler. Through programming to algorithm and interpolating to special parameter curve and spline curve and analyzing interpolation result, it is found that these algorithms can assure curve shape by changing step length along with curvature change of curve and satisfy request of tangent motion and interpolation error can satisfy request to machining error.Finally, cutting motion emulation of garment piece basing on tangent motion control is realized, by constructing the CNC cloth cutting machine model with Pro/ENGINEER software and interpolating to contour curve of garment piece with programming and by controlling motion trace of model with interpolation result. It lays the foundations of further application in engineer.