【作者】 张杰；

【导师】 王立平；

【作者基本信息】 电子科技大学 ， 机械（专业学位）， 2025， 硕士

【摘要】 高端五轴数控系统在航空航天、精密制造和国防装备等领域广泛应用。然而,刀具路径的轨迹不连续性和进给速度的不稳定性会影响加工精度并降低机床使用寿命。本研究针对五轴数控加工的轨迹光顺及进给速度控制问题,提出五轴刀具路径转接光顺与进给速度规划方法,旨在提高机床的动态稳定性和加工效率。首先,设计了一种降低最大曲率的五轴刀具路径转接光顺方法。该方法考虑最大轮廓偏差约束,通过构造基于九个控制点的五次B样条(B-Spine)曲线,实现了刀具路径拐角处的转接光顺,降低了过渡段路径的最大曲率;针对非过渡段,通过参数化重构实现刀具路径的C~3连续。此外,采用两步投影法同步优化刀轴方向,避免了因刀具姿态突变导致的加工不稳定性。两个案例仿真结果表明,该方法使刀具路径的最大曲率分别降低了33.65%和29.22%。进一步,提出了一种多约束下的自适应进给速度规划方法。该方法包括离线进给速度规划和在线轨迹插补。首先,根据几何和法向驱动能力约束确定许用进给速度,根据曲率极大值点将刀具路径划分为多段子曲线。其次,在切向驱动能力约束下更新许用进给速度,并采用S型速度规划模型获取各子曲线内的初始进给速度。若初始进给速度超出许用范围,则动态更新子曲线参数并引入过渡区间;接着采用双向扫描生成过渡区间的进给速度,从而实现整体进给速度的平滑。为了提高在线插补精度,基于进给速度和曲线弧长,提出了改进的二阶Runge-Kutta插补方法。两个案例仿真结果表明,相比现有进给速度规划方法,所提方法的进给效率分别提升了46.73%和22.33%。最后,基于五轴数控系统平台,开展了本文中鞋子形、S形转接光顺案例和WM形、蝴蝶形进给速度规划案例的验证实验。实验结果和仿真结果一致,验证了所提转接光顺方法和进给速度规划方法的有效性。此外,欧模零件的试切实验验证了所提方法在实际工程应用中的可行性。更多还原

【Abstract】 Advanced five-axis CNC systems have been widely applied in aerospace,precision manufacturing,and national defense equipment.However,the discontinuity of the toolpath trajectory and instability of the feedrate can adversely affect machining accuracy and reduce machine tool life.In this thesis,trajectory smoothing and feedrate control methods for five-axis CNC machining were studied,and a novel five-axis toolpath corner smoothing and feedrate scheduling methods were proposed to improve the dynamic stability and machining efficiency of machine tools.First,a five-axis toolpath local smoothing method is developed to reduce the maximum curvature of the transition curves.The maximum contour deviation constraint was considered,and a quintic B-spline based on nine control points was constructed.Thus,toolpath corner smoothing was achieved,and the maximum curvature of transition segments was significantly reduced.For non-transition sections,C~3 continuity of the toolpath was ensured by reparameterization.In addition,a two-step projection method was adopted to optimize the tool orientation simultaneously,thereby preventing machining instability caused by sudden changes in tool orientation.Simulation results indicated that the proposed method reduced the maximum curvature of toolpaths by 33.65%and 29.22%,respectively.Furthermore,an adaptive feedrate scheduling method under multiple constraints is proposed.The proposed method consisted of offline feedrate scheduling and online trajectory interpolation.Initially,the allowable feedrate was determined based on geometric and normal drivability constraints,and the toolpath was segmented into sub-curves according to points of maximum curvature.Subsequently,according to tangential drivability constraints,the allowable feedrate was updated,and an S-shaped feedrate scheduling method was applied to determine the feedrate of each sub-curve.If the initial feedrate exceeded the allowable feedrate,the sub-curve parameters were dynamically updated,and transition intervals were introduced.A bidirectional scanning algorithm was then performed to generate smooth feedrates within these transition intervals,thus ensuring smooth overall feedrate profiles.To improve online interpolation accuracy,a second-order Runge-Kutta interpolation method based on parameter correction was proposed.Simulation results demonstrated that,compared to existing feedrate scheduling methods,machining efficiency improved by 46.73%and 22.33%,respectively.Finally,verification experiments were conducted on a five-axis CNC system platform using shoe-shaped and S-shaped cases for local smoothing,and WM-shaped and butterfly-shaped cases for feedrate scheduling.Experimental results were consistent with simulation results,verifying the effectiveness of the proposed local smoothing and feedrate scheduling methods.Additionally,cutting experiments on a European mold validated the feasibility of applying the proposed methods in practical engineering scenarios.更多还原