高速数控加工的速度自适应三次多项式前瞻插补算法研究与实现
发布时间：2018-09-01 16:41
【摘要】：高速数控加工系统在现代制造业中占据至关重要的地位,进给速度和加工精度是评价该系统性能的关键性指标。在高速加工过程中,速度突变点的存在造成进给速度和进给方向急剧变化,严重影响加工精度。因此,前瞻插补技术被引入到数控系统中并得到了广泛应用,较好地解决了这个问题。为了在数控加工中预先发现速度突变点、平稳经过插补点和防止速度突变引起的机床振动,本文结合NURBS曲线插补,提出了速度自适应三次多项式前瞻插补算法,并且建立了该算法的通用模型。首先根据NURBS曲线的相关计算值,由曲线中插补点曲率的变化总结了速度突变点的判定标准,确定了速度突变点的位置。接着根据速度突变点对加工曲线进行分段处理,提出了基于弓高误差和三次多项式加减速的突变点速度局部最优解。然后通过分析突变点处速度的嵌套关系,给出了前瞻距离的有效计算方法。最后根据计算减速点位置的要求,在前瞻范围内进行反向插补,提出了进给速度的实时优化方案。本文通过两种不同的轨迹曲线对提出的速度自适应三次多项式前瞻插补算法进行了仿真验证,并与基于S型加减速算法和传统三次多项式加减速算法进行了性能对比仿真,结果验证了该算法比S型加减速算法的运行时间减少了1.62%,比传统三次多项式加减速算法的最大弓高误差减少了6.77‰。此外,本算法在润金科技数控加工平台中进行了试用,其单次插补时间最大为0.261ms,完全满足该系统设定最大插补时间1ms的要求。
[Abstract]:High-speed NC machining system plays an important role in modern manufacturing industry. Feed speed and machining precision are the key indexes to evaluate the performance of the system. In the process of high speed machining, the existence of the sudden change of speed caused the sharp change of feed speed and feed direction, which seriously affected the machining accuracy. Therefore, the forward-looking interpolation technology is introduced into the CNC system and widely used to solve this problem. In order to detect the mutation point in advance, pass through the interpolation point smoothly and prevent the vibration of the machine tool caused by the sudden change of speed in NC machining, this paper presents an algorithm of speed adaptive cubic polynomial forward interpolation combined with NURBS curve interpolation. A general model of the algorithm is established. First, according to the relative calculation value of NURBS curve, the determination standard of velocity catastrophe point is summarized from the curvature change of interpolation point in the curve, and the position of velocity catastrophe point is determined. Then the processing curve is segmented according to the velocity catastrophe point, and the local optimal solution of the abrupt point velocity is proposed based on the error of arch height and the acceleration and deceleration of cubic polynomial. Then, by analyzing the nested relation of the velocity at the sudden change point, the effective calculation method of the forward distance is given. Finally, according to the requirement of calculating the position of deceleration point, reverse interpolation is carried out in the forward range, and the real-time optimization scheme of feed speed is put forward. In this paper, two different trajectory curves are used to verify the proposed algorithm, and the performance of the proposed algorithm is compared with that based on S-type acceleration and deceleration algorithm and traditional cubic polynomial acceleration and deceleration algorithm. The results show that the running time of this algorithm is 1.62 less than that of S-type acceleration and deceleration algorithm, and the maximum bow height error of the traditional cubic polynomial acceleration and deceleration algorithm is 6.77 鈥，
本文编号：2217769
[Abstract]:High-speed NC machining system plays an important role in modern manufacturing industry. Feed speed and machining precision are the key indexes to evaluate the performance of the system. In the process of high speed machining, the existence of the sudden change of speed caused the sharp change of feed speed and feed direction, which seriously affected the machining accuracy. Therefore, the forward-looking interpolation technology is introduced into the CNC system and widely used to solve this problem. In order to detect the mutation point in advance, pass through the interpolation point smoothly and prevent the vibration of the machine tool caused by the sudden change of speed in NC machining, this paper presents an algorithm of speed adaptive cubic polynomial forward interpolation combined with NURBS curve interpolation. A general model of the algorithm is established. First, according to the relative calculation value of NURBS curve, the determination standard of velocity catastrophe point is summarized from the curvature change of interpolation point in the curve, and the position of velocity catastrophe point is determined. Then the processing curve is segmented according to the velocity catastrophe point, and the local optimal solution of the abrupt point velocity is proposed based on the error of arch height and the acceleration and deceleration of cubic polynomial. Then, by analyzing the nested relation of the velocity at the sudden change point, the effective calculation method of the forward distance is given. Finally, according to the requirement of calculating the position of deceleration point, reverse interpolation is carried out in the forward range, and the real-time optimization scheme of feed speed is put forward. In this paper, two different trajectory curves are used to verify the proposed algorithm, and the performance of the proposed algorithm is compared with that based on S-type acceleration and deceleration algorithm and traditional cubic polynomial acceleration and deceleration algorithm. The results show that the running time of this algorithm is 1.62 less than that of S-type acceleration and deceleration algorithm, and the maximum bow height error of the traditional cubic polynomial acceleration and deceleration algorithm is 6.77 鈥，
本文编号：2217769
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