摘要：
目前数控加工参数曲线轨迹时,常采用连续线性小线段逼近的方法来克服参数曲线的复杂计算需求.但是,有限的驱动能力和线段连接处存在切向不连续,使得在这些拐点处速度必须降低到零,这种频繁加减速会降低加工效率和表面加工质量.为此,提出一种基于羊角曲线的过渡曲线光顺方法,能够实现加工轨迹的G2连续、轮廓误差可控和光顺速度非零的运动效果.首先,基于几何约束计算出拐角处的光顺曲线几何特征和弧长;其次,基于几何特征和运动学约束,通过双向看策略获得速度敏感点的允许速度.最后,确定速度规划和生成精细插补指令.仿真结果表明,该方法能够满足预先设定的轮廓误差,可有效实现拐角点的速度光顺,缩短加工时间.%At present, the method of continuous linear small line segment approximation is often used to overcome the complex calculation of parameter curve in NC machining. However, there is limited driving capacity and tangential discontinuity at the junctions of the continuous line segment, which reduces the feedrate to zero at these corner points. This frequent acceleration and deceleration will reduce the machining efficiency and surface quality. A transition curve smoothing method based on clothoid curves is proposed, and it can achieve the G2 continuous machining path, controllable approximation error and non-zero smoothing feedrate. Firstly, geometric characteristics and arc length of smoothing curves at corners are calculated based on geometric constraints. Secondly, the allowable feedrate of feedrate sensitive points is obtained through bidirectional scanning, based on geometric characteristics and kinematic constraints. Finally, the feedrate scheduling and the generation of interpolation instructions are determined.The simulation results show that this method can satisfy the pre-set approximation error, effectively realize the feedrate smoothing of corner points, and shorten the processing time.
