摘要
对机床传动系统、伺服驱动系统和数控插补模块进行动力学建模和求解。提出一种新的NURBS插补算法,按照进给率自适应轨迹规划算法进行当前插补周期的速度设定,并且根据曲线当前位置的曲率特性,进行基于曲率的最大速度限定,通过求解动力学模型,获得按照这一速度进行插补时系统需要的最大驱动力,若该驱动力超过系统能够提供的最大驱动力,则再次按照用户设定的加速度进行减速,获得的速度作为指令速度,按照一阶泰勒展开近似进行插补点的计算。该算法不仅在NURBS曲率较大的区域自动降低进给速度,保证要求的弦误差,而且使输出的插补速度指令区域平滑,保证不会出现插补输出的位置值系统无法进行位置控制造成更大的加工误差。
For dynamics modelling and solution of machine drive system, servo drive system and NC interpolation module, a new NURBS interpolation algorithm is proposed. In every interpolator period the reference velocity is set by the trajectory planner, then according to the geometry characteristics the maximum velocity is limited to meet the chord error demand. The dynamic equations are solved to calculate the needed torque if the reference velocity is transported to servo unit. If the needed torque is greater than maximum one that servo system can provide, a proper deceleration is applied for decreasing the reference velocity. At last first-order Taylor＇s expansion approximation is employed to calculate the new interpolation point. This algorithm can adjust the feedrate where the curvature is great, so as to meet the requirement on chord error, and make the interpolation velocity instruction area smooth. This algorithm can ensure the servo units to achieve the interpolation point in time, thus avoiding machining error.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2009年第12期187-191,197,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(50775029)
关键词
NURBS插补
机床动力学
速度自适应
弦误差
曲率
NURBS interpolator Dynamics of machine tools Adaptive feedrate Chord error Curvature
