Advances in Manufacturing ›› 2023, Vol. 11 ›› Issue (1): 111-129.doi: 10.1007/s40436-022-00413-1

• • 上一篇    

Improved time-optimal B-spline feedrate scheduling for NURBS tool paths in CNC machining

Yang Li1, Fu-Sheng Liang2, Lei Lu2, Cheng Fan2   

  1. 1. School of Mechanic Engineering, Northeast Electric Power University, Jilin, 132012, Jilin, People's Republic of China;
    2. Jiangsu Provincial Key Laboratory of Advanced Robotics and Collaborative Innovation Center of Suzhou Nano Science and Technology, College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215021, Jiangsu, People's Republic of China
  • 收稿日期:2021-09-07 修回日期:2022-02-11 发布日期:2023-02-16
  • 通讯作者: Cheng Fan,E-mail:chfan@suda.edu.cn E-mail:chfan@suda.edu.cn
  • 作者简介:Yang Li is an associate professor at the School of Mechanical Engineering, Northeast Electric Power University, Jilin, China. He received his PhD in Mechanical Manufacturing from Jilin University. His research interests include error measurement, error modeling and error compensation of machine tools, precision measurement, and processing;
    Fu-Sheng Liang is an associate professor in School of Mechanical and Electrical Engineering of Soochow University. He was a postdoctoral researcher in the Centre of Micro/Nano Manufacturing Technology (MNMTDublin) situated in the Engineering and Materials Science Centre, at University College Dublin since 2018. He holds a PhD (2018) in Mechanical Engineering, from Jilin University. His current research centers on CNC machining and digital manufacturing of freeform surfaces with high precision;
    Lei Lu received the Ph.D. degree in Mechanical Engineering from Jilin University, China, in 2016. He is currently an assistant professor with the Soochow University. He was a research fellow with the Department of Mechanical Engineer ing, National University of Singapore, Singapore, since 2019. His research interests include robotic machining, sculptured surface machining, and tool-path generating;
    Cheng Fan born in 1986, is an associate professor in School of Mechanical and Electrical Engineering of Soochow University. He received his Ph.D in School of Mechanical Science and Engineering of Jilin University. His research interests include precision polishing and bionic sensor.

Improved time-optimal B-spline feedrate scheduling for NURBS tool paths in CNC machining

Yang Li1, Fu-Sheng Liang2, Lei Lu2, Cheng Fan2   

  1. 1. School of Mechanic Engineering, Northeast Electric Power University, Jilin, 132012, Jilin, People's Republic of China;
    2. Jiangsu Provincial Key Laboratory of Advanced Robotics and Collaborative Innovation Center of Suzhou Nano Science and Technology, College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215021, Jiangsu, People's Republic of China
  • Received:2021-09-07 Revised:2022-02-11 Published:2023-02-16
  • Supported by:
    The authors would like to thank the finical support from Scientific Research Projects of Jilin Provincial Department of Education (Grant No. JJKH20200104KJ) and National Natural Science Foundation of China (Grant No. 51975392).

摘要: Feedrate scheduling in computer numerical control (CNC) machining is of great importance to fully develop the capabilities of machine tools while maintaining the motion stability of each actuator. Smooth and time-optimal feedrate scheduling plays a critical role in improving the machining efficiency and precision of complex surfaces considering the irregular curvature characteristics of tool paths and the limited drive capacities of machine tools. This study develops a general feedrate scheduling method for non-uniform rational B-splines (NURBS) tool paths in CNC machining aiming at minimizing the total machining time without sacrificing the smoothness of feed motion. The feedrate profile is represented by a B-spline curve to flexibly adapt to the frequent acceleration and deceleration requirements of machining along complex tool paths. The time-optimal B-spline feedrate is produced by continuously increasing the control points sequentially from zero positions in the bidirectional scanning and sampling processes. The required number of knots for the time-optimal B-spline feedrate can be determined using a progressive knot insertion method. To improve the computational efficiency, the B-spline feedrate profile is divided into a series of independent segments and the computation in each segment can be performed concurrently. The proposed feedrate scheduling method is capable of dealing with not only the geometry constraints but also high-order drive constraints for any complex tool path with little computational overhead. Simulations and machining experiments are conducted to verify the effectiveness and superiorities of the proposed method.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00413-1

关键词: B-spline feedrate, Non-uniform rational B-splines (NURBS) tool path, Knot insertion, Bidirectional scanning, Computer numerical control (CNC) machining

Abstract: Feedrate scheduling in computer numerical control (CNC) machining is of great importance to fully develop the capabilities of machine tools while maintaining the motion stability of each actuator. Smooth and time-optimal feedrate scheduling plays a critical role in improving the machining efficiency and precision of complex surfaces considering the irregular curvature characteristics of tool paths and the limited drive capacities of machine tools. This study develops a general feedrate scheduling method for non-uniform rational B-splines (NURBS) tool paths in CNC machining aiming at minimizing the total machining time without sacrificing the smoothness of feed motion. The feedrate profile is represented by a B-spline curve to flexibly adapt to the frequent acceleration and deceleration requirements of machining along complex tool paths. The time-optimal B-spline feedrate is produced by continuously increasing the control points sequentially from zero positions in the bidirectional scanning and sampling processes. The required number of knots for the time-optimal B-spline feedrate can be determined using a progressive knot insertion method. To improve the computational efficiency, the B-spline feedrate profile is divided into a series of independent segments and the computation in each segment can be performed concurrently. The proposed feedrate scheduling method is capable of dealing with not only the geometry constraints but also high-order drive constraints for any complex tool path with little computational overhead. Simulations and machining experiments are conducted to verify the effectiveness and superiorities of the proposed method.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00413-1

Key words: B-spline feedrate, Non-uniform rational B-splines (NURBS) tool path, Knot insertion, Bidirectional scanning, Computer numerical control (CNC) machining