Taiyong Wang

Space cutter compensation method for five-axis nonuniform rational basis spline machining

In view of the good machining performance of traditional three-axis nonuniform rational basis spline interpolation and the space cutter compensation issue in multi-axis machining, this article presents a triple nonuniform rational basis spline five-axis interpolation method, which uses three nonuniform rational basis spline curves to describe cutter center location, cutter axis vector, and cutter contact point trajectory, respectively. The relative position of the cutter and workpiece is calculated under the workpiece coordinate system, and the cutter machining trajectory can be described precisely and smoothly using this method. The three nonuniform rational basis spline curves are transformed into a 12-dimentional Bézier curve to carry out discretization during the discrete process. With the cutter contact point trajectory as the precision control condition, the discretization is fast. As for different cutters and corners, the complete description method of space cutter compensation vector is presented in this article. Finally, the five-axis nonuniform rational basis spline machining method is further verified in a two-turntable five-axis machine.

Design and implementation of CNC controllers using reconfigurable hardware

The reconfigurable hardware has been widely applied in Computer Numerically Controlled (CNC) systems. The reconfigurable hardware provides high performance and flexibilities for the designer. This work presented a novel CNC controller architecture using reconfigurable hardware. Several logic modules, including a new resampling module for threading, are designed to support the reconfiguration process. By employing different type of logic modules, the hardware logic of the controller can be changed to control various targets. An experimental system was built, and applied to a milling machine and a lathe machine to valid the proposed architecture.

An FPGA-based low-cost VLIW floating-point processor for CNC applications

Abstract In the high-speed free-form surface machining, the real-time motion planning and interpolation is a challenging task. This paper presents the design and implementation of a dedicated processor for the interpolation task in computerized numerical control (CNC) machine tools. The jerk-limited look-ahead motion planning and interpolation algorithm has been integrated in the interpolation processor to achieve smooth motion in the high-speed machining. The processor features a compactly designed floating-point parallel computing architecture, which employs a 3-stage pipelined reduced instruction set computer (RISC) core and a very long instruction word (VLIW) floating-point arithmetic unit. A new asynchronous execution mechanism has been employed in the processor to allow multi-cycle instructions to be performed in parallel. The proposed processor has been verified on a low-cost field programmable gate array (FPGA) chip in a prototype controller. Experimental result has demonstrated the significant improvement of the computing performance with the interpolation processor in the free-form surface machining.

A new reconfigurable logic for CNC lathe controllers

Reconfigurable devices have been developed to implement the control algorithms in Computer Numerically Controlled (CNC) systems recently. Reconfigurable devices provide high execution performance of CNC and flexibilities to the system design. However, little work was done on the implementation of reconfigurable logic in a CNC lathe. This paper developed a new resampling algorithm for the synchronized movement in threading and a reconfigurable logic in a CNC lathe. An experimental system was constructed and the test results validated the proposed architecture.

Research on Reliability Design Theory and Methods of CNC System

This paper presents the methods on the structure reliability design of embedded computer numerically controlled (CNC) system. An effective reliability model is developed and tested in a real-time CNC system. The evaluation method for the importance of the reliability of each function module of CNC systems is also investigated. Fuzzy mathematics is used to judge the importance of module reliability design. Cases studies have been performed to validate and illustrate all the analysis.© 2009 ASME