NURBS direct interpolation method and device with processing characteristics considered

Abstract

The invention provides an NURBS direct interpolation method and device with processing characteristics considered. According to the method, an equation with multiple constraint conditions is established with machine tool kinematics, dynamic characteristics and tool path working conditions considered, pre-interpolation processing is completed, and a feed speed sequence is obtained; an off-line speed planning module searches for and determines an overproof area of tangential acceleration, and readjustment is carried out on the overproof area by adopting an S-shaped acceleration / deceleration mode; real-time interpolation is carried out on each interpolation period through the adjusted speed sequence, the interpolation device enables the position information of interpolation points to pass through a servo controller and drives a servo motor to complete real-time on-line interpolation through a dynamic link library technology. According to the NURBS direct interpolation method and device with the processing characteristics considered, the multiple constraint conditions such as single axial acceleration limit, Jerk limit and curvature characteristics are made to be met by the interpolation, the machining efficiency under the small curvature condition is improved, the capacity of coordination control over machining quality and machining efficiency is further improved, and machine tool vibration or system vibration can be avoided effectively.

Description

technical field [0001] The invention belongs to the technical field of numerical control machining, and in particular relates to a NURBS direct interpolation method and device considering machining characteristics. Background technique [0002] Numerical control technology is one of the most critical links in modern manufacturing technology. High-speed, high-precision numerical control machining systems play an important role in national economic development and national defense construction. At present, when the traditional CNC system processes parts with complex shapes, it generally first discretizes the machining path of the tool into a large number of straight line segments, and then performs linear interpolation processing on the parts. This processing method is difficult to guarantee the processing speed and processing accuracy. Machine tools are prone to shock and chatter, which directly affect the processing quality and efficiency of parts. NURBS (Non-Uniform Ration...

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Problems solved by technology

The main problems existing in NURBS curve interpolation at this stage are concentrated in the following aspects: the existing interpolation algorithms rarely consider the characteristics of the machine tool drive system, or focus on the control of the synthetic speed and acceleration curves, the kinematics of the feed axis The limitation of the component and the jerk have not been included in the interpolation constraints, and the stability of the motion during the machining process cannot be well guaranteed; in addition, the lack of consideration of the geometric characteristics of the tool path is good for both high efficiency and high precision. There are still some deficiencies in matching, and the ability of comprehensive coordination and control needs to be strengthened

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