Five-axis machine tool speed planning method based on S-shaped acceleration and deceleration

Abstract

The invention discloses a five-axis machine tool speed planning method based on S-shaped acceleration and deceleration. The method comprises the steps: obtaining the path information of a continuous machining path, and building a complete S-shaped acceleration and deceleration model; dividing an incomplete acceleration and deceleration process into a plurality of conditions, and establishing a corresponding acceleration and deceleration speed diagram planning method; then correcting the limiting speed of the starting point of the small line segment; determining acceleration and deceleration types which should be adopted by the current small line segments through the S-shaped acceleration and deceleration classification model, calculating displacement, speed and acceleration diagrams of the small line segments, and solving coordinate values of each axis under a workpiece coordinate system through linear interpolation; and finally, converting the coordinate value of each axis in each interpolation period in a workpiece coordinate system into the coordinate value of each axis in each interpolation period in a machine tool coordinate system by adopting reverse coordinate transformation, performing part processing, calculating the velocity diagram of each small line segment forwards segment by segment, and finally obtaining the interpolation instruction position and instruction speed on the whole processing path. High feeding speed can be achieved, and moving stability of moving parts of a machine tool is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of interpolation methods of high-speed numerical control technology, and in particular relates to a five-axis machine tool speed planning method based on S-shaped acceleration and deceleration. Background technique [0002] Acceleration and deceleration control is an important part and one of the key technologies of the CNC system. During the motion control process of the CNC system, it plays an important role in ensuring the smooth movement of the moving parts of the machine tool, reducing the vibration during machine tool processing, and ensuring the processing quality of parts. effect. [0003] The relatively simple and commonly used acceleration and deceleration control methods mainly include linear and exponential acceleration and deceleration methods. The linear acceleration and deceleration method is easy to implement. In the exponential acceleration and deceleration method, the feed speed is acceler...

AI Technical Summary

Problems solved by technology

In the related research of flexible acceleration and deceleration, it mainly includes: (1) The construction method of S-curve acceleration and deceleration is given by numerical method or analytical method, but when faced with high-speed, high-precision and high-curvature machining, the discrete small line segment is relatively short (2) By simplifying the S-curve acceleration and deceleration model to a 5-stage S-curve acceleration and deceleration model, the complexity of the model can be reduced. Although it can meet the requirements of flexible speed changes, it is not suitable for uniform acceleration and deceleration. Acceleration section can only reach the maximum feed rate

(3) Speed ​​control is carried out by using flexible acceleration and deceleration with jerk gradient to achieve continuous jerk, but the complexity of the method is increased and the real-time performance is poor. At the same time, the maximum jerk of the machine tool cannot be effectively used in the form of jerk gradient, resulting in The increased acceleration and deceleration time of the machine tool is not conducive to the improvement of the machining efficiency of the machine tool

In addition, the above research work still has the following deficiencies: in the actual acceleration and deceleration control, due to the short length of some line segments, the actual speed of the end point of the line segment obtained is greater than the limit speed of the end point, and it will be at the end point of the current line segment, that is, It is the starting point of the next line segment that produces a sudden change in speed, which seriously affects the surface quality of the part.

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