CNC machining is developing towards high speed and high efficiency. This includes the speed control of CNC machining. To make full use of the effective working stroke, it is necessary to accelerate the moving parts to a high-speed stroke in a very short time, and to stop accurately during the high-speed stroke. This is why the speed control of CNC machining is necessary.
According to the open control idea, we propose a method that can automatically accelerate and decelerate the movement of CNC machine tools according to arbitrary curves. This method pushes the automatic acceleration and deceleration control from the traditional fixed mode to a new flexible mode, and explores a new way to effectively improve the dynamic performance of CNC machine tools.
1. Flexible acceleration and deceleration control
In CNC machining, the specific automatic speed control function is generally directly realized by the system program. In this way, it is necessary to change the acceleration and deceleration characteristics of the system or to modify the NC program through the addition and subtraction control, so ordinary users cannot make the CNC machine tool have the best acceleration and deceleration performance according to their own wishes. Therefore, the flexible acceleration and deceleration control method we proposed adopts the principle of database, divides the acceleration and deceleration control into two parts: acceleration and deceleration description and implementation, and separates the acceleration and deceleration description from the system program. In the numerical control system software, a common control channel is designed that has nothing to do with the content of the acceleration and deceleration database, and it independently completes the calculation of acceleration and deceleration and trajectory control.
2. Flexible automatic acceleration control
Set the acceleration curve, analytical curve and non-analytic curve, and store them as a template in the acceleration and deceleration curve library in the form of a number table.
3. Flexible automatic deceleration control
It is also stored in the acceleration and deceleration curve library as a template in the form of a number table for acceleration control. Reasonable automatic acceleration and deceleration control is an important link to ensure the dynamic performance of CNC machine tools.