With the continuous improvement of complex and precise bending process requirements, as well as the increasing labor costs and the growing demands of workers for a better working environment, the application of fully electric bending machines with characteristics such as fast response speed, high degree of intelligence and networking, excellent control accuracy, and energy efficiency has become a development trend in the sheet metal manufacturing industry.
The development of fully electric bending machines has posed more demanding requirements for certain industries that process large-sized sheet metal parts with thicker materials and high precision. Not only do these machines need to have strong bending pressure, but they also require superior multi-axis synchronization performance. The output of high tonnage bending pressure generally requires multiple motors to synchronize and drive in parallel. Therefore, researching the servo synchronization control system and key technologies for high tonnage and high precision fully electric bending machines lays a solid foundation for the development of a new generation of fully electric bending machines with independent intellectual property rights in China.
By comprehensively analyzing market development needs and the current research status of fully electric bending machines, a general design scheme for a high-power fully electric bending machine servo synchronization control system based on the LinuxCNC 2.5 open-source CNC platform is proposed. The detailed design and research are focused on the hardware of the electrical control system, software of the CNC system, and bending control process. This scheme connects the industrial PC with the servo drives through a real-time EtherCAT bus, achieving an optimized and streamlined hardware structure. The CNC software adopts the LinuxCNC 2.5 CNC platform, which has good stability, scalability, and control performance.
Firstly, based on the analysis of the transmission structure and operation principles of fully electric bending machines, two design options are proposed. One is an embedded platform based on DSP and FPGA, forming a special CNC system dedicated to bending processes. The other is an open control system based on industrial PC and LinuxCNC 2.5, utilizing the powerful computing capability of PCs and real-time Linux operating systems to achieve stronger functionality and higher precision control. After comprehensive comparison, the latter option is selected for further design. Secondly, the selected scheme undergoes detailed hardware selection, including servo drives and motors, position detection sensors, industrial PCs, etc., and these devices are used to build a complete and stable hardware platform.
Furthermore, CNC software design and key technology research are conducted. Based on the analysis of real-time Linux systems and the LinuxCNC 2.5 architecture, the design of the EtherCAT master module, improvement of S-shaped acceleration and deceleration control algorithm, and HAL configuration for bending machine processes are implemented. Based on an in-depth analysis of the challenges in four-axis synchronization control, a synchronization drive strategy based on deviation coupling and dynamic torque control technology fusion is proposed. Prototype testing demonstrates the effectiveness and feasibility of this strategy.
Finally, a comprehensive human-machine interface and 3D graphical programming are implemented using PyQt and OpenGL technologies. The utilization of database technology and the least squares method is emphasized in designing a self-learning bending depth compensation algorithm. Prototype testing shows that the above design is practical and feasible, with satisfactory synchronization performance and processing accuracy, providing a rational, reliable, and efficient control method for high-power fully electric bending machines.
