Robot Multi-Axis Synchronous Motion Control Based on EtherCAT
With the development of industrial automation, the application of robots on production lines is becoming increasingly widespread. To achieve efficient and precise motion control, the multi-axis motion of robots must be capable of synchronized operation, which enhances the motion accuracy and stability of robots, leading to more efficient production line operations. Additionally, it provides a foundation for collaborative work and control among robots, allowing multiple robots to coordinate their movements simultaneously to complete more complex tasks. The real-time deterministic Ethernet protocol based on EtherCAT offers a feasible solution for this.
EtherCAT is a high-performance, real-time industrial Ethernet communication protocol that enables fast data transmission and synchronized operations among multiple nodes. In robot multi-axis motion control systems, the EtherCAT protocol can be used to transmit commands and reference values between control nodes, ensuring that they are synchronized with a common clock, thereby enabling synchronized operations in the multi-axis motion control system. This synchronization has two aspects. First, the transmission of commands and reference values between control nodes must be synchronized with a common clock; second, the execution of control algorithms and feedback functions must also be synchronized with the same clock. The first type of synchronization has been well understood and has become an inherent part of network controllers. However, the second type of synchronization has been overlooked in the past and is now becoming a bottleneck for motion control performance.Specifically, the EtherCAT-based robot multi-axis synchronous motion control method includes synchronization in two key aspects: the synchronization of command and reference value transmission, and the synchronization of control algorithm execution and feedback functionality.In terms of command and reference value transmission synchronization, commands and reference values are transmitted between control nodes through the EtherCAT network. These commands and reference values need to be synchronized under the control of a common clock to ensure that each node performs motion control according to the same time step. The EtherCAT protocol provides high-speed data transmission and synchronization mechanisms, ensuring that the transmission of commands and reference values is highly accurate and real-time.
Meanwhile, in terms of the synchronization of control algorithm execution and feedback functionality, each control node needs to execute control algorithms and feedback functions according to the same clock. This ensures that each node performs calculations at the same time point, thereby achieving synchronized control of multi-axis motion. This synchronization requires support at both the hardware and software levels to ensure that the execution of control nodes is highly accurate and real-time.The following multi-axis synchronization test video demonstrates that the actuator integrates 1) high-precision reducers, 2) high-performance brushless motors, and 3) high-resolution absolute encoders, allowing for the design of high-precision industrial-grade robotic systems suitable for various applications.In summary, the EtherCAT-based robot multi-axis synchronous motion control method realizes the synchronization of command and reference value transmission as well as the synchronization of control algorithm execution and feedback functionality through the support of real-time deterministic Ethernet protocols. This method provides a reliable solution for multi-axis motion control in robots and brings new opportunities and challenges to the development of the industrial automation field.
