Dual-Channel EtherCAT Control System for 33-DOF Humanoid Robot TOCABI

Multi-axis actuation robotics systems comprising many joints with a floating base require more stability and safety than fixed robots and thus require more considerations. In this paper, we describe the implementation of a real-time EtherCAT control system for the TOCABI humanoid robot with 33 degrees of freedom (DOFs) is described. The focus is on the development of a high-performing EtherCAT MainDevice, which enables control of the robot's high DOF at fast communication cycles. We also explore the use of a dual-channel EtherCAT MainDevice as a redundancy mechanism to handle communication disruptions and show that this configuration reduces the burden on the communication network and increases the communication cycle, leading to good real-time performance. To demonstrate the advantages of the system, we examine the performance of the EtherCAT communication and evaluate the impact of RTnet on real-time performance, demonstrating that a high-performing EtherCAT MainDevice having hard real-time capabilities can be established using open-source software. The results of this work demonstrate the potential of using dual channels in EtherCAT MainDevice configurations and utilizing open-source software to implement low-cost EtherCAT MainDevice systems. The paper's contribution to the field is its indication of developing stable robot systems with high DOF, which require hard real-time capability, even with open-source software.