To ensure reliable and scalable communication among various modules in the proposed platform, a customized application-level communication protocol is developed on top of the FD-CAN layer. The system employs two independent FD-CAN channels, each configured in standard identifier mode (11-bit) and operated at a data rate of 5 Mbps using Bit Rate Switching (BRS) for enhanced throughput. Automatic retransmission and transmit pause features are enabled to improve communication reliability under time-critical control conditions.

To support modular and extensible communication, the 11-bit standard identifier is structured into three subfields: message type, source node ID, and target node ID. The message type, occupying the upper three bits of the identifier, defines the functional category of the data being transmitted. This message type is categorized into four classes: emergency (EMCY), synchronization (SYNC), Service Data Object (SDO), and Process Data Object (PDO).

This proposed communication protocol provides platform-level scalability, as new devices can be integrated by assigning respective node IDs without modifying the protocol structure. Message priority is inherently managed through the identifier field, allowing critical messages to be transmitted with higher arbitration precedence. This flexible and modular design supports seamless expansion and reliable coordination across distributed modules.

XM provides a sensor hub integration function that allows researchers to flexibly utilize a wide range of sensors depending on application requirements. Once XM and a Sensor Hub Module are physically connected, the devices automatically recognize each other, configure communication settings, and transition to normal operation without manual setup, enabling true plug-and-play functionality. This approach allows multimodal sensors such as EMG, GRF, and IMUs to be attached and used without complex configuration steps. Communication between XM and Sensor Hub Modules is supported via FD-CAN and UART protocols, allowing flexible sensor configurations and system expansion.

XM provides high-resolution data logging and real-time monitoring capabilities for research and data analysis. Data can be recorded either to a USB storage device or through a GUI application running on a connected computer via a CDC interface, with measurements acquired at a sampling period of 2 ms. The GUI supports both data logging and real-time visualization of selected signals, enabling effective monitoring of system behavior and tuning of control algorithms during experiments.