The design helps you build motor control systems for humanoid robot joints faster by simplifying power and signal connectivity.
Molex has released a Major Joint Motor Control Reference Design to help engineers develop power and signal connectivity for humanoid robot joints. The reference design includes a block diagram, schematic, bill of materials (BOM), and Fusion design files, providing a starting point for designing motor control systems used in major joints such as the shoulders, hips, and knees.
The reference design targets one of the most demanding areas of a humanoid robot. Major joint motors require high-current power distribution and fast switching to achieve accurate position and torque control. These operating conditions create challenges related to power integrity, thermal management, and connector reliability, particularly in compact robotic architectures.
To address these challenges, the design uses Mini-Fit Sr. Connectors for high-current power connections. The connectors feature terminals rated up to 50A, secure locking mechanisms, and stable contact interfaces to maintain consistent power delivery to motor drives, braking circuits, and sensing systems. Secure retention also helps prevent connector disengagement in applications exposed to continuous motion and vibration.
The reference design also incorporates Micro-Lock Plus Connectors for lower-power signal connections. Available in 4-, 6-, and 16-circuit configurations with a 1.25 mm pitch, these connectors include positive locking features that help maintain reliable electrical connections while reducing the risk of incorrect mating during assembly. Their compact footprint supports the dense PCB layouts commonly found in humanoid robot joint controllers.
Beyond component selection, the reference design provides engineers with complete hardware resources, including the system block diagram, detailed schematic, bill of materials, and Fusion design files. These resources can be used as a foundation for developing custom motor control electronics while reducing design effort and integration time.
As humanoid robots continue to adopt more powerful actuators and compact electronic architectures, reliable interconnects become critical for maintaining stable power delivery and control signals. By combining high-current and signal connector solutions within a validated reference design, Molex aims to help engineers accelerate the development of robust joint motor control systems for next-generation humanoid robots.
The reference design can also serve as a learning platform for engineers developing new actuator systems. By studying the connectivity approach, engineers can better understand how to separate high-current and signal paths, improve power integrity, and select connector systems that support reliable operation in dynamic environments. These insights are particularly useful during prototype development, where design iterations are frequent and integration challenges are common. To read more about this reference design, click here.
