How to Select the Right Robot Joint Actuator: A Practical Engineering Guide

TL;DR: A step-by-step framework for engineers selecting robotic joint actuators — covering torque requirements, transmission type, communication protocol, and control interface. Includes downloadable spec comparison template.

The Problem: Too Many Options, Too Little Guidance

If you're building a robot arm, cobot, or humanoid and searching for actuators, you've probably noticed:

Some suppliers list peak torque, others list continuous torque

"Backdrivability" means different things to different manufacturers

Communication protocols range from CANopen to EtherCAT to RS485, with no universal standard

Price varies by 10x for seemingly similar specs

This guide gives you the decision framework I wish someone had given me when I started.

Step 1: Define Your Torque Requirements

The single most common mistake is using peak torque for sizing.…