Cycloidal Gearbox Performance Characterization Using a Testing Rig : Automated Benchmarking and Performance Analysis of Cycloidal Gearboxes

Cycloidal gearboxes combine high reduction and precision, compact form, and stiffness,making them the preferred choice for articulating robot joints. At ABB’s robotics departmentin Västerås a heavy-duty test rig was built intended to benchmark such gearboxes, but the setupwas mostly unused and lacked automation. This project converted the rig into a measurementplatform ready to use. Mechanical limitations such as vibrations and unwanted friction weremitigated, a configurable logger enabled high frequency data capture, and a Python PID loopapplied precise bidirectional torque. Repeatable protocols were established for lost motion,hysteresis, torsional stiffness, efficiency/friction, and transmission error; results are averagedover multiple cycles and angular positions to suppress noise and reveal periodic effects. Atool for analysis was developed in Python that produces plots and summary tables, allowingranking of candidate gearboxes quantitatively. Validation on a new and a 50% L10 life RotaryVector (RV) reducer showed the used unit had 20% greater lost motion, 20% lower hysteresis,13% lower stiffness, and roughly double RMS transmission error. This work turns formerlylabor-intensive testing into a fully automated process. Future upgrades should add temperaturecontrol and monitoring as well as upgrading of axis output shaft bending capabilities with loadcells and friction compensation.