Spare Parts and Repairs

The parts most likely to need replacing

On a robot that walks and handles objects, the parts at the edges have the hardest life: fingers and grippers, foot soles, outer covers and the cables that cross moving joints. A fall during testing can crack a cover, knock a camera out of alignment or strain an actuator. Ask each maker which parts it expects to replace most often, how many of each it suggests keeping on site, and the price and lead time for each. A 2019 study by the European Commission's Joint Research Centre on scoring repair and upgrade calls these priority parts, chosen by how often they fail and how important they are to the product, which is a useful way to frame the request.

Judging repairability before you buy

Repairability is fixed at the design stage, so check it before you order. The Joint Research Centre study combines pass or fail criteria with a score based on design features that affect repair, and you can borrow its logic: ask how many steps it takes to reach each priority part, whether standard tools will do, and whether the maker publishes repair guides and diagnostic software. ISO 22166-1:2021 sets requirements for designing service robots from integrated modules, so ask whether the robot follows a modular design and which modules can be exchanged on site. A robot built from sealed sub-assemblies may need to travel back to the factory for work a modular one would allow locally.

Who carries out the repair

Agree in advance which repairs your own staff may do, which need a local service partner and which mean shipping the robot back. For the first group, ask the maker for training, a parts list and written confirmation that doing those repairs yourself leaves the warranty intact. For the second, ask where the nearest authorised technician is based and how quickly they can reach you. For the third, get a typical turnaround time and the packing instructions. Ask whether remote diagnostics can narrow down a fault before anyone travels, which avoids a wasted visit. Keep a simple repair log for each unit, since a pattern of the same fault is the strongest case for a design fix.

Keeping spares available for years

Humanoid designs are changing quickly, and a part for this year's model may not fit next year's. Ask the maker how many years it will supply parts after a model is discontinued, and whether that promise appears in the contract. Check whether replacement parts must be paired to the robot by the maker's software, because pairing can block a local repair even when you hold the part. If you run several units, standardise on one model and software version where you can, so a single spares kit covers the fleet. Review your spares stock after each repair and reorder before the shelf is empty, especially for parts with long lead times.

Sources and further reading

• Analysis and development of a scoring system for repair and upgrade of products — European Commission Joint Research Centre.
  JRC method for rating repairability through priority parts, pass or fail criteria and a design-based score.
• ISO 22166-1:2021 Robotics – Modularity for service robots – Part 1: General requirements — International Organization for Standardization.
  Requirements for building service robots from integrated modules, a basis for asking what can be swapped on site.

Common questions

What should I do if a humanoid falls over?

Stop it, make the area safe and inspect it before restarting, looking for cracked covers, loose cables and joints that move unevenly. Record the fall and send the logs to the maker, since a single fall can damage parts that only fail later.

Are 3D-printed parts safe to use on a humanoid?

For covers and brackets they can be a practical stopgap, but anything carrying load, holding a battery or forming part of a safety function should come from the maker. Ask before fitting printed parts, because they may affect the warranty and the robot's conformity.