Plain polymer bearings help bring humanoid robot to life

RoboThespian is a life-sized humanoid robot designed for human interaction in a public place. Being fully interactive, multilingual and user-friendly, it offers a new and memorable way to communicate and entertain. Users can set it up for inspirational educational, business or theatrical performances simply by writing their own scripts; these can be elevated to truly spectacular shows with multiple RoboThespians working together.

RoboThespian was designed by Engineered Arts, a specialist in the design and build of imaginative, interactive exhibitions, audio visual and mixed media installations, and a company that now enjoys a worldwide reputation as a developer of full-size humanoid robots for communications, research and entertainment.

Robothespian was originally intended for use in science and technology centres as an entertaining vehicle for content delivery. Among its leading-edge features are motion capture, object recognition and telepresence. There are now more than forty of them installed in fourteen countries around the world. Simple to operate and maintain, they are trusted as front-of-house hosts by national science centres, including NASA’s Kennedy Space Center, a variety of visitor attractions, commercial users and academic research institutions.

The 2013 manus UK award from polymer bearing specialist, igus recognises the company’s innovative use of polymer bearings – specifically its iglidur range of bearings - on all of Robothespian’s rotating shafts, which has enabled its gestures to be more fluid and friction-free, conveying convincing and human-like movements.

RoboThespian has over 26 axes, powered with a mixture of pneumatic and servo actuators. During its development Engineered Arts established some key design criteria, including smooth, human-like movements in all axes. High reliability and easy serviceability were also deemed essential because of the high-profile nature of its deployments around the world.

These issues have been successfully addressed - and with the bonus of a significant reduction in weight - through the use of maintenance-free iglidur J and iglidur G polymer bearings on all rotational shafts. iglidur J bearings are characterised most notably by their extremely low coefficients of friction in dry operation and very low stick-slip effect. iglidur G bearings are suitable for high loads and low speeds.

A total of 85 iglidur bearings are used to help ease movement throughout the body of the robot, from head to toe. The low friction, small size and lightweight iglidur bearings complement the anodised aerospace grade aluminium components used throughout RoboThespian; they form the basis for the smooth, human-like movements and gesturing plainly evident whenever the robot is fired up for action. Engineered Arts design and production engineer, Marcus Hold summarises:

“We have a great relationship with the people at igus and receive a first-class service from them. The products are of excellent quality and are reliable which is of the utmost importance to us, as our humanoid robots are required to perform daily without fail in busy public environments. The impact of the iglidur bearings on RoboThespian’s performance is just as important – without igus, he wouldn’t be able to move in the smooth way he does today.”