One of the greatest challenges facing the developers of the humanoid robot, iCub, was the creation of motion systems that combine high performance, low weight and small size. For this expertise, researchers have sought the help of Kaydon whose bearing technology has been providing these qualities in medical device technology and aerospace applications for many years.
iCub is a project financed by the European Union and based at the Robotics, Brain and Cognitive Sciences and iCub Facility departments at the Italian Institute of Technology in Genoa. It is an international venture to which many research establishments continue to contribute including the Universities of Hertford, Salford and Sheffield.
iCub came into being to further research into artificial cognitive systems. The robot is capable of physically interacting with humans and researchers are also working to give the iCub complete independence. A recent development has been RoboSKIN which equips the surfaces of the robot with sensors so it can perceive contact with its environment, control interactive forces and avoid damage to itself and others. iCub is now also able to see and hear.
Its application scope is huge. In the industrial environment, for example, iCub can be used as an assistant; domestic use is also a possibility. It houses 53 motors in total, of which 32 are in its hands and arms, allowing movements such as holding and delicate manipulation of objects.
Kaydon became actively involved in the project when it started supplying its REALI-SLIM thin section bearings through its Italian partner, Milan-based Magi Srl. These bearings enable the rotation of various parts that make up the robot’s joints and keep it upright.
At the same time, the joint axes are kept in the correct alignment despite the exertion of tangential forces, which normally tends to deform the axis and/or other rotating components. As some parts rotate at speeds of several thousand revolutions per minute absolute precision is imperative in order to prevent the entire mechanism seizing up. In some applications it has also been necessary to protect the moving parts from excessive loading.
The REALI-SLIM that is commonly used in iCub is a four-point bearing with small diameter, generally 25.4mm or 50.8mm (1 or 2 inches). Compared with conventional radial bearings, the REALI-SLIM bearings are more rigid and can absorb higher radial, axial and torque loads; for applications that require even greater rigidity, pre-stressed bearings are supplied.
Professor Giorgio Metta, who co-directs the project in Genoa with Professor Giulio Sandini, explains: “The project demanded low-friction, highly compact bearings that were able to sustain high radial and axial loads in two directions for the robot’s joints. Based on these requirements, the researchers rejected slide bearings and self-lubricating bushes, opting instead for the REALI-SLIM series by Kaydon.”
In the UK, Ireland, Scandinavia and Turkey Kaydon REALI-SLIM bearings are available exclusively from R. A. Rodriguez. For further details please go to www.rarodriguez.co.uk.