When it comes to robotic joints, engineers have had to put together complex custom configurations out of multiple components, which involved considerable development time with the mechanisms. This time requirement often reduced the amount of time artificial-intelligence programmers had with the system. So, two goals of robotics developers were to enable the programmers to be involved with the process earlier and develop a straightforward modular system. The realization of these goals is closer, thanks to a recently introduced innovative robot joint module system from igus. The company is currently looking for beta testers for this new product.
The robot unit, known as Robolink, was primarily designed for robot developers and laboratories that work with humanoid systems, as well as with lightweight engineering systems for handling and automation. The design was inspired by Dr. Rudolf Bannasch, Managing Director at the Berlin-based company EvoLogics, a high-tech company working in the field of bionics and humanoid robots. He provided both the motivation and developmental support behind this Robolink component.
It consists of a drive-and-control unit, joints in different lengths, and arms in different sizes, including a duct for additional control cables. The jointed arms are made from carbon fiber reinforced plastic and other lightweight materials. At the end of the jointed system is the option to connect to different types of tools.
The drive-and-control unit was purposely designed as a black box. Robot developers have the option to work with pneumatics, electro technology, or hydraulics.
The bionic core of the robot’s skeletal parts is the injection-molded plastic joints. They are controlled through cable pulls that transfer tensile forces, similar to the way tendons function in humans. The cable sheath is held and the inner cable moved. This way, the gripper, shovel, hook—or whichever tool the developer chooses—is moved and operated.
All data cables are routed safely through the jointed arms. The cable pulls are routed through from one joint to the next—just as joints are connected in humans. Only four cables are required for each plastic joint to rotate and swivel freely. These cables convey images, acoustics and forces, which are the artificial senses of humanoid robots.
The cables themselves are made from technical synthetic fibers. The fibers are extremely strong, hardly stretch at all, are resistant to chemicals, and are lubrication-free and wear resistant. When compared to steel, their lighter weight also makes them much more energy efficient.
Since the system is modular, it can be constructed with all kinds of humanoid robot configurations. This ranges from jointed arms, moving ‘digger’ arms, through to four-legged ‘creatures.’ The joints can be easily combined as required.
igus’ development objective was to keep the moving mass as low as possible, so that the actuators can be separated from functioning tools, such as grippers, hands, suction cups, and so on. Particular attention was given to enable quick assembly, as well as the use of tribo-optimized plastics to reduce lubrication needs and weight.