The robust, energy-efficient climbing robot SpaceClimber is designed for missions in challenging territory. Essential parts of its structural system are the intelligent, powerful joints. mayr® power transmission have developed a mini brake especially designed for such a joint. It impresses users with its small dimensions and increases the robot’s energy efficiency. This robot system is being further developed at the German Research Centre for Artificial Intelligence (Deutsches Forschungszentrum für Künstliche Intelligenz, DFKI).
In future, the intention is for it to explore planets independently and be able to set up an infrastructure using its gripping arms – the new multi-arm walking robot that is currently being developed by scientists at the Robotics Innovation Center at the German Research Centre for Artificial Intelligence (DFKI). The robot, which resembles a praying mantis, has been created within the context of the LIMES project, which is to continue until the end of April 2016 and which is supported by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR). Thanks to its morphology and the different walking patterns for different soil conditions, it will be capable to cope with craters and boulder fields and manipulate these with its front legs. By learning from its experiences, it will be able to act in a targeted manner. With its locations in Kaiserslautern, Saarbrucken, Bremen and Berlin, the German Research Centre for Artificial Intelligence (DFKI) is the largest research centre for artificial intelligence worldwide.
Role model: The ant
An already tried-and-tested space robot by the DFKI and one of the predecessors of the LIMES project is the climbing robot SpaceClimber. In its morphology, it resembles its natural role model – the ant. The SpaceClimber is a free-climbing robot with six legs, designed for missions in challenging territory, for example for the exploration of crater walls, crevices or gorges. In its basic posture, the robot is approximately 80 cm wide, one meter long and 20 cm high. It weighs approximately 25 kg. The SpaceClimber reliably masters steep, asymmetric slopes with angles of up to 80 percent, and moves at a speed of 0.3 m/s. Among the most important components promoting the immense mobility of the robot are the drives for its structural system. Therefore, intelligent, light-weight, high-performance joints with a focus on energy efficiency have been developed.
There is also a joint in the upper body of the robot: If the SpaceClimber walks into an inclined wall, e.g. into a crater, the upper body can adapt to the surroundings and straighten up or fold down on the crater edge. Furthermore, the upper body can also straighten up, for example, to free the front legs for manipulation. An extremely compact ROBA-stop® safety brake is installed in this joint, which mayr® power transmission has developed especially for this application. When the SpaceClimber walks with its upper body horizontal across an even surface, the brake reliably holds the joint in position and prevents the input and output from turning when the motor is switched off. “Using this brake, the joint need not be energised permanently to hold the position, and this saves energy“, says the DFKI Project Manager, Dr.-Ing. Sebastian Bartsch. The brake has a holding torque of 0.28 Nm and only weighs 120 grammes with an outer diameter of 40.5 mm. “For us, the small dimensions of the brake was the decisive criterion”, says Dr.-Ing. Sebastian Bartsch. “We only had limited installation space to accommodate the brake without changing the design or increasing the weight substantially”. Safety brakes by mayr® power transmission work according to the fail-safe principle, which means they are closed in de-energised condition. The brakes generate the braking force through thrust springs. After current switch-off or in case of power failure, they guarantee reliable and safe holding of the device in any position.
The robot lady AILA
The mini brake has also already been used in the robot system AILA, a mobile, autonomous system with two arms. “In AILA, the brake was installed in the elbow joint”, explains Dr.-Ing. Sebastian Bartsch. “When the robot takes something in its hand, it is necessary to generate energy permanently to keep the arm and the item elevated. Using the brake, the motor can be switched off, thereby saving energy”. AILA is able to sort and handle individually heterogeneous items which vary considerably in their form and characteristics, for example different articles in a supermarket. With the aid of the object information stored in the digital memory, she is able to adapt her gripping and transportation behaviour to the specific characteristics of the respective items.
Tried-and-tested safety brakes
For more than 40 years, mayr® power transmission have developed and manufactured spring applied safety brakes; they are the global market leaders in the fields of elevator brakes, stage equipment and vertical axes. The company also has the expertise required to develop tailored and economical solutions for customer-specific requirements, for example for medical engineering or robot applications. Safety brakes by mayr® power transmission have already proven their high level of reliability million-fold in field applications. Tried-and-tested design principles and permanent inspections on calibrated test stands guarantee consistently high levels of quality.
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