In the era of the Internet of Things (IoT) and Industry 4.0, intralogistics plays an increasingly important role. The precise transport of materials and goods becomes an essential factor for efficient production. Evocortex’s mobile transport systems accomplish this task by unusual means. The power density of the FAULHABER motors used is also decisive for the realization of their creative technical concept.
Today the term “production” has become synonymous with “complexity”. Products are increasingly manufactured according to individual customer specifications; with an IoT connection, fully automated production is possible even with batches of just one unit size. Such a multitude of variants requires processes that are closely intertwined and, at the same time, very flexible. The right parts and components – in an almost infinite number of variations – must be ready at the individual production stations at the right time.
Advanced AMR
The transport of material, for example between supply points and production facilities, is becoming more and more individual and at the same time should take place in the most automated way possible. Mobile robotic platforms – known in the industry as autonomous mobile robots (AMRs) – are therefore increasingly numerous in warehouses and production halls around the world.
The Nuremberg startup Evocortex, founded in 2016 with the participation of robot experts, focuses on this market. Closely associated with the nearby Technical University of Nuremberg and other educational and research institutes, the company entered the market with a completely new AMR concept. With its products, it offers creative and innovative solutions for the needs of modern intralogistics.
“Conventional AMR often needs spatial adjustments to routes or even to make
technical changes to processes “, explains CEO Hubert Bauer. “For example, optical markings are needed so that vehicles can orient themselves; the paths and intersections must match the specified dimensions and radii of curvature. We, on the other hand, wanted to create a transport robot that would adapt to the customer’s needs and not vice versa “.
The “fingerprint” of the house floor indicates the exact location
Evocortex autonomous mobile robots (AMRs) do not require any pre-installed guidance system to recognize their position and find the right path. They are simply based on the unevenness of the shed floor. These irregularities can also be found on common smooth concrete floors and are recorded by the robot’s high resolution camera. The camera is located at the bottom of the vehicle, covers an area of 10 x 10 centimeters and uses the image data to create the equivalent of a fingerprint of the shed floor. Behind this ingenious system is the Localization Module (ELM) developed by Evocortex.
During the initial learning process, the robot walks across the shed floor in a grid pattern. With the help of complex algorithms, a high-precision map is created from a pattern of individual points. In the future, this will also be possible through self-learning thanks to the use of artificial intelligence. In addition, the control detects the vehicle’s own movement.
By combining the data, it can position the vehicle over a theoretical area of one square kilometer with millimeter accuracy. For this purpose, three points identified are sufficient. Even though 50% of the floor is covered with sawdust, the ELM remains indifferent and guarantees robust, precise and accurate navigation. New permanent scratches in the
floor are added to the map, while items that have disappeared are removed after a
some time.
The AMRs can optionally be equipped with additional LIDAR sensors on one or two fronts. These scan the area in the direction of travel and recognize obstacles, including those in motion such as people crossing the path. The vehicle then stops immediately to ensure employee safety.
Unlimited mobility with Mecanum wheels
A normal wheel only moves in the same direction as its axis. In order to accurately position a vehicle with such wheels, it is necessary to maneuver in the same way as when parking a car. To avoid this, the Evocortex developers opted for the Mecanum wheel. Instead of a closed running surface, domed rollers are mounted on its rim. They are fixed at an angle of 45 degrees to the wheel axis and can rotate around their own oblique support axis. The shape, size and distance of the rollers are selected to give the wheel a continuous rolling surface.
When the Mecanum wheel turns, two force components are created, one in the direction of rotation of the entire wheel and the other perpendicular to it. The resulting direction of movement lies in the middle: the Mecanum wheel “wants” to move at an angle of 45 degrees with respect to the direction of the axis. However, due to the mobility of the rollers, it has no directional stiffness. When other forces are applied, the movement can be deflected in any direction.
On a Mecanum four-wheeled vehicle, the 45 degree angles are offset by 90 degrees each. Each wheel therefore faces a different direction. By varying the direction and speed of rotation of each individual wheel, it is possible to steer the vehicle in any direction from a standstill or rotate it on the spot. On the horizontal plane, it can therefore move freely like a hovercraft. The Mecanum wheels therefore allow the robot to move in an agile and omnidirectional way.
Scalability millimeter by millimeter
Evocortex AMRs offer an additional dimension of flexibility: they can be produced in a virtually unlimited number of sizes. “If necessary, we can adapt our robot millimeter by millimeter to the needs of our customers,” Hubert Bauer points out. “Between 400 by 480 and 800 by 1200 millimeters, all external dimensions are achievable”. In the case of the EvoRobot R&D and EvoRobot Industrial product lines, these dimensions also roughly correspond to the external dimensions of the support platform. All the technology – sensors, controls, lifting units and wheel drives – is mounted under the platform.
The wheel drive module is a decisive element for this scalability. Located directly above each wheel, it forms a standardized and independent functional unit with it. The wheels can therefore be mounted at any distance from each other. The decisive prerequisite for this arrangement is a powerful engine of a very small size.
“We looked very closely at which motors on the market could be suitable for this type of application”, remembers Hubert Bauer about the development phase. “Only with FAULHABER did we find the power density we needed. Competitor engines would have required more space for the required torque ”.
Huge power, minimal size
The EvoRobot wheel modules are equipped with 3257… CR or 3272… CR series DC motors. Each has an IEF3 encoder and a 38/2 S gearbox. The wheel motors also feature a brake for quick stop and to ensure that the wheels remain locked in position when stationary. “Thanks to the enormous power of these micromotors, the EvoRobot is capable of handling up to 200 kilograms and soon even larger loads”, Spiega Huber Bauer. “The transport also works on a ramp inclined by five degrees and at a speed of one meter per second.”
The EvoCarrier product line is designed for the transport of containers for small parts. Inside this AMR, space is even more limited than in the EvoRobot. The robot is less than 100mm high. This then allows it to move in extremely low openings under the transported goods. Two or four EvoCarriers can also work together to transport pallets or an entire rack.
For the drive, the developers chose a so-called “flat rotor motor” – a brushless motor from the 4221 BXT series with a length of only 21 millimeters. The EvoCarrier can therefore carry stacks of small containers
pieces (KLT) on wheels weighing up to 120 kilograms in total. The CEO believes that, in the long term, the EvoRobot will also likely switch to brushless motors and that module standardization will continue.
In addition to the power / volume ratio, the absence of maintenance and reliability in continuous service play a particularly important role in the operation of the AGV. “With FAULHABER motors, our life span requirements are more than met”, adds Hubert Bauer. “Furthermore, the fact that the drives work with all common industrial controls is also an advantage. The FAULHABER experts were also very helpful in finding the optimal parameter setting for series production ”.