Giving robots a human name has been nothing unusual since the advent of cobots - in many cases, it helps to reduce the workers' fear of contact with their new 'colleagues'. In the case of the robot from the Constance-based company Fruitcore Robotics, the name 'Horst' may well contribute to this - in this case, however, the name of the 6-axis robot is simply an abbreviation for 'highly optimized robotic systems technology'.

Horst pursues a novel kinematic approach. The second and third main axes are driven by so-called four-bar linkages (VK). This means that movement and power are not transmitted directly to the robot axes by means of a drive unit - usually an electric motor and gearbox - as is usually the case, but indirectly via the four-bar linkages. This means that the drive shafts and the actual robot axis are not in the same position.

The four-bar link chains are arranged in such a way that, according to Fruitcore, they enable a high power transmission when the position of the robot requires it and the transmission ratio becomes smaller when the power is not required. The mode of operation of a four-bar chain can be seen by comparing it with gear drives: in a four-bar chain, the crank of the VK corresponds to the small gear wheel and the swing arm to the large gear wheel. The coupler connects the crank and swing arm. If the crank rotates uniformly, a non-linear rotary movement occurs on the swing arm. This means that the swing arm moves faster in some places than in others. The transmission of forces behaves in the same way. If the swing arm moves slowly (high gear ratio), more power is transmitted - if the swing arm moves faster (low gear ratio), less power is transmitted. Due to this operating principle, the transmission ratio of four-bar chains is not linear, in contrast to gear drives.
In addition, the rods of the four-bar link chains transfer some of the forces to the structure, which means high system rigidity combined with low mass. Because this mass does not have to be moved, Fruitcore says that the power of the drives can be used more efficiently and, overall, high performance data in terms of load capacity, range and dynamics can be achieved with Horst with comparatively small drives.

Set up in 30 minutes

Horst's four-bar link chains are arranged in such a way that they enable a high power transmission when the position of the robot requires it, and the transmission ratio becomes smaller when the power is not required.

© Fruitcore

The robot is programmed using the horstFX software, which was specially developed for the 13.3-inch touchscreen supplied. The latter is also used to operate Horst. Fruitcore promises that users can set up and program it intuitively and without specialist knowledge in less than 30 minutes via a graphical user interface.

Connected components such as grippers and external machines are easily controlled via the graphical programming using the interfaces commonly used in the industry or via digital inputs/outputs. However, the software can be operated offline and away from the robot, for example on desktop computers. No programming knowledge is required for this. Graphically generated programs can be automatically converted into textual codes or into the JavaScript-based scripting language horstScript. With this fully-fledged robot programming language, all process parameters can also be configured and advanced users can use it to solve even highly complex programming tasks.

The graphical user interface has an intuitive design and is reminiscent of the operation of a smartphone. Programs can be created either live or by means of simulation. Once programs have been created, users can edit them at any time and move or delete individual blocks. It is also possible to import data for additional tools and 3D objects.

Without coding to the program

With a footprint of 380 mm x 380 mm, the compact industrial robot is very easy to integrate into processes.

© Fruitcore

Horst also has a proprietary bus system with differential signals. The company has created its own mainboard for central control. The control system is based on a fast processor that controls the six axis joints in real time. Optical incremental encoders are used to ensure high positioning accuracy in the range of ±0.05 mm. All safety-relevant signals are evaluated and processed redundantly in accordance with performance level d (PL d). In addition, the in-house developed safety controller offers safe inputs and outputs for communication with safety systems such as light barriers or safety scanners.

According to the manufacturer, the investment costs for Horst are well below 20,000 euros, which should enable small and medium-sized companies in particular to make a simple and manageable entry into automation. The robot system can handle payloads of up to 5 kg and has a reach of 900 mm with a footprint of 380 mm x 380 mm. Horst's big brother is already being worked on in Constance. This will be able to handle even heavier loads and have a greater reach.

Potential applications for the robot include loading and unloading machines, stacking, sorting and packing products, handling turned, milled and punched parts, as well as pick & place applications.