Highly customizable robotic solutions for effective and safe human robot collaboration in manufacturing applications

Industrial robots have demonstrated their capacity to answer the needs of many industrial applications, offering a high degree of dexterity, accuracy and efficiency. However, when the application requires the collaboration between the robot and the worker, including workspace sharing, it is not feasible to use standard industrial robots due to safety being compromised Recently, new robotic products have appeared on the market claiming to be safe when used in the vicinity of humans, offering the possibility to control the force exerted in case of collision. However they lack the flexibility (in terms of possible physical configurations and in the ease of their programming). FourByThree proposes the development of a new generation of modular industrial robotic solutions that are suitable for efficient task execution in collaboration with humans in a safe way and are easy to use and program by the factory worker. The acronym of the project refers to the two main foci of the project: the FOUR main characteristics of FourByThree (Modularity, Safety, Usability, Efficiency) and the THREE main actors (Humans, Robots, Environment) in the manufacturing scenarios.

Duration: 01.12.2014 till 30.11.2017
Donee: German Research Center for Artificial Intelligence GmbH
Sponsor: European Union
Grant number: European Commission H2020-FoF-06-2014 Grant Agreement 637095
Partner: Fundacion TEKNIKER (Spain), DFKI RIC (Germany), Fraunhofer IFF (Germany), CNR-ITIA // CNR-ISTC (Italy), King’s College London (UK) ZEMA gGmbH (Germany), Deltatron Oy Ltd (Finland), Pilz S.L. (Spain), Antproject Tvip SL (Spain), KOMAT S.L. (Spain), EFS Gesellschaft für Hebe- und Handhabungstechnik (Germany), ALFA PRECISION CASTING, S. A. (Spain), Premium AEROTEC GmbH (Germany), WOLL MASCHINENBAU GmbH (Germany), Stodt Toekomsttechniek (Netherlands), Ground Truth Robotics GmbH (Germany)
Application Field: Logistics, Production and Consumer
Related Projects: Capio
Dual-arm exoskeleton (01.2011- 12.2013)
Behaviors for Mobile Manipulation (05.2012- 07.2016)
Cognitively enhanced robot for flexible manufacturing of metal and composite parts (10.2016- 09.2019)
Related Robots: AILA
Mobile Dual-Arm-Manipulation
Compliant Robot Arm

Project details

FourByThree will design, build and test pioneering robotic solutions able to collaborate safely and efficiently with human operators in industrial manufacturing companies.

The project responds to the demand that robots used in industry need not only to provide accuracy and efficiency, but also ensure safety when collaboration between operator and robot is required, even when the workspace is shared. Thanks to the development of innovative hardware and software, the robotic solutions proposed by FourByThree will be modular, safe, usable and efficient.

One of the objectives of the European Call is on the development of intrinsically safe robot hardware on industrial scale leading to robots which are both safe and precise. In this line, FourByThree aims to build modular industrial robotic manipulators suitable for a safe human-robot cooperation.

In this project, DFKI will provide the modular actuators and its low-level control which will serve as basis to build the robotic manipulators. These actuators are based on a recent rotary series elastic actuator design developed at DFKI which should allow intrinsically safe robot behaviour.


FourByThree: Official Presentation of the Project


Initial promotional film of the project.

September 2016

The design of a set of modular actuators has been completed. The set is comprised of four different actuator sizes (i.e. actuator torques): 28Nm, 50Nm, 120Nm, and 300Nm. All of them are equipped with embedded electronics (power electronics, communication, sensor preprocessing, FPGA-based control) and are composed of brushless DC motor, Harmonic Drive, elastic element and mechanical brake as well as the required sensors (primarily, three absolute position sensors and motor current sensors).

The design of the 28Nm actuators is based on the results from the previous project CAPIO. The 50Nm actuator was the first one which was completely designed within this project and uses a series of torsion springs as elastic element. Several of the 50Nm and 28Nm actuators have been already assembled and were used to build the first prototype robotic arms. The design of the 300Nm and 120Nm actuators has been just finalized and they are being currently manufactured. Those actuators use another principle as elastic element: a torsion bar which goes through the hollow shaft of the actuator. By doing this, the size of the 120Nm and 300Nm is quite similar and not much bigger than the previous 50Nm actuator although they include much bigger motors and provide up to six times more torque.

Prototype Arm

FourByThree: Prototype Arm

Point-to-point motion with the 2nd prototype arm

Final Review Meeting

FourByThree: project overview

Overview at the end of the project FourByThree.

FourByThree: Technologies

In this video, the main technological results of the project are presented.




Design, Modelling and Control of Novel Series-Elastic Actuators for Industrial Robots
José de Gea Fernández, Bingbin Yu, Vinzenz Bargsten, Michael Zipper, Holger Sprengel
In Actuators, MDPI, volume 9, number 1, pages 1-20, Jan/2020.


Learning the Elasticity of a Series-Elastic Actuator for Accurate Torque Control
Bingbin Yu, José de Gea Fernández, Yohannes Kassahun, Vinzenz Bargsten
Editors: Salem Benferhat, Karim Tabia, Moonis Ali
In Advances in Artificial Intelligence: From Theory to Practice: 30th International Conference on Industrial Engineering and Other Applications of Applied Intelligent Systems, IEA/AIE 2017, Arras, France, June 27-30, 2017, Proceedings, Part I, 27.6.-30.6.2017, Arras, Springer International Publishing, pages 543-552, Université Artois, Jun/2017. ISBN: 978-3-319-60042-0.


Designing Modular Series-Elastic Actuators for Safe Human-Robot Collaboration in Industrial Settings
José de Gea Fernández, Holger Sprengel, Martin Mallwitz, Michael Zipper, Bingbin Yu, Vinzenz Bargsten
In International Conference on Climbing and Walking Robots and Support Technologies for Mobile Machines, (CLAWAR-16), 12.9.-14.9.2016, London, CLAWAR, Sep/2016.
FourByThree: Imagine humans and robots working hand in hand
Iñaki Maurtua, Nicola Pedrocchi, Andrea Orlandini, José de Gea Fernández, Christian Vogel, Aaron Geenen, Kaspar Althoefer, Ali Shafti
In Proceedings of the 21st IEEE International Conference EFTA, (ETFA-2016), 06.9.-09.9.2016, Berlin, n.n., Sep/2016.
EU Projekt FourByThree: Auf dem Weg zu eigensicheren Robotern
José de Gea Fernández, Marc Ronthaler
In Industrie 4.0 Management, Gito mbH Verlag für Industrielle Informationstechnik und Organisation, volume o.A., pages o.A., Apr/2016.

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