K2 Center for Symbiotic Mechatronics

In contrast to compact and light weight highly integrated electro-hydraulic drives for distributed actuation classical centralized drive and supply systems often lead to strong restrictions in machine design and modularization because the distribution of centrally generated power/movement in a mechanical or hydraulic manner complicates the design and strongly reduces the potential for light weight structures needed, e.g., in robotics or exoskeletons and machine tools. Additionally, in such applications purely electric drives often reach their limits in terms of compliance and realization of additional features like adjustable damping. In many of such cases the combination of electrical with hydraulic drives can give excellent answers (Habib14). Thus, objective 2 will address compact and light weight drives for distributed actuation.

Such drives will replace more and more classical centralized drive and supply systems and will provide the outstanding advantages of both, electric and hydraulic drives like high power density, adaptable flexibility and damping (especially needed for exoskeleton drives). State of the art in electro-hydraulic actuation is mainly defined by robotics, aviation and automotive. But most of them are application tailored solutions not feasible for industrial use, or in a very early development state (Leati16). To achieve such an outstanding efficiency and power to weight ratio for a wide range of applications such drives have to show an extraordinary tight system integration of electrical and hydraulic components and power electronics. New approaches in system integration like pump integration into the rotor of the electric motor or high frequency oscillation approaches what will result in the development of new topologies of the electrical parts and the use of alternative lightweight materials like polymers and compound materials for the pump housing and check valves will be addressed. As a result power densities of more than 200W/kg at efficiencies of 80% and beyond are tackled. To this end, complicated loss phenomenon in hydraulic components shall be analysed by elasto-hydrodynamic modelling combined with optimization methods (SyMSpace) to find solutions for a strong loss reduction and high component lifetime and of much higher dynamical performance check valves will be addressed.

In addition, such highly integrated and distributed drive concepts need also embedded sensors and electronics as well as predictive maintenance or condition awareness capabilities. The corresponding research will be done in connection with the following topic.

Possible content (subject to be refined during project):
• Joint workshop on hydraulic systems in exoskeletons.
• Identification and investigation of possible methods for integrating highly compact drive systems in exoskeletons
• Identification of further project financing (EU, national)
• Joint publication