High Performance Actuators

Electrical actuators with high performances are more and more requested in specific fields like aeronautics, automotive, and spatial or medical applications. In these fields, requirements in terms of reliability, encumbrance, and consumption are particularly critical.

Opting for electromechanical conversion for these applications is due to the significant progresses achieved in power electronics, and microelectronics. Therefore actuators can be powered as a function of their loading and real-time controlled through complex control strategies. Moreover, specific tools to achieve reliable modeling and simulation help in customizing the design for each specific application.

Different principles of electromechanical conversion co-exist: electromagnetic, piezoelectric, etc… Therefore designing high performance actuators requires a multidisciplinary approach, combining all aspects of the problem (consequences of choosing a particular technology, related control approaches …) at each step of the design process (from prototyping to final design).

Actuators for aeronautical applications

Details: Written by Paul Sente

Electromechanical converters engineering has evolved continuously during the last decades due to availability of :
• new materials, notably rare-earth magnets for affordable prices;
• more and more performing software tools for field calculation and optimization.
The activities in this domain concern essentially the design of high performances actuators for a wide range of areas : going from aerospace (in cooperation with industrial partners working in the field) to robotics and medical applications.
For the aeronautic industry, a study has been recently carried out for estimating the possibility to install electric generators in a civil aircraft engine nacelle. Other studies, conducted in the field of European projects, concernes the the design and the control of electrical actuators used in thrust vector control, direct drive servovalves, steering systems.

It is clear that power electronic converters play an important role in such mechatronic systems as they act as interface between the control, an electrical energy source and the controlled mechatronic system. But this is the subject of another theme among our research projects.

Electromechanical modeling of the dynamical behavior of magnetic bearings subjected to induced currents

Details: Written by virginie kluyskens

Magnetic bearings can prove to be useful in various situations, like high-speed or vacuum applications where classical roller bearings reach their limits.

However, in any kind of magnetic bearings, eddy currents may play a significant role. Eddy currents in magnetic bearings can be undergone negatively because they generate losses and unpredicted forces. When not taken into account, this may even lead to a malfunction of the magnetic bearing; But eddy currents in magnetic bearings may also be used positively, to generate desired forces, like in electrodynamic bearings. However, these latter are very difficult to design.

This is why a dynamical model for the eddy current forces in electrodynamic magnetic bearings, but also in all kind of magnetic bearings and even electric machines, is important. This model has to integrate the mechanical aspects linked to the rotor dynamics and the electromagnetic nature of the forces.