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Flexible pneumatic actuators

New industrial and medical applications require micro-actuators with a high force and power density. During the last decades, it was believed that electrostatic and electromagnetic microactuators would fulfill these needs. However, recent research revealed that hydraulic microactuators develop higher power and force densities at microscale. The micro-and precision engineering group of PMA investigates new actuator configurations and new production and assembly techniques that allow reducing the crosssection of these actuators down to 1 mm² or less.

A wide variety of hydraulic microsystems was successfully developed throughout the last years. These systems range from medical tools to general purpose micro-actuators, from classic piston-type actuators to elastic artificial muscles and from microvalves and micropumps to peripheral technologies such as microfluidic interconnections. 


The current trend towards miniaturization, portability and more in general ubiquitous intelligence has created the need for high-power density portable power sources. Despite advances in battery technology, the energy density of most fuel types is still 100 times higher than for the best batteries.

The aim of this research is to develop an ultra-miniature gasturbine, approximately the size of a large coffee mug, with an electrical power output in the range of 1 kW. The system basically consists of a compressor, recuperator, combustion chamber, turbine and electrical generator, all with miniature dimensions. A major challenge is the high rotational speed of 500,000 rpm, required to generate sufficient pressure with a compressor only 20 mm in diameter. Special air bearings are used that offer stability at these extreme speeds. To cope with temperatures up to 930 ºC and extreme centrifugal forces, the turbine is made from a ceramic composite (Si N -TiN). Hydrogen is 3 4 used as fuel due to its wide combustion limits, fast combustion speed, and clean exhaust gasses. 


Prof. dr. ir. Dominiek Reynaerts
Tel: +32 16 32 26 40

Prof. dr. ir. Sylvie Castagne
Tel. +32 16 37 74 23

Industrial research contact
Dr. ir.  Jun Qian 
Tel: +32 16 32 25 24

KU Leuven
Department of Mechanical Engineering, division PMA
Celestijnenlaan 300 - box 2420
3001 Heverlee, Belgium