MedTec
Two-dimensional scanner for medical devices
Besides having high drive dynamics for precise positioning, this drive unit had to meet a set of further stringent requirements: minimal volume and form factor, a small accelerated mass of no more than 1.5 grams, direct drive and battery operation. Specifically, for each scanning point a distance of 0.5mm had to be covered within 5ms and +/- 35µm accuracy. A customized software-algorithm was developed to reach each target position at maximal acceleration without overshooting. This design required very light parts and the bearings had to be backlash-free with minimal friction.
Gas-sampling
In this sampling device, a precise volume of gas had to be acquired quickly for a volume and time sensitive analysis. The low total energy consumption of the drive was essential for this battery-operated device. Analysers of this type can thus be designed more flexibly and economically with the Elliptecmotor and use less power than comparable portable units.
Autonomous navigation assistant for MRI guided interventions
MRI would be the preferred guidance device due to the fact that it provides the best soft tissue contrast and comes with no or little negative side effects for the human body. Known problems have to be overcome while working in or around an MRI system, mainly related to the strong magnetic and electric fields, which require the use of special materials and special shielding.
The Elliptec Motor is used which provides acceptable torque and speed for our application and which works also in the strong magnetic field. The slide system residing in the MRI magnet drives on a belt system following the curvature of the bore. For the desired range and tilting of a laser pointer 4 Elliptec Motors were used for the movement along the curvature and another two Elliptec Motors for the conical movement. With the laser pointer integrated a total height of slightly less than 7cm was achieved. The rotational wheels attached to the piezoelectric drive systems were coded and allowed for accurate positioning.
The device shows that it is possible to create an inexpensive MRI compatibe navigator device with piezoelectric motors, whose height can be reduced to 5cm and the number of motors can be reduced with further weight reductions of the slide. The device could be used inside the magnet bore of the MRI, as well as for CT interventions.
