Deutsches Zentrum Fur Luft-und Raumfahrt E.v.

Carl-zeiss-stiftung

Norbert Sporer

Alfons Abele

Thomas Schmid

Roland Brenner

Michael Wirth

Martin Kraus

Wolfgang Schiller

Martin Poxleitner

Hartmut Gärtner

Harald Wagner

Matthias Hähnle

In a holding arrangement () for a medical-optical instrument (), an electric motor is provided in a rotational joint () to compensate a load torque occurring in this rotational joint. This electric motor is supplied with current in correspondence to a detected position of the rotational joint (). A current control curve required for this purpose is stored in a memory. This current control curve can be determined in that the rotational joints are deflected with the electric motor into predetermined positions and the current demand needed therefor is detected.

Holding arrangement having an apparatus for balancing a load torque

A fully implantable left ventricular assist system comprising a pumping means connectable via adapter elements to the ventricle includes two compressible chambers in the form of sacs () and a compressing means () to alternatingly fill and discharge the compressible chambers () at the same time, including a drive unit () assigned thereto, a cooling means () for cooling the drive unit (), and a power supply unit () for the drive unit () and cooling means (). In this implantable system the pumping means, compression means (), drive unit () and part of the cooling means () are accommodated in a two-part housing () on which tubular ports () for connecting Y-shaped adapter elements () are configured.

Left ventricular assist system

Depending on the desired direction of current flux through an electrical load such as a stepped motor, in a measuring bridge circuit provided with switchable semiconductors and recovery diodes the semiconductors through which the current direction is switched are closed, causing the actual current to increase until it has attained the nominal current value, whereupon switching is effected into either slow current decay mode or fast current decay mode. A selection of the operating mode is made at the next semiconductor switch-on such that, if the actual current value is greater than the nominal current value at the next semiconductor switch-off, fast current decay mode is selected, and if the actual current value is lower than the nominal current value, slow current decay mode is selected. For the remainder of the chopper period, for example until the next switch-on, the operating mode is no longer changed, or switching is effected once from fast current decay mode into slow current decay mode, as a function of a comparator device that compares actual current values and nominal current values, if the actual current value is lower than the nominal current value. The invention can be used in actuation electronics for stepped motors.

Method of controlling a chopper driver and a circuit arrangement for

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Wielenbach, Germany

Norbert Sporer