Alexander Nothhelfer

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Research on surgical robotics demands systems for evaluating scientific approaches. Such systems can be divided into dedicated and versatile systems. Dedicated systems are designed for a single surgical task or technique, whereas versatile systems are designed to be expandable and useful in multiple surgical applications. Versatile systems are often based(More)
PURPOSE Many publications describe the use of diffusion-weighted imaging (DWI) in breast MRI. This article addresses the question of when to apply the DWI sequence in the course of the scan protocol. The effect of T1-shortening contrast media (CM) on the ADC values of breast lesions is investigated. MATERIALS AND METHODS Data were acquired on a 1.5 T(More)
An anthropomorphic hand arm system using variable stiffness actuation has been developed at DLR. It is aimed to reach its human archetype regarding size, weight and performance. The main focus of our development is put on robustness, dynamic performance and dexterity. Therefore, a paradigm change from impedance controlled, but mechanically stiff joints to(More)
A two-step procedure for the microdetermination of cholesterol in serum lipoproteins is compared with cholesterol quantitation after density gradient ultracentrifugation. Serum lipoproteins from 10 mul of serum are separated by electrophoresis on agarose and visualized by precipitation with dextran sulfate--CaCl2. The lipoprotein bands are cut off from the(More)
The paper presents a new torque-controlled lightweight robot for medical procedures developed at the Institute of Robotics and Mechatronics of the German Aerospace Center. Based on the experiences in lightweight robotics and anthropomorphic robotic hands, a small robot arm with 7 axis and torque-controlled joints tailored to surgical procedures has been(More)
Robotic surgery systems are highly complex and expensive pieces of equipment. Demands for lower cost of care can be met if these systems are employable in a flexible manner for a large variety of procedures. To protect the initial investment the capabilities of a robotic system need to be expandable as new tasks arise.
The computing and communication architecture of the DLR Hand Arm System is presented. Its task is to operate the robot's 52 motors and 430 sensors. Despite that complexity, the main design goal for it is to create a flexible architecture that enables high-performance feedback control with cycles beyond 1kHz. Flexibility is achieved through a hierarchical(More)
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