Tim Rossner

Performance of a novel micro force vector sensor and outlook into its biomedical applications

For the HapCath system, which provides haptic feedback of the forces acting on a guide wires tip during vascular catheterization, very small piezoresistive force sensors of 200•200•640μm3 have been developed. This paper focuses on the characterization of the measurement performance and on possible new applications. Besides the determination of the dynamic measurement performance, special focus is put onto the results of the 3- component force vector calibration. This article addresses special advantageous characteristics of the sensor, but also the limits of applicability will be addressed. As for the special characteristics of the sensor, the second part of the article demonstrates new applications which can be opened up with the novel force sensor, like automatic navigation of medical or biological instruments without impacting surrounding tissue, surface roughness evaluation in biomedical systems, needle insertion with tactile or higher level feedback, or even building tactile hairs for artificial organisms.

Examples of Haptic System Development

In this section, several examples of task-specific haptic systems are given. They give an insight into the process of defining haptic interactions for a given purpose and illustrate the development and evaluation process outlined in this book so far. Examples were chosen by the editors to cover different basic system structures. Section 14.1—Tactile You-Are-Here-Maps illustrates the usage of a tactile display in an assistive manner, enabling a more autonomous movement of people with visual impairments. Section 14.2—User Interface for Automotive Applications presents the development of a haptic interface for a new kind of user interaction in a car. It incorporates touch input and is able to simulate different key characteristics for intuitive haptic feedback. Section 14.3—HapCath describes a comanipulation system to provide additional haptic feedback in cardiovascular interventions. The feedback is intended to reduce exposure for both patient and physician and to permit new kinds of diagnosis during an intervention.

Miniaturized Haptic User-Interface for Heart Catheterizations – Concept and Design

During heart catheterization the cardiologist controls the direction of the guide wire mainly by visual x-ray information. In this paper a haptic display is presented, which generates an amplified force feedback of the contact force measured at the distal tip of a guide wire. A network model is elaborated and a concept for miniaturization and integration into a haemostasis valve is proposed.

B4.3 - Investigations of the electrical contacting of new piezoresistive polymer-ceramics

Silicon oxycarbide nanocomposite with segregated carbon (C/SiOC) belongs to the group of polymer derived ceramics (PDCs). The C/SiOC shows piezoresistive properties by mechanical load. As an advantage over metal foil strain gauges and doped sensing resistors, the C/SiOC material is expected to have a high gauge-factor (k-factor) even for high temperature applications. In order to characterize the piezoresistive properties of the C/SiOC material, force-impedance characteristic must be acequired. The paper will show different layouts of the electrical contacts and different resistance measurement by using four-terminal and two-terminal sensing. The measurement results will be compared to each other and be discussed.