Eberhard Bamberg

Velocity Control with Gravity Compensation for Magnetic Helical Microswimmers

Magnetic helical microswimmers, which swim using a method inspired by the propulsion of bacterial flagella, are promising for use as untethered micromanipulators and as medical microrobots. Man-made devices are typically heavier than their fluid environment and consequently sink due to their own weight. To date, methods to compensate for gravitational effects have been ad hoc. In this paper, we present an open-loop algorithm for velocity control with gravity compensation for magnetic helical microswimmers that enables a human operator or automated controller to command desired velocity intuitively, rather than directly controlling the microswimmers orientation and rotation speed. We provide experimental verification of the method.

Fabrication of 3-dimensional silicon microelectrode arrays using micro electro discharge machining for neural applications

Ultra high aspect ratio microelectrodes are designed and fabricated to record and stimulate neural signals from deeper areas of the brain and nerves and also to provide a new research tool to the neuroscience community. We present a fabrication process to build ultra high aspect ratio silicon based microelectrode arrays for the neural applications. The µ-wire electrical discharge machining (µ-WEDM) process enables machining electrodes from highly conductive bulk silicon. The electrodes are electrically isolated near their base by glass. Thin, needleshaped and smooth silicon microelectrodes are realized with an optimized chemical etching process.

Optical system to detect volume of medical samples in labeled test tubes

A novel system for liquid-level detection is reported. The system uses two different wavelengths of light to detect the liquid level of medical samples in tubes that are covered by an unknown number of paper labels. By measuring the intensity of the transmitted light at two distinct wavelengths and computing their ratio, which is compared to a threshold value, a system was developed that is self-compensating for the number of tube labels and the type of medical sample to be analyzed. A laboratory prototype was built, and the test results were analyzed using different types of medical samples. Based on a series of experiments, the system was found to detect the liquid level of 0.4 mL with a maximum allowable tolerance of ±0.1 mL with better than 99.73% reliability and a total test time of 0.5 s. These results were achieved with test tubes that had up to six layers of labels attached to the outside of the tube, thereby making the tube completely opaque.

Concrete-based Constrained Layer Damping

This paper describes a novel structural damping method that allows a fabricated (welded) machine tool structure to be designed for minimum cost and maximum dynamic stiffness comparable to polymer concrete structures. The damping method is a constrained layer damping (CLD) design where the layers are replicated in place using expanding concrete inside of viscoelastic damping inserts. The novel design is highly flexible and economical while providing excellent damping for a wide range of structural shapes.

Rapid Prototyping of Full Scale House Structures

This paper reports on the machining of a construction material (aerated concrete) with a rapid prototyping device, Shapemaker III, which is based on waterjet technology. Preliminary machining tests were carried out to investigate machining conditions (speed and pressure) of separation cuts. Cutting speeds for the waterjet were investigated for two aerated concrete construction materials; autoclaved aerated concrete (AAC) in two strengths (348 and 580 psi compressive strength) and a non-autoclaved, fiber reinforced aerated concrete (FRAC) with a 450 psi compressive strength. Cutting samples were prepared in four thicknesses (0.5, 1, 2, and 3 inches) and cut at two pressures (40 and 60 ksi). The 0.5 and 1 inch specimens were cut with good surface finish at over 600 in/min at 40 ksi. The 2 and 3 inch specimens could be cut at 320 and 80 in/min at 40 ksi, respectively. The experimental data was used in the fabrication of rapid prototyping houses with a pure waterjet machine. As results, full scale houses were fabricated with FRAC and Styrofoam. Additionally, a sub-mold of an outdoor fireplace was manufactured with Styrofoam for casting of customized aerated concrete blocks.Copyright