Hideo Muro

An algorithm for distinguishing the types of objects on the road using laser radar and vision

Describes a method for distinguishing the types of forward objects detected on and alongside the road using a vehicle-mounted scanning laser radar (SLR) and a camera. This method can measure the distance to a preceding vehicle in the same lane as well as to other forward vehicles in adjacent lanes. Objects are detected on the basis of SLR digital signal data and are categorized as vehicles, delineators, and signs based on their motion and positions relative to white lane markers. The motions of detected objects are judged by the relationship between the path of the host vehicle and changes in the positions of the objects. The host vehicles path is computed using steering maneuver data and the vehicle velocity. White lane markers are detected by an image processing technique. The proposed algorithm has been validated in an experiment conducted with a simulator. Data recorded at a driving speed of more than 40 km/h on Japanese expressways were used in the simulation. The types of objects detected on the road were successfully distinguished as expected.

Integration of two degree-of-freedom magnetostrictive actuation and piezoresistive detection: application to a two-dimensional optical scanner

A novel two-dimensional (2-D) optical-scanner device is presented. This device incorporates a highly magnetostrictive thin film with anisotropic properties, so that it can produce 2-D-actuation corresponding to bending and torsion vibrations. The magnetostrictive material is a TbFe-CoFe multilayer film, which has optimized properties for micro-actuators operating at low excitation magnetic fields. The new scanner also integrates an original 2-D piezoresistive detector realized in an easy fabrication process using integrated circuit (IC)-compatible technology. The detectors are able to selectively measure bending and torsional vibrations. This new device enables the synchronization of actuation and sensing for 2-D position control.

Application of a multilayered magnetostrictive film to a micromachined 2-D optical scanner

A novel two-dimensional (2-D) optical scanner has been designed, manufactured and characterized. This scanner features a large mirror (8/spl times/6 mm) and is therefore suitable for industrial applications where cheap optical sources and lenses are requested. This scanner uses a multilayer film for its actuation. This film is well known for its high magnetostriction. The mechanical design has been optimized using conventional mechanical considerations as well as finite-element simulations. The device has been characterized in two configurations. Depending on the direction of the applied magnetic field, the magnetostrictive properties of the active film or the electromagnetic force are selectively used. Using this last, total optical deflection angles of 32/spl deg/ and 11/spl deg/ for an applied magnetic field of 0.3 mT are obtained. The ratio of the corresponding resonant frequencies is around 4.5, allowing a nice scanning pattern. Compared to our previous prototype on the same project , the mechanical-magnetic sensitivity has been improved by about a factor 24 when the magnetostriction is used, and by about a factor 75 when the electromagnetic force is used.

Magnetostrictive-ring type torque sensor using two Hall ICs with differential magnetic field detection

A novel magnetostrictive-ring type torque sensor has been developed which used a new detection scheme for detecting the differential magnetic field and signal conditioning circuitry with the temperature drift compensation. Torque of a shaft was measured by detecting the leakage magnetic field emanating from the magnetostrictive-ring made of permendur Fe49Co49V2 which was attached to the stainless shaft. The magnetic sensor was constructed using a pair of commercial Hall ICs and a permalloy magnetic yoke embedded onto the circuit board. The temperature offset adjustment was accomplished by adding only four diodes and resistors to differential amplifiers. The measured sensitivity was 45 mV/Nm for the applied torque range from -4 Nm to +4 Nm.

A Novel Optical Scanner with Integrated Two-Dimensional Magnetostrictive Actuation and Two-Dimensional Piezoresistive Detection

A novel two-dimensional (2D) optical-scanner device is presented. This device incorporates a highly magnetostrictive thin film with anisotropic properties so that it can produce 2D-actuation corresponding to bending and torsion vibrations [1–2]. The magnetostrictive material is a TbFe/CoFe multilayer film [3–4], which has optimized properties for micro-actuators operating at low excitation magnetic fields. The new scanner also integrates an original 2D piezoresistive detector realized in an easy fabrication process using IC-compatible technology. The detectors are able to selectively measure bending and torsional vibrations. This new device enables the synchronization of actuation and sensing for 2D position control. It could be used in a laser-radar system for obstacle detection in automobiles.

History and Recent Progress of MEMS Physical Sensors

Recently various electronic control systems for automotive, industrial and consumer-electronic applications have been developed using advanced semiconductor technologies including MEMS sensors. This paper reviews the history of the development of the MEMS physical sensors and highlights their recent progress where their research trends are categorized into the following 4 items:ⅰ) Incorporation of heterogeneous sensors,ⅱ) Integration with advanced CMOS circuitry,ⅲ) Improvement on wafer-level packaging technology, ⅳ) Adoption of new materials. Several examples of each item are introduced in this paper.