Takeshi Fujimura

Miniaturization of a V-Shape Transducer Ultrasonic Motor

The miniaturization of a V-shaped transducer ultrasonic motor (VSM) was carried out. The head block design and nut length were optimized to match resonance frequencies without coupling asymmetric and spurious vibrations. The volume of the new miniaturized VSM was 58% of that of the original VSM. The speed, thrust, and resolution of the new VSM compared favorably with those of the original VSM. A massive ceramics linear stage was driven by the new VSM working in the sole-use VSM feedback control system. For a traveling distance of 20 mm, the stage motion was controlled to remain in the target position plus or minus 1 nm within 350 ms.

Improvement of the low speed controllability of a V-shaped, two bolt-clamped Langevin-type transducer, ultrasonic linear motor

A V-shaped, two bolt-clamped Langevin-type transducer, ultrasonic linear motor VSM was developed. In this study, the low speed controllability of the VSM was improved by the development of a new driving principle in which a feedback control was applied. The speed of the VSM was more than 1500mm/sec and the velocity error was approximately 0.2% when driven at 1000mm/sec. Ten nm step driving also could be obtained, and lnm resolution was observed. In the combination of a fast mode and a micro-motion mode, the stage was settled to a target position of plusmnlnm.

A high voltage power supply utilizing a ceramic transformer with a large output current

The article describes a high voltage power supply utilizing a ceramic transformer with the capability of supplying about 1 mA at an output voltage of 4 kV. The power supply delivers a large output current, spanning a high voltage at output, with the efficiency of more than 80%. The ceramic transformer is newly developed for the power supply. The power supply includes feedback to stabilize the output voltage ranging from 2000 V to 4000 V with a load of more than 4 MOmega at the efficiency of about 80%. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. The transformer is free of leakage of magnetic flux. So the high voltage power supply can be operated under a strong magnetic field