Hidenori Sekiguchi

Impulse Radio UWB Positioning System

We developed a positioning system using impulse radio UWB. The system consists of tags equipped only with transmitters and nodes provided with both transmitters and receivers. The system calculates the position of the tags using the TDOA method, whereby some nodes receive the UWB pulses sent from a tag. The tag is operated with a coin battery, and sends UWB pulses intermittently. The node sends the receiving time data to a PC via an Ethernet network for position calculation. We developed a time clock correction method, which is also required for the TDOA method. We will further evaluate positioning accuracy etc. in the future

Development of an Isolation Table with an Active Vibration Control Mechanism.

Isolation tables are effective in preventing vibration. If objects on a table move, however, the table starts vibrating at a low frequency, with a large displacement due to the force of the impact. Some equipment on an isolation table cannot be kept at a constant distance from equipment on the ground. To overcome this problem, An active vibration control mechanism based on state feedback control using 4 voice-coil motors was developed. This system could suppress the displacement of the isolation table at 100 μm even if some objects on the table moved.