Electrostatic linear servo motor with built-in position sensor for vacuum environment

Position Estimation in Singly-Fed Electrostatic Actuation Systems by Superposing Sensing Signals

“…Such built-in position sensing has been studied for some electrostatic actuation systems. One of the distinctive examples can be found in [5,6], where the slider position sensing was realized for an electrostatic linear motor. In those examples, high-frequency sensor signal was superposed on low-frequency actuation signals, which allows position sensing using the actuation electrodes.…”

A built-in displacement sensor for an electrostatic film motor

“…Positioning control is one of the most important issues for the above-mentioned applications, as well as for typical mechatronic applications. Past studies on the electrostatic motor dealt with positioning control of the motor and performed positioning servo control using builtin displacement sensors that adopted the capacitance-type linear encoder principle [13,14].…”

“…In [13], electrodes exclusively for sensor operation were additionally built on the electrode films of the motor so that the sensor operated with the classical principle of capacitance-type linear encoders. In [14], to simplify the motor structure, another sensor was developed that shared the same electrodes with motor actuation by superimposing high-frequency sensor signals onto low-frequency driving voltages. Since the motor's output performance depends on electrode area, sharing the same electrodes by actuation and sensing is a good solution for increasing electrode area, and thus improving output performance.…”

“…Although the built-in sensor using driving electrodes has been experimentally demonstrated in [14], the operation principle of the sensor was not yet revealed and its characteristics were not well studied. This paper deals with the built-in sensor to analyse its operation principle and to evaluate characteristics.…”