Indirect rotor position detection method based on angular admittance modulation of optimally designed piezoelectric ultrasonic motors

Ultraminiature Angular Position Sensor Based on the Beta-Voltaic Principle

“…The angular position sensors that are based on electromagnetic techniques [1]- [3] typically have dimensions on the order of several centimeters, since they usually depend on transformer action for sensing. Angular position sensors that use optical encoding techniques [4], [5] have dimensions in the order of tens of millimeters.…”

“…Unfortunately, all the angular position sensors that are available commercially at the present time are quite large and cannot be used in such applications (see in-depth analysis in the Appendix). Angular position sensing technology includes electromagnetic techniques [1]- [3], optical encoder techniques [4], [5], Hall effect techniques [6]- [8], and variable capacitance techniques [9]- [14]. The last two families of techniques are suitable for MEMS applications; however, since the sensing element is usually a Hall effect sensor or a variable air capacitor, the sensitivity of such sensors is typically reduced at MEMS scales.…”

“…This component has a diameter of 8 mm and a thickness of 0.5 mm. 3 The β-particle source has a thickness of ∼0.2 mm. Additional details about the procedure that was followed in Fig.…”