Capacitive servo-device for microrobotic applications

The authors have performed a preliminary study of the servo-properties of a single-unit configuration of the linear rotary differential capacitance (LRDC) transducer. Although it was initially used only for angle sensing, recent experiments demonstrated an actuator function of the LRDC device. In the present work, both the sense and the drive functions have been simultaneously activated in a feedback network. Force control around 3*10-8 N has been accomplished with macro-sized (2-5 cm plate diameter) units. Previously demonstrated scaling properties predict that a micro-unit of similar design (size about 100 mu m) would have excellent sensitivity and respond at high speed. Thus the device is expected to find use as the principal component of a microrobot.