Stacked electrostatic angle sensor implemented in micro robot leg joints

Recently, micro walking robots have attracted considerable research interest, as they can move robustly in various terrains and are especially useful in swarm applications. To realize angle control for the robots, external sensors such as rotary encoders were attached to joints. When assembling external sensors and joint components, careful handling and positioning are needed. However, robots requiring intricate assembly of multiple components are not optimal for the above-mentioned applications. We proposed the integration of robot frames and capacitive angle sensors to one compliant sheet. Moreover, a stacked electrostatic angle sensor was developed by alternately folding two ribbon electrodes. The angle was estimated from the capacitance based on the distance between the electrodes. The sensor was designed and fabricated. Furthermore, we constructed the angle feedback control system using the proposed sensor. Feedback control within the range of 0° to 30° could be realized.