Bioinspired Flexible Capacitive Sensor for Robot Positioning in Unstructured Environments

Abstract

The evolution of bionic machines into intelligent robots to adapt to real scenarios is inseparable from positioning sensors. However, traditional positioning methods such as camera arrays, ultrasound, or GPS are limited in narrow concealed spaces, harsh temperatures, or dynamic light fields, which hinder the practical application of special robots. Here, we report a flexible sensor inspired by Gnathonemus petersii that enables robots to achieve contactless and high-precision spatial localization independent of the unstructured features of the environment. Sensors are obtained from lowcost materials (carbon nanotubes and polyimides) and simple structures (fibers) and preparation processes (spin-coating). Experiments and simulations confirmed the high resolution (<1 mm) of the sensor over a large distance detection range (>150 mm) and high bandwidth (0−520 MPa) of contact force. Moreover, the sensing capability is still feasible when the sensor is bent to various curvatures and not affected under harsh conditions such as ultralow temperatures (below −78 °C), ultrahigh temperatures (over 250 °C), darkness, or brightness. We demonstrate the practical potential of the proposed sensors for a biomimetic hyperredundant continuum robot to locate and avoid collisions in unstructured environments.

A flexible precontact CNT-Al2O3 fiber sensor resistant to extreme temperatures

“…Inspired by the capacitance variation of capacitors and other nanomaterial-based fiber sensors, 7,29,30 we designed a spatial precontact sensor based on the fiber's structure (Fig. S1†).…”

“…This type of sensor can detect the spatial position 27 and motion trajectory 28 of objects by measuring the capacitance reduction generated by the change in edge electric field, and can be applied to the field of robot obstacle avoidance. 29 We also examined the flexibility of the fiber and the stability of the sensor through experiments. It is worth emphasizing that due to the excellent physical and chemical properties of CNTFs, as well as the temperature stability and flame retardancy of the Al 2 O 3 coating, the sensor can realize long-distance spatial position perception and exhibit ultra-high stability over a wide temperature range of −78 °C to 500 °C.…”