Design of a bioinspired robophysical antenna for insect-scale tactile perception and navigation

The American cockroach (Periplaneta americana) uses its soft antennae to guide decision making by extracting rich tactile information from tens of thousands of distributed mechanosensors. Although tactile sensors enable robust, autonomous perception and navigation in natural systems, replicating these capabilities in insect-scale robots remains challenging due to stringent size, weight, and power constraints that limit existing sensor technologies. To overcome these limitations, we introduce CITRAS (Cockroach Inspired Tactile Robotic Antenna Sensor), a bioinspired, multi-segmented, compliant laminate sensor with embedded capacitive angle sensors. CITRAS is compact (73.7x15.6x2.1 mm), lightweight (491 mg), and low-power (32 mW), enabling seamless integration with miniature robotic platforms. The segmented compliant structure passively bends in response to environmental stimuli, achieving accurate hinge angle measurements with maximum errors of just 0.79 degree (quasistatic bending) and 3.58 degree (dynamic bending). Experimental evaluations demonstrate CITRAS' multifunctional tactile perception capabilities: predicting base-to-tip distances with 7.75 % error, estimating environmental gap widths with 6.73 % error, and distinguishing surface textures through differential sensor response. The future integration of this bioinspired tactile antenna in insect-scale robots addresses critical sensing gaps, promising enhanced autonomous exploration, obstacle avoidance, and environmental mapping in complex, confined environments.

mCLARI: a shape-morphing insect-scale robot capable of omnidirectional terrain-adaptive locomotion in laterally confined spaces

Soft compliant microrobots have the potential to deliver significant societal impact when deployed in applications such as search and rescue. In this research we present mCLARI, a body compliant quadrupedal microrobot of 20mm neutral body length and 0.97g, improving on its larger predecessor, CLARI. This robot has four independently actuated leg modules with 2 degrees of freedom, each driven by piezoelectric actuators. The legs are interconnected in a closed kinematic chain via passive body joints, enabling passive body compliance for shape adaptation to external constraints. Despite scaling its larger predecessor down to 60 percent in length and 38 percent in mass, mCLARI maintains 80 percent of the actuation power to achieve high agility. Additionally, we demonstrate the new capability of passively shape-morphing mCLARI - omnidirectional laterally confined locomotion - and experimentally quantify its running performance achieving a new unconstrained top speed of 3 bodylengths/s (60 mms-1). Leveraging passive body compliance, mCLARI can navigate through narrow spaces with a body compression ratio of up to 1.5x the neutral body shape.