Traditional subterranean propagation whether for utility infrastructure, mining, or environmental monitoring often relies on heavy, energy-intensive machinery that removes soil to create space. These methods are frequently destructive, difficult to scale down for precision applications (like biomedical surgery), and struggle in heterogeneous or granular environments. There is a critical market need for minimally invasive, energy-efficient, and steerable digging tools.

The Innovation
Researchers at Tel Aviv University have developed a first-of-its-kind hybrid soft-stiff robot inspired by the female desert locust (Schistocerca gregaria). Unlike most animals that dig by removing material, the locust creates a burrow by radially compacting soil against the surrounding walls.

Key Technical Features:
Bio-Replicated Ovipositor: 3D-printed digging valves modeled via $\mu$CT scans to replicate the exact morphology of the locust’s digging tip.
Hybrid Architecture: Combines a rigid digging head with a soft, fiber-reinforced pneumatic “abdomen” that can elongate up to 1.6x its original length.
3D Kinematic Coordination: Implements a complex 4-degree-of-freedom sequence: Protraction $\rightarrow$ Opening $\rightarrow$ Retraction $\rightarrow$ Closing.
Adaptive Steering: A flexible silicone body capable of bending and twisting to navigate around underground obstacles.

Figure 1. Female-locust-inspired robot design. a) The abdomen of the female locust, with the inset highlighting the ovipositor. b) Female locust valves were scanned using μCT, processed and transformed into a computer-aided design model. This model was integrated into the robotic design and fabricated using 3D printing. c) The robot components and structure. d) The mechanical functions of the robotic flexible body and rigid ovipositor during digging motions (Video S2, Supporting Information; cf. Figure 1d).

Performance & Efficiency Results
The study utilized the robot to quantify the energetic advantage of the locust’s natural digging pattern compared to alternative mechanical strategies.

Figure 2. Robot operation and motion. a) The paths of the locust’s digging valves. Black -dorsal valves, red – ventral valves. b) Imitation of the paths of the locust’s digging valves simulated by the robot. c) The paths of the locust’s digging valves by the robot, utilizing the full valve opening range. d) The locustinspired robot during operation and propagation in an environment of glass beads. Scale bar corresponds to 10 cm (Video S4, Supporting Information).

Critical Findings:
Energy Optimization: Deviating from the biological trajectory increases energy costs by up to 2.4-fold.
Substrate Versatility: The system demonstrated high efficiency in both controlled glass beads and heterogeneous garden soil, outperforming traditional “single-spike” insertion methods.
Mechanical Leverage: The locust’s trajectory minimizes the force required for initial soil penetration while maximizing the compaction force at the end of the stroke.

Commercial Applications
This technology offers a scalable blueprint for a new generation of autonomous underground tools:
Utility Infrastructure: Micro-tunnelling for fiber optics, water, and gas with minimal surface disruption.
Space Exploration: Low-mass, high-efficiency regolith burrowing for planetary missions.
Environmental Monitoring: Non-destructive soil sampling and sensor deployment.
Medical Robotics: Steerable, flexible probes for minimally invasive surgical procedures in soft tissues.