Morphological Modulation Enables Adaptive Locomotion in Symmetric Impulse-Driven Robots

Abstract

Impulse-driven limbless robots offer a promising platform for locomotion in environments where body deformation or complex actuation is undesirable. Prior work has shown that symmetric designs can achieve net displacement through temporally asymmetric internal actuation, yet such systems often exhibit limited adaptability due to weak coupling with environmental parameters. By introducing geometric curvature into the robot's chassis, we show that a minimal morphological modification can enrich the locomotion dynamics of impulse-driven robots with a symmetric body. Through dynamic modeling and simulation, we demonstrate that curvature strengthens the interaction between internal impulses and ground contact, allowing the robot's speed to respond to environmental friction. Experimental validation supports that actuation-dependent trends align closely with simulation predictions, and an omnidirectional extension further highlights the design's scalability. Our findings suggest that even in simple robotic systems, small morphological changes can significantly enhance performance by shaping how internal actuation couples with environmental interaction. This work advances the understanding of embodied symmetry-breaking and offers a low-complexity pathway toward adaptable and agile robotic locomotion.