Multifunctional Locomotion Control of Multi-Jointed BURs with Swimming and gait Capabilities

2026-09-29

AI Summary

This study addresses the limitations of traditional rule-based control in acquiring novel behaviors and the difficulty of achieving multimodal locomotion with a single mechanical structure. To overcome these challenges, this work proposes a nonlinear control method based on potential functions. By integrating multi-joint mechanisms, potential function control algorithms, and multisensory technologies, the approach enables a four-legged fin structure to autonomously switch between swimming and walking gaits. This framework eliminates reliance on predefined rules, facilitating the emergence and nonlinear transition of multimodal behaviors within a unified mechanical architecture. Both simulation and physical experiments demonstrate that the system successfully achieves smooth transitions between multiple locomotion modes, significantly enhancing environmental adaptability for underwater exploration.

Abstract

Multimodal biomimetic underwater robots (BURs) can conduct underwater tasks suitable for the environment. Combining the characteristics of aquatic organisms enables the swimming and leggedlocomotion required for underwater exploration. Locomotion control mechanism relies on rule-based behavior selection and the designer's discretion. This limits the robot's ability to acquire new behavioral capabilities to the predetermined range of behaviors. To address these challenges, we propose a mechanism and control system that enables the expression of multimodal locomotion capabilities from the same multi-jointed structure. A mechanism equipped with four leg-fins each having four axes is used. This controller achieves nonlinear behavior based on sensor modalities, rather than relying on predefined conditional rule-based on locomotion functions. This system was validated through both physical and simulation testing based on multiple sensor data and behavioral patterns. Utilizing a potential function in multimodal locomotion control was verified to enable transitions between two or three behaviors. Implementing the control method as a multimodal controller is expected to enhance its application in underwater exploration. Our project page is at https://tasada038.github.io/multi-jointed-bur/.

Problem

• Biomimetic Underwater Robots
• Multimodal Locomotion
• Locomotion Control
• Behavioral Limitations

Innovation

• Multimodal locomotion control
• Biomimetic underwater robots
• Potential function
• Sensor-based nonlinear control
• Multi-jointed mechanism