A Morphing Land–Air Robot with Adaptive Capabilities for Confined Environments

Highlights: What are the main findings? A morphing wheeled land–air robot is developed by integrating a multi-link foldable arm mechanism and a variable-diameter wheel mechanism to achieve land–air mode switching, in-flight morphing, flexible dual landing strategies, and smooth transitions between wheeled and legged locomotion. The study systematically investigates the aerodynamic effects induced by the addition of wheels, evaluates the performance of the two morphing mechanisms, and validates the robot’s performance through comprehensive outdoor tests, including obstacle traversal and folded takeoff/landing. What are the implications of the main findings? The proposed design greatly enhances mobility and flexibility across air and ground environments, reducing unnecessary takeoffs, lowering energy consumption, and improving overall reliability. The unique multi-modal architecture forms a unified aerial–ground operational framework, offering higher efficiency, stability, and robustness when navigating complex real-world environments. Traditional wheeled ground robots offer high energy efficiency and excellent mobility on flat terrain but are constrained by their fixed structures, making it difficult to overcome obstacles or adapt to complex environments. To address these limitations, this paper presents a morphing wheeled land–air robot (MW-LAR) that integrates ground locomotion and quadrotor flight. By incorporating foldable arms and variable-diameter wheels, the MW-LAR can not only switch between ground and flight modes, but also achieve transitions between wheeled and legged locomotion in the ground mode. The foldable arms support seamless aerial-to-ground transitions and in-flight morphing, while the variable-diameter wheels facilitate efficient obstacle traversal on the ground. Benefiting from the design of foldable arms, two complementary landing approaches, namely direct quadrotor landing and ground-mode landing, are implemented to explore different aerial-to-ground transition modes and to improve landing safety and switching efficiency. Experimental results demonstrate that the MW-LAR achieves stable and energy-efficient performance across multiple locomotion modes and complex environments, highlighting its potential for integrated land–air mobility applications.