Design, Modeling and Control of a Deformable Quadrotor Using McKibben Pneumatic Actuators

Deformable aerial robots with articulated structures have attracted increasing attention for their ability to perform complex tasks through in-flight morphological adaptation. However, most existing implementations rely on mechanical actuators, which increase total weight and vulnerability to external impacts. To address these limitations, we propose a deformable quadrotor platform actuated by antagonistic McKibben Pneumatic Actuators (MPAs), which offer lightweight, flexible, and robust actuation. We develop a dynamic model of the quadrotor incorporating joint angles actuated by MPAs, and characterize the relationship between internal pneumatic pressure and joint angle. Based on this model, we construct a prototype platform and evaluate its performance through a series of experiments. We first identify the optimal actuator length by analyzing joint deformation under varying pressure conditions. Next, we demonstrate stable flight during in-air morphing transitions, such as X-type, T-type, and H-type configurations, with position and attitude errors remaining within acceptable ranges. The results confirm that the proposed system enables stable flight using soft pneumatic actuation and paves the way for future aerial manipulation and morphing applications.