A coordinated framework of aerial manipulator for safe and compliant physical interaction

Abstract

The challenge of ensuring compliant behavior in aerial manipulators during physical interactions is addressed in this study. This work presents a coordinated interactive framework for aerial manipulators, specifically designed to ensure compliant physical interactions during contact with the surroundings. Without the reliance on force sensors, an external force estimator is employed to recognize interaction intentions. The coordinated framework leverages a Model Predictive Control (MPC) planner equipped with adaptive weights, facilitating the coordination of movements for both the quadrotor and manipulator. The adaptive adjustment of weights in the cost function allows for the attainment of diverse interaction behaviors in response to unexpected external forces. Notably, the methodology stands out from current control strategies by incorporating autonomous stiffness adjustment in response to interaction forces, thereby optimizing the delicate balance between safety and precision. The passivity of the system is guaranteed by using a Lyapunov-like function during the physical interaction. The effectiveness of the proposed framework is validated by experiments for the scenario of human operator and aerial manipulator collaborative work.