Active Physical Interaction Control for Aerial Manipulator Based on External Wrench Estimation

This article investigates the active physical interaction problem of an aerial manipulator in terms of capability, reliability, and costs. Then, an active physical interaction control architecture is presented for the aerial manipulator to achieve both stable motion and interaction behaviors with external wrench estimation. Specifically, an external wrench estimator in absence of the acceleration and wrench measurements is designed to regulate the interaction point of the aerial manipulator with a minimal sensor condition. Next, a force tracking impedance control strategy with variable stiffness is presented to guarantee the contact stability and force tracking of the aerial manipulator with uncertain contact targets. Further, utilizing the knowledge of prescribed performance and terminal sliding mode surface, a pose controller is proposed to implement the dynamic response speed and accuracy control of the aerial manipulator, which provides a prerequisite for the realization of reliable physical interaction tasks. The stability of the proposed control architecture is analyzed through Lyapunov tools. Moreover, the feasibility and performance of the proposed control architecture are validated via simulations and real-world contact experiments.