Adaptive Stiffness Visual Servoing for Unmanned Aerial Manipulators With Prescribed Performance

In this article, an robust adaptive stiffness visual servoing control method is proposed to guarantee a compliant physical interaction with a prescribed performance of the unmanned aerial manipulator (UAM) in the presence of disturbances and modeling uncertainties. First, to address the slow response speed of visual servoing control when image features change, a visual servo position controller with prescribed performance is adopted to enhance the convergence speed through the gradually convergent error boundary. Second, considering the influence of disturbances and modeling uncertainties caused by the flight platform on the admittance accuracy during physical interaction, an robust adaptive stiffness physical interaction controller is introduced, generating stable admittance command image features to ensure a reliable interaction force. Finally, physical comparative and real-world experimental studies are conducted to validate the feasibility and performance of the proposed method. The results demonstrate that the UAM under control is capable of exhibiting specified performance during contact operations, allowing smooth adaptation to changes in contact forces.