Dynamics, Control, and Estimation for Aerial Robots Tethered by Cables or Bars

Abstract

We consider the problem of controlling an aerial robot connected to the ground by a passive cable or a passive rigid link. We provide a thorough characterization of this nonlinear dynamical robotic system in terms of fundamental properties such as differential flatness, controllability, and observability. We prove that the robotic system is differentially flat with respect to two output pairs: elevation of the link and attitude of the vehicle; elevation of the link and longitudinal link force (e.g., cable tension, or bar compression). We show the design of an almost globally convergent nonlinear observer of the full state that resorts only to an onboard accelerometer and a gyroscope. We also design two almost globally convergent nonlinear controllers to track any sufficiently smooth time-varying trajectory of the two output pairs. Finally we numerically test the robustness of the proposed method in several far-from-nominal conditions: nonlinear cross-coupling effects, parameter deviations, measurements noise and non ideal actuators.

Cited by in corpus (7)

• Full-Pose Tracking Control for Aerial Robotic Systems with Laterally-Bounded Input Force
• Human-State-Aware Controller for a Tethered Aerial Robot Guiding a Human by Physical Interaction
• Technical Note for "A Geodesic Approach for the Control of Tethered Quadrotors"
• Static-Equilibrium Oriented Interaction Force Modeling and Control of Aerial Manipulation with Uni-Directional Thrust Multirotors
• Redundant Observer-Based Tracking Control for Object Extraction Using a Cable Connected UAV
• A Control Theoretic Study on Omnidirectional MAVs with Minimum Number of Actuators and No Internal Forces at Any Orientation
• Asymptotically Stable Observer-based Controller for Attitude Tracking with Systematic Convergence