Small Dynamic Morphing Systems
Modeling and Controls of Fluid-Structure Interactions (FSI) in Dynamic Morphing Flight
The primary aim of this study is to enhance the accuracy of our aerodynamic Fluid-Structure Interaction (FSI) model to support controlled 3D flight trajectories by Aerobat, a dynamic morphing winged drone. Building on our existing Unsteady Aerodynamic model based on horseshoe vortices, we introduce Aerobat version β, designed for attachment to a Kinova arm. We conduct experiments to gather force-moment data from the robotic arm, which is then used to fine-tune our unsteady model for banking turns. The tuned FSI model, combined with a collocation control strategy, is employed to achieve 3D banking turns in simulation. The study’s primary contribution is a methodical approach to calibrate our FSI model for predicting complex maneuvers and assessing its potential for closed-loop flight control of Aerobat using an optimization-based collocation method.
Banking Turn of High-DOF Dynamic Morphing Wing Flight by Shifting Structure Response Using Optimization
Controlling 3D flight in a flapping wing robot is a challenging problem due to the complex dynamics of aerodynamic forces on the wing membrane. Bats perform agile aerial maneuvers, such as tight banking and bounding flight, using their highly flexible wings. In this work, we develop a control method for a bio-inspired bat robot, Aerobat, which uses small, low-powered actuators to manipulate the flapping gait and the resulting aerodynamic forces. We implemented a controller based on a collocation approach to track desired roll and execute a banking maneuver, intended for use in trajectory tracking. This controller is tested in simulation to demonstrate its performance and feasibility.
Actuation and Flight Control of High-DOF Dynamic Morphing Wing Flight by Shifting Structure Response
Bat’s dynamically morphing wings are highly versatile with many active and passive modes which allows them to display highly dexterous flight maneuvers. We take inspiration from bat wings and attempt to mimic their high degrees of freedom and flexibility in our small bat robot with dynamically morphing wings called the Aerobat. This small robot uses linkages, or computational structure, to animate the robot’s flapping gait. In this work, we present the theoretical framework of using small low-energy actuators, called the primers, to adjust highly sensitive linkages length for changing the robot’s flapping gait and use it to control the robot’s orientation. This method is applied in a dynamic simulation to show its feasibility.
Actuation Fast Estimation of Morphing Wing Flight Dynamics Using Neural Networks and Cubature Rules
Fluidic locomotion of flapping Micro Aerial Vehicles (MAVs) is complex, especially when insect flight dynamics (fast flapping, light wings) don’t apply, making standard averaging techniques ineffective. Our goal is to model complex aerial locomotion where wings, constituting a large part of body mass, deform in multiple directions, resulting in morphing wings with significant inertial effects. These systems involve complex inertial, Coriolis, and gravity terms due to high degrees of freedom. We employ Algorithmic Differentiation (AD) and Bayesian filters, computed with cubature rules, to efficiently estimate fluid-structure interactions. Using cubature rules for Gaussian-weighted integrals and AD, we compute the multi-degree-of-freedom dynamics of morphing MAVs accurately and efficiently, enabling closed-loop feedback control.
Hovering Control of Flapping Wings in Tandem with Multi-Rotors
This work briefly covers our efforts to stabilize the flight dynamics of Northeatern’s tailless bat-inspired micro aerial vehicle, Aerobat. Flapping robots are not new. A plethora of examples is mainly dominated by insect-style design paradigms that are passively stable. However, Aerobat, in addition to being tailless, possesses morphing wings that add to the inherent complexity of flight control. The robot can dynamically adjust its wing platform configurations during gaitcycles, increasing its efficiency and agility. We employ a guard design with manifold small thrusters to stabilize Aerobat’s position and orientation in hovering, a flapping system in tandem with a multi-rotor. For flight control purposes, we take an approach based on assuming the guard cannot observe Aeroat’s states. Then, we propose an observer to estimate the unknown states of the guard which are then used for closed-loop hovering control of the Guard-Aerobat platform.