Here we experimentally quantify the effects of wing morphological and inertial parameters on flapping flight performance. Through running at-scale, passive pitching experiments with different wing designs, we compare the relative importance of wing inertia, wing shape, and wing-actuation pairing. We find wing inertia strongly influences the coupling between stroke and pitch dynamics, which directly impacts lift production and efficiency. Flapping resonance frequency is reduced as wing aspect ratio or area moment increases. Further, wing leading edge design strongly influences chordwise center of pressure, which further impacts pitching dynamics. Based on our experimental results we propose a new wing design and measure 37% increase in mean lift relative to a previous work.

Here we present a suite of theoretical, computational, and experimental studies culminating in the first aerial and aquatic capable insect-scale robot. We develop a computational fluid dynamics (CFD) simulation to model fluid-wing interaction in air and water. From CFD and a system dynamics analysis we predict that a multi-modal flapping strategy will enable locomotion in both air and water for a single device. We validate the CFD predictions by running at-scale, robotic wing-flapping experiments. Finally, we demonstrate for the first time a flying and swimming capable flapping-wing insect-like robot.

Despite having achieved unconstrained stable flight, the insect-scale flapping-wing robot is still tethered for power and control. Towards the goal of operating a biologically-inspired robot autonomously outside of laboratory conditions. In this paper, we simulate outdoor disturbances in the laboratory setting and investigate the effects of wind gusts on the flight dynamics of a millimeter-scale flapping wing robot. Simplified models describing the disturbance effects on the robot's dynamics are proposed, together with two disturbance rejection schemes capable of estimating and compensating for the disturbances. The proposed methods are experimentally verified. The results show that they reduced the root mean square position errors by approximately 50% when the robot was subject to 60 cm·s-1horizontal wind.

Without sufficient payload capacity to carry necessary electronic components, flying robots at the scale of insects cannot fly autonomously. Using a simple scaling heuristic to determine a few salient vehicle properties, we develop a vehicle design that possesses the requisite payload capacity for the full suite of required components for control autonomy. We construct the vehicle using state-of-the-art methods, producing a 380 mg vehicle with a 115 mg payload capacity, and demonstrate controlled hovering of the fully-loaded vehicle. The payload-capable vehicle demonstrated here establishes a scalable vehicle design and validates current fabrication methods, laying a foundation for an eventual, fully-integrated robotic system.

Inspired by the agility of flying insects and the recent development on an insect-scale aerial vehicle, we propose a single-loop adaptive flight control suite designed with an emphasis on the ability to track dynamic trajectories as a step towards the goal of performing acrobatic maneuvers as observed in real insects. Instead of the conventional approach of having cascaded control loops, the proposed controller directly regulates the commanded torques to stabilize the attitude and lateral position in a single loop. The method is verified by performing trajectory following flights with the insect-like robot. The results show that the position errors during trajectory following flights are comparable to those observed from steady hovering flights.

Challenges for controlled flight of a robotic insect are due to the inherent instability of the system, complex fluid-structure interactions, and the general lack of a complete system model. In this paper, we propose theoretical models of the system based on the limited information available from previous work and a comprehensive adaptive flight controller that is capable of coping with uncertainties in the system. We have demonstrated that the proposed methods enable the robot to achieve sustained hovering flights with relatively small errors compared to a similar but non-adaptive approach. Furthermore, vertical takeoff and landing flights are also shown to illustrate the fidelity of the flight controller.

The split actuator microrobotic bee is the first flight-capable, insect-scale flapping-wing micro air vehicle that uses “split-cycle” constant-period frequency modulation to control body forces and torques. Building this vehicle is an intricate challenge, but by leveraging a maturing fabrication technology for microscale devices, we have developed a solution to tackle the design and fabrication difficulties. We show that the design is able to independently modulate the motions of both wings and produce roll, pitch, and yaw torques, as well as a peak lift force of 1.3 mN, in a 70mg package.

This work presents the design, fabrication, capabilities, and obstacle traversal mechanics of MEDIC (Millirobot Enabled Diagnostic of Integrated Circuits), a small legged robot able to overcome a varied array of obstacles. MEDIC features a hull that keeps its body in contact with the ground at all times, and uses only four actuators to move forward, turn, mount obstacles, and move in reverse. The chassis is fabricated using a Smart Composite Microstructures (SCM) approach and the robot is actuated by coiled Shape Memory Alloy (SMA). MEDIC also features a camera which will be useful for navigation in the future.

Flapping-wing air vehicles can improve efficiency by running at resonance to reduce inertial costs of accelerating and decelerating the wings. For battery-powered, DC motor-driven systems with gears and cranks, the drive torque and velocity is a complicated function of battery voltage. Hence, resonant behavior is not as well defined as for flapping-wing systems with elastic actuators. In this paper, we analyze a resonant drive to reduce average battery power consumption for DC motor-driven flapping-wing robots. We derive a nondimensionalized analysis of the generic class of a motor-driven slider crank, considering motor and battery resistance. This analysis is used to demonstrate the benefits of efficient resonant drive on a 5.8 g flapping-wing robot and experiments showed a 30% average power reduction by integrating a tuned compliant element.