Raphael Zufferey's research while affiliated with École Polytechnique Fédérale de Lausanne and other places

Publications (31)

Article
Full-text available
Flapping wings produce lift and thrust in bio-inspired aerial robots, leading to quiet, safe and efficient flight. However, to extend their application scope, these robots must perch and land, a feat widely demonstrated by birds. Despite recent progress, flapping-wing vehicles, or ornithopters, are to this day unable to stop their flight. In this p...
Article
Full-text available
Monitoring of aquatic habitats for water quality and biodiversity requires regular sampling, often in off-shore locations and underwater. Such sampling is commonly performed manually from research vessels, or if autonomous, is constrained to permanent installations. Consequentially, high frequency ecological monitoring, such as for harmful algal bl...
Preprint
Full-text available
Biomimetic and Bioinspired design is not only a potent resource for roboticists looking to develop robust engineering systems or understand the natural world. It is also a uniquely accessible entry point into science and technology. Every person on Earth constantly interacts with nature, and most people have an intuitive sense of animal and plant b...
Article
Full-text available
Aerial–aquatic robotic vehicles show great potential in assisting in disaster response and environmental monitoring. However, to undertake these missions, they need to overcome the challenges of power requirements for takeoff and the difficulty of transitioning reliably between the air and water media. The use of superhydrophobic surfaces offers so...
Preprint
Flapping wings are a bio-inspired method to produce lift and thrust in aerial robots, leading to quiet and efficient motion. The advantages of this technology are safety and maneuverability, and physical interaction with the environment, humans, and animals. However, to enable substantial applications, these robots must perch and land. Despite rece...
Preprint
Full-text available
Flapping wings are a bio-inspired method to produce lift and thrust in aerial robots, leading to quiet and efficient motion. The advantages of this technology are safety and maneuverability, and physical interaction with the environment, humans, and animals. However, to enable substantial applications, these robots must perch and land. Despite rece...
Chapter
The previous chapters presented hybrid robot concepts and prototypes relying on the use of fixed wings for lift generation. The higher flight efficiency of such devices makes them suitable for covering large distances and can even serve to extend their locomotion envelope (see Chap. 11).
Chapter
A wealth of research exists into the broader question of how robotic mobility can be expanded beyond a single domain/terrain. A significant amount of recent research attention has been given to the implementation of aerial-terrestrial mobility into miniature robots [94], resulting in mobile robots with shared subsystems and additional mechanisms wh...
Chapter
This book would not be complete without a chapter on practical hardware and software elements used throughout the presented robots. We hope that this can serve as a rough toolbox for aerial-aquatic vehicle development, and cover some of the prototyping choices that are often under-reported in academic literature, but consume outsize research time.
Chapter
In a previous chapter an idealised water jet thruster was analysed, and it was argued that the most effective system would use large pressures to drive a small volume of water. In this chapter a more detailed physical model of water jet propulsion will be introduced, and the key design features of a jet thruster prototype detailed. Consistent stati...
Chapter
This book introduces the concept of small, unmanned aerial-aquatic robotics. This novel field of research aims to merge the benefits of flight and aquatic operation into one lightweight autonomous platform. As the reader will have seen in this book, wildly different robots can be envisioned as solutions to this formidable challenge.
Chapter
Having measured the longitudinal aerodynamics of the AquaMAV in wind tunnel tests (cf. Chap. 7), the data gathered can then be used to analyse the dive performance of the vehicle, as well as estimate and evaluate its dynamic properties. As in Sect. 6.4, we begin by considering a quasi-steady state model, where, furthermore, the aerial and aquatic p...
Chapter
In this chapter the design of a plunge diving AquaMAV is detailed. This enhanced AquaMAV prototype is capable of propelled flight, wing retraction for diving into water and jet propelled aquatic escape. The selection process for key components is detailed, as well as the specific attributes necessary for aerial-aquatic locomotion. The AquaMAV inclu...
Chapter
In the previous chapters, aquatic launch and dives into water with small flying robots have been demonstrated. An AquaMAV prototype was presented which was capable of self propelled-flight in air and able to escape water, but this robot had no means of propelling itself beneath the surface. To add aquatic locomotion it is attractive to use the same...
Chapter
The field of aerial-aquatic robotics promises tremendous benefits in data collection as well as unmatched flexibility and remote access. However, the majority of existing aerial-aquatic robots are unable to perform scientific tasks at significant depth, limited by the weight penalty that any pressure resistant container would add. In addition, seal...
Chapter
We live on a water-covered planet that is facing rapid change, both globally and locally, due to a combination of human behaviour and natural phenomena [31]. Understanding these changes requires in-depth scientific understanding of our environment. Key to enabling this is the fast, accurate and repeated provision of extensive physical data. However...
Chapter
Most animals use different forms of locomotion to move through a varied environment. This allows them to adapt to find food, escape threats or migrate, while minimising their energetic cost of locomotion. To do so, animals must use the same locomotor modules to perform specialised tasks that often have opposed requirements. For example, an animal d...
Chapter
Several systems have been developed with aerial-aquatic locomotion capabilities but without demonstrating consecutive transitions to flight from water. Moreover, while some multirotor vehicles possess the ability to operate in both air and water [108, 109], the transition to flight is typically constrained to very calm sea conditions. Fixed-wing ro...
Chapter
This chapter presents an overview of some fundamental physical laws and concepts at play in generic, as clarified in Figs. 5.1 and 5.2. The vehicle-specific physics are then introduced in the following chapters and form the basis for locomotion derived for the different vehicles presented.
Chapter
Water covers 363 million square km, or 72% of the earth’s surface. The vast majority of this water is saline (96%), frozen (2%) or groundwater (1%). The 10\(^5\) km\(^3\) of surface freshwater (0.008%) is in turn concentrated almost entirely in three large great lake systems (Fig. 3.1), with a vanishing small amount of surface freshwater forming la...
Book
This book reports on the state of the art in the field of aerial-aquatic locomotion, focusing on the main challenges concerning the translation of this important ability from nature to synthetic systems, and describing innovative engineering solutions that have been applied in practice by the authors at the Aerial Robotics Lab of Imperial College L...
Conference Paper
Full-text available
Autonomous aquatic vehicles capable of flight can deploy more rapidly, access remote or constricted areas, overfly obstacles and transition easily between distinct bodies of water. This new class of vehicles can be referred as Unmanned Aerial-Aquatic Vehicles (UAAVs), and is capable of reaching distant locations rapidly, conducting measurements and...
Article
Autonomous lightweight flapping-wing robots show potential to become a safe and affordable solution for rapidly deploying robots around humans and in complex environments. The absence of propellers makes such vehicles more resistant to physical contact, permitting flight in cluttered environments, and collaborating with humans. Importantly, the pro...
Article
Full-text available
Unmanned aerial vehicles (UAVs) have been shown to be useful for the installation of wireless sensor networks (WSNs). More notably, the accurate placement of sensor nodes using UAVs, opens opportunities for many industrial and scientific uses, in particular, in hazardous environments or inaccessible location. This publication proposes and demonstra...
Article
Aerial-aquatic robots possess the unique ability of operating in both air and water. However, this capability comes with tremendous challenges, such as communication incompatibility, increased airborne mass, potentially inefficient operation in each of the environments and manufacturing difficulties. Such robots, therefore, typically have small pay...
Article
Full-text available
Robotic vehicles that are capable of autonomously transitioning between various terrains and fluids have received notable attention in the past decade due to their potential to navigate previously unexplored and/or unpredictable environments. Specifically, aerial-aquatic mobility will enable robots to operate in cluttered aquatic environments and c...
Conference Paper
Full-text available
Aerial-aquatic mobility is envisaged to significantly facilitate applications involving aquatic sampling or underwater surveying. Allowing water vehicles to take flight would allow for rapid deployment, access to remote areas, over-flying of obstacles and easy transitioning between separate bodies of water. The use of a single vehicle capable of re...
Article
Despite significant research progress on small-scale aerial–aquatic robots, most existing prototypes are still constrained by short operation times and limited performance in different fluids. The main challenge is to design a vehicle that satisfies the partially conflicting design requirements for aerial and aquatic operations. In this letter we p...
Article
We present a power and control autonomous insect-scale legged robot, the Harvard Ambulatory MicroRobot with RF communication (HAMR-F). At only 2.79g and 4.5cm in length, HAMR-F is capable of locomotion at speeds up to 17.2cm/s (3.8 body lengths per second) with an onboard battery. Two microcontrollers and custom drive electronics independently cont...
Article
From millimeter-scale insects to meter-scale vertebrates, several animal species exhibit multimodal locomotive capabilities in aerial and aquatic environments. To develop robots capable of hybrid aerial and aquatic locomotion, we require versatile propulsive strategies that reconcile the different physical constraints of airborne and aquatic enviro...

Citations

... Energy recovery is an interesting possibility to extend the operation time of robots. Solar charging could enable flapping-wing robots to travel on longer missions 5,6 . Additionally, the capability to perch will enable many other applications, e.g. ...
... S2for actuator comparison). The selected conventional tail configuration yields high pitch authority, an important metric for precise vertical positioning(35). Low weight and extended pitch deflection are possible using the new direct drive, carbon fiber tail design, see description in Text S6 andFig. ...
... This is achieved by providing in essence, means for researchers to access waterbodies from more convenient launch points, collect aerial data of said water-bodies, and perform direct measurements at the water surface or/and at depth at multiple locations. Literature in the UAAV field is extensive, Zeng et al. (2022), and varied mission profiles have been proposed thus far, Farinha et al. (2021). Amongst other achievements, UAAVs have been shown overcoming obstacles and escaping cluttered aquatic environments (Zufferey et al. (2019a); Siddall et al. (2017); Tétreault et al. (2020)), autonomously traveling underwater ), and performing long duration sailing missions (Zufferey et al. (2019b)). ...
... The first implementation of the perching method resulted in the ornithopter P-Flap for Perching Flapping-Wing Robot, see the specifications in Supplementary Table 1. This design is initially based on the pre-existing E-Flap robot 30 . This flapping-wing vehicle features 100% payload capacity and offers stable flight velocities as low as 3 m/s, both possible thanks to the lightweight construction and low wing loading of 16 N/m 2 . ...
... From a branch, robots can observe and track animals both on the ground and in flight. Physical interaction with a tree could permit microscopic analysis of the branch's surface as well 4 . Sample return of a leaf can be envisioned, enabling biologists to study those systems with minimum collection effort. ...
... These sensing devices still propose a threat to the environment in which they are deployed in, as they are non-degradable and potentially toxic. Robotic platforms can be utilized to automatize data sampling while reducing risks and costs (Debruyn et al., 2020;. If the drone's control is lost, its structure and active components can pollute and harm the environment, targeted for monitoring. ...
... Flight enables UAAVs to cover distances rapidly, avoid obstacles and move between separate bodies of water, while being able to carry out a variety of tasks that involve water interaction, such as water sampling, marine investigation, monitoring of fragile environments (such as coral reefs), or industrial maintenance work (for instance around offshore platforms). State of the art designs achieve this particular type of multimodal locomotion through adaptable physical morphology [1] and/or control strategy [2] adaptation, sometimes inspired by nature [3]. Literature on UAAVs is extensive [4] and covers vehicles ranging from the micro-scale to several meters wingspan, as well as a variety of flying vehicle categories, i.e. fixed-wing, rotorcraft, ornithopters and jet-thrusters, as shown in Table I. ...
... More recently, hybrid mobile robots, which can fly after swimming, or swim after flying, have drawn the attention of researchers (Zeng et al., 2022). However, most of the water-leaping robots in the literatures use gas thruster or water jet to produce a large thrust for leaping out of water (O'Dor et al., 2013;Chen et al., 2017;Siddall et al., 2017;Zufferey et al., 2019). To the best of our knowledge, the dolphin-like robots reported in (Yu et al., 2016a;Yu et al., 2019) are only water-leaping fish-like robot swimming by tail-beating motion. ...
... Flapping wing-type designs [3] [2] implemented versatile flapping propulsive strategies for the water entry and exit operation. Another wing-type multi-modal robots utilize air to enhance its flying [4]. Passive fixed wingtype designs [5] adjust its bouyance by passively flooding or draining its wings. ...
... While there are growing efforts to achieve insect-level autonomy in these robots, it is still a challenge to match their natural-born counterparts, i.e., living ambulatory insects. While control autonomy was achieved in various insect-scale mobile robots (Chen et al. 2020;de Rivaz et al. 2018;Goldberg et al. 2018;St. Pierre and Bergbreiter 2019;Yang et al. 2020), power autonomy was demonstrated only in a few platforms, like HAMR-F or Robeetle (Yang et al. 2020). ...