Publications
71 results found
Stephens B, Nguyen H-N, Hamaza S, et al., 2023, An integrated framework for autonomous sensor placement with aerial robots, IEEE-ASME Transactions on Mechatronics, Vol: 28, Pages: 38-49, ISSN: 1083-4435
Aerial manipulators have the unique ability to coverwide-spread areas within a single mission, making them ideal forthe transport and placement of sensors required to develop aninstrumented environment. Recent work in the field has focusedon controllers for aerial interaction that account for complianceduring contact-based tasks, omitting integration concerns that arecritical to an automated sensor placement solution. Furthermore,state-of-the-art flying base manipulators are often mechanicallyand computationally complex, reducing their efficiency andpracticality. Within this work, we present an interactive framework for autonomous sensor placement that incorporates bothmechanical and software based compliance, optimised for use ona simple coplanar quadrotor. Under appropriate actuation andperception constraints, we detail the development of a control,perception, and motion planning strategy to enable automatedsensor placement that relies solely on onboard computationand sensing, thus presenting a fully contained and accessiblesensor placement approach capable of robust interaction withthe environment. An extended finite-state machine is developedto facilitate automated mission planning.Extensive flight experiments are performed to validate theeffectiveness of each sub-system, as well as the integrated solution.Experiments result in trajectory tracking errors under 10 mm aswell as onboard mass estimation errors under 0.7 % for sensorsof various weights. A statistical analysis of 162 flight experimentsshows the proposed framework’s ability to autonomously placesensors within 10 cm of the target with a success rate of93.8 % and 95 % confidence interval of (89 %, 97 %), thusconfirming the robustness and repeatability of our approach. Avideo showcasing our implemented solution can be found here:https://youtu.be/4R8DhVpEbSQ.
Zheng P, Xiao F, Pham N, et al., 2023, Metamorphic aerial robot capable of mid-air shape morphing for rapid perching, Scientific Reports, Vol: 13, ISSN: 2045-2322
Aerial robots can perch onto structures at heights to reduce energy use or to remain firmly in place when interacting with their surroundings. Like how birds have wings to fly and legs to perch, these bio-inspired aerial robots use independent perching modules. However, modular design not only increases the weight of the robot but also its size, reducing the areas that the robot can access. To mitigate these problems, we take inspiration from gliding and tree-dwelling mammals such as sugar gliders and sloths. We noted how gliding mammals morph their whole limb to transit between flight and perch, and how sloths optimized their physiology to encourage energy-efficient perching. These insights are applied to design a quadrotor robot that transitions between morphologies to fly and perch with a single-direction tendon drive. The robot’s bi-stable arm is rigid in flight but will conform to its target in 0.97 s when perching, holding its grasp with minimal energy use. We achieved a 30% overall mass reduction by integrating this capability into a single body. The robot perches by a controlled descent or a free-falling drop to avoid turbulent aerodynamic effects. Our proposed design solution can fulfill the need for small perching robots in cluttered environments.
Zhang K, Chermprayong P, Xiao F, et al., 2022, Aerial additive manufacturing with multiple autonomous robots, Nature, Vol: 609, Pages: 709-717, ISSN: 0028-0836
Additive manufacturing methods 1–4 using static and mobile robots are beingdeveloped for both on-site construction 5–8 and off-site prefabrication 9, 10. Here we introduce a new method of additive manufacturing, referred to as Aerial Additive Manufacturing (Aerial-AM), that utilizes a team of aerial robots inspiredby natural builders 11 such as wasps who use collective building methods 12, 13. We present a scalable multi-robot 3D printing and path planning framework that enables robot tasks and population size to be adapted to variations in print geometry throughout a building mission. The multi-robot manufacturing framework allows for autonomous 3D printing under human supervision, real-time assessment of printed geometry and robot behavioural adaptation. To validate autonomous Aerial-AM based on the framework, we develop BuilDrones for depositing materials during flight and ScanDrones for measuring print quality, and integrate a generic real-time model-predictive-control scheme with the Aerial-AM robots. In addition, we integrate a dynamically self-aligning deltamanipulator with the BuilDrone to further improve manufacturing accuracy to 5mm for printing geometry with precise trajectory requirements, and develop four cementitious-polymeric composite mixtures suitable for continuous material deposition. We demonstrate proof-of-concept prints including a cylinder of 2.05m with a rapid curing insulation foam material and a cylinder of 0.18m with strutural pseudoplastic cementitious material, a light-trail virtual print of a dome-like geometry, and multi-robot simulations. Aerial-AM allows manufacturing in-flight2 and offers future possibilities for building in unbounded, at height, or hard to access locations.
Stephens B, Orr L, Kocer BB, et al., 2022, An aerial parallel manipulator with shared compliance, IEEE Robotics and Automation Letters, Vol: 7, Pages: 11902-11909, ISSN: 2377-3766
Accessing and interacting with difficult to reach surfaces at various orientations is of interest within a variety of industrial contexts. Thus far, the predominant robotic solution to such a problem has been to leverage the maneuverability of a fully actuated, omnidirectional aerial manipulator. Such an approach, however, requires a specialised system with a high relative degree of complexity, thus reducing platform endurance and real-world applicability. The work here presents a new aerial system composed of a parallel manipulator and conventional, underactuated multirotor flying base to demonstrate interaction with vertical and non-vertical surfaces. Our solution enables compliance to external disturbance on both subsystems, the manipulator and flying base, independently with a goal of improved overall system performance when interacting with surfaces. To achieve this behaviour, an admittance control strategy is implemented on various layers of the flying base's dynamics together with torque limits imposed on the manipulator actuators. Experimental evaluations show that the proposed system is compliant to external perturbations while allowing for differing interaction behaviours as compliance parameters of each subsystem are altered. Such capabilities enable an adjustable form of dexterity in completing sensor installation, inspection and aerial physical interaction tasks. A video of our system interacting with various surfaces can be found here: https://youtu.be/38neGb8-lXg .
Li L, Wang S, Zhang Y, et al., 2022, Aerial-aquatic robots capable of crossing the air-water boundary and hitchhiking on surfaces., Science Robotics, Vol: 7, Pages: 1-13, ISSN: 2470-9476
Many real-world applications for robots-such as long-term aerial and underwater observation, cross-medium operations, and marine life surveys-require robots with the ability to move between the air-water boundary. Here, we describe an aerial-aquatic hitchhiking robot that is self-contained for flying, swimming, and attaching to surfaces in both air and water and that can seamlessly move between the two. We describe this robot's redundant, hydrostatically enhanced hitchhiking device, inspired by the morphology of a remora (Echeneis naucrates) disc, which works in both air and water. As with the biological remora disc, this device has separate lamellar compartments for redundant sealing, which enables the robot to achieve adhesion and hitchhike with only partial disc attachment. The self-contained, rotor-based aerial-aquatic robot, which has passively morphing propellers that unfold in the air and fold underwater, can cross the air-water boundary in 0.35 second. The robot can perform rapid attachment and detachment on challenging surfaces both in air and under water, including curved, rough, incomplete, and biofouling surfaces, and achieve long-duration adhesion with minimal oscillation. We also show that the robot can attach to and hitchhike on moving surfaces. In field tests, we show that the robot can record video in both media and move objects across the air/water boundary in a mountain stream and the ocean. We envision that this study can pave the way for future robots with autonomous biological detection, monitoring, and tracking capabilities in a wide variety of aerial-aquatic environments.
Kocer B, Hady A, Kandath H, et al., 2021, Deep neuromorphic controller with dynamic topology for aerial robots, ICRA 2021, Publisher: IEEE, Pages: 110-116
Current aerial robots are increasingly adaptive; they can morph to enable operation in changing conditions to complete diverse missions. Each mission may require the robot to conduct a different task. A conventional learning approach can handle these variations when the system is trained for similar tasks in a representative environment. However, it may result in overfitting to the new data stream or the failure to adapt, leading to degradation or a potential crash. These problems can be mitigated with an excessive amount of data and embedded model, but the computational power and the memory of the aerial robots are limited. In order to address the variations in the model, environment as well as the tasks within onboard computation limitations, we propose a deep neuromorphic controller approach with variable topologies to handle each different condition and the data stream with a feasible computation and memory allocation. The proposed approach is based on a deep neuromorphic (multi and variable layered neural network) controller with dynamic depth and progressive layer adaptation for each new data stream. This adaptive structure is combined with a switching function to form a sliding mode controller. The network parameter update rule guarantees the stability of the closed loop system by the convergence of the error dynamics to the sliding surface. Being the first implementation on an aerial robot in this context, the results illustrate the adaptation capability, stability, computational efficiency as well as the real-time validation.
Kovac M, Sequeira Guedes Tristany Farinha A, di Tria J, et al., 2021, Challenges in control and autonomy of unmanned aerial-aquatic vehicles, 29th Mediterranean Conference on Control and Automation (MED), Publisher: IEEE, Pages: 937-942
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 returning to base. This greatly improves upon current solutions, which often involve integrating different types of vehicles (e.g. vessels releasing underwater vehicles), or rely on manpower (e.g. sensors dropped manually from ships). Thanks to recent research efforts, UAAVs are becoming more sophisticated and robust. Nonetheless numerous challenges remain to be addressed, and particularly dedicated control and sensing solutions are still scarce. This paper discusses challenges and opportunities in UAAV control, sensing and actuation. Following a brief overview of the state of the art, we elaborate on the requirements and challenges for the main types of robots and missions proposed in the literature to date, and highlight existing solutions where available. The concise but wide-ranging overview provided will constitute a useful starting point for researchers undertaking UAAV control work.
Wiesemuller F, Winston C, Poulin A, et al., 2021, Self-sensing cellulose structures with design-controlled stiffness, IEEE Robotics and Automation Letters, Vol: 6, Pages: 4017-4024, ISSN: 2377-3766
Robots are often used for sensing and sampling in natural environments. Within this area, soft robots have become increasingly popular for these tasks because their mechanical compliance makes them safer to interact with. Unfortunately, if these robots break while working in vulnerable environments, they create potentially hazardous waste. Consequently, the development of compliant, biodegradable structures for soft, eco-robots is a relevant research area that we explore here. Cellulose is one of the most abundant biodegradable materials on earth, but it is naturally very stiff, which makes it difficult to use in soft robots. Here, we look at both biologically and kirigami inspired structures that can be used to reduce the stiffness of cellulose based parts for soft robots up to a factor of 19 000. To demonstrate this, we build a compliant force and displacement sensing structure from microfibrillated cellulose. We also describe a novel manufacturing technique for these structures, provide mechanical models that allow designers to specify their stiffness, and conclude with a description of our structure's performance.
Xiao F, Zheng P, Di Tria J, et al., 2021, Optic flow based reactive collision prevention for MAVs using the fictitious obstacle hypothesis, IEEE Robotics and Automation Letters, Vol: 6, Pages: 3144-3151, ISSN: 2377-3766
Optical flow sensors and optical flow divergence (OFD) have offered partial solutions for obstacle avoidance, landing, and perching with micro aerial vehicles. Theoretically, OFD can indicate the risk of collision, providing that the sensors’ field of view is bounded within a single flat surface on the obstacle. However, in the real world, directly measuring the risk of collision with OFD generates false alarms due to rapidly changing speeds and irregular surroundings. In this letter, we present a new obstacle detection strategy based on an extended Kalman filter (EKF) combining the OFD with inertial sensing. The introduction of a fictitious obstacle hypothesis and the use of the EKF estimates enable us to differentiate the surrounding-generated OFD from the OFD caused by the actual obstacle. An embedded constant zero-OFD controller is then used for post-detection emergency deceleration. The ultra-light OFD estimation and control system, with a mass of 20 g , estimates OFD at 160 Hz . The system was validated on a 158 g mini quadrotor in both laboratory and field tests. Experimental results illustrate that the presented system can achieve accurate obstacle detection, near-obstacle distance estimation, and controlled deceleration to prevent collisions. 1 1Video attachment: https://youtu.be/yIyYHYN0jOw.
Miriyev A, Kovac M, 2020, Skills for physical artificial intelligence, Nature Machine Intelligence, Vol: 2, Pages: 658-660, ISSN: 2522-5839
Synthesizing robots via physical artificial intelligence is a multidisciplinary challenge for future robotics research. An education methodology is needed for researchers to develop a combination of skills in physical artificial intelligence.
Farinha A, Zufferey R, Zheng P, et al., 2020, Unmanned aerial sensor placement for cluttered environments, IEEE Robotics and Automation Letters, Vol: 5, Pages: 6623-6630, ISSN: 2377-3766
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 locations. This publication proposes and demonstrates a new aerial sensor placement method based on impulsive launching. Since direct physical interaction is not required, sensor deployment can be achieved in cluttered environments where the target location cannot be safely approached by the UAV, such as under the forest canopy. The proposed method is based on mechanical energy storage and an ultralight shape memory alloy (SMA) trigger. The developed aerial system weighs a total of 650 grams and can execute up to 17 deployments on a single battery charge. The system deploys sensors of 30 grams up to 4 meters from a target with an accuracy of ±10 cm. The aerial deployment method is validated through more than 80 successful deployments in indoor and outdoor environments. The proposed approach can be integrated in field operations and complement other robotic or manual sensor placement procedures. This would bring benefits for demanding industrial applications, scientific field work, smart cities and hazardous environments [Video attachment: https://youtu.be/duPRXCyo6cY].
Hamaza S, Kovac M, 2020, Omni-drone: on the design of a novel aerial manipulator with omni-directional workspace, 17th International Conference on Ubiquitous Robots (UR), Publisher: IEEE, Pages: 153-158, ISSN: 2325-033X
Aerial manipulation is a nascent research area that offers major impact for infrastructure monitoring and repair. While several design and control methods have been presented, there is still a need for new mechatronic solutions that are structurally optimised for aerial manipulation tasks. In this paper we present a novel design for a manipulator tailored for aerial applications with a high level of morphological integration with the robot frame. A hybrid system is presented that comprises a 5-bar linkage parallel robot with an additional active joint for the swirling motion about a pivotal point. The design offers an omnidirectional workspace about the aerial vehicle, enhancing the versatility of the aerial system and the tasks that can be accomplished. The mechanical design of the proposed robot, the analysis of the kinematics and the study of the workspace are presented. The novel manipulator represents the first of its kind, enabling aerial interaction with ceilings, curved surfaces and side interaction with facades.
Zheng P, Tan X, Kocer BB, et al., 2020, TiltDrone: a fully-actuated tilting quadrotor platform, IEEE Robotics and Automation Letters, Vol: 5, Pages: 6845-6852, ISSN: 2377-3766
Multi-directional aerial platforms can fly in almost any orientation and direction, often maneuvering in ways their under-actuated counterparts cannot match. A subset of multi-directional platforms are fully-actuated multirotors, where all six degrees of freedom are independently controlled without redundancies. Fully-actuated multirotors possess much greater freedom of movement than conventional multirotor drones, allowing them to perform complex sensing and manipulation tasks. While there has been comprehensive research on multi-directional multirotor control systems, the spectrum of hardware designs remain fragmented. This paper sets out the hardware design architecture of a fully-actuated quadrotor and its associated control framework. Following the novel platform design, a prototype was built to validate the control scheme and characterize the flight performance. The resulting quadrotor was shown in operation to be capable of holding a stationary hover at 30° incline, and track position commands by thrust vectoring.
Debruyn D, Zufferey R, Armanini SF, et al., 2020, MEDUSA: a multi-environment dual-robot for underwater sample acquisition, IEEE Robotics and Automation Letters, Vol: 5, Pages: 4564-4571, ISSN: 2377-3766
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 payloads and a limited operational envelope, often making their field usage impractical. We propose a novel robotic water sampling approach that combines the robust technologies of multirotors and underwater micro-vehicles into a single integrated tool usable for field operations. The proposed solution encompasses a multirotor capable of landing and floating on the water, and a tethered mobile underwater pod that can be deployed to depths of several meters. The pod is controlled remotely in three dimensions and transmits video feed and sensor data via the floating multirotor back to the user. The ‚dual-robot‛ approach considerably simplifies robotic underwater monitoring, while also taking advantage of the fact that multirotors can travel long distances, fly over obstacles, carry payloads and manoeuvre through difficult terrain, while submersible robots are ideal for underwater sampling or manipulation. The presented system can perform challenging tasks which would otherwise require boats or submarines. The ability to collect aquatic images, samples and metrics will be invaluable for ecology and aquatic research, supporting our understanding of local climate in difficult-to-access environments.
Dams B, Sareh S, Zhang K, et al., 2020, Aerial additive building manufacturing: three-dimensional printing of polymer structures using drones, Proceedings of the Institution of Civil Engineers: Construction Materials, Vol: 173, Pages: 3-14, ISSN: 1747-650X
This paper describes the first aerial additive building manufacturing system developed to create and repair civil engineering structures remotely using polymers extruded from unmanned aerial robots (drones). The structural potential of three commercially available expanding polyurethane foams of varying density (LD40, Reprocell 300 and Reprocell 500), and their feasibility for deposition using an autonomous flying dual-syringe device is described. Test specimens consisting of one and two layers, with horizontal and vertical interfaces, were mechanically tested both parallel and perpendicular to the direction of expansion. LD40 specimens exhibited ductile failure in flexural tests and provided evidence that the interfaces between layers were not necessarily regions of weaknesses. Hand-mixed specimens of Reprocell 500 possessed compressive strengths comparable to those of concrete and flexural strengths similar to those of the lower range of timber, though they exhibited brittle failure. There are challenges to be faced with matching the performance of hand-mixed specimens using an autonomous dual-syringe deposition device, primarily concerning the rheological properties of the material following extrusion. However, the device successfully imported and deposited two liquid components, of varying viscosity, and maintained correct mixing ratios. This work has demonstrated the structural and operational feasibility of polyurethane foam as a viable structural material for remote three-dimensional printing using drones.
Zufferey R, Ancel AO, Farinha A, et al., 2019, Consecutive aquatic jump-gliding with water-reactive fuel, Science Robotics, Vol: 4, Pages: 1-11, ISSN: 2470-9476
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 carry out a variety of sensing tasks. One of the principal challenges in the development of such vehicles is that the transition from water to flight is a power-intensive process. At a small scale, this is made more difficult by the limitations of electromechanical actuation and the unfavorable scaling of the physics involved. This paper investigates the use of solid reactants as a combustion gas source for consecutive aquatic jump-gliding sequences. We present an untethered robot that is capable of multiple launches from the water surface and of transitioning from jetting to a glide. The power required for aquatic jump-gliding is obtained by reacting calcium carbide powder with the available environmental water to produce combustible acetylene gas, allowing the robot to rapidly reach flight speed from water. The 160-gram robot could achieve a flight distance of 26 meters using 0.2 gram of calcium carbide. Here, the combustion process, jetting phase, and glide were modeled numerically and compared with experimental results. Combustion pressure and inertial measurements were collected on board during flight, and the vehicle trajectory and speed were analyzed using external tracking data. The proposed propulsion approach offers a promising solution for future high-power density aerial-aquatic propulsion in robotics.
Zufferey R, Ancel AO, Raposo C, et al., 2019, SailMAV: Design and Implementation of a Novel Multi-Modal Flying Sailing Robot, IEEE Robotics and Automation Letters, Vol: 4, Pages: 2894-2901, ISSN: 2377-3766
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 present a new class of aerial-aquatic robot, the sailing micro air vehicle, 'SailMAV.' Thanks to a three-part folding wing design, the SailMAV is capable of both flying and sailing. The robot design permits long and targeted missions at the water interface by leveraging the wind as movement vector. It simultaneously offers the flexibility of flight for rapidly reaching a designated area, overcoming obstacles, and moving from one body of water to another, which can be very useful for water sampling in areas with many obstacles. With a total wingspan of 0.96 m, the SailMAV employs the same wing and actuation surfaces for sailing as for flying. It is capable of water surface locomotion as well as takeoff and flight at a cruising speed of 10.8 mcdots-1. The main contributions of this letter are new solutions to the challenges of combined aerial and aquatic locomotions, the design of a novel hybrid concept, the development of the required control laws, and the demonstration of the vehicle successfully sailing and taking off from the water. This letter can inform the design of hybrid vehicles that adapt their morphology to move effectively.
Armanini SF, Siddall R, Kovac M, 2019, Modelling and simulation of a bioinspired aquatic micro aerial vehicle, AIAA Aviation 2019 Forum, Publisher: American Institute of Aeronautics and Astronautics, Pages: 1-18
Zhang K, Zhu Y, Lou C, et al., 2019, A design and fabrication approach for pneumatic soft robotic arms using 3D printed origami skeletons, 2nd IEEE International Conference on Soft Robotics (RoboSoft), Publisher: IEEE, Pages: 821-827
Soft robots which employ materials with inherent compliance have demonstrated great potential in a variety of applications such as manipulators, medical tools and wearable devices. This paper presents an origami-folding inspired design and fabrication approach for developing semi-soft robotic arms. The approach starts from a conceptual design by identifying foldable origami structures. This is followed by the kinematic modelling of the selected origami skeleton with base folds of thick panels and flexible hinges. The final step realizes the design by 3D printing the skeleton and laminating the skeleton to flexible membranes on a heated vacuum table. Following the proposed approach, a foldable origami tube structure is designed, modelled and used as the exoskeleton for a pneumatic semi-soft robotic arm. Prototypes are developed by laminating a pair of 3D printed thermoplastic polyurethane (TPU) origami skeleton structures with TPU fabric film. The soft arm is actuated by a vacuum pump and its performances is evaluated through quasi-static tests. Experimental results show that the soft robotic arm achieves a maximum contraction ratio of 47.53% providing 23.463 N axial tension force when applying a regulated negative pressure of -1 bar. Two extensible and foldable pneumatic arms are integrated on a micro aerial vehicle (MAV) to obtain a platform with the potential of aerial manipulation capabilities in confined and hard to reach areas.
Hai-Nguyen N, Siddall R, Stephens B, et al., 2019, A passively adaptive microspine grapple for robust, controllable perching, 2nd IEEE International Conference on Soft Robotics (RoboSoft), Publisher: IEEE, Pages: 80-87
The application of flying systems to practical tasks is consistently limited by the poor endurance of hovering robots. The ability to perch to fixed surfaces allows a robot to gather data and inspect structures in a low power state, while retaining the access and manoeuvrability that flight offers. In this paper we present a passively adaptive perching mechanism which allows an aerial vehicle to stably attach to a variety of surfaces including tree branches and pipelines. This is enabled by a compliant grapple module, which passively conforms to the surface of convex perching targets, ensuring reliable traction and a very high load capacity (tension tested to > 60 kg in some instances) whilst still releasing effortlessly. This is due to the mechanics of the grapple, which is designed to passively tighten and attach to a variety of branch diameters and shapes. The grapple is paired with a hybrid force-motion controller which allows the cable tension to be regulated as the vehicle achieves the desired attitude. The hybrid control approach exploits the mechanical compliance of the system to ensure reliable, stable attachment to irregular natural structures, and the addition of a winch allows the robot to stably orient itself in any position or orientation relative to the branch. This approach demonstrates tensile perching using adaptive anchors. The presented subsystems can be applied to other robots where high force authority is required.
Petersen KH, Napp N, Stuart-Smith R, et al., 2019, A review of collective robotic construction, Science Robotics, Vol: 4, Pages: 1-10, ISSN: 2470-9476
The increasing need for safe, inexpensive, and sustainable construction, combined with novel technological enablers, has made large-scale construction by robot teams an active research area. Collective robotic construction (CRC) specifically concerns embodied, autonomous, multirobot systems that modify a shared environment according to high-level user-specified goals. CRC tightly integrates architectural design, the construction process, mechanisms, and control to achieve scalability and adaptability. This review gives a comprehensive overview of research trends, open questions, and performance metrics.
Chermprayong P, Zhang K, Xiao F, et al., 2019, An integrated delta manipulator for aerial repair a new aerial robotic system, IEEE Robotics and Automation magazine, Vol: 26, Pages: 54-66, ISSN: 1070-9932
Unmanned aerial vehicles (UAVs) are capable of entering hazardous areas and accessing hardto-reach locations at high altitudes. However, small-scale UAVs are inherently unstable when exposed to challenging environments. Additionally, their ability to accurately interact with infrastructure is limited by the need to stabilize the vehicle precisely in flight.
Zhang K, Chermprayong P, Tzoumanikas D, et al., 2019, Bioinspired design of a landing system with soft shock absorbers for autonomous aerial robots, Journal of Field Robotics, Vol: 36, Pages: 230-251, ISSN: 1556-4959
One of the main challenges for autonomous aerial robots is to land safely on a target position on varied surface structures in real‐world applications. Most of current aerial robots (especially multirotors) use only rigid landing gears, which limit the adaptability to environments and can cause damage to the sensitive cameras and other electronics onboard. This paper presents a bioinpsired landing system for autonomous aerial robots, built on the inspire–abstract–implement design paradigm and an additive manufacturing process for soft thermoplastic materials. This novel landing system consists of 3D printable Sarrus shock absorbers and soft landing pads which are integrated with an one‐degree‐of‐freedom actuation mechanism. Both designs of the Sarrus shock absorber and the soft landing pad are analyzed via finite element analysis, and are characterized with dynamic mechanical measurements. The landing system with 3D printed soft components is characterized by completing landing tests on flat, convex, and concave steel structures and grassy field in a total of 60 times at different speeds between 1 and 2 m/s. The adaptability and shock absorption capacity of the proposed landing system is then evaluated and benchmarked against rigid legs. It reveals that the system is able to adapt to varied surface structures and reduce impact force by 540N at maximum. The bioinspired landing strategy presented in this paper opens a promising avenue in Aerial Biorobotics, where a cross‐disciplinary approach in vehicle control and navigation is combined with soft technologies, enabled with adaptive morphology.
Tzoumanikas D, Li W, Grimm M, et al., 2019, Fully autonomous micro air vehicle flight and landing on a moving target using visual–inertial estimation and model-predictive control, Journal of Field Robotics, Vol: 36, Pages: 49-77, ISSN: 1556-4959
The Mohamed Bin Zayed International Robotics Challenge (MBZIRC) held in spring 2017 was a very successful competition well attended by teams from all over the world. One of the challenges (Challenge 1) required an aerial robot to detect, follow, and land on a moving target in a fully autonomous fashion. In this paper, we present the hardware components of the micro air vehicle (MAV) we built with off the self components alongside the designed algorithms that were developed for the purposes of the competition. We tackle the challenge of landing on a moving target by adopting a generic approach, rather than following one that is tailored to the MBZIRC Challenge 1 setup, enabling easy adaptation to a wider range of applications and targets, even indoors, since we do not rely on availability of global positioning system. We evaluate our system in an uncontrolled outdoor environment where our MAV successfully and consistently lands on a target moving at a speed of up to 5.0 m/s.
Sareh P, Chermprayong P, Emmanuelli M, et al., 2018, Rotorigami: A rotary origami protective system for robotic rotorcraft, Science Robotics, Vol: 3, ISSN: 2470-9476
Applications of aerial robots are progressively expanding into complex urban and natural environments. Despite remarkable advancements in the field, robotic rotorcraft is still drastically limited by the environment in which they operate. Obstacle detection and avoidance systems have functionality limitations and substantially add to the computational complexity of the onboard equipment of flying vehicles. Furthermore, they often cannot identify difficult-to-detect obstacles such as windows and wires. Robustness to physical contact with the environment is essential to mitigate these limitations and continue mission completion. However, many current mechanical impact protection concepts are either not sufficiently effective or too heavy and cumbersome, severely limiting the flight time and the capability of flying in constrained and narrow spaces. Therefore, novel impact protection systems are needed to enable flying robots to navigate in confined or heavily cluttered environments easily, safely, and efficiently while minimizing the performance penalty caused by the protection method. Here, we report the development of a protection system for robotic rotorcraft consisting of a free-to-spin circular protector that is able to decouple impact yawing moments from the vehicle, combined with a cyclic origami impact cushion capable of reducing the peak impact force experienced by the vehicle. Experimental results using a sensor-equipped miniature quadrotor demonstrated the impact resilience effectiveness of the Rotary Origami Protective System (Rotorigami) for a variety of collision scenarios. We anticipate this work to be a starting point for the exploitation of origami structures in the passive or active impact protection of robotic vehicles.
Sareh P, Chermprayong P, Emmanuelli M, et al., 2018, The spinning cyclic ‘Miura-oRing’ for mechanical collision-resilience, The 7th International Meeting on Origami in Science, Mathematics and Education
Jarvis R, Farinha A, Kovac M, et al., 2018, NDE sensor delivery using unmanned aerial vehicles, Insight (Northampton): non-destructive testing and condition monitoring, Vol: 60, Pages: 463-467, ISSN: 1354-2575
The robotic deployment of NDE sensors has great cost-saving potential in cases where the measurement cost is high due to access restrictions or the need to temporarily decommission the test structure. Unmanned aerial vehicles (UAVs) are able to quickly reach inaccessible components to perform visual inspection and deploy NDE sensors. In this work, a mechanical sensor release mechanism is presented that has enabled electromagnetic acoustic transducers (EMATs) to be deployed onto a ferromagnetic pipe and a plate, after which the component wall thickness measurements can be transmitted wirelessly to a remote location. The reliability of the method and the most promising areas for future development are discussed.
Goldberg B, Zufferey R, Doshi N, et al., 2018, Power and Control Autonomy for High-Speed Locomotion With an Insect-Scale Legged Robot, IEEE ROBOTICS AND AUTOMATION LETTERS, Vol: 3, Pages: 987-993, ISSN: 2377-3766
Zhang K, Chermprayong P, Alhinai TM, et al., 2017, SpiderMAV: Perching and stabilizing micro aerial vehicles with bio-inspired tensile anchoring systems, 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Publisher: IEEE, Pages: 6849-6854, ISSN: 2153-0858
Whilst Micro Aerial Vehicles (MAVs) possess a variety of promising capabilities, their high energy consumption severely limits applications where flight endurance is of high importance. Reducing energy usage is one of the main challenges in advancing aerial robot utility. To address this bottleneck in the development of unmanned aerial vehicle applications, this work proposes an bioinspired mechanical approach and develops an aerial robotic system for greater endurance enabled by low power station-keeping. The aerial robotic system consists of an multirotor MAV and anchoring modules capable of launching multiple tensile anchors to fixed structures in its operating envelope. The resulting tensile perch is capable of providing a mechanically stabilized mode for high accuracy operation in 3D workspace. We explore generalised geometric and static modelling of the stabilisation concept using screw theory. Following the analytical modelling of the integrated robotic system, the tensile anchoring modules employing high pressure gas actuation are designed, prototyped and then integrated to a quadrotor platform. The presented design is validated with experimental tests, demonstrating the stabilization capability even in a windy environment.
Sareh S, Althoefer K, Li M, et al., 2017, Anchoring like octopus: biologically inspired soft artificial sucker, Journal of the Royal Society Interface, Vol: 14, Pages: 1-9, ISSN: 1742-5662
This paper presents a robotic anchoring module, a sensorized mechanism for attachment to the environment that can be integrated into robots to enable or enhance various functions such as robot mobility, remaining on location or its ability to manipulate objects. The body of the anchoring module consists of two portions with a mechanical stiffness transition from hard to soft. The hard portion is capable of containing vacuum pressure used for actuation while the soft portion is highly conformable to create a seal to contact surfaces. The module is integrated with a single sensory unit which exploits a fibre-optic sensing principle to seamlessly measure proximity and tactile information for use in robot motion planning as well as measuring the state of firmness of its anchor. In an experiment, a variable set of physical loads representing the weights of potential robot bodies were attached to the module and its ability to maintain the anchor was quantified under constant and variable vacuum pressure signals. The experiment shows the effectiveness of the module in quantifying the state of firmness of the anchor and discriminating between different amounts of physical loads attached to it. The proposed anchoring module can enable many industrial and medical applications where attachment to environment is of crucial importance for robot control.
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