Imperial College London

DrMirkoKovac

Faculty of EngineeringDepartment of Aeronautics

Reader in Aerial Robotics
 
 
 
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Contact

 

+44 (0)20 7594 5063m.kovac Website

 
 
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Location

 

326City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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58 results found

Zhang K, Chermprayong P, Tzoumanikas D, Li W, Grimm M, Smentoch M, Leutenegger S, Kovac Met 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

Journal article

Zufferey R, Ortega Ancel A, Farinha A, Siddall R, Armanini SF, Nasr M, Brahmal RV, Kennedy G, Kovac Met al., 2019, Consecutive aquatic jump-gliding with water-reactive fuel, Science Robotics, Vol: 4

Copyright © 2019 The Authors, some rights reserved; 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.

Journal article

Zufferey R, Ancel AO, Raposo C, Armanini SF, Farinha A, Siddall R, Berasaluce I, Zhu H, Kovac Met al., 2019, SailMAV: Design and Implementation of a Novel Multi-Modal Flying Sailing Robot, IEEE Robotics and Automation Letters, Vol: 4, Pages: 2894-2901

Journal article

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

Conference paper

Nguyen HN, Siddall R, Stephens B, Navarro-Rubio A, Kovac Met al., 2019, A passively adaptive microspine grapple for robust, controllable perching, Pages: 80-87

© 2019 IEEE. 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.

Conference paper

Zhang K, Zhu Y, Lou C, Zheng P, Kovac Met al., 2019, A design and fabrication approach for pneumatic soft robotic arms using 3D printed origami skeletons, Pages: 821-827

© 2019 IEEE. 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.

Conference paper

Petersen KH, Napp N, Stuart-Smith R, Rus D, Kovac Met al., 2019, A review of collective robotic construction, SCIENCE ROBOTICS, Vol: 4, ISSN: 2470-9476

Journal article

Chermprayong P, Zhang K, Xiao F, Kovac Met al., 2019, An Integrated Delta Manipulator for Aerial Repair A New Aerial Robotic System, IEEE ROBOTICS & AUTOMATION MAGAZINE, Vol: 26, Pages: 54-66, ISSN: 1070-9932

Journal article

Tzoumanikas D, Li W, Grimm M, Zhang K, Kovac M, Leutenegger Set 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.

Journal article

Sareh P, Chermprayong P, Emmanuelli M, Nadeem H, Kovac Met 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.

Journal article

Sareh P, Chermprayong P, Emmanuelli M, Nadeem, Kovac Met al., The spinning cyclic ‘Miura-oRing’ for mechanical collision-resilience, The 7th International Meeting on Origami in Science, Mathematics and Education

Conference paper

Jarvis R, Farinha A, Kovac M, Cegla Fet al., 2018, NDE sensor delivery using unmanned aerial vehicles, INSIGHT, Vol: 60, Pages: 463-467, ISSN: 1354-2575

Journal article

Goldberg B, Zufferey R, Doshi N, Helbling EF, Whittredge G, Kovac M, Wood RJet 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

Journal article

Zhang K, Chermprayong P, Alhinai TM, Siddall R, Kovac Met 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.

Conference paper

Chen Y, Wang H, Helbling EF, Jafferis NT, Zufferey R, Ong A, Ma K, Gravish N, Chirarattananon P, Kovac M, Wood RJet al., 2017, A biologically inspired, flapping-wing, hybrid aerial-aquatic microrobot, SCIENCE ROBOTICS, Vol: 2, ISSN: 2470-9476

Journal article

Sareh S, Althoefer K, Li M, Noh Y, Tramacere F, Sareh P, Mazzolai B, Kovac Met al., 2017, Anchoring like octopus: biologically inspired soft artificial sucker, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 14, ISSN: 1742-5689

Journal article

Siddall R, Kennedy G, Kovac M, 2017, High-Power Propulsion Strategies for Aquatic Take-off in Robotics, Robotics Research

Book chapter

Siddall RJD, Kovac M, Kennedy G, High Power Propulsion Strategies for Aquatic Take-off in Robotics, International Symposium on Robotics Research 2015, Publisher: Springer, ISSN: 1610-7438

The ability to move between air and water with miniature robots would allow distributedwater sampling and monitoring of a variety of unstructured marine environments,such as coral reefs and coastal areas. To enable such applications, we are developing anew class of aerial-aquatic robots, called Aquatic Micro Aerial Vehicles (AquaMAVs),capable of diving into the water and returning to flight. One of the main challenges inthe development of an AquaMAV is the provision of sufficient power density for take-offfrom the water. In this paper, we present a novel system for powerful, repeatable aquaticescape using acetylene explosions in a 34 gram water jet thruster, which expels watercollected from its environment as propellant. We overcome the miniaturisation problemsof combustible fuel control and storage by generating acetylene gas from solid calciumcarbide, which is reacted with enviromental water. The produced gas is then combusted inair in a valveless combustion chamber to produce over 20N of thrust, sufficient to propelsmall robots into the air from water. The system for producing combustible gases fromsolid fuels is a very compact means of gas storage, and can be applied to other forms ofpneumatic actuation and inflatable structure deployment.

Conference paper

Braithwaite A, Alhinai T, Haas-Heger M, McFarlane E, Kovac Met al., 2017, Spider inspired construction and perching with a swarm of nano aerial vehicles, Robotics Research, Editors: Bicchi, Burgard, Publisher: Springer, Pages: 71-88

Autonomous construction with aerial vehicles has great potential for in-situ repair and construction in hard-to-access areas. In this paper, we present and demonstrate a mechanism by which a team of autonomous nano aerial vehicles construct a multi-element tensile structure between anchor points in an irregular environment, such as a natural woodland. Furthermore, we demonstrate potential applications of such a structure to enable long-term position holding of aerial vehicles that are otherwise extremely limited in terms of available flight time due to energy constraints. To demonstrate the effectiveness of this mechanism, we develop the mechanical and electronic designs of two payload packages for attachment to nano quadrotor robots with a total integrated mass of only 26 g per robot, and we present the trajectory planning and control algorithms required to enable robust execution of the construction scheme.

Book chapter

Kovac M, Dams, Sareh, Zhang, Shepherd, Ballet al., Aerial additive building manufacturing: three-dimensional printing of polymer structures using drones, Proceedings of the Institution of Civil Engineers - Construction Materials

Conference paper

Goldberg B, Doshi N, Wood RJ, 2017, High speed trajectory control using an experimental maneuverability model for an insect-scale legged robot, 2017 IEEE International Conference on Robotics and Automation (ICRA), Publisher: IEEE

Conference paper

Sareh P, Kovac M, 2017, Robots, SCIENCE, Vol: 355, Pages: 1379-1379, ISSN: 0036-8075

Journal article

Tan YH, Siddall R, Kovac M, 2017, Efficient Aerial–Aquatic Locomotion With a Single Propulsion System, IEEE Robotics and Automation Letters, Vol: 2, Pages: 1304-1311, ISSN: 2377-3766

Aerial-aquatic locomotion would allow a broad array of tasks in robot-enabled environmental monitoring or disaster management. One of the most significant challenges of aerial-aquatic locomotion in mobile robots is finding a propulsion system that is capable of working effectively in both fluids and transitioning between them. The large differences in the density and viscosity of air compared to water means that a single direct propulsion system without adaptability will be inefficient in at least one medium. This paper examines multimodal propeller propulsion using computational tools validated against experimental data. Based on this analysis, we present a novel gearbox enabling an aerial propulsion system to operate efficiently underwater. This is achieved with minimal complexity using a single fixed pitch propeller system, which can change gear underwater by reversing the drive motor, but with the gearing arranged to leave the propeller direction unchanged. This system is then integrated into a small robot, and flights in air and locomotion underwater are demonstrated.

Journal article

Kovac M, 2017, Beyond Schrödinger's cat, Science, Vol: 355, Pages: 253-253, ISSN: 0036-8075

Journal article

Floreano D, Zufferey J-C, Klaptocz A, Germann J, Kovac Met al., 2017, Aerial Locomotion in Cluttered Environments, Editors: Christensen, Khatib, Publisher: SPRINGER-VERLAG BERLIN, Pages: 21-39, ISBN: 978-3-319-29362-2

Book chapter

Sareh S, Siddall R, Alhinai T, Kovac Met al., 2017, Bio-inspired Soft Aerial Robots: Adaptive Morphology for High-Performance Flight, Soft Robotics Week - Trends, Applications and Challenges, Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 65-74, ISSN: 2195-3562

Conference paper

Siddall R, Ancel AO, Kovac M, 2016, Wind and water tunnel testing of a morphing aquatic micro air vehicle, INTERFACE FOCUS, Vol: 7, ISSN: 2042-8898

Journal article

Siddall R, Kovac, 2016, Fast aquatic escape with a jet thruster, IEEE/ASME Transactions on Mechatronics, Vol: 22, Pages: 217-226, ISSN: 1083-4435

The ability to collect water samples rapidly with aerial–aquatic robots would increase the safety and efficiency of water health monitoring and allow water sample collection from dangerous or inaccessible areas. An aquatic micro air vehicle (AquaMAV) able to dive into the water offers a low cost and robust means of collecting samples. However, small-scale flying vehicles generally do not have sufficient power for transition to flight from water. In this paper, we present a novel jet propelled AquaMAV able to perform jumpgliding leaps from water and a planar trajectory model that is able to accurately predict aquatic escape trajectories. Using this model, we are able to offer insights into the stability of aquatic takeoff to perturbations from surface waves and demonstrate that an impulsive leap is a robust method of flight transition. The AquaMAV uses a CO 2 powered water jet to escape the water, actuated by a custom shape memory alloy gas release. The 100 g robot leaps from beneath the surface, where it can deploy wings and glide over the water, achieving speeds above 11 m/s.

Journal article

Floreano, Zufferey, Klaptocz, Germann, Kovac Met al., 2016, Aerial Locomotion in Cluttered Environments, Robotics Research, Publisher: Springer

Book chapter

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