Maarja Kruusmaa

Maarja Kruusmaa
Tallinn University of Technology | TTU · Center for Biorobotics

PhD

About

144
Publications
23,708
Reads
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2,272
Citations
Additional affiliations
January 2008 - present
Tallinn University of Technology
Position
  • Professor (Full)
Description
  • http://www.biorobotics.ttu.ee

Publications

Publications (144)
Article
Full-text available
Computational fluid dynamics (CFD) provides a powerful numerical tool to simulate and study many of the complex fluid-body interactions experienced by freshwater fish. However, major gaps remain in the application of CFD to study the fluid-body interactions of fish, including the absence of an openly available reference body geometry, the lack of a...
Preprint
Full-text available
Glacier hydrology describes water movement over, through and under glaciers and ice sheets. Water reaching the ice bed influences ice motion and ice dynamical models, therefore requiring a good understanding of glacier hydrology, particularly water pressures and pathways. However, as in situ observations are sparse and methods for direct observatio...
Article
Full-text available
Subsurface flows are challenging to map due to the inaccessibility and extreme nature. This coupled with global positioning system (GPS) denied, sensorially deprived, complex, and locally self-similar environments result in most of the traditional mapping methods failing. This results in extensive subsurface environments that remain unknown and une...
Article
Fin-actuated underwater robots usually control motion by changing the locomotion primitives of the fins, such as frequency, amplitude, phase shift, or in more complicated cases also the angle of attack. Modelling the generated thrust by an oscillating fin results in a highly non-linear model, thus making it difficult to derive a respective inverse...
Article
Vessel detection and localization based on wake measurements have been used extensively in aerial and satellite reconnaissance. Here, a wake-based approach for vessel localization and speed estimation is developed using a grid of pressure sensors on the seabed. The sensor array consisted of 9 devices in a 3 × 3 rectangular grid with 2.5 m spacing b...
Article
The lateral line system allows fish to sense the surrounding hydrodynamics via changes in the pressure, acceleration and velocity fields, providing additional information about physical habitat structure. Relations between fish and habitat preference have been traditionally inferred using the parameters of water depth, time-averaged velocity, subst...
Article
Full-text available
Sensor networks provide services to a broad range of applications ranging from intelligence service surveillance to weather forecasting. While most of the sensor networks are terrestrial, Underwater Sensor Networks (USN) are an emerging area. One of the unavoidable and increasing challenges for modern USN technology is tolerating faults, i.e., acce...
Preprint
Full-text available
Supraglacial channels constitute an important part of the glacial hydrological system, both by influencing surface energy exchange as well as routing meltwater to eventually feed en- and subglacial drainage systems. Subglacial systems have received considerable scientific interest, but specific studies of supraglacial channels are sparse. This limi...
Preprint
Full-text available
Glacial hydrology describes the way water moves over, through and under glaciers. Meltwater flows every summer over the surface of glaciers and ice sheets, creating pathways down to below the surface, eventually reaching the glacier bed and thereby influencing ice motion. Glacier and ice sheet models, trying to predict their future sea-level rise c...
Article
The design of a robust perception method is a substantial component towards achieving underwater human–robot collaboration. However, in complex environments such as the oceans, perception is still a challenging issue. Data‐fusion of different sensing modalities can improve perception in dynamic and unstructured ocean environments. This study addres...
Chapter
High-resolution (1 – 10 m) observations of supraglacial streams are needed to improve process understanding and inform low-resolution (25 – 100 m) remote sensing observations and numerical models. To address this, we built small (0.25 m diameter) satellite positioning drifters. The devices recorded the surface flow velocity, linear acceleration and...
Chapter
Academic writing courses tend to focus on rhetorical and linguistic components rather than on argument making. This is unfortunate since it is precisely the purpose of scientific writing to expose arguments. We present an attempt to overcome this divide. For the purpose, we introduce colourful argument trees that do not merely exhibit the structure...
Conference Paper
High-resolution (1-10 m) observations of supraglacial streams are needed to improve process understanding and inform low-resolution (25-100 m) remote sensing observations and numerical models. To address this, we built small (0.25 m diameter) satellite positioning drifters. The devices recorded the surface flow velocity, linear acceleration and mag...
Article
Monitoring vessel traffic in coastal regions is a key element of maritime security. For this reason, additional ways of detecting moving vessels are explored by using the unique structure of their wake waves based on pressure measurements at the seabed. The experiments are performed at a distance of about 2 km from the sailing line using novel mult...
Article
Smart environmental monitoring networks are a growing part of the Internet of Things (IoT). They are useful to detect, forecast and assess human impacts on the environment as well as the effects of climate change on society. As climate uncertainty grows, we will increasingly rely on these networks to address significant societal challenges includin...
Article
Full-text available
Glacial hydrology plays an important role in the control of glacier dynamics, of sediment transport, and of fjord and proglacial ecosystems. Surface meltwa-ter drains through glaciers via supraglacial, englacial and subglacial systems. Due to challenging field conditions, the processes driving surface processes in glacial hydrology remain sparsely...
Article
Full-text available
Animal–robot studies can inform us about animal behaviour and inspire advances in agriculture, environmental monitoring and animal health and welfare. Currently, experimental results on how fish are affected by the presence of underwater robots are largely limited to laboratory environments with few individuals and a focus on model species. Laborat...
Article
Reliable navigation of autonomous underwater vehicles (AUVs) depends on the quality of their state estimation. Providing robust velocity estimation plays thus an important role. While water currents are main contributors to the navigational uncertainty of AUVs, they are also an important variable for oceanographic research. For both reasons water c...
Article
Full-text available
This paper presents a novel design of an oscillatory fin for thrust-efficient and agile underwater robotic locomotion. We propose a flat paddle-fin comprising a set of overlapping cascaded soft flaps that open in one half of the stroke cycle and close in the other. Consequently, asymmetry in the lateral drag force exerted by the fin during oscillat...
Article
Full-text available
Artificial lateral lines are fluid flow sensor arrays, bio-inspired by the fish lateral line organ, that measure a local hydrodynamic environment. These arrays are used to detect objects in water, without relying on light, sound, or on an active beacon. This passive sensing method, called hydrodynamic imaging, is complementary to sonar and vision s...
Article
The near-bed velocity is a key physical parameter in hydrological, ecological and geomorphological studies. Considering climate change, measurement methods capable of providing continuous observations are needed to assess and predict the effects of increasing uncertainty. Therefore, a technology gap remains for continuous near-bed measurements. To...
Article
Full-text available
In recent years, flow sensing has gotten the attention of the robotics community as an exteroceptive sensing modality, in addition to the conventional underwater sensing modalities of vision and sonar. Earlier works on flow sensing for robotics focus on detection and characterization of objects’ wakes, with the focus slowly evolving towards more co...
Article
Full-text available
Lagrangian drifters are a practical way to measure natural flow features in surface channels. In this study, small cylindrical drifters (length 12 cm, diameter 4 cm) were deployed in a supraglacial channel. Each drifter recorded the total water pressure, linear acceleration, magnetic field strength and rate of rotation at 100 Hz. Based on an ensemb...
Conference Paper
Compliant fish-like robots are being developed as efficient and dependable underwater observation platforms with low impact on the observed environment. Orientation control is an essential building block to achieve autonomy for those vehicles. So far, the major focus has been on rigid tails or on flexible tails with a high degree of actuation. We p...
Article
Velocity estimation is central for the reliable navigation of autonomous underwater vehicles (AUVs). Doppler velocity logs (DVLs), currently the leading technology for underwater velocity estimation, can be too big, expensive, and energy consuming to be used on low-cost and small AUVs or for long missions. In our previous work, a system based on di...
Article
Vertical-slot fishways (VSFs) are hydraulic structures which allow fish to swim around obstacles in rivers. These structures are subject to variations in discharge of either hydrological or operational origin, which result in nonuniform water depth profiles. These profiles are manifested as differences in the water drops across the slots (ΔH) and m...
Conference Paper
Full-text available
The local flows within a fishway present a wide spectrum of hydrodynamic conditions and are themselves subject to the natural variability of the river they are connected to. Investigations of fish behavior under different flow scenarios in laboratory fishways can aid in identifying the statistically significant preferences of fish. Once patterns ha...
Article
Fish require access to multiple habitats to persist. Therefore, obstacles blocking a fish's volitional ability to move between habitats can lead to its decline. A common way of addressing this problem is the construction of fishways. The design criteria of fishways are based on steady, uniform flows with the assumption that the water levels remain...
Article
For marine industrial inspection, archaeology, and geological formation study, the ability to map unknown underwater enclosed and confined spaces is desirable and well suited for robotic vehicles. To date, there are few solutions thoroughly tested in the field designed to perform this specific task, none of which operate autonomously. With a small,...
Data
User Guide for MATLAB code and link to all measurement data: https://github.com/jtuhtan/hydro-sig
Article
The lateral line system provides fish with advanced mechanoreception over a wide range of flow conditions. Inspired by the abilities of their biological counterparts, artificial lateral lines have been developed and tested exclusively under laboratory settings. Motivated by the lack of flow measurements taken in the field which consider fluid-body...
Article
Classification of river morphology is often based on hydromorphological units (HMUs) identified from field measurements. Established survey methods rely on expert judgment or collection of field point measurements. When used for HMU classification, these methods can suffer from high errors due to the variations in the sampling environment, causing...
Article
Autonomous underwater vehicles require estimation of their velocity relative to the surrounding flow to perform essential navigation tasks. Available technologies for speed estimation rely on Doppler velocity logs or acoustic Doppler current profilers and are not suitable for application in small low cost or energy consumption vehicles. Encouraged...
Article
Global stocks of freshwater fish have been on the decline for decades, driven in part by the obstruction of their migration routes by anthropogenic barriers. To mitigate such impacts, fishways have been developed to facilitate bidirectional fish migration. These structures are affected by the hydrological variability of rivers, which can cause chan...
Article
Full-text available
U-CAT is a highly maneuverable biomimetic four-fin underwater robot for operating in confined spaces. Because of its novel mechanical design and specialized purpose, the traditional autonomous underwater robot control methods are not directly applicable on U-CAT. This paper proposes a novel modular control architecture that can be adopted for diffe...
Conference Paper
The usage of Autonomous Underwater Vehicles (AUVs) in scientific and industrial applications has increased in the last decade. In many applications the usage of fleet of heterogeneous assets is a key requirement. Their coordination and cooperation require high performance in terms of communication and information sharing. MANgO presents a federated...
Chapter
Full-text available
This chapter reflects upon Information and Communication Technologies (ICT, including informatics) research and education in the light of current technology trends. My key messages are that (1) ICT has become ubiquitous and therefore runs a risk of becoming understated and worse, underappreciated. (2) because of its widespread use ICT is evolving t...
Article
The time-averaged velocity of water flow is the most commonly measured metric for both laboratory and field applications. Its employment in scientific and engineering studies often leads to an oversimplification of the underlying flow physics. In reality, complex flows are ubiquitous, and commonly arise from fluid-body interactions with man-made st...
Article
Full-text available
Underwater robots conventionally use vision and sonar sensors for autonomous localization. Fish on the other hand also have the ability to sense flow, which assists them in navigating. Recently, it has been shown that bioinspired flow sensing can be used in robotics, for tasks such as object detection and positioning in laboratory conditions. In th...
Article
Environmental studies on fish require measurements of highly turbulent flows in both the laboratory and in the field. A fish-shaped bioinspired flow measuring device is applied in conjunction with data processing workflow which leverages the interactions between the body and the surrounding flow field for velocity estimation in turbulent flows. Our...
Conference Paper
Underwater vehicles require accurate speedometry relative to local flow conditions to perform many tasks within the aquatic environment. This paper presents preliminary results of a differential pressure sensing system using an extension of the Pitot equation capable of providing instantaneous flow speed estimation, including yaw angles from ±45º....
Conference Paper
This paper demonstrates a novel motion control approach for biomimetic underwater vehicles with pitching fins. Even though these vehicles are highly maneuverable, the actua-tion of their different degrees of freedom (DOFs) is strongly coupled. To address this problem, we propose to use smooth DOF prioritization depending on which maneuver the vehic...
Article
So far, actuated fish models have been used to study animal interactions in small-scale controlled experiments. This study, conducted in a semi-controlled setting, investigates robot⁵ interactions with a large wild-caught marine fish school (~3000 individuals) in their natural social environment. Two towed fish robots were used to decouple size, ta...
Conference Paper
Ecohydraulic studies rely on observations of fish behavior with hydrodynamic measurements. Most commonly, observed fish locations are compared with maps of the bulk flow velocity and depth. Fish use their lateral line to sense hydrodynamic interactions mediated by body-oriented spatial gradients. To improve studies on fish an artificial lateral lin...
Conference Paper
Full-text available
Fish have developed advanced hydrodynamic sensing capabilities using neuromasts, a series of collocated inertial sensors distributed over their body. We have developed the hydromast, an upscaled version of this sensing modality in order to facilitate near bed sensing for aquatic systems. Here we introduce the concept behind this bioinspired flow se...
Article
We introduce the lateral line probe (LLP) as a measurement device for natural flows. Hydraulic surveys in rivers and hydraulic structures are currently based on time-averaged velocity measurements using propellers or acoustic Doppler devices. The long-term goal is thus to develop a sensor system, which includes spatial gradients of the flow field a...
Article
Full-text available
Our aim is to improve the analysis of the force dynamics common to experimental investigations of oscillatory locomotion in underwater research. This paper proposes a new method for instationary force error modelling and correction, calibrating on a passive body at laboratory scale. The calibration function is applied to instantaneous force estimat...
Conference Paper
The scientific and civilian applications of unmanned aerial vehicles (UAVs) are rapidly expanding. The most common scientific uses are in the fields of archaeology, geography, mining, and civil engineering. Hydrosystem mapping using UAVs is both lean and agile, with the added advantage of increased safety for the surveying crew. However, a common p...
Conference Paper
Natural flows are a complex amalgam of velocity, pressure, and vorticity, which often cannot be directly measured or simulated due to their physical interdependence and scaling. Ecohydraulic investigations require not only an accurate description of the natural flow, but must also consider the fluid-body interactions between the indicator organism...
Article
Measurement of complex natural flows, especially those occurring in rivers due to man-made structures, is often hampered by the limitations of existing flow measurement methods. Furthermore, there is a growing need for new measurement devices that are capable of measuring the hydrodynamic characteristics of complex natural flows required in environ...
Article
Freshwater ecosystems are inhabited by a vast spectrum of organisms, each with their own complex biotic–abiotic relations. Considering the management and conservation of these environments, it is necessary to understand the underlying hydrodynamic interactions to which aquatic organisms are subject. Outside of bulk flow properties such as the time-...
Article
Underwater robots conventionally use vision and sonar sensors for perception purposes, but recently bio-inspired sensors that can sense flow have been developed. In literature, flow sensing has been shown to provide useful information about an underwater object and its surroundings. In the light of this, we develop an underwater landmark recognitio...
Conference Paper
Full-text available
ARchaeological RObot systems for the World's Seas (ARROWS) EU Project proposes to adapt and develop low-cost Autonomous Underwater Vehicle (AUV) Technologies to significantly reduce the cost of archaeological operations, covering the full extent of archaeological campaign. ARROWS methodology is to identify the archaeologists requirements in all pha...
Article
Full-text available
The introduction of robotic surgery within the operating rooms has significantly improved the quality of many surgical procedures. Recently, the research on medical robotic systems focused on increasing the level of autonomy in order to give them the possibility to carry out simple surgical actions autonomously. This paper reports on the developmen...
Article
For underwater vehicles to successfully detect and navigate turbulent flows, sensing the fluid interactions that occur is required. Fish possess a unique sensory organ called the lateral line. Sensory units called neuromasts are distributed over their body, and provide fish with flow-related information. In this study, a three-dimensional fish-shap...
Article
Full-text available
The trend of biomimetic underwater robots has emerged as a search for an alternative to traditional propeller-driven underwater vehicles. The drive of this trend, as in any other areas of bioinspired and biomimetic robotics, is the belief that exploiting solutions that evolution has already optimized leads to more advanced technologies and devices....
Conference Paper
This paper presents a design rationale and describes the design of a biomimetic underwater robot U-CAT. U-CAT is an autonomous, small-size and low cost vehicle, currently under development, for shipwreck penetration. The robot will assist archaeologists during possibly dangerous and expensive shipwreck exploration missions. It reduces the need of u...
Article
The present paper describes the hydrodynamic forces acting on different sized fish-shaped objects in a von Kármán vortex street, where in a wake of an object a specific locomotion pattern, Kármán gaiting, is observed. The present paper investigates the hydrodynamic forces, both lateral force and torque on a passive fish-shaped body in those hydrody...
Article
Full-text available
Background: Trends in interventional radiology and urology training are orientated towards reducing costs and increasing efficiency. In order to comply with the trends, we propose training on inexpensive patient-specific kidney phantoms. Purpose: To develop a new kidney phantom for puncture and drainage training in interventional urology and rad...
Article
For both humans and robots, tactile sensing is important for interaction with the environment: it is the core sensing used for exploration and manipulation of objects. In this paper, we present a novel tactile-array sensor based on flexible piezoresistive ...
Article
Inspired by biological swimmers such as fish, a robot composed of a rigid head, a compliant body and a rigid caudal fin was built. It has the geometrical properties of a subcarangiform swimmer of the same size. The head houses a servo-motor which actuates the compliant body and the caudal fin. It achieves this by applying a concentrated moment on a...
Article
Full-text available
The use of animals for testing and validating new medical devices and surgical techniques has raised ethical issues for a long time. Following the introduction of the Three Rs principle, significant efforts have been made to achieve a reduction in the numbers of animals used in testing. Nevertheless, the number of large animals used for testing pur...
Article
In this paper, we describe a new type of humanoid robot designed for made-to-measure garment industry — a shape-changing robotic mannequin. This mannequin is designed to imitate body shapes of different people. The main emphasis of this paper is on modeling and shape-optimization algorithm used to adjust mannequins shape to resemble the shape of an...
Conference Paper
In this paper, we present a new region based active contour algorithm for ultrasound image segmentation. An energy function based on a localized region-based active contour and shifted Rayleigh distribution is formulated. In our active contour framework, the target and background are represented as small local regions and the energy optimization is...
Conference Paper
This paper describes an underwater robot navigation strategy in flow. Our aim is to demonstrate that knowing the relative flow speed is advantageous because it permits using more energy efficient and stable control for trajectory following. We use a biomimetic robot that moves in uniform flow using a side-slipping maneuver. Side-slipping permits th...
Patent
Novel applications of electroactive polymer materials, particularly of ionic polymer metal composite (IPMC). Such applications include manipulators with combined electromechanical and electroactive actuators. Applications are particularly suitable in low gravity environment.
Article
In underwater locomotion, extracting meaningful information from local flows is as desirable as it is challenging, due to complex fluid-structure interaction. Sensing and motion are tightly interconnected; hydrodynamic signals generated by the external stimuli are modified by the self-generated flow signals. Given that very little is known about se...