Low-pressure water hydraulics is a new branch of fluid power technology between conventional pneu... more Low-pressure water hydraulics is a new branch of fluid power technology between conventional pneumatics and hydraulics. It combines the low price level of pneumatics to the higher power density and better control of oil hydraulics. The fluid is water because it is economical, environmentally acceptable and safe to use. Low pressure level, 16...70 bar, has many advantages: existing low cost pneumatic and other industrial components can be used, piping cost is low and centrifugal pump is a suitable power source.
Proceedings of the 10th World Congress on Engineering Asset Management (WCEAM 2015), 2016
A simulation model for an oleo-pneumatic shock absorber of a combat aircraft is presented. System... more A simulation model for an oleo-pneumatic shock absorber of a combat aircraft is presented. System equations are presented incorporating the effects of friction, gas spring and damping. The model is validated with experimental data. The objective is to use the model as a tool to improve the shock absorber condition monitoring and fault detection methods. As a part of that a new measuring instrument is discussed.
Abstract Water hydraulics is both old and new technology area. The first fluid power applications... more Abstract Water hydraulics is both old and new technology area. The first fluid power applications were using water as pressure medium already in 18th-century, but the modern water hydraulics has been rapidly growing just recently in 1980's and 1990's. The main reasons for the comeback are environmental and safety aspects. Water hydraulics offers a significant alternative to establish motion control systems in environments, where possible oil leakage can cause serious problems. One of the major tasks to solve in modern water hydraulics is to achieve more accurate control systems than today`s technology provides. The present water hydraulic control valves are not yet at the same technology level as that of oil hydraulics. This means that a lot of effort has to be put to develop better and more accurate valve constructions and on the other hand more intelligent control methods has to be developed to achieve reasonable valve characteristics. This paper concentrates on a study of water hydraulic proportional valves, which are still very new developments in water hydraulics. The steady state and dynamic charateristics of water hydraulic proportional ceramic spool valve is studied both by computer simulation and laboratory tests. Some constructional improvements for the valves are studied and also different control methods are discussed and proposed.
Proceedings of the JFPS International Symposium on Fluid Power, 2002
Two simple velocity control systems of a water hydraulic motor are experimentally compared in thi... more Two simple velocity control systems of a water hydraulic motor are experimentally compared in this study; one with commercial pressure compensated proportional flow control valve and another with parallel-connected low-cost on/off solenoid valves. The aim of the study is to define suitability of these control techniques in a system where good velocity control accuracy is a significant requirement.
Water hydraulic systems use water instead of oil as a pressure medium. Microbial growth in the sy... more Water hydraulic systems use water instead of oil as a pressure medium. Microbial growth in the system may restrict the applicability this technology. The effects of fluid-flow velocity and water quality on microbial growth and biofilm formation were studied with a pilot-scale water hydraulic system. The fluid-flow velocities were 1.5-5.2 m/s and the corresponding shear stresses 9.1-84 N/m 2. The fluid-flow velocity had an insignificant effect on the total bacterial numbers and the numbers of viable heterotrophic bacteria in the pressure medium. Microbial attachment occurred under high shear stresses. The fluid-flow velocity did not affect the biofilm formation in the tank. Increase in the flow velocity decreased the bacterial densities on the pipe surfaces indicating preferable biofilm formation on areas with low flow velocity. Using ultrapure water as the pressure medium decreased the total cell numbers and resulted in slower growth of bacteria in the pressure medium. Lowering the nutrient concentration retarded biofilm formation but did not affect the final cell densities. The decreasing pressure medium nutrient concentration favoured microbial attachment in the tank instead of the pipelines. In conclusion, microbial growth and biofilm formation in water hydraulic systems cannot be controlled by the fluid-flow velocity or the quality of the pressure medium.
.  Water hydraulic systems use water as a pressure medium to minimize the adverse environmental ... more .  Water hydraulic systems use water as a pressure medium to minimize the adverse environmental impacts of oil-using hydraulics. Microbial growth in the systems may restrict the applicability of this technology. In this work, occurrence of bacteria in three different full-scale water hydraulic applications operating in different industries was studied. Bacteria were found from different parts of diesel engine direct
The effects of high and fluctuating pressure up to 220 bar on microbial growth and activity were ... more The effects of high and fluctuating pressure up to 220 bar on microbial growth and activity were determined in a pilot-scale water hydraulic system. An increase in the pipeline pressure from 70 to 220 bar decreased the total and the viable cell number in the pressure medium from 2.2(±0.5)×10 5 to 4.9(±1.5)× 10 4 cells/ml and from 5.7(±2.8)×10 4 to 1.3(±0.7)× 10 4 cfu/ml, respectively. Microbial attachment in the non-pressurised tank of the hydraulic system increased with increasing pipeline pressure [from 1.0(±0.3) to 3.8(±2.7)×10 5 cells/cm 2 on stainless steel]. The phosphatase, aminopeptidase and β-glucosidase activities in the pressurised medium were between 0.02 and 1.4 µmol/lh (V max) and decreased in response to increasing pipeline pressure. The α-glucosidase activity was detected only at 70 bar and the glucuronidase activity only occasionally. Based on principal component and cluster analyses, both the pressure applied and the original filling water quality affected ubstrate utilisation patterns. This study demonstrated the capability of freshwater bacteria to tolerate high and fluctuating pressure in a technical water system. Microbial survival was due to attachment and growth on the surfaces of the non-pressurised components and the nutrient flux released by cell lysis in the pressurised components. In summary, high pressures in water hydraulic systems do not prevent potential microbiologically related operational problems.
Global Oceans 2020: Singapore – U.S. Gulf Coast, 2020
This article studies the design, modeling, and implementation of a model-based Guidance, Navigati... more This article studies the design, modeling, and implementation of a model-based Guidance, Navigation, and Control (GNC) architecture for an Autonomous Underwater Vehicle (AUV). First, effective simulation modeling is developed using a theoretical six-degree-of-freedom (6DoF) dynamic model. Then, this study considers two GNC algorithms (simple and advanced). The simple GNC algorithm considers three different kinds of PID controllers (velocity, velocity-position, and position), and the advanced GNC algorithm enables path-following and data acquisition and processing from an underwater sensor. The path following is based on the position control using a unique PID controller and obtains its waypoints from a wall detection algorithm. This wall detection algorithm uses a mechanical imaging sonar as the main perception sensor. Finally, an implementation challenge in two control scenarios is addressed to validate the designed GNC architecture and to carry out model-verification of the position PID controller.
This article studies the design, modeling, and implementation of a path-following algorithm as a ... more This article studies the design, modeling, and implementation of a path-following algorithm as a guidance, navigation, and control (GNC) architecture for an autonomous underwater vehicle (AUV). First, a mathematical model is developed based on nonlinear equations of motion and parameter estimation techniques, including the model validation based on field test data. Then, the guidance system incorporates a line-of-sight (LOS) algorithm with a combination of position PID controllers. The GNC architecture includes a modular and multi-layer approach with an LOS-based, path-following algorithm in the AUV platform. Furthermore, the navigation used in the path-following algorithm is developed based on a predefined coverage area. Finally, this study addresses simulation and field test control scenarios to verify the developed GNC architecture.
2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
The aim of this study is to analyse the modular mechanical design and integration of all three lo... more The aim of this study is to analyse the modular mechanical design and integration of all three low-level modules in UX-1 (pendulum, ballast system and propulsion unit). The components of the perception and navigation systems have position and orientation requirements that dictate the shape of the hull. A structural strength analysis using Finite Element Method (FEM) was made to study the hull strength during deep dives. The results are presented here, which indicates that the hull endures pressures related to deep dives. Also for validation, strain gauge locations were defined.
In this article, we present a new method for describing CANopen network topology. A new format us... more In this article, we present a new method for describing CANopen network topology. A new format using GraphML, an XML-based graph format, is introduced. By using a subset of GraphML along with CANopen-specific new elements and attributes, topology of single as well as multiple CANopen networks can be captured in a well established graph format with existing tool support. The new format is specified in a manner that allows CANopen design applications to adopt it while providing a mechanism for fallback in unsupported software. Methods for extending the format to contain other CANand CANopen-specific data as well as transforming the GraphMLbased network structure to other formats are described. Finally, the implications of the introduced method and format are discussed.
2019 Third IEEE International Conference on Robotic Computing (IRC), 2019
The aim of this study is to implement a modelbased control architecture for a twin jet Unmanned S... more The aim of this study is to implement a modelbased control architecture for a twin jet Unmanned Surface Vessel (USV) using the line-of-sight (LOS) path algorithm for straight-line. The modeling and design of the motion control system are studied using MATLAB-Simulink and the real-time implementation is done by using Robot Operating System (ROS). To simplify the real-time implementation and thus, programming files, the necessary code generation is done by generating a Standalone ROS Node from Simulink software, making the process easier for researchers with non-advanced programming skills. Simulation and field test results are shown to validate the model-based control architecture.
Low-pressure water hydraulics is a new branch of fluid power technology between conventional pneu... more Low-pressure water hydraulics is a new branch of fluid power technology between conventional pneumatics and hydraulics. It combines the low price level of pneumatics to the higher power density and better control of oil hydraulics. The fluid is water because it is economical, environmentally acceptable and safe to use. Low pressure level, 16...70 bar, has many advantages: existing low cost pneumatic and other industrial components can be used, piping cost is low and centrifugal pump is a suitable power source.
Proceedings of the 10th World Congress on Engineering Asset Management (WCEAM 2015), 2016
A simulation model for an oleo-pneumatic shock absorber of a combat aircraft is presented. System... more A simulation model for an oleo-pneumatic shock absorber of a combat aircraft is presented. System equations are presented incorporating the effects of friction, gas spring and damping. The model is validated with experimental data. The objective is to use the model as a tool to improve the shock absorber condition monitoring and fault detection methods. As a part of that a new measuring instrument is discussed.
Abstract Water hydraulics is both old and new technology area. The first fluid power applications... more Abstract Water hydraulics is both old and new technology area. The first fluid power applications were using water as pressure medium already in 18th-century, but the modern water hydraulics has been rapidly growing just recently in 1980's and 1990's. The main reasons for the comeback are environmental and safety aspects. Water hydraulics offers a significant alternative to establish motion control systems in environments, where possible oil leakage can cause serious problems. One of the major tasks to solve in modern water hydraulics is to achieve more accurate control systems than today`s technology provides. The present water hydraulic control valves are not yet at the same technology level as that of oil hydraulics. This means that a lot of effort has to be put to develop better and more accurate valve constructions and on the other hand more intelligent control methods has to be developed to achieve reasonable valve characteristics. This paper concentrates on a study of water hydraulic proportional valves, which are still very new developments in water hydraulics. The steady state and dynamic charateristics of water hydraulic proportional ceramic spool valve is studied both by computer simulation and laboratory tests. Some constructional improvements for the valves are studied and also different control methods are discussed and proposed.
Proceedings of the JFPS International Symposium on Fluid Power, 2002
Two simple velocity control systems of a water hydraulic motor are experimentally compared in thi... more Two simple velocity control systems of a water hydraulic motor are experimentally compared in this study; one with commercial pressure compensated proportional flow control valve and another with parallel-connected low-cost on/off solenoid valves. The aim of the study is to define suitability of these control techniques in a system where good velocity control accuracy is a significant requirement.
Water hydraulic systems use water instead of oil as a pressure medium. Microbial growth in the sy... more Water hydraulic systems use water instead of oil as a pressure medium. Microbial growth in the system may restrict the applicability this technology. The effects of fluid-flow velocity and water quality on microbial growth and biofilm formation were studied with a pilot-scale water hydraulic system. The fluid-flow velocities were 1.5-5.2 m/s and the corresponding shear stresses 9.1-84 N/m 2. The fluid-flow velocity had an insignificant effect on the total bacterial numbers and the numbers of viable heterotrophic bacteria in the pressure medium. Microbial attachment occurred under high shear stresses. The fluid-flow velocity did not affect the biofilm formation in the tank. Increase in the flow velocity decreased the bacterial densities on the pipe surfaces indicating preferable biofilm formation on areas with low flow velocity. Using ultrapure water as the pressure medium decreased the total cell numbers and resulted in slower growth of bacteria in the pressure medium. Lowering the nutrient concentration retarded biofilm formation but did not affect the final cell densities. The decreasing pressure medium nutrient concentration favoured microbial attachment in the tank instead of the pipelines. In conclusion, microbial growth and biofilm formation in water hydraulic systems cannot be controlled by the fluid-flow velocity or the quality of the pressure medium.
.  Water hydraulic systems use water as a pressure medium to minimize the adverse environmental ... more .  Water hydraulic systems use water as a pressure medium to minimize the adverse environmental impacts of oil-using hydraulics. Microbial growth in the systems may restrict the applicability of this technology. In this work, occurrence of bacteria in three different full-scale water hydraulic applications operating in different industries was studied. Bacteria were found from different parts of diesel engine direct
The effects of high and fluctuating pressure up to 220 bar on microbial growth and activity were ... more The effects of high and fluctuating pressure up to 220 bar on microbial growth and activity were determined in a pilot-scale water hydraulic system. An increase in the pipeline pressure from 70 to 220 bar decreased the total and the viable cell number in the pressure medium from 2.2(±0.5)×10 5 to 4.9(±1.5)× 10 4 cells/ml and from 5.7(±2.8)×10 4 to 1.3(±0.7)× 10 4 cfu/ml, respectively. Microbial attachment in the non-pressurised tank of the hydraulic system increased with increasing pipeline pressure [from 1.0(±0.3) to 3.8(±2.7)×10 5 cells/cm 2 on stainless steel]. The phosphatase, aminopeptidase and β-glucosidase activities in the pressurised medium were between 0.02 and 1.4 µmol/lh (V max) and decreased in response to increasing pipeline pressure. The α-glucosidase activity was detected only at 70 bar and the glucuronidase activity only occasionally. Based on principal component and cluster analyses, both the pressure applied and the original filling water quality affected ubstrate utilisation patterns. This study demonstrated the capability of freshwater bacteria to tolerate high and fluctuating pressure in a technical water system. Microbial survival was due to attachment and growth on the surfaces of the non-pressurised components and the nutrient flux released by cell lysis in the pressurised components. In summary, high pressures in water hydraulic systems do not prevent potential microbiologically related operational problems.
Global Oceans 2020: Singapore – U.S. Gulf Coast, 2020
This article studies the design, modeling, and implementation of a model-based Guidance, Navigati... more This article studies the design, modeling, and implementation of a model-based Guidance, Navigation, and Control (GNC) architecture for an Autonomous Underwater Vehicle (AUV). First, effective simulation modeling is developed using a theoretical six-degree-of-freedom (6DoF) dynamic model. Then, this study considers two GNC algorithms (simple and advanced). The simple GNC algorithm considers three different kinds of PID controllers (velocity, velocity-position, and position), and the advanced GNC algorithm enables path-following and data acquisition and processing from an underwater sensor. The path following is based on the position control using a unique PID controller and obtains its waypoints from a wall detection algorithm. This wall detection algorithm uses a mechanical imaging sonar as the main perception sensor. Finally, an implementation challenge in two control scenarios is addressed to validate the designed GNC architecture and to carry out model-verification of the position PID controller.
This article studies the design, modeling, and implementation of a path-following algorithm as a ... more This article studies the design, modeling, and implementation of a path-following algorithm as a guidance, navigation, and control (GNC) architecture for an autonomous underwater vehicle (AUV). First, a mathematical model is developed based on nonlinear equations of motion and parameter estimation techniques, including the model validation based on field test data. Then, the guidance system incorporates a line-of-sight (LOS) algorithm with a combination of position PID controllers. The GNC architecture includes a modular and multi-layer approach with an LOS-based, path-following algorithm in the AUV platform. Furthermore, the navigation used in the path-following algorithm is developed based on a predefined coverage area. Finally, this study addresses simulation and field test control scenarios to verify the developed GNC architecture.
2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018
The aim of this study is to analyse the modular mechanical design and integration of all three lo... more The aim of this study is to analyse the modular mechanical design and integration of all three low-level modules in UX-1 (pendulum, ballast system and propulsion unit). The components of the perception and navigation systems have position and orientation requirements that dictate the shape of the hull. A structural strength analysis using Finite Element Method (FEM) was made to study the hull strength during deep dives. The results are presented here, which indicates that the hull endures pressures related to deep dives. Also for validation, strain gauge locations were defined.
In this article, we present a new method for describing CANopen network topology. A new format us... more In this article, we present a new method for describing CANopen network topology. A new format using GraphML, an XML-based graph format, is introduced. By using a subset of GraphML along with CANopen-specific new elements and attributes, topology of single as well as multiple CANopen networks can be captured in a well established graph format with existing tool support. The new format is specified in a manner that allows CANopen design applications to adopt it while providing a mechanism for fallback in unsupported software. Methods for extending the format to contain other CANand CANopen-specific data as well as transforming the GraphMLbased network structure to other formats are described. Finally, the implications of the introduced method and format are discussed.
2019 Third IEEE International Conference on Robotic Computing (IRC), 2019
The aim of this study is to implement a modelbased control architecture for a twin jet Unmanned S... more The aim of this study is to implement a modelbased control architecture for a twin jet Unmanned Surface Vessel (USV) using the line-of-sight (LOS) path algorithm for straight-line. The modeling and design of the motion control system are studied using MATLAB-Simulink and the real-time implementation is done by using Robot Operating System (ROS). To simplify the real-time implementation and thus, programming files, the necessary code generation is done by generating a Standalone ROS Node from Simulink software, making the process easier for researchers with non-advanced programming skills. Simulation and field test results are shown to validate the model-based control architecture.
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Papers by Kari Koskinen