Robert Paasch - Academia.edu (original) (raw)
Papers by Robert Paasch
Title: Towards Reliable and Survivable Ocean Wave Energy Converters
Ocean wave energy is a new and developing field of renewable energy with great potential. The ene... more Ocean wave energy is a new and developing field of renewable energy with great potential. The energy contained in one meter of an average wave off the coast of Newport Oregon could supply dozens of homes with electricity. However, ocean waves are usually quite irregular which leads to large bursts and lulls in the power available for extraction. These bursts and lulls generate large cyclic system stresses that will invariably work over time to damage an ocean wave energy converter. Due to the generally remote and extreme conditions of deployment, the reliability and survivability of an Ocean Wave Energy Converter (OWEC) are expected to greatly impact the cost of generated power passed to the consumer. For this reason, it is imperative that OWECs are both highly reliable during operation, and highly survivable through extreme conditions. This thesis is a compilation of three papers relating to the reliability and survivability of OWECs. The first paper broadly addresses the probabili...
Characterizing Dangerous Waves for Ocean Wave Energy Converter Survivability
Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms and oth... more Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms and other extreme events. In particular, high and steep waves, especially breaking waves, are likely the most dangerous to OWECs. A method for quantifying the breaking severity of waves is presented and applied to wave data from Coastal Data Information Program station 139. The data are wave height and length statistics found by conducting a zero-crossing analysis of time-series wave elevation records. Data from two of the most severe storms in the data set were analyzed. In order to estimate the breaking severity, two different steepness-based breaking criteria were utilized, one being the steepness where waves begin to show a tendency to break, the other the steepness above which waves are expected to break. Breaking severity is assigned as a fuzzy membership function between the two conditions. The distribution of breaking severity is found to be exponential. It is shown that the highest wav...
Fatigue Crack Modeling in Bridge Deck Connection Details
Many steel bridges built prior to 1960 have bridge deck connections that are subject to high cycl... more Many steel bridges built prior to 1960 have bridge deck connections that are subject to high cycle fatigue. These connections may be nearing their fatigue limit and will require increased inspection and repair over the next 10-20 years. Current inspection and repair are very expensive and only address those details which contain visible cracks. The goal of this research was to develop a methodology to identify problem details - those which are nearing the end of their serviceable life, but may not yet contain visible cracks. One Oregon bridge on Interstate 5 with this problem was studied to assess the loading conditions and fatigue crack growth rate for the connection details. The objective was to use the analysis from this bridge to develop a predictive model of connection detail fatigue life, which could be applied to other bridges. Such a model could be used to guide the inspection and repair process, significantly reducing costs. Finite element modeling methods were used to char...
Experimental Polymer Bearing Health Estimation and Test Stand Benchmarking for Wave Energy Converters
Ocean waves can provide a renewable and secure energy supply to coastal residents around the worl... more Ocean waves can provide a renewable and secure energy supply to coastal residents around the world. Yet, to safely harness and convert the available energy, issues such as bearing reliability and maintainability need to be resolved. This paper presents the application of a Prognostics and Health Management (PHM) based research methodology to derive empirical models for estimating the wear of polymer bearings installed on wave energy converters. Forming the foundation of the approach is an applicable wave model, sample data set, and experimental test stand to impose loading conditions similar to that expected in real seas. The resulting wear rates were found to be linear and stable, enabling coarse health estimations of the bearing surface.
By actively controlling the rotation of its pendulum, a vertical axis pendulum wave energy conver... more By actively controlling the rotation of its pendulum, a vertical axis pendulum wave energy converter can generate significantly more net electricity from ocean waves than what would otherwise be possible through a passively swinging pendulum. This suggests that such converters can optimize their performance by incorporating active control schemes within their ever‐ changing ocean wave environment. The challenge of implementing such control, however, necessitates that an active controller be developed. Here, we address such challenges by: (i) deriving the equations of motion for a constrained generic vertical axis pendulum wave energy converter; (ii) modeling an irregular ocean wave environment; (iii) developing a model predictive and integral error tracking controller to enforce a desired control strategy; and (iv) simulating the converter within the modeled wave environment both with and without active control for the purpose of comparing their respective net power generation resul...
In order to promote and support the wave energy industry, a Wave Energy Converter (WEC) design to... more In order to promote and support the wave energy industry, a Wave Energy Converter (WEC) design tool has been developed for modeling point absorber WECs with arbitrary device geometry. The design tool provides a numerical modeling structure and methodology capable of modeling of heaving point absorber WEC response and performance to regular and irregular operational waves. Its time-domain formulation is based on frequency-domain hydrodynamic coefficients from Boundary Element Method (BEM) codes, and provides a framework for studying WEC design and innovative control strategies.
ISOPE 2013 Presentation on WEC Modeling
Fatigue Life Distribution for a Simple Wave Energy Converter
This paper describes a computer vision approach to automated rapid-throughput taxonomic identific... more This paper describes a computer vision approach to automated rapid-throughput taxonomic identification of stonefly larvae. The long-term goal of this research is to develop a cost-effective method for environmental monitoring based on automated identification of indicator species. Recognition of stonefly larvae is challenging because they are highly articulated, they exhibit a high degree of intraspecies variation in size and color, and some species are difficult to distinguish visually, despite prominent dorsal patterning. The stoneflies are imaged via an apparatus that manipulates the specimens into the field of view of a microscope so that images are obtained under highly repeatable conditions. The images are then classified through a process that involves (a) identification of regions of interest, (b) representation of those regions as SIFT vectors [1], (c) classification of the SIFT vectors into learned "features" to form a histogram of detected features, and (d) classification of the feature histogram via state-of-the-art ensemble classification algorithms. The steps (a) to (c) compose the concatenated feature histogram (CFH) method. We apply three region detectors for part (a) above, including a newly developed principal curvature-based region (PCBR) detector. This detector finds stable regions of high curvature via a watershed segmentation algorithm. We compute a separate dictionary of learned features for each region detector, and then concatenate the histograms prior to the final classification step.
Print head apparatus with malfunction detector
Management of Uncertainty
Automated diagnosis for the time of flight scintillation array: development of a structural and behavioral reasoning system
ABSTRACT
Early Stage Failure Modeling and Analysis Applied to a Wave Energy Converter
Volume 4: 20th International Conference on Design Theory and Methodology; Second International Conference on Micro- and Nanosystems, 2008
Ocean wave power is still in its infancy. New systems are conceptualized on nearly a daily basis.... more Ocean wave power is still in its infancy. New systems are conceptualized on nearly a daily basis. The systems vary wildly in complexity and scope, but share one common trait; they have never been built. This scenario is ripe with massive financial risk and of course the possibility of reward. Providing an early stage failure and safety analysis could greatly improve the design process by identifying potential weak points in the system prior to the costly build and testing stages of product development. More broadly, determining potentially successful conceptual designs which should be pursued becomes critical. However, there is currently no tool readily available for such a task. In this paper, we adapt and simplify function-based modeling and analysis to fill this void. Completing a function based failure analysis allows engineers to evaluate the dependencies and fault tolerance of their system early in the design stage. This process aids in catching design problems when they are still relatively cheap to address. This paper proposes the System Functionality Method for conceptual design stage analysis. This proposed method places systems and subsystems in a flow (mass, energy, and signal) based on their location, and assigns functionality numbers to help describe their contribution to the system. Component or sub-system faults are then used to determine the effect on other components and the system as a whole. The process is unique in its simplicity and adaptability to the conceptual stage of designing wave energy technologies.Copyright © 2008 by ASME
Many research groups and governmental organizations, including the US Environmental Protection Ag... more Many research groups and governmental organizations, including the US Environmental Protection Agency, collect samples of insect larvae from freshwater streams to assess the health of stream ecosystems. Specimens in the samples are manually identified to the level of species or species group and counted. This is expensive, timeconsuming, and requires many years of experience. Automating this visual identification task requires highlyaccurate describes three databases of high-resolution images created to promote the development of such methods, presents benchmark results on these images, and discusses some of the issues raised for fine-grained recognition. 1.
Uncertainty Proceedings 1991, 1991
We present a general architecture for the monitoring and diagnosis of large scale sensor-based sy... more We present a general architecture for the monitoring and diagnosis of large scale sensor-based systems with real time diagnos tic constraints. This architecture is multi leveled, combining a single monitoring level based on statistical methods with two model based diagnostic levels. At each level, sources of uncertainty are identified, and integrated methodologies for uncertainty management are developed. The general architecture was applied to the monitoring and diagnosis of a specific nuclear physics detector at Lawrence Berkeley National Laboratory that contained approximately 5000 components and pro duced over 500 channels of output data. The general architecture is scalable, and work is ongoing to apply it to detector systems one and two orders of magnitude more complex.
WEC prototype advancement with consideration of a real-time damage accumulation algorithm
2011 IEEE Trondheim PowerTech, 2011
Machine maintenance and repair is not a trivial issue when it comes to renewable energy devices. ... more Machine maintenance and repair is not a trivial issue when it comes to renewable energy devices. It has been said that one of the most important factors in enhancing the marketability of wind energy is to cut its overall maintenance costs, which is about 10% - 20% of the overall cost of energy (1). The average maintenance and repair costs
Characterizing Dangerous Waves for Ocean Wave Energy Converter Survivability
29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 3, 2010
Analysis of Mechanisms for Filling Produce Containers
Transactions of the ASAE, 1981
ABSTRACT A mechanism for filling tomato trailers was developed by utilizing critical analysis of ... more ABSTRACT A mechanism for filling tomato trailers was developed by utilizing critical analysis of the design features of fillers. The filling mechanism was field tested and results indicate the effects from a single initial drop height may not be as important as that from successive multiple im-pacts as fruits bounce down a long angle of repose of fruits already in the container. Results also showed that use of the new filler reduced from 12.9 to 7.3 the percent of tomatoes in the visible loculus category.
Transactions of the ASABE, 2008
Volume 2: 29th Design Automation Conference, Parts A and B, 2003
When a complex electromechanical system fails, the troubleshooting procedure adopted is often com... more When a complex electromechanical system fails, the troubleshooting procedure adopted is often complex and tedious. No standard methods currently exist to optimize the sequence of steps in a troubleshooting process. The ad hoc methods generally followed are less than optimal methods and can result in high maintenance costs. This paper describes the use of behavioral models and multistage decision-making models in Bayesian networks for representing the troubleshooting process. It discusses advantages in using these methods and the difficulties in implementing them. An approximate method to obtain optimal decision sequence for a troubleshooting process on a complex electromechanical system is also described.
Title: Towards Reliable and Survivable Ocean Wave Energy Converters
Ocean wave energy is a new and developing field of renewable energy with great potential. The ene... more Ocean wave energy is a new and developing field of renewable energy with great potential. The energy contained in one meter of an average wave off the coast of Newport Oregon could supply dozens of homes with electricity. However, ocean waves are usually quite irregular which leads to large bursts and lulls in the power available for extraction. These bursts and lulls generate large cyclic system stresses that will invariably work over time to damage an ocean wave energy converter. Due to the generally remote and extreme conditions of deployment, the reliability and survivability of an Ocean Wave Energy Converter (OWEC) are expected to greatly impact the cost of generated power passed to the consumer. For this reason, it is imperative that OWECs are both highly reliable during operation, and highly survivable through extreme conditions. This thesis is a compilation of three papers relating to the reliability and survivability of OWECs. The first paper broadly addresses the probabili...
Characterizing Dangerous Waves for Ocean Wave Energy Converter Survivability
Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms and oth... more Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms and other extreme events. In particular, high and steep waves, especially breaking waves, are likely the most dangerous to OWECs. A method for quantifying the breaking severity of waves is presented and applied to wave data from Coastal Data Information Program station 139. The data are wave height and length statistics found by conducting a zero-crossing analysis of time-series wave elevation records. Data from two of the most severe storms in the data set were analyzed. In order to estimate the breaking severity, two different steepness-based breaking criteria were utilized, one being the steepness where waves begin to show a tendency to break, the other the steepness above which waves are expected to break. Breaking severity is assigned as a fuzzy membership function between the two conditions. The distribution of breaking severity is found to be exponential. It is shown that the highest wav...
Fatigue Crack Modeling in Bridge Deck Connection Details
Many steel bridges built prior to 1960 have bridge deck connections that are subject to high cycl... more Many steel bridges built prior to 1960 have bridge deck connections that are subject to high cycle fatigue. These connections may be nearing their fatigue limit and will require increased inspection and repair over the next 10-20 years. Current inspection and repair are very expensive and only address those details which contain visible cracks. The goal of this research was to develop a methodology to identify problem details - those which are nearing the end of their serviceable life, but may not yet contain visible cracks. One Oregon bridge on Interstate 5 with this problem was studied to assess the loading conditions and fatigue crack growth rate for the connection details. The objective was to use the analysis from this bridge to develop a predictive model of connection detail fatigue life, which could be applied to other bridges. Such a model could be used to guide the inspection and repair process, significantly reducing costs. Finite element modeling methods were used to char...
Experimental Polymer Bearing Health Estimation and Test Stand Benchmarking for Wave Energy Converters
Ocean waves can provide a renewable and secure energy supply to coastal residents around the worl... more Ocean waves can provide a renewable and secure energy supply to coastal residents around the world. Yet, to safely harness and convert the available energy, issues such as bearing reliability and maintainability need to be resolved. This paper presents the application of a Prognostics and Health Management (PHM) based research methodology to derive empirical models for estimating the wear of polymer bearings installed on wave energy converters. Forming the foundation of the approach is an applicable wave model, sample data set, and experimental test stand to impose loading conditions similar to that expected in real seas. The resulting wear rates were found to be linear and stable, enabling coarse health estimations of the bearing surface.
By actively controlling the rotation of its pendulum, a vertical axis pendulum wave energy conver... more By actively controlling the rotation of its pendulum, a vertical axis pendulum wave energy converter can generate significantly more net electricity from ocean waves than what would otherwise be possible through a passively swinging pendulum. This suggests that such converters can optimize their performance by incorporating active control schemes within their ever‐ changing ocean wave environment. The challenge of implementing such control, however, necessitates that an active controller be developed. Here, we address such challenges by: (i) deriving the equations of motion for a constrained generic vertical axis pendulum wave energy converter; (ii) modeling an irregular ocean wave environment; (iii) developing a model predictive and integral error tracking controller to enforce a desired control strategy; and (iv) simulating the converter within the modeled wave environment both with and without active control for the purpose of comparing their respective net power generation resul...
In order to promote and support the wave energy industry, a Wave Energy Converter (WEC) design to... more In order to promote and support the wave energy industry, a Wave Energy Converter (WEC) design tool has been developed for modeling point absorber WECs with arbitrary device geometry. The design tool provides a numerical modeling structure and methodology capable of modeling of heaving point absorber WEC response and performance to regular and irregular operational waves. Its time-domain formulation is based on frequency-domain hydrodynamic coefficients from Boundary Element Method (BEM) codes, and provides a framework for studying WEC design and innovative control strategies.
ISOPE 2013 Presentation on WEC Modeling
Fatigue Life Distribution for a Simple Wave Energy Converter
This paper describes a computer vision approach to automated rapid-throughput taxonomic identific... more This paper describes a computer vision approach to automated rapid-throughput taxonomic identification of stonefly larvae. The long-term goal of this research is to develop a cost-effective method for environmental monitoring based on automated identification of indicator species. Recognition of stonefly larvae is challenging because they are highly articulated, they exhibit a high degree of intraspecies variation in size and color, and some species are difficult to distinguish visually, despite prominent dorsal patterning. The stoneflies are imaged via an apparatus that manipulates the specimens into the field of view of a microscope so that images are obtained under highly repeatable conditions. The images are then classified through a process that involves (a) identification of regions of interest, (b) representation of those regions as SIFT vectors [1], (c) classification of the SIFT vectors into learned "features" to form a histogram of detected features, and (d) classification of the feature histogram via state-of-the-art ensemble classification algorithms. The steps (a) to (c) compose the concatenated feature histogram (CFH) method. We apply three region detectors for part (a) above, including a newly developed principal curvature-based region (PCBR) detector. This detector finds stable regions of high curvature via a watershed segmentation algorithm. We compute a separate dictionary of learned features for each region detector, and then concatenate the histograms prior to the final classification step.
Print head apparatus with malfunction detector
Management of Uncertainty
Automated diagnosis for the time of flight scintillation array: development of a structural and behavioral reasoning system
ABSTRACT
Early Stage Failure Modeling and Analysis Applied to a Wave Energy Converter
Volume 4: 20th International Conference on Design Theory and Methodology; Second International Conference on Micro- and Nanosystems, 2008
Ocean wave power is still in its infancy. New systems are conceptualized on nearly a daily basis.... more Ocean wave power is still in its infancy. New systems are conceptualized on nearly a daily basis. The systems vary wildly in complexity and scope, but share one common trait; they have never been built. This scenario is ripe with massive financial risk and of course the possibility of reward. Providing an early stage failure and safety analysis could greatly improve the design process by identifying potential weak points in the system prior to the costly build and testing stages of product development. More broadly, determining potentially successful conceptual designs which should be pursued becomes critical. However, there is currently no tool readily available for such a task. In this paper, we adapt and simplify function-based modeling and analysis to fill this void. Completing a function based failure analysis allows engineers to evaluate the dependencies and fault tolerance of their system early in the design stage. This process aids in catching design problems when they are still relatively cheap to address. This paper proposes the System Functionality Method for conceptual design stage analysis. This proposed method places systems and subsystems in a flow (mass, energy, and signal) based on their location, and assigns functionality numbers to help describe their contribution to the system. Component or sub-system faults are then used to determine the effect on other components and the system as a whole. The process is unique in its simplicity and adaptability to the conceptual stage of designing wave energy technologies.Copyright © 2008 by ASME
Many research groups and governmental organizations, including the US Environmental Protection Ag... more Many research groups and governmental organizations, including the US Environmental Protection Agency, collect samples of insect larvae from freshwater streams to assess the health of stream ecosystems. Specimens in the samples are manually identified to the level of species or species group and counted. This is expensive, timeconsuming, and requires many years of experience. Automating this visual identification task requires highlyaccurate describes three databases of high-resolution images created to promote the development of such methods, presents benchmark results on these images, and discusses some of the issues raised for fine-grained recognition. 1.
Uncertainty Proceedings 1991, 1991
We present a general architecture for the monitoring and diagnosis of large scale sensor-based sy... more We present a general architecture for the monitoring and diagnosis of large scale sensor-based systems with real time diagnos tic constraints. This architecture is multi leveled, combining a single monitoring level based on statistical methods with two model based diagnostic levels. At each level, sources of uncertainty are identified, and integrated methodologies for uncertainty management are developed. The general architecture was applied to the monitoring and diagnosis of a specific nuclear physics detector at Lawrence Berkeley National Laboratory that contained approximately 5000 components and pro duced over 500 channels of output data. The general architecture is scalable, and work is ongoing to apply it to detector systems one and two orders of magnitude more complex.
WEC prototype advancement with consideration of a real-time damage accumulation algorithm
2011 IEEE Trondheim PowerTech, 2011
Machine maintenance and repair is not a trivial issue when it comes to renewable energy devices. ... more Machine maintenance and repair is not a trivial issue when it comes to renewable energy devices. It has been said that one of the most important factors in enhancing the marketability of wind energy is to cut its overall maintenance costs, which is about 10% - 20% of the overall cost of energy (1). The average maintenance and repair costs
Characterizing Dangerous Waves for Ocean Wave Energy Converter Survivability
29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 3, 2010
Analysis of Mechanisms for Filling Produce Containers
Transactions of the ASAE, 1981
ABSTRACT A mechanism for filling tomato trailers was developed by utilizing critical analysis of ... more ABSTRACT A mechanism for filling tomato trailers was developed by utilizing critical analysis of the design features of fillers. The filling mechanism was field tested and results indicate the effects from a single initial drop height may not be as important as that from successive multiple im-pacts as fruits bounce down a long angle of repose of fruits already in the container. Results also showed that use of the new filler reduced from 12.9 to 7.3 the percent of tomatoes in the visible loculus category.
Transactions of the ASABE, 2008
Volume 2: 29th Design Automation Conference, Parts A and B, 2003
When a complex electromechanical system fails, the troubleshooting procedure adopted is often com... more When a complex electromechanical system fails, the troubleshooting procedure adopted is often complex and tedious. No standard methods currently exist to optimize the sequence of steps in a troubleshooting process. The ad hoc methods generally followed are less than optimal methods and can result in high maintenance costs. This paper describes the use of behavioral models and multistage decision-making models in Bayesian networks for representing the troubleshooting process. It discusses advantages in using these methods and the difficulties in implementing them. An approximate method to obtain optimal decision sequence for a troubleshooting process on a complex electromechanical system is also described.