REU Projects for Summer 2004
The following are summaries of the research projects conducted during the 2004 Metrology REU, adapted from submissions by REU participants.
Investigation of Electromagnetic Compatibility between Wireless Phones and Wireless Glucose Monitoring System
By definition, an active implant able medical device (AIMD) is a device that is inserted, partially or fully, into a human body or body cavity for permanent use by medical intervention. These devices include equipment such as pacemakers, implantable cardioverter defibrillators (ICDs), pain stimulators, respiration-stimulators, insulin or drug pumps, cochlea implants, and electrocardiogram monitors. Of particular concern are pacemakers and ICDs, which are cardiac implantable devices that treat different heart conditions. According to Faraday’s law, for any time varying magnetic field, a voltage may be induced at the input of an implanted cardiac device, thus creating a surge of excess electricity. These fields may emanate from any electronic device, such as electronic article surveillance system, weapon detectors, or high voltage overhead lines. Hospitals are now utilizing electromagnetic tracking systems during surgery as a more accurate way to view the area being operated.
A wireless probe is inserted into the patient and communicates with a base station to relay information through pulsed electromagnetic waves. Hence, these waves could possibly interfere with patients who have implantable cardiac devices if the base station is located too close to the device. The Center for the Study of Wireless Electromagnetic Compatibility at the University of Oklahoma is conducting in vitro testing to find if there is any possible interaction between implantable cardiac devices and electromagnetic tracking systems. Four questions are under consideration:
1) What degree of interaction, if any, is present between a wireless tracking system base station and various implantable cardiac devises?
2) What is a safe distance between a patient wearing an implantable cardiac device and the base station during transmission?
3) Is there a relationship in the placement of the implantable cardiac device within the body and the corresponding interaction that could occur from exposure?
4) Do some implantable cardiac devices have greater interactions with an electromagnetic tracking system than others?
By using a torso simulator, systematic testing of various degrees of interaction is possible. Due to limited research in the field of medical electromagnetic device interference, a study is warranted to investigate these issues. However, as of the writing of this report, cardiac equipment has yet to be shipped, therefore causing the delay of measurement. As a consequence, it is unwarranted to attempt any speculation on possible results. Hopefully, future research will continue with the aforementioned goals presented in consideration.
Coordinate Metrology (Flatness)
Coordinate metrology may be used to assess the quality control of manufactured parts. Flatness is one dimension of coordinate metrology that can be measured. Since nothing can be completely flat, tolerances have been set to define maximum deviations measured from an ideal flatness. Because parts need to fit in these tolerance zones, there is a great necessity for a more efficient method of sampling flatness deviations.
Currently, coordinate measuring machines used to assess quality have no set sampling methods that standardize a process to sample points. A set sampling method needs to be established to assist in standardizing data analysis and eliminating any possible human error. The main objective is to create a method of sampling, varying with size and location, which obtains the maximum amount of accurate estimates about a part at the lowest cost, considering time, for given specifications.
In this experiment, the sampling method was designed by random and aligned systematic sampling strategies and sampling sizes of 16, 64, and 256 combined specifically. The data collected from these different sampling methods was analyzed by the linear least squares method to compare results, mainly accuracy, time, and money. By using different sampling strategies to take data samples from the entire part, results were also compared to Badar’s samples over the deformed area due to manufacturing.
Once all the data was collected and entered into Excel, the flatness values for each sampling method were calculated through the fitting algorithm of linear least squares in Matlab. In all of the plate samples, aligned systematic sampling with 256 sample points produced the highest flatness value. Because the flatness value is higher, then there is more variability in the flatness of the plate that may not be detected in the lower sample point tests. Therefore, a consistent method of sampling with a large number of sampling points is necessary to accurately represent the flatness of a plate. As compared to Badar’s results, the values collected in this experiment are relatively higher. From this analysis, it can be concluded that a more representative value may be obtained by sampling the entire plate, as opposed to strictly the area around the clamps, however much more research is recommended.
Other sampling strategies should be investigated such as the Hammersley and Halton-Zaremba strategies, as well as a larger variety of sample sizes. Along with more complex sampling strategies, end-milled plates and more face-milled plates could be tested to compare flatness values. By using an automated, more complex coordinated measuring machine, more accurate results could result in much less time.
Coordinate Metrology (Complex Shapes)
Throughout industry, many companies manufacture mass-produced products. However, the products do not necessarily contain only flat surfaces. These rounded surfaces must meet specifications for production. Currently, no standard for testing the rounded surface exists. The sampling or testing must also be not only accurate but also efficient for the company. The focus of this research is to begin a data support system-one that dictates standards for measuring various types of objects. The data support system will be efficient, accurate, and repeatable.
Laser Doppler Velocimetry
Laser Doppler Velocimetry (LDV) uses a powerful laser to obtain the instantaneous velocity of a specific point within a fluid flow. Unfortunately, the LDV apparatus contains many sources of error which frequently occur because of the instrument's tremendous flexibility. Depending on the arrangement of the LDV components, materials used in testing and the time of observation, LDV can yield different velocities for an apparently identical flow. By assessing the influence of these parameters the authors of this study will determine the optimal settings for LDV measurements performed on an axis symmetric circular jet. Variables tested in this experiment include: the time-averaging interval of data samples, the flow rate through the testing apparatus, the height of the measuring volume from the nozzle exit, and the offset angle of the receiving optics .Eliminating the discrepancies between similar observations will lead to further confidence in LDV measurements.
The recorded velocity data in this study contained varying amounts of uncertainty. The overall uncertainty of velocity profiles increases as the height of the tested field increases. Greater heights correspond to a more turbulent flow. Measured values near the edges of the plume in the turbulent flow contained significantly large levels of uncertainty. Greater care and larger time-averaging intervals were necessary for turbulent flows.
For optimum efficiency, variable time-averaging should be used. Shorter time intervals can be employed at the center point of the flow and two points extending radially outward along the same axis, whereas longer intervals can be used specifically for the edges of a field. For the laminar flow, a thirty second time interval was adequate for all points in the profile except the boundary of the investigated field. Larger time averaging, however, is needed near the edge to ensure accuracy, minimize error and decrease uncertainty. Similar recommendations are justified for the turbulent flow, although the time interval must be significantly longer across the complete profile. Varying the time rate along the profile would eliminate wasted time and produce nearly identical results.
By moving the receiving optics off-axis fifteen degrees, the measuring volume was altered slightly. Recorded data contained significantly higher levels of interference than the forward scatter arrangement used predominantly in the experiment. This increased interference resulted in unreliable measurements, clearly inaccurate velocity measurements and an unintelligible velocity profile. However, increased repetition may yield data that properly reflects the velocity characteristics. The forward scatter arrangement is highly recommended unless extraneous factors limit its possibility.
Smart Structures and Transportation
Sensor technology can be used to monitor the roadways and structures to prevent safety hazards. Testing the wireless sensors and focusing on the amount of noise interference may help contribute to more accurate data being transmitted, and therefore making road condition forecasts more accurate. To understand the noise interference, it is essential to analyze the data generated through the Front Panel, the wired system unit, and the wireless sensor unit. When the data is acquired through wireless sensor unit it is plotted into a time graph. In order to compare the data acquired through sensors with the original signal, the time domain graph needs to be transformed into frequency domain.
By analyzing the PSD graph and looking at the magnitudes of different frequency components, we can easily compare the original signal with the signals from the wired and wireless sensors. In looking at the wireless and wired sensor graphs, it is apparent that there are multiple peaks throughout the graph, which indicates noise interference. When comparing the wired and wireless sensor’s graphs, the wireless sensor appeared to have more noise interference then the wired sensor. Each level of ADCs had excessive noise interference, especially in the wireless sensor. It was determined that more research is needed in the new wireless technology.
Autonomous Guided Vehicles
This research explores product development of intelligent systems as well as the structure and functions of autonomous guided vehicles. Focus has been placed in the field of robotics. The needs for robots are extensive and can be better handled by teams of robots. From mars explorations to minefield clearing, robotic teams can be used effectively in situations that may be unsafe for humans.
In order to perform sufficiently in these functions, robots must have intelligence, autonomy and the ability to work in a team. Development of these robots has to begin from the ground up and be designed to meet necessary specifications.
Five Tamiya TXT-1 Extreme R/C Monster Trucks to be used as the framework for a team of Autonomous Guided Vehicles (AGV) were built. Modifications will be made to the framework, including the addition of sensors and circuit boards.
Stand-alone Nano-indenter
Over the course of this project, the design of a free-standing nanoindenter has been sought. A design is completed that indents a sample with a prescribed force while measuring the distance that the tip of the indenter penetrates the sample. The design also provides vibration damping, three-dimensional movement, and an overview of the computer data storing program that must be devised. Piezoelectric actuators act as both the force-applying and force-measuring instruments. The data gathered from the experiment will be loaded into a computer for recording and analysis. The main factor regarding precision of the nanoindenter is the uncertainty in the stiffness of the piezoelectric actuator. At the time of publishing, the uncertainty in the stiffness is too great for the nanoindenter to be considered accurate. However, limitations of the nanoindenter have been detailed for further exploration. These include uncertainty in measuring the force, deflection of the metal pieces, and perpendicularity of the sample-indenter interface.
Lapping
Lapping is a unique finishing method in that it utilizes cutting action from loose abrasives as compared to fixed abrasives, which are used in most grinding operations. The lapping process is capable of producing high-tolerance, flat surfaces with an ultra-smooth, mirror finish. These qualities are especially desirable in valve and seal applications. To this date, little is known about the actual micro-level interactions between abrasives and workpiece material. By understanding the effects of manual lapping parameters on workpiece roughness and flatness, optimal lapping parameters can be obtained and integrated into automated systems. The effect of abrasive size and lapping time on sample roughness and uniform finish was investigated. Two sizes of 316 stainless steel samples were manually lapped with aluminum oxide abrasive paste for various lapping durations. The sample surfaces were analyzed under optical microscopes and a scanning electron microscope. Roughness measurements were taken using a mechanical profilometer. The three-inch sample discs attained a better overall surface finish than the one-inch samples. The experience and skill of the operators appears to be a significant factor in lapping. The results also suggest the need for further study of effects of workpiece weight and size of surface finish.
Business Case Analysis
The students were partitioned into teams. These teams were given the task of creating a “complete business case analysis for a phased approach to a complete, dedicated, multi-disciplined, self-sufficient laboratory over three to five years.” Each team was assigned a different type of laboratory, with the four types being: tribology laboratory, reverse engineering, CIM lab, and engineering practice field. Students were required to address current capabilities, requirements for facility, equipment, and personnel, and the cost and benefits. Laboratories proposed by the REU participants included a tribology lab, a reverse engineering lab, an engineering practice field, and a computer-integrated manufacturing lab.
The following are summaries of the research projects conducted during the 2004 Metrology REU, adapted from submissions by REU participants.
Investigation of Electromagnetic Compatibility between Wireless Phones and Wireless Glucose Monitoring System
By definition, an active implant able medical device (AIMD) is a device that is inserted, partially or fully, into a human body or body cavity for permanent use by medical intervention. These devices include equipment such as pacemakers, implantable cardioverter defibrillators (ICDs), pain stimulators, respiration-stimulators, insulin or drug pumps, cochlea implants, and electrocardiogram monitors. Of particular concern are pacemakers and ICDs, which are cardiac implantable devices that treat different heart conditions. According to Faraday’s law, for any time varying magnetic field, a voltage may be induced at the input of an implanted cardiac device, thus creating a surge of excess electricity. These fields may emanate from any electronic device, such as electronic article surveillance system, weapon detectors, or high voltage overhead lines. Hospitals are now utilizing electromagnetic tracking systems during surgery as a more accurate way to view the area being operated.
A wireless probe is inserted into the patient and communicates with a base station to relay information through pulsed electromagnetic waves. Hence, these waves could possibly interfere with patients who have implantable cardiac devices if the base station is located too close to the device. The Center for the Study of Wireless Electromagnetic Compatibility at the University of Oklahoma is conducting in vitro testing to find if there is any possible interaction between implantable cardiac devices and electromagnetic tracking systems. Four questions are under consideration:
1) What degree of interaction, if any, is present between a wireless tracking system base station and various implantable cardiac devises?
2) What is a safe distance between a patient wearing an implantable cardiac device and the base station during transmission?
3) Is there a relationship in the placement of the implantable cardiac device within the body and the corresponding interaction that could occur from exposure?
4) Do some implantable cardiac devices have greater interactions with an electromagnetic tracking system than others?
By using a torso simulator, systematic testing of various degrees of interaction is possible. Due to limited research in the field of medical electromagnetic device interference, a study is warranted to investigate these issues. However, as of the writing of this report, cardiac equipment has yet to be shipped, therefore causing the delay of measurement. As a consequence, it is unwarranted to attempt any speculation on possible results. Hopefully, future research will continue with the aforementioned goals presented in consideration.
Coordinate Metrology (Flatness)
Coordinate metrology may be used to assess the quality control of manufactured parts. Flatness is one dimension of coordinate metrology that can be measured. Since nothing can be completely flat, tolerances have been set to define maximum deviations measured from an ideal flatness. Because parts need to fit in these tolerance zones, there is a great necessity for a more efficient method of sampling flatness deviations.
Currently, coordinate measuring machines used to assess quality have no set sampling methods that standardize a process to sample points. A set sampling method needs to be established to assist in standardizing data analysis and eliminating any possible human error. The main objective is to create a method of sampling, varying with size and location, which obtains the maximum amount of accurate estimates about a part at the lowest cost, considering time, for given specifications.
In this experiment, the sampling method was designed by random and aligned systematic sampling strategies and sampling sizes of 16, 64, and 256 combined specifically. The data collected from these different sampling methods was analyzed by the linear least squares method to compare results, mainly accuracy, time, and money. By using different sampling strategies to take data samples from the entire part, results were also compared to Badar’s samples over the deformed area due to manufacturing.
Once all the data was collected and entered into Excel, the flatness values for each sampling method were calculated through the fitting algorithm of linear least squares in Matlab. In all of the plate samples, aligned systematic sampling with 256 sample points produced the highest flatness value. Because the flatness value is higher, then there is more variability in the flatness of the plate that may not be detected in the lower sample point tests. Therefore, a consistent method of sampling with a large number of sampling points is necessary to accurately represent the flatness of a plate. As compared to Badar’s results, the values collected in this experiment are relatively higher. From this analysis, it can be concluded that a more representative value may be obtained by sampling the entire plate, as opposed to strictly the area around the clamps, however much more research is recommended.
Other sampling strategies should be investigated such as the Hammersley and Halton-Zaremba strategies, as well as a larger variety of sample sizes. Along with more complex sampling strategies, end-milled plates and more face-milled plates could be tested to compare flatness values. By using an automated, more complex coordinated measuring machine, more accurate results could result in much less time.
Coordinate Metrology (Complex Shapes)
Throughout industry, many companies manufacture mass-produced products. However, the products do not necessarily contain only flat surfaces. These rounded surfaces must meet specifications for production. Currently, no standard for testing the rounded surface exists. The sampling or testing must also be not only accurate but also efficient for the company. The focus of this research is to begin a data support system-one that dictates standards for measuring various types of objects. The data support system will be efficient, accurate, and repeatable.
Laser Doppler Velocimetry
Laser Doppler Velocimetry (LDV) uses a powerful laser to obtain the instantaneous velocity of a specific point within a fluid flow. Unfortunately, the LDV apparatus contains many sources of error which frequently occur because of the instrument's tremendous flexibility. Depending on the arrangement of the LDV components, materials used in testing and the time of observation, LDV can yield different velocities for an apparently identical flow. By assessing the influence of these parameters the authors of this study will determine the optimal settings for LDV measurements performed on an axis symmetric circular jet. Variables tested in this experiment include: the time-averaging interval of data samples, the flow rate through the testing apparatus, the height of the measuring volume from the nozzle exit, and the offset angle of the receiving optics .Eliminating the discrepancies between similar observations will lead to further confidence in LDV measurements.
The recorded velocity data in this study contained varying amounts of uncertainty. The overall uncertainty of velocity profiles increases as the height of the tested field increases. Greater heights correspond to a more turbulent flow. Measured values near the edges of the plume in the turbulent flow contained significantly large levels of uncertainty. Greater care and larger time-averaging intervals were necessary for turbulent flows.
For optimum efficiency, variable time-averaging should be used. Shorter time intervals can be employed at the center point of the flow and two points extending radially outward along the same axis, whereas longer intervals can be used specifically for the edges of a field. For the laminar flow, a thirty second time interval was adequate for all points in the profile except the boundary of the investigated field. Larger time averaging, however, is needed near the edge to ensure accuracy, minimize error and decrease uncertainty. Similar recommendations are justified for the turbulent flow, although the time interval must be significantly longer across the complete profile. Varying the time rate along the profile would eliminate wasted time and produce nearly identical results.
By moving the receiving optics off-axis fifteen degrees, the measuring volume was altered slightly. Recorded data contained significantly higher levels of interference than the forward scatter arrangement used predominantly in the experiment. This increased interference resulted in unreliable measurements, clearly inaccurate velocity measurements and an unintelligible velocity profile. However, increased repetition may yield data that properly reflects the velocity characteristics. The forward scatter arrangement is highly recommended unless extraneous factors limit its possibility.
Smart Structures and Transportation
Sensor technology can be used to monitor the roadways and structures to prevent safety hazards. Testing the wireless sensors and focusing on the amount of noise interference may help contribute to more accurate data being transmitted, and therefore making road condition forecasts more accurate. To understand the noise interference, it is essential to analyze the data generated through the Front Panel, the wired system unit, and the wireless sensor unit. When the data is acquired through wireless sensor unit it is plotted into a time graph. In order to compare the data acquired through sensors with the original signal, the time domain graph needs to be transformed into frequency domain.
By analyzing the PSD graph and looking at the magnitudes of different frequency components, we can easily compare the original signal with the signals from the wired and wireless sensors. In looking at the wireless and wired sensor graphs, it is apparent that there are multiple peaks throughout the graph, which indicates noise interference. When comparing the wired and wireless sensor’s graphs, the wireless sensor appeared to have more noise interference then the wired sensor. Each level of ADCs had excessive noise interference, especially in the wireless sensor. It was determined that more research is needed in the new wireless technology.
Autonomous Guided Vehicles
This research explores product development of intelligent systems as well as the structure and functions of autonomous guided vehicles. Focus has been placed in the field of robotics. The needs for robots are extensive and can be better handled by teams of robots. From mars explorations to minefield clearing, robotic teams can be used effectively in situations that may be unsafe for humans.
In order to perform sufficiently in these functions, robots must have intelligence, autonomy and the ability to work in a team. Development of these robots has to begin from the ground up and be designed to meet necessary specifications.
Five Tamiya TXT-1 Extreme R/C Monster Trucks to be used as the framework for a team of Autonomous Guided Vehicles (AGV) were built. Modifications will be made to the framework, including the addition of sensors and circuit boards.
Stand-alone Nano-indenter
Over the course of this project, the design of a free-standing nanoindenter has been sought. A design is completed that indents a sample with a prescribed force while measuring the distance that the tip of the indenter penetrates the sample. The design also provides vibration damping, three-dimensional movement, and an overview of the computer data storing program that must be devised. Piezoelectric actuators act as both the force-applying and force-measuring instruments. The data gathered from the experiment will be loaded into a computer for recording and analysis. The main factor regarding precision of the nanoindenter is the uncertainty in the stiffness of the piezoelectric actuator. At the time of publishing, the uncertainty in the stiffness is too great for the nanoindenter to be considered accurate. However, limitations of the nanoindenter have been detailed for further exploration. These include uncertainty in measuring the force, deflection of the metal pieces, and perpendicularity of the sample-indenter interface.
Lapping
Lapping is a unique finishing method in that it utilizes cutting action from loose abrasives as compared to fixed abrasives, which are used in most grinding operations. The lapping process is capable of producing high-tolerance, flat surfaces with an ultra-smooth, mirror finish. These qualities are especially desirable in valve and seal applications. To this date, little is known about the actual micro-level interactions between abrasives and workpiece material. By understanding the effects of manual lapping parameters on workpiece roughness and flatness, optimal lapping parameters can be obtained and integrated into automated systems. The effect of abrasive size and lapping time on sample roughness and uniform finish was investigated. Two sizes of 316 stainless steel samples were manually lapped with aluminum oxide abrasive paste for various lapping durations. The sample surfaces were analyzed under optical microscopes and a scanning electron microscope. Roughness measurements were taken using a mechanical profilometer. The three-inch sample discs attained a better overall surface finish than the one-inch samples. The experience and skill of the operators appears to be a significant factor in lapping. The results also suggest the need for further study of effects of workpiece weight and size of surface finish.
Business Case Analysis
The students were partitioned into teams. These teams were given the task of creating a “complete business case analysis for a phased approach to a complete, dedicated, multi-disciplined, self-sufficient laboratory over three to five years.” Each team was assigned a different type of laboratory, with the four types being: tribology laboratory, reverse engineering, CIM lab, and engineering practice field. Students were required to address current capabilities, requirements for facility, equipment, and personnel, and the cost and benefits. Laboratories proposed by the REU participants included a tribology lab, a reverse engineering lab, an engineering practice field, and a computer-integrated manufacturing lab.
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