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CONTROL OF A PNEUMATIC SYSTEM WITH ADAPTIVE NEURAL NETWORK COMPENSATIONTAGHIZADEH, SASAN 07 October 2010 (has links)
Considerable research has been conducted on the control of pneumatic systems due to their potential as a low-cost, clean, high power-to-weight ratio actuators. However, nonlinearities such as those due to compressibility of air continue to limit their accuracy. Among the nonlinearities in a pneumatic system, friction can have a significant effect on tracking performance, especially in applications that use rodless cylinders which have higher Coulomb friction than rodded cylinders.
Compensation for nonlinearities in pneumatic systems has been a popular area of research in pneumatic system control. Most advanced nonlinear control strategies are based on a detailed mathematical model of the system. If a simplified mathematical model is used, then performance is sensitive to uncertainties and parameter variations in the robot. Although they show relatively good results, the requirement for model parameter identification has made these methods difficult to implement. This highlights the need for an adaptive controller that is not based on a mathematical model.
The objective of this thesis was to design and evaluate a position and velocity controller for application to a pneumatic gantry robot. An Adaptive Neural Network (ANN) structure was implemented as both a controller and as a compensator. The implemented ANN had online training as this was considered to be the algorithm that had the greatest potential to enhance the performance of the pneumatic system.
One axis of the robot was used to obtain results for the cases of velocity and position control. Seven different velocity controllers were tested and their performance compared. For position control, only two controllers were examined: conventional PID and PID with an ANN Compensator (ANNC). The position controllers were tuned for step changes in the setpoint. Their performance was evaluated as applied to sinusoid tracking.
It was shown that the addition of ANN as a compensator could improve the performance of both position and velocity control. For position control, the ANNC improved the tracking performance by over 20%. Although performance was better than with conventional PID control, it was concluded that the level of improvement with ANNC did not warrant the extra effort in tuning and implementation. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-09-08 15:02:28.177
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Friluftsliv - intressant för vissa? : - En kvantitativ studie om elevers intresse för friluftsliv inom Idrott & Hälsa i skolanHöglund, Daniel January 2015 (has links)
Bakgrund Friluftsliv är något som nämns i kurs- och ämnesplanerna i Idrott & Hälsa. Trots detta kände jag att jag saknade kunskap om det under min egen skolgång vilket gjorde att jag uppfattade friluftsliv som ointressant. En del forskning har gjorts om vad man kan göra för att göra friluftsliv mer intressant för eleverna. Däremot har lite forskning gjorts angående vilka elever har/har inte ett intresse för friluftsliv. Syfte Syftet med studien är att undersöka hur intresset är för friluftsliv hos elever i årskurs 2 på gymnasiet. Finns det något samband mellan social position och intresset för friluftsliv samt skiljer sig intresset något åt mellan könen? Metod I studien har jag använt mig av en kvantitativ metod i form av enkäter. Totalt deltog 94 elever från tre skolor i Karlstads Kommun. Resultat Resultatet i studien visade på att majoriteten av eleverna tycker att friluftsliv är lite intressant samtidigt som det visade sig att ett samband fanns där ju högre social position man har, desto större intresse för friluftsliv fanns bland eleverna. Ingen större skillnad kunde ses på intresset för friluftsliv mellan könen. Diskussion Studiens resultat liknar mycket vad tidigare forskning visat. Vad som var lite anmärkningsvärt var att det visade det sig att eleverna har en ganska oklar bild om vad friluftsliv är.
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Neck Response in Out of Position Rear Impact ScenariosShateri, Hamed 25 September 2012 (has links)
Whiplash injuries occur in automotive crashes and may cause long term health issues such as headache, neck pain, and visual and auditory disturbance. Whiplash-Associated Disorders are very costly and can impair the quality of human lives. Most studies focus on whiplash injuries that occur in neutral position head postures, although there is some evidence in the literature that non-neutral head posture can significantly increase the persistence of symptoms on patients. Crash dummies have limited biofidelity particularly for out-of-position scenarios and the current neck injury criteria were not derived for situations at which the head motion is not through the sagittal plane. Therefore Finite Element Methods provide an important tool that can be used to predict injury in different impact scenarios.
The Finite Element model which was used for this study was previously developed at the University of Waterloo representing a 50th percentile male. The model had been previously validated at the segment level in extension, flexion, tension, and axial rotation. The full cervical spine model was validated in frontal and rear impact as well as tension. Since the final validation of the model, the ligament properties of the upper cervical spine and the muscle implementations had been improved to enhance the biofidelity of the model. To further improve the model, the addition of laxities to the ligaments of the upper cervical spine was studied.
Several studies were performed based on the experiments in the literature to determine appropriate laxities for the upper cervical spine model. First, the laxities of -2 to 4 mm on all the ligaments were studied on the segment level of the model to find their effect on the failure force and displacement to failure in extension, flexion, tension, and axial rotation. The model development then went through a series of iterations in order to achieve laxity values that satisfied the failure force and displacement to failure reported in the literature for the four loading cases. Finally the laxities were used on a full cervical spine model and tested in physiological range of motion in extension, flexion, axial rotation, and lateral bending. The laxities were optimized using an iterative process. The results of this study provided laxity values that were acceptable in both segments level failure study and full cervical spine physiological range of motion study.
The model was also validated against literature in impact scenarios. Using a cadaver experiment of 7 g rear impact, the global kinematics of the cervical spine was verified against the literature. The model provided good agreement with the head kinematics and relative rotations between the vertebrae for the cadaver tests. An 8 g rear impact cadaver test was used to validate the ligament strains and disc shear strains. For the anterior longitudinal ligament, the capsular ligament, and the disc shear strains, the model results were within one standard deviation of the literature in the majority of cervical spine regions that were reported. The model was also validated against volunteer low severity rear impact to verify the active musculature in the cervical spine. The head kinematics was generally within the boundaries that were reported by the literature.
The model was compared to an experiment that used cadavers to investigate non-neutral rear impact scenarios. This experiment used cables and springs to replicate the passive behaviour of the musculature. The model showed good agreement with the extension and axial rotation results in both head kinematics and relative vertebrae rotations. The flexion and lateral bending results were not similar to the experimental data; attributed to the difference in muscle implementation between the two models.
A total of 24 simulations were completed to find the effect of impact severity, axial rotation, and muscle activations on ligament strains during out-of-position rear impacts. The results illustrated that in general, ligament strains increased with the severity of impact and decreased with muscle activation. In out-of-position scenarios, the strains increased in some of the ligaments. An increase to the ligament strain as a result of non-neutral posture was mostly visible in the capsular ligaments of the upper cervical spine. The alar ligament and the apical ligaments of the upper cervical spine may fail in out-of-position at high rear impact scenarios.
Recommendations for future work on the cervical spine Finite Element model includes the validation of the musculature and the usage of the muscles to rotate the head to a desired position to improve the biofidelity of the model and the results in out-of-position rear impacts. Further optimization of the laxities of the upper cervical spine can increase the biofidelity in this region. The modeling of the vertebral arteries into the FE model can help investigate whether out-of-position can increase the chance of injury of this region. The effect of flexion, extension, lateral bending, and their combination with axial rotation and the study of frontal and side impacts can be helpful in design of safer headrests for vehicles.
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Least-Squares Based Adaptive Source Localization with Biomedical ApplicationsCamlica, Ahmet 17 April 2013 (has links)
In this thesis, we study certain aspects of signal source/target localization by sensory agents and their biomedical applications. We first focus on a generic distance measurement based problem: Estimation of the location of a signal source by a sensory agent equiped with a distance measurement unit or a team of such a sensory agent. This problem was addressed in some recent studies using a gradient based adaptive algorithm. In this study, we design a least-squares based adaptive algorithm with forgetting factor for the same task. Besides its mathematical background, we perform some simulations for both stationary and drifting target cases. The least-squares based algorithm we propose bears the same asymptotic stability and convergence properties as the gradient algorithm previously studied. It is further demonstrated via simulation studies that the proposed least-squares algorithm converges significantly faster to the resultant location estimates than the gradient algorithm for high values of the forgetting factor, and significantly reduces the noise effects for small values of the forgetting factor.
We also focus on the problem of localizing a medical device/implant in human body by a mobile sensor unit (MSU) using distance measurements. As the particular distance measurement method, time of flight (TOF) based approach involving ultra wide-band signals is used, noting the important effects of the medium characteristics on this measurement method. Since human body consists of different organs and tissues, each with a different signal permittivity coefficient and hence a different signal propagation speed, one cannot assume a constant signal propagation speed environment for the aforementioned medical localization problem. Furthermore, the propagation speed is unknown.
Considering all the above factors and utilizing a TOF based distance measurement mechanism, we use the proposed adaptive least-square algorithm to estimate the 3-D location of a medical device/implant in the human body. In the design of the adaptive algorithm, we first derive a linear parametric model with the unknown 3-D coordinates of the device/implant and the current signal propagation speed of the medium as its parameters. Then, based on this parametric model, we design the proposed adaptive algorithm, which uses the measured 3-D position of the MSU and the measured TOF as regressor signals.
After providing a formal analysis of convergence properties of the proposed localization algorithm, we implement numerical tests to analyze the properties of the localization algorithm, considering two types of scenarios: (1) A priori information regarding the region, e.g quadrant (among upper-left, upper-right, lower-left, lower-right of the human body), of the implant location is available and (2) such a priori information is not available. In (1), assuming knowledge of fixed average relative permittivity for each region, we established that the proposed algorithm converges to an estimate with zero estimation error. Moreover, different white Gaussian noises are added to emulate the TOF measurement disturbances, and it is observed that the proposed algorithm is robust to such noises/disturbances. In (2), although perfect estimation is not achieved, the estimation error is at a low admissible level.
In addition, for both cases (1) and (2), forgetting factor effects have been investigated and results show that use of small forgetting factor values reduces noise effects significantly, while use of high forgetting factor values speeds up convergence of the estimation.
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Very low frequency - Magnetic spatial position detection range and mapPoplawski, Jaroslaw January 2008 (has links)
Automated positioning systems designed to measure three-dimensional locations of objects are of paramount importance to flexible manufacturing applications. These systems should perform in an industrial environment, withstanding obstacles of solid objects and must be immune from external influences including changes in atmospheric conditions and surrounding noise. Automated positioning systems should also be free of mechanical contact and able to perform without having to establish a line-of-sight with the measured object. In this thesis, a novel design is proposed for the spatial measurement of the six degrees of freedom industrial robots and autonomous vehicles. Not only does the proposed system comply with the above characteristics, but it is also capable of achieving better resolutions than CCD cameras, easier to implement, safer than laser devices and more accurate than ultrasound systems.[...] / Doctor of Philosophy in Engineering
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Sensory interaction and motor strategies in standing in early Parkinson's disease /Smith, Rosemary Hastings. Unknown Date (has links)
Thesis (MAppSc in Physiotherapy) -- University of South Australia, 1993
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Deriving activity from RFID detection records in an assisted living context a dissertation submitted to Auckland University of Technology in partial fufilment of the requirements for the degree of Master of Computer and Information Sciences (MCIS), 2008 /Zheng, Michael. January 2008 (has links)
Thesis (MCIS - Computer and Information Sciences) -- AUT University, 2007. / Includes bibliographical references. Also held in print (xii, 126 leaves : ill. ; 30 cm.) in the Archive at the City Campus (T 621.384191 ZHE)
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Ideologie oder Pragmatismus? positions- und leistungsbasierte Sachfragen bei der Bundestagswahl 2002 im Ost-West-Vergleich /Zettl, Christian. January 2004 (has links)
Freiburg i. Br., Univ., Magisterarb., 2004.
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Socioeconomic position and the National Health Service orthodontic servicePrice, Juliet January 2016 (has links)
Background: The National Health Service (NHS) aims to achieve maximum health gains with its limited resources, while also ensuring that it provides services according to need, irrespective of factors such as socioeconomic position (SEP). Aim: The aim of this thesis is to explore the relationships between SEP and various aspects of the NHS orthodontic service, including need, demand, supply, and outcomes. Methods: Three main data sources were used: two population-based surveys (the 2003 United Kingdom (UK) Children’s Dental Health Survey (CDHS) and the 2008-2009 NHS Dental Epidemiology Programme for England Oral Health Survey (OHS) in the North West) and an administrative data set (containing 2008-2012 North West NHS orthodontic activity data). The data were used to investigate levels of need and willingness to have orthodontic treatment, treatment utilisation, assessment procedures, and treatment outcomes, and the costs associated with the service. Subsequently, regression analyses were carried out to explore the associations between SEP and the various orthodontic variables. Results: Over a third of 12-year-olds had normative need for orthodontic treatment and over half had patient-defined need. Those in the most deprived groups in the North West tended to have lower levels of treatment compared to those in the least deprived group (despite the fact that normative need was not shown to vary by SEP), and they were more likely to discontinue treatment and have residual post-treatment need (RPTN). There was a great deal of variation among practices/orthodontic clinicians in terms of the percentages of patients with repeated assessments, treatment discontinuations, and RPTN. The major sources of potential inefficiency costs in the NHS orthodontic service in the North West are treatments that result in discontinuations (which cost £2.4 million per year), RPTN (which cost £1.8 million per year), and unreported treatment outcomes (which cost £13.0 million per year). Discussion: The NHS is not delivering orthodontic care equitably between SEP groups in the North West, as those from more deprived groups are more likely to fail to receive treatment, and to have poor outcomes if they do receive treatment. In addition, the wide range of process and outcome indicators between practices/orthodontic clinicians raises issues about quality of the overall service. In particular, treatment outcomes are frequently unreported, which highlights the need to improve the outcome monitoring systems in the NHS orthodontic service.
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Ordinal Position, Family Size, and Diagnosis in a Psychiatric Hospital PopulationSensenig, John 08 1900 (has links)
The purpose of this study is to investigate the relationships between ordinal birth position, family size, and psychiatric diagnosis, in patients at a state-mental hospital.
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