En la presente investigación se determinó el efecto de la aplicación de condensadores en el control de pérdidas de motores trifásicos en la Sociedad Minera Austria Duvaz SAC, evaluando diversos aspectos relacionados al estator y rotor. Para el desarrollo de esta investigación resultó necesario desarrollar un diseño experimental, pues se observó las pérdidas generadas sin (evaluación previa) y con (evaluación posterior) la implementación de los condensadores a un total de 38 motores trifásicos dentro de la Unidad Económica Activa Morococha. Los resultados señalan que se encontró que los motores no venían trabajando eficientemente, pues su factor de potencia se encontró FP = Cosφ = 0,75 promedio, un valor muy por debajo del nivel de eficiencia para un funcionamiento adecuado. La aplicación de condensadores fue diseñado para alcanzar un factor de potencia igual a 0,95, es así que se logró reducir las pérdidas de potencia activa de 961.86 kW a 605.71 kW. Asimismo se redujo la corriente en 21%; mientras que la variación de las pérdidas se situó en un 37.7% por debajo de lo inicial, después de la corrección de pérdidas con condensadores. Se concluye que el uso de condensadores reduce significativamente las pérdidas de motores trifásicos ahorrando un total de 147,249 KVAR - mes y más de S/ 7.0 mil mensuales en la facturación.

[Tuncated abstract] Previous research has shown that associated movements (AMs) decrease with age in typically developing children. However, considerable variability has been found to exist between children of the same chronological age (Wolff et al., 1983; Largo et al., 2001) and the reasons for this variability are unclear. As AMs are considered to be a construct of motor behaviour it is possible that varying levels of motor ability may contribute to this variability. Only a few studies have investigated the relationship between motor ability and AM expression, and those have resulted in equivocal findings. Therefore, the aim of the first study in this research project was to investigate the relationship between motor ability and AMs using a large sample of normative children (N=165). Group 1 consisted of 19 boys and 33 girls in school year 1 with a mean age of 6 years and 4 months (SD = 4 months); Group 2 consisted of 28 boys and 29 girls in school year 3 with a mean age of 8 years and 3 months (SD = 3 months); and Group 3 consisted of 27 boys and 29 girls in school year 5 with a mean age of 9 years 11 months (SD = 5 months). Motor ability was established using the McCarron Assessment of Neuromuscular Development (MAND) (McCarron, 1982). Associated movements were measured using tasks adapted from the Zurich Neuromotor Assessment (Largo et al., 2002), the Fog Test (Fog & Fog, 1963), and Licari et al. (2006). '...' The second study in this research project continued to explore the relationship between motor ability and AMs by investigating whether increased severity of AMs previously reported in children with attention deficit hyperactivity disorder (ADHD) (Denckla & Rudel, 1978; Lazarus, 1994; Mostofsky et al., 2003) is reflective of symptoms associated with the disorder or movement difficulties co-occurring in some children with the disorder. Four groups of children participated in the study. Group 1 consisted of 13 children with Developmental Coordination Disorder (DCD) with a mean age of 7 years 3 months (SD = 9 months); Group 2 consisted of 13 children with ADHD with a mean age of 7 years 4 months (SD = 11 months); Group 3 consisted of 10 children with co-occurring DCD and ADHD with a mean age of 7 years 4 months (SD = 10 months); and, Group 4 was a normative sample 15 control children. The children undertook the same AM assessment protocol outlined for Study 1. The AM data was entered into the RUMM 2020 and person location estimates (Rasch AM scores) were created for each child based on the person location map from Study 1. A comparison of AM scores between the groups revealed that the DCD and DCD/ADHD groups showed significantly more (p <0.001) AMs than the children in the ADHD and control groups. No significant differences were found between children in the DCD and DCD/ADHD groups (p = 0.19) or the ADHD and control groups (p = 0.67). The findings of this research show that increased expression of AMs is not influenced by the symptoms of ADHD. In addition, the finding that increased expression of AMs in children with DCD extends the findings from Study 1 showing that AM expression is linked to motor ability. Overall this research has enhanced the understanding of a unique measure of motor behaviour.

The goal of this thesis is to apply the computational approach to motor learning, i.e., describe the constraints that enable performance improvement with experience and also the constraints that must be satisfied by a motor learning system, describe what is being computed in order to achieve learning, and why it is being computed. The particular tasks used to assess motor learning are loaded and unloaded free arm movement, and the thesis includes work on rigid body load estimation, arm model estimation, optimal filtering for model parameter estimation, and trajectory learning from practice. Learning algorithms have been developed and implemented in the context of robot arm control. The thesis demonstrates some of the roles of knowledge in learning. Powerful generalizations can be made on the basis of knowledge of system structure, as is demonstrated in the load and arm model estimation algorithms. Improving the performance of parameter estimation algorithms used in learning involves knowledge of the measurement noise characteristics, as is shown in the derivation of optimal filters. Using trajectory errors to correct commands requires knowledge of how command errors are transformed into performance errors, i.e., an accurate model of the dynamics of the controlled system, as is demonstrated in the trajectory learning work. The performance demonstrated by the algorithms developed in this thesis should be compared with algorithms that use less knowledge, such as table based schemes to learn arm dynamics, previous single trajectory learning algorithms, and much of traditional adaptive control.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: James C. Galloway, Dept. of Physical Therapy. Includes bibliographical references.

Variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices. In this study, a three phase induction motor drive using Insulated Gate Bipolar Transistors (IGBT) at the inverter power stage is introduced to implement speed and position control for the revolving stage in the Frederic Wood Theatre This thesis presents a solution to control a 3-phase induction motor using the Texas Instruments (TI) Digital Signal Processor (DSP) TMS320F2407A. The use of this DSP yields enhanced operations, fewer system components, lower system cost and increased efficiency. The control algorithm is based on the constant volts-per-hertz principle because the exact speed control is not needed. Reflective object sensors which are mounted on concrete frame are used to detect accurate edge position of revolving stage. The sinusoidal voltage waveforms are generated by the DSP using the space vector modulation technique. In order to satisfy some operating conditions for safe and agreeable operation, a look-up table, which is used to give command voltage and speed signals in software, is applied to limit the maximum speed and acceleration of the revolving stage. Meanwhile, a boost voltage signal is added at the low frequency areas to make the motor produce maximum output torque when starting. A test prototype is then built to validate the performance. Several tests are implemented into the IGBT drive to explore the reason for unacceptable oscillations in IGBT’s gate control signals. Improvement methods in hardware layout are suggested for the final design.

Saab has an analogue solution which is used to drive small motors in aircrafts. The motor is a brushless DC-motor and uses a resolver and hall sensors to control it. As sensorless control is something that has been expanding and attracting more interest over the last decade, Saab is considering the possibility of using a digital sensorless system depending on its performance on the control compared to their analogue system. There is little documentation of performance for a digital sensorless solution compared to an analogue solution. Therefore the question to be answered in this research is: How is the performance of the digital solution compared to the existing analogue solution? It was answered by finding a complete sensorless system on the market and then compare its performance to a digital system with sensors that resembles the analogue solution. Performance wise, InstaSPIN does not perform as well as EPOS2 which represent the sensorless system respective the system with sensors. InstaSPIN needs a startup sequence, can not run at the same low velocities, has a longer rise time, settling time and greater ripple. An examination of the software should be done before using the disadvantages that was found as a reason for not considering a sensorless system. Especially the startup sequence in the software should be examined as it is InstaSPINs greatest weakness compared to EPOS2. / Saab använder idag ett analogt system för att driva små motorer i deras flygfarkoster. Det analoga systemet använder en borstlös DC-motor och en resolver för styrning av motorn. Motorstyrning med system som är oberoende av givare är ett område som vuxit och fått ett ökat intresse det senaste decenniet. Saab överväger möjligheten att använda ett givarlöst digitalt system beroende på dess styrprestanda jämfört med deras analoga system. Eftersom det finns lite dokumentation om prestandan så är frågan som ska besvaras i denna rapport: Hur förhåller sig det givarlösa digitala systemet prestandamässigt jämfört med det existerande analoga systemet? Detta besvarades genom att leta upp ett komplett system på marknaden och sedan jämföra dess prestanda mot ett digitalt system som liknar det analoga systemet.  Prestandamässigt så fungerar InstaSPIN som representerar det givarlösa systemet inte lika effektivt som EPOS2 som representerar systemet som använder givare. Nackdelarna med InstaSPIN är att den behöver en startsekvens, inte kan köra på lika låga hastigheter, har längre stigtid, insvängningstid och större rippel. Man bör undersöka mjukvaran innan nackdelarna används som en anledning till att inte använda ett givarlöst system. Speciellt startsekvensen bör undersökas eftersom det är IntaSPINs största svaghet jämfört mot EPOS2.

This thesis reports on a multi-phased research project conducted to evaluate the use of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach with adults with stroke. Current approaches to motor recovery, called systems approaches, suggest that movement arises from a dynamic interaction among several different systems, including perception, cognition, and action, all within the context of the individual and his or her environment. CO-OP is an established treatment approach for children with motor-based performance problems that takes into account interactions among several systems, as well as individual needs and environmental factors. CO-OP is a client-centred, problem solving approach based on the theoretical foundations of learning and motor learning theory. The objectives of this project were: to examine the efficacy of CO-OP to improve motor skill acquisition and performance in adults living with chronic stroke; to explore other benefits of the approach; and to identify adaptations for use with adults with stroke. Two series of single case experimental studies were conducted, with three participants completing each. In addition, semi-structured interviews were conducted. Findings from the single case experiments provide evidence that CO-OP is associated with performance improvements in both trained and untrained self-selected goals in adults more than one year post stroke. As well, pre-post measures suggest there may be changes in performance satisfaction, motor control, generalized use of the affected upper extremity, and self-efficacy. Interview findings provided valuable information about the experiences of participants with the approach; the interview respondents enjoyed the increased sense of responsibility that came with problem solving on their own, but expressed a desire to have ongoing professional support. Suggestions for modifications to CO-OP for use adults with stroke are made. CO-OP is a promising approach to improve functional independence in adults with stroke. Future research is warranted.

Increasing evidence supports the use of physical activity for modifying brain activity and overall neurological health (Hillman et al, 2008). Specifically, aerobic exercise appears to improve cognitive efficacy with regards to decisional oddball tasks shown through the P300, whose amplitude and latency is augmented (Magnié et al., 2000). Furthermore, the effects of an acute bout of aerobic exercise on cardiovascular function are well established and are sustained following exercise cessation. Based on these findings, we proposed that (1) an acute bout of exercise may modulate movement-related cortical excitability within motor areas and (2) that transient effects would be sustained as long as heart rate (HR) remained elevated. Subjects (n=23) were placed in a soundproof booth and instructed to perform a self-paced unimanual ballistic wrist extension every 3-6 seconds of the right wrist while holding a moveable handle. The motion involved a brisk contraction followed by relaxation and positional reset, collected continuously for approximately 8 minutes. Electroencephalography was used to measure movement-related cortical activity of the Bereitschaftspotential (BP) time-locked to onset of muscle activity associated with movement. The BP is a slow negative self-paced movement related cortical potential that precedes movement by approximately 1500ms. Current work commonly separates the BP into 3 main components early, late, and re-afferent Potentials. The early BP is representative of motor preparation of supplementary motor area (SMA) activity while the late component is representative of motor execution from primary motor cortex (M1). Early and late components are often distinguished by a a characteristic change in slope; where the early BP is a slow negative rise and the late components a steeper negative deflection beginning approximately 500ms prior to movement onset. Broken down further the late component consists of a portion of negative slope before giving rise to a peak approximately 100ms after movement onset known as the motor potential (MP). Following baseline measures, subjects performed 20 minutes of aerobic exercise at a moderate intensity (70% of age-predicted maximum heart rate) on a recumbent cycle ergometer. After the cessation of exercise, BP measures were recorded at two time points: immediately post-exercise (Post) and following a return to iv baseline HR (Post[Rest]) and two additional measures separated by 15 minutes each (Post[Rest2] and Post[Rest3]) which was, on average, 45 minutes after the cessation of exercise. Electromyography (EMG) was employed over the extensor carpi radialis muscle belly to describe muscle burst activity and onset characteristics. Results determined that Early but not Late BP was influenced by aerobic exercise. This early movement related cortical adaptation is indicative of enhanced processing within supplementary motor area. Moreover, this effect was sustained for up to an hour and 15 minutes following exercise cessation. This data is suggestive that aerobic exercise influences on motor related cortical excitability is not driven by an aerobic exercise effect and is more indicative of a delayed neurotransmitter effect.

This study compared the effects of two conditions on the motor development of preschool children and investigated the relationship between preschool children's motor development and perceived competence. Specifically, it provided information for discerning: a) the relative effects of a sensory-motor condition and an unstructured activities condition on the motor development of preschool children immediately following the 20-week intervention; and b) whether perceived competence was related to motor development in the preschool children following termination of the treatment. Additionally, a teacher survey which addressed the teacher-consultant relationship was developed and piloted within the context of the study for use in future research. Subjects were 31 children enrolled in two preschool programs including: a) the curriculum group (N=16), and b) the non-curriculum group (N=l5). The Peabody Motor Developmental Scales and the Pictorial Scale of Perceived Competence and Social Acceptance were used to assess the children's motor development and perceived competence, respectively. All subjects were tested prior to the 20- week intervention period and immediately following the intervention. A series of 2 (group) X 2 (testing time) repeated measures analyses of variance were used to analyze the impact of the two conditions. Results revealed that the motor development of subjects in both groups changed significantly over time; however, there were no differences between groups. Product-moment correlations and linear regression analyses were used to assess the relationship between preschool children's motor development and perceived competence. Results revealed that perceived competence relative to motor development did not change over time; however a reciprocal relationship between motor development and perceived competence in preschool children was found. The piloted teacher survey showed potential for evaluation of service delivery models and as a tool for teacher-consultant communication in future studies. / Graduation date: 1991

This thesis reports on a multi-phased research project conducted to evaluate the use of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach with adults with stroke. Current approaches to motor recovery, called systems approaches, suggest that movement arises from a dynamic interaction among several different systems, including perception, cognition, and action, all within the context of the individual and his or her environment. CO-OP is an established treatment approach for children with motor-based performance problems that takes into account interactions among several systems, as well as individual needs and environmental factors. CO-OP is a client-centred, problem solving approach based on the theoretical foundations of learning and motor learning theory. The objectives of this project were: to examine the efficacy of CO-OP to improve motor skill acquisition and performance in adults living with chronic stroke; to explore other benefits of the approach; and to identify adaptations for use with adults with stroke. Two series of single case experimental studies were conducted, with three participants completing each. In addition, semi-structured interviews were conducted. Findings from the single case experiments provide evidence that CO-OP is associated with performance improvements in both trained and untrained self-selected goals in adults more than one year post stroke. As well, pre-post measures suggest there may be changes in performance satisfaction, motor control, generalized use of the affected upper extremity, and self-efficacy. Interview findings provided valuable information about the experiences of participants with the approach; the interview respondents enjoyed the increased sense of responsibility that came with problem solving on their own, but expressed a desire to have ongoing professional support. Suggestions for modifications to CO-OP for use adults with stroke are made. CO-OP is a promising approach to improve functional independence in adults with stroke. Future research is warranted.