Bioengineering of exercise: biomechanical and metabolic aspects

The field of research of this dissertation concerns the bioengineering of exercise, in particular the relationship between biomechanical and metabolic knowledge. This relationship can allow to evaluate exercise in many different circumstances: optimizing athlete performance, understanding and helping compensation in prosthetic patients and prescribing exercise with high caloric consumption and minimal joint loading to obese subjects. Furthermore, it can have technical application in fitness and rehabilitation machine design, predicting energy consumption and joint loads for the subjects who will use the machine. The aim of this dissertation was to further understand how mechanical work and metabolic energy cost are related during movement using interpretative models. Musculoskeletal models, when including muscle energy expenditure description, can be useful to address this issue, allowing to evaluate human movement in terms of both mechanical and metabolic energy expenditure. A whole body muscle-skeletal model that could describe both biomechanical and metabolic aspects during movement was identified in literature and then was applied and validated using an EMG-driven approach. The advantage of using EMG driven approach was to avoid the use of arbitrary defined optimization functions to solve the indeterminate problem of muscle activations. A sensitivity analysis was conducted in order to know how much changes in model parameters could affect model outputs: the results showed that changing parameters in between physiological ranges did not influence model outputs largely. In order to evaluate its predicting capacity, the musculoskeletal model was applied to experimental data: first the model was applied in a simple exercise (unilateral leg press exercise) and then in a more complete exercise (elliptical exercise). In these studies, energy consumption predicted by the model resulted to be close to energy consumption estimated by indirect calorimetry for different intensity levels at low frequencies of movement. The use of muscle skeletal models for predicting energy consumption resulted to be promising and the use of EMG driven approach permitted to avoid the introduction of optimization functions. Even though many aspects of this approach have still to be investigated and these results are preliminary, the conclusions of this dissertation suggest that musculoskeletal modelling can be a useful tool for addressing issues about efficiency of movement in healthy and pathologic subjects.

Development of a grid connected micro wind generator. A practical activity for the course on electric generation with wind energy

This paper describes a practical activity, part of the renewable energy course where the students have to build their own complete wind generation system, including blades, PM-generator, power electronics and control. After connecting the system to the electric grid the system has been tested during real wind scenarios. The paper will describe the electric part of the work surface-mounted permanent magnet machine design criteria as well as the power electronics part for the power control and the grid connection. A Kalman filter is used for the voltage phase estimation and current commands obtained in order to control active and reactive power. The connection to the grid has been done and active and reactive power has been measured in the system.

Die Maschinen-Elemente, ihre Berechnung und Konstruktion mit Rücksicht auf die neuern Versuche,

Bibliographical footnotes.

Technical data on Soviet heavy machinery.

"CSO DC-1942."

The experimental stress analysis of the Firestone type R-5⁰, 20 x 75 truck rim.

Vols. 2-3 have title: The experimental stress analysis of truck rims.

Cyclopedia of drawing.

-[pt. I] Mechanical drawing, by E. Kenison. Shades and shadows, by H. W. Gardner. Perspective drawing, by W. H. Lawrence. Freehand drawing, by H.E. Everett. Pen and ink rendering, by D. A. Gregg. Rendering in wash, by H. V. von Holst. Architectural lettering, by F. C. Brown.- [pt. 2] - Mechanical drawing, by E. Kenison. Working drawings, machine design, by C. L. Griffin. Sheet metal pattern drafting, tinsmithing, practical problems in mensuration, by W. Neubecker.

Engineering applications of higher mathematics,

Bibliography at end of each volume.

Machinery and production engineering.

Latest issue consulted: Vol. 160, no. 4059 (20 Sept. 2002).

Compendium of drawing ...

[pt.I] Mechanical drawing, by E. Kenison. Shades and shadows, by H. W. Gardner. Perspective drawing, by W. H. Lawrence. Pen and ink rendering, by D. A. Gregg. Architectural lettering, by F. C. Brown.-- pt.II Working drawings, by C. L. Griffin. Mechanism [by] W. H. James. Machine design, by C. L. Griffin. Sheet metal pattern drafting, tin-smithing, by W. Neubecker.

The graphical statics of mechanism. A guide for the use of machinists, architects, and engineers; and also a textbook for technical schools.

Translation of Zur graphischen Statik der Maschinengetriebe.

Sammlung von zeichungen für die Hütte. Norizen

Mode of access: Internet.

Theatri machinarvm erster[-sechster] Theill : in welchem vilerley künstliche Machinae in vnterschidlichen Kupfferstücken zu sehen sindt ... /

Some plates by Andreas Bretschneider. Others by or after Henning Grossen, and some after Heinrich Zeising.

Vibration control

Mode of access: Internet.

Flexible high speed machinery

The thesis describes an investigation into methods for the design of flexible high-speed product processing machinery, consisting of independent electromechanically actuated machine functions which operate under software coordination and control. An analysis is made of the elements of traditionally designed cam-actuated, mechanically coupled machinery, so that the operational functions and principal performance limitations of the separate machine elements may be identified. These are then used to define the requirements for independent actuators machinery, with a discussion of how this type of design approach is more suited to modern manufacturing trends. A distributed machine controller topology is developed which is a hybrid of hierarchical and pipeline control. An analysis is made, with the aid of dynamic simulation modelling, which confirms the suitability of the controller for flexible machinery control. The simulations include complex models of multiple independent actuators systems, which enable product flow and failure analyses to be performed. An analysis is made of high performance brushless d.c. servomotors and their suitability for actuating machine motions is assessed. Procedures are developed for the selection of brushless servomotors for intermittent machine motions. An experimental rig is described which has enabled the actuation and control methods developed to be implemented. With reference to this, an evaluation is made of the suitability of the machine design method and a discussion is given of the developments which are necessary for operational independent actuators machinery to be attained.

Projeto iterativo, simulação, análise e otimização de máquina a relutância variável monofásica

Variable reluctance motors have been increasingly used as an alternative for variable speed and high speed drives in many industrial applications, due to many advantages like the simplicity of construction, robustness, and low cost. The most common applications in recent years are related to aeronautics, electric and hybrid vehicles and wind power generation. This paper explores the theory, operation, design procedures and analysis of a variable reluctance machine. An iterative design methodology is introduced and used to design a 1.25 kW prototype. For the analysis of the machine two methods are used, an analytical method and the finite element simulation. The results obtained by both methods are compared. The results of finite element simulation are used to determine the inductance profiles and torque of the prototype. The magnetic saturation is examined visually and numerically in four critical points of the machine. The data collected in the simulation allow the verification of design and operating limits for the prototype. Moreover, the behavior of the output quantities is analyzed (inductance, torque and magnetic saturation) by variation of physical dimensions of the motor. Finally, a multiobjective optimization using Differential Evolution algorithms and Genetic Algorithms for switched reluctance machine design is proposed. The optimized variables are rotor and stator polar arcs, and the goals are to maximize the average torque, the average torque per copper losses and the average torque per core volume. Finally, the initial design and optimized design are compared.