Currently available upper-limb prostheses do not meet the needs or aspirations of the amputee. Many technical challenges have been given as the limiting factors on the further development of these prostheses. Generally developments have occurred as incremental developments on three existing moderately successful archetypes; the cosmetic, body-powered and myoelectric prostheses. Continued development on these archetypes appears to be further separating prostheses into those primarily considered cosmetic and those primarily considered functional. However, amputees have a need both for function and cosmesis from their prostheses. Technology currently being developed for actuation and control in other laboratories indicates that the previous limitations placed on prosthesis design may be challenged. Therefore, it is appropriate to look for new design archetypes. This thesis describes the development, implementation and evaluation of mechanical analogies of the skeletal components of the human hand and arm which have the potential to inform the design of a new generation of upper-limb prostheses integrating cosmesis and function in a single device. The research has been undertaken using a form of practice led design research methodology. This iterative methodology uses physical models for both evaluation and also as a means of encouraging end-user involvement in the design process. These evaluations are then used in subsequent cycles of research activity. The research has concentrated on developing mechanical analogies of the joints of the hand, wrist, forearm and elbow. The joints of the hand are shown to have a simple and similar structure. Therefore, a modular mechanical archetype has been elucidated that results in a hand configuration made from multiple similar modules positioned at different points throughout the hand. However, the wrist and forearm contain more complex joints which have been found to be unique to their anatomical position. The selection of appropriate prototyping techniques has been an integral part of the research. Problems have arisen in assessing the degree of analogy achieved because the intact joints of the human skeleton are covered by soft tissue that has not been part of the skeletal analogy implemented. Additionally, it is postulated that there are subtleties to human movement which are not reflected in standard anthropometric measures. Therefore, a two stage evaluation has been undertaken that assesses the quality of the analogy realised in the models. This consists of goniometric measures to quantify basic angular rotations whilst qualitative evaluations by professionals with a good anatomical knowledge have been used to assess the more subtle movements within the joints. The skeletal mechanical analogy developed through this research has been shown through evaluation to simulate the articulations of the human upper-limb. The model embodies design principles that appear to have short and long term significance to the field of prosthetics. The production of a tangible model has not only aided evaluation but has also stimulated research in other centres into ways of actuating and controlling a future upper-limb prosthesis. Additionally, the mechanical analogy may have applications in the field of telepresence robotics, aerospace and the entertainment industry.

In this report, a method for exploiting the redundancy of a hand-arm mechanical system for manipulation tasks is illustrated. The basic idea is to try to exploit the different intrinsic capabilities of the arm and hand subsystems. The Jacobian transpose technique is at the core of the method: different behaviors of the two subsystems are obtained by means of constraints in Null(J) generated by non-orthogonal projectors. Comments about the computation of the constraints are reported in the memo, as well as a description of some preliminary experiments on a robotic system at the A.I. Lab., M.I.T.

No description available.

Thesis (M.S.)--University of British Columbia, 2002. / Includes bibliographical references (leaves 90-97)

This thesis proposes a test method for evaluating the perceived vibration which occurs at the driver's hand in automotive steering wheel interface. The objective of the research was to develop frequency weightings for quantifying the human perception of steering wheel hand-arm vibration. Family of frequency weightings were developed from equal sensation curves obtained from the psychophysical laboratory experimental tests. The previous literature suggests that the only internationally standardised frequency weighting Wh is not accurate to predict human perception of steering wheel hand-arm vibration (Amman et. al, 2005) because Wh was developed originally for health effects, not for the human perception. In addition, most of the data in hand-arm vibration are based upon responses from male subjects (Neely and Burström, 2006) and previous studies based only on sinusoidal stimuli. Further, it has been continuously suggested by researchers (Gnanasekarna et al., 2006; Morioka and Griffin, 2006; Ajovalasit and Giacomin, 2009) that only one weighting is not optimal to estimate the human perception at all vibrational magnitudes. In order to address these problems, the investigation of the effect of gender, body mass and the signal type on the equal sensation curves has been performed by means of psychophysical laboratory experimental tests. The test participants were seated on a steering wheel simulator which consists of a rigid frame, a rigid steering wheel, an automobile seat, an electrodynamic shaker unit, a power amplifier and a signal generator. The category-ratio Borg CR10 scale procedure was used to quantify the perceived vibration intensity. A same test protocol was used for each test and for each test subject. The first experiment was conducted to investigate the effect of gender using sinusoidal vibration with 40 test participants (20 males and 20 females). The results suggested that the male participants provided generally lower subjective ratings than the female participants. The second experiment was conducted using band-limited random vibration to investigate the effect of signal type between sinusoidal and band-limited random vibration with 30 test participants (15 males and 15 females). The results suggested that the equal sensation curves obtained using random vibration were generally steeper and deeper in the shape of the curves than those obtained using sinusoidal vibration. These differences may be due to the characteristics of random vibration which produce generally higher crest factors than sinusoidal vibration. The third experiment was conducted to investigate the effect of physical body mass with 40 test participants (20 light and 20 heavy participants) using sinusoidal vibration. The results suggested that the light participants produced generally higher subjective ratings than the heavy participants. From the results it can be suggested that the equal sensation curves for steering wheel rotational vibration differ mainly due to differences of body size rather than differences of gender. The final experiments was conducted using real road signals to quantify the human subjective response to representative driving condition and to use the results to define the selection method for choosing the adequate frequency weightings for the road signals by means of correlation analysis. The final experiment was performed with 40 test participants (20 light and 20 heavy participants) using 21 real road signals obtained from the road tests. From the results the hypothesis was established that different amplitude groups may require different frequency weightings. Three amplitude groups were defined and the frequency weightings were selected for each amplitude group. The following findings can be drawn from the research: • the equal sensation curves suggest a nonlinear dependency on both the frequency and the amplitude. • the subjective responses obtained from band-limited random stimuli were steeper and the deeper in the shape of the equal sensation curves than those obtained using sinusoidal vibration stimuli. • females provided higher perceived intensity values than the males for the same physical stimulus at most frequencies. • light test participants provided higher perceived intensity than the heavy test participants for the same physical stimulus at most frequencies. • the equal sensation curves for steering wheel rotational vibration differ mainly due to differences in body size, rather than differences of gender. • at least three frequency weightings may be necessary to estimate the subjective intensity for road surface stimuli.

<p>Hand-arm vibrationssyndrom (HAVS) är ett tillstånd som inte är så välkänt trots att det är ett relativt vanligt tillstånd bland flera yrkesgrupper. Ökad kunskap inom området kan vara ett redskap för arbetsterapeuter i mötet med patienter med HAVS. Syfte: Syftet var att beskriva den vetenskapliga dokumentationen om hand-arm vibration syndrome (HAVS). Metod: En systematisk litteraturstudie gjordes med sökningar i databaserna AMED, Cinahl och Medline. Nio artiklar valdes till resultatet. Resultat: Beskrivning av vilka bedömningsinstrument som används för bedömning av HAVS, samt vilka konsekvenser HAVS har på aktivitetsförmågan. I en av studierna genomfördes en behandlingsmetod. Flera av artiklarna beskriver svårigheter med ADL. Diskussion: Eftersom HAVS är svårt att diagnostisera och kan yttra sig på så många olika sätt, samt att det inte alltid ger tydliga symtom krävs många olika typer av instrument för att bedöma HAVS. Då gripförmågan ofta blir påverkad yttrar sig detta genom svårigheter att utföra ADL-aktiviteter. Det finns inte några effektiva behandlingsmetoder för personer med HAVS. Slutsats: En arbetsterapeut är viktig för denna grupp, eftersom arbetsterapeuten kan hjälpa till med förebyggande arbete bland annat genom ergonomiska råd. Även efter att skadan uppkommit kan en arbetsterapeut hitta strategier för att underlätta dagliga aktiviteter för personer med HAVS.</p>

Hand-arm vibrationssyndrom (HAVS) är ett tillstånd som inte är så välkänt trots att det är ett relativt vanligt tillstånd bland flera yrkesgrupper. Ökad kunskap inom området kan vara ett redskap för arbetsterapeuter i mötet med patienter med HAVS. Syfte: Syftet var att beskriva den vetenskapliga dokumentationen om hand-arm vibration syndrome (HAVS). Metod: En systematisk litteraturstudie gjordes med sökningar i databaserna AMED, Cinahl och Medline. Nio artiklar valdes till resultatet. Resultat: Beskrivning av vilka bedömningsinstrument som används för bedömning av HAVS, samt vilka konsekvenser HAVS har på aktivitetsförmågan. I en av studierna genomfördes en behandlingsmetod. Flera av artiklarna beskriver svårigheter med ADL. Diskussion: Eftersom HAVS är svårt att diagnostisera och kan yttra sig på så många olika sätt, samt att det inte alltid ger tydliga symtom krävs många olika typer av instrument för att bedöma HAVS. Då gripförmågan ofta blir påverkad yttrar sig detta genom svårigheter att utföra ADL-aktiviteter. Det finns inte några effektiva behandlingsmetoder för personer med HAVS. Slutsats: En arbetsterapeut är viktig för denna grupp, eftersom arbetsterapeuten kan hjälpa till med förebyggande arbete bland annat genom ergonomiska råd. Även efter att skadan uppkommit kan en arbetsterapeut hitta strategier för att underlätta dagliga aktiviteter för personer med HAVS.

No description available.

No description available.

No description available.