In order for a mobile robot to complete its task it must be able to plan and follow a trajectory. Depending on the environment, it may also be necessary to follow a given velocity profile. This is known as temporal planning. Temporal planning can be used to minimize time of motion and to avoid moving obstacles. For example, assuming the mobile robot is an intelligent wheelchair, it must follow a prescribed path (sidewalk, hospital corridor) while following a strict speed limit (slowing down for pedestrians, cars). Computing a realistic velocity profile for a mobile robot is a challenging task due to a large number of kinematic and dynamic constraints that are involved. Unlike prior works which performed temporal planning in a 2-dimensional environment, this thesis presents a new temporal planning algorithm in a 3-dimensional environment. This algorithm is implemented on a wheeled mobile robot that is to be used in a healthcare setting. The path planning stage is accomplished by using cubic spline functions. A rudimentary trajectory is created by assigning an arbitrary time to each segment of the path. This trajectory is made feasible by applying a number of constraints and using a linear scaling technique. When a velocity profile is provided, a non-linear time scaling technique is used to fit the robots center linear velocity to the specified velocity. A method for avoiding moving obstacles is also implemented. Both simulation and experimental results for the wheeled mobile robot are presented. These results show good agreement with each other. For both simulation and experimentation, six different examples of paths in the Engineering Building of the University of Saskatchewan, were used. Experiments were performed using the PowerBot mobile robot in the robotics lab at the University of Saskatchewan.

Background: Currently, if traveling the posted speed limit, the typical commuter driver in the Toronto Metropolitan area will travel round trip upwards of 60 minutes a day to work (Heisz and LaRochelle-Cote, 2005). As urban congestion continues to rise, commuting distances and times will progressively increase, placing commuter drivers at increased risk of developing musculoskeletal disorders (Porter and Gyi, 2002; Walsh et al., 1989; Chen et al., 2005; Sakakibara et al., 2006). As urban areas continue to expand, it is believed that a greater percentage of our urban populations will be defined as overweight or obese (Puska et al., 2003). To date the influence of body mass on driver posture, pressure distribution and discomfort during a prolonged driving situation has been left relatively untested. The purpose of this investigation is to determine the influence body mass has on driver posture, pressure distribution and discomfort during a prolonged driving situation. Methodology: Twelve male and 12 female participants, between 167 and 172 cm in stature were used in this investigation. Even numbers of males were assigned to either a light (51.3-57.7 kg), moderate (63.7-69.4 kg), or heavy (82.7-92.0 kg) body mass group. Participants were than placed in a 2 hour in lab driving simulation. During the simulation, lumbar flexion, pelvic angle, joint/segment angles, pressure distribution and discomfort were recorded. A three way mixed general linear model was used to determine if significant (α = 0.05) differences in discomfort, posture and/or interface pressure measurements existed over time. Results: Heavy drivers displayed increased total IT pressures and total seat pan/back pressures during driving. When normalizing these total pressures to area, differences in total IT pressure recorded from the seat pan, and total pressure recorded from the seat back were not significantly different (α = 0.05) across body mass groups. Due to the lack of seat pan accommodation with respect to surface area, the heavy body mass group’s total pressures per unit area for the seat pan was elevated relative to the lighter body mass groups. No differences in two-dimensional joint or segment kinematics and ratings of perceived discomfort were observed between body mass groups or between genders. Gender specific lumbo-pelvic postures and pressure distribution profiles were observed. Conclusion: With appropriate design of the seat pan to accommodate heavy body mass populations with respect to seat pan area, the influence of body mass as a potential risk factor in the development of discomfort would be reduced. With stature and body mass controlled between gender groups, biomechanical differences in both pressure distribution and lumbo-sacral postures were observed between males and females, verifying gender as a risk factor in the development of discomfort during prolonged driving. Recommendations to car seat manufacturers to recognize gender and body mass as important variables in the design of a car seat should be made.

Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight. However, except for a few special cases, the specific inclinations of individual AGN are unknown. We have developed a promising technique for determining the inclinations of nearby AGN by mapping the kinematics of their narrow-line regions (NLRs), which are easily resolved with Hubble Space Telescope (HST) [O III] imaging and long-slit spectra from the Space Telescope Imaging Spectrograph (STIS). Our studies indicate that NLR kinematics dominated by radial outflow can be fit with simple biconical outflow models that can be used to determine the inclination of the bicone axis, and hence the obscuring torus, with respect to our line of sight. We present NLR analysis of 52 Seyfert galaxies and resultant inclinations from models of 17 individual AGN with clear signatures of biconical outflow. From these AGN, we can for the first time assess the effect of inclination on other observable properties in radio-quiet AGN, including the discovery of a distinct correlation between AGN inclination and X-ray column density.

Background: Currently, if traveling the posted speed limit, the typical commuter driver in the Toronto Metropolitan area will travel round trip upwards of 60 minutes a day to work (Heisz and LaRochelle-Cote, 2005). As urban congestion continues to rise, commuting distances and times will progressively increase, placing commuter drivers at increased risk of developing musculoskeletal disorders (Porter and Gyi, 2002; Walsh et al., 1989; Chen et al., 2005; Sakakibara et al., 2006). As urban areas continue to expand, it is believed that a greater percentage of our urban populations will be defined as overweight or obese (Puska et al., 2003). To date the influence of body mass on driver posture, pressure distribution and discomfort during a prolonged driving situation has been left relatively untested. The purpose of this investigation is to determine the influence body mass has on driver posture, pressure distribution and discomfort during a prolonged driving situation. Methodology: Twelve male and 12 female participants, between 167 and 172 cm in stature were used in this investigation. Even numbers of males were assigned to either a light (51.3-57.7 kg), moderate (63.7-69.4 kg), or heavy (82.7-92.0 kg) body mass group. Participants were than placed in a 2 hour in lab driving simulation. During the simulation, lumbar flexion, pelvic angle, joint/segment angles, pressure distribution and discomfort were recorded. A three way mixed general linear model was used to determine if significant (α = 0.05) differences in discomfort, posture and/or interface pressure measurements existed over time. Results: Heavy drivers displayed increased total IT pressures and total seat pan/back pressures during driving. When normalizing these total pressures to area, differences in total IT pressure recorded from the seat pan, and total pressure recorded from the seat back were not significantly different (α = 0.05) across body mass groups. Due to the lack of seat pan accommodation with respect to surface area, the heavy body mass group’s total pressures per unit area for the seat pan was elevated relative to the lighter body mass groups. No differences in two-dimensional joint or segment kinematics and ratings of perceived discomfort were observed between body mass groups or between genders. Gender specific lumbo-pelvic postures and pressure distribution profiles were observed. Conclusion: With appropriate design of the seat pan to accommodate heavy body mass populations with respect to seat pan area, the influence of body mass as a potential risk factor in the development of discomfort would be reduced. With stature and body mass controlled between gender groups, biomechanical differences in both pressure distribution and lumbo-sacral postures were observed between males and females, verifying gender as a risk factor in the development of discomfort during prolonged driving. Recommendations to car seat manufacturers to recognize gender and body mass as important variables in the design of a car seat should be made.

Although several studies have investigated the effects of aging on aspects of motor planning and control, there remains a lack of consensus about the underlying mechanisms responsible for the motor slowing associated with aging. This may, at least partially, be due to the fact that few studies have kinematically examined both the transport and grasp components in both younger and older adults, and furthermore, even fewer have examined these movements when the context of the task is changed, such as when the movement is performed in isolation compared to when it is embedded in a sequence. Therefore, the purpose of this thesis was threefold: 1) to investigate how aging affects performance on a single reach-to-grasp movement, 2) to examine how movement context affects performance on the reach-to-grasp movement when it is performed alone or as the first movement in a two-movement sequence- in other words, are older adults able to plan the first motor task movement in anticipation of performing a subsequent task, and 3) whether younger and older adults are able to plan, execute, and modify that movement in accordance with the extrinsic properties of the subsequent movement task (near versus far target for second movement). To address this, the movement profiles of both younger (N=14; mean age= 20.7 years; 4 males, 10 females) and older (N=11; mean age= 75.1 years; 3 males, 8 females) healthy right-handed adults were compared on performing a reach-to-grasp movement under 3 different movement conditions: single-movement task, two-movement sequence to near target, and two-movement sequence to far target. For the two-movement sequence conditions, participants were instructed to reach and grasp the object (like the single-movement task), but then to move and place it on either a closer (near condition) or farther (far condition) target location. Overall, the results from this study are in agreement with the literature showing older adults to have slower movements in general and consistently taking longer to both initiate and execute the reach-to-grasp movement than the younger adults for all conditions. There were no other differences between groups on the single-movement condition. For all participants, the reach-to-grasp movement took longer when it was performed in isolation than when it was embedded as the first part of a two-movement sequence. This finding can be explained by the movement termination effect and is consistent with findings from studies on aiming movements showing that when the movement plan involves stabilizing the arm at the first target (single-movement) as opposed to merely slowing it down (two-movement sequence tasks), the constraint of achieving a stabile position imposes a greater demand, thus requiring the movement iv to be made more slowly. The results obtained from the study indicate that the movement termination effect is also seen in the context of prehensile movements and furthermore, this effect on performance persists with age. Not only do the findings from this study show that this effect persists with age, but also that this effect increases with age, as revealed by a Group by Condition effect for reaction time, movement time, and relative timing of the velocity profile, indicating greater changes in reaching performance between single- and two-movement conditions for the older adults than for the younger adults. Upon further examination of the details of the movement, it is apparent this movement termination effect is reflected in the ballistic phase of the movement. This last notion is inconsistent with previous studies, which showed the increased movement time associated with the movement termination effect was the result of changes in the amount of time spent in the deceleration phase toward the end of the movement rather than the beginning of the movement. Lastly, when reach-to-grasp performance was compared between moving to a near- compared to a far-target in the two-movement conditions, no differences were found between any of the movement features for either group. This suggests that the increased proportion of time spent in deceleration for the dual-movement conditions compared to the single-movement condition in older adults is due to online feedback control for terminating the first movement rather than online planning of the second movement. Despite the changes seen in the transport component, the findings for the manipulation component indicate that the formation of the grasp and its relative coupling with the transport component remains intact with age.

In order for a mobile robot to complete its task it must be able to plan and follow a trajectory. Depending on the environment, it may also be necessary to follow a given velocity profile. This is known as temporal planning. Temporal planning can be used to minimize time of motion and to avoid moving obstacles. For example, assuming the mobile robot is an intelligent wheelchair, it must follow a prescribed path (sidewalk, hospital corridor) while following a strict speed limit (slowing down for pedestrians, cars). Computing a realistic velocity profile for a mobile robot is a challenging task due to a large number of kinematic and dynamic constraints that are involved. Unlike prior works which performed temporal planning in a 2-dimensional environment, this thesis presents a new temporal planning algorithm in a 3-dimensional environment. This algorithm is implemented on a wheeled mobile robot that is to be used in a healthcare setting. The path planning stage is accomplished by using cubic spline functions. A rudimentary trajectory is created by assigning an arbitrary time to each segment of the path. This trajectory is made feasible by applying a number of constraints and using a linear scaling technique. When a velocity profile is provided, a non-linear time scaling technique is used to fit the robots center linear velocity to the specified velocity. A method for avoiding moving obstacles is also implemented. Both simulation and experimental results for the wheeled mobile robot are presented. These results show good agreement with each other. For both simulation and experimentation, six different examples of paths in the Engineering Building of the University of Saskatchewan, were used. Experiments were performed using the PowerBot mobile robot in the robotics lab at the University of Saskatchewan.

It is well documented that the mechanical response of polycrystalline metals depends on the metal's microstructure, for example the dependence of yield strength on grain size (Hall-Petch effect). Local continuum approaches do not address the sensitivity of deformation to microstructural features, and are therefore unable to capture much of the experimentally observed behavior of polycrystal deformation. In this work, a crystal plasticity model is developed that predicts a dependence of yield strength on grain size without grain size explicitly entering into the constitutive equations. The grain size dependence in the model is the result of non-local effects of geometrically necessary dislocations (GNDs), i.e. GNDs harden both the material at a point and the surrounding material. The conventional FeFp kinematics for single crystals have been augmented based on a geometric argument that accounts for the grain orientations in a polycrystal. The augmented kinematics allows an initial GND state at grain boundaries and an evolving GND state due to sub-grain formation within the grain to be determined in a consistent manner. Numerically, these non-local affects are captured using a non-local integral approach rather than a conventional gradient approach. The non-local crystal plasticity model is used to simulate the tensile behavior in copper polycrystals with grain sizes ranging from 14 to 244 micron. The simulation results show a grain size dependence on the polycrystal's yield strength, which are qualitatively in good agreement with the experimental data. However, the Hall-Petch exponent predicted by the simulations is more like d-1 rather than d-0.5. The effects of different simulation parameters including grain shape and misorientation distribution did not greatly affect the Hall-Petch exponent. The simulation results indicate that the Hall-Petch exponent is sensitive to the grain boundary strength: the Hall-Petch exponent decreases as grain boundary strength decreases. The intragrain misorientations predicted by the non-local model were compared with experiments on polycrystalline nickel. Experimentally, the intragrain misorientations were tracked by electron back scatter diffraction (EBSD) at various strain levels from the same location. On average, the simulation results predicted enough misorientation throughout the sample. However, the model did not correctly predict the spatial details of the intragrain misorientation.

The main objective of this study was to determine differences, if any, in three-dimensional (3D) kinematic characteristics of the three principal punches (the jab, hook and uppercut) executed by novice, intermediate and elite level amateur boxers. Specifically, the kinematic variables related to the displacement, linear velocity and acceleration of the upper body segments, translational hand acceleration and vertical ground reaction force generated by boxers were analyzed. The subjects of this study composed of 10 novice, 9 intermediate, and 11 elite level amateur boxers. Ages of the subjects ranged from 18 to 34 years old. All subjects executed their punches toward a head-high target on a standard practice bag. The motions were captured with PhaseSpace real time optical tracking system with 8 high speed cameras at 240 fps. Then, the motions captured were analyzed to quantify the kinematic factors associated with each punch. The results showed that the uppercut punch generated larger linear shoulder, elbow and wrist velocity compared to the jab punch. Similarly, the uppercut punch generated larger linear shoulder, elbow and wrist acceleration compared to the hook and jab punches. Moreover, the uppercut and hook punches generated larger translational hand acceleration compared to the jab punch. As a conclusion, the results for all kinematic variables demonstrated that the type of punch executed was the major determinant of the magnitude of each factor studied. Moreover, the technique employed can significantly affect the resulting displacement, linear velocity and acceleration, and translational hand acceleration of the fist.

The skill of putting in golf contributes approximately 40 percent to one’s total score making it an important skill to master in golf. One of the critical means of improving putting skill is through practice. The purpose of this study was to: (a) investigate if different practice schedules with different degrees of contextual interference (CI) influenced the participants’ immediate and long-term putting performance, (b) examine if performance changes were associated with concomitant changes in specific kinematic parameters, and (c) assess the cognitions of the participants during various stages of the practice of the putting skill. Twenty-four undergraduate students were randomly assigned to either a blocked or random practice schedule. On Day One each participant practiced putting to three targets (4 ft, 8 ft, and 12 ft distance) for a total of 108 trials (36 trials to each target). On Day Two 30 trials of retention (10 trials to each target) and 10 transfer trials (10 ft distance) were performed. To obtain a kinematic description of the putting action, an OPTOTRAKTM 3020 camera system recorded the 3D movement of the putter. Participants’ cognitions were analyzed from stimulated recall interview data. Random practice participants exhibited poorer putting performance during acquisition compared to their blocked practice counterparts but showed superior performance in retention and transfer tests. While the blocked practice participants had significantly lower variability in the amplitude in the x-dimension for backswing, impact velocity, and putter position at impact (z-dimension) during practice, the random practice participants showed significantly lower variability in the amplitude of the x-dimension for the backswing and downswing, impact velocity, and putter position at impact during the retention and transfer phases. Content analysis of interview data yielded three emergent categories: participant focus, self-evaluation of performance, and benefits of practice. The participants provided evidence of active thought processes during the putting task while receiving little instruction. The blocked group focused more on accuracy while the random group was more focused on judging distance. The lack of recognition about the z-dimension has potential implications for how instruction and feedback might be employed during the learning process.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains viii, 64 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 63-64).