Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. / Source: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 6944. Adviser: Steven M. LaValle. Includes bibliographical references (leaves 98-109) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. / Source: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 6956. Adviser: Lei F. Tian. Includes bibliographical references (leaves 119-127) Available on microfilm from Pro Quest Information and Learning.

<p> Over the years, researchers have been able to prove Brain Computer Interface (BCI) -P300 Speller as an effective communication tool. The first P300 speller was developed by Farwell and Donchin (1988), using the oddball paradigm to evoke a P300 response from a speller matrix. This P300 speller matrix has been a strong basis for studies that aimed at using BCI-P300 protocol for spelling, cursor movement, internet navigation or even control and manipulation of devices. However, application of P300 based BCI to controlling and manipulation of devices often involves the user relating with multiple interfaces. These multiple interfaces could be a distraction or have negative effects on the user (Fazel-Rezai <i>et al.</i> 2012) and as a consequence hinders the evoking of P300 potential and causing inaccurate classification. For this research, a novel P300 control matrix is developed by replacing the alphabets in the traditional P300 speller matrix with arrow images. Then the novel P300 control matrix was investigated to compare the P300 latency and amplitude to that of the traditional P300 speller matrix. The elements in the novel P300 control matrix were in form of arrows facing upward, left, right and downward directions, while elements in the P300 speller matrix were alphabets U, L, R and D for the upward, left, right and downward directions respectively. The participants were presented with a set of randomly sequenced directions, and each participant decides which of the arrows or letters to focus on based on the direction presented to them. Electroencephalography (EEG) was used to record the brainwaves using the international 10-20 system of electrode placement. This research is potentially a more efficient approach for controlling devices using P300-based BCI systems by eradicating the need for multiple interfaces associated with BCI-robotic control systems that are based on P300 speller.</p><p>

<p> My thesis covers the design and fabrication of novel humanoid robotic eyes and the process of interfacing them with the industry robot, Baxter. The mechanism can reach a maximum saccade velocity comparable to that of human eyes. Unlike current robotic eye designs, these eyes have independent left-right and up-down gaze movements achieved using a servo and DC motor, respectively. A potentiometer and rotary encoder enable closed-loop control. An Arduino board and motor driver control the assembly. The motor requires a 12V power source, and all other components are powered through the Arduino from a PC. </p><p> Hand-eye coordination research influenced how the eyes were programmed to move relative to Baxter&rsquo;s grippers. Different modes were coded to adjust eye movement based on the durability of what Baxter is handling. Tests were performed on a component level as well as on the full assembly to prove functionality.</p><p>

<p> This thesis describes the design, development, and evaluation of a novel "self-sealing" suction technology for grasping. As humans desire robots capable of handling an increasingly diverse set of tasks, end effectors that are able to grasp the widest possible range of object shapes and sizes will be needed to achieve the desired versatility. Technologies enabling the exertion of local pulling contact forces (e.g. suction) can be extraordinarily useful toward this end by handling objects that do not have features smaller than the grasper, a challenge for traditional grippers. However, simple operation and cost effectiveness are also highly desirable. </p><p> To achieve these goals, we have developed a self-sealing suction technology for grasping. A small valve inside each suction cup nominally seals the suction port to maintain a vacuum within the system. Through the reaction forces of object contact, a lever action passively lifts the valve to engage suction on the object. Any cups not contacting the object remain sealed. In this way, a system with a large number of cups may effectively operate using any subset of its cups, even just one, to grasp an object. All cups may be connected to a central vacuum source without the need for local sensors or powered actuators for operation, forming a simple, compact, cost effective system. </p><p> This thesis begins with the detailed design and analysis of the self-sealing suction technology. An extensive evaluation of the technology's robustness and performance demonstrates its features and limits. This includes self-seal quality and leakage, object seal and reseal, cycle performance, and normal and shear force-displacement, among other characterizations. It then describes the development of several devices utilizing the technology. The potential impact of the technology is highlighted through applications of human-controlled, robotic, and aerial grasping and perching. Finally, mathematical tools are developed to analyze potential grasps developed using the technology. </p><p>

Nowadays, the application of robots covers almost all aspects of our daily life. They are used to perform increasing complex and critical operations. The increased critical applications have led to various reliability and safety problems, especially many people are injured and killed every year. This study presents reliability and availability analyses of six different standby robot-safety systems: one robot and (n-1) standby safety units with a perfect switch, one robot and (n-1) standby safety units with an imperfect switch, (n-1) standby robots and one safety unit with a perfect switch, (n-1) standby robots and one safety unit with an imperfect switch, n parallel robots and (m-1) standby unit with a perfect switch, and two parallel robots and one standby unit with an imperfect switch. With the aid of Markov and supplementary variable methods, general expressions for system state probabilities, system availability, reliability and mean time to failure were obtained. Plots of some of these expressions are shown to demonstrate the effect of varying failure rates or repair rates of the safety unit, and other parameters.

<p> Monocular simultaneous localization and mapping (SLAM) is an important technique that enables very inexpensive environment mapping and pose estimation in small systems such as smart phones and unmanned aerial vehicles. However, the information generated by monocular SLAM is in an arbitrary and unobservable scale, leading to drift and making it difficult to use with other sources of odometry for control or navigation. To correct this, the odometry needs to be aligned with metric scale odometry from another device, or else scale must be recovered from known features in the environment. Typically known environmental features are not available, and for systems such as cellphones or unmanned aerial vehicles (UAV), which may experience sustained, small scale, irregular motion, an IMU is often the only practical option. Because accelerometers measure acceleration and gravity, an inertial measurement unit (IMU) must filter out gravity and track orientation with complex algorithms in order to provide a linear acceleration measurement that can be used to recover SLAM scale. In this thesis, an alternative method will be proposed, which detects and removes gravity from the accelerometer measurement by using the unscaled direction of acceleration derived from the SLAM odometry.</p><p>

Origami can turn a sheet of paper into complex three-dimensional shapes, and similar folding techniques can be used to build structures and mechanisms. However, folding by hand can be difficult and time consuming. This has led to the development of self-folding materials that transform themselves from flat sheets into 3D shapes by bending themselves along hinges. A variety of self-folding methods have been demonstrated at a variety of length scales, but they have not yet been used to build complex machines. This dissertation demonstrates that self-folding can produce functional machines with a new laminate we refer to as a shape memory composite. We characterize the behavior of this composite with models and experimental data, and use this information to develop design rules for self-folding. We apply these rules to create devices at multiple length scales, including a model crane, a crawling robot, a lamp, and a model ship. / Engineering and Applied Sciences - Engineering Sciences

Flying insects exhibit a remarkable ability to fly in environments that are small, cluttered and highly dynamic. Inspired by these animals, scientist have made great strides in understanding the aerodynamic mechanisms behind insect-scale flapping-wing flight. By applying these mechanisms together with recent advances in meso-scale fabrication techniques, engineers built an insect-scale flapping-wing robot and demonstrated hover by actively controlling the robot about its roll and pitch axes. The robot, however, lacked control over its yaw axis preventing control over its heading angle. In this thesis, we show that the roll and pitch axes of a single actuator insect-scale flapping-wing robot can also be passively stabilized by the addition of a pair of aerodynamic dampers. We develop design guidelines for these dampers, showing that the previously unstable robot with the addition of the dampers is able to perform stable vertical flights and altitude control. To address the lack of yaw control, we develop a yaw torque generating mechanism inspired by the fruit fly wing hinge. We present the development of this mechanism in three stages: from the conceptual stage, to the torque measurement stage and finally to a hover capable stage. We show that the robot is able to generate sufficient yaw torque enabling the robot to transition from hover to heading control maneuvers. / Engineering and Applied Sciences - Engineering Sciences

A recurrent problem in mobile robotics is the difficulty to accurately estimate a robot's localization. The ability to successfully estimate the localization of a mobile robot is highly dependent on the type of sensory data used to infer its pose. Traditionally, this has been achieved with odometry and the integration of wheel encoders signals. A major drawback of this approach, however, is the inability to provide an accurate estimate of the heading orientation; a significant cause of odometry drift leading to navigation failure. Accordingly, there is a need for improved localization methods, and vision-based estimation holds promise for this purpose. This research proposes an alternative solution to pure odometry localization. To that end a visual pose estimation algorithm which combines robotic vision and odometry is proposed. The method utilizes scene image vanishing points for recovering the orientation of a mobile robot in a two-dimensional space. To assess the performance of the visual pose estimation algorithm on an operational prototype robotic vehicle developed in the course of the current research, an original pose tracking controller using the geometrical properties of Cardinal splines is implemented. The visual pose estimation algorithm is validated experimentally and compared against six sensory fusion schemes. The results show that the localization accuracy can be improved by one order of magnitude when compared to pure wheel encoder odometry. With regards to motion control, the pose tracking controller is also evaluated for the case of rectilinear trajectories. Future work on large-scale navigation strategies will be developed based on these ideas.