DESIGN AND FABRICATION OF AN UNMANNED GROUND VEHICLE UTILIZING VARIABLE INTERNAL INERTIAL PROPERTIES

Mobility of an Unmanned Ground Vehicle (UGV) is highly dependent upon the maximum lateral and longitudinal forces that can be generated at the tire/ground interface. These forces are a function of a number of di erent vehicle properties such as suspension geometry, actuators and the tire/terrain interaction mechanics. Typically these properties are xed imposing general limits to the vehicle's maximum achievable lateral and longitudinal accelerations. If you were instead able to modify these parameters dynamically during vehicle operation substantial improvements in robot mobility can be realized. This thesis presents the design a fabrication of the Variable Inertial Vehicle (VIV) which is capable of realizing this. It uses a shifting mass mechanism to vary the normal load distribution among the front and rear tire based upon the desired operating conditions. The shifting mass mechanism is capable of moving a substantial amount of the vehicle along it longitudinally. This provides direction control of the tire normal forces during operation. Described in this thesis is the design of this unique element and its e ects on the rest of the vehicle design. The other main elements di erentiating the VIV from common UGV's such as the electronics, suspension, chassis, and powertrain are also detailed. Finally, a number of experiments utilizing the VIV are presented. These experiments were devised and performed my Chenghui Nie but are presented here to demonstrate the functionality and capabilities of the VIV.M.S. in Mechanical Engineering, December 201

Hybrid electrostatic and micro-structured adhesives for robotic applications

Current adhesives and gripping mechanisms used in many robotics applications function on very specific surface types or at defined attachment locations. A controllable, i.e. ON-OFF, adhesive mechanism that can operate on a wide range of surfaces would be very advantageous. Such a device would have applications ranging from robotic gripping and climbing to satellite docking and inspection/service missions. The main goal of the research presented here was to create such an attachment mechanism through the use of a new hybrid adhesive technology. The newly developed adhesive technology is a hybridization of electrostatic and micro-structured dry adhesion. The result provides enhanced robustness and utility, particularly on rough surfaces. There were challenges not only in the integration of these two adhesive elements but also with its application in a complete gripping mechanism. Electrostatic and directional dry adhesives were both individually investigated. The electrode geometry for an electrostatic adhesive was optimized for maximum adhesion force using finite element analysis software. Optimization results were then verified through experimental testing. New manufacturing techniques were also developed for electrostatic adhesives that utilized a metalized mesh embedded in a silicone polymer and Kapton film based construction, greatly improving adhesion. The micro-structured dry adhesive used was provided by Dr. Aaron Parness, from the NASA Jet Propulsion Lab (JPL), and consists of an array of vertical stalks with an angled front face, referred to as micro-wedges. The hybrid electrostatic dry adhesive (EDA) was created by fabricating the electrostatic adhesive directly on top of a dry adhesive mold. This process created an array of dry adhesive micro-wedges directly on the surface of the electrostatic adhesive. In operation the electrostatic adhesive provides a normal force which serves to pull the dry adhesive into the surface substrate. With greater surface contact more of the dry adhesive is able to engage, bring the electrostatic adhesive even closer to the surface and increasing its effectiveness. Therefore, the combination of these two technologies creates a positive feedback cycle whose whole is often greater than the sum of its parts. An interface mechanism is needed to transmit applied loads from a rigid structure to the flexible adhesive while still maintaining its conformability. This is especially important for strong adhesion on rough surfaces, such as tile and drywall. Different concepts such as a structured fibrillar hierarchy and a fluid-filled backing pouch have been explored. Additionally, finite element analysis was used to evaluate different fribrillar shapes and geometries for the structured hierarchy. The goal was to equalize the load distribution across the adhesive while still maintaining surface compliance. A gripper mechanism was also created which used a servo for actuation and three rigid tiles with a directional dry adhesive. It was tested on a perching Micro Air Vehicle (MAV) as well as in the RoboDome facility at NASA's Jet Propulsion lab to simulate a satellite docking/capture maneuver

HYBRID ELECTROSTATIC AND MICRO-STRUCTURED ADHESIVES FOR ROBOTIC APPLICATIONS

Current adhesives and gripping mechanisms used in many robotics applica- tions function on very speci c surface types or at de ned attachment locations. A controllable, i.e. ON-OFF, adhesive mechanism that can operate on a wide range of surfaces would be very advantageous. Such a device would have applications ranging from robotic gripping and climbing to satellite docking and inspection/service mis- sions. The main goal of the research presented here was to create such an attachment mechanism through the use of a new hybrid adhesive technology. The newly devel- oped adhesive technology is a hybridization of electrostatic and micro-structured dry adhesion. The result provides enhanced robustness and utility, particularly on rough surfaces. There were challenges not only in the integration of these two adhesive elements but also with its application in a complete gripping mechanism. Electrostatic and directional dry adhesives were both individually investigated. The electrode geometry for an electrostatic adhesive was optimized for maximum ad- hesion force using nite element analysis software. Optimization results were then veri ed through experimental testing. New manufacturing techniques were also de- veloped for electrostatic adhesives that utilized a metalized mesh embedded in a sili- cone polymer and Kapton lm based construction, greatly improving adhesion. The micro-structured dry adhesive used was provided by Dr. Parness, from the NASA Jet Propulsion Lab (JPL), and consists of an array of vertical stalks with an angled front face, referred to as micro-wedges. The hybrid electrostatic dry adhesive (EDA) was created by fabricating the electrostatic adhesive directly on top of a dry adhesive mold. This process created an array of dry adhesive micro-wedges directly on the surface of the electrostatic adhesive. In operation the electrostatic adhesive provides a normal force which serves to pull the dry adhesive into the surface substrate. With greater surface contact more of the dry adhesive is able to engage, bring the electro-static adhesive even closer to the surface and increasing its e ectiveness. Therefore, the combination of these two technologies creates a positive feedback cycle whose whole is often greater than the sum of its parts. An interface mechanism is needed to transmit applied loads from a rigid struc- ture to the exiable adhesive while still maintaining its conformability. This is es- pecially important for strong adhesion on rough surfaces, such as tile and drywall. Di erent concepts such as a structured brillar hierarchy and a uid- lled backing pouch have been explored. Additionally, nite element analysis was used to evaluate di erent fribrillar shapes and geometry for the structured hierarchy. The goal was to equalize the load distribution across the adhesive while still maintaining surface compliance. A gripper mechanism was also created which used a servo for actuation and three rigid tiles with a directional dry adhesive. It was tested on a perching Micro Air Vehicle (MAV) as well as in the RoboDome facility at NASA's Jet Propulsion lab to simulate a satellite docking/capture maneuver.Ph.D. in Mechanical and Aerospace Engineering, July 201

Arteriovenous fistula as a complication of lumbar disc surgery

The Fall 2008 semester of IPRO 303 will investigate and analyze the economic and technical details of the wind-turbine electricity generation industry. The IPRO 303 team will be focusing on the impact of equipment failures that lead to downtime and maintenance associated with the failures. A comparison of current industry practices in dealing with these problems, along with a detailed economic analysis of the true costs involved, will be the major goal. A final report of the findings and conclusions of the IPRO 303 team will be provided to our sponsor, SmartSignal Inc. It is understood that this Project Plan will change as the term progresses and more information becomes available.Sponsorship: SmartSignalDeliverable

Operational Considerations in Wind Power Generation (Semester Unknown) IPRO 303: Operational Considerations in Wind Power Generation IPRO 303 Project Plan F08

The Fall 2008 semester of IPRO 303 will investigate and analyze the economic and technical details of the wind-turbine electricity generation industry. The IPRO 303 team will be focusing on the impact of equipment failures that lead to downtime and maintenance associated with the failures. A comparison of current industry practices in dealing with these problems, along with a detailed economic analysis of the true costs involved, will be the major goal. A final report of the findings and conclusions of the IPRO 303 team will be provided to our sponsor, SmartSignal Inc. It is understood that this Project Plan will change as the term progresses and more information becomes available.Sponsorship: SmartSignalDeliverable

Operational Considerations in Wind Power Generation (Semester Unknown) IPRO 303

The Fall 2008 semester of IPRO 303 will investigate and analyze the economic and technical details of the wind-turbine electricity generation industry. The IPRO 303 team will be focusing on the impact of equipment failures that lead to downtime and maintenance associated with the failures. A comparison of current industry practices in dealing with these problems, along with a detailed economic analysis of the true costs involved, will be the major goal. A final report of the findings and conclusions of the IPRO 303 team will be provided to our sponsor, SmartSignal Inc. It is understood that this Project Plan will change as the term progresses and more information becomes available.Sponsorship: SmartSignalDeliverable

Operational Considerations in Wind Power Generation (Semester Unknown) IPRO 303: Operational Considerations in Wind Power Generation IPRO 303 Final Presentation F08

The Fall 2008 semester of IPRO 303 will investigate and analyze the economic and technical details of the wind-turbine electricity generation industry. The IPRO 303 team will be focusing on the impact of equipment failures that lead to downtime and maintenance associated with the failures. A comparison of current industry practices in dealing with these problems, along with a detailed economic analysis of the true costs involved, will be the major goal. A final report of the findings and conclusions of the IPRO 303 team will be provided to our sponsor, SmartSignal Inc. It is understood that this Project Plan will change as the term progresses and more information becomes available.Sponsorship: SmartSignalDeliverable