Browsing by Author "Orpen, Kevin"

Now showing 1 - 4 of 4
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    Design and Modeling of Anchoring Segments of Burrowing Hydraulic Soft Robots
    (2019) Orpen, Kevin
    Many of today’s utilities, such as water, sewage, and telecommunication, use underground tunneling and excavation to install these services. Current methods of installation and repair, primarily trench excavation and directional boring, are costly and disruptive. No compact system exists that addresses the need for an efficient, high-force burrowing mechanism. This research into a soft robot burrowing solution seeks to prove the hypothesis that a power-dense, hydraulic system can be utilized to generate the high forces required in confined-space burrowing. The proposed design is a multi-segment robot that utilizes biomimicry and the peristaltic motion of an earthworm. Two ballooning segments will generate anchoring forces by radially compressing the surrounding soil substrate, balancing the force from an extending segment moving the robot’s head forward to form the burrow. This particular research focused on the design, modeling, and optimization of the traction segments of the robot. Various concepts for actuator geometry and manufacturing approaches were examined. Prototypes were tested to determine hydraulic operating pressures and to validate initial traction models in a rigid tube. Iterative actuator design framework and modeling of gait kinematics will be used to validate this type of robot for future applications, including utility installation and underwater anchoring.
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    Dynamic Modeling and Simulation of an Autonomous Underwater Vehicle (AUV)
    (2021) Orpen, Kevin;
    Autonomous Underwater Vehicles (AUVs) have been in development in recent decades to address the difficulties and high costs of oceanic exploration, with applications including marine life monitoring, search and rescue operations, and wreck inspection. An underwater robot developed by the Interactive Robotics and Vision (IRV) Laboratory at the University of Minnesota is LoCO, a Low Cost Open-Source AUV. LoCO seeks to assist in a number of underwater applications while reducing the current high cost of entry into underwater robotics. One aspect of this underwater vehicle that is integral to its capacity as an AUV is the modeling of its dynamics, and each new AUV comes with unique geometries spanning various propulsion control methods for specializing in different underwater tasks. This thesis seeks to establish an underwater dynamic model for the robot, implement the model in a simulated setting so as to provide testing opportunities before field deployment, and compare the effectivity of the model to collected experimental data. This, in turn, will lead to the efficient development of its autonomous systems and capability to assist in underwater operations. Within this research, the dynamic models have been produced and geometry-dependent coefficients have been derived for LoCO. A simulator for the robot has also been developed that can interface with onboard software. Though the simulation agrees relatively well with experimental data collected for LoCO’s forward motion, there are still other motion modes that require further investigation. Overall, this dynamic foundation will provide for future control system and other autonomous development to further its underwater capabilities.
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    Towards Dynamics Modeling for an Autonomous Underwater Vehicle (AUV) in Experimental and Simulated Settings
    (2020) Orpen, Kevin
    Autonomous Underwater Vehicles (AUVs) have been in development in recent decades to address the difficulties and high costs of oceanic exploration, with a myriad of applications including marine life monitoring and search and rescue operations. An underwater robot in development by the Interactive Robotics and Vision (IRV) Laboratory at the University of Minnesota is LoCO, a Low Cost Open-Source AUV aiming to reduce the current high cost of entry into underwater robotics. One aspect critical to its capacity as an AUV is its autopilot system, which enables stability augmentation and predictable control behavior. Each new AUV comes with unique characteristics, requiring distinctive autopilot designs. This research seeks to prove the hypothesis that the known properties common to underwater environments (e.g., buoyancy and drag forces) can be characterized alongside parameterized variables adaptable to various AUV configurations. This understanding will lead to the efficient development of autopilot systems based on both dynamics modeling and experimental data, opposed to the purely experimental approximation of control parameters. Focusing on LoCO, this particular research centered on the development of a simulation program in Gazebo utilizing Robot Operating System (ROS) that has the potential to reduce time and cost spent on physical testing. Various physics aspects for simulated locomotion were considered alongside the implementation of initial underwater forces. Experimental data from physical testing was collected to characterize LoCO’s forward motion to aid in this initial modeling. Further evaluation and validation of dynamics modeling will build upon this framework, assisting in future control system development.