11-12 of 12 results

  • Navigation and Control for Autonomous Vessels

    PI Darris White

    PI Eric Coyle

    PI Patrick Currier

    Development of closed-form solution for control of over-actuated maritime systems.

    A method for controlling the position, orientation and velocity of a marine vessel in a body of water with multiple, independently steered propulsion devices. The method involves receiving a command to move to a specific position and orientation. Utilizing position/heading feedback control, a control algorithm is used to calculate the required forces and moments to move the vehicle. Steering angles and thrust forces are determined for each of the vessel's propulsion devices. The thrust and angular displacement limits of each device are used to determine if the required forces and moments are achievable using one of three modes of operation: parallel steer, counter steer and combined parallel/counter steer. The approach fully utilizes the solution workspace for the over-actuated system without requiring the use of an optimization. The approach is used for smooth autonomous navigation in scenarios that include station keeping, path following, transitional states, disturbance rejection and object avoidance.

    Categories: Faculty-Staff

  • UAS Ground Collision Severity Evaluation

    PI Feng Zhu

    CO-I Eduardo Divo

    CO-I Victor Huayamave

    Increased use of UAS requires an in-depth understanding of the hazard severity and likelihood of UAS operations in the NAS. Due to their distinct characteristics (e.g. size, weight and shape) with manned aircraft systems, UAS operations may pose unique hazards to other aircraft and people on the ground. 

    Up to date, the studies on the UAS ground collision are still very much limited, particularly the scenario of impact between UAS and human body on the ground. Therefore, it is necessary to determine lethality thresholds for UAS using characteristic factors that affect the potential lethality of UAS in collisions with other objects, particularly human body on the ground. The objectives of this study are (1) to analyze the response and failure behavior of several typical UASs impact with human body on the ground; and (2) establish the damage threshold of UAS and its correlation with the key parameters in the crash accidents (e.g. shape, size and materials of UAS; impact energy and impulse etc.). To achieve this goal, advanced computational modeling techniques (e.g. finite element method/FEM) will be used to simulate the typical UAS/people impact scenarios.Based on the results, a design guidance can be further suggested to improve the crashworthiness of UAS and safety of personnel on the ground.

    Conventional 14 CFR system safety analyses include hazards to flight crew and occupants may not be applicable to unmanned aircraft.  It is necessary to determine the dedicated hazard severity thresholds for UAS and identify the key factors that affect the potential severity of UAS in collisions with other aircraft on the ground or in airborne encounters as well as collisions with people on the ground.  These severity thresholds will help determine acceptable corresponding system failure levels in accordance with the applicable 14 CFR requirements (for example 14 CFR 23.1309 and 14 CFR 25.1309).

    Categories: Faculty-Staff

11-12 of 12 results