Date of Award

4-2020

Degree Name

Master of Science in Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Dr. Zachary Asher

Second Advisor

Dr. Mitchel Keil

Third Advisor

Dr. Kapseong Ro

Keywords

Autonomous vehicles, accessibility, vehicle dynamics, vehicle performance, cost analysis

Access Setting

Masters Thesis-Open Access

Abstract

Autonomous vehicles (AV) have the potential to vastly improve independent, safe, and cost-effective mobility options for individuals with disabilities. However, accessibility considerations are often overlooked in the early stages of design, resulting in AVs that are inaccessible to people with disabilities. The needs of wheeled mobility device users can cause significant vehicle design changes due to requirements for stepless ingress/egress and increased space for onboard circulation and securement. Vehicles serving people with disabilities typically require costly aftermarket modifications for accessibility, which may have unforeseen impacts on vehicle performance and safety, particularly in the case of automated vehicles. In this research, we investigate the performance of three autonomous shuttle design configurations: an off the shelf shuttle that is not wheelchair accessible, the campus pilot shuttle that is wheelchair accessible, and a new design using wheelchair accessibility foresight. Physics-based simulations performed using MATLAB, ADAMS, and Autonomie demonstrated that the modifications aimed at providing wheelchair access had important implications for vehicle dynamics (e.g., turning radius, pitch, roll) and energy consumption (operating range and usage duration). A ride comfort analysis was performed using MATLAB to study the passenger's ride comfort in all three-shuttle designs. Also, energy consumption and lateral dynamic analyses were performed to analyze the operating range and turning radius of the shuttles. Since modern suspension systems are being integrated with an active control suspension system, an active control suspension model was developed in order to observe the benefits of incorporating this technology into our new design. In order to test the control system of the active suspension developed, a co-simulation was performed using ADAMS and MATLAB. Simulation results indicate that integrating this suspension system provides substantial benefits to ride comfort. The campus pilot shuttle design adversely affects the turning radius and reduces driving range by 38% while the new design makes no compromises in vehicle dynamics or driving range. We conclude that if wheelchair access and related accessibility considerations are incorporated in the design phase, the adverse performance of aftermarket modifications can be avoided.

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