Auto Access

Project undertaken in course year 2022-23 with Volkswagen

Project Goal

Develop a system to deliver persons utilizing manual wheelchairs safely into and out of an autonomous commercial transportation vehicle and secures the person and their wheelchair into the vehicle as necessary for riding said vehicle without additional intervention from a human operator.

Project Motivation

There are currently 2.7 million manual wheelchair users in the United States, and current solutions for wheelchair securement in commercial vehicles require driver assistance.  However, as autonomous vehicle technology emerges, there may be no driver to assist passengers with securement. As autonomous vehicle technology emerges, assistance-free and wheelchair-accessible ingress, egress, and securement for these vehicles must be considered.


Autonomous level 5 technology is expected to take off as soon as 2030 according to field experts. Since no human assistance will be available with these vehicles, ingress/egress and securement systems for users of mechanical wheelchairs must be integrated.  Volkswagen is currently developing its own level 5 autonomous vehcile, the Sedric, which will allow manual wheelchair users to seamlessly and safely get to their destination in the future. 

Volkswagen's Sedric Autonomous level 5 concept car
Current wheelchair lift solution, requiring another person to operate the lift

High Priority Requirements

Ethical Considerations


We developed a solution for entry, exit and securement of a manual wheelchair user in a vehicle without assistance from a driver.  Our solution consists of a four-bar actuated ramp for entry and exit, and a spring-loaded mechanism that attaches to the frame of the wheelchair for securement. 

4-bar ramp mechanism

Stowed and deployed view of the ramp mechanism. The included drawer slides grant the ramp low-profile storage with versatile motion.


System used for securement of wheelchair in to vehicle.  The cutaway shows the mechanism itself, and the upper image shows the wheelchair secured by the system as it grip onto the frame

CAD image of 4-bar

CAD rendering of one side of hte ramp mechanism. The arms have been spaced in such a way to avoid intersections during motion while remaining highly concealable. 

CAD image of securement tooth

Internal mechanism of the securement. A simple compression spring pushes the tooth outward, and the backstop and casing prevent the wheelchair movements both backwards and horizontally. 

Tooth FEA

Stress analysis of lateral load case using PLA material property data. 

Ramp friction testing

Coefficient of friction test setup, showing the wet ramp surface, wheelchair, and phone used for angle measurement

Ramp deflection testing

Measuring the deflection of the ramp under measured load.  A calipers are used as a depth gage.

Ramp deflection FEA

Analysis of a subsection of the initial ramp design, showing max stress at the center. These resulted in a deflection under 1.5mm, meeting requirements.

Ramp deflecton vs applied force

The ramp deflected a maximum of 1.3mm with 900 lb load, below the desired 1.5mm, meeting requirements.  Results also agreed well with predicted, showing an R-sq of 0.923

User trials time to secure

8 first-time users performed the securement process, moving the wheelchair up the ramp and into the securement.  All users were below 40s threshold.

Other testing conducted

Student team

Future Work