Creating a functional door prototype to accelerate client user studies
Motivo’s client is a multinational automotive OEM known for pushing the future of automotive technologies while highly considering human factors and consumer perception. The client’s Product Planning team wanted to combine the convenience of a minivan sliding door with a “cooler” form-factor. The client partnered with Motivo to create a functional proof of concept to support the client’s intensive user studies.
One of the challenges Motivo faced was the door mechanism needed to be retrofitted into an existing vehicle. Other requirements came to light while learning more about the end consumer’s preferences from the client. The motion needed to be easy to use while avoiding minivan stigma points such as door support rails cutting into the vehicle body as well as the sound a minivan door makes while in use.
The project kicked off with determining what the ideal motion path might look like. Through close collaboration with the client’s Product Planning team, including on-site visits, Motivo was able to determine a motion path that the client liked and felt would support the goals established for the user testing.
The target vehicle was delivered to Motivo simultaneous to project kickoff in order to facilitate quick iterations of different ideas. With the vehicle in hand, Motivo was able to map out a more detailed motion path that would work with the vehicle body and the original vehicle door without needing a major tear up. The final approach was selected through use case criteria such as ingress/egress, robustness, and targeted interior space accessibility, as well as technical criteria such as integration feasibility, tunability, and packaging volume. The final design was an advanced mechanical linkage that can fold up into the door when closed and open the door in a unique sliding motion without the use of any rails.
Motivo used rapid prototyping techniques to quickly test and iterate the feel of opening and closing the door versus relying solely on computer simulations. There were several iterations of prototype linkages to further refine the motion path until it felt very natural to a variety of testers. With the baseline geometry established and a known packaging volume, the linkage mechanism was analyzed and further optimized for robustness using multi-body analysis software in anticipation of high cyclic use and edge cases such as a child hanging off the door.
Integrating the mechanism was anticipated to be a challenge from the start, therefore Motivo engineers and fabricators worked closely together during the design phase to make sure all designs were manufacturable. Additional support structure was needed in both the vehicle and donor door, and since no additional units were available it was critical that this was done correctly the first time. This coordination between engineers and fabricators led to a detailed risk-reduction testing plan to minimize risk during the integration side. Motivo’s fabricators are exceptionally skilled and the integration went very smoothly.
In three months, the Motivo team went from initial proof of concept to final delivery of prototype. The door mechanism worked so smoothly during the first test runs that no additional tuning was needed. This is a testament to the aptitude, skills, and close coordination between the Motivo design and fabrication teams. The client was very pleased with the outcome and was able to continue their user studies according to their aggressive schedule.