MSc. Design for Interaction, TU Delft
Digital Interface Design of Mobility Scooter

Sunrise Medical Sterling Elite2 Plus Mobility Scooter for the Middle Aged Group
Technical University of Delft, Netherlands
Project Type
Client
Team
Skills
Tools
Year
Product Design
Ankita Arora, Avishya Arali, David Cheng, Jitske van Leusen, Qianhui Liu
Rapid Prototyping, Teamwork, Time Management
Figma, Solidworks, Procreate, Miro
2023
Project Overview:
This project aimed to improve mobility solutions for individuals with impaired mobility, specifically those unable to walk more than 500 meters. Over six months, a dedicated team of five undertook a comprehensive design process that spanned three phases. This involved conducting observational studies to understand user needs, engaging potential users in testing sessions to gather feedback, and developing medium-fidelity prototypes to simulate real-world interactions. The project emphasized an iterative design approach, allowing for continuous improvements based on user input.​​​
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Project Outcome:
The resulting redesign prioritizes user comfort, safety, and autonomy, ensuring that individuals can navigate their daily lives with greater ease. A detailed report outlining the design process, findings, and recommendations is available at the end of the page.
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The Challenge?
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Challenge Discovery
The STERLING Elite² Mini Mobility Scooter is a compact and versatile personal transport device designed for individuals seeking enhanced mobility and independence. It offers a comfortable and stable ride with easy-to-use controls and a lightweight frame for effortless manoeuvrability. The brief focused on redesigning a modernized scooter design for young middle-aged (45-60) users that aligns with their lifestyles 15 years into the future. Their daily tasks include commuting to work, shopping and running errands, leisure activities, and travelling.
"The aim is to empower users with autonomy, ensuring they feel in control and safe while riding the mobility scooter. The design should be intuitive, providing clear feedback on its functions to both the user and their surroundings."
Prioritizing a mentally and physically comfortable experience, helping users feel confident and at ease while navigating their environment.

Direction
Three concepts were generated prior to defining the design goal and final direction, each aiming to fulfill all three needs. One of the concepts placed more emphasis on control, one more on comfort, and one offered a more balanced experience. After defining the concepts, various user tests were conducted to understand the need fulfillment by each concept. The explorations of each concept are detailed at the end of this page.
The scope of the project was defined as redesigning the interface but during the exploration of user tests, various other needs were discovered. The other needs were proposed in the design recommendations for future development.
The Process
Design Process
Walk with the ants to follow the design process!
The design process was divided into three major phases. In the first phase, the problem was defined with some interviews and small user tests, the second phase with design goal, ideations, and concept development, and the third phase was the redesign and final prototype tests followed up by recommendations for the company.
Design Goal
To design a control fascia for the mobility scooter that enables its users to lead an autonomous life. The control fascia should offer full clarity over the system’s status and the environment not only providing users not only a controlled experience but a mentally comfortable experience as well. The functions on the control fascia should be intuitive in usage and easy to access during events that require quick reactions & multi-tasking offering users more physical comfort while riding and enabling them to be confident and safe during any and all including emergency situations.

The Current Mobility Scooter
The Design
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Ideation, Concept Selection and Defining Scope
Three concepts were generated prior to defining the design goal and final direction, each aiming to fulfil all three needs. One of the concepts placed more emphasis on control, one more on comfort, and one offered a more balanced experience. After defining the concepts, various user tests were conducted to understand the need fulfilment by each concept. The explorations of each concept are detailed in the report (link at the bottom).
The scope of the project was defined as redesigning the interface but during the exploration of user tests, various other needs were discovered. The other needs were proposed in the design recommendations for future development.
Concept Selection and Defining Scope
The Prototype
Concept Development and Prototype Building
The chosen concept underwent several ideation sessions and design processes, with iterations highlighted on the right. After the third iteration, the features were detailed and the interactions were compared with those of the old scooter to showcase the improvements in the redesigned model. An overview of these elements can be found in the image gallery on the right.
Image Gallery: Development of Prototype > Redesigned Interface > Interaction Comparison
User Test
Curious to know how we tested it?
A medium-fidelity prototype was developed for the pre-pilot user test, with a chair simulating a scooter. After briefing users on its features, they were given scenarios to test its functionality.
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Based on feedback from the pre-pilot, several iterations were made, and cognitive walkthroughs were conducted to refine the prototype for the pilot test. The updated prototype was then assembled on the mobility scooter.
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We invited five middle-aged potential users to participate in the test. They were assigned various tasks, such as exploring a new market in the city, to observing their interactions with the scooter. Each function was analyzed, and System Usability Scale (SUS) scores were collected to evaluate overall performance.
Image Gallery: Pre-Pilot User Test > Pilot User Test > User Test > Analysis (SUS Score)
Through extensive ideation, assessment, and testing activities conducted over the past several months, the team gained valuable insights into the features that users find most useful and appreciated. While some potential features were identified, they ultimately fell outside the focus scope of the redesign and the project timeline. This section offers design recommendations on how Sunrise Medical can further develop the redesign to enhance user experience and functionality.
Finally, the Design Recommendations
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