Pushing a wheelchair usually means walking behind someone. This may be practical, but it also places unnatural distance between the person using the wheelchair and the person accompanying them. Ziggy Mobility developed a different approach: a wheelchair attachment that makes it possible to walk and talk side by side, as equals. What began with one family’s question has grown into a CE-marked medical device. More than 65 Ziggys are now in use in the Netherlands and Belgium.

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A simple question from one family

Going for a walk with another person is not simply about getting from one place to another. It is a moment to talk, connect, and experience your surroundings together. Yet, the design of a conventional wheelchair places distance between the pair, often at the expense of the wheelchair user’s autonomy.

For Nicole van den Dries-Luitwieler and her husband Jan, that distance was particularly noticeable when walking with their daughter Yrsa. Yrsa uses a wheelchair and communicates non-verbally, through sounds, facial expressions and body language. When Nicole walked behind her, she was cut-off from these signals. To make contact, she often had to stop and move around the wheelchair. Nicole, who worked as a physiotherapist at Rijndam Rehabilitation, raised a deceptively simple question: “why could she not walk beside her daughter and push the wheelchair at the same time?”

When a question finds the right people

In 2020, during the COVID-19 pandemic, mechanical engineer Lucy Bennett took on Nicole’s question as a student project at the Delft BioRobotics Lab at TU Delft, under the supervision of Bram Sterke and Professor Heike Vallery. Working largely from home, Lucy’s cat, Ziggy, enjoyed sleeping on the prototype cart she built, causing them to name the project Ziggy.  Job Sesink later joined through the TU Delft honours program. Together with this project, Lucy and Job developed the first custom-made Ziggy for Yrsa and her family.

When a photograph of the prototype was shared through the foundation Ik Ga EMB, a Dutch network for people with profound intellectual and multiple disabilities and their families, the response was much larger than expected. Many wheelchair users, relatives and care professionals immediately recognized the problem and responded enthusiastically to the possibility of walking side by side. This early response convinced the team that Ziggy should not remain a one-off university project. The work grew further through collaboration between TU Delft, Erasmus MC and Rijndam Rehabilitation.

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Making side pushing work

The principle behind Ziggy appears simple: add a handle to the side of a wheelchair so that the person pushing can walk next to the wheelchair user. In practice, this creates an engineering problem. Pushing from the side causes a regular wheelchair to turn, which means the person pushing must then continuously apply force to keep it moving in a straight line. The team solved this by combing a side handle with a specially angled castor wheel. In this way, the wheel generates an opposing lateral force (rather like leaning your bike over to go around a corner) that perfectly counteracts the lateral force caused by side-pushing.

A 2024 study published in PLOS ONE investigated this principle using a three-dimensional dynamic model and experimental tests. A proof-of-concept experiment verified that the modified wheelchair could be pushed from the side without increasing the required pushing force or moment compared with pushing from behind.
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When the laboratory met the pavement

A working prototype was only the beginning. Whilst the first designs worked well on a smooth, level laboratory floor, daily life proved more complicated. The team took six prototypes to ’s Heeren Loo, the largest disability care organization in The Netherlands. More than 20 clients and care professionals took part in the pilot. They used Ziggy in real situations.

Slopes, uneven surfaces, cambered pavements and differences between users exposed limitations that had not appeared in the lab. The pilot revealed that the first design did not yet make side pushing as easy as pushing from behind in all these conditions. At the same time, the team measured how side-by-side pushing affected communication among more than 20 clients and care professionals. The reactions to these communication benefits were overwhelming. That response gave the team a strong reason to continue.

They went back to the drawing board. Instead of asking users to adapt to the technology, they redesigned the technology around what they had observed in practice. Co-creation with ‘s Heeren Loo’s living lab ensured the user needs was embedded in the new technology. Once finished, a second formal pilot at ‘s Heeren Loo confirmed the improvements ‘it conforms to all of the arbo standard’ reported the occupational therapist, whilst clients still benefited from social connection ‘Ziggy ensures that the client maintains contact with the caregiver, which creates a sense of security; this is really important in disability care’ .

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More than a wheelchair attachment

By August 2026, more than 65 Ziggys were in use in the Netherlands and Belgium, predominantly within disability care and care for older people. Ziggys most immediate effect is physical: the person pushing moves from behind the wheelchair to beside its user. But the real change is interaction. Eye contact, conversation and attention to non-verbal signals become easier, and a functional journey can feel more like a shared activity. Someone can provide practical support while still being a friend, relative or companion.

This reflects Ziggy Mobility’s wider view of care. Technology is often discussed as a way to automate tasks, compensate for workforce shortages, or replace social interation. Ziggy Mobility takes a different perspective: technology can also facilitate social interaction in ways which help involve more people in care. A friend, relative or neighbor can support someone’s mobility without the whole encounter having to feel like a formal care moment. This does not replace professional care, but may make it easier for communities to look after one another and keep personal relationships at the center.

This ambition is particularly relevant as care organizations face growing demand, staffing shortages and financial pressure. Ziggy does not solve these challenges by itself. It does, however, offer a practical example of technology designed to strengthen human connection rather than reduce it.

Moving into wider use

Ziggy Mobility is now moving from early market introduction towards wider implementation. The next step is to bring Ziggy to more organizations and wheelchair users in the Netherlands, Belgium and other European countries. Continued feedback from users and professionals will help refine both the product and the way it is introduced.

Ziggy started with one family wanting to be closer during a walk. Its longer-term ambition remains just as human: helping more people move forward together, side by side.

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Learn more

• Convergence Health & Technology Flagship Convergence Human Mobility Center
• The story of Yrsa and Nicole (YouTube video)
• Ziggy Mobility – website
• Scientific publication on the angled castor wheel