Since 1998, Tribus has been creating innovative, multi-functional, wheelchair-accessible passenger vehicles by converting existing mini-buses and cars. It embarked on a new adventure in 2018. It developed an innovative compact electric city bus - the Movitas. The company contacted Sioux Technologies to turn the design into a driving prototype.

"The first thing you do is look each other in the eye and ask questions", explains Andries van den Heuvel, Automotive System Designer at Sioux Technologies. "What exactly do you want, what are the essential features and what are the associated technical requirements? Based on this, we created a vehicle model to determine the system layout and to verify the design. We then built the software architecture and added functionalities by means of an iterative process. This makes us responsible for the integration of the modules and components, like the brakes, suspension, lighting, doors, dashboard and electric drive unit. All of these need to be connected and must communicate seamlessly to arrive at a fully functional and safe vehicle. One specific complicating factor was the modular design of the bus. Furthermore, the customer had already made certain choices regarding the parts. This made coordination with the suppliers a key focal point."

High stakes
Van den Heuvel does not hide his enthusiasm for the Movitas, first of all because of the concept. It is a modern city bus, not too small and not too big, with zero emission. It also has four-wheel steering, so it can perform special manoeuvres like parking sideways – or ‘crabbing’ – at bus stops.

"These unique features make the bus highly suitable for use in cramped city centres where manoeuvrability is required, and polluting traffic is increasingly being banned. The risks were high for Tribus. The demonstration model had to be launched at Busworld 2019 to give a clear signal to their new market. We had only nine months to get it all together. We are obviously no strangers to that kind of pressure. A lot of our work is complex and has high stakes. But we are happy to take on that responsibility. In addition to our strict assignment, we had a lot of freedom to help resolve all kinds of engineering issues, by thinking out of the box. We managed to create added value with the purchasing of components and with the graphic design and programming of the dashboard. All of this contributed to the success of this project, and that is a great feeling."