This version is better described as a lab on wheels (or, for that matter, a "monstrosity") rather than a prototype. I was built to test as many options of support elements or steering behaviours as possible - and compare them without participants having to transfer.
Research Prototype
For more systematic and direct comparisons of possible configurations a research prototype was developed that featured a high degree of adjustability in order to be able to match participants’ own conventional chairs’ geometries, an electronic steering system that would allow comparing different steering dynamics and potentiometers for instrumentation of mechanical joints on the backrest.