Electric Standing Chair

The brief was just one product idea, nothing else: an electric mobile standing chair for seniors with limited mobility, developed in the Mechatronic Product Development course at Munich University of Applied Sciences for the fictional startup mobi. Everyone on the five-person team developed their own concept. Mine steered by weight shift like a Segway and sat on a saddle, while the multi-motor ball drive I proposed first got dropped again. The partial solutions from all five concepts got evaluated and assembled into one new combined concept instead of just picking the best single one: the saddle seat from my concept stayed, the steering didn't.

Version 1 split into three assemblies: cross base with drive, mid-section with tilt and height adjustment, and seat shell. That's what the first rough cost estimate under VDMA overhead costing was built on. A bolted two-piece part became a single casting, and the wheel cover now clips in instead of being screwed on — material efficiency, less post-machining, a cheaper alloy and a reused mould brought the unit price on paper from €32.50 to €23.44. Three more levers followed: the sprung footrest with its brake button gave way to a simple button, the joint plate got welded to the seat shell instead of bolted, and a standard joint with a clamp lever replaced the stepper motor, gearbox and custom casting on the tilt adjustment — with the four on the cross base, seven levers across the whole project.

Then came two real quotes for the identical part, further apart than any internal estimate: CASTFAST calculated €274.60 in permanent-mould casting, assemblean €131.87 in die casting. The estimated sale price still dropped from €3,275 to €2,786, even as material costs rose, because real supplier quotes now reflect an assembly-based startup's cost structure better than the generic VDMA template did. A physical prototype of version 2 is still the next step.