The Integrated Control Panel

In earlier generations of our prototype, the control panel extended outward as a separate element. Visually, it looked clean and elegant. But in real use, we realized this design left the user’s arm without proper support.

We decided to rethink the layout from the user’s body outward. Instead of treating the control panel as an independent component, we integrated it directly into the handle. This change allowed the forearm to rest naturally on the padded handle, providing consistent support while keeping the controls within easy reach of the hand and thumb.

The Prototype and the Weight:

Our initial prototype successfully hit the target weight of 31.9 pounds. However, during real-world testing and preparation for mass production, we determined that the initial design was not ergonomically viable.

The primary issue was the vertical offset between the control joystick and the armrest. The fact that they not on the same level created an unnatural posture for the user during operation. Therefore, in the final version, we integrated the controls directly into the armrest assembly, ensuring a seamless and more comfortable user interface.

As the design evolved and the chair was tested in real conditions, we identified several areas that were more prone to stress. To improve durability, we reinforced key components—such as the back connecting bar, the handle, and a few other high-load points—using stainless steel. These changes required adjustments to materials across the structure.

As a result, the final weight increased to 37 pounds. While this is heavier than our original target, it is a conscious decision to prioritize reliability and everyday usability over chasing the lowest possible number. 

The Material of the Frame

In the beginning, our dream was ambitious: a chair that felt weightless yet could support the weight of a person with confidence. Carbon fiber seemed like the obvious answer.

Yet we soon ran head‑long into reality. The very processes that make carbon fiber so strong—precise fiber layering, resin curing and autoclave treatment—also make it expensive. The labor‑intensive manufacturing means repair or replacement is costly when a part cracks. Carbon fiber’s brittleness under impact also worried us: whereas aluminum will bend and absorb shock, carbon fiber tends to crack or shatter. For a consumer product that might be tipped, dropped or stowed in a car trunk, these risks felt untenable.

Aluminum came next. This metal has served industries from aerospace to beverage cans for decades because it’s lightweight, ductile and easy to machine. The material’s density of 2.7 g/cm³ is higher than carbon fiber’s but still relatively low. Alloys such as 6061 and 7075 achieve tensile strengths from 200 MPa up to 550 MPa, more than sufficient for a chair frame. We built prototypes, enjoying aluminum’s ease of machining and the way it bends rather than breaks under impact. But as we weighed our early chair frames, it became clear that the product still felt heavier than we envisioned. We wanted to push the envelope further.

That quest led us to magnesium alloys, the lightest structural metals known. Magnesium’s density of about 1.74 g/cm³ means that, volume‑for‑volume, it is roughly 33–35 % lighter than aluminum. For weight‑sensitive applications, magnesium alloys provide an exceptional strength‑to‑weight ratio. But at the same time, It is more reactive than aluminum, making it more expensive and requiring careful processing and protective coatings to guard against corrosion.

The Walker Mode and the Boost Button

To support users who prefer walking with assistance, we designed a Boost button that provides power assist when the chair is used as a rollator. By long-pressing the button, the chair applies a steady forward force.

Early on, we referred to this behavior as “Cruise Mode.” The term is borrowed from cars and scooters, where it typically describes steady forward motion. In that sense, the name was technically accurate—the Boost button does exactly that. Alongside this, we used “Free Mode” to describe walking without power.

However, when real users tried the chair for the first time, we noticed a recurring point of confusion. For both Cruise Mode and Free Mode, users need to switch out of Wheelchair Mode into a single walking state. Within that state, they can either press the Boost button to receive power assist or walk freely without it. The only difference is whether the Boost button is engaged. It would be confusing if we named three modes instead of two.

So, instead of naming three separate modes—Wheelchair Mode, Cruise Mode, and Free Mode—we introduced one clear umbrella mode for the latter two: Walker Mode.

Now the structure is straightforward:

• Wheelchair Mode
• Walker Mode