I am Dattaprasad, currently working as a Industrial Automation research engineer on an Indo-UK project, near Chennai. I am basically from a small town in Goa where I did my engineering and followed it with Masters from Manipal.
Recently, we had our college Alumni meet. All college buddies agreed to meet-up everyone in the college campus, to relive those crazy memories we created in the campus and to know what everyone is up to. We were all freaking excited for this event. That day, I met this senior guy (name not disclosed due to privacy reasons). A great guy with a good sense of humor and a humble person. The last time I checked up with him was in 2015 when he worked as a full-time professional photographer in Goa. He showed me some of his work then. It was quite impressive to see a guy from a small town earning his way to be a great photographer. I was excited to meet him, again, probably to get some good photos clicked (for my Instagram, of course!).
But when I saw him in the Alumni meet, he was bound on a wheelchair. I was really surprised to see him this way. Later he revealed that he met with a car accident and got his legs paralyzed. He has lost his ability to walk. I felt awful to hear this. He had to be carried everywhere on his wheelchair. The worst part was getting over the stairs. Our college lacked the facility of lifts and ramps. Four of us had to carry him up/down, even in ground floor, for which one to had to climb 2-3 steps.
As an hands-on automation engineer, I have been thinking of similar needs for others, especially elderly people. In India, most of the elderly people suffer from arthritis or ailments which makes it very difficult for them to climb stairs. In fact, most of the towns and cities in India have apartments/flats with 2 - 3 floors and have no lift or ramp facilities. This severely hinders the movement of elderly people outside their home as they have to be otherwise dependent on others to go from one floor to another. In fact, this affects their self-respect which further deteriorates their condition.
Presently, there are very few existing staircase climbing wheelchairs in India and globally. However, they are exorbitantly priced (above 2,50,000 INR or 3000 USD). This makes it very difficult for 95% of the Indian elderly society to procure it.
Keeping this in mind, I started planning on a low-cost yet efficient solution that will work in Indian environment. Around 6 months back, I was involved in developing a prototype of a 6-wheeled, all-purpose vehicle that can move in different conditions, including rough terrains, watered roads and can climb few steps, etc. The video is available on YouTube here.
I am now working towards using this idea and developing a 6-wheeled wheelchair. However, there are many things to be taken care of. For instance, most of the steps in flats/homes have 10 to 11-inch width and 4 to 4.5-inch depth. In case where the stairs are in the form of a helix, this width further reduces. Hence, it is imperative to build a model which can adaptively bend with precise control in speed. This will not only involve bringing in hydraulic based suspension, but also require wheels with good grips, high torque motors, good sensors, controllers and other electronics, including small display screen.
I have done the engineering design part and have just started making it. I went to the shop-floor and have prepared the structure (Image of basic structure is shared above). I am also in touch with professors and a medical doctor to get the exact requirement, both from engineering and medical perspective and so as to design it, keeping in mind the user's comfort.
I realize that building such a prototype for the first time would result in some changes and trials before making the full prototype. I am expecting an expense of nearly 2 lakh rupees(INR) for this prototype. The cost-breakdown for the components required is as follows:
1) Lithium-Ion battery with charger(24v, >10Ah): Rs 8,000 - 10,000
2) High torque motors(24V, Rated torque 20-30Kgcm): Rs 7,000 (approx) each x quantity needed is 6 = Rs 42,000
3) Hydraulic Suspension system for balancing the system (to lift a weight of 70-80 kg): Rs 7000 each x Quantity needed is 2 is Rs.14,000
4) Electronics circuitry and related components: Rs 15,000
5) An online dashboard for remote control and monitoring: Rs. 12,000).
6) Mechanical structure (Shafts, wheels, miscellaneous): Rs 15,000
7) Workshop cost (Cutting, welding, making customized parts for fixtures): Rs 15,000
8) Re-ordering some components in case of damage: Variable (say, 15,000)
This approximately comes to about Rs 1.5 lakhs.
Eventually, once successful, the actual cost of design and manufacture would be around 1,00,000 Rs (1 lakh rupees)