Barely a month ago, I started working on the idea of a pedal-powered tractor for rice transplanting. This was for my Live-in-Lab project in India. I have just spent four days in the manufacturing workshop in a campus in Tamil Nadu, a 10h trip from my main campus. This post is tells how the manufacturing went on.
After a short month of design work on my project, we are already starting manufacture! Aymeric, who is also doing a project in my lab, and who has already started manufacture announces in a stern voice: “one centimetre”. That is the precision with which our projects are being created. I’m not sure whether I should laugh or cry. As a microengineering student, I feel kind of sad.
In the manufacturing workshop, as well as the “Indian precision”, I also notice the Indian safety standards, or rather the lack of any. Here, the workers are bare feet or wearing sandals, and none of them is wearing safety gloves or glasses. The noise of the machines is deafening, and I often find myself plugging my ears while averting my gaze to avoid the bright flashes from the welding. I would be happy if I don’t become deaf and blind by the end of this project!
The Indians don’t have workbenches: they work directly on the ground. To discuss the design, we crouch besides the parts we’re talking about.
My project is a rice planting machine. When I started doing my research about what already exists, I was disappointed to discover many machines already existed. From cheap machines to massive agricultural monsters, the subject seemed under control. Additionally, while checking out Youtube, I found so many student projects it seemed like all Indian MTech students have to build a rice planting machine. What is the purpose of my project then? I couldn’t see how my work could serve the subject. So I decided to take a radically different approach. Rather than building an average machine that farmers would push or pull across the paddies, I decided to create a pedal-powered machine. Based on a bicycle, with a transplanting trailer, I am convinced that my design could do the job. With countless hours of pedalling in mud as a mountain biking competitor, I knew it was possible to ride through a thick layer of mud. Now I had to prove them.
Apparently, manufacture starts with a prayer. I join my palms in front of my chest, close my eyes, and listen to the prayer in Malayalam. I even recognise some sentences after a month and a half in the Ashram!
We start by building the back wheels. Soon enough, the long strips of steel get bent and welded together as tractor wheels. Yesterday, we went to get a second-hand bike. I like its “old school” looks, but it will soon be disassembled by a gang on young Indian workers. Only the main parts are kept for my design.
The manufacturing is going well, and my Ricycle is starting to take shape! When I arrived in the morning, I discovered with awe that my back wheels were almost finished, and they are impressive. But when I try to lift one up, suddenly, it isn’t as stylish: they are almost as heavy as my travel backpack. At 13kg each (ok, a bit less than y backpack), I start to lose faith in my project… How will my small farmers manage to pedal this prototype through the fields?! A sturdy mountain biking wheel weighs less than 2kg, I would never have imagined mine weighing more than double this figure! My supervisor tries to comfort me: “worst case, we give your system to an ox, it will be able to pull it!”. Cows are sacred in India, the ox gets all the work. I still haven’t understood the difference, but if they say so…
The explanation for this general overweight is the materials used for prototyping. While mountain biking wheels are made out of lightweight aluminium, mine are in made out of heavy mild steel. I’ll have to write down the exact name of it. If we use less material, they would not be solid enough… So they’re heavy. Very heavy.
The other materials and parts used for my Ricycle are mostly second-hand and scrap parts from whatever lies around the workshop. For the gears, we swap the front chainrings and back sprockets. The bike will be easier to pedal with this configuration. For the transplanting system, we find some scrap sawing bands and cut them out. I was imagining having flexible blades, but that was in my ideal designer mind. When I see them hammering the strips to flatten them, I understand they won’t be flexible any more. We learnt in first year’s material class that if you work the metal it won’t be as flexible. Oh well…
My prototype is looking more and more like my computer designs, and I’m impressed. Until now, the biggest project I had made was my robot for the Robopoly contest, which had to fit into a cylinder of 30cm in diameter. The Ricycle isn’t anything alike! The bike is elevated by a dozen of centimetres and the back wheels are one metre apart.
As the day goes on, the project is getting fine-tuned. At first, we set the parts in the right disposition, then we partly weld them (careful with the eyes!), and afterwards the position is adjusted according to additional parts. Everything is getting together thanks to the manufacturer’s work and it is an awesome thing to see. When I have a close look, I notice that it is far from being precision work, and when “fixed” parts are more that one centimetre lose, my microengineer soul dies a bit but then I take a step backwards and am still quite proud of my project.
I feel like a site supervisor, being a snob hidden behind my sunglasses. I have decided to cut myself out by wearing earplugs. My ears thank me for this but the already limited communication is further degraded. The workshop is so noisy that I hurt my ear. And the welding flashes are still as aggressive on the eyes. As I start coughing, I am thinking that with all these metal dust particles in the air I might replenish my iron deficiencies!
During the day, many Indians come to have a look at my tricycle. They try to spin a wheel, to understand how it works… They smile and nod in the typical Indian fashion, and my supervisor explains them what it is. In Tamil. I am almost never included in these conversations, or at the most with a slight nod towards me.
Despite the language barrier, I feel some complicity with the other women in the workshop. They are five, two of them are working on machines. We curiously look at each other, and try a shy smile while nodding our heads. Yesterday, at the tea break, they asked me if I spoke Tamil. Unfortunately, I haven’t tried learning. At the chai break, they show me where to get my cup and make a sign to tell me to sit besides them. One of them speaks a bit of English and asks me some questions. Where I come from and for how long am I here. Even if we don’t speak I appreciate this outreach which makes me feel more accepted than in any of the technical conversations about my project in which I was barely addressed.
The project is being brought into life! With pride, I get on my tricycle and start riding… before derailing after a few metres.
The Ricycle has made its first steps! Or rather, its first wheel rotations. I can’t even imagine the efficiency of the machine, every part is lose. We spend the day assembling and disassembling the wheels and axle to align every part and tighten everything up. Little by little, the parts are welded and lined up with washers, and the wheels don’t have a path difference of 10cm when turned in in opposite directions.
My supervisor brought the axle to the lathe workshop to thread its extremities, and the wheels can now be tightened. This also allows the bike to turn, as one wheel slips while the other is rolling forward when the handlebar is turned. Now the bike is not limited to straight lines! Well this might not be a sufficient permanent solution, as when the bike encounters resistance both wheels slip and the bike gets stuck.
Besides building the tractor-bike, we build the seedling tray. But with the change in dimensions of the back wheels and sprocket, we now have to adapt the length of the connecting parts between bike and transplanter. To solve this problem, I feel lost without my computer, I cannot manage to visualise the best bay to rearrange the parts so that they fit together. Luckily, we move on to another problem, which gives me more time for thinking about the former one.
The bike moves, but is often derailing. Once all the parts have been fixed, it is better, but to guarantee parallel parts when no measurement is precise is a big challenge. We fix small pipes to the frame to align the chain with the sprockets, so it doesn’t derail from the back any more, but from the front! At least now we can pedal a bit further.
Work in progress…
In four days, we managed to build a mostly functional bicycle-tractor! Now that the biggest part of the job is done, the most challenging part stays ahead: linking the transplanting mechanism and make it work!