Learn the reasons behind the mobile robot’s design.
Have you ever wondered why the Leo Rover robotic platform is designed the way it is? Why this size? Why so many holes? Well, there’s no single way to approach a robot’s design. What may work well in one situation, might not be suitable for another. See what guided us during the process of designing this mobile robot.
The story of the Leo Rover’s design can be traced back to Project Scorpio – a series of Martian rovers constructed by the OFF-ROAD student association at Wrocław University of Science and Technology. The association team designed a remotely-controlled, 50 kg rover (the aforementioned Scorpio) for geology and life sciences concerning space exploration. It served asa prototype for students to test new technologies and work on their team skills, aiming at preparation of the concepts for future manned exploration of the Red Planet.
Back in the day, when Szymon was a member of the OFF-ROAD association, he redesigned Scorpio to be a four-wheel rover. "The thing is, when designing a rover, the spectrum of possibilities is so large that you don’t know what to choose, what your design should be based on. So then, you have to impose something. I imposed 1 m in size, which was based a random object I grabbed from my desk. And it just happened that a rover of this size fitted in the elevator, through the door, in a car without disassembling the robot." – Szymon says.
So, the idea was to end up with a compact rover. Sure, you can build a huge robot, but then good luck with taking it out of the workshop or a car. And that’s how we started thinking about the dimensions as something to make the transport of the robot easier. Then, going far ahead, at first with the Turtle and then Leo Rover, the point was that it was supposed to be a robot that could be easily transported by one person, which translates to the user’s safety and convenience. But it also couldn’t be too small – just big enough to mount additional components on it, such as cameras, LiDARs, and so on, and yet, compact enough to carry them. Ultimately, the Turtle, and later, the Leo Rover, became 4 times smaller than Scorpio from which the idea arose in the first place.
Another aspect the Leo Rover's size depended on was the wheels' design as their size needs to be suitable for the size of the vehicle itself. The robot’s wheels are the most difficult part to design and since we didn’t want to manufacture tires on our own, the Leo Rover’s wheel is actually built to fit a pre-made tire from RC cars.
As mentioned, the robot couldn’t be too small and the same goes for weight – it couldn't be too light either. It was crucial to us that the rover looks and feels robust and sturdy, which required a certain level of heftiness, yet still allowing for carrying it with ease.
In general, the Turtle became a spiritual successor of the Scorpio as it was the culmination of what some of us had learned while creating student association rover and it served as the foundation for our team to continue our hardware and software development for mobile robotics – a mantle later taken up by the Leo Rover.
When it comes to the shape of the Leo Rover, its outline apears to form a square,but on closer inspection, the spots where the wheels touch the ground form a rectangle that’s wider than longer. It’s like that because the wheels don’t touch the ground at the very ends, but in their center. The square(ish) shape allows the robot for differential turning, meaning, it’s able to pivot in place.
And the looks? Well, the robot’s pretty angular and nerdy. But that’s exactly the point – all those cables are visible on purpose so that it kind of resembles the Mars rovers – a lot of metal here, a lot of cables there ;).
We’ve pointed out many times how robust, reliable and watertight the Leo Rover mobile robot is. You’d think that a rover with a lot of holes is anything but watertight. Not in this case. So, why so many holes in the first place?
It’s simple. They’re mounting holes that allow you to attach various add-ons to your Leo Rover (see the most popular add-ons people use with their Leo Rovers). The actual electronics and all the robot’s guts are safe and sound underneath, where no water can touch them. The idea is that what you see on the outside, is just the rover’s shell, an exoskeleton if you will. So, you could say that the Leo Rover’s design lies in the concept of a turtle, which is the very reason why it used to go by the name Turtle.
That’s one thing. Another one is that the robot is constructed in such a way that screams: “mount something here!”. In other words, the Leo Rover’s design is intuitive, right at first glance, seeing those multiple holes, you know that you should add something to it. The design looks unfinished but that’s the point! You’re the developer, so it’s your job to finish the rover by mounting additional components to it so that it serves a given purpose and does the job you want it to do.
Also, you might not realize it but there are more mounting spots on the rover other than the holes at the top. I'm talking about the mounting grooves on the Leo Rover’s suspension beams to which you can attach Rexroth or V-slot inserts and set up things on them like lighting equipment, various sensors, and so on. It wasn't always like that, though. Earlier iterations of the Leo Rover weren’t equipped with grooved suspension beams.
After reading this article, you should have a better understanding of the Leo Rover mobile robot’s design and what guided us. But keep in mind that this compact vehicle is constantly going through a never-ending process of development and improvement to be as suitable for your needs as possible, so who knows, its design might change again over time.
With the design matter covered, you might want to check out the process of preparing a Leo Rover to send it to you if that’s also something you’ve been wondering about ;).
