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 and not another? Why this size? Why so many holes? Well, there’s no single way to approach a robot’s design. What works in some situations, might not be a good solution for other purposes. See what guided us during the process of designing the mobile robot.
It all started a long time ago, with Project Scorpio, which is a series of Martian rovers as a part of the OFF-ROAD student association. The association team built a remotely-controlled, 50 kg rover (aforementioned Scorpio) for geology and life sciences concerning space exploration. It served as a prototype for the 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. So, back in the day, when Szymon was still a member of the association, he was redesigning Scorpio to be a four-wheel rover. "The thing is, when designing the rover, considering its size, etc., the spectrum of possibilities is so large that you don’t know what to choose, what to base your design on. So then, you have to impose something. I imposed it should be 1 m in size basing the idea on a random object I grabbed from my desk and started designing. And it just happened that the rover of this size fitted in the elevator, through the door, in a car without disassembling the robot." says Szymon.
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 dimension as something to facilitate the transport of the robot. Then, going far ahead, first with Turtle and then Leo Rover, the point was that it was supposed to be a robot that one person could easily transport. So basically, with Leo Rover, you can just lift it and there’s no problem with it being too heavy and too big to carry it, which altogether translates to the user’s safety. 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 it. The end result of designing the mobile robot was that Turtle, and later Leo Rover, became 4 times smaller than Scorpio from which the idea arose.
The thing with the rover’s size was also a matter of the wheel's design because 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. The robot has to look and feel like something robust and firm, which means it needs to be quite heavy, but in such a way that you can easily carry it.
In general, Turtle became a spiritual successor of Scorpio as it was the culmination of what some of us had learned while creating Scorpio, and served as the base for us to continue developing hardware and software for mobile robotics, a mantle later taken up by Leo Rover.
When it comes to the shape of a Leo Rover, the outline is square, at least at first glance. In fact, when you look at the spots where the wheels touch the ground, it’s actually a rectangle which is 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 turn in place. And the looks? Well, the robot’s pretty angular and nerdy. But that’s 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. But 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 Leo Rover (see the most popular add-ons people use with their Leo Rovers). The holes are on top of the robot and the actual electronics are encased underneath. The idea is that what you see on the outside, is just the rover’s shell, kind of like an exoskeleton. The actual electronics and all the robot’s guts are safe and sound below that, where no water can touch it. So, you could say that a 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, about which you can read here.
That’s one thing. The other 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.
You might not realize it but there are more mounting spots on the rover other than the holes at the top ;) There are also mounting grooves on the Leo Rover’s suspension beams to which you can attach Rexroth or V-slot inserts and mount things on them like lighting equipment, various sensors, and so on. It didn’t use to be like that, though. Earlier iterations of Leo Rover weren’t equipped with grooved suspension beams.
Now you know why the Leo Rover mobile robot looks the way it does. Hopefully, in this article, we’ve answered all the questions regarding the vehicle’s design that have been bothering you. But keep in mind that the Leo Rover robot is constantly going through an ever-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 ;)