Bringing Autonomy to Combat Robotics

If you’re not familiar with the show BattleBots, imagine 250lb robots fighting “to the death” in 3-minute matches, and you’ll get the picture. Robots armed with swinging hammers, spinning blades, and beastly flippers do their best to destroy their competition. Season 3 launched on May 11, and it’s definitely an exciting time in this world of “Combat Robotics.” Humans have traditionally driven the bots — controllers in hand, and intense faces pressed up against the 1 1/2”-thick polycarbonate walls of the arena — but autonomy is on the horizon, and it’s a path I look forward to taking.

How do I know so much about BattleBots? I am bot-builder, and I was there this year, competing for the Giant Nut! When I’m not building fighting robots, I am an instructor for the Robotics Software Engineer and Flying Car Nanodegree Programs at Udacity.

The pits, where the builders repair their robots, open at 7am in the morning and run until midnight — and they are always busy! Teams are racing against the clock to replace their burnt out motors, fix their melted wiring, and repair their frames with the assistance of the ever-helpful sponsors Tormach and Lincoln Electric, who bring fabrication equipment onsite. Standing in the pits, you’d feel like you’re inside of a busy bee hive — everyone is focused on their own task, but working towards a common goal — making this season the best one yet!

My first robot (Season 2)

The first robot I built for BattleBots was named Bucktooth Burl, for the sharp teeth that the bot spun at 2,800 rotations per minute.

My team and I put Bucktooth in the BattleBox in Season 2, and pretty quickly realized there was room for improvement. Bucktooth had one great fight …

… but there were several flaws in his design. Then, Season 3 came along, and I had another chance! However, the build timeline was too short for me to build a new bot. Luckily, a veteran builder named Jerome Miles offered to let our team borrow his robot, Red Devil. This was a great opportunity to get to know another robot and learn from its design.

Community and collaboration

It is these kinds of opportunities that make our field such an exciting one.

When you combine groundbreaking technologies, real-world opportunities to iterate in real time, and a creative and supportive community eager to collaborate and learn together, it’s amazing what can be achieved.

Whether I’m wearing my bot battler hat, or acting in my capacity as a Udacity instructor, the same things apply, and in fact, Udacity’s robotics community is one of the most inspiring aspects of my job. The passion uniting our aspiring roboticists is both contagious and exciting, and there is a pervasive spirit of innovation that easily matches what I experience in the world of BattleBots.

Innovation

When building a robot for the competitions, the real innovation lies within the mechanical design. How will you spend your 250lbs? And what will your active weapon(s) be? Every builder takes a different approach to the design of their robot, depending on what materials they prefer, what equipment is available, and their personal preferences. This made “borrowing” someone else’s robot a unique experience, because unlike every other builder who would have spent the weeks preceding the competition building their robot, our team showed up to the pits with almost no idea of what we’d find inside of Red Devil!

My new robot (Season 3)

Red Devil runs on treads, instead of wheels. Both of its tread pods are powered and controlled independently, not only from each other, but also from the main body as well. The advantage of this is that if one system is damaged, the remainder of the robot can continue to operate. In BattleBots, loss of motion can get you counted out, so it’s important to have redundancies in your system!

Red Devil’s weapon is a set of clamps and a saw blade. In addition to that, the robot’s body can lift into the air (or, on the contrary, it’s track pods can lift up). Red Devil is designed to drive up to another robot, clamp on to it, lift it off its wheels, and then saw into it — hoping to hit a battery, wire, or other vital component.

Red Devil is a rather unique robot in how its weapon and actuation have been designed, but there are many ways to be innovative at BattleBots! Some roboteers choose to split the 250lbs across several robots, creating a multibot army that can attack it’s opponent from two or more sides at once. Others are starting to employ autonomy.

Software, autonomy, and the evolution of BattleBots

The robot Chomp, which is armed with a mighty swinging hammer, uses a lidar camera and an onboard computer to optimize its hits. The lidar gives the robot the ability to measure distance to its opponent, allowing it to trigger a ‘chomp’ when the opponent is directly in front of it and at a predetermined distance away. This way, the hammer hits the opponent precisely where it hurts the most! This software addition was incredibly effective when Chomp destroyed one of Bite Force’s chain links, disabling their weapon.

This year, Chomp utilized a technology called an AprilTag to track its robot’s precise location in the BattleBox. The two dimensional tag that resembles a QR code is attached to the robot, and a machine-vision camera mounted above the arena can then track the robot during a fight. Such technology allows the user to know the full (6 degree-of-freedom) position and orientation of their robot, allowing for even more complex and precise automation.

Automation is the route that I’m hoping to take. Aside from my dislike for driving, I believe that with the technology available now, an autonomous bot will easily be able to out-maneuver a human-controlled bot. When’s the last time that you did a reaction-time test at a science centre or arcade? The average reaction time for a human to a visual stimuli is a quarter of a second, while for a robot it’s at least an order of magnitude faster!

In the BattleBox, every second counts, and an autonomous robot can apply the precise controls required to zip around and hit its opponent on the side, potentially ripping off an unprotected wheel or hitting the weak spot in an opponent’s armour.

BattleBots and Udacity: A virtuous circle

It’s an exciting time for BattleBots as the sport evolves, and I’m eager to see what happens as we add another level of complexity that includes computer vision and controls. It’s particularly exciting for me personally, because while I knew my outside experience would inform my contributions to the curriculum of our Robotics Software Engineer Nanodegree program, I didn’t foresee the extent to which I would actually learn from the program myself, or how much that would inform my BattleBots efforts!

If Computer Vision and Controls are concepts that you’d like to learn more about, I highly recommend looking into our Robotics Software Engineering Nanodegree Program. In addition to creating some of the content, I also learned from the lessons my peers were creating. In fact, prior to going through the Perception module in the program, I had no idea how to use information gathered by a camera. Now, I feel prepared to use camera feeds to improve and even automate my future BattleBots!

The Future

I hope that you’ll be rooting for Red Devil as you watch Season 3 of BattleBots, and on the lookout for our new autonomous bot if and when Season 4 comes around!

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images courtesy of BattleBots Inc.