In April 2017, with the generous support of the University of Auckland and Motion Design, AURA sent six members to Louisville, Kentucky, to compete in the VEX Robotics World Championship. The largest robotics competition in the world, this saw over 1,400 teams from more than 30 countries gather together, to crown a world champion. The 62 university teams were split between two divisions, with the champions of each facing off to determine who would be crowned World Champions.
In this year’s game, robots faced off in a 1v1 format on a 4 metre x 4 metre square field, split down the middle by a 0.5-metre-tall fence. The objective of the game was to toss “stars” and “cubes” over the fence to gain points, in a fast-paced game described as “like volleyball, only with 28 objects”.
AURA finished the qualification matches with 7 convincing wins and only a single defeat, placing our team second heading into the Elimination playoffs. From there we faced teams from Michigan and New York, which we both defeated, landing us in our division finals against a team from Puerto Rico. The Puerto Ricans kept pace with their fast and aggressive strategy, however we took a 2-1 win over them to secure our spot in the Grand Finals.
With a 20,000-person audience and many more on the live stream, we were up against team IFR from Florida in the finals. Our 45 second autonomous routine put us in good stead leading into the second halves of the games, where we simply needed to defend our lead. IFR’s fast short-bursts of scoring were effective against our robot, but our greater capacity was able to overwhelm the Florida team. They changed tactics in the second game, employing a strategy to starve us of objects and use their speed in the final 30 seconds to their advantage, however we pulled off a win despite some technical difficulties in the dying seconds, and for the first time became World Tournament Champions.
In the Skills Challenges, AURA pulled off a great 65 points in Driver Skills, but due to slipping by no more than 2 millimetres, lost 8 points on our high hang in Programming Skills. With those 8 points, we would have become university world champions in the Skills Challenges once again, however with the scores being so tight among the top teams, the 8 points we lost dropped us into third place.
Described as “the most winningest team” by VEX organisers and commentators, the Auckland University Robotics Association is now the first and only team out of over 18,000 globally to have won every major world title. Having been in the world finals twice previously (2012 and 2015), we were particularly pleased to have finally broken past second place and claim the champions’ trophy.
Our thanks go to the University of Auckland and Motion Design, for their generous support in assisting our expenses towards this trip. Without their help, this competition would have been much more challenging for our team to fund.
Videos of the two finals games can be seen here:
A video presenting our World Championship robots can be seen here:
A one hour CBS Sports Spectacular of the 2017 VEX Worlds can be seen here:
Full results from the competition can be found on VexDB here.
As a competitive robotics club, AURA always gets asked “Do you building fighting robots??”. Usually the answer is no, however late last year we had the opportunity to design a Battlebot and apply to be on the rebooted ABC show.
The robot we designed, Mango is a ring spinner. Mango would have weighed 115kg, and the outer ring would have spun at 600rpm!
Unfortunately our application was rejected in the final stage of selection due to there being too many similar designs, so for the moment Mango is still only on paper. But we ended up with a lot of design experience, and some awesome looking renders!
We are already thinking about our 2017 submission and working on smaller scale combat robots, so we have exciting news regarding combat robotics to come soon.
We have now released our design notebook for the 2015 season. You can read it here:
This video shows the robots we used at the 2015 Vex U world champs in Kentucky.
Music credit: Macklemore, Can’t Stop Won’t Stop, and especially Robonauts team 118.
With the release of VEX Sack Attack, many teams have begun to talk about using transmissions on their drivetrains. This is probably the best game ever for a shifting drive; speed is needed due to the large field and race for the easy to access sacks (by the goals), and torque is needed for the inevitable push battle that will happen at the end of the game when fighting over goals. Of course, a traditional drive cannot have both speed and torque unless many motors are used, but it seems difficult to use more than four, maybe six, motors on drive this year, as the sacks are rather heavy, and a 30″ reach will be needed for most robots this year. Of course, strafe will also be useful so that you can defend your troughs easily, and quickly move sacks from you opponents troughs to yours.
What Cameron (TooMuchStategy) from AURA has built to help solve these problems is a drive that switches between traditional tank drive and X holonomic. It uses four 393 motors in the the torque configuration, but this number can be easily increased if you have motors to spare. It uses four pneumatic pistons to shift between X and tank drive. It gets about 8 shifts per tank – we have two tanks on at the moment because we have not yet added pressure regulators; you don’t exactly need 100psi to open up the wheels.
In tank mode, the drive ratio is a bit on the slow side, at 1:1. This is, with four 393’s, rather powerful however, and will usually be enough to win pushing battles. In X mode, the drive ratio is slightly over 1.4 (Squareroot 2) when traveling forwards or straight sideways, and 1:1 when going diagonally – see the “Why is X-Drive Faster” article by Oliver. This makes it highly maneuverable.
As for navigating over or around sacks, in tank mode, driving over sacks is very effective The wheels can easily climb over the sacks. In X mode, sacks can get dragged along with the robot as the wheels try to push them sideways. This system has an advantage over other holonomic systems in that it can switch to tank mode to drive over sacks, then switch back to holonomic mode.
Double Cheese was one of the robots that we built for the 2012 Vex Robotics World Championships College Challenge, and played as part of the AURA2 team which placed 11th after qualifications and finished as the quarter-finalists.
Double Cheese gets its name from the wedges on the front of its chassis. These allow it to drive through an isolation zone that is cluttered with lots of objects by forcing those objects upwards. Double Cheese uses an H-drive. Forward motors are four 393s (torque configuration) geared 2:1 for speed on 2.75” wheels. Strafe motors are two 269s geared 1.5:1 for speed on 2.75” wheels. These ratios are equivalent to 1.4:1 and 1:1 on 4” wheels.
The lift is a 6-bar designed to be able to score on all the 30” goals (both sides of the fence) on a college field, meaning it needs to be slightly taller than a high school 6-bar. To help achieve this, the long bar of the 6-bar offset by bolting it to the shoulder gear away from the centre. The 6-bar is also built slightly off parallel so that the ramp is at a lower angle near the bottom of its range and at a steeper angle near the top of its range. The lift is driven by four 269 motors on a 1:7 reduction (torque) with rubber band assistance. Two 269 motors drive 30-tooth sprockets as side rollers, with a 30” ramp for a six-object capacity. Other features include pneumatic drop-down intake rollers for descoring, and rubber band netting to prevent objects becoming stuck on the robot where they would prevent the lift from lowering.
Drive: 4x 393 in torque gearing at 2:1 on 2.75″ wheels and 2x 269s at 1.5:1 on 2.75″ wheels
Lift: 4x 269 at 1:7 Offset 6-bar lift
Intake: 2x 269 side sucker intake (30-tooth sprockets)
Pneumatics: Used on the intake to allow it to drop roughly 90 degrees for descoring top objects
Video of Double Cheese driving around the lab: http://www.youtube.com/watch?v=E0yphqVRWLA
Videos of Double Cheese playing in matches at the World Champs: http://www.youtube.com/playlist?list=PL0B00CF593F9116E9
Dragon was one of the robots that we built for the 2012 Vex Robotics World Championships College Challenge, and played as part of the AURA team which placed 4th after qualifications and finished as the finalists.
Dragon competed in the isolation zone. Dragon is a unique robot that has a backwards six bar in order to get more height and forward reach as it lifts. The backwards six bar also helps the arm not to stick out so far when it is scoring in the 20” goals. Dragon is not ideal for high school competitions because it cannot score 11.5” goals or the far 20” goals, although it can score the 30” interaction goal from isolation. There is a descoring fork on the back of the ramp. Because isolation robots are purely isolated in college, not many motors are needed for pushing power. Dragon can hold up to 6 objects.
Drive: 4×393 4” drive wheels internally speed geared and 2×269 2.75” strafe wheels 24:15 (1.1:1 relative to 4” wheels)
Lift; 4×269 backwards six bar lift geared 1:7
Intake: 2×269 side sucker intake (18T sprockets)
Video of Dragon driving around the lab: http://www.youtube.com/watch?v=-Qd2mQqr6vw
Videos of Dragon playing in matches at the World Champs: http://www.youtube.com/playlist?list=PL0B00CF593F9116E9
Woodpecker was one of the robots that we built for the 2012 Vex Robotics World Championships College Challenge, and played as part of the AURA team which placed 4th after qualifications and finished as the finalists.
Woodpecker was the extension of one of our first interaction robot designs, Carwash. Carwash was designed to be an interaction robot which colour sorted objects in the interaction zone, and passed to the isolation robot. We later realised that it was better to also have the robot scoring in the closest two isolation 30″ goals. For this design, we used what we know works: A very long six bar. Furthermore, we had recently aquirred mecanum wheels, and strafe was a good bonus for this robot as it would be able to easily score both 30″ goals autonomously.
Drive: 8 Motor drive (6x 269, 2 x 393, 1.2 Drive ratio)
Lift: 2 x 393, 1:7
Intake: Side suckers with folding out front ramp, holds 5 – 6 objects.
Scores two closest 30” goals in the isolation zone from the interaction zone in autonomous with 1:7 lift
8 motor drive with strafe, 1.2 drive ratio with mecanum
Video of Woodpecker driving around the lab: http://www.youtube.com/watch?v=sJdOjerj1vY
Videos of Woodpcker playing in matches at the World Champs: http://www.youtube.com/playlist?list=PL0B00CF593F9116E9
Quetzalcoatlus was one of the robots that we built for the 2012 Vex Robotics World Championships College Challenge, and played as part of the AURA2 team which placed 11th after qualifications and finished as a quarter-finalist.
For one of our teams, we wanted our interaction robot to put all the objects from the interaction zone into our isolation zone. Quetzal was the design that we came up with to do this. It uses a 18 inch wide top sucker to pull up to ~10 objects into the robot, then has a rotating, misaligned 4-bar to lift all of them over the wall. This lift is used because it is very efficient, because none of the objects are lifted very far. Even though it only has two 393’s on the lift, it can lift about 9 pounds over its back.
In addition to this, it has two wings that pneumatically unfold, in order to have more capacity. When unfolded, the robot has a width of about ~26 inches.
Drive: 6x 269, 2×393, geared at 2:1 for speed on each side, on 2.75” wheels.
Arm: 2×393 at 1:7. Only needs elastic when lifting very large loads.
Intake: 2×296, 1:2 for torque
Wings: One pneumatic piston each side, allowing individual control.
Sensors: Quetzal has by far the least sensors of any of our college bots, using two shaft encoders, three potentiometers, and three bumpers.
Video of Quetzal driving around the lab: http://www.youtube.com/watch?v=Sw3b8EiXKwI
Videos of Quetzal playing in matches at the World Champs: http://www.youtube.com/playlist?list=PL0B00CF593F9116E9
It’s a CAD-ed version of Java! Java was one of the robots that we built for the Robot World Cup in October 2011, and a lot of teams were interested in the new lift mechanism and how it worked – so we took our time and used Autodesk Inventor to produce a CAD version of the robot too.
It’s a STEP file so should be viewable in any CAD program. It’s only half of the robot (but the other half is symmetrical anyway), not coloured, and no descorer, but hopefully it’ll answer those questions about “how does your 4-bar work?” by letting you see the detail up close.
More information Java itself (with real life photos) is here: