Expulsion

"We wanted to build a robot to test our engineering skills, to build something and see what we could create, and then go up against qualified engineers to see how we compete against them"

- Georgina Henwood

Expulsion is a series of robots which competed in Series 9 and 10 of Robot Wars, entered by Brentwood School's Technology and Physics department. Despite its innovative design, it fell in the first round of Series 9 due to mobility issues, so a new version was built for Series 10 with greater success, finishing third place in its heat, thereby qualifying for the 10 Robot Rumble.

"The number of students now involved in robotics is remarkable and we hope that our school’s team will further inspire students around the world to get into robotics – especially girls."

- Thomas Walland, project leader

Expulsion (Series 9)
"The weapon has the ability to spin one way to slash the opponent and the other way to skewer them, whilst the blades move at an impressive 20 times a second"

- The Robot Wars website

In Series 9, Expulsion used a two-wheel drive system and featured a large box-shaped chassis with a unique curved front end, built on a budget of £1000. Its armour featured several holes in it to save weight, and the robot's top was decorated with flame graphics and the Brentwood School logo. Expulsion's weapon was a horizontal flywheel made out of 10mm steel with four teeth, spinning at 1200rpm (77.3mph). Uniquely, the teeth retracted within Expulsion's disc, and they emerged when the flywheel accelerated. Expulsion weighed 105kg, powered by 4 x 12v batteries. The robot's name was cut out of the robot’s back panel, which was also spiked. However, weight restrictions required Expulsion's steel armour to be thinner than the Brentwood School team intended. The robot could be stranded on its side, and was slow at 5mph.

"The innovative 'blade sandwich' design came about after some unusual brainstorming. Team Captain Georgina Henwood explained: “We were really hungry when we first sat down to start designing. We were thinking about bagels and the whole ‘ring with spikes sandwiched in between’ came out of that train of thought!""

- Brentwood School Roboteers

Expulsion (Series 10)
"Back with a completely redesigned machine, I am looking forward to seeing what they can do with the resources and skills available to them. Team Captain Georgina is definitely a roboteer to watch out for in the future."

- Dr Lucy Rogers

To address the issues with the previous Expulsion, a lighter, more compact robot was built for Series 10. Its shape was unique, with four sides slanting upwards, somewhat like a pyramid. Expulsion's chassis and armour were now considerably stronger, using HARDOX, and the robot boasts an impressive 30 horsepower in pushing ability. The back end of the robot was taken up by two large tyres, which could drive Expulsion from two of its different sides, either when the robot is flipped, or if Expulsion voluntarily turns itself over. This design concept of partial invertibility was previously used by Pussycat. "We went for a spinner on our robot, because it's quick to produce and you can quickly see the results of your hard work. We like to make sparks fly!"

- Georgina Henwood on the team's choice for Expulsion's weaponry

Expulsion's new weapon is a set of interchangeable tool spinners, also known as face spinners. One is a curved bar-style weapon with two teeth similar to those found on the Series 9 version; the teeth, however, no longer retract fully. The weapon spins on the angled face of the robot, like the traditional use of an angle grinder, or a bludgeoner. The bar spinner, with a tip speed of 92mph, takes up a huge proportion of Expulsion’s weight, but can be swapped for lighter three-spoked spinners with either loose swinging blades or chain flails.

The Series 10 Expulsion is much faster than its predecessor, while its weight varied between 70kg and 110kg depending on the weapon and armour configurations used. Some armour panels and exposed wires on the robot are sacrificial, and were designed to be removed upon contact with spinners. "The led wires are 5v and were expected to get ripped off. They were not part of the main electrical system. The panels are also designed to be ripped off. The Armox is welded seamlessly and the panels bolted on are made from HDPE. The edges are supposed to catch to be ripped off to slow spinning weapons"

- Thomas Walland

Expulsion was frequently stranded on the face of its spinner, creating a recurring flaw for the machine. When the weapon is spinning, gyroscopic procession should eventually turn the robot back over, which the robot managed to do in testing, but for a variety of reasons, Expulsion never managed to self-right on the show despite being flipped onto its weapon four times.

Expulsion also fought alongside a minibot, Detention, during its first battle. A wide, cylindrical invertible axlebot with two wedges, it intends to slot its forked wedges under opponents to hold them in place for an attack by Expulsion. The wedges can be raised to different heights, although its exposed wheels are vulnerable.

Etymology
The name Expulsion was chosen due to the team being students, in reference to the idea of expelling a student from a school. Their minibot, Detention, is named in line with the theme of the school disciplinary system, as is the team's other robot which competes outside of Robot Wars, Suspension. The team used the Expulsion name for both of their greatly differing designs in Series 9 and 10 to show the team's advancements in skill and learning.

Series 9
Expulsion competed in Heat 3, where it faced three veterans; Foxic, M.R. Speed Squared, and Heavy Metal. Team Expulsion demonstrated their weapon to Dara Ó Briain using a cardboard model, spinning the model disc in the opposite direction.

Expulsion started the battle slowly, as it could seemingly only turn left, having struggled to enter the arena in the first place. This still allowed the team to get their weapon up to speed, but it was charged by Foxic, and then sustained a direct hit from M.R. Speed Squared. Heavy Metal pushed Expulsion towards Sir Killalot, where it was flipped by the arena spike, landing on its side before being knocked down by Foxic.

Expulsion was rendered fully immobile, and sustained a glancing blow from M.R. Speed Squared. Sir Killalot moved Expulsion from its position, but it took more damage from two M.R. Speed Squared attacks, and was hit one last time when M.R. Speed Squared rebounded off Heavy Metal. Foxic had also been immobilised by the floor flipper, so Expulsion was counted out at the same time, and both were eliminated from the battle, while M.R. Speed Squared and Heavy Metal progressed.

After 'cease' was called, Sir Killalot picked up Expulsion and placed it on the floor flipper, where it was thrown up, although these attacks were not shown on television.

Series 10
"A very bright school team that got taught a real lesson in their group battle last series."

- Dr Lucy Rogers

The brand-new version of Expulsion competed in Heat 5. In its Group Battle, it fought a former Grand Finalist Thor, and the only Scottish robot in the series, Coyote. It entered the arena with its three-pronged spinner, and the minibot Detention. "When we first entered Robot Wars last year, I was a bit, like... ooh, this is like a male-dominated thing. I think coming here has changed my perception. Everyone's really welcoming and really happy to talk to you and give you advice. I would like to see more females in teams, because it just encourages more girls into engineering."

- Georgina Henwood

When the battle begun, Expulsion could only attempt to spin up its weapon before Coyote bolted straight towards it, driving Expulsion into the arena wall and toppling it onto its side. Expulsion had already been immobilised within Dead Metal's CPZ, while Detention became stuck on the flame pit. Dead Metal held Expulsion over the flame pit to burn it while attacking with the circular saw, while Detention tried to break free, eventually grounding to a halt. "Oh no, it's already stuck!"

- Juliette of the Brentwood School Roboteers

With this, Expulsion had lost its Group Battle, but the fight continued between Thor and Coyote, eventually leading to Rogue House Robot being activated shortly after Coyote brought Detention off the flame pit. Dead Metal drove over Detention while chasing the active competitors, and pushed it around the arena for the duration of its attack, prompting Thor and Coyote to exact retaliation on Dead Metal afterwards, avenging the beaten minibot. The battle was eventually won by Thor on a Judges' decision. "They don't like the fact that the school team was bullied!"

- Jonathan Pearce as Detention is avenged

In the Robot Redemption Knockouts, Expulsion faced Team S.Tek's front-hinged flipper, Push to Exit. Extra curved panels were added to the side of Expulsion to assist with self-righting, while parts of the tri-blade spinner were removed ahead of its second use. "You learn different things here than you learn at school, but Robot Wars is a great way of applying the specific knowledge that you learn in each different lesson to a real-world situation. You can't just say 'oh I learned this to do this', you've got to adapt your skills and change for the problem."

- Georgina Henwood

Expulsion quickly spun up its weapon, and Push to Exit crashed straight into the spinner. Expulsion inflicted damage with this hit, but was knocked onto the flame pit where Dead Metal threatened it. Expulsion was slammed by Push to Exit, and then was wedged by it, but Push to Exit lacked a working weapon, and Expulsion was merely held in place. After being briefly locked together, Expulsion reversed off the barely-mobile Push to Exit and delivered a direct hit to the back of the robot. While Expulsion pushed the intermittent Push to Exit, it drove over the floor flipper, and was tossed onto the surface of its spinner, once again immobilising Expulsion in such a fashion. However, Push to Exit did not make any meaningful movements again while Expulsion turned slightly on the face of its weapon. "Expulsion moving, well, momentarily.. twitching, it's still trying to spin and trying to self-right. There is life in Expulsion, but it will go to the Judges to make a decision!"

- Jonathan Pearce

Expulsion was showing minimal signs of movement, and both robots were counted out and sent to a Judges' decision. The unanimous decision went in favour of Expulsion, awarding it a second chance to compete in the competition. Ahead of Expulsion's battle with drum spinner Magnetar, further modifications were made to Expulsion's three-pronged spinner to assist with self-righting.

Fearful of Magnetar, Expulsion spun up its blade and headed directly for the Arena Tyre, activating Fog of War just six seconds into the battle. This worked against the favour of Expulsion, as it afforded Magnetar time to spin its drum up to speed, and when the two robots collided, Expulsion was catapulted into the air by the drum, and it landed on the floor flipper, which threw the 70kg machine even higher into the air, and Expulsion once again landed on the face of its spinner. However, regardless of self-righting ability, Expulsion had been completely immobilised, and laid dormant until 'cease' was called. Dead Metal dropped the beaten machine into the pit. "That was spectacular!"

- Georgina Henwood

Expulsion could still fight in the Third Place Play-off, where it faced Coyote for the second time. The team used their heavier spinning blade for this battle, while Coyote had applied a new wedge designed to resist spinners. Coyote's team were confident, based on their earlier win, while Expulsion had three elongated bars affixed to the robot to prevent it from falling over in battle. "We've added a few more, sort of bars so that we actually can't physically fall over on our face unless we're flown in the air by the floor flipper, so I just have to not drive over the floor flipper."

- Georgina Henwood

Expulsion drove in an arc, and connected with the side of Coyote, ripping away some of its pipework structure, but then drove into the arena wall, where it was pinned by Coyote. Expulsion crashed into another arena wall while fleeing from Coyote, and was pressured by Matilda, before driving into the wall for a third time. "It's all about learning, the electronics, the engineering skills for Georgina and her team, and they've done it so well... you just need to learn to drive!"

- Jonathan Pearce

Coyote caught Expulsion side-on and pushed it into the centre of the arena, but there Coyote suddenly stopped moving, and Expulsion appeared to be victorious. Expulsion landed a glancing blow on Coyote and then drove into Matilda, sustaining two direct hits from the House Robot's flywheel, the second of which once again placed Expulsion onto its spinning blade. Matilda flipped Expulsion back onto its wheels, but the added bars stopped Expulsion from moving out of its own circumference regardless. However, a countdown clock had already begun for Coyote, which secured Expulsion's place in the Robot Wars: Series 10/10 Robot Rumble.

The whole team celebrated, with the school's personal driver admitting to being tearful, while members of the Sub Team encouraged Henwood and her team to repair their robot before its next fight. The 10 Robot Rumble saw Expulsion face Thor once again, alongside Apollo, Big Nipper, Concussion, Eruption, Iron-Awe 6, Sabretooth, Terrorhurtz and fellow school team Track-tion. In order to disguise itself, Expulsion entered the battle having been "camouflaged", using a new scheme of paint to make Expulsion look the same as the arena floor. Their heaviest spinner was used for the second time, as well as the added beams to prevent the robot from falling over. "It's an amazing achievement for Georgina and Team Expulsion!"

- Dara Ó Briain

Expulsion spun its weapon up to speed, and initially tried to attack the back of Terrorhurtz and Iron-Awe 6, but was otherwise largely uninvolved at the start of the battle, being lightly pressured by Big Nipper. After Thor pressed the Arena Tyre, the pit was opened, and Georgina Henwood seemingly had not realised this, for Expulsion, under pressure from no other robots, drove directly into the pit, and was the very first robot to fall in the 10 Robot Rumble, which was ultimately won by Eruption. "Oh no! Expulsion have gone!"

- Jonathan Pearce

Results

 * }

Wins/Losses

 * Wins: 2
 * Losses: 4

Outside Robot Wars
Following Robot Wars, a press release from Brentwood School claimed that the students were also working on "Expulsion: The Next Generation", which referred to the Series 10 version of Expulsion which debuted at Extreme Robots in Manchester, having only attended a Robots Live! event as a backstage display. It was intended to use its new spinning weapon in battle, but the roof of the event was deemed unsafe, and Expulsion fought without a weapon. It did not win any fights, but was held aloft spectacularly by Big Nipper, and held up to blows from Gabriel.

The third version of Expulsion debuted at Extreme Robots in Maidstone, using a wide wedge design, but became immobile in a loss to TMHWK, and later fought Saint and General d'Meaner in two different melees which each contained Trolley Rage, Dozer and Vanquish as additional opponents, failing to move in one.

Aside from Expulsion, the team built a second robot, Suspension, a 70kg robot armed with a set of rear flails shaped into the letters of Suspension's name. It made its live events debut at the Robots Live! event in Burgess Hill, where it was thrown out of the arena by Weird Alice in one battle and immobilised in another against Eruption and Big Nipper. Later in the same month, Suspension competed at the same Extreme Robots event as Expulsion, managing to pick up a combat win.

In September 2017, a new version of Suspension fought with a broad front wedge and loose chains at the rear to allow sit-and-spin tactics while spinners were still deemed unsafe at live events, and fought at Extreme Robots in Colchester but lost group battles to Cyclone twice, TR3 twice, Eruption, Behemoth, Meggamouse, Iron-Awe 5 respectively. The original version of Suspension became known as Internal Suspension, but was thrown out of the arena by Eruption.

Four members of Team Expulsion competed with Suspension in the upcoming Chinese TV programme King of Bots, aiming to represent female engineers with the ultimate goal of becoming "Queen of Bots". Suspension was now equipped with a lifting wedge, the type previously used by Stinger: The Killer Bee and Wyrm.

Trivia

 * Expulsion was first unofficially revealed by Professor Noel Sharkey via Twitter on December 6th, 2016, supporting the presence of female team members. Team Expulsion later confirmed their qualification on February 24th, 2017.
 * Although he was not officially a member of the team, the Expulsion project was led by Design & Technology teacher Thomas Walland.
 * Footage of Explusion's chassis being welded is also used for the opening/ending titles for the Facebook video series, How to Build a Robot.
 * Footage of Expulsion's application video for Series 10 was also used prominently in an official trailer for the series.