Ian Visser sometimes lies awake at night, brooding about a giant crab-like robot that tears apart its prey with massive pincers before tossing the remains into a flame-belching pit. When his attention lags, a grinning mechanical nightmare looms into view, poised to smash and destroy.
Visser concedes this isn't conventional dream material for a happily married man with two kids and a house in the suburbs. Then again, there's nothing normal about any of the roboteers who compete in the hugely popular slugfest that is Robot Wars. The British-made television series has been drawing many thousands of South African DStv viewers with its regular dose of electro-mechanical wizardry and bloodless mayhem - and there's more to come.
Now living in Manchester Visser studied computer science at the University of Cape Town. After some years with an IT company, he and a friend invented a software development tool called Doddle, which was used to develop a number of systems for Nedbank. Doddle was sold to a Dutch bank in 1987, after which Visser became involved in a three-year project to build their entire banking system.
Thereafter came a couple of memorable adventures. The first was his marriage to Ingrid (the union produced two children, both enthusiastic roboteers). The second was a 30 000km overland trek from London to Cape Town that lasted six months and involved two Jeep Wranglers, two trailers and seven friends. In the meantime, Doddle was sold by a Dutch software house to six other European banks.
After running a small consultancy for 10 years, says Visser, he's now dabbling on his own - an occupation that requires him to spend three days a week in Holland, working for the same Dutch bank that originally bought his software. This time, though, it's a spinoff package called Gampang (Javanese for It's simple). Naturally, Visser calls it Son of Doddle.
Why would a software developer and IT consultant become involved in such an offbeat form of gladiatorial combat?
Says Visser: It started a few years ago while we were watching one of the Robot Wars programmes on BBC2. My son Dominic, then aged six, said Can you make one of those?' Of course, I couldn't resist. Funnily enough, a barrister friend named Richard Hartley was having exactly the same conversation with his six-year-old, Howard. So we decided to join forces - and came up with Crushtacean. The name was inspired by a crab-bot described in Arthur C Clark's Rendezvous with Rama.
They put in about 500 hours preparing for the 5th Robot Wars, and learnt a lot of lessons along the way. As all roboteers discover, it's important to decide on your basic weapon system first, then build the robot around it. We started off in December 2000 with a simple pencil drawing, sketching out the basic proportions and design before mocking up some claws in MDF (a dense composite board).
By January 2001 they were ready to go looking for motors, batteries, speed controllers, bottle jacks and wheels, and by May they had completed a full robot chassis in MDF, having first drawn the various components and systems in TurboCad.
We mounted all the components and tried it out: the performance was dismal. We just couldn't get it to travel in a straight line. But since it all fitted, we decided to press on and cut the aluminium body to shape. After extensive research, we opted for 7075 T6 aluminium - a high tensile aerospace alloy with tensile properties similar to that of steel.
It machines beautifully. You can even use wood-cutting tools on it. In fact, I used a wood bandsaw and routers to shape several components. A small lathe-cum-milling machine was bought to fabricate some of the more complex bits. The whole chassis is held together with high tensile screws there's no welding.
Crushtacean's weaponry consists of two sets of claws actuated by means of what Visser charmingly terms the guts of a three ton bottle screw jack, driven by Litton motors. They are controlled through a unique buddy box system using switches sewn into the back of a pair of gloves.
This gives the operator - in this case, Dominic Visser - a very intuitive human interface. When he makes a fist, the corresponding claw closes very quickly; when he opens his hand wide, the claw opens up in sympathy.
Says Visser: The claws can close in two seconds with a force of about 200kg - certainly enough to lift an opponent and render it helpless. Crushtacean's weight distribution was designed to partly counterbalance an opponent's weight on its wheels. This gives Crushtacean better traction and allows us to manoeuvre our opponents into the pit. Anyway, that's the theory.
An interesting feature of the drive train is the use of counter-rotating wheels top and bottom. This has several advantages: it requires less space, the forward motion remains forward (although left and right steering is reversed), gyroscopic stabilisation works both ways up (invertible robots that use the same wheel when inverted cannot use a standard gyro, says Visser, as the robot goes mad when upside down), and the smaller wheels offer a smaller target.
In Crushtacean's case, our main concern was the limited space available. After dreaming up all sorts of complicated mechanisms to drive the top wheel, the final solution was very simple. The top axles float in a vertical slot.
When inverted, the weight of the robot is still on the drive wheels, which ride on top of the trapped' floating wheels below. The friction between the two rubber tyres is far greater than that of tyre to floor, so maximum traction is always achieved.
Crushtacean's upper and lower domes were pressed by a company that originally manufactured steam boilers. By August 2001, the robot was finished - just in time to qualify for the fifth Robot Wars series as representatives of South Africa. But it was far from perfect: it still couldn't be steered in a straight line.
Their battleground was a custom-designed arena in a cavernous TV studio, where the radio-controlled robots went head-to-head (actually, most of the
battlebots don't have heads) to the accompaniment of frenzied cheers from supporters in the audience. Any robot that strayed from the designated fighting area was fair game for the so-called House Robots - seriously mean machines that went by such names as Sir Killalot, Dead Metal, Sergeant Bash, and Mr Psycho.
While Ian prepared for battle with the radio control unit, Dominic (now 10) donned the virtual reality gloves that allowed him to remotely control the robot's claws from a glassed booth above the arena. His sister Michaela, 11, as her father put it, supported us with limitless enthusiasm.
Their first opponent - in a qualifier aimed to determining their robot's fighting and crowd-pleasing skills - was a robot called Edgehog, a 100 kg beast armed with a low-pressure axe. Recalls Visser: Our tactics at that early stage were quite primitive. We relied on the natural Brownian motion to smack into our opponent!
That hurdle vaulted, they moved on to the real thing, taking on Robo Chicken (armed with weaponry described in the official literature as pneumatic pecker and full-pressure flipper) in the first round. Crushtacean won on a judges' decision - and it was a very close shave, says Visser. In their second battle, they went up against 10th-seeded Behemoth, a box-shaped robot equipped with a powerful scoop. This time the crab robot won by pitting its opponent - that is, forcing it into a hole in the arena that periodically belched smoke and flame.
Sadly, Crushtacean was zapped in the final heat, when it came up against a relentlessly plain but effective robot called Wheely Big Cheese - armed with a pneumatically powered flipper. Says Visser: We were eliminated when a house robot called Dead Metal cut off our aerial, leaving us without any form of control.
They were out, but not down. The lessons learned in those early battles - including the fact that a model helicopter gyroscope could be used to keep their robot going in a straight line - were absorbed into the new, improved Crushtacean.
I worked really hard on a hydraulic version of Crushtacean, spending at least 500 hours refining and re-engineering the various systems (by this time Richard Hartley had opted out).
Eventually I realised I wouldn't finish it in time for the next round of Robot Wars, so I quickly rebuilt the robot to the original configuration with a week to go. I fitted a gyroscope, added more radio noise shielding and moved the aerial between the eyes for better protection. By this stage we had better control, but it wasn't great, and we were still worried about radio interference and range.
Came the 6th Robot Wars, and Crushtacean went through to the first round on a wildcard draw. A successful performance in that four-way melee got them through to the next round, when they took on two-times UK champion Chaos II (it was a draw). Recalls Visser: That was by far the best battle we have ever had. We had them completely on the ropes when I drove into the pit after a momentary loss of control - I believe it was due to radio interference.
Next up was the Dutch version of Robot Wars, for which Crushtacean was renamed Krab-Bot (it sounded more Dutch, explains Visser). They beat Alien Destructor II, Hammerhead 2 and Twisted Metal Evo before finally succumbing to Phillipa, a solid and reliable Belgian-made robot equipped with a flipper at one end and a claw at the other.
But it was in the Extreme 2002 Commonwealth Championship - screened in South Africa a few months ago - that Crushtacean achieved real glory.
Fired up and eager for the fray, it joined in a four-way mêlée to determine who would go through to the second round. When the smoke cleared, Crushtacean and the formidable Panic Attack were still in the game. Visser remembers this battle with particular satisfaction because Crushtacean managed to disable Sir Killalot - a nasty piece of work, say its victims - by pulling out some of its essential wiring.
Came the next battle, and Crushtacean grabbed Corkscrew, dumping it unceremoniously into the pit. The final, according to Visser, was another class act, albeit with a somewhat ignominious finale for the South African team.
This time we were up against FireStorm, a wedge-shaped robot with a scary reputation that uses a low-pressure flipper to throw its opponents out of the arena. FireStorm managed to turn our robot on its side, and from that position there was nothing we could do. It was a freak occurrence, but that's the way it works.
It's not over yet. Visser reckons the
latest version of Crushtacean, this one powered by a small petrol engine and featuring all sorts of interesting hydraulics, is a winner. It all works beautifully. I've changed the radio control system from the Hobby 40 MHz to 459 MHz, which means no more interference problems and a much better range. However, it's still a work in progress.
The new Crushtacean is powered by a 4 kW two-stroke petrol engine (originally from a concrete disc saw) driving two pumps. One is a high volume/low pressure (100 bar) unit for driving the wheels and closing the claws. The second, low volume/high pressure (200 bar) pump gives the claws 6 tons of grip at the centre and 3-4 tons at the tip).
The wheels are connected directly to hydraulic motors and controlled by electro-proportional valves for speed and two-way solenoid valves for direction.
The electronics side of Crushtacean has seen the most changes over the past two years. The receiver is now mounted in a shielded box, a small tuned aerial rests happily and safely between the robot's eyes', there's an additional solid state RC interface card from 4QD to
handle the claws, the wires are now twisted and carried inside grounded, flexible conduit tubes, the main electrical box has been painted with a conductive paint for extra shielding, and the gloves now connect to a small printed circuit board powered from the Trainer or buddy socket.
This has a small PIC microprocessor that simulates the pulse train normally received from a Trainer's radio set.
Building a competitive robot is an expensive exercise, says Ian.
A lot of it depends on what you have access to in terms of tools and materials. Remember, this is rip-off Britain. Things are very expensive here. We spent about R56 000 preparing for the 5th Robot Wars, including about R22 000 worth of tools (a lathe, bandsaw and so on) and a lot more since. On the other hand, membership of a golf club over here can easily cost as much, and often much more.
Would a South African version of Robot Wars attract as big a following?
I keep saying this I think it would do very well in South Africa. It does, however, take a while to catch on. To my mind, it wasn't until the 4th Robot Wars that this thing really hit the big time. If you think about it, the production company does very well out of it. They get about 2 000 entries a year, of which about 500 make it to the qualifiers. Then they get to pick the best 100 or so for filming.
Say each team spends R20 000 to R50 000 - that's an investment by teams of R20 million to R50 million that the production company just exploits. Okay, so they have to build the arena, hire the space, build house robots and so on,
but that's it. In fact, they have only
just started offering half-decent prize money. Basically, if you win, it might just cover the cost of your robot.
- The Crushtacean team recently competed in the 7th Robot Wars and so-called World Championships, again representing South Africa. However, the competitors have all been sworn to secrecy until after the series has been televised.