Mecha art

Dear Evil Engineer: Could I crush my enemies with a giant robot suit?

Image credit: Dreamstime

A villain’s plan for vengeance by mecha violates a fundamental rule of engineering: avoid overcomplication.

Dear Evil Engineer,

I’m short and socially awkward with a receding jawline. I’m 24 years old and I’ve never killed an enemy, or even threatened one without them laughing at me. I’m an outcast. It’s not fair.

While studying for my Evil MBA, the other students called me a second-rate villain whose best chance of scaring someone was to ask them on a date. I graduated a year ago and have since become head of R&D at an evil start-up, Poolantir, but I still want retribution.

I have been leaving sarcastic comments under their LinkedIn posts under a fake name, but the time has come to take revenge to the next level. I want to build a mecha suit so I can crush my bullies beneath my giant robot feet as they beg for mercy. Can you help?


A vindictive villain


Dear villain,

You have suffered terrible rejection and humiliation as a young adult, and you are still carrying the bitter weight of this trauma on your back. This has left you believing you are unable to move on until you have settled the score, but it is best for everyone if you leave these bullies in your past. Only then will you be free to find your own path to personal and professional fulfilment.

However, that is easier said than done, so let’s look at how to build a giant robot to crush your enemies.

Mecha peaked in 2017 when American and Japanese engineers engaged in mecha-to-mecha melee combat and the world’s richest and baldest man Jeff Bezos was filmed operating a 4m humanoid robot suit at an Amazon event. The reality of these publicity stunts was that the combat was disappointingly slow and clumsy, and Bezos’ robotic steed was immobile and had to be supported by chains attached to the venue’s ceiling.

This is because mecha really are highly impractical; a humanoid shape is appropriate when robots are operating in human environments like care homes or restaurants, but otherwise why tether yourself to such an overcomplicated form as the human body?

The most serious problem is that the larger an object grows, the harder it is to support. The square-cube law means that if you double a robot’s height, it will become eight times heavier but only four times stronger. Smaller things (like ants) are strong for their body weight while larger ones (like sauropods and aircraft carriers) tend to be slow and lumbering; consider the sheer amount of energy expended dragging around that mass!

This rule limits size in nature and in engineering; an animal as vast as Godzilla or a structure as large as a Pacific Rim-style mecha would collapse under its own weight. Building a robot tall enough to stomp on humans would be possible but requires extremely tough, light materials and powerful hydraulic actuators. Even then, it is likely to suffer damage on account of the sheer strain on its joints. It would also be slow and unwieldy enough for potential victims to outrun.

Powering such a large structure is another issue. While sci-fi hand waving explains away giant robots with portable exotic energy sources or nuclear reactors, no robot could contain these power sources – which require entire facilities to run safely – and retain mobility. In reality, you could run your mecha on conventional fuel tanks or batteries (although this would seriously limit its range) or solar power (although this would seriously limit its speed).

You seem set on bipedal motion, which – while possible for some human-scale robots like ASIMO – is a challenge and rarity even in nature where it normally only emerges as the primary mode of transport when quadrupeds specialise a pair of limbs, such as wings or hands.

Bipedal motion is not energy efficient; it makes robots more vulnerable to trip hazards and uneven surfaces, more likely to sink into the ground, and the high centre of gravity it requires causes instability. If you are certain however, the most realistic approach to controlling bipedal motion would be through a combination of physical controls (which could be manipulated with the equivalent body parts) and artificial central pattern generators.

Central pattern generators are circuits that drive basic motor behaviours like walking, breathing, and urinating: all those things our muscles seem to be able to do without us thinking too hard about it. These are valuable in biomimetic robots with many degrees of freedom, like mecha. If successfully incorporated, the pilot would not need to provide every minuscule control input to the actuators necessary for motion and can instead concentrate on higher-level controls like accelerating or stomping on enemies. These circuits have been worked into some biomimetic robots, like the EPFL’s salamander-inspired Pleurobot.

While it may be possible to build and pilot a mecha large enough to crush humans, they are likely to be lumbering, unstable, and with very limited range. Building a giant killer robot with many degrees of freedom would break a fundamental rule of engineering: avoid unnecessary complexity! I understand that you want to feel intimidating after suffering at the hands of these bullies, but will the days of maintenance after every (brief) murderous mecha spree be worth it?

Ultimately, my advice is to go for the design that will get your job done most efficiently. Low-slung armoured vehicles like tanks are powerful, uncomplicated, surprisingly fast, and would do a perfectly good job of crushing your enemies. If a tank is not flashy enough, you could consider building a powered exoskeleton to transform into a tougher, more lethal version of yourself. While a mecha is slow and lumbering, an exoskeleton could allow for superhuman agility, endurance, and speed. While military exoskeletons have not caught on yet, research into them is far more mature than research into giant mobile military robots.

The Evil Engineer

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