There have been questions of the validity of combat mechs and the shape of police robots before, but the general consensus is that the main reason for a mech to be humanoid is to appear less threatening to the people they are defending.

But realistically, if mechs are to be used by authoritative forces, it is likely that the military will come to the party first, while the local police will be fashionably late. In a combat environment, the idea of having your combat mech honestly seems laughable, current designs suggest drones are superior in almost every imaginable way. There seems to be little to no advantage, at least to me, as to why military robots would be humanoid.

My current thoughts are that perhaps for X reason, it is cheaper, but frankly adding X anywhere on its own in a hard science fiction story is asking for trouble. Is there any logical reason as to why the military would make humanoid combat droids? If there is a reason, what would be the most realistic reason?

  • $\begingroup$ The only reason I can come up with is that the military wants to spite the human right groups, way to go! $\endgroup$
    – user6760
    Sep 17, 2016 at 9:31
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    $\begingroup$ Intimidation of the masses might be plausible. A walking killing machine with red eyes could be more scary than an unseen drone bomber or a quadcopter drone. $\endgroup$
    – Skye
    Sep 17, 2016 at 13:54
  • $\begingroup$ They're nifty. Great recruitment aid, that. Who wouldn't want a shot at piloting one? $\endgroup$
    – The Nate
    Sep 18, 2016 at 1:30
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    $\begingroup$ Being defeated by a flight of stairs is pretty embarrassing. $\endgroup$
    – Mazura
    Sep 18, 2016 at 2:27

6 Answers 6


Genesis of the robot soldier:

Humanoid shapes are pretty hard to make with current robotics. However, depending on the way the robots came to be, it might still be easier to keep the basic humanoid shape than to go the way of simplifying the design. One train that might lead to humanoid robots could be:

  1. Starting at basic human soldiers, they get aditional body armor to keep ahead of the weapon developments
  2. As we armor them up, at some point (pretty soon actually) a critical point is reached, where aditional armor slows the soldiers down more than it protects them.
  3. As a way to increase mobility again, servomotors are added to the joints to help in moving the bulk - and add more armor again. Let's call this "Power Assisted Armor" - or Powerarmor for short.
  4. The steps 2 & 3 are repeated several times, until the armor with all its motors and structural integrity just stands on its own, only lacking the human to control it most times.
  5. Step in some engineer that manages to simulate said human operator by recording the soldiers movement commands in the Powerarmor and then sending them into the armor directly, maybe simply by putting a relay in one 'operator' armor and having the others just repeat what they are told. An early application would be to just remove the soldier from the field and have them control the remote operated Powerarmor from some command bunker, where the operators wear some sort of dummy in suspension with a screen. Safe and sound warfare with humans at the controls is achieved.
  6. The next logical step is to trim down the bulk of the remote operated Powerarmor again, as now it is just a shell and it doesn't need to be armored so much anymore. The result might look more humanoid, but some designs might add the weaponry right into the cavities, like having a gun in the arm and the ammo stored in the torso under the relay equipment.
  7. Since training remote operators takes lots of time and remote operation is prone to being attacked by ECM (Electronic Counter Measures), development might go towards autonomous Powerarmor, which would be just a fancy term for nothing short of an armed, humanoid robot.
  8. Starting here, everything is just refinement of the already existing systems - increased autonomy, possibly filing on the look to look less machinelike and maybe even the addition of synthskin to create infiltration models.

Benefits of Robots over all:

Indifferent of their shape, there are certainly benefits that give robots an edge:

  • Robots are not alive. Loosing a bunch in the battlefield or sending them into hazardous areas to do stuff you don't want to give to people (nuclear waste disposal, bomb defusing, handling chemicals) is pretty standard today, but you don't actually need to be humanoid to do that.
  • With an all-time perfect morale and their possibly better-than-human response times and almost 24/7 battle readyness, they could easily form the backbone of striketeams.
  • Skipping over a system for the robots to speak and adding a little bomb to destroy any data storeage and radio equipment could make the information about them safe in case they fall into enemy hands, either by capture or damage.

Benefits of the humanoid shape

Now, as we have a probable way to get to humanoid robots, what benefits does it have?

  • Humanoid shapes are familiar. As such, people will interact with them a bit easier on a personal basis. A police robot with a face and a humanoid makeup will be asked for help much easier, people will open the door to a delivery robot with a face more happily and they might be much more comfortable with a humanoid teller robot or barkeep than with some arms and a camera that stick out of the wall. Getting commands from a humanoid robot soldier with a gun might look less threatening to the civillian population.
  • The world is made for humans. Most tools and items require a human hand to perate them well, so giving robots at least humanoid hands cuts down the development time of specialized equipment to 0. Still, humanoid hands are not the most perfect tools, we are just used to make stuff good for them. At least the military could just phase out the old weapons that the robot soldiers don't use anymore over the reserve battalions and cut down the need to keep up two sets of weapons (robot weapons vs. human ones)
  • Robots could be made without a sense of self preservation, making them perfect for attacks like the "human wave" where the army just marches on despite having massive losses. Having an unstoppable army of suposedly humans walking up on you however is wrecking havoc with the morale of the adversary side: Soldiers expect enemies to die if they shoot them or if they walk upon mines and then the rest taking a detour or going to cover. They do not expect them to just continiue the march despite loosing an arm or the soldiers next to them falling.

Demands for different shapes

Now, what are the caveats that might demand non-humanoid robots?

  • There are actually shorter ways to robots with battle capabilities, but those are not humanoid! Tracks instead of legs would be a pretty standard thing if the way to robots was not from Powerarmor, but from armored vehicles - which would mean to go via automated to miniaturize tanks. This way would forgo quite much of the humanoid aspect for increased 'battle value'.
  • Humanoid shapes are prone to hazards such as tripping and a quite high center of mass. A human just stays upright because he has a very very precise tilting sensor in his inner ear, which is at least one potence more accurate than those in modern phones (and which reacts with nausea to a shaking floor). Doing something that can do the same is a serious feat of engineering, which might lead to short robots with big feet.
    • For some rewuirements the humanoid shape might be a hindrance! If you want a fast robot, two legs are not a good solution. Four legs or wheels would be a much more stable and faster solution. If you want a strong arm, arms with internal motors are a bad solution, as the best solution would be to use external hydraulic systems to get the best leverage.
  • Military doesn't care how something looks, as long as it is effective. They might choose a simple, tracked variant ofer a fully humanoid one because it is simpler to repair. They might demand stuff that makes a humanoid shape hard to uphold, like jumpjets.
  • Having the weapons being inoperable with human hands would actually be a benefit in military terms, as that would make them inoperable in the hands of enemy troups. In civil unrest/wars and guerillia warfare quite a lot of weapons that the "rebel" side uses comes from the "governement" side's stocks.

Alternate Origins

However, there are also organisations that might clearly prefer humanoid builds, which could be part of the reason why the military adopts just more sturdy models of these branches:

  • Intelligence Agencies. Using a robot spy might need a much more sophisticated machine than the military, but deep cover agents with perfect morale and hard encoded integrity to some rules would cross out double agents.
  • Storefronts. A shop that is operated by a friendly robot pal in a humanoid shape could be open 24/7 with just one payment for the robot clerk and much less personnel.
  • Police. As said, having some basic trust (which does come with humanoid shape and features) is needed for policework.
  • Correction facilities. Sending in robots to pacify inmates could save the live of wardens.
  • Caretakers. Having a humanoid shape is much needed here, as it will reduce the fighting of the people getting taken care of against being 'handled by a machine'.

These robots could serve as some kind of "reserve pool", if they have a similar set of capabilities than the military robots, just needing a different set of commands and the toys of a soldier.

  • $\begingroup$ A humanoid shape could actually have the opposite of the desired effect if it happens to cause the robot to land in the uncanney valley. If so, the humans might be disgusted by it. $\endgroup$
    – Cort Ammon
    Sep 18, 2016 at 0:27
  • $\begingroup$ This idea of "familiar face" for humanoid figures will eventually go obsolete. The level of complexity to get out of uncanny valley makes everything exceptionally expensive. We can get a "better connection" with something non-human, like Wall-E or Wheatley (from the Portal game). $\endgroup$ Sep 18, 2016 at 9:02
  • $\begingroup$ "The world is made for humans" point is the most convincing IMO - the fact is that if you want a bot that can do everything a human soldier can do - it needs to be human shaped, or else it'll eventually run into a task that a human can do that it can't. Quadcopters and wheeled bots are great and all until you need to get through a closed door (without blowing it open), drive a "dumb" car, or operate power tools and weapons designed for humans $\endgroup$
    – Bitsplease
    Aug 10, 2021 at 20:36

I can think of one reason. If your infantry makes use of powered exoskeletons, someone is likely to think 'wait, do we need to have the human in there all the time?'. It could start with exoskeletons or powered armor capable of autonomous use, with specialized autonomous variants being developed from that.

You'd have some perks like them potentially being able to use a variety of tools, vehicles and weapons, but the main reason you'd be doing it is you already have an assembly line putting out what are in essence humanoid robots.


Firstly, humanoid robots are considerably more expensive than simpler, more narrowly purposed devices, such as you suggest with drones. The trade-offs for upright gait make evolutionary sense - saving calories while walking in order to reserve those calories for higher consciousness - but not robotic sense.

Slithering for example is much simpler; a few parts repeated, attached together, simple algorithm, done deal. Helicopter (quad/hex et al) drones seem to be the sweet spot for utility vs versatility at short range, i.e. hovering, vertical take-off and landing and quick reorientation and maneuverability - vis a vis dragonflies, such that they have survived millions of years.

With humans/humanoids the entire equation is different. We evolved large brains and in short order, on evolutionary time scales, have placed ourselves on a path for opting to rid ourselves of our cumbersome, but narrowly advantageous, calorie conserving frames, to go further into the mental spaces, augmenting our brains, storing them, understanding them better. The laughable thing to me is that brains seemed to have evolve for the very purpose of becoming bigger brains.

Secondly, mechs are even more complicated and expensive that humanoid robots because they not only have to emulate what a humanoid robot can do, but then they must incorporate a user interface into the equation so that using them is not an uncontrollable affair. The bounding and the jostling and the controlling of the mech must be such that the whole system behaves in a way that is natural to human movement. Otherwise, by requiring the user to work harder than they otherwise would than by simply being deployed on foot, then the proposition becomes too risky, i.e. it equates to throwing a poorly functioning and very expensive piece of equipment and a highly trained soldier along with that expense into a situation where positive results are less likely.

So no, in a combat situation, I would say that terminators and other humanoid robots, including mechs are pure fantasy.


To clarify the distinction between mechs and augmentative devices such as the exoskelton. A Mech is a fully armored and equipped combat device where as the primary focus of exoskeleton devices is for aiding in ground deployment, e.g. such as helping to carry equipment. Other options such as mechanical mules are included as alternatives to the exoskeleton.

The maneuverability and agility necessary in full engagement are the issues which limit the practicability of mechs and increase the requirements and complications for making them feasible.

  • 1
    $\begingroup$ "pure fantasy", +1. Why weren't all the attack droids in those new movies like the Q-series ones (the rolling 'destroyer droid' type)? My guess is that people like to watch movies about people, not droids that could take over the universe... and that's why there was only two of them, otherwise what's to stop them? Non-infiltrating humanoid combat robots are stupid ;) $\endgroup$
    – Mazura
    Sep 18, 2016 at 2:23
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    $\begingroup$ @Mazura Agreed. Human-centric perspectives are quite narrow but unfortunately without them stories for humans seem to lack grounding and familiar principles and therefore do not sell. Non-human perspectives are difficult for us to frame and identify with, but perhaps that's the point in works that have attempted to explore without them. Maybe one day we'll have virtual spaces with good sensory feedback in which to explore non-human senses, thoughts and processes. $\endgroup$
    – Nolo
    Sep 18, 2016 at 4:04
  • $\begingroup$ The whole point of terminators was infiltration - which seems to have been forgotten about. Otherwise in the first film's future scenes you don't see them in the exoskeletal form on the front lines like the second. Of course the rule of cool applied there. $\endgroup$
    – cyborg
    Dec 22, 2020 at 2:19

As you wrote, specialized robots like drones, autonomous tanks etc. are superiour in almost every way.

However, I could think of two reasons why a military force might use humanoid robots:

  • These robots could use existing tools and vehicles made for humans. If they are smart enough, they could just get into any car, tank or helicopter and use them for their mission.
  • To hide the fact that they are robots. They could fore example move through enemy cities as spies. If they get caught, you could just turn them off without any ethical debates and also without blackmailing attempts.
  • $\begingroup$ Another reason is that legs are good for navigating rough terrain that wheels/tracks can't handle and hands are excellent for manipulating things. Why not at least start with a proven design? $\endgroup$ Sep 17, 2016 at 8:52
  • $\begingroup$ I particularly like the second one, +1 $\endgroup$
    – TrEs-2b
    Sep 17, 2016 at 8:57
  • $\begingroup$ Agree, the second point is probably the best. Hiding robots inside human population is a great idea. In David Wingrove's "Zhong Guo" saga, some bad guys are doing that, they are creatings robot clones of important people, and are using these as kamikaze. $\endgroup$
    – Kaël
    Sep 17, 2016 at 10:23

I think such combat robots might be usefull. Let's consider why.

Firstly, today we're using flying combat drones that are really effecient to supplant conventional aircrafts. They can sustain much higher speed, because you don't have to care about a human suffering from g forces inside your drone. Nonetheless, even if they're pretty efficient they have the same problem all aircrafts got. When you're fighting in higly dense area, like forests, mountains, towns, these sort of drones tends to be less adapted.

Secondly, you might think then "Eyh let's use flying drones with propellers, these would act like helicopters and works perfectly". Helicopters are far more adapted to urban environment for sure. Nonetheless that's the kind of hard to maintain equipement, I can't find my source anymore but I read somewhere on world building SE that helicopters had a ton of drawbacks preventing armies from having hundreds of thousands of these instead of using trucks. On top of that, even with no drawbacks, you're not going to fight inside buildings with such drones. And you definitely can't do it either in forests.

So then another solution is using drones with wheels/tracks or perhaps many legs, but not humanoid shaped with two legs and two arms. Wheels and tracks ? Not adapted to difficult terrains too. Many legs ? Means more cost, will be more stable and more efficient than two legs robots. At least, robots with legs would have that advantages animals and humans got to move on almost every kind of terrain.

But then why giving arms/heads/eveyrthing that defines a human shape to a robot ? Well perhaps for military it's no use at first, in combat situation a robot do not need arms, it can have turret mounted weapons most likely and accessories to supplant arms, it does not need a head either, or not the same one we human got. But outside of fighting ? Don't your drones have any other goal than just to fight ? A soldier does not fight each second of his life. He need to do things that could require arms, like building stuff (fortifications most likely), or transporting supplies, or doing some maintenance tasks, even help the civilians (don't forget today's armies are often used to provide assistance to civilians in case of natural disaster)s.

Last point for me would be : Civilian use and war economy. If the army is producing drones for it's own purposes, it is very likely the civilian industry will produce drones to. If they are enough advanced, people would really like to have a robot with which they can talk and live. And I guess everyone likes more to live with something that mimics living beings (so cats or dogs, or even human-shaped robots) than with weirds robots looking like a tank.

Would you like to talk to a tank in your dinning room ? If yes, then you're really hardcore sir ! But anyway this is not the point.

If drones are produced by the civilian economy, esthetics factors (like humanoid shaped robots) needs to be taken into account for customers, thus having humanoid like robots makes sense. And when war will break out, all the robots produced by the civilian industry would make perfect second hand drones to use as military stuff. They'll just need to be refitted a little, like adding a new shape with a bit of armor, creating some programms to teach them how to fire, and give them small fire arms and here you are, cheap robots fighters coming from the civilian industry without any need to heavily convert your civilian factories into military factories. Easy isn't it ? Even easier than converting cars factories into tank factories.

It would most likely give a great advantage in the case of a total war, to have at once a full stock of ready-to-be-converted robots. The best is, before any war breaks, the country using such method would be considered pretty weak "Eyh look at them they have such a small army, they are no threat to us." And then the war breaks, and millions of civilians robots are turned into fellow fearless soldiers, ready to fight for the mother/father - land.


Humanoid robots for military use would have several advantages:

As humans sized and shaped robots, they are already the right shape to interact with the "human" environment. Humanoid robots will be able to open doors, drive cars off the road, pick up and manipulate tools and other objects in the local environment because they will be able to do what every person can do. Specialist combat robots will be able to fight in their environments and use their weapons, sensors and tools far more effectively, but in the chaotic environment of urban combat, a general purpose machine might be more useful. A "gunship" robot might have to expend ammunition shooting through doors or blasting a stalled car off the road when such actions are not necessary or even counter productive.

Human shaped robots might be able to interact with the local population more effectively as well. While the idea of dealing with mechanical men might be strange or even abhorrent to the local population, they are still programmed to respond to and interact with humans. A human robot who makes a friendly wave, or holds out a cell phone for the person to take and talk to a "real" human on the other end is much easier to respond to than an anonymous box with a remote weapons mount and a manipulator arm that rolls up to you on a set of tracks.

Human robots will also be a strong signal of intent. It won't take long for the local population to realize that we send robots into high danger areas ahead of human troops, with the expectation they can take fire without taking casualties, and using their robotic sensors and weapons, respond faster and far more accurately than any human. One could imagine a robot soldier responding to an attack by an enemy squad. Outside observers hear an irregular burst of fire and find all the enemy soldiers dead with a single gunshot wound. The robot aims and fires so fast that the observer hears what sounds like a burst of automatic fire, but the robot is actually taking single aimed shots at each target.

After a few of these encounters, the appearance of robot soldiers will cause the local population to either hide, or expel the insurgents hiding in their midst. (A negative possibility is they decide to come out and fight, but this would require a very strong indoctrination of the local population, on the level of the Imperial Japanese government preparing the civilian population to fight the Allied invasion of the Home Islands with bamboo spears!).

The technical demands of creating a humanoid robot for combat are very high, so many of the tasks of combat will be devolved to specialist robots. IT is much more likely there will be a human solder in the field, but surrounded by robotic devices to assist and protect him instead.


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