Consider your hand. You control all those 27 bones through muscles and tendons. The nerves give you feedback and send your commands down the like, commands that you are not even conscious of. Twist your hand, and you see it twisting. The large muscles come through the skin, but all the fine motion is lost unless we specifically look for it. It can grab and hold things in a wide variety of positions and ways, some that we don’t even know before someone else teaches that. These hands can build and destroy in equal amounts, they are our the tools of our creations.
Transferring that to a giant robot is a bit of a hassle.
Much like with a lot of other direct transfer elements with human body and giant robots, adapting hands 1:1 is an easy concept for sure. The idea of similar multi-use manipulator is attractive from the get go, but depending on the setting, human-like hands might not be the best option. A human-like hand requires far more parts, development, maintenance and simple tech than a say a pincer or more simple manipulator. Of course, the main argument for having a hand for a giant robot is its versatility, especially when it comes to weapons. However, that’s something that could be easily done with hardpoints where weapon is being mounted. We should also question how versatile does the hand of a giant mecha be, especially for a war machine.
Broadly speaking, all human-like hands with mecha follow the same basic idea, there isn’t much deviation. It’s either smooth or cubic. Using this example from a VF-19 serves as a good showcase.
While it looks complex, it’s more about the layered elements that make it look complex. Inner functions are of course barely thought, they’re not important. The fact that it looks like it could work and has plausible design elements, like the knuckle guard and fingers’ segments layer on top of each other when bent, is more than enough. Studio Nue has always preferred rounder elements to their design (sometimes dubbed as Bubble hands), especially with their older works. In Gundam, Sunrise and Bandai have preferred using more cubic hands, although exceptions are aplenty.
The above generic Mobile Suit manipulator was designed for the models, but seeing how Bandai and Sunrise design their mechas models in mind nowadays, it’s a good example of a hand that’s more or less designed for wielding a gun and a beam sabre. It’s a bit more straightforward than VF-19’s, less well-rounded. The question of course is, if this hand is largely made for weapon carrying, why isn’t it designed as such?
The answer is, of course, because of Rule of Cool. When mechas are designed as characters, they’ve almost always given large amount of human characteristics in order to showcase dramatic events. Hands are no different in this. Beam sabre battles would be less dramatic and interesting if the manipulator would be specifically designed holder than a hand.
Controlling a hand like this has basically three options, direct 1:1 input, control macros or brain wave input. Variations and combinations do apply. While a “glove controller” would be idea, that’s pretty much what you do then with that arm. It’ dedicated for that arm, and the rest of the controls are either automatic or left other arm or legs. We discussed control macros previously, and this is most likely the best option overall, if brain wave scanning tech is not available in your setting.
Designing mecha’s hand really isn’t anything hard; just look at your own and mechanise it. Give it details for something to grab attention and some panels for easy access.
Giant robots don’t really have a need for similar level of sophistication when it comes to their hands, a simple grasping arm should be enough with some level of modification to suit the needed purpose. Hardpoints add a lot of versatility as well.
Of course, fiction doesn’t need to play by the rules of reality all that much, and if technology is advanced enough in a fiction to produce these things, why not? They could of course build better and simpler manipulators, but sometimes you do seek more complex solution for the sake of all the options it could give you. A gripping manipulator above doesn’t really offer many ways to grasp a thing.
Some franchises mix human-like hands with specifically designed manipulators, Muv-Luv popping to my mind foremost.
Another one would Mobile Suit Z Gundam‘s The O with its assisting manipulators underneath its skirt. These manipulators question why would The O even need human-like hands, when the three-prong manipulator does everything they do. The answer to this is, of course, because the human design does not use that sort of hand. In a way, mecha in general should always be contrasted to armoured knights of legends, but that’s another topic.
Hands are ultimately something that Japanese inspired mecha design does. For giant robots, America has always preferred more built-in options. MegaBot’s Mark II is a good example of this.
American vision usually attached the weaponry onto a pre-fixed arm that may have some freedom of motion to it, but is always more dependent on the movements of the main body. Compare this to Suidobashi Heavy Industry’s Kuratas and the difference in approach is notable.
The idea of having this built-in approach and lack of manipulators is just as valid. While it lessens on-the-fly options and puts some limitations, it eliminates loads of moving parts that would require maintenance. The most prominent film example of this sort of thing would be our good old friend, ED-209.
Unlike with mechas with arms and manipulators, you can see ED-209 guns are its arms with no manipulators, as it needs none. It’s a robust little connector that looks sturdy and serves only to take the beating from the cannon’s recoil and swivel enough to shoot whoever full of holes.
Keep an eye to hands you see in mecha films and shows. Take notice how they are portrayed and how they function. Rarely you will see them doing things outside the capabilities of human hands, and showcasing how they are actually controlled is even rarer. Sometimes they take advantage of what a machine hand can do, like how ∀ Gundam washes clothes by rotating its wrist 360-degrees in repetition.