What are Issues of Transforming Robots or Robots that Combine into Bigger Mechs?

[The Colonel]

Originally Posted by johndallman

There are folding bicycles, of several kinds. It inevitably adds weight and cost, but the advantages are worthwhile for people who need to make part of their commute on public transport.

And Klepper are famous for their folding kayaks. Apparently very popular with "Them".

[Anthony]

In general, making something collapsible means adding structural weight and/or losing structural strength, and requires the in-use shape of the object to have an inconvenient shape or be annoyingly bulky. Humanoid mechs probably aren't awkward enough for that to be worth the effort, putting a mech in a box will have some waste space but not enormous amounts.

Making something transform usually also means that it's got inactive components that are waste mass in one of its modes -- for example, a vehicle that transforms into a humanoid will have a useless wheeled drivetrain while in mech mode and a useless walking drivetrain while in vehicle mode. Much of the time, it's more efficient to store those temporarily unused components somewhere else while not in use -- i.e. you put the mech on a truck to move it about.

Another thing to consider is detachable components. The simplest is just something that can be disassembled for transport or storage, but you could also have something like a mech that detaches its legs, attaches itself to a truckbed, puts the legs in the cargo area of the truck, and drives off (this is some savings over a straight-up truck, because the mech's power plant and controls are used to control the truck, rather than the truck having its own).

[whswhs]

Originally Posted by Anthony

Another thing to consider is detachable components. The simplest is just something that can be disassembled for transport or storage, but you could also have something like a mech that detaches its legs, attaches itself to a truckbed, puts the legs in the cargo area of the truck, and drives off (this is some savings over a straight-up truck, because the mech's power plant and controls are used to control the truck, rather than the truck having its own).

In a sense, the robot that's assembled out of smaller mecha is a cinematic version of this idea.

[Anthony]

Originally Posted by whswhs

In a sense, the robot that's assembled out of smaller mecha is a cinematic version of this idea.

Except the smaller mecha each include a bunch of systems that aren't useful to the combined version; most detachable component systems include a bunch of components that are unusable when detached.

[Flyndaran]

Originally Posted by jeff_wilson

A somewhat humanoid, transformable robot may be feasible and useful for some circumstances, like bomb disposal bots that can approach the IED in protected vehicle form, then unfold to do the manual work. AFVs may have one or more arms that can deploy to clear debris, open and close gates, or maintain treads.

Also some designs that already incorporate "wasted" space might be good transformer candidates, like an exoskeleton that can roll around when empty, Metroid Prime-style.

I now picture cheap fast food type transformers with limited humanoid shapes rather than sleek official Transformers/Gobots styles.
As in vehicles that simply pop out fragile manipulators and sensors without ever really looking like an android.

[Flyndaran]

Originally Posted by Anthony

...
Another thing to consider is detachable components. The simplest is just something that can be disassembled for transport or storage, but you could also have something like a mech that detaches its legs, attaches itself to a truckbed, puts the legs in the cargo area of the truck, and drives off (this is some savings over a straight-up truck, because the mech's power plant and controls are used to control the truck, rather than the truck having its own).

I know, a long time ago, I saw a sci fi movie with a cyborg that did just that.

I really want to create some kind of world jumping scenario where such a character would make sense.

[Flyndaran]

Originally Posted by whswhs

In a sense, the robot that's assembled out of smaller mecha is a cinematic version of this idea.

Maxwell's mecha? (goofy smirk)

Though with the buzz word nanites, robots like the T1000 count as the ultimate version.

[Phoenix_Dragon]

Originally Posted by Johnny1A.2

It occurs to me that a 'collapsible' car, plane, boat, or whatever, could have its uses. That is, a vehicle that could be collapsed down into a much smaller volume for storage, then restored to its initial form. Difficult from an engineering POV but possibly handy for certain purposes.

We do have that, to a degree, with carrier aircraft. The Osprey is particularly impressive.

[Anthony]

Originally Posted by Flyndaran

I really want to create some kind of world jumping scenario where such a character would make sense.

It implies that some shared component (likely the power plant) is exceptionally expensive, so it's worth the effort to move it around instead of just having two.

[Bruno]

I've never bought the "With a neural interface it has to be human shaped or humans can't pilot it" argument.
Vehicular controls, and even more so, computer controls for video games, have beautifully demonstrated the human ability of extension of prioperception to inanimate object, to our clothing, our tools, and even to vehicles.
Nobody says "Today another driver's car hit my car while I was driving my car on the freeway." They say "That jackass hit me while I was on the freeway!" The other person is made synonymous with their vehicle, and you are synonymous with your vehicle. Your sense of personal space expands to be the size and shape of your car (not humanoid at all), giving you a good sense of where all the edges of your vehicle are to help with collision avoidance.

At the other end of the scale, quadriplegics who can do nothing but move their eyes and regulate their breathing to blow or suck on a straw perform the same magic trick with an electric wheelchair, with videogame characters, and these days even with drones and other remote controlled small vehicles.

People playing videogames can inject themselves so heavily into the experience that they lose peripheral vision, and have a good intuitive sense of motion and control in the world, even though all they get to do is punch buttons and wiggle a stick on a game-pad, and even though the physics in the world are inevitably inaccurate (often grossly inaccurate). Your entire lifetime of experience with how friction and gravity work can get thrown right out the window with a videogame, but people adapt very very quickly.

If anything, the "not quite right" of motion controls throws people off significantly more. Your entire body knows that you don't move forward by stomping on the ground in front of you, but it's enough like the real motion that it can really mess you up. Bad motion controls are like the Uncanny Valley of interfaces.

I can only imagine having to pilot something that is utterly unlike the human body in its actual properties by using our (definitely learned) abilities to control real human bodies is going to be like bad motion controls.

If fighter pilots and race car drivers can make do without flapping their arms or paddling their feet, I think someone with a direct neural interface can do just fine.