The Dismounted Soldier Problem

Pilchie asks: "When reading this recent article I started thinking about a problem I learned about when working for Canada's DCIEM in the simulation training technology sector. Most of you are probably familiar with some type of simulator or virtual reality. Have you ever noticed that every VR game includes some kind of vehicle? The reason is that no one has been able to develop a system to accurately simulate walking, without actually going anywhere. Before you laugh at this, think about it. How would you build a User Input system that allows a person to walk in an arbitrary direction at an arbitrary time?" Interesting thought. Anyone have potential solutions? (More below)

Pilchie continues:

"Some Ideas
These are some of the ideas that I have heard, and some of their drawbacks:

Don't walk. Use some other input system (joystick, whatever) to move the character. Problem: People get lost if they don't actually walk. See here.

2D mesh of bearings. This is probably the best idea so far, the idea is to have a 2d mesh of bearing that can rotate in any direction, each with a sensor to determine which direction it is rotating in. The drawback is the difficulty in sensing the rotation of the beads, as well as allowing them to move in any direction. Plus safety(things getting caught between the beads).

Spheres. This idea involves placing a person either inside or outside of a spere and letting the whole sphere rotate in an arbitrary direction (sort of like a mouse ball). The problem is making a sphere big enough, with little enough friction that it can actually be moved by a normal walking action.

Mime Walking. This involves teaching people to walk in a special manner to allow the system to know they are walking. See this again. Problem is that it is fake.

Large room/visual tricks. Put someone in a large room and let them walk where they want. When they start to approach a wall, rotate the picture enough that they compensate, but not enough that they realize it is rotating. Problem: obiously you can't be sure they won't hit a wall at some point.

Well what are your ideas on the issue?"

Comments

SQUID Sensors

[Crutcher]

There has been a lot of development in the squid field over the last few years (squids are a type of minute voltage detector), and while it takes a little training (ususaly about 10/15 minutes of practice to get navigable, which is much less than the time it took most of us to learn the nintindo controler) sqid based controlers have been under development for a few years. The idea is you only have to THINK about moving a muscle, and its voltage changes, but it dosn't actually move until you reach a treshold value. With this tech, there are all kinds of fun ways to solve the walking problem. Personaly, I would put squids in an input glove, and have it respond to *pushes*.
-Crutcher

Problem of acceleration

[rat]

As I see it the general problem here is the inner-ear based sense of acceleration. We feel it when walking, riding an elevator, falling, turning a corner in a car, etc. When the visual sense of place and the inner-ear sense of acceleration are in conflict, most people feel disoriented, sometimes to the point of nausea or vomiting.
In constant-speed walking, the acceleration perceived is largely up-down, except during the first and last steps. Perhaps an appartus with a wide range of movement could duplicate both the up-down acceleration (a simple matter of "bobbing") and the initial and final accelerations, each of which would be followed by a gradual (enough not to be noticed) acceleration in the opposite direction, to ensure an eventual return to center. My gut feeling estimate is that to be "believable" a machine of this design would have to have a diameter of about ten meters. Big and expensive, but perhaps doable.

rat

Re:dont laugh

[plunge]

Pretty funny, but not totally far from the best solution. We're actually reasonably close to being able to decifer nerve impulses, so controling walking via a tap into the spine isn't such a pipe dream. But there are some serious drawbacks regardless. 1) Pattern generators. Walking is a standard "program" the nervous system can "run", meaning it CAN do so without sensory input, and we can measure it. The problem is, PGs also use various sensory input to do "error correction," which means we could get all sorts of addative errors and confusing screwups. 2) Without actually walking, how are we going to make it "feel" like walking? Reproducing sensory feelings is way harder than measuring standardized spine output. It would feel extremely uncomfortable to "walk" without the proprioceptive feeling of walking. 3) Related problem- how are we going to shut down the muscles without shutting down the proprioceptive nerves in the muscles, which would also exacerbate the problems of 1 and 2