AI Panel

This panel is used to tell the screensaver how to "pilot" the ship. In fact, you are basically defining the ship's pilot here. Note that this is becoming more and more depreciated, with the pilot prefering to fly the ship to the ship's capability. (See Controls Panel.) This panel isn't full depreciated yet and the settings still have a small effect.
Control Preferences
Percentages are used to set what kind of maneuvers a ship's pilot prefers. If you don't want the pilot to roll very often, set the Roll percentage low. If you want the pilot to Yaw like crazy, set it high. These numbers don't have to add up to one or anything. They are independent of each other. You are telling the screensaver how often the pilot will attempt that maneuver.
Standard and No AI
Standard AI consists of a pilot, flying a ship. No AI, on the other hand, is basically telling the screensaver engine that this ship has no pilot, for ships like asteroids. This only affects the ship's movement. Turrets are manned with their own personnel and are not affected by this setting, in cases like space stations with no mobility, but bristling with weaponry.
Large and Small Ship Forces
Setting either of these options will override how the screensaver looks at a ship. The screensaver tends to look at small ships (in relation to other ships in the scenario) as small and larger as large. If you have a scenario where you are fighting Star Destroyers against the Death Star (and you have a monster of a processor!), the screensaver will look at the Star Destroyers as small ships, because they are comparatively. Obviously, Star Destroyers *aren't* small ships though.
The screensaver gives certain attributes to ships, depending on what size it perceives them to be. Small ships tend to use spheres around them for other ships to detect in collision avoidance. Large ships, on the other hand, use a model closer to their actual model. It wouldn't make sense to have a large sphere around a Star Destroyer being used for collision avoidance - you'd never strafe the bridge! The sphere detection is faster with small ships, while the model detection works better for large ones. Large ship models also inherit spectacular, and I mean *spectacular*, warp core nuclear explosions when they are destroyed.
Another case where you might want to override the type, even though in the screensaver the size is correct, might include a dense asteroid field of large asteroids. Overriding the asteroids as small, even though they're not, will increase the overall speed of the screensaver, enabling it to use quick spherical collision avoidance checks instead of the detailed model ones. Fighters would tend to try to keep more distance from the asteroids, unless of course they're agressively chasing someone.
Camera Can Focus
Setting the Camera can focus on this object option lets the screensaver know that this is an interesting object. Any object or ship that has this setting disabled will be considered uninteresting and will never be the center of the screensaver's view.
Perception
The perception range specifys how far out around the ship the pilot remains aware of other ships and objects. Ships beyond this range are not seen by the pilot. To be truly realistic, you can enable Asymmetric perception. Here you can specify the ranges of the pilot's awareness in each of the six planes of a cube. This can create some really interesting battles with ships on each other's "sixes" with the targetted ship being unaware of the ship behind it. You can easily figure out how to set these values by imagining yourself sitting inside the ship's cockpit. Any direction where it would be hard to see should have a low value.