Below are some thoughts about creating a layer of “character behavior” for robotic performance.

• “Action Model” / usually a pre-planned sequence of actions
• ““Behavior Model” / rules for generating characteristic behavior

If the behavior is being expressed in movement (e.g. a wheeled robot moving on a stage), then it might have basic parameters like this:

Direction
Purpose or seeking (straight) vs. confusion (e.g. spinning) …

Distance
Longer distances would indicate greater divorce from reality, schizophrenia …

Duration
Short quick movement would indicate nervousness; longer might be thoughtful …

Interval
Shorter time between movements would indicate greater self-involvement or agitation …

Intensity
A fudge factor to scale up or down the other parameters, particular distance, duration, and interval …

Other thoughts:

Other interactions with the action model are possible. For example, a character might switch from one behavior model to another under control of the action sequence.

Even more interesting, the action sequence could control the intensity of the behavior. If the behavior intensity increased as the character approached an obvious goal or interaction with another character, for example, they would seem relatively sane and responsive … “rising to the challenge”. If the behavior got MORE intense as the challenge rises, the character would seem highly neurotic or paranoid.

Ultimately, the aesthetic effect of these behaviors should be determined empirically … try it on a specific robot, then log it into a database that could be used to select character qualities by the director.