In force feedback, the proportions and strengths of average joints must be considered. Since the hands are most often used for haptic interfaces, the properties of the hand should be considered when designing a new interface. In tactile feedback, the interface must track several variables of the human sense of touch. Also, the finger is sensitive to up to 10,000 Hz vibrations when sensing textures, and is most sensitive at approximately 230 Hz. Forces on individual fingers should be less than 30-50 N total.
Humans are very adept at determining if a force is real or simulated.
In an experiment conducted by Edin et al. The device consisted of a solenoid attached to a metal plate which was allowed to slide when the solenoid was turned off. None of the subjects were 'tricked' into believing that the object was actually slipping. There is a strong link between the two systems. Unlike the visual system, it is not only important what the sensory system detects, but what motions were used to gain that information.