US Patent 9639158 Systems and methods for generating friction and vibrotactile effects

A system includes a sensor configured to sense an input received from a user at a surface; a first haptic output device configured to generate a first haptic effect at the surface based on the input received from the user, the first haptic effect comprising a friction effect at the surface; a second haptic output device configured to generate a second haptic effect, the second haptic effect comprising vibrotactile feedback; and a processor configured to receive an input signal from the sensor and output a first drive signal to the first haptic output device to generate the first haptic effect and to output a second drive signal to the second haptic output device to generate the second haptic effect.