US Patent 10310608 Wearable accessory for force feedback

A wearable actuation device allows a user to interact with virtual objects in an AR or VR environment by providing force or haptic feedback. The wearable actuation device includes one or more actuator assemblies anchored to each of the user's fingers and a controller configured to communicate with a head mounted display. Embodiments of the actuator assembly include an electrorheological actuator, an optically driven actuator, and a piezo actuator sandwich assembly each of which is configured to undergo a reversible change in stiffness in response to an applied voltage or current. In one or more embodiments, the actuator assembly is configured to stiffen, elongate, compress in response to the application of a current or voltage waveform. In still other embodiments, the actuator assembly determines a measures of the current stress or strain being applied by the user on the virtual object.