This paper presents part of an on-going project to design a wearable supportive device to enhance facial expressiveness, in particular for the facial paralyzed patients. Earlier we introduced the SMA actuator based Robot Mask that can be used to enhance the expressiveness of the face. The basic concept of that design was pulling of the skin through wires attached to the face and we explained the human anatomy based criteria of selecting these pulling points and directions. The major reason to use SMA instead of traditional actuators such as motors was their silent acting nature. However, their dynamic properties been governed by thermal energy and their mechanical properties been affected by the hysteresis due to their metallurgy, SMA based actuators tend not to perform too well under cooling. This paper introduces a novel controlling scenario that use the actuation of only a limited number of SMA wires out of the total connected in series on either sides of a slider to control the direction and amount of movement of the slider. The advantage of this method is by keeping some SMA wires at low temperatures it was possible to achieve a high speed of actuation even when the direction of motion was changed. This paper also investigates on the amount of actuation rates that are required to generate natural looking smiles and later attempts to recreate them using the proposed actuation unit.

This paper presents part of an on-going project to design a wearable supportive device, in particular for the facial paralyzed patients to enhance facial expressiveness. As various complications can result in facial disfigurement and loss of functionality in facial muscles it is required to develop a supporting device for people with such conditions. The previously proposed robot mask, which consists of a head supporter and motor units attempts to recreate facial expressions artificially by pulling the facial skin through cables attached to the skin. Since a facial expression is the result of the full or partial activation of combination of facial muscles, it is necessary to control the amount of displacement of the artificially created skin movement. Furthermore, in order to facilitate interpersonal timing of facial expressions, it is necessary to be able to read the nerve signals and process them in real time. This paper presents a compact and fully controllable actuation unit for the earlier proposed robot mask, and analyzes the relationship between the displacement of the specifically selected areas of the face and the actuation by control unit. It also present a bioelectrical signal based real time signal processing system to determine the requirement for an artificial expression.