Morpheus: A Neural-driven Animatronic Face with Hybrid Actuation and Diverse Emotion Control

Blue markers indicate the attachment points between the underlying mechanical structure and the soft skin, while yellow arrows denote the directions of movement. Blue arrows indicate the three-axis neck movement: nodding, shaking, and rotation. The green arrow illustrates the jaw's ability for horizontal movement in addition to typical opening and closing motions, enabling more diverse expressions. The first row illustrates the virtual expressions generated by our algorithm rendered in Blender, while the second row displays the corresponding real-world expressions reproduced by the animatronic face. Abstract --Previous animatronic faces struggle to express emotions effectively due to hardware and software limitations. On the hardware side, earlier approaches either use rigid-driven mechanisms, which provide precise control but are difficult to design within constrained spaces, or tendon-driven mechanisms, which are more space-efficient but challenging to control. In contrast, we propose a hybrid actuation approach that combines the best of both worlds. The eyes and mouth--key areas for emotional expression--are controlled using rigid mechanisms for precise movement, while the nose and cheek, which convey subtle facial microexpressions, are driven by strings. This design allows us to build a compact yet versatile hardware platform capable of expressing a wide range of emotions. On the algorithmic side, our method introduces a self-modeling network that maps motor actions to facial landmarks, allowing us to automatically establish the relationship between blendshape coefficients for different facial expressions and the corresponding motor control signals through gradient backpropagation. We then train a neural network to map speech input to corresponding blendshape controls. With our method, we can generate distinct emotional expressions such as happiness, fear, disgust, and anger, from any given sentence, each with nuanced, emotion-specific control signals--a feature that has not been demonstrated in earlier systems.