Irregular Incurve is a MIDI controllable robotic string instrument. The twelve independent string-units compose the complete musical scale of 12 units. Each string can be plucked by a motor control guitar pick. A MIDI keyboard is attached to the instrument and serves as an interface for real-time interactions between the instrument and the audience. Irregular Incurve can also play preprogrammed music by itself. This paper presents the design concept and the technical solutions to realizing the functionality of Irregular Incurve. The future features are also discussed.