Design a combined active and passive robotic system for laser-based therapies

Port wine stain (PWS) birthmarks are congenital vascular malformations; they usually appear at birth and tend to become darker and thicker with age's growth. Vascular-targeted photodynamic therapy (PDT) is an effective approach among the treatment of PWS. However, due to the arbitrariness of manual operation and existence of pole points for laser radiation, the PWS zone was always cured unevenly in clinics. Thus, we developed a novel robotic system, which consists of passive arm and active wrist, to assist doctors in exerting PDT treatments. Passive joints are easy to interface with doctors, safe and convenience; active joints can automate the PDT, so that facilitate doctors focusing on clinical judgements and treatments rather than heavy manual work. In this paper, the mechanism of PWS and PDT were described briefly; the robotic system including the detailed robot mechanical design and kinematic analysis was discussed based on the requirements of PDT. Finally, the robot feasibility was validated by experimental results.