Mechanical design and control system of a robot assisting Photodynamic Therapy for Port Wine Stains

Port Wine Stain (PWS) birthmarks are congenital vascular malformations, which usually appear at birthand tend to become darker and thicker with age. Vascular-targeted Photodynamic Therapy (PDT) is an effective approach among treatments for PWS. However, due to the arbitrariness of manual operation and pole points in laser radiation, the PWS zone was always cured unevenly in clinics. This paper presents a novel robotic system, which consists of a passive arm and an active wrist to assist doctors to exert PDT treatments. This paper, firstly, introduced the mechanism of PWS and its treatments. Based on the prosperities of PDT, we designed the robotic system architecture, which consists of the medical robot, binocular vision and workstation. Then the detailed mechanical design on the robot with combined passive and active joints was given. Furthermore, we discussed its control system, which is key and direct factor for PDT. To validate the robotic system, we have done some experiments to assess the accuracy of the active wrist and whole robotic system. Experimental results showed that the robotic system could reduce much more work burden and realize more uniform radiation than manual work could.