I. Introduction
Robotic assistance in minimally invasive surgery (MIS) extended the capabilities of surgeons via improved precision, dexterity, and computer assistance [1], [2]. Recently, novel single port access surgery (SPAS) and natural orifice transluminal endoscopic surgery (NOTES) have been investigated by the authors in [3]–[6] for their potential benefits in reducing patient trauma and shortening their recovery time compared to traditional multiport laparoscopic MIS. However, SPAS and NOTES also set strict requirements for instrument miniaturization, dexterity, and collision avoidance between surgical tools operating in confined spaces. Existing surgical robots for MIS cannot satisfy these requirements due to either dexterity deficiency or the size of their actuation mechanisms that prohibit a multitude of arms from operating through a single port. Therefore, to date, SPAS is still limited to a small number of academic centers using instruments that are not clinically proven to be able to facilitate SPAS [7]–[9].