2.2. Mechanical Design of the Prototype Robot

Figure 2 shows the proposed robotic system, which is divided into three parts: the robotic endoscope module, the robotic instrument module, and the master controller module. The robot was designed while considering its practical clinical use. First, the system was designed to be compatible with a conventional endoscope without modification. Thus, the healthcare facility can use an existing flexible endoscope and does not need to purchase an additional endoscope for the robot, which can be expensive; this design feature reduces the cost of the system.

Overview of the proposed robotic system for endoscopic submucosal dissection: (a) photograph of the complete system; (b) magnified view of the endoscope driving actuator unit; (c) magnified view of the coupling for the flexible part of the endoscope; (d) magnified view of the endoscope tip.

The system is equipped with two instruments: a grasper and an electrosurgical knife, and each instrument has a bending section at the tip. The maximum diameter of each instrument is 2.6 mm, which allows the instruments to be inserted into the instrument channels (φ: 2.8–3.2 mm) of a commercially available endoscope. This diameter is almost equivalent to the diameter (φ: 1.9–2.7 mm) of commercially available instruments that do not have bending sections.

The system was designed to be operated entirely from one console by a single operator. Conventional ESD is typically performed by one doctor and one assistant. If the robot required two clinicians (e.g., one operating the instruments and the other operating the endoscope), this would be costly. Furthermore, all four DOF of the endoscope can be controlled from the console: two dials controlling twisting and inserting the tip of the endoscope and two buttons to control insufflation and suction.