Hydraulic actuation in miniature medical robots

摘要

To reduce the trauma to the patient, minimally invasive surgery is gaining importance since the eighties. At present, several minimally invasive therapies (MIS) have replaced conventional surgical procedures. However, existing MIS methods including robot-assisted methods reduce the positioning capabilities of the surgeon. Existing robotic assisted systems consist of a slave and a master side (figure 1). At the master side, the surgeon controls the position of the instruments. At the slave side, a robotic manipulator actuates the instrument. Current manipulators are based on conventional minimally invasive instruments. The instruments are placed at the end of long tubes that are inserted through trocars into the body. Four degrees of freedom are controlled at the outside and advanced systems have two additional degrees of freedom at the instrument tip by a cable transmission. To give the surgeon the possibility to operate within a larger volume without trocar replacement, to allow him or her work behind organs and to increase the number of possible operations, instruments with more degrees of freedom inside the human body need to be developed. To achieve this small, actuators with a high force and power density are required.