Integration of Force Feedback in an Open Robot Platform for Robotic Surgery

We present an open robot platform for minimally invasive surgery capable of very sensitive force feedback, which has been developed in very close cooperation with surgeons from cardiac surgery. Forces are measured at the surgical instruments and fed back into the surgeon’s hands using multi-dimensional haptic styluses. Integration of force feedback with stereo vision, as offered by the system, will improve accuracy, drastically reduce the time needed for operations and tissue trauma, along with a reduction of stress on the surgeon. This could lead to a wider acceptance of robotic surgery by both, patients and surgeons. The system’s software interface and mechanical set-up descriptions are freely available to enable other research groups to participate in the development. Introduction During the last decade minimally invasive surgery has become the leading method for many surgical interventions. Unlike open surgery, minimally invasive surgery only needs small incisions in the patient’s body. This leads to a drastic reduction of tissue trauma and therefore to shorter recovery times. In the beginning this technique was performed manually with specialised instruments. Today, dedicated robotic systems are applied to assist the surgeon. Commercially available systems like the daVinci workstation [1] provides a decoupling of input device and instruments. The surgeon controls the instruments with a master console that is placed separately in the operating room. The instructions are carried out by a tele-manipulator, whose end-effectors perform the operations. This allows for comfortable work and full 6 degree-of-freedom (DOF) control of the instruments. Additionally, vision of the surgeon is improved by means of endoscopic stereo cameras, whose images are displayed at the surgeon’s console. This system has a proven record, and many delicate operations have been performed [2..5]. A number of similar systems, both in research and for commercial use have been developed. These include, for example, a robotic system developed at UC Berkeley, which has already been used to perform certain surgical tasks like suturing and knot-tying [6]. The Korean Advanced Institute of Science and Technology has developed a micro-telerobot system that provides force feedback [7]. In Germany the first systems for robotic surgery was built at the Research Facility in Karlsruhe [8] and DLR [9]. While the former system provides no force feedback, the DLR system is equipped with PHANToMTM devices for haptic display. Despite the advantages the systems offer, there are also needs of surgeons that have not been met. The most crucial issue is the lack of sensitive force feedback combined with delicate and fine instruments [10..12]. This often leads to unpleasant side effects like damaging thread material or even lacerating healthy tissue. It is in particular this shortcoming that results in a fast exhaustion of the operator, because the missing haptic feedback has to be compensated for visually.