A Haptic Interface Design for Minimally Invasive Telesurgical Training and Collaboration in the presence of Time Delay Shahin S. Nudehi and Ranjan Mukherjee Moji Ghodoussi Department of Mechanical Engineering Computer Motion Michigan State University 130-B Cremona Drive East Lansing, MI 48824 Santa Barbara, CA 93117 Abstract In this paper we propose a “shared-control” archi- tecture for design of a haptic interface for hands-on training in minimally invasive surgery. The inter- face is designed to allow an experienced surgeon men- tor a trainee surgeon from a distant location through share-control of a robot performing a surgical proce- dure. During share-control, the haptic interface pro- vides feedback forces to the surgeons proportional to the diffference in their actions and the control author- ity shared by them. The control authority of the indi- vidual surgeons is chosen based on their relative level of experience and can be changed at any time. In this paper we use robust control methods to design stabilizing controllers for the haptic interface assum- ing time delay in transmission of signals between the surgeons. We use both simulation and experimental results to demonstrate stability of the haptic interface and its suitability for the intended application. 1 Introduction Although minimally invasive surgery has gained widespread acceptance due to the significant advan- tages realized by the patient in the form of reduced trauma, recovery time, and total procedural costs, growth in the number of minimally invasive surgical procedures has stagnated. The stagnation can be at- tributed to the fact that most surgeons routinely use minimal invasion to perform simple procedures such as cholecystectomy and appendectomy, but are deterred from performing the more complex procedures. A ma- jor factor leading to this problem is the lack of ade- quate training and mentoring facilities that enable sur- geons gain proficiency through hands-on experience. The typical method in which a surgeon learns a new procedure is by attending a training course first, sec- ond by visiting another surgeon to watch the new pro- cedure, next inviting a mentoring surgeon to guide him perform his initial operations, and finally perform the operations on his own. This mode of training, which is based on the ancient surgical doctrine of “see one, do one, teach one” by Halstead, is time-consuming and inefficient. Depending on the initial experience of the surgeon and complexity of the new procedure, the effort necessary to learn the new procedure may range from a few days to several months. Oftentimes a surgeon will pursue a new procedure by attending a training class, but never complete the process required to adopt the procedure because of time and financial constraints. It is well documented that the adoption rate of new advanced MIS procedures among surgeons who attend training sessions is only around 10%. A number of researchers have proposed virtual reality models for improving surgical training and education [1], [2], [3], [4], but hands-on experience can only be imparted through the development of a haptic inter- face that provides force feedback proportional to error in action during surgery. In the literature, haptic interfaces have been pro- posed for many useful applications such as surgical training [5] and robotic tele-operation [6], [7], [8]. Some of the recent research in this area [9], [10], [11], [12], has focussed on stability of interaction with real and virtual environments under the assumption of passivity [13] of the human operator. To overcome the conservatism of the passivity formalism, some re- searchers have introduced the concept of uncondi- tional stability [14] from network theory [15], and pro- posed control design based on estimation of excess of passivity [16]. An important problem in many app- plications of haptic interface design is the presence of significant time delay in transmission of signals. While the general problem of stability of time-delay control systems has been addressed by many researchers, [17], [18], [19], [20], for example, the specific problem re- lated to haptic interfaces has been addressed only by a few. Niemeyer and Slotine [21] and Yokokohji, et Proceedings of the 42nd IEEE Conference on Decision and Control Maui, Hawaii USA, December 2003 ThP13-5 0-7803-7924-1/03/$17.00 ©2003 IEEE 4563