Cable-driven robots enable compact design by allowing actuators to be mounted away from joints. This kind of actuation is desired in surgical robots. The cables in these robots must remain under tension at all times in order to have optimum performance. Thus, the knowledge of initial value of cable tension is significant. Moreover, in surgery, haptic feedback is vital for diagnosis of healthy tissue and to prevent damaging tissue with excessive force. In this paper, cable pretension was estimated indirectly by estimating stiffness parameter of cables. Then, external forces acting on the robot were estimated in all four quadrants by using cable stretch and dynamic-based methods utilizing system dynamics and unscented Kalman filter (UKF). We assessed the effectiveness of these methods on the third link of Raven-II surgical robot platform. From experiments with the tension estimation technique, it can be determined if the cable pretension is in the safe range. Also, both the cable stretch and UKF-based methods can be used to estimate external forces on all quadrants.

Minimally Invasive Surgery (MIS) can reduce iatrogenic injury and decrease the possibility of surgical complications. This paper presents a novel flexible and bendable endoscopic device, “Roboscope”, which delivers two instruments, two miniature scanning fiber endoscopes, and a suction/irrigation port to the operation site through a single portal. Compared with existing bendable and steerable robotic surgical systems, Roboscope provides two bending degrees of freedom for its outer sheath and two insertion degrees of freedom, while simultaneously delivering two instruments and two endoscopes to the surgical site. Each bending axis and insertion freedom of Roboscope is independently controllable via an external actuation pack. Surgical tools can be changed without retracting the robot arm. This paper presents the design of the Roboscope mechanical system, electrical system, and control and software systems, design requirements and prototyping validation as well as analysis of Roboscope workspece.

This paper presents a novel system in which 3D graphics and high-fidelity haptic feedback can be generated seamlessly at the same physical location, without using mirrors or any other hardware other than a tool handle and the user's hand in the line of sight of the user. A thin flat screen is placed directly above an array of coils so that electromagnetic forces and torques can be generated through the display to act upon magnets inside the tool handle held by the user. An array of 16 coils generates forces and torques upon 3 magnets embedded in the tool handle. A detailed model of the forces and torques generated on a single magnet from the current through a single coil was calculated analytically. The coil currents required to generate desired haptic interaction forces and torques on the tool handle are calculated from this model at each control update using redundant control methods. Forces of several Newtons gan be generated on the handle in any orientation within approximately 25 mm from the display. Tool position and orientation feedback is provided by an optical motion tracking sensor and infrared LEDs on the tool handle. The design and analysis of the prototype system is presented with results from a simple interactive environment.