This chapter gives a brief overview of the DLR MiroSurge versatile surgical robotic demonstrator, its major components, mechatronic design and control paradigms. Central component is the robot arm Miro based on intelligent mechatronic technology developed at DLR. The system is adapted to various medical applications by attaching various instruments, e.g., the dedicated instrument MICA, and a surgeon workstation providing HD 3D vision and haptic feedback. Furthermore, a selection of current research topics concerning novel MIRS applications and system components are introduced.

A fiber optic curvature sensor based on discrete Fiber Bragg gratings inscribed in a multi-core fiber is presented. The individual cores of the multi-core fiber are each interrogated by a custom-built spectrometer running at up to 20 kHz. They are interfaced with a custom-tapered combiner of single-core fibers fusion spliced to the multi-core fiber. The curvature and bend direction for each fiber segment is obtained from the geometric relation of strain measurements in all interrogated fiber cores, thus eliminating temperature influences and minimizing noise. In order to reconstruct the shape of the measurement fiber, both constant curvature and spline interpolation using homogeneous transformation matrices are performed and compared to given free space equilibrium state solutions for a Kirchhoff elastic rod.

This document presents the design of a 6-degree of freedom fiberoptic force-torque-sensor for integration in instruments for minimally invasive robotic surgery. The measuring system based on fiber Bragg gratings as well as the calibration procedure are explained. Measurement properties of the sensor are verified in a test setup.

An anthropomorphic hand arm system using variable stiffness actuation has been developed at DLR. It is aimed to reach its human archetype regarding size, weight and performance. The main focus of our development is put on robustness, dynamic performance and dexterity. Therefore, a paradigm change from impedance controlled, but mechanically stiff joints to robots using intrinsic variable compliance joints is carried out. Collisions of the rigid joint robot at high speeds with stiff objects induce the energy too fast for an active controller to prevent damages. In contrast, passively compliant robots are able to temporarily store energy. In this case the resulting internal forces applied to the robot structure and the drive trains are reduced. Furthermore, the energy storage allows to outperform the dynamics of stiff robots. The hand drives and the electronics are completely integrated within the forearm. Extremely miniaturized electronics have been developed to drive the 52 motors of the system and interface their sensors. Several variable stiffness actuation principles used in the arm joints and the hand are presented. The paper highlights the different requirements that they have to fulfill. A first test of the systems robustness and dynamics has been performed by driving nails with a grasped hammer and is demonstrated in the attached video.

This paper presents MiroSurge, a telepresence system for minimally invasive surgery developed at the German Aerospace Center (DLR), and introduces MiroSurge's new user interaction modalities: (1) haptic feedback with software-based preservation of the fulcrum point, (2) an ultrasound-based approach to the quasi-tactile detection of pulsating vessels, and (3) a contact-free interface between surgeon and telesurgery system, where stereo vision is augmented with force vectors at the tool tip. All interaction modalities aim to increase the user's perception beyond stereo imaging by either augmenting the images or by using haptic interfaces. MiroSurge currently provides surgeons with two different interfaces. The first option, bimanual haptic interaction with force and partial tactile feedback, allows for direct perception of the remote environment. Alternatively, users can choose to control the surgical instruments by optically tracked forceps held in their hands. Force feedback is then provided in augmented stereo images by constantly updated force vectors displayed at the centers of the teleoperated instruments, regardless of the instruments' position within the video image. To determine the centerpoints of the instruments, artificial markers are attached and optically tracked. A new approach to detecting pulsating vessels beneath covering tissue with an omnidirectional ultrasound Doppler sensor is presented. The measurement results are computed and can be provided acoustically (by displaying the typical Doppler sound), optically (by augmenting the endoscopic video stream), or kinesthetically (by a gentle twitching of the haptic input devices). The control structure preserves the fulcrum point in minimally invasive surgery and user commands are followed by the surgical instrument. Haptic feedback allows the user to distinguish between interaction with soft and hard environments. The paper includes technical evaluations of the features presented, as well as an overview of the system integration of MiroSurge.

In minimally invasive robotic surgery long and slender instruments are introduced into the body of the patient through small incisions or natural orifices. Robotics technology is applied in order to comply with the kinematic constraints of the fulcrum point, to increase the immersion for the surgeon by sensors and to increase dexterity by supplemental motion capabilities.