Ulrich Hagn

The DLR hand arm system

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.

DLR MiroSurge: a versatile system for research in endoscopic telesurgery.

PurposeResearch on surgical robotics demands systems for evaluating scientific approaches. Such systems can be divided into dedicated and versatile systems. Dedicated systems are designed for a single surgical task or technique, whereas versatile systems are designed to be expandable and useful in multiple surgical applications. Versatile systems are often based on industrial robots, though, and because of this, are hardly suitable for close contact with humans.MethodTo achieve a high degree of versatility the Miro robotic surgery platform (MRSP) consists of versatile components, dedicated front–ends towards surgery and configurable interfaces for the surgeon.ResultsThis paper presents MiroSurge, a configuration of the MRSP that allows for bimanual endoscopic telesurgery with force feedback.ConclusionsWhile the components of the MiroSurge system are shown to fulfil the rigid design requirements for robotic telesurgery with force feedback, the system remains versatile, which is supposed to be a key issue for the further development and optimisation.

The DLR MIRO: a versatile lightweight robot for surgical applications

Purpose – Surgical robotics can be divided into two groups: specialized and versatile systems. Versatile systems can be used in different surgical applications, control architectures and operating room set‐ups, but often still based on the adaptation of industrial robots. Space consumption, safety and adequacy of industrial robots in the unstructured and crowded environment of an operating room and in close human robot interaction are at least questionable. The purpose of this paper is to describe the DLR MIRO, a new versatile lightweight robot for surgical applications.Design/methodology/approach – The design approach of the DLR MIRO robot focuses on compact, slim and lightweight design to assist the surgeon directly at the operating table without interference. Significantly reduced accelerated masses (total weight 10 kg) enhance the safety of the system during close interaction with patient and user. Additionally, MIRO integrates torque‐sensing capabilities to enable close interaction with human beings ...

A hands-on-robot for accurate placement of pedicle screws

This paper presents a novel system for accurate placement of pedicle screws. The system consists of a new light-weight (<10 kg), kinematically redundant, and fully torque controlled robot. Additionally, the pose of the robot tool-center point is tracked by an optical navigation system, serving as an external reference source. Therefore, it is possible to measure and to compensate deviations between the intraoperative and the preoperatively planned pose. The robotic arm itself is impedance controlled. This allows for a new intuitive man-machine-interface as the joint units are equipped with torque sensors: the robot can be moved just by pulling/pushing its structure. The surgeon has full control of the robot at every step of the intervention. The hand-eye-coordination problems known from manual pedicle screw placement can be omitted

MICA - A new generation of versatile instruments in robotic surgery

Robotic surgery systems are highly complex and expensive pieces of equipment. Demands for lower cost of care can be met if these systems are employable in a flexible manner for a large variety of procedures. To protect the initial investment the capabilities of a robotic system need to be expandable as new tasks arise.

The sigma.7 haptic interface for MiroSurge: A new bi-manual surgical console

This paper presents the design and control of the sigma.7 haptic device and the new surgical console of the MiroSurge robotic system. The console and the haptic devices are designed with respect to requirements in minimally invasive robotic surgery. Dedicated left and right handed devices are integrated in an operator console in an ergonomic configuration. The height of the whole console is adjustable, allowing the surgeon seated and standed operation. Each of the devices is fully actuated in seven degrees of freedom (DoF). A parallel mechanism with 3 DoF actuates the translational motion and an attached wrist with 3 intersecting axis drives the rotations of the grasping unit. This advantageous design leads to inherently decoupled kinematics and dynamics. Cartesian forces are 20 N within the translational workspace, which is a sphere of about 120 mm diameter for each device. The rotational wrist of the device covers the whole workspace of the human hand and provides maximum torques of about 0.4 Nm. The grasping unit can display forces up to 8 N. An integrated force/torque sensor is used to increase the transparency of the devices by reducing inertia and friction. It is theoretically shown that the non-linear closed loop system behaves like a passive system and experimental results validate the approach. The sigma.7 haptic devices are designed by Force Dimension in cooperation with the German Aerospace Center (DLR). DLR designed the surgical console and integrated the haptic devices in the MiroSurge system.

The DLR MiroSurge - A robotic system for surgery

This video presents the in-house developed DLR MiroSurge robotic system for surgery. As shown, the system is suitable for both minimally invasive and open surgery. Essential part of the system is the MIRO robot: The soft robotics feature enables intuitive interaction with the robot.

Kinematic Design Optimization of an Actuated Carrier for the DLR Multi-Arm Surgical System

In this paper, a generic approach to optimize the design of an actuated carrier for the DLR multi-arm surgical system is presented. The carrier is attached to the ceiling of the operating room and provides additional degrees of freedom to the surgical robots with the purpose of automatic, optimal positioning of their bases as well as guaranteeing high stiffness. Standard workspaces of minimally invasive as well as open surgical procedures are considered and optimization criteria are derived. The minimum necessary degrees of freedom of the carrier are obtained as well as the optimal segment dimensions by use of an optimization with genetic algorithms

New method for detection of complex 3D fracture motion - Verification of an optical motion analysis system for biomechanical studies

BackgroundFracture-healing depends on interfragmentary motion. For improved osteosynthesis and fracture-healing, the micromotion between fracture fragments is undergoing intensive research. The detection of 3D micromotions at the fracture gap still presents a challenge for conventional tactile measurement systems. Optical measurement systems may be easier to use than conventional systems, but, as yet, cannot guarantee accuracy. The purpose of this study was to validate the optical measurement system PONTOS 5M for use in biomechanical research, including measurement of micromotion.MethodsA standardized transverse fracture model was created to detect interfragmentary motions under axial loadings of up to 200 N. Measurements were performed using the optical measurement system and compared with a conventional high-accuracy tactile system consisting of 3 standard digital dial indicators (1 μm resolution; 5 μm error limit).ResultsWe found that the deviation in the mean average motion detection between the systems was at most 5.3 μm, indicating that detection of micromotion was possible with the optical measurement system. Furthermore, we could show two considerable advantages while using the optical measurement system. Only with the optical system interfragmentary motion could be analyzed directly at the fracture gap. Furthermore, the calibration of the optical system could be performed faster, safer and easier than that of the tactile system.ConclusionThe PONTOS 5 M optical measurement system appears to be a favorable alternative to previously used tactile measurement systems for biomechanical applications. Easy handling, combined with a high accuracy for 3D detection of micromotions (≤ 5 μm), suggests the likelihood of high user acceptance. This study was performed in the context of the deployment of a new implant (dynamic locking screw; Synthes, Oberdorf, Switzerland).

A Co-Robotic Positioning Device for Carrying Surgical End-Effectors

The development of a remotely operated, Co-Robotic Positioning Device (CRPD) for instrumental backing and optimal base position to robotic arms in tele-surgery is discussed. To optimise the setting of robotic operating rooms (ROR) by reducing the structures’ size around the patient and by selecting task-driven layouts, the design of a hanging servo-carrier coming from the ceiling is chosen, rather than a device located on the floor. The present study prospects a split-duty approach, distinguishing the Co-Robotic Positioning Device, CRPD, from the front-end effectors, each subsystem hierarchically controlled by remote location, in keeping with optimal protocols. The attention is focused on the slave-carrier, to establish an optimal design of the CRPD, based on the characteristics of robotic effectors and the surgical task. The CRPD is conceived to support (up to four) robotic effectors, each one equipped with proper tools (endoscope, scalpels, scissors, suture needles, etc.). The CRPD, actually, by optimally positioning the robotic arms, avoids the need of manual deployment, in current setups often necessary to avoid singularities or collisions. The Automatic Changing Device for Surgical Tools, ACD-ST, is another significant device of the conceived slave-carrier. It allows the tele-operating surgeon to change the tools (scalpels, scissors, etc.) by a direct command from his console. Example applications aim at ticklish endoscopic/tomic operations that require high accuracy with low involved forces such as cardio-thoracic-surgery, abdominal surgery, spine-surgery, microsurgery (neurosurgery, hand-surgery, ophthalmic-surgery, ear-nose-throat surgery), say, the typical domains of MIRS, where robotic surgery is quickly expanding.Copyright