Design of a six degree-of-freedom haptic hybrid platform manipultor

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2010Includes bibliographical references (leaves: 97-103)Text in English; Abstract: Turkish and Englishxv, 115 leavesThe word Haptic, based on an ancient Greek word called haptios, means related with touch. As an area of robotics, haptics technology provides the sense of touch for robotic applications that involve interaction with human operator and the environment. The sense of touch accompanied with the visual feedback is enough to gather most of the information about a certain environment. It increases the precision of teleoperation and sensation levels of the virtual reality (VR) applications by exerting physical properties of the environment such as forces, motions, textures. Currently, haptic devices find use in many VR and teleoperation applications. The objective of this thesis is to design a novel Six Degree-of-Freedom (DOF) haptic desktop device with a new structure that has the potential to increase the precision in the haptics technology. First, previously developed haptic devices and manipulator structures are reviewed. Following this, the conceptual designs are formed and a hybrid structured haptic device is designed manufactured and tested. Developed haptic device.s control algorithm and VR application is developed in Matlab© Simulink. Integration of the mechanism with mechanical, electromechanical and electronic components and the initial tests of the system are executed and the results are presented. According to the results, performance of the developed device is discussed and future works are addressed

Haptic Device Design and Teleoperation Control Algorithms for Mobile Manipulators

The increasing need of teleoperated robotic systems implies more and more often to use, as slave devices, mobile platforms (terrestrial, aerial or underwater) with integrated manipulation capabilities, provided e.g. by robotic arms with proper grasping/manipulation tools. Despite this, the research activity in teleoperation of robotic systems has mainly focused on the control of either fixed-base manipulators or mobile robots, non considering the integration of these two types of systems in a single device. Such a combined robotic devices are usually referred to as mobile manipulators: systems composed by both a robotic manipulator and a mobile platform (on which the arm is mounted) whose purpose is to enlarge the manipulator’s workspace. The combination of a mobile platform and a serial manipulator creates redundancy: a particular point in the space can be reached by moving the manipulator, by moving the mobile platform, or by a combined motion of both. A synchronized motion of both devices need then to be addressed. Although specific haptic devices explicitly oriented to the control of mobile manipulators need to be designed, there are no commercial solution yet. For this reason it is often necessary to control such as combined systems with traditional haptic devices not specifically oriented to the control of mobile manipulators. The research activity presented in this Ph.D. thesis focuses in the first place on the design of a teleoperation control scheme which allows the simultaneous control of both the manipulator and the mobile platform by means of a single haptic device characterized by fixed base and an open kinematic chain. Secondly the design of a novel cable-drive haptic devices has been faced. Investigating the use of twisted strings actuation in force rendering is the most interesting challenge of the latter activity

Haptics-Enabled Teleoperation for Robotics-Assisted Minimally Invasive Surgery

The lack of force feedback (haptics) in robotic surgery can be considered to be a safety risk leading to accidental tissue damage and puncturing of blood vessels due to excessive forces being applied to tissue and vessels or causing inefficient control over the instruments because of insufficient applied force. This project focuses on providing a satisfactory solution for introducing haptic feedback in robotics-assisted minimally invasive surgical (RAMIS) systems. The research addresses several key issues associated with the incorporation of haptics in a master-slave (teleoperated) robotic environment for minimally invasive surgery (MIS). In this project, we designed a haptics-enabled dual-arm (two masters - two slaves) robotic MIS testbed to investigate and validate various single-arm as well as dual-arm teleoperation scenarios. The most important feature of this setup is the capability of providing haptic feedback in all 7 degrees of freedom (DOF) required for RAMIS (3 translations, 3 rotations and pinch motion of the laparoscopic tool). The setup also enables the evaluation of the effect of replacing haptic feedback by other sensory cues such as visual representation of haptic information (sensory substitution) and the hypothesis that surgical outcomes may be improved by substituting or augmenting haptic feedback by such sensory cues

Haptic-Based Shared-Control Methods for a Dual-Arm System

We propose novel haptic guidance methods for a dual-arm telerobotic manipulation system, which are able to deal with several different constraints, such as collisions, joint limits, and singularities. We combine the haptic guidance with shared-control algorithms for autonomous orientation control and collision avoidance meant to further simplify the execution of grasping tasks. The stability of the overall system in various control modalities is presented and analyzed via passivity arguments. In addition, a human subject study is carried out to assess the effectiveness and applicability of the proposed control approaches both in simulated and real scenarios. Results show that the proposed haptic-enabled shared-control methods significantly improve the performance of grasping tasks with respect to the use of classic teleoperation with neither haptic guidance nor shared control

Integration of the hybrid-structure haptic interface: HIPHAD v1.0

Design, manufacturing, integration and initial test results of the 6-DoF haptic interface, HIPHAD v1.0, are presented in this paper. The hybrid haptic robot mechanism is composed of a 3-DoF parallel platform manipulator, R-Cube, for translational motions and a 3-DoF serial wrist mechanism for monitoring the rotational motions of the handle. The device is capable of displaying point-type of contact since only the R-Cube mechanism is actuated. The dimensions and the orientation of the R-Cube mechanism are reconfigured to comply with the requirements of the haptic system design criteria. The system has several advantages such as relatively trivial kinematical analysis, compactness and high stiffness. The integration of the system along with its mechanism, data acquisition card (DAQ), motor drivers, motors, position sensors, and computer control interface are outlined.Marie Curie International Reintegration Grant within the 7th European Community Framework Programm

A continuum robotic platform for endoscopic non-contact laser surgery: design, control, and preclinical evaluation

The application of laser technologies in surgical interventions has been accepted in the clinical domain due to their atraumatic properties. In addition to manual application of fibre-guided lasers with tissue contact, non-contact transoral laser microsurgery (TLM) of laryngeal tumours has been prevailed in ENT surgery. However, TLM requires many years of surgical training for tumour resection in order to preserve the function of adjacent organs and thus preserve the patient’s quality of life. The positioning of the microscopic laser applicator outside the patient can also impede a direct line-of-sight to the target area due to anatomical variability and limit the working space. Further clinical challenges include positioning the laser focus on the tissue surface, imaging, planning and performing laser ablation, and motion of the target area during surgery. This dissertation aims to address the limitations of TLM through robotic approaches and intraoperative assistance. Although a trend towards minimally invasive surgery is apparent, no highly integrated platform for endoscopic delivery of focused laser radiation is available to date. Likewise, there are no known devices that incorporate scene information from endoscopic imaging into ablation planning and execution. For focusing of the laser beam close to the target tissue, this work first presents miniaturised focusing optics that can be integrated into endoscopic systems. Experimental trials characterise the optical properties and the ablation performance. A robotic platform is realised for manipulation of the focusing optics. This is based on a variable-length continuum manipulator. The latter enables movements of the endoscopic end effector in five degrees of freedom with a mechatronic actuation unit. The kinematic modelling and control of the robot are integrated into a modular framework that is evaluated experimentally. The manipulation of focused laser radiation also requires precise adjustment of the focal position on the tissue. For this purpose, visual, haptic and visual-haptic assistance functions are presented. These support the operator during teleoperation to set an optimal working distance. Advantages of visual-haptic assistance are demonstrated in a user study. The system performance and usability of the overall robotic system are assessed in an additional user study. Analogous to a clinical scenario, the subjects follow predefined target patterns with a laser spot. The mean positioning accuracy of the spot is 0.5 mm. Finally, methods of image-guided robot control are introduced to automate laser ablation. Experiments confirm a positive effect of proposed automation concepts on non-contact laser surgery.Die Anwendung von Lasertechnologien in chirurgischen Interventionen hat sich aufgrund der atraumatischen Eigenschaften in der Klinik etabliert. Neben manueller Applikation von fasergeführten Lasern mit Gewebekontakt hat sich die kontaktfreie transorale Lasermikrochirurgie (TLM) von Tumoren des Larynx in der HNO-Chirurgie durchgesetzt. Die TLM erfordert zur Tumorresektion jedoch ein langjähriges chirurgisches Training, um die Funktion der angrenzenden Organe zu sichern und damit die Lebensqualität der Patienten zu erhalten. Die Positionierung des mikroskopis chen Laserapplikators außerhalb des Patienten kann zudem die direkte Sicht auf das Zielgebiet durch anatomische Variabilität erschweren und den Arbeitsraum einschränken. Weitere klinische Herausforderungen betreffen die Positionierung des Laserfokus auf der Gewebeoberfläche, die Bildgebung, die Planung und Ausführung der Laserablation sowie intraoperative Bewegungen des Zielgebietes. Die vorliegende Dissertation zielt darauf ab, die Limitierungen der TLM durch robotische Ansätze und intraoperative Assistenz zu adressieren. Obwohl ein Trend zur minimal invasiven Chirurgie besteht, sind bislang keine hochintegrierten Plattformen für die endoskopische Applikation fokussierter Laserstrahlung verfügbar. Ebenfalls sind keine Systeme bekannt, die Szeneninformationen aus der endoskopischen Bildgebung in die Ablationsplanung und -ausführung einbeziehen. Für eine situsnahe Fokussierung des Laserstrahls wird in dieser Arbeit zunächst eine miniaturisierte Fokussieroptik zur Integration in endoskopische Systeme vorgestellt. Experimentelle Versuche charakterisieren die optischen Eigenschaften und das Ablationsverhalten. Zur Manipulation der Fokussieroptik wird eine robotische Plattform realisiert. Diese basiert auf einem längenveränderlichen Kontinuumsmanipulator. Letzterer ermöglicht in Kombination mit einer mechatronischen Aktuierungseinheit Bewegungen des Endoskopkopfes in fünf Freiheitsgraden. Die kinematische Modellierung und Regelung des Systems werden in ein modulares Framework eingebunden und evaluiert. Die Manipulation fokussierter Laserstrahlung erfordert zudem eine präzise Anpassung der Fokuslage auf das Gewebe. Dafür werden visuelle, haptische und visuell haptische Assistenzfunktionen eingeführt. Diese unterstützen den Anwender bei Teleoperation zur Einstellung eines optimalen Arbeitsabstandes. In einer Anwenderstudie werden Vorteile der visuell-haptischen Assistenz nachgewiesen. Die Systemperformanz und Gebrauchstauglichkeit des robotischen Gesamtsystems werden in einer weiteren Anwenderstudie untersucht. Analog zu einem klinischen Einsatz verfolgen die Probanden mit einem Laserspot vorgegebene Sollpfade. Die mittlere Positioniergenauigkeit des Spots beträgt dabei 0,5 mm. Zur Automatisierung der Ablation werden abschließend Methoden der bildgestützten Regelung vorgestellt. Experimente bestätigen einen positiven Effekt der Automationskonzepte für die kontaktfreie Laserchirurgie

Design, Development, and Evaluation of a Teleoperated Master-Slave Surgical System for Breast Biopsy under Continuous MRI Guidance

The goal of this project is to design and develop a teleoperated master-slave surgical system that can potentially assist the physician in performing breast biopsy with a magnetic resonance imaging (MRI) compatible robotic system. MRI provides superior soft-tissue contrast compared to other imaging modalities such as computed tomography or ultrasound and is used for both diagnostic and therapeutic procedures. The strong magnetic field and the limited space inside the MRI bore, however, restrict direct means of breast biopsy while performing real-time imaging. Therefore, current breast biopsy procedures employ a blind targeting approach based on magnetic resonance (MR) images obtained a priori. Due to possible patient involuntary motion or inaccurate insertion through the registration grid, such approach could lead to tool tip positioning errors thereby affecting diagnostic accuracy and leading to a long and painful process, if repeated procedures are required. Hence, it is desired to develop the aforementioned teleoperation system to take advantages of real-time MR imaging and avoid multiple biopsy needle insertions, improving the procedure accuracy as well as reducing the sampling errors. The design, implementation, and evaluation of the teleoperation system is presented in this dissertation. A MRI-compatible slave robot is implemented, which consists of a 1 degree of freedom (DOF) needle driver, a 3-DOF parallel mechanism, and a 2-DOF X-Y stage. This slave robot is actuated with pneumatic cylinders through long transmission lines except the 1-DOF needle driver is actuated with a piezo motor. Pneumatic actuation through long transmission lines is then investigated using proportional pressure valves and controllers based on sliding mode control are presented. A dedicated master robot is also developed, and the kinematic map between the master and the slave robot is established. The two robots are integrated into a teleoperation system and a graphical user interface is developed to provide visual feedback to the physician. MRI experiment shows that the slave robot is MRI-compatible, and the ex vivo test shows over 85%success rate in targeting with the MRI-compatible robotic system. The success in performing in vivo animal experiments further confirm the potential of further developing the proposed robotic system for clinical applications

Development and evaluation of mixed reality-enhanced robotic systems for intuitive tele-manipulation and telemanufacturing tasks in hazardous conditions

In recent years, with the rapid development of space exploration, deep-sea discovery, nuclear rehabilitation and management, and robotic-assisted medical devices, there is an urgent need for humans to interactively control robotic systems to perform increasingly precise remote operations. The value of medical telerobotic applications during the recent coronavirus pandemic has also been demonstrated and will grow in the future. This thesis investigates novel approaches to the development and evaluation of a mixed reality-enhanced telerobotic platform for intuitive remote teleoperation applications in dangerous and difficult working conditions, such as contaminated sites and undersea or extreme welding scenarios. This research aims to remove human workers from the harmful working environments by equipping complex robotic systems with human intelligence and command/control via intuitive and natural human-robot- interaction, including the implementation of MR techniques to improve the user's situational awareness, depth perception, and spatial cognition, which are fundamental to effective and efficient teleoperation. The proposed robotic mobile manipulation platform consists of a UR5 industrial manipulator, 3D-printed parallel gripper, and customized mobile base, which is envisaged to be controlled by non-skilled operators who are physically separated from the robot working space through an MR-based vision/motion mapping approach. The platform development process involved CAD/CAE/CAM and rapid prototyping techniques, such as 3D printing and laser cutting. Robot Operating System (ROS) and Unity 3D are employed in the developing process to enable the embedded system to intuitively control the robotic system and ensure the implementation of immersive and natural human-robot interactive teleoperation. This research presents an integrated motion/vision retargeting scheme based on a mixed reality subspace approach for intuitive and immersive telemanipulation. An imitation-based velocity- centric motion mapping is implemented via the MR subspace to accurately track operator hand movements for robot motion control, and enables spatial velocity-based control of the robot tool center point (TCP). The proposed system allows precise manipulation of end-effector position and orientation to readily adjust the corresponding velocity of maneuvering. A mixed reality-based multi-view merging framework for immersive and intuitive telemanipulation of a complex mobile manipulator with integrated 3D/2D vision is presented. The proposed 3D immersive telerobotic schemes provide the users with depth perception through the merging of multiple 3D/2D views of the remote environment via MR subspace. The mobile manipulator platform can be effectively controlled by non-skilled operators who are physically separated from the robot working space through a velocity-based imitative motion mapping approach. Finally, this thesis presents an integrated mixed reality and haptic feedback scheme for intuitive and immersive teleoperation of robotic welding systems. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time visual feedback from the robot working space. The proposed mixed reality virtual fixture integration approach implements hybrid haptic constraints to guide the operator’s hand movements following the conical guidance to effectively align the welding torch for welding and constrain the welding operation within a collision-free area. Overall, this thesis presents a complete tele-robotic application space technology using mixed reality and immersive elements to effectively translate the operator into the robot’s space in an intuitive and natural manner. The results are thus a step forward in cost-effective and computationally effective human-robot interaction research and technologies. The system presented is readily extensible to a range of potential applications beyond the robotic tele- welding and tele-manipulation tasks used to demonstrate, optimise, and prove the concepts

A demonstration and comparative analysis of haptic performance using a Gough-Stewart platform as a wearable haptic feedback device

In many hazardous work environments, contact tasks ranging from manufacturing to disassembly to emergency response are performed by industrial manipulators. Due to the hazardous and complex nature of these environments, teleoperation is often employed. When such is the case, the operator is left to interpret a large amount of data during task completion due to the complexity of modern robotic systems and the possible complexity of the tasks. This information is usually processed visually but can lead to sensory overload. To mitigate this, the information processing can also be distributed through other modes of sensory such as auditory or haptic. The University of Texas at Austin's TeMoto hands-free interface reduces the burden on the operator of commanding remote systems by enabling the use of gestural and verbal commands to complete a range of tasks, but the removal of a mechanical interactive device from the operator interface complicates the inclusion of haptic feedback. In this work, a standalone Gough-Stewart platform previously configured as a wearable haptic feedback device for the Nuclear and Applied Robotics Group at the University of Texas at Austin provides real-time haptic feedback to the unconstrained hand(s) of the operator. In doing so, this haptic interface can be employed with the intent of enhancing situational awareness and minimizing operator stress by imparting forces and torques to the user based on those imparted on the end-effector of the industrial manipulator. While multiple technical issues and human factor issues must be addressed, this effort focuses on integrating the system and evaluating its performance for various industrial manipulator designs and sensor modalities. After testing various digital signal processing techniques, functionality was demonstrated among one series-elastic and two rigid industrial manipulators, each with different force/torque data acquisition characteristics and a comparative analysis in haptic performance was performed. Furthermore, it was demonstrated with the TeMoto hands-free teleoperation system. Overall, the demonstrations and experiments performed in this work prove the system to be a viable, hardware agnostic means of haptic feedback and a strong basis for future effortsMechanical Engineerin

Haptic teleoperation of mobile manipulator systems using virtual fixtures.

In order to make the task of controlling Mobile-Manipulator Systems (MMS) simpler, a novel command strategy that uses a single joystick is presented to replace the existing paradigm of using multiple joysticks. To improve efficiency and accuracy, virtual fixtures were implemented with the use of a haptic joystick. Instead of modeling the MMS as a single unit with three redundant degrees-of-freedom (DOF), the operator controls either the manipulator or the mobile base, with the command strategy choosing which one to move. The novel command strategy uses three modes of operation to automatically switch control between the manipulator and base. The three modes of operation are called near-target manipulation mode, off-target manipulation mode, and transportation mode. The system enters near-target manipulation mode only when close to a target of interest, and allows the operator to control the manipulator using velocity control. When the operator attempts to move the manipulator out of its workspace limits, the system temporarily enters transportation mode. When the operator moves the manipulator in a direction towards the manipulator???s workspace the system returns to near-target manipulation mode. In off-target manipulation mode, when the operator moves the manipulator to its workspace limits, the system retracts the arm near to the centre of its workspace to enter and remain in transportation mode. While in transportation mode the operator controls the base using velocity control. Two types of virtual fixtures are used, repulsive virtual fixtures and forbidden region virtual fixtures. Repulsive virtual fixtures are present in the form of six virtual walls forming a cube at the manipulator???s workspace limits. When the operator approaches a virtual wall, a repulsive force is felt pushing the operator???s hand away from the workspace limits. The forbidden region virtual fixtures prevent the operator from driving into obstacles by disregarding motion commands that would result in a collision. The command strategy was implemented on the Omnibot MMS and test results show that it was successful in improving simplicity, accuracy, and efficiency when teleoperating a MMS