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

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

Human adaptive haptic sensing

How do humans physically interact with the environment or with other humans? It is well known that the nervous system can modify the body’s stiffness by selectively cocontracting muscles to shape the mechanical interaction with the environment, but how this influences haptic perception is not known. This thesis examines whether humans can adapt muscles’ activation to influence their perception of the physical interaction with the environment. This question is investigated by conducting behavioural experiments using dedicated robotic interfaces to study sensorimotor interactions in the presence of haptic and visual perturbations. Hypotheses about the underlying mechanism are then tested through mathematical modelling and simulations. Chapter 1 reviews related frameworks and introduces the most relevant questions addressed in this work. Chapter 2 then shows that the central nervous system (CNS) can voluntarily adapt muscle cocontraction to increase haptic sensitivity. In an experiment, participants tracked a randomly moving target with visual noise while being physically guided by a virtual elastic band, where the band’s stiffness was controlled by their muscle coactivation. The results show that participants learned to increase cocontraction with visual noise and decrease it when the guidance is incongruent with the visual target. The adaptation law governing the regulation of the body’s stiffness by the CNS is then derived through computational modelling. This model is designed to maximise visuo-haptic information while minimising metabolic cost, thus trading off sensory information with energy. Further, it is shown in Chapter 3 that when the subjects are coupled via a tuneable connection to a robotic guidance designed to hinder their tracking through perturbations at the turning points (where participants physiologically increase cocontraction), they adapted cocontraction to reduce the impact of perturbations on performance. These results highlight the CNS ability to modify the muscle activation patterns to improve performance with minimal effort. Chapter 4 tests the robustness of human adaptive haptic sensing introduced in the previous chapters for human-human physical interaction. For example, in tango dancing physical contact provides haptic information of the partner’s action required to coordinate the movements. During such physical interactions, should one keep the arms compliant so that the partner can correct the motion, or should one stiffen them to better keep along the planned movement? Using a tracking task in which a dyad is coupled via a rigid connection, subjects readily adapted the compliance of their limb depending on both the accuracy of the partner’s and their own movement. The same computational model introduced in Chapter 2 could explain these results and predict the experimentally observed cocontraction adaptation. This suggests that the minimisation of prediction error and energy is a general principle also holding in interpersonal interactions. Altogether, these findings shed light on how humans can adapt haptic sensing by changing body properties, and propose a novel framework to interpret visuo-haptic perception for interaction with the environment and other humans.Open Acces

Haptic Enhancement of Sensorimotor Learning for Clinical Training Applications

Modern surgical training requires radical change with the advent of increasingly complex procedures, restricted working hours, and reduced ‘hands-on’ training in the operating theatre. Moreover, an increased focus on patient safety means there is a greater need to objectively measure proficiency in trainee surgeons. Indeed, the existing evidence suggests that surgical sensorimotor skill training is not adequate for modern surgery. This calls for new training methodologies which can increase the acquisition rate of sensorimotor skill. Haptic interventions offer one exciting possible avenue for enhancing surgical skills in a safe environment. Nevertheless, the best approach for implementing novel training methodologies involving haptic intervention within existing clinical training curricula has yet to be determined. This thesis set out to address this issue. In Chapter 2, the development of two novel tools which enable the implementation of bespoke visuohaptic environments within robust experimental protocols is described. Chapters 3 and 4 report the effects of intensive, long-term training on the acquisition of a compliance discrimination skill. The results indicate that active behaviour is intrinsically linked to compliance perception, and that long-term training can help to improve the ability of detecting compliance differences. Chapter 5 explores the effects of error augmentation and parameter space exploration on the learning of a complex novel task. The results indicate that error augmentation can help improve learning rate, and that physical workspace exploration may be a driver for motor learning. This research is a first step towards the design of objective haptic intervention strategies to help support the rapid acquisition of sensorimotor skill. The work has applications in clinical settings such as surgical training, dentistry and physical rehabilitation, as well as other areas such as sport

Computer-Aided Bilateral Teleoperation of Manipulators

Haptic bilateral teleoperation is often a challenging and mentally demanding job for the operators of robot control systems. It is especially difficult in cases such as the remote maintenance of the ITER divertor region. The difficulty of the ITER divertor maintenance hails from a multitude of reasons: the residual radiation level of the ITER reactor during a shutdown is too high for any human access, the maintenance tunnels of the divertor are confined, the operators have to operate heavy loads in delicate tasks, and only a limited number of radiation tolerant cameras are available for providing video feedback. In addition, most of the maintenance work cannot be automated because of the dynamic nature and complexity of the tasks. Haptic shared control systems can be used for reducing the amount of mental and physical workload perceived by the operators of remote maintenance systems. To reduce the workload, a haptic shared control system assists the operators by generating virtual forces based on the virtual models of the teleoperation environment and sensor data from the slave manipulator. The generated assistance forces are laid over the force feedback signals from the teleoperation environment. The assisting forces can e.g. guide the operators along optimal paths and prevent collisions in the teleoperation environment. In addition to the reduction of the operator workload, teleoperation tasks also become faster and safer with haptic shared control. This thesis investigates the implementation techniques and theory of haptic bilateral teleoperation and shared control systems. Based on the theoretical analysis, an experimental haptic shared control system, called the Computer Assisted Teleoperation (CAT) was developed. The intention of CAT is to assist the remote handling (RH) system operators of the Divertor Test Platform 2 (DTP2) in ITER remote maintenance research. The effectiveness of CAT is evaluated in a teleoperation experiment performed with a 6 DOF Water Hydraulic MANipulator (WHMAN) developed for the ITER divertor maintenance. The results of the experiment gives directive indication that the CAT system improves the execution times of a bilateral teleoperation task and simultaneously reduces the workload perceived by the operators of the system

Construcción de un módulo de paleta háptica para desarrollar prácticas de laboratorio de sistemas dinámicos en la carrera de Ingeniería en Mecatrónica

Construir un módulo de paleta háptica para desarrollar prácticas de laboratorio de sistemas dinámicos, en la carrera de Ingeniería en Mecatrónica.En el presente proyecto se detalla el desarrollo del módulo de paleta háptica, una investigación realizada con el objetivo de construir un dispositivo capaz de transmitir al usuario los sistemas dinámicos simulados y ser capaz de realizar actividades de control. El módulo de paleta háptica está constituido por una palanca de mando de fuerza de respuesta de un solo eje. La parte electrónica esta implementada por: un actuador, un sistema sensorial con un sensor de posición angular y un microcontrolador Arduino. La comunicación e interconexión para el control de la planta se desarrolla en LabVIEW. En este trabajo se planteó una nueva práctica educativa que se llevó a cabo gracias a la paleta háptica de bajo costo construida en la Universidad Técnica del Norte, centrándose principalmente en añadir una actividad de práctica realizable con el módulo, el uso de este como equipo de práctica en el tema de oscilaciones, presentando el experimento de movimiento armónico y movimiento amortiguado. A nivel de Ecuador e Imbabura se implementó el primer módulo de paleta háptica con cambios electrónicos y de software, presentando el cambio en su interfaz de control, sin dejar de lado las características que identifica a la paleta háptica de otras universidades, esto como un gran aporte al aprendizaje en el proceso de enseñanza que se llevó a cabo en la universidad Técnica del Norte, siendo base para el desarrollo de futuros trabajos de investigación en dispositivos hápticos

Hands-on learning with a series elastic educational robot

For gaining proficiency in physical human-robot interaction (pHRI), it is crucial for engineering students to be provided with the opportunity to physically interact with and gain hands-on experience on design and control of force-feedback robotic devices. We present a single degree of freedom educational robot that features series elastic actuation and relies on closed loop force control to achieve the desired level of safety and transparency during physical interactions. The proposed device complements the existing impedance-type Haptic Paddle designs by demonstrating the challenges involved in the synergistic design and control of admittance-type devices. We present integration of this device into pHRI education, by providing guidelines for the use of the device to allow students to experience the performance trade-offs inherent in force control systems, due to the non-collocation between the force sensor and the actuator. These exercises enable students to modify the mechanical design in addition to the controllers, by assigning different levels of stiffness values to the compliant element, and characterize the effects of these design choices on the closed-loop force control performance of the device. We also report initial evaluations of the efficacy of the device for pHRI studies

Electroencephalographic Responses to Frictional Stimuli: Measurement Setup and Processing Pipeline

Tactility is a key sense in the human interaction with the environment. The understanding of tactile perception has become an exciting area in industrial, medical and scienti c research with an emphasis on the development of new haptic technologies. Surprisingly, the quanti cation of tactile perception has, compared to other senses, only recently become a eld of scienti c investigation. The overall goal of this emerging scienti c discipline is an understanding of the causal chain from the contact of the skin with materials to the brain dynamics representing recognition of and emotional reaction to the materials. Each link in this chain depends on individual and environmental factors ranging from the in uence of humidity on contact formation to the role of attention for the perception of touch. This thesis reports on the research of neural correlates to the frictional stimulation of the human ngertip. Event-related electroencephalographic potentials (ERPs) upon the change in ngertip friction are measured and studied, when pins of a programmable Braille-display were brought into skin contact. In order to contribute to the understanding of the causal chain mentioned above, this work combines two research areas which are usually not connected to each other, namely tribology and neuroscience. The goal of the study is to evaluate contributions of friction to the process of haptic perception. Key contributions of this thesis are: 1) Development of a setup to simultaneously record physical forces and ERPs upon tactile stimulation. 2) Implementation of a dedicated signal processing pipeline for the statistical analysis of ERP -amplitudes, -latencies and -instantaneous phases. 3) Interpretation of skin friction data and extraction of neural correlates with respect to varying friction intensities. The tactile stimulation of the ngertip upon raising and lowering of di erent lines of Braille-pins (one, three and ve) caused pronounced N50 and P100 components in the event-related ERPsequences, which is in line with the current literature. Friction between the ngertip and the Braille-system exhibited a characteristic temporal development which is attributed to viscoelastic skin relaxation. Although the force stimuli varied by a factor of two between the di erent Braillepatterns, no signi cant di erences were observed between the amplitudes and latencies of ERPs after standard across-trial averaging. Thus, for the rst time a phase measure for estimating singletrial interactions of somatosensory potentials is proposed. Results show that instantaneous phase coherency is evoked by friction, and that higher friction induces stronger and more time-localized phase coherencyDie Taktilität ist ein zentraler Sinn in der Interaktion mit unserer Umwelt. Das Bestreben, fundierte Erkenntnisse hinsichtlich der taktilenWahrnehmung zu gewinnen erhält groÿen Zuspruch in der industriellen, medizinischen und wissenschaftlichen Forschung, meist mit einem Fokus auf der Entwicklung von haptischen Technologien. Erstaunlicherweise ist jedoch die wissenschaftliche Quanti zierung der taktilen Wahrnehmung, verglichen mit anderen Sinnesmodalitäten, erst seit kurzem ein sich entwickelnder Forschungsbereich. Fokus dieser Disziplin ist es, die kognitive und emotionale Reaktion nach physischem Kontakt mit Materialien zu beschreiben, und die kausale Wirkungskette von der Berührung bis zur Reaktion zu verstehen. Dabei unterliegen die einzelnen Faktoren dieser Kette sowohl individuellen als auch externen Ein üssen, welche von der Luftfeuchtigkeit während des Kontaktes bis hin zur Rolle der Aufmerksamkeit für die Wahrnehmung reichen. Die vorliegende Arbeit beschäftigt sich mit der Untersuchung von neuronalen Korrelaten nach Reibungsstimulation des menschlichen Fingers. Dazu wurden Reibungsänderungen, welche durch den Kontakt der menschlichen Fingerspitze mit schaltbaren Stiften eines Braille-Display erzeugt wurden, untersucht und die entsprechenden neuronalen Korrelate aufgezeichnet. Um zu dem Verst ändnis der oben erwähnten Wirkungskette beizutragen, werden Ansätze aus zwei für gewöhnlich nicht zusammenhängenden Forschungsbereichen, nämlich der Tribologie und der Neurowissenschaft, kombiniert. Folgende Beiträge sind Hauptbestandteile dieser Arbeit: 1) Realisierung einer Messumgebung zur simultanen Ableitung von Kräften und ereigniskorrelierten Potentialen nach taktiler Stimulation der Fingerspitze. 2) Aufbau einer speziellen Signalverarbeitungskette zur statistischen Analyse von stimulationsabh ängigen EEG -Amplituden, -Latenzen und -instantanen Phasen. 3) Interpretation der erhobenen Reibungsdaten und Extraktion neuronaler Korrelate hinsichtlich variierender Stimulationsintensitäten. Unsere Resultate zeigen, dass die taktile Stimulation der Fingerspitze nach Anheben und Senken von Braille-Stiften zu signi kanten N50 und P100 Komponenten in den ereigniskorrelierten Potentialen führt, im Einklang mit der aktuellen Literatur. Die Reibung zwischen der Fingerspitze und dem Braille-System zeigte einen charakteristischen Signalverlauf, welcher auf viskoelastische Hautrelaxation zurückzuführen ist. Trotz der um einen Faktor zwei verschiedenen Intensit ätsunterschiede zwischen den Stimulationsmustern zeigten sich keine signi kanten Unterschiede zwischen den einfach gemittelten Amplituden der evozierten Potentialen. Erstmalig wurde ein Phasen-Maÿ zur Identi zierung von Unterschieden zwischen somatosensorischen "single-trial" Interaktionen angewandt. Diese Phasenanalyse zeigte, im Gegensatz zur Amplituden- und Latenzanalyse, deutlichere und signi kantere Unterschiede zwischen den Stimulationsparadigmen. Es wird gefolgert, dass Kohärenz zwischen den Momentanphasen durch Reibungsereignisse herbeigef ührt wird und dass durch stärkere Reibung diese Kohärenz, im zeitlichen Verlauf, stärker und lokalisierter wird