Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: This paper reports the results of a pilot study with autistic children based on our recent work examining the potential of combining haptic and sonic exploration with a real painting as a tool for neurorehabilitation. The study consisted of seven children with autism exploring a painting enhanced with haptic and sound feedback. Audio-visual and kinematic data were collected to evaluate the participants’ behaviour and experience. The participants engaged with the interactive experience and interacted with each other in a positive. The results from this study suggest that the interactive painting is a feasible tool for autistic children to use on their own and when they interact with other children.

Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics, Neuro-robotics
Abstract: The hand rehabilitation approach for people who are affected by cerebral apoplexy has been a long-standing issue with researchers worldwide. Currently, scientific research has discovered a way to recover the motor function. Moreover, the sensory function can be recovered by neuroplasticity. Previously, the conventional hand rehabilitation approach only focused on the motor function. Therefore, there is a need to develop an effective hand rehabilitation device to recover both the motor and sensory functions. This research embarked on the configuration setup and evaluation of new hand rehabilitation devices using a mechanical stimulation system. The system has directly led to the stimulation of tactile senses, which can later be used to help patients who lack motor and sensory functions. The work was carried out in four stages comprising the development of a programming algorithm, the design and fabrication of the device and finally, an evaluation of the product and its functions. The objective to develop and fabricate a new robust tactile grasping type stimulator for a hand rehabilitation device has been achieved successfully. The preliminary evaluation on a healthy volunteer was carried out to identify the safety factor in the implementation of hardware and software before targeted patients are used.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Locomotion and manipulation in robots and biological systems
Abstract: Clinical evaluation during walker-assisted gait is the first step to assess the evolution of a patient during rehabilitation and to identify his needs and difficulties. Advances in robotics made it possible to integrate a gait analysis tool on a walker to enrich the existing rehabilitation tests with new sets of objective gait parameters. This paper focuses on the legs detection method to estimate legs position during an assisted walk and the detection of gait events. In this paper, a walker is equipped with a laser range sensor (LRF) and encoders to analyze the spatiotemporal parameters of the walker users. Preliminary results obtained on ten subjects show that relevant data using a LRF can be extracted for gait analysis with a small error.

Keywords: Rehabilitation and assistive robotics, Neuro-robotics, Neuroengineering
Abstract: In this paper, we investigate the feasibility of employing robotics, high-density electroencephalography (EEG), and surface electromyography (EMG) for ankle rehabilitation in a subject with multiple sclerosis (MS). A single session of seated, interactive ankle robot (“Anklebot”) training with concurrent 60-channel EEG and 2-channel EMG monitoring was conducted. The task entailed pointing with the ankle while playing a video game that synchronized ankle movements to guide a screen cursor through 560 moving gates. Practice-induced improvements in multiple motor control measures were accompanied by changes in EEG measures of activation and networking, and in EMG measures indicating greater muscle activity. Our results suggest that Anklebot training and concurrent EEG-EMG monitoring is a feasible approach that may be deployed clinically to advance understanding of the neurophysiological mechanisms in motor-learning based recovery in persons with ankle motor deficits secondary to MS and other neurologic injuries.

Keywords: Rehabilitation and assistive robotics, Neuro-robotics, Human-machine interaction
Abstract: Allien hand syndrome (AHS) is a rare neurological disorder characterised by uncontrollable and involuntary move- ment of upper limb. In Fact, the patient feels it as extraneous part of his/her body. From our knowledge, this paper reports the first results of using robot assisted therapy for rehabilitation of patients with AHS syndrome. It is noticeable that the improvements in the capability of carrying out activities of daily living and in the control of the hand and arm are impressive despite of the progress of her neurodegenerative disease.

Keywords: Human-machine interaction, Neuro-robotics, Neuroengineering
Abstract: Users of a brain-computer interface (BCI) learn to co-adapt with the system through the feedback they receive. Particularly in case of motor imagery BCIs, feedback design can play an important role in the course of motor imagery training. In this paper we investigated the effect of biased visual feedback on performance and motor imagery skills of users during BCI control of a pair of humanlike robotic hands. Although the subject specific classifier, which was set up at the beginning of experiment, detected no significant change in the subjects’ online performance, evaluation of brain activity patterns revealed that subjects’ self-regulation of motor imagery features improved due to a positive bias of feedback. We discuss how this effect could be possibly due to the humanlike design of feedback and occurrence of body ownership illusion. Our findings suggest that in general training protocols for BCIs, realistic feedback design and subject’s self-evaluation of performance can play an important role in the optimization of motor imagery skills.

Keywords: Human-machine interaction, Rehabilitation and assistive robotics
Abstract: Repetitive activities of daily living (ADL) and robotic active training are commonly practised in the rehabilitation of paralyzed patients, both of which have been proven rather effective to recover the locomotor function of impaired limbs. ADL classification based on electroencephalogram (EEG) is of great significance to perform active robotic rehabilitation for patients with complete spinal cord injury (SCI) who lose locomotion of affected limbs absolutely where surface electromyography (sEMG) or active force signal is hardly to be detected. It is however quite a challenge to achieve a satisfying result due to the high randomness of EEG data. A classification method is proposed based on spiking neural networks (SNN) to identify the upper-limb ADL of three classes with 14-channel EEG data. The continuous real-number signals are firstly encoded into spike trains through Ben's Spike Algorithm (BSA). The generated spikes are then submitted into a 3-D brain-mapped SNN reservoir called NeuCube trained by Spike Timing Dependant Plasticity (STDP). Spike trains from all neurons of the trained reservoir are finally classified using one version of dynamic evolving spiking neuron networks (deSNN) - deSNNs. Classifications are presented with and without NeuCube respectively on the same EEG data set. Results indicate the reservoir improves identification accuracy which turns out pretty promising despite that EEG data is highly noisy, low frequently sampled and merely of 14 channels. The classification technique reveals a great potential for the further implementation of active robotic rehabilitation to the sufferers of complete SCI.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: There is a need for increased opportunities for effective neurorehabilitation services for stroke survivors outside the hospital environment. Efforts to develop low-cost robot/computer therapy solutions able to be deployed in home and community rehabilitation settings have been growing. Our long-term goal is to develop a very low-cost system for stroke rehabilitation that can use commercial gaming technology and support rehabilitation with stroke survivors at all functioning levels. This paper reports the results of experiments comparing the old and new TheraDrive systems in terms of ability to assist/resist subjects and the root-mean-square (RMS) trajectory tracking error. Data demonstrate that the new system, in comparison to the original TheraDrive, produces a larger change in normalized trajectory tracking error when assistance/resistance is added to exercises and has the potential to support stroke survivors at all functioning levels.

Keywords: Human-machine interaction, Rehabilitation and assistive robotics
Abstract: Nowadays, There are a lot of tools and pro- cedures for the development of computer applications for teaching, entertainment, telecommunications, marketing, design and other more. This paper present a implementation method for developing applications based on virtual reality and proce- dures physical-haptics, in order to perform rehabilitation tasks, describing the used software tools. The first one is Ogre3D which is used as rendering graphics engine to add realistic 3D visualization features. Then, the physical engine NVIDIA PhysX is used to incorporate accurate physics simulation and to implement collision detection between objects in the virtual environment. The third one is OpenHaptics which is used to generate a force feedback in the haptic device Sensable Phan- tom. Using the developed applications, the user’s immersion sense in the virtual environment is increased and improved, since the user can manipulate virtual objects with realistic physical behaviour. Finally, two examples of implementation in a rehabilitation environment are shown to demonstrate the main features of the developed tool.

Keywords: Human-machine interaction, Wearable assistive and augmenting devices, Biomechatronic and human-centred design
Abstract: When human operators employ robotic lifting aids, haptic feedback about the lifted object is important. In an experimental study we manipulated two factors that influence haptic feedback to the operator: the percentage of compensated weight, and the way the lifted object is held: robocentric (the human hand lifting the robot that holds the object) or anthropocentric (the robot lifting the human who holds the object). We hypothesize that directly holding the object (anthropocentric approach) will improve the realized trajectories when rapidly lifting partly compensated weights. Subjects (n=10) performed a fast semi-repetitive lifting task, lifting a 4kg object to a designated target in either an anthropocentric or robocentric lifting scenario, at different levels (50% - 75% - 95%) of weight compensation. The anthropocentric approach yielded significantly smaller mean over- or under- shoot compared to robocentric lifting, especially for the first trials. The difference increased for higher levels of compensation. We conclude that for fast lifting, the anthropocentric approach better helps subjects to estimate the required forces to move the weight to the target, especially for unexpected movements at high levels of compensation.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Technology Assessment, Ethical and Social Implications of Biorobotics and Biomechatronics
Abstract: Abstract—Stroke impairs individuals to perform activities of daily living. Intense rehabilitation programs offer hope for recovery, but are labor intensive and costly. Robotic rehabilitation technology plays a key role to solve such a problem. Current robotic systems along with brain computer interface (BCI) allow patients to participate in rehabilitation exercises, which require their own mental inputs. Studies have shown such active rehabilitation exercise can induce neuroplasticity and help towards recovery. However, even though BCI-driven robotic systems do exist, they are large complex systems and expensive to set up. These drawbacks limit a wide distribution of these technologies. Currently, the BCI robotic systems only used in large hospitals or research settings, not community level facilities. To facilitate the accessibility of stroke patients to such technologies, we propose a novel BCI-driven exoskeleton rehabilitation system. The exoskeleton has four degrees of freedom (DOF) for assisting the movement of the upper extremities. It is integrated with an affordable and wireless EEG headset for enabling the patients to control the movement of the exoskeleton with their brain activity. The developed exoskeleton is portable and easy to set up. A sequential control scheme is proposed to allow the user to control one movement at a time. An experiment was designed to assess if a healthy individual was able to control the movement of the exoskeleton correctly under a predefined sequence. One volunteer participated in the exploratory study and the volunteer was able to correctly control the exoskeleton in each step.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: In skilled nursing facilities and nursing homes the number of therapists and nurses is insufficient for the number of residents, affecting the quality of rehabilitation and daily care. This study explores the development of an affordable mobile service robot for therapeutic activities in a health center environment where the number of clinicians is insufficient for clinical demand. Using demonstrations and surveys we solicit users’ (clinician and patient) responses to a prototype telepresence robot combined with a NAO humanoid robot trunk to facilitate remote communication between the patient and clinician and to complete supervisory exercising coaching. This paper presents the concept prototype and preliminary survey results of users’ reactions in order to demonstrate its potential activities in their healthcare center.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Biomechatronic and human-centred design
Abstract: This paper proposes a mechanism to derive quantitative descriptions of wheelchair usage as a tool to aid Occupational Therapist with their performance assesment of mobility platform users. This is accomplished by analysing data computed from a standalone sensor package fitted on an wheelchair platform. This work builds upon previous propo- sitions where parameters that could assist in the assessment were recommended to the authors by a qualified occupational therapist (OT). In the current scheme however the task-specific parameters that may provide the most relevant user information for the assessment are automatically revealed through a machine learning approach. Data mining techniques are used to reveal the most informative parameters, and results from three typical classifiers are presented based on learnings from manual labelling of the training data. Trials conducted by healthy volunteers gave classifications with an 81% success rate using a Random Forest classifier, a promising outcome that sets the scene for a potential clinical trial with a larger user pool.

Keywords: Rehabilitation and assistive robotics, Biomechatronic and human-centred design, Human-machine interaction
Abstract: Manual and powered wheelchairs have been widely used as assistive technologies to improve users’ mobility. However, both types of wheelchairs have problems that limit the users’ ability in moving independently, thus impacting social participation, health and quality of life. This paper report on the conceptual development of a manual wheelchair equipped with a servo-controlled power-assisted system. The development process comprised the design of a wheelchair frame properly designed to receive the components of the power-assistance system; the measurement and integrated processing (with an onboard computer) of the user’s forces applied to the handrim and rear wheels angular velocity. The integrated processing of these data generates an order to the motor driver, according to an algorithm of conditions that specifies the state (activation or deactivation) and magnitude of operation of the servo-motor. The output torque of the servo-motor (located below the seat and between the rear wheels) is distributed to both rear wheels via mechanical differential, thus allowing similar drivability to a standard manual wheelchair. The implementation of the innovative and ergonomic characteristics of the servo-controlled power-assisted wheelchair may improve users’ ability to move longer and with comfort and safety, thus benefiting social participation and quality of life.

Keywords: Rehabilitation and assistive robotics, Technology Assessment, Ethical and Social Implications of Biorobotics and Biomechatronics, Human-machine interaction
Abstract: Power wheelchairs have high costs in developing countries, making its access difficult to the physically impaired, its main target audience, and to groups that develop assistive technologies, such as researchers, independent developers and entrepreneurs. Free software and open hardware have been successfully used to bridge access gap in areas where cost was a problem, democratizing the innovation process. This paper presents an open hardware and software platform developed for power wheelchairs, which aims to contribute to research and development in this area and stimulate local industry to implement affordable assistive technologies. We believe this work can be used as model for future research on open electronics platforms.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Prosthetic devices
Abstract: Population ageing calls for innovative solutions to increase daily living autonomy. Since people autonomy relies on their mobility capabilities, several robotized walking aids i.e. walkers and canes, mainly including navigation functions, have been developed. The existing robotized canes generally consist in statically stable mobile platforms equipped with a rod and a handle. This design alters the basic characteristics of original canes i.e. their weight-lightness and compactness. In this paper, a one-wheel telescopic active cane closer to the original cane concept is presented. Its control law and synchronization with the walking cycle is also given along with experimental results.

Keywords: Wearable assistive and augmenting devices, Human-machine interaction, Biomechatronic and human-centred design
Abstract: This paper introduces an approach for enabling visually impaired and blind people to practice jogging activities by 3D environment perception for course detection and collision avoidance, as well as feedback generation in an intuitive manner. Besides a system concept, first prototypic realizations, that confirm the general feasibility, are presented for this domain, which has not been addressed by research until now.

Keywords: Rehabilitation and assistive robotics
Abstract: In the present study we analyze the speed, acceleration, torque, boiler power during a complete phase of human walking and of the change of state: from sitting position to standing position. As a part of the experimentation methodology, we use artificial vision and with this we capture the points located in: hip, knee and ankle, these are states join by segments, to finally obtain the variation of the angle produced by each segment relative to the vertical.

Keywords: Wearable assistive and augmenting devices, Human-machine interaction, Biomechatronic and human-centred design
Abstract: In the present paper an introductory analysis for the knee is make, to determine the physiological qualities, and determinate the degree of freedom and show the most relevant information to be considered to work over the movement of the knee without any injury over the muscles. Is possible to do an analysis to find the maximum forces necessary to be applied whit rehabilitation equipment

Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics, Human-machine interaction
Abstract: In an ageing population many people with muscle weakness may benefit from an assisting exoskeleton to improve their mobility. Recent developments in research labs around the world are often complex, not modular and expensive. This paper introduces a novel modular compliant actuator for use in assistive lower limb exoskeletons. It is a low-cost, light-weight, compliant actuator unit that can be easily mounted on commercially available orthoses. It has the versatility to assist hip-, knee- and ankle flexion/extension individually and/or in sit-tostance or walking activities. An adjustable passive compliance is achieved by a design based on the MACCEPA (Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator) principle. The assisting output torque and the rendered range of compliance are simulated and experimentally demonstrated.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Biomechatronic and human-centred design
Abstract: In recent years, the possibility of using smart technologies to enhance rehabilitative therapies has become a reality. Smart technologies can adjust their functionality based on real-time performance to provide the most effective therapy. This paper presents the design, development and testing of a wearable mechatronic brace created to assist in upper limb rehabilitation. The purpose of the smart brace is to provide safe therapy of musculoskeletal disorders, in particular brachial plexus injuries. A control system has been developed that facilitates the retraining of the biceps for individuals who have suffered brachial plexus nerve damage. Electromyography (EMG) data for flexion and extension of the elbow were recorded from three healthy subjects and used to scale velocity profiles. The experiments assessed the performance of the smart brace in its ability to reproduce a motion, to compensate for the effect of muscle disability and to detect fatigue. The results showed that the control system was able to adjust velocities to accommodate for disability or fatigue. This initial implementation provides a control model and logic from which the brace can be improved. Future testing of the brace using subjects with a brachial plexus injury will help solidify the techniques used for brace control.

Attachments: Video
Keywords: Rehabilitation and assistive robotics
Abstract: PKankle is a robotic device based on a fully-parallel kinematic architecture and specifically designed for the neuro-rehabilitation of the ankle-foot complex. The peculiar kinematics allows the foot support to rotate, with good approximation, about the instantaneous center of rotation of the foot. An adjusting mechanical system allows the device to be employed in different patient positionings. Moreover, it features an integrated load cell for measuring subject interaction forces/torques and a synchronized electromyographic acquisition system to analyze patient's muscular activity. The present work describes kinematic and control aspects specifically addressed to enhance its ergonomics and physiological compatibility to the actual mobility of the ankle-foot complex. Preliminary experimental activities, performed by healthy subjects, have been carried out to assess the effectiveness of the adopted solutions.

Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics
Abstract: In this paper we present the alpha-prototype of the WAKE-up, a wearable robotic device for the rehabilitation of locomotion of pediatric subjects with neurological diseases such as Cerebral Palsy. The WAKE-up is an active knee-ankle orthosis. It is composed of two robotic modules for the rehabilitation of knee and ankle, respectively. Each module can be utilized either alone or together with the other one. The working principle is based on series elastic actuators (SEA), i.e., dc motors equipped with a torsional spring mounted in series to avoid the direct connection of the actuator with the patient’s limb. A SEA permits the control of the force and the emulation of different orthoses with given value of stiffness. The torque transmission is achieved by a timing belt and it is mediated by a torsional spring. The experimental tests conducted on each modules confirmed a good precision of the spring deflection control (position error < 2°) and good overall performances of the force control obtained with the spring stiffness chosen at the design phase.

Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics
Abstract: In this paper, we use modular design method to construct a 4-DoF (Degrees Of Freedom) upper limb exoskeleton. The structure is very simple, and is easy to be modified. Articulation of the exoskeleton is achieved four revolute joints: three for the shoulder and one for the elbow. Static and dynamic models of this exoskeleton are proposed. Experiments and analysis of the exoskeleton robot are carried out to evaluate the effectiveness of the design.

Keywords: Rehabilitation and assistive robotics, Biomechatronic and human-centred design, Neuro-robotics
Abstract: In rehabilitation exoskeletons, alignment of robot and human joints is essential for comfort and performance. Most exoskeletons have their actuators directly at the DOF they control, despite performance being assisted by low move- ment inertias. For our new upper-extremity exoskeleton, we explored using a parallel robot for the auto alignment of the shoulder axes and three serial links to drive the rotations. We hypothesized that weight and inertia can be reduced by relocating the actuators to the non-moving base of the device, as others have done before. To investigate if this is indeed beneficial, we evaluated all possible topologies for placing motors and gearboxes and are here reporting on the best candidates. We explored several drive trains that combine coaxial axes and angular transmissions. As bevel gears show backlash, are high in weight and large in size, three alternative angular transmissions were investigated. After combining the new angular transmissions with the possible topologies and evaluating the 16 resulting combinations, we concluded that for our new, high-performance exoskeleton, the most optimal topology still is one with the motors and gearboxes placed directly at the joint. The hypothesis therefore was disproven for our usage scenarios.

Keywords: Wearable assistive and augmenting devices, Human-machine interaction, Rehabilitation and assistive robotics
Abstract: For an intelligent dynamic motion interaction between a human and a lower-limb exoskeleton, it is necessary to predict the future evolution of the joint gait trajectories and to detect which phase of the gait pattern is currently active. A model of the gait trajectories and of the variations on these trajectories is learned from an example data set. A gait prediction module, based on a statistical latent variable model, is able to predict, in real-time, the future evolution of a joint trajectory, an estimate of the uncertainty on this prediction, the timing along the trajectory and the consistency of the measurements with the learned model. The proposed method is validated using a data set of 54 trials of children walking at three different velocities.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: Stroke is one of the leading causes of disability and advances in neurorehabilitation bring new therapy forms that aim to enhance recovery after stroke. In a multicenter clinical trial, we tested whether robot-assisted therapy of the arm with the therapy robot ARMin is superior to conventional therapy with regard to improvement in arm motor function. In this article, we describe differences in motor function gains among the four participating centers. Three centers showed a tendency favoring robotics whereas one center showed the converse. Results might be accidental considering the small and different number of patients within the centers. However, it indicates that not only study procedures but soft factors that are generally not taken into consideration when planning a multicenter study, such as therapeutic attitude or center differences, might influence the study outcome.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: In adult patients with motor impairments, such as stroke, actuated robots are available to provide an intensive rehabilitation training and to actively assist, enhance and assess neurorehabilitation. However, there is currently no actuated robot available specifically designed for the rehabilitation of children with upper extremity motor impairments. Therefore, ChARMin was designed, an arm exoskeleton robot to assist arm movements for young patients, especially children with cerebral palsy. The first prototype has four degrees of freedom for the shoulder and elbow. The design is based on a serial mechanical structure together with parallel kinematics for remote center of rotation actuation. This approach allows to keep a safe distance between parts of the robot and the patient and it reduces friction, while being highly adaptable to cover the large anthropometric range of the patients aged 5 to 18 years.

Keywords: Human-machine interaction
Abstract: This paper presents Squeeze Me, a squeezable device used to grab attention from the mobile robot Care-O-bot, providing ground for expressive values to be shared between person and robot in a smart environment. Squeeze Me consists of a soft rubbery interactive cover, that can be mounted on a tablet, to enable expression-rich communication. The cover embeds two specifically designed resistive analogue pressure sensors. The expressions exerted on the device by the person are mapped to movements of the robot as well as to an expressive mask displayed on the graphical user interface (GUI) of the tablet that is used to control the robot. This mask shows the robot’s view on the environment as well as its internal states (feelings). A short pinch exercised by the person on the cover results in a sturdy movement of the robot. A hard squeeze results in a quick movement and a gentle touch in a slow approach. All changes in movement are mapped to the modifications in the expressions of the mask, e.g. from neutral to surprise, or joy, depending on the context of interaction. The paper describes the design and implementation of the Squeeze Me prototype, together with a scenario of use in the context of an older person – robot interaction.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Biological systems modeling
Abstract: We are examining whether robust behavioral laws, initially designed to describe sensorimotor control of the upper extremities, can also describe lower extremity movements. Herein, we present our initial results of our research on measuring ankle reaction time (RT). We show that RT measured in ankle dorsiflexion (DP) and inversion-eversion (IE) of 7 healthy young subjects followed a γ distribution, a typical finding in the upper limb response modalities. We propose that the low-order statistics (mean and variance) of the best-fit γ function can be used to concatenate RT across subjects with similar performance and create super-subjects (SS). We then show that the most widely used model of RT cognitive processes, the Ratcliff diffusion model, is adequate to describe ankle RT in an SS. The combination of experimental data analysis with diffusion modeling of ankle RT proposed that at least two cognitive components of RT are accounted for a difference in mean RT observed between DP and IE, namely the speed of information accumulation and the non-decision time that includes, among others, the time for motor response encoding and execution. These results show a great potential to inform our adaptive assist-as-needed robotic therapy delivered to the lower limbs of children with Cerebral Palsy.

Attachments: Video
Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Human-machine interaction
Abstract: In this paper we evaluate ultrasound imaging as a human-machine interface in the context of rehabilitation. Ultrasound imaging can be used to estimate finger forces in real-time with a short and easy calibration procedure. Forces are individually predicted using a transducer fixed on the forearm, which leaves the hand completely free to operate. In this application, a standard ultrasound machine is connected to a virtual-reality environment in which a human operator can play a dynamic harmonium over two octaves, using either finger (including the thumb). The interaction in the virtual environment is managed via a fast collision detection algorithm and a physics engine.

Ten human subjects have been engaged in two games of increasing difficulty. Our experimental results, both objective and subjective, clearly show that both tasks could be accomplished to the required degree of precision and that the subjects underwent a typical learning curve. The learning happened uniformly, irrespective of the required finger, force or note. Such a system could be made portable, and has potential applications as rehabilitation device for amputees and muscle impaired, even at home.

Keywords: Wearable assistive and augmenting devices, Neuroengineering, Biomechatronic and human-centred design
Abstract: A novel instrumentation is proposed to estimate hand and finger movements. Current dataglove systems often measure a reduced set of joint angles and lack a position and orientation measure of the hand with respect to the trunk. Our proposed system, based on inertial and magnetic sensing, is fully ambulatory, light weighted, has a low energy consumption and is therefore suitable to assess kinematics of the hand and fingers in daily life.

Results showed an rms difference of the hand pose with an optical reference system of 16.9+-4.0 mm for the position and 1.5+-0.4 deg for the orientation. Index finger tip positions could be estimated with 5.0+-0.5 mm for flexion extensions movements and 12.4+-3.0 mm for more complex movements in which both flexion-extension and abduction-adduction movements were involved.

Keywords: Rehabilitation and assistive robotics
Abstract: The functional evaluation of the upper-limb can be clinically assessed through the analysis of the kinematics, the dynamics, and measures of motor control. Such measures are usually obtained in a clinical environment with commercial stereoscopic 3D devices that allow to sample kinematics at high frequency, and with high accuracy and precision, but that are, on the other hand, expensive, time consuming, and, most of all, are not portable. Consequently, such assessments are available only in clinics. With the aim of developing applications for neurological patients movement analysis in home environment, an experimental study has been conducted to compare the performances of a passive-marker motion capture system with the Kinect. Data were acquired simultaneously with the two systems during reaching against gravity movements. Results suggest that Kinect may be a valid tool for studying reaching against gravity and assessing upper-limb functionality at home in neurological patients.

Keywords: Rehabilitation and assistive robotics
Abstract: In this paper, we present an initial attempt to apply Knowledge Discovery techniques over real performance data from patients enrolled in robotic therapy in order to explore how to better optimize therapy. Performance data sets encompass measurements such as position, velocity and force, as well as final performance measures. We apply the Principal Component Analysis method in an attempt to reduce the dimensionality of the problem, molding subsets that were the input into a Multilayer Perceptron Artificial Neural Network which would carry out data mining with the purpose of discovering the relative significance of each field, in relation to a performance measure. It was possible to notice the impact caused by the lack of each field in terms of specific performance measures, indicating which data are more relevant to use in further experiments.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Biomechatronic and human-centred design
Abstract: This paper presents the design of the socially assistive companion robotic wheelchair named RoboChair. Unlike in most current companion robotics projects, the approach of RoboChair is not to build a completely new robotic device. Instead, the focus of the RoboChair project is to convert an already useful device (i.e. wheelchair) to a socially assistive companion robot. The authors argue that there are number of advantages in this approach. The proposed robotic chair is a mobile robot that can carry a person. It is equipped with several measuring devices for measuring vital signs. The robot chair is capable of engaging users with interactive dialogs through a touch screen and by using human-robot interaction techniques. It has a scalable modular software architecture so that adding new hardware and software modules is straightforward. The software framework is based on Robot Operating System (ROS) open source robotic middleware.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Wearable assistive and augmenting devices
Abstract: Systems based on Surface Electromyography (sEMG) signals require some form of machine learning algorithm for recognition and classification of specific patterns of muscle activity. These algorithms vary in terms of the number of signals, feature selection, and the classification algorithm used. In our previous work, a technique for recognizing muscle patterns using a single sEMG signal, called Guided Under-determined Source Signal Separation (GUSSS), was introduced. This technique relied on a very small number of features to achieve good classification accuracies for a small number of gestures. In this paper, an enhanced version called Hierarchical GUSSS (HiGUSSS) was developed to allow for the classification of a large number of hand gestures while preserving a high classification accuracy.

Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics
Abstract: Robotics for rehabilitation and human amplification is imminent to become part of our daily life. The juxtaposition of human control capability and machine mechanical power offers a promising solution for human assistance and force enhancement. This paper presents an alternative and simple exoskeleton Human-Machine Interface (HMI) for human strength and endurance amplification using a modified version of the Hill-type muscle. Pneumatic Artificial Muscles (PAM) are used as actuators for its high power-to-weight ratio. Genetic Algorithms (GA) approach locally optimizes the control model parameters for the assistive device using muscle surface electromyography (sEMG). The proposed methodology offers advantages such as: reducing the number of electrodes needed to monitor the muscles, decreases the real-time processing effort, which is necessary for embedded implementation and portability, and brings the HMI to a neural level.

Keywords: Human-machine interaction, Rehabilitation and assistive robotics, Wearable assistive and augmenting devices
Abstract: Abstract— In the field of robotic rehabilitation, surface electromyography (sEMG) has been proposed for controlling exoskeleton device for assisting different movements of the human joints, such as the shoulder, the elbow, the wrist and the fingers. However, few works have been proposed for using sEMG to control a forearm exoskeleton for assisting the movement of pronation and supination. The main difficulty for employing the sEMG control approach is the low signal to noise ratio of the pronator and supinator muscle group. To overcome this difficulty, we propose an alternative method utilizing force myography (FMG) instead of the sEMG for controlling a forearm pronation/supination exoskeleton. An easy setup strap with an array of force sensors was developed to capture the forearm FMG signal. The FMG signal was processed and classified using the state-of-art machine learning algorithm - Extreme Learning Machine (ELM) to predict the forearm position. The prediction results can be used to control a forearm pronation/supination exoskeleton. A bilateral experiment with two protocols was designed to demonstrate one of the potential applications of the proposed system, as well as to evaluate the system performance in terms of classification accuracy. One volunteer participated in the experiment. The result shows the system was able to predict the position of the forearm using the proposed method with 98.36% and 96.19% of accuracy.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: Contributions of muscle forces in isometric and normal (movement) reaching have not been thoroughly compared. In this study, we ask if position-based and velocity-based cursor mappings during planar isometric reaching produce muscle forces that are similar to those exerted during unassisted movement. Healthy subjects pushed against a static manipulandum handle to direct a cursor toward a target using either a position or velocity mapping. Applied force and cursor path data were used to create dynamic musculoskeletal simulations (using the OpenSim platform) of targeted isometric and movement reaches. Isometric muscle forces in both position and velocity mappings were found to be distinct from the corresponding forces in movement simulations. These results motivate future research on the design of a physiology-based isometric mapping that incorporates arm dynamics and inertia. A mapping that produces comparable muscular activity in isometric and movement reaching may support the development of improved isometric and robotic rehabilitation strategies for patients with upper limb movement deficits.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Human-machine interaction
Abstract: In rehabilitation robotics, surface electromyography (sEMG) is extensively used as a human-machine interface, mainly for prosthetic/orthotic control purposes. The technique has been proved to be a highly accurate way of detecting a human subject's intended position, force and torque configurations. Widely applied in the clinics, it is gaining even more momentum as polyarticulated, ever-more dexterous self-powered rehabilitation artifacts appear on the market.

In this paper we present a preliminary result about the usage of the same technique to estimate a human subject's hand stiffness in the presence of force-feedback. Six intact subjects were immersed in a simple teleoperation task, in which force feedback was present; the hand stiffness was measured via force perturbation at the master's manipulandum and associated with the sEMG signals. This live estimation of stiffness was then used to control the impedance of the slave. Experimental results show that this system leads to high positional precision but high contact forces when the estimated stiffness is high, and vice-versa.

The system has potential applications in impedance control of rehabilitation devices such as, e.g., upper / lower limb prostheses, self-powered orthoses and exoskeleta, leading to an ever-better integration with patients.

Keywords: Biological systems modeling
Abstract: The synaptic input to the motoneurons cannot be measured in humans due to ethical and technical difficulties. For these reasons realistic computational models of a motoneuron pool and the innervated muscle fibers (a ``motor unit pool'') have an important role in the study of the human control of muscles. However such models are complex and their mathematical analysis is difficult. We present a system identification approach of a realistic motor unit pool model with the objective of obtaining a simpler model capable of representing the transduction of the motoneuron pool inputs into the force generated by the respective muscle. The system identification was based on an orthogonal least squares algorithm to find a NARMAX model, the input being the net dendritic excitatory synaptic conductance of the motoneurons and the output being the force produced by the muscle. The identified model output reproduced the mean behavior of the output from the realistic computational model even for input-output signals not used in the identification process, such as sinusoidally modulated output force signals.

Keywords: Biological systems modeling, Wearable assistive and augmenting devices, Rehabilitation and assistive robotics
Abstract: There are many motor control aspects that must be taken into account for the design and applications of rehabilitation robots and exoskeletons. In this respect the outcomes from behavioral motor control studies can provide relevant design criteria. In this context, to verify the level of motor learning and adaptation under the influence of mechanical perturbations, we used a coincident timing task. The task consisted of hitting with the hand a virtual target falling on the screen. The movement was performed in the horizontal plane and consisted of an elbow flexion to reach the real marker on a table. Sixteen volunteers were divided into two groups: 1 – task without perturbation on the hand and, 2 - task with a predictable mechanical perturbation on the hand. Data were analyzed by the percentage of correct responses and the tendency of the correct responses. In order to assess the duration as well as the velocity and acceleration of the movement, inertial sensors were used. The results showed a task performance improvement for group 2 when compared to group 1. Furthermore, group 1 showed a trend to delay on correct responses, while the trend in group 2 was to anticipate on correct responses. These results indicate that a predictable mechanical perturbation during learning this coincident timing task can improve the motor learning process and paves the way to further experiments with the use of an upper limb exoskeleton.

Keywords: Biological systems modeling, Neuroengineering, Locomotion and manipulation in robots and biological systems
Abstract: Based on the idea of synergy to explore the building blocks of movements, this study focused on the muscle space for reaching movements by human upper limbs on a horizontal plane to estimate the relationship among muscle synergies, equilibrium-point (EP) trajectories, and endpoint stiffness in two ways: (1) a novel estimation method that analyze electromyographic signals under the concept of agonist- antagonist (A-A) muscle pairs and (2) a conventional estimation method that uses mechanical perturbations. The experimental results suggest that (1) muscle activities of reaching movements by human upper limbs are represented by only three functional muscle synergies; (2) each muscle synergy balances the coactivations of A-A muscle pairs; (3) two of the muscle synergies are invariant bases that form an EP trajectory described in polar coordinates centered on a shoulder joint, where one is a composite unit for radial movement and the other is for angular movement; and (4) the third muscle synergy is the invariant basis for additional adjustment of the endpoint stiffness and has some influence on the direction and size of the endpoint stiffness ellipse.

Keywords: Biological systems modeling, Locomotion and manipulation in robots and biological systems
Abstract: Human standing is characterized by large body sway, which cannot be explained by linear control. In past researches, sway has been considered as an uncontrolled biological noise. In contrast, we consider the sway to be a cyclic motion generated by continuous proportional-integral-derivative (PID) control with weak nonlinearlity. Through mathematical analysis of nonliner PID control, cyclic motion is shown to be generated by a stability-gain dependent Hopf bifurcation, and biological noise is shown to help the smooth transition between stationary stable state and cyclic state. The relevance of the proposed sway generation mechanism is verified through human experiment on floors with different stability. As a result, the existence of Hopf bifurcation, i.e., apparent expansion of sway with small decrease of control parameters, realized by the destabilization of floor, is observed.

Keywords: Locomotion and manipulation in robots and biological systems, Human-machine interaction, Prosthetic devices
Abstract: The force measurement system unavoidably introduces noise in the output signals. The noise in the center of pressure (COP) signal is the propagation noise arise from the combination of the components used to compute it. A framework to analyze the random error in COP signals was introduced based on the ``Guide to the Expression of Uncertainty of Measurement'' (GUM) approach. Furthermore, the spatiotemporal resolution criterion was used as a parameter to evaluate force measurements systems under specific experimental conditions.

Attachments: Video
Keywords: Wearable assistive and augmenting devices, Human-machine interaction
Abstract: In this paper we propose to drive an actuated orthosis using an adaptive controller based on a reference model. It is not necessary to know all the functions of the dynamic model. Needing only the global structure of the dynamic model, we use a specific adaptive controller to obtain good performance in terms of trajectory tracking both in position and in velocity. A Multi-Layer Perceptron Neural Network (MLPNN) is used to estimate dynamics related to inertia, gravitational and frictional forces along with other unmodeled dynamics. The Lyapunov formalism is used for stability study of the system (shank+orthosis) in closed loop and to determine adaptation laws of the neural parameters. To treat the non-linearties related to the MLPNN, we have used first order Taylor series expansion. Experimental results have been obtained using a real orthosis worn by an appropriate dummy. Several tests have been realized to verify the effectiveness and the robustness of the proposed controller. For instance, our proposed orthosis model has given robust tracking performance under assistive as well as resistive forces.

Attachments: Video
Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics, Human-machine interaction
Abstract: The authors present in this paper a robust torque control of an active orthosis designed to assist in flexion/extension of the knee joint during physical therapy. The orthosis is driven by a rotary Series Elastic Actuator presented in authors' previous paper. The adopted control strategy is based on H-infinity criterion in order to ensure good system performance even when it is subjected to parametric uncertainties and external disturbances. The controller performance is evaluated through the frequency response function analysis. Experimental results involving the interaction between a subject and the active knee orthosis are also presented to show the performance of the developed prototype.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Neuro-robotics
Abstract: Cerebrovascular accident or stroke is one of the major brain impairments that affects numerous people globally. After a unilateral stroke, sensory motor damages contralateral to the brain lesion occur in many patients. As a result, gait remains impaired and asymmetric. This paper describes and simulates a novel closed loop algorithm designed for the control of a lower limb exoskeleton for post-stroke rehabilitation. The algorithm has been developed to control a lower limb exoskeleton including actuators for the hip and knee joints, and feedback sensors for the measure of joint angular excursions. It has been designed to control and correct the gait cycle of the affected leg using kinematics information from the unaffected one. In particular, a probabilistic particle filter like algorithm has been used at the top-level control to modulate gait velocity and the joint angular excursions. Simulation results show that the algorithm is able to correct and control velocity of the affected side restoring phase synchronization between the legs.

Attachments: Video
Keywords: Rehabilitation and assistive robotics, Biological systems modeling, Locomotion and manipulation in robots and biological systems
Abstract: Individuals with stroke often have diminished muscle strength that contributes to impaired push-off propulsion during walking, resulting in abnormal compensatory mechanisms and slower gait speeds. In this paper, we present a sagittal, 2-link biomechanical model of ankle push-off propulsion dynamics. The purpose of the model is to predict the parameters of an impedance controller to generate a desired level of anterior-posterior push-off during assisted walking with a modular ankle robot (“Anklebot”). In conjunction with our development of a novel gait event-triggered training approach, this model will facilitate tailoring the assisted push-off to individual severity. Here, we develop the model from first principles and experimentally validate it in a healthy subject.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Human-machine interaction
Abstract: This paper deals with adaptive impedance control for ankle rehabilitation based on the assist-as-needed paradigm. Two robot assistance control strategies are evaluated, where the first one considers a complementary robot's stiffness based on the estimate of the patient's stiffness, and the second one considers an optimal solution that minimizes a cost function relating the rehabilitation goal and the interaction between patient and robot. Also, the robot level of assistance is adapted based on the performance of the patient playing a computational game. The proposed control strategies are evaluated regarding the rehabilitation robot Anklebot and an interactive environment where the game runs. Preliminary experimental results, obtained with one impaired patient, confirm the feasibility of the proposed control solutions on helping the subjects to finishing the tasks with optimal assistance from robot.

Keywords: Rehabilitation and assistive robotics, Biological systems modeling, Human-machine interaction
Abstract: Sit-to-stand (STS) transfers are a common human task which involves very complex sensorimotor processes to control the highly nonlinear musculoskeletal system. In this paper, typical unassisted and assisted human STS transfers are formulated as optimal feedback control problem that finds a compromise between task end-point accuracy, human balance, jerk, effort, and torque change and takes further human biomechanical control constraints into account. Differential dynamic programming is employed, which allows taking the full, nonlinear human dynamics into consideration. The biomechanical dynamics of the human is modeled by a six link rigid body including leg, trunk and arm segments. Accuracy of the proposed modelling approach is evaluated for different human healthy subjects by comparing simulations and experimentally collected data. Acceptable model accuracy is achieved with a generic set of constant weights that prioritize the different criteria. The proposed STS model is finally used to determine optimal assistive strategies to be performed by a robotic mobility assistant suitable for either a person with specific body segment weakness or a more general weakness.

Attachments: Video
Keywords: Rehabilitation and assistive robotics, Neuroengineering, Human-machine interaction
Abstract: A novel concept of rehabilitation is proposed for the recovery of walking post-stroke made possible by a novel piece of robotic hardware, the MIT Skywalker-γ prototype. Rather than prescribing motion for the patient similar to most current rehabilitation robots, we built an environment to foster self-directed movement. The concept is based upon our working model on dynamic motor primitives, prior rehabilitation results and a survey of common gait pathologies associated with stroke. Skywalker-γ was carefully developed to provide an environment in which three motor primitives can be trained in isolation or in combination to further insights into both rehabilitation and human motor control.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: This paper presents the design and control of a novel assistive system, FEXO Knee, which combines functional electrical stimulation (FES) with a compliant exoskeleton for better physical rehabilitation of knee joint. The knee exoskeleton and FES work in a synergetic manner that attempts to allow arbitrary torque allocation via regulating a tunable gain. The study focuses on controlling human rhythmic movements, i.e., the swing of shank, to demonstrate the assistance efficiency of the hybrid FES-exoskeleton rehabilitation. Two muscle groups (Vasti and Hamstrings) were stimulated to produce active torque for knee joint. The reference trajectories of the exoskeleton and FES were provided by central pattern generator that acts as a phase predictor to deal with unexpected phase confliction between human shank and exoskeleton. The modulated pulse width of FES stimulator is controlled by a model-based feed-forward controller. The elastic cable-driven actuator of knee exoskeleton allows safe interaction with the patients and avoids abruptly large torque shocks, which is more important than pure position tracking in robotic-assisted rehabilitation. The motion of the knee exoskeleton was controlled by a proportional-integral-derivative controller. The joint angle is the only feedback signal that needs to be measured in the control frame. The mutual torque was also measured during the swing but it is merely for the purpose of performance evaluation. Four healthy subjects participated in the initial evaluation experiments and the results showed good performance of the hybrid FES-exoskeleton system.

Keywords: Wearable assistive and augmenting devices, Locomotion and manipulation in robots and biological systems, Rehabilitation and assistive robotics
Abstract: The target of this work is to experimentally validate the Second Spine, a wearable device recently developed by our group to transfer forces from shoulder to pelvis during loaded walking. A key-feature of the Second Spine compared to traditional framed backpacks is the adjustable stiffness of its structure, which allows the wearer to change the loadbearing behavior of the device. In line with previous studies on loaded walking, we investigate biomechanical and physiological variables on a small group of young healthy subjects, as they walked on a treadmill under 3 different conditions: free walking, walking with a backpack of 25% of subject’s Body Weight (BW), and walking with the same backpack while wearing the device. Results indicate that wearing the Second Spine significantly reduces the pressure on shoulders and induces smaller deviations from unloaded walking in terms of gait timing and stride length. The activations of the rectus femoris and the gastrocnemius muscles, along with the kinematics of the knee joint, provide indirect evidence that dynamic loadswere rigidly transmitted from the shoulder to the waist. We discuss how these preliminary findings might be relevant for the prevention of injuries related to load carriage, and how they set important guidelines for the next generation of the Second Spine.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices, Human-machine interaction
Abstract: In this paper, the lower limb exoskeleton uses a harmonic drive actuator and two pneumatic artificial muscles (PAMs). This hybrid actuation takes both advantages of harmonic drive and PAM. It provide high accuracy position control and compliant behavior. The disadvantages of each type of actuator are overcome. This exoskeleton is suitable for the strength augmentation of human lower limbs, such as the gait rehabilitation routine of hip and knee joints.

Keywords: Rehabilitation and assistive robotics, Locomotion and manipulation in robots and biological systems
Abstract: Nowadays, an increasing number of people with stroke are suffering considerably from a loss of physical mobility. Various traditional interventions have been developed to restore survivors’ normal motor function following a stroke, but their effects are considerably limited. Many of these techniques require physical therapist’s observation, specifically designed preparatory exercises and direct control of the lower limbs’ position. Therefore, we propose a novel automatic gait training system for gait rehabilitation of hemiparetic patients. It integrates a split belt treadmill with a functional electrical stimulation (FES) device, which is used to improve gait quality by delivering electrical stimuli to the muscles. The delivery of the stimulus from the FES device is triggered automatically during gait cycle. As subjects walk on the separated treadmill, the gait phases are estimated by an algorithm that observes variation in the current values of the treadmill motors. Finally, we have preliminarily tested the feasibility of the proposed method through experiments on simulated hemiparetic subjects, by comparing with experimental results using force plates.

Keywords: Wearable assistive and augmenting devices, Rehabilitation and assistive robotics
Abstract: In recent years, various robots have been developed that can be worn on the body. These can be used to assist elderly people and people with disabilities by either providing extra power or helping them with walking. These robots usually form an external skeleton around the frame of the body. Although the external skeletal structure has the advantage of supporting the robotic mechanism, an adjustment mechanism to match it to the contours of the wearer’s body is necessary, and this mechanism increases the weight of the robot. In this study, we propose a non-exoskeletal structure which uses the skeletal system of the human body, and we develop a lightweight robotic wear that gives little feeling of restriction.

Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis
Abstract: This paper proposes a control scheme for handling surgical instruments by a single port access surgery robotic platform. This scheme is based on a Hidden Markov Model for detecting interaction with tissue inside the abdomen and a Kalman filter measurement fusion method for estimating the fulcrum point using forces and torques exerted on several instruments. In order to perform movements taking into account the estimated fulcrum point, a parallel force-position control algorithm is proposed in order to minimize exerted forces in the patient’s abdomen. At last, proposed control scheme has been implemented in a surgical robotics platform composed by two manipulators and experimental results are shown in order to demonstrate how it works.

Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis, Prosthetic devices
Abstract: Accurate three dimensional scanning of surfaces, especially on humans, is more and more relevant. The usage of laser projection systems is widespread. However, a medical certification Class I, high accuracy, a flexible and not static handling as well as the ability to record from more than one direction has never been combined in a single device. Our project aims at the ideal setting for an easy to use, flexible scanning method from more than one recording direction for human tissue without a need of protective equipment. A minimum of requirements for the user and the system itself, as well a possible certification as medical product shall be implemented using a high accurate NDI stereo camera. Interactions and influences of the considered laser modules and reflectors on/with the camera were examined. In this paper, we present, to the authors’ best knowledge, novel results of an ideal parameter setting and the requirements based on an 850nm laser module and human tissue for possible applications in navigated surgery or individualized prosthetics.

Keywords: Technology for assisted surgery and diagnosis
Abstract: This work wants to investigate the efficacy of a vibro-tactile feedback to convey a haptic perception to the surgeon in a teleoperated robotic system for surgery. To this purpose, vibrotactile actuators have been embedded in the end effector of the master interface of a tele-operated robotic system made of the haptic joystick Novint Falcon and the Kuka Light Weight Robot III. Vibrotactile feedback can be used to support the surgeon during the surgical procedure, guiding him/her during the intervention, and to train unskilled surgeons with simulators. The development and the experimental validation of the master interface with the vibrotactile feedback is presented in this paper. The system has been validated on 12 subjects, who were requested to control the movement of a sphere along a desired path in a virtual environment. Results have been compared with the three cases of absence of feedback, visual feedback and combined vibrotactile and visual feedback. The obtained results demonstrate that a vibrotactile feedback can improve in a statistically significant manner the accuracy of the procedure with respect to the absence of feedback.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Surgical navigation and robotics, Image and model-guided interventions
Abstract: This paper presents the virtual fixture control methods for a hybrid parallel-serial micromanipulator, which is designed for assisting ophthalmic surgeons. Virtual fixtures are features of surgical robotic setups to improve quality of the surgery and reduces the operation risk. In the domain of ophthalmic surgery lack of virtual fixtures in manual operations has limited, and sometimes even blocked, the treatment options. The contribution of this paper is concept analysis and implementation of flexible virtual fixture for the novel hybrid parallel-serial mechanism and experimentally evaluation of this concept. The virtual fixture using this mechanism enables the user to adjust them even during the procedure. Pivoting around a Remote Center of Motion (RCM), which in retinal surgery is the incision point, is the most famous virtual fixture of ophthalmic surgery. Autonomous RCM adjustment for Vitreo-Retinal surgery, implying retinal reachability study, is the secondary contribution which is investigated in this paper.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Human-machine interaction, Surgical navigation and robotics
Abstract: This paper presents a cognitive architecture for a camera robotic assistant aimed at providing the proper camera view of the operating area in an autonomous way. The robotic system is composed of a miniature camera robot and an external robot. The camera robot is introduced into the abdominal cavity and handled by the external robot through magnetic interaction. The cognitive architecture is provided with a long-term memory, which stores surgical knowledge, behaviors of the camera and learning mechanisms, and a short-term memory that recognizes the actual state of the task and triggers the corresponding camera behavior. To provide the proper camera view, each state of the task is characterized by a Focus of Attention (FOA), defined by an object, a position of the object in the image, and a zoom factor. The architecture also includes a learning mechanism to take into account particular preferences of surgeons concerning the viewpoint of the scene. The architecture proposed is validated through a set of in-vitro experiments.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Surgical navigation and robotics
Abstract: Nowadays, robotic-assisted surgery does not allow beating heart surgery with autonomous motion compensation functionalities. This paper tackles this problem, based on a robotic control architecture that relies on force feedback. The algorithm merges two cascade loops. The inner one is based on the Kalman active observer (AOB), performing model-reference adaptive control to impose a well-defined stable plant. The outer one, based on a model predictive control (MPC) approach, generates control references for beating heart motion compensation. Two robots are used in the experiments. A lightweight 4-DoF surgical robot generates desired surgical forces and a 3-DoF robot equipped with an ex vivo heart at the end-effector reproduces realistic heart motion. Additionally, robustness to cardiac stiffness mismatches is analyzed.