With this thesis, I would like to lay the foundations for designing human interfacing wearable exoskeleton robots that are truly designed for the human. Before starting the development of the first human arm exoskeleton prototype, tasked to telemanipulate a space robot, I extensively searched for prior art in databases to potentially find guidelines on how to design a wearable robotic exoskeleton. Information was very scarce, however, and I found only a handful of information at all. Previous records have either shown device concepts only, incomplete devices or devices built to interact with only a sub-set of joints of the human arm. No record has provided evidence of a successful robot control with a portable exoskeleton, let alone with force-feedback to the operator. Not even to speak of finding quantitative analyses about the goodness of physical human–robot interaction or about bilateral control performance with such exoskeletons. Most of the reference material rather raised new questions than providing answers to me. I noticed that previous exoskeleton devices had been designed similar to typical robotic manipulators, but aiming to encapsulate the human limb. This was done despite the fact that artificial robotic systems are fundamentally different in structure from biological human limbs. Moreover, all prior exoskeletons had been developed with anthropometric data of specific indivi-duals. This seemed like a wrong approach to me and inspired me to investigate how these fundamental differences between robots and humans can be harmonized. I was motivated to start this scientific research about finding the fundamentals of ergonomic exoskeleton design. Now, a couple of years later, I can present with this thesis a novel quantitative analysis approach for assessing combined physical human–exoskeleton interaction. The theory presented allows the design analysis and evaluation of exoskeletons, and the solutions provided offer a clear set of design guidelines helpful to the community in the future. The guidelines show, on scientific grounds, how to best conceive exoskeleton kinematics, motorization and mechanical structures for enabling smooth and comfortable physical human robot interaction with portable exoskeletons. Technological solutions are proposed as well, that allow conceiving of lightweight exoskeletons with little apparent inertia and good force-feedback performance for robotic telemanipulation. The feasibility of developing a portable and body-grounded exoskeleton for the entire human arm is shown for the first time. It is proven that the device can interact seamlessly with natural motion of the human arm, without variation of its mechanical structure, for different operators. A new paradigm for the design of kinematic exoskeleton structures is developed, as well as a novel actuator concept, based on Bowden Cable transmissions. The results presented in this thesis provide the lacking theoretical fundament and the technological solutions, which together enable the design of physically interacting human–robot systems that are truly conceived for the human.

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Background: It has been shown that intense training can significantly improve post-stroke upperlimb functionality. However, opportunities for stroke survivors to practice rehabilitation exercises can be limited because of the finite availability of therapists and equipment. This paper presents a haptic-enabled exercise platform intended to assist therapists and mo-derate-level stroke survivors perform upper-limb reaching motion therapy. This work extends on existing knowledge by presenting: 1) an anthropometrically-inspired design that maximizes elbow and shoulder range of motions during exercise; 2) an unobtrusive upper body postural sensing system; and 3) a vibratory elbow stimulation device to encourage muscle movement. Methods: A multi-disciplinary team of professionals were involved in identifying the rehabilitation needs of stroke survivors incorporating these into a proto-type device. The prototype system consisted of an exercise device, postural sensors, and a elbow stimula- tion to encourage the reaching movement. Eight experienced physical and occupational therapists partici-pated in a pilot study exploring the usability of the prototype. Each therapist attended two sessions of one hour each to test and evaluate the proposed system. Feedback about the device was obtained through an administered questionnaire and combined with quantitative data. Results: Seven of the nine questions regar-ding the haptic exercise device scored higher than 3.0 (somewhat good) out of 4.0 (good). The postural sensors detected 93 of 96 (97%) therapistsimulated abnormal postures and correctly ignored 90 of 96 (94%) of normal postures. The elbow stimulation device had a score lower than 2.5 (neutral) for all as-pects that were surveyed, however the therapists felt the rehabilitation system was sufficient for use without the elbow stimulation device. Conclusion: All eight therapists felt the exercise platform could be a good tool to use in upperlimb rehabilitation as the prototype was considered to be generally well de-signed and capable of delivering reaching task therapy. The next stage of this project is to proceed to clinical trials with stroke patients.

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In this paper, a new biomimetic tendon-driven actuation system for prosthetic and wearable robotic hand applications is presented. It is based on the combination of compliant tendon cables and one-way shape memory alloy (SMA) wires that form a set of agonist–antagonist artificial muscle pairs for the required flexion/extension or abduction/adduction of the finger joints. The performance of the proposed actuation system is demonstrated using a 4 degree-of-freedom (three active and one passive) artificial finger testbed, also developed based on a biomimetic design approach. A microcontroller-based pulse-width-modulated proportionalderivation (PWM-PD) feedback controller and a minimum jerk trajectory feedforward controller are implemented and tested in an ad hoc fashion to evaluate the performance of the finger system in emulating natural joint motions. Part II describes the dynamic modeling of the above nonlinear system, and the model-based controller design.

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Ananthropomorphic underactuated prosthetic hand, endowed with position and force sensors and controlled by means of myoelectric commands, is used to perform experiments of hier-archical shared control. Three different hierarchical control strategies combined with a vibrotactile feedback system have been developed and tested by able-bodied subjects through grasping tasks used in activities of daily living (ADLs). The first goal is to find a good tradeoff between good grasping capabilities and low attention required by the user to complete grasping tasks,without addressing advanced algorithm for electromyographic processing. The second goal is to understand whether a vibrotactile feedback system is subjectively or objectively useful and how it changes users’ performance. Experiments showed that users were able to successfully operate the device in the three control strategies, and that the grasp success increased with more interactive control. Practice has proven that when too much effort is required, subjects do not do their best, preferring, instead, a less-interactive control strategy. Moreover, the experiments showed that when grasping tasks are performed under visual control, the enhanced proprioception offered by a vibrotactile system is practically not exploited. Nevertheless, in subjective opinion, feedback seems to be quite important.

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The prevalence of neurological disorders such as stroke, spinal cord injury and traumatic brain injury is increasing quickly in the industrialised societies. Although the benefit of the use of technology in rehabilitation and neurorehabilitation programs is proved, the presence of mechatronic systems is still very low. This paper proposes a new lower limb exoskeleton for functional rehabilitation in persons with neurological pathologies. Since potential users have very reduced mobility even to start common daily movements, the control of the exoskeleton has to be intention based The estimation of the intention of the user is based on hip and knee angle, and the EMG signal is monitored for intention detection, control and neurofeedback aims. A novel approach of a whole mechatronic system has been done in order to approach functional rehabilitation in patients with neurological disorders and stroke. The EMG to force conversion in paraplegic patients is also described.

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