Interference estimated time of arrival on a 6-DOF cable-driven haptic foot platform

A Cable-Driven Locomotion Interface employs two independent cable-driven haptic foot platforms constrained in six degrees of freedom (6-DOF). Its control system and its geometry are designed for performing a wide range of trajectories that could generate cable interferences. This paper presents and analyzes computational methods for determining which cable can be released from an active actuation state while allowing control in a minimal tension state, thereby ensuring that both platforms stay in a controllable workspace. One challaging task is to develop light and fast computational algorithms for hard real time processes included in haptic display applications. Seeing that releasing a cable from an active actuation state might generate discontinuities in tension values in the other cables, this paper proposes collision prediction schemes named Interference Estimated Time of Arrival in order to reduce or completely eliminate such discontinuities

Cable interference control in physical interaction for cable-driven parallel mechanisms

Cable interferences and collisions can lead to unpredictable behavior when a human physically interacts with a cable-driven parallel mechanism through its mobile platform. This paper presents an interactive control approach to prevent two cables in interference from folding onto one another, and thus preserve the cable-mechanism geometry. In this approach, the controller generates a repulsive force to prevent the cables from crossing. Therefore, the task is executed within the cable-driven parallel mechanism’s geometric limits. The repulsive force applied by the controller is derived from the gradient of the minimum distance between any pair of cables of the parallel mechanism. In turn, this minimum distance between cables is computed from the Karush-Kuhn-Tucker conditions of the associated optimization problem. The approach was tested and validated on a parallel mechanism driven by seven cables

Reconfigurable cable driven parallel mechanism

Due to the fast growth in industry and in order to reduce manufacturing budget, increase the quality of products and increase the accuracy of manufactured products in addition to assure the safety of workers, people relied on mechanisms for such purposes. Recently, cable driven parallel mechanisms (CDPMs) have attracted much attention due to their many advantages over conventional parallel mechanisms, such as the significantly large workspace and the dynamics capacity. In addition, it has lower mass compared to other parallel mechanisms because of its negligible mass cables compared to the rigid links. In many applications it is required that human interact with machines and robots to achieve tasks precisely and accurately. Therefore, a new domain of scientific research has been introduced, that is human robot interaction, where operators can share the same workspace with robots and machines such as cable driven mechanisms. One of the main requirements due to this interaction that robots should respond to human actions in accurate, harmless way. In addition, the trajectory of the end effector is coming now from the operator and it is very essential that the initial trajectory is kept unchanged to perform tasks such assembly, operating or pick and place while avoiding the cables to interfere with each other or collide with the operator. Accordingly, many issues have been raised such as control, vibrations and stability due the contact between human and robot. Also, one of the most important issues is to guarantee collision free space (to avoid collision between cables and operator and to avoid collisions between cables itself). The aim of this research project is to model, design, analysis and implement reconfigurable six degrees of freedom parallel mechanism driven by eight cables. The main contribution of this work will be as follow. First, develop a nonlinear model and solve the forward and inverse kinematics issue of a fully constrained CDPM given that the attachment points on the rails are moving vertically (conventional cable driven mechanisms have fixed attachment points on the rails) while controlling the cable lengths. Second, the new idea of reconfiguration is then used to avoid interference between cables and between cables and operator limbs in real time by moving one cable’s attachment point on the frame to increase the shortest distance between them while keeping the trajectory of the end effector unchanged. Third, the new proposed approach was tested by creating a simulated intended cable-cable and cable-human interference trajectory, hence detecting and avoiding cable-cable and cable-human collision using the proposed real time reconfiguration while maintaining the initial end effector trajectory. Fourth, study the effect of relocating the attachment points on the constant-orientation wrench feasible workspace of the CDPM. En raison de la croissance de la demande de produits personnalisés et de la nécessité de réduire les coûts de fabrication tout en augmentant la qualité des produits et en augmentant la personnalisation des produits fabriqués en plus d'assurer la sécurité des travailleurs, les concepteurs se sont appuyés sur des mécanismes robotiques afin d’atteindre ces objectifs. Récemment, les mécanismes parallèles entraînés par câble (MPEC) ont attiré beaucoup d'attention en raison de leurs nombreux avantages par rapport aux mécanismes parallèles conventionnels, tels que l'espace de travail considérablement grand et la capacité dynamique. De plus, ce mécanisme a une masse plus faible par rapport à d'autres mécanismes parallèles en raison de ses câbles de masse négligeable comparativement aux liens rigides. Dans de nombreuses applications, il est nécessaire que l’humain interagisse avec les machines et les robots pour réaliser des tâches avec précision et rapidité. Par conséquent, un nouveau domaine de recherche scientifique a été introduit, à savoir l'interaction humain-robot, où les opérateurs peuvent partager le même espace de travail avec des robots et des machines telles que les mécanismes entraînés par des câbles. L'une des principales exigences en raison de cette interaction que les robots doivent répondre aux actions humaines d'une manière sécuritaire et collaboratif. En conséquence, de nombreux problèmes ont été soulevés tels que la commande et la stabilité dues au contact physique entre l’humain et le robot. Aussi, l'un des enjeux les plus importants est de garantir un espace sans collision (pour éviter les collisions entre des câbles et un opérateur et éviter les collisions entre les câbles entre eux). Le but de ce projet de recherche est de modéliser, concevoir, analyser et mettre en œuvre un mécanisme parallèle reconfigurable à six degrés de liberté entraîné par huit câbles. La principale contribution de ces travaux de recherche est de développer un modèle non linéaire et résolvez le problème de cinématique direct et inverse d'un CDPM entièrement contraint étant donné que les points d'attache sur les rails se déplacent verticalement (les mécanismes entraînés par des câbles conventionnels ont des points d'attache fixes sur les rails) tout en contrôlant les longueurs des câbles. Dans une deuxième étape, l’idée de la reconfiguration est ensuite utilisée pour éviter les interférences entre les câbles et entre les câbles et les membres d’un opérateur en temps réel en déplaçant un point de fixation du câble sur le cadre pour augmenter la distance la plus courte entre eux tout en gardant la trajectoire de l'effecteur terminal inchangée. Troisièmement, la nouvelle approche proposée a été évaluée et testée en créant une trajectoire d'interférence câble-câble et câble-humain simulée, détectant et évitant ainsi les collisions câble-câble et câble-humain en utilisant la reconfiguration en temps réel proposée tout en conservant la trajectoire effectrice finale. Enfin la dernière étape des travaux de recherche consiste à étudiez l'effet du déplacement des points d'attache sur l'espace de travail réalisable du CDPM

Reconfigurable fully constrained cable-driven parallel mechanism for avoiding collision between cables with human

Productivity can be increased by manipulators tracking the desired trajectory with some constraints. Humans as moving obstacles in a shared workspace are one of the most challenging problems for cable-driven parallel mechanisms (CDPMs) that are considered in this research. One of the essential primary issues in CDPM is collision avoidance among cables and humans in the shared workspace. This paper presents a model and simulation of a reconfigurable, fully constrained CDPM enabling detection and avoidance of cable–human collision. In this method, unlike conventional CDPMs where the attachment points are fixed, the attachment points on the rails can be moved (up and down on their rails), and then the geometric configuration is adapted. Karush–Kuhn–Tucker method is proposed, which focuses on estimating the shortest distance among moving obstacles (human limbs) and all cables. When cable and limbs are close to colliding, the new idea of reconfiguration is presented by moving the cable’s attachment point on the rail to increase the distance between the cables and human limbs while they are both moving. Also, the trajectory of the end effector remains unchanged. Some simulation results of reconfiguration theory as a new approach are shown for the eight-cable-driven parallel manipulator, including the workspace boundary variation. The proposed method could find a collision-free predefined path, according to the simulation results

Biomechatronics: Harmonizing Mechatronic Systems with Human Beings

This eBook provides a comprehensive treatise on modern biomechatronic systems centred around human applications. A particular emphasis is given to exoskeleton designs for assistance and training with advanced interfaces in human-machine interaction. Some of these designs are validated with experimental results which the reader will find very informative as building-blocks for designing such systems. This eBook will be ideally suited to those researching in biomechatronic area with bio-feedback applications or those who are involved in high-end research on manmachine interfaces. This may also serve as a textbook for biomechatronic design at post-graduate level

Instrumentation and validation of a robotic cane for transportation and fall prevention in patients with affected mobility

Dissertação de mestrado integrado em Engenharia Física, (especialização em Dispositivos, Microssistemas e Nanotecnologias)O ato de andar é conhecido por ser a forma primitiva de locomoção do ser humano, sendo que este traz muitos benefícios que motivam um estilo de vida saudável e ativo. No entanto, há condições de saúde que dificultam a realização da marcha, o que por consequência pode resultar num agravamento da saúde, e adicionalmente, levar a um maior risco de quedas. Nesse sentido, o desenvolvimento de um sistema de deteção e prevenção de quedas, integrado num dispositivo auxiliar de marcha, seria essencial para reduzir estes eventos de quedas e melhorar a qualidade de vida das pessoas. Para ultrapassar estas necessidades e limitações, esta dissertação tem como objetivo validar e instrumentar uma bengala robótica, denominada Anti-fall Robotic Cane (ARCane), concebida para incorporar um sistema de deteção de quedas e um mecanismo de atuação que possibilite a prevenção de quedas, ao mesmo tempo que assiste a marcha. Para esse fim, foi realizada uma revisão do estado da arte em bengalas robóticas para adquirir um conhecimento amplo e aprofundado dos componentes, mecanismos e estratégias utilizadas, bem como os protocolos experimentais, principais resultados, limitações e desafios em dispositivos existentes. Numa primeira fase, foi estipulado o objetivo de: (i) adaptar a missão do produto; (ii) estudar as necessidades do consumidor; e (iii) atualizar as especificações alvo da ARCane, continuação do trabalho de equipa, para obter um produto com design e engenharia compatível com o mercado. Foi depois estabelecida a arquitetura de hardware e discutidos os componentes a ser instrumentados na ARCane. Em seguida foram realizados testes de interoperabilidade a fim de validar o funcionamento singular e coletivo dos componentes. Relativamente ao controlo de movimento, foi desenvolvido um sistema inovador, de baixo custo e intuitivo, capaz de detetar a intenção do movimento e de reconhecer as fases da marcha do utilizador. Esta implementação foi validada com seis voluntários saudáveis que realizaram testes de marcha com a ARCane para testar sua operabilidade num ambiente de contexto real. Obteve-se uma precisão de 97% e de 90% em relação à deteção da intenção de movimento e ao reconhecimento da fase da marcha do utilizador. Por fim, foi projetado um método de deteção de quedas e mecanismo de prevenção de quedas para futura implementação na ARCane. Foi ainda proposta uma melhoria do método de deteção de quedas, de modo a superar as limitações associadas, bem como a proposta de dispositivos de deteção a serem implementados na ARCane para obter um sistema completo de deteção de quedas.The act of walking is known to be the primitive form of the human being, and it brings many benefits that motivate a healthy and active lifestyle. However, there are health conditions that make walking difficult, which, consequently, can result in worse health and, in addition, lead to a greater risk of falls. Thus, the development of a fall detection and prevention system integrated with a walking aid would be essential to reduce these fall events and improve people quality of life. To overcome these needs and limitations, this dissertation aims to validate and instrument a cane-type robot, called Anti-fall Robotic Cane (ARCane), designed to incorporate a fall detection system and an actuation mechanism that allow the prevention of falls, while assisting the gait. Therefore, a State-of-the-Art review concerning robotic canes was carried out to acquire a broad and in-depth knowledge of the used components, mechanisms and strategies, as well as the experimental protocols, main results, limitations and challenges on existing devices. On a first stage, it was set an objective to (i) enhance the product's mission statement; (ii) study the consumer needs; and (iii) update the target specifications of the ARCane, extending teamwork, to obtain a product with a market-compatible design and engineering that meets the needs and desires of the ARCane users. It was then established the hardware architecture of the ARCane and discussed the electronic components that will instrument the control, sensory, actuator and power units, being afterwards subjected to interoperability tests to validate the singular and collective functioning of cane components altogether. Regarding the motion control of robotic canes, an innovative, cost-effective and intuitive motion control system was developed, providing user movement intention recognition, and identification of the user's gait phases. This implementation was validated with six healthy volunteers who carried out gait trials with the ARCane, in order to test its operability in a real context environment. An accuracy of 97% was achieved for user motion intention recognition and 90% for user gait phase recognition, using the proposed motion control system. Finally, it was idealized a fall detection method and fall prevention mechanism for a future implementation in the ARCane, based on methods applied to robotic canes in the literature. It was also proposed an improvement of the fall detection method in order to overcome its associated limitations, as well as detection devices to be implemented into the ARCane to achieve a complete fall detection system

Étude d’un système interactif sécuritaire dédié à l’interaction humain-robot appliqué à des mécanismes parallèles entraînés par des câbles

Depuis l'introduction des premiers robots interactifs en industrie, qui étaient à la base des systèmes collaboratifs supposés assister les humains dans les tâches pénibles et éprouvantes physiquement, le domaine de l’interaction humain-robot a fait des progrès considérables. Actuellement, les robots et les humains peuvent coexister conjointement dans un espace hybride afin de partager des tâches de production ou de partager le temps dans l’exécution d’une activité. Cependant, les nouveaux besoins industriels doivent conduire à des recherches pour adapter les chaînes de production et les rendre plus flexible et réactive à la modification des caractéristiques des produits. L’une des solutions consiste à adapter le manipulateur industriel présent dans les lignes de production à des fins d’interaction et de collaboration. Toutefois, la présence de l’humain dans l’espace de travail d’un manipulateur (cellule de travail hybride) représente un réel défi dans le domaine de l’interaction humain-robot puisque cela consiste à l’intégration d’une multitude de variétés de capteurs dits intelligents, surtout dans le cas de l’utilisation d’un mécanisme parallèle entraîné par des câbles. Pour cette raison, plusieurs problématiques ont été soulevées, pour lesquelles peu ou pas de recherches sont réalisées : cette nouvelle technologie est introduite sans entraînement de l’opérateur, l’évaluation de la sécurité a été très peu explorée lors de l’interaction et la performance de son utilisation demeure peu évaluée dans un contexte de réduction des troubles musculosquelettiques (TMS). Le projet de recherche vise l’étude et la conception d’un système interactif permettant d’améliorer la sécurité et l’intuitivité des personnes qui interagissent avec des mécanismes parallèles entraînés par des câbles. Deux modes d’interaction sont étudiés dans le système interactif, à savoir le partage des activités et l’interaction physique. En premier lieu, une méthode de génération de trajectoires avec évitement de collisions appliquée pour le mode de partage des activités est proposée. L’effecteur du manipulateur suit un chemin dans l’espace opérationnel à travers des points de passage. Ces derniers sont générés par un réseau de neurones rétropropagation (Back-propagation), et sont reliés par un polynôme quintique (de degré cinq). En outre, la géométrie déformable de l’obstacle et l’environnement dynamique sont pris en compte dans la méthode. En second lieu, une approche est abordée pour déterminer la distance minimale entre les câbles et identifier ceux qui sont en interférence. Le calcul de distance est exécuté en temps réel à travers un algorithme. En outre, les contraintes physiques des câbles ont été prises en compte dans la modélisation mathématique et formulées en un problème d’optimisation non linéaire. Ce dernier est résolu en utilisant l’approche de Karush-Kuhn-Tucker (KKT). Cette méthode de calcul de distance est intégrée à une loi de commande interactive permettant de gérer les câbles en interférence pendant l’interaction physique avec le mécanisme. Une force est calculée et introduite dans la boucle de la commande afin d’éviter le croisement et le relâchement des câbles en interférence. Par ce fait, la tâche est exécutée jusqu’aux limites des possibilités géométriques et cinématiques du mécanisme. Par ailleurs, cette stratégie est basée sur une commande en admittance pour permettre l’interaction physiquement avec un mécanisme parallèle entrainé par des câbles. Un algorithme permettant de sélectionner entre ces deux modes est proposé. Cette approche inclut un vêtement intelligent pour le changement de mode de manière intuitive simple et rapide. L’algorithme est exécuté en temps réel et basé sur une identification de gestes utilisant un polynôme d’interpolation trigonométrique. Les signaux analysés proviennent d’une semelle instrumentée qui est située au niveau du pied. Enfin, les différents algorithmes et stratégies sont validés en simulations et à travers des expérimentations sur un mécanisme parallèle entrainé par sept câbles. Ce projet de thèse apporte plusieurs contributions dans le domaine de l’interaction humain-robot notamment la capacité d’adaptation du système interactif pour des tâches industrielles. Since the introduction of the first interactive robots in industry, which was the collaborative robots (labelled as COBOT), the field of human robot interaction has made considerable progress. In its early version, those robots were used to increase muscle strength of the operator for moving heavy loads. Recently, robots and humans can share the same workspace, production activities or working time. However, new needs in industry require more flexibility and reactivity supporting fast changes in product characteristics. One solution consists in the adaptation of an industrial robot, that is already installed in the production line, for interaction and collaboration purposes such as kinetic learning assembly task, and adaptive third hand. However, the presence of the human in the manipulators’ workspace (hybrid work cell) represents a real challenge in the field of human-robot interaction. It consists in the integration of an intelligent sensor varieties, especially when the cables driven parallel mechanisms (CDPM) are used for an interaction task. For these reasons, several issues have been raised, for which few or no research has been done yet. This new technology is introduced without any operators training and the safety assessment has been very little explored during the interaction. Moreover, the performance of its use remains poorly evaluated in a context of reduction of musculoskeletal disorders (MSDs). The research project aims to study and design an interactive system in order to improve the safety and the intuitivity when the humans interact with cables driven parallel mechanisms. Two modes of cooperation are studied in the interactive system, namely the sharing of activities and the physical interaction. First, a trajectory generating method for an industrial manipulator in a shared workspace is proposed. A neural network using a supervised learning is applied to create the waypoints required for dynamic obstacles avoidance. These points are linked with a quintic polynomial function for smooth motion which is optimized using least-square to compute an optimal trajectory. Moreover, the evaluation of human motion forms has been taken into consideration in the proposed strategy. Second, a mathematical approach is presented to determine the minimum distance between cables and to identify which ones are interfering. To execute this approach in real time, an algorithm is also presented for calculating this distance. Furthermore, the physical constraints of the cables have been considered in mathematical modeling and formulated into a nonlinear optimization problem. The latter is solved using the Karush-Kuhn-Tucker (KKT) approach. This method of distance calculation is integrated with a new interactive control that eliminates the computation of the effect of a folding interfered cable. A control strategy is proposed, which allows to manage the cables in interference while the operator physically interacts with the mechanism. A repulsive force is generated and introduced to the controller to avoid the cables crossing and folding. Therefore, the task is executed within the limits of the kinematic possibilities. Moreover, this strategy is based on an admittance control for physically interacting with a CDPM. In order to allow a change of intuitive interaction mode, an algorithm for selecting between these two modes is proposed. This approach includes an instrumented insole placed into a shoe for intuitive mode change quick and easy. The algorithm is executed in real time and based on a gesture identification using a trigonometric interpolation polynomial. Finally, theses different strategies and algorithms are validated in simulations and through experiments on a parallel mechanism driven by seven cables. This thesis project brings several contributions in the field of human-robot interaction including the ability of the interactive system to adapt for industrial tasks

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications

Robotics 2010

Without a doubt, robotics has made an incredible progress over the last decades. The vision of developing, designing and creating technical systems that help humans to achieve hard and complex tasks, has intelligently led to an incredible variety of solutions. There are barely technical fields that could exhibit more interdisciplinary interconnections like robotics. This fact is generated by highly complex challenges imposed by robotic systems, especially the requirement on intelligent and autonomous operation. This book tries to give an insight into the evolutionary process that takes place in robotics. It provides articles covering a wide range of this exciting area. The progress of technical challenges and concepts may illuminate the relationship between developments that seem to be completely different at first sight. The robotics remains an exciting scientific and engineering field. The community looks optimistically ahead and also looks forward for the future challenges and new development