Design of a partially-coupled self-adaptive robotic finger optimized for collaborative robots

This paper presents the design and optimization of a self-adaptive, a.k.a. underactuated, finger targeted to be used with collaborative robots. Typical robots, whether collaborative or not, mostly rely on standard translational grippers for pick-and-place operations. These grippers are constituted from an actuated motion platform on which a set of jaws is rigidly attached. These jaws are often designed to secure a precise and limited range of objects through the application of pinching forces. In this paper, the design of a self-adaptive robotic finger is presented which can be attached to these typical translational gripper to replace the common monolithic jaws and provide the gripper with shape-adaptation capabilities without any control or sensors. A new design is introduced here and specially optimized for collaborative robots. The kinetostatic analysis of this new design is first discussed and then followed by the optimization of relevant geometric parameters taking into account the specificities of collaborative robots. Finally, a practical prototype attached to a very common collaborative robot is demonstrated. While the resulting finger design could be attached to any translational gripper, specifically targeting collaborative robots as an application allows for more liberty in the choice of certain design parameters and more constraints for others

Design and Analysis of Underactuated compliant mechanisms

Precession and accuracy are important in several mechanisms in practical use. Compliant mechanism provides a solution for such mechanical design problems. It has several other advantages over rigid body mechanism. That is why nowadays a lot of research work is going on in this field. But the main disadvantage of this kind of mechanism is its complexity to analyse and design. So, in order to make the analysis simpler pseudo rigid body model (PRBM) technique is often adopted. A mechanism is called underactuated when it has more degrees of freedom than number of inputs or actuations. For such mechanisms we have to perform the kinematic analysis along with force analysis to obtain the solutions. In this work, two underactuated partially compliant mechanisms have been discussed. In the first case, a partially compliant slider-crank mechanism without any input actuation is taken into account. The kinematic and static force equations are solved numerically to find out equilibrium position of the mechanism. Here, the input is provided by two torsional springs. The second case considered is a two-degree of freedom five bar slider mechanism with one input actuator only. Kinematic analysis along with force analysis using principle of virtual work is illustrated to find the solution. The nonlinear algebraic equations obtained are solved simultaneously based on Newton-Raphson method using a computer program in C and the graphs are plotted between input data and other parameters. In both the cases, input data is taken from references for comparison point-of-view

Mesure tactile proprioceptive pour des doigts sous-actionnés

RÉSUMÉ La préhension et la manipulation d’objets par des robots deviennent de plus en plus répandues dans divers domaines, et ce, pour de multiples applications. L’utilisation de robots permet d’améliorer la répétabilité, la rapidité et la précision lors de certaines tâches, et ce, comparativement aux performances d’un opérateur humain. De plus, un robot peut également être conçu pour accomplir certaines tâches qu’une personne ne pourrait effectuer, que ce soit au niveau de la force nécessaire ou du manque d’espace pour manoeuvrer. Des robots peuvent également plus aisément fonctionner dans des environnements hostiles. Tout comme pour l’être humain, la rétroaction tactile est particulièrement utile et même inévitable pour effectuer certaines tâches. Il faut toutefois souligner qu’il s’agit d’un thème de recherche où l’on est encore bien loin d’avoir atteint les performances humaines. Pour s’en approcher, de nombreuses et diverses technologies de capteurs tactiles existent, mais chacune comporte ses défauts. Ainsi, bien qu’il existe actuellement des solutions technologiques pour donner une rétroaction sensorielle à un robot ou à son opérateur, ces dernières s’avèrent généralement coûteuses, présentent différents défauts au niveau de la sensibilité et ne sont pas toujours adaptées à certaines utilisations. Dans l’optique de trouver une alternative efficace aux technologies conventionnelles de détection et de mesure tactiles, la présente thèse se concentre sur la possibilité d’utiliser la raideur inhérente du mécanisme de transmission d’un doigt sous-actionné. En effet, les doigts et les mains sous-actionnés sont de plus en plus communément utilisés pour leur simplicité propre et leur capacité à saisir et à s’adapter à la forme d’objet de manière purement mécanique sans schéma de commande complexe ou de nombreux actionneurs. Contrairement aux mécanismes pleinement actionnés, les doigts sous-actionnés, communément appelés adaptatifs, comportent des éléments passifs pour contraindre leur mouvement avant le contact, tout en permettant d’obtenir une prise stable sans développer des forces de contact trop élevées initialement. Les doigts sous-actionnés étant généralement dépourvus d’actionneurs à l’intérieur du doigt lui-même, les seuls capteurs déjà présents sont typiquement situés à l’unique actionneur. Toutefois, en analysant et traitant en temps réel les données de ces capteurs internes, également appelés proprioceptifs, il est possible d’extraire une panoplie d’informations sur ce qui se passe au niveau des phalanges. Ce principe est donc utilisé pour obtenir des algorithmes de détection tactile pouvant être utilisés sur différents systèmes, tels qu’une pince compliante et un préhenseurs à membrures.----------ABSTRACT Robotic hands have become more and more prevalent in many fields. They have replaced human operators in many repetitive applications where robots become more precise and efficient. Moreover, robotic graspers can lift heavier loads and accomplish maneuvers a human could not. They can also manipulate objects in hostile environments where it would be dangerous for humans. Therefore, a lot of work has been done in recent years to improve their capabilities such as their speed, dexterity, strength, and versatility. However, current robotic manipulators lack the sensory feedback of their human counterparts. Indeed, haptic and tactile feedbacks are still very limited in current devices, which may be a problem, because tactile sensing is deemed nearly mandatory for a large number of applications. Conventional tactile sensors, which are usually applied on the external surface of a robot, are generally used, but they can also be costly, insensitive to some dynamic phenomena, and not adequate to some applications. To solve these issues, many authors have worked on finding alternatives to standard tactile sensors. This thesis fits in this current trend by focusing on the possibility of using the internal stiffness of underactuated fingers to design a virtual tactile sensor. This technique is referred to as proprioceptive tactile sensing. It is applied here to underactuated robotics fingers, which are becoming prevalent in many fields. Underactuated mechanisms, sometimes referred to as self-adaptive, are particularly interesting because of their intrinsic ability to mechanically adapt themselves to the shape of an object without complex control laws and as low as only one actuator. As they have by definition less actuators, they generally have no sensor in the finger’s mechanism itself. Instead of adding new sensors, it is possible to take advantage of the sensors already present, such as the ones at the actuator. Therefore, in this thesis, only data provided by sensors at the actuator is used. Since a oneto-one relationship exists between the contact location and the instantaneous stiffness of the mechanism, it is possible to compute one from the other. Therefore, with the measurements from sensors at the actuator, it is possible to estimate the point of contact. To this aim, a complete model is proposed and experimental data is provided. Different algorithms were tested successfully on a compliant biocompatible gripper and a 2-DOF linkage-driven finger. Finally, an optimization procedure is presented with the aim of finding the optimal parameters of the transmission mechanism to improve the sensitivity of the virtual tactile sensor. The data presented in this thesis demonstrate the robustness of the proposed proprioceptive tactile sensing (PTS) technique

Adaptive and reconfigurable robotic gripper hands with a meso-scale gripping range

Grippers and robotic hands are essential and important end-effectors of robotic manipulators. Developing a gripper hand that can grasp a large variety of objects precisely and stably is still an aspiration even though research in this area has been carried out for several decades. This thesis provides a development approach and a series of gripper hands which can bridge the gap between micro-gripper and macro-gripper by extending the gripping range to the mesoscopic scale (meso-scale). Reconfigurable topology and variable mobility of the design offer versatility and adaptability for the changing environment and demands. By investigating human grasping behaviours and the unique structures of human hand, a CFB-based finger joint for anthropomorphic finger is developed to mimic a human finger with a large grasping range. The centrodes of CFB mechanism are explored and a contact-aided CFB mechanism is developed to increase stiffness of finger joints. An integrated gripper structure comprising cross four-bar (CFB) and remote-centre-of-motion (RCM) mechanisms is developed to mimic key functionalities of human hand. Kinematics and kinetostatic analyses of the CFB mechanism for multimode gripping are conducted to achieve passive-adjusting motion. A novel RCM-based finger with angular, parallel and underactuated motion is invented. Kinematics and stable gripping analyses of the RCM-based multi-motion finger are also investigated. The integrated design with CFB and RCM mechanisms provides a novel concept of a multi-mode gripper that aims to tackle the challenge of changing over for various sizes of objects gripping in mesoscopic scale range. Based on the novel designed mechanisms and design philosophy, a class of gripper hands in terms of adaptive meso-grippers, power-precision grippers and reconfigurable hands are developed. The novel features of the gripper hands are one degree of freedom (DoF), self-adaptive, reconfigurable and multi-mode. Prototypes are manufactured by 3D printing and the grasping abilities are tested to verify the design approach.EPSR

Dynamic grasping of objects with a high-speed parallel robot

Underactuated grippers aim to simplify the control strategies for performing stable grasps due to their inherent shape adaptability. While at the beginning, the main research area was focused on developing human-like robotic hands for disabled people, in the last years, a new eld of application appeared with the constant evolution of the industry: the implementation of a single underactuated gripper as a replacement of diverse dedicated fully-actuated grippers. However, two main issues are restraining its use: the stability of the grasp and the speed of performance. The rst is an active topic as all underactuated grippers need to ensure the stability of the grasped object through an adequate kinematic design, while, the latter is not widely treated as there weren't many application elds where high-speed was required and, at the end, the quasi-static analysis must be also ensured. For this reason, the present research work has been focused on the speed of the grasping. In the rst place, an introduction to underactuated hands is made, and is followed by two main stability criteria. Then, the development of a model for an underactuated nger that allows analyzing the complete grasping sequence at high-speed along with a collision model are presented. Following, a design-based analysis to simplify the model is performed, and the graspstate volume tool is introduced in order to inspect the impact of the design variables on the proposed criteria. In the last chapter, an optimization over the design space is performed and a design is chosen, crosschecked with ADAMS software and prototyped. Finally, an overview remarking the strengths and gaps in the research is presented in the form of conclusions, and closing them, future works that could be interesting to develop

Master of Science

thesisAutonomous and teleoperated flying robots capable of perch-and-stare are desirable for reconnaissance missions. Current solutions for perch-and-stare applications utilize various methods to enable aircraft to land on a limited set of surfaces that are typically horizontal or vertical planes. Motivated by the fact that songbirds are able to sleep in trees, without requiring active muscle control to stay perched, the research presented here details a concept that allows for passive perching of rotorcraft on a variety of surfaces. This thesis presents two prototype iterations, where perching is accomplished through the integration of two components: a compliant, underactuated gripping foot and a collapsing leg mechanism that converts aircraft weight into tendon tension in order to passively actuate the foot. This thesis presents the design process and analysis of the mechanisms. Additionally, stability tests were performed on the second prototype, attached to a quadrotor, that detail the versatility of the system and ability of the system to support external moments. The results show promise that it is possible to passively perch a rotorcraft on multiple surfaces and support reasonable environmental disturbances

Medical robots with potential applications in participatory and opportunistic remote sensing: A review

Among numerous applications of medical robotics, this paper concentrates on the design, optimal use and maintenance of the related technologies in the context of healthcare, rehabilitation and assistive robotics, and provides a comprehensive review of the latest advancements in the foregoing field of science and technology, while extensively dealing with the possible applications of participatory and opportunistic mobile sensing in the aforementioned domains. The main motivation for the latter choice is the variety of such applications in the settings having partial contributions to functionalities such as artery, radiosurgery, neurosurgery and vascular intervention. From a broad perspective, the aforementioned applications can be realized via various strategies and devices benefiting from detachable drives, intelligent robots, human-centric sensing and computing, miniature and micro-robots. Throughout the paper tens of subjects, including sensor-fusion, kinematic, dynamic and 3D tissue models are discussed based on the existing literature on the state-of-the-art technologies. In addition, from a managerial perspective, topics such as safety monitoring, security, privacy and evolutionary optimization of the operational efficiency are reviewed

Progettazione e Controllo di Mani Robotiche

The application of dexterous robotic hands out of research laboratories has been limited by the intrinsic complexity that these devices present. This is directly reflected as an economically unreasonable cost and a low overall reliability. Within the research reported in this thesis it is shown how the problem of complexity in the design of robotic hands can be tackled, taking advantage of modern technologies (i.e. rapid prototyping), leading to innovative concepts for the design of the mechanical structure, the actuation and sensory systems. The solutions adopted drastically reduce the prototyping and production costs and increase the reliability, reducing the number of parts required and averaging their single reliability factors. In order to get guidelines for the design process, the problem of robotic grasp and manipulation by a dual arm/hand system has been reviewed. In this way, the requirements that should be fulfilled at hardware level to guarantee successful execution of the task has been highlighted. The contribution of this research from the manipulation planning side focuses on the redundancy resolution that arise in the execution of the task in a dexterous arm/hand system. In literature the problem of coordination of arm and hand during manipulation of an object has been widely analyzed in theory but often experimentally demonstrated in simplified robotic setup. Our aim is to cover the lack in the study of this topic and experimentally evaluate it in a complex system as a anthropomorphic arm hand system

Design and Development of Sensor Integrated Robotic Hand

Most of the automated systems using robots as agents do use few sensors according to the need. However, there are situations where the tasks carried out by the end-effector, or for that matter by the robot hand needs multiple sensors. The hand, to make the best use of these sensors, and behave autonomously, requires a set of appropriate types of sensors which could be integrated in proper manners. The present research work aims at developing a sensor integrated robot hand that can collect information related to the assigned tasks, assimilate there correctly and then do task action as appropriate. The process of development involves selection of sensors of right types and of right specification, locating then at proper places in the hand, checking their functionality individually and calibrating them for the envisaged process. Since the sensors need to be integrated so that they perform in the desired manner collectively, an integration platform is created using NI PXIe-1082. A set of algorithm is developed for achieving the integrated model. The entire process is first modelled and simulated off line for possible modification in order to ensure that all the sensors do contribute towards the autonomy of the hand for desired activity. This work also involves design of a two-fingered gripper. The design is made in such a way that it is capable of carrying out the desired tasks and can accommodate all the sensors within its fold. The developed sensor integrated hand has been put to work and its performance test has been carried out. This hand can be very useful for part assembly work in industries for any shape of part with a limit on the size of the part in mind. The broad aim is to design, model simulate and develop an advanced robotic hand. Sensors for pick up contacts pressure, force, torque, position, surface profile shape using suitable sensing elements in a robot hand are to be introduced. The hand is a complex structure with large number of degrees of freedom and has multiple sensing capabilities apart from the associated sensing assistance from other organs. The present work is envisaged to add multiple sensors to a two-fingered robotic hand having motion capabilities and constraints similar to the human hand. There has been a good amount of research and development in this field during the last two decades a lot remains to be explored and achieved. The objective of the proposed work is to design, simulate and develop a sensor integrated robotic hand. Its potential applications can be proposed for industrial environments and in healthcare field. The industrial applications include electronic assembly tasks, lighter inspection tasks, etc. Application in healthcare could be in the areas of rehabilitation and assistive techniques. The work also aims to establish the requirement of the robotic hand for the target application areas, to identify the suitable kinds and model of sensors that can be integrated on hand control system. Functioning of motors in the robotic hand and integration of appropriate sensors for the desired motion is explained for the control of the various elements of the hand. Additional sensors, capable of collecting external information and information about the object for manipulation is explored. Processes are designed using various software and hardware tools such as mathematical computation MATLAB, OpenCV library and LabVIEW 2013 DAQ system as applicable, validated theoretically and finally implemented to develop an intelligent robotic hand. The multiple smart sensors are installed on a standard six degree-of-freedom industrial robot KAWASAKI RS06L articulated manipulator, with the two-finger pneumatic SHUNK robotic hand or designed prototype and robot control programs are integrated in such a manner that allows easy application of grasping in an industrial pick-and-place operation where the characteristics of the object can vary or are unknown. The effectiveness of the actual recommended structure is usually proven simply by experiments using calibration involving sensors and manipulator. The dissertation concludes with a summary of the contribution and the scope of further work

Kinematics and Robot Design II (KaRD2019) and III (KaRD2020)

This volume collects papers published in two Special Issues “Kinematics and Robot Design II, KaRD2019” (https://www.mdpi.com/journal/robotics/special_issues/KRD2019) and “Kinematics and Robot Design III, KaRD2020” (https://www.mdpi.com/journal/robotics/special_issues/KaRD2020), which are the second and third issues of the KaRD Special Issue series hosted by the open access journal robotics.The KaRD series is an open environment where researchers present their works and discuss all topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. It aims at being an established reference for researchers in the field as other serial international conferences/publications are. Even though the KaRD series publishes one Special Issue per year, all the received papers are peer-reviewed as soon as they are submitted and, if accepted, they are immediately published in MDPI Robotics. Kinematics is so intimately related to the design of robotic/automatic systems that the admitted topics of the KaRD series practically cover all the subjects normally present in well-established international conferences on “mechanisms and robotics”.KaRD2019 together with KaRD2020 received 22 papers and, after the peer-review process, accepted only 17 papers. The accepted papers cover problems related to theoretical/computational kinematics, to biomedical engineering and to other design/applicative aspects