Design and Implement Towards Enhanced Physical Interactive Performance Robot Bodies

In this thesis, it will introduce the design principle and implement details towards enhanced physical interactive performance robot bodies, which are more specically focused on under actuated principle robotic hands and articulated leg robots. Since they both signicantly function as the physical interactive robot bodies against external environment, while their current performance can hardly satisfy the requirement of undertaking missions in real application. Regarding to the enhanced physical interactive performances, my work will emphasis on the three following specific functionalities, high energy efficiency, high strength and physical sturdiness in both robotics actuation and mechanism. For achieving the aforementioned targets, multiple design methods have been applied, rstly the elastic energy storage elements and compliant actuation have been adopted in legged robots as Asymmetrical Compliant Actuation (ACA), implemented for not only single joint but also multiple joints as mono and biarticulation congurations in order to achieve higher energy effciency motion. Secondly the under actuated principle and modular nger design concept have been utilized on the development of robotic hands for enhancing the grasping strength and physical sturdiness meanwhile maintaining the manipulation dexterity. Lastly, a novel high payload active tuning Parallel Elastic Actuation (PEA) and Series Elastic Actuation (SEA) have been adopted on legged robots for augmenting energy eciency and physical sturdiness. My thesis contribution relies on the novel design and implement of robotics bodies for enhancing physical interactive performance and we experimentally veried the design effectiveness in specic designed scenario and practical applications

Design and Control of Compliant Actuation Topologies for Energy-Efficient Articulated Robots

Considerable advances have been made in the field of robotic actuation in recent years. At the heart of this has been increased use of compliance. Arguably the most common approach is that of Series-Elastic Actuation (SEA), and SEAs have evolved to become the core component of many articulated robots. Another approach is integration of compliance in parallel to the main actuation, referred to as Parallel- Elastic Actuation (PEA). A wide variety of such systems has been proposed. While both approaches have demonstrated significant potential benefits, a number of key challenges remain with regards to the design and control of such actuators. This thesis addresses some of the challenges that exist in design and control of compliant actuation systems. First, it investigates the design, dynamics, and control of SEAs as the core components of next-generation robots. We consider the influence of selected physical stiffness on torque controllability and backdrivability, and propose an optimality criterion for impedance rendering. Furthermore, we consider disturbance observers for robust torque control. Simulation studies and experimental data validate the analyses. Secondly, this work investigates augmentation of articulated robots with adjustable parallel compliance and multi-articulated actuation for increased energy efficiency. Particularly, design optimisation of parallel compliance topologies with adjustable pretension is proposed, including multi-articulated arrangements. Novel control strategies are developed for such systems. To validate the proposed concepts, novel hardware is designed, simulation studies are performed, and experimental data of two platforms are provided, that show the benefits over state-of-the-art SEA-only based actuatio

Compliant actuators that mimic biological muscle performance with applications in a highly biomimetic robotic arm

This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots, thereby fostering the evolution of these robotic systems. We introduce two novel compliant actuators, namely the Internal Torsion Spring Compliant Actuator (ICA) and the External Spring Compliant Actuator (ECA), and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator (MISA) through computational and experimental results. These actuators, employing a motor-tendon system, emulate biological muscle-like forms, enhancing artificial muscle technology. A robotic arm application inspired by the skeletal ligament system is presented. Experiments demonstrate satisfactory power in tasks like lifting dumbbells (peak power: 36W), playing table tennis (end-effector speed: 3.2 m/s), and door opening, without compromising biomimetic aesthetics. Compared to other linear stiffness serial elastic actuators (SEAs), ECA and ICA exhibit high power-to-volume (361 x 10^3 W/m) and power-to-mass (111.6 W/kg) ratios respectively, endorsing the biomimetic design's promise in robotic development

An Overview on Principles for Energy Efficient Robot Locomotion

Despite enhancements in the development of robotic systems, the energy economy of today's robots lags far behind that of biological systems. This is in particular critical for untethered legged robot locomotion. To elucidate the current stage of energy efficiency in legged robotic systems, this paper provides an overview on recent advancements in development of such platforms. The covered different perspectives include actuation, leg structure, control and locomotion principles. We review various robotic actuators exploiting compliance in series and in parallel with the drive-train to permit energy recycling during locomotion. We discuss the importance of limb segmentation under efficiency aspects and with respect to design, dynamics analysis and control of legged robots. This paper also reviews a number of control approaches allowing for energy efficient locomotion of robots by exploiting the natural dynamics of the system, and by utilizing optimal control approaches targeting locomotion expenditure. To this end, a set of locomotion principles elaborating on models for energetics, dynamics, and of the systems is studied

Robotic design and modelling of medical lower extremity exoskeletons

This study aims to explain the development of the robotic Lower Extremity Exoskeleton (LEE) systems between 1960 and 2019 in chronological order. The scans performed in the exoskeleton system’s design have shown that a modeling program, such as AnyBody, and OpenSim, should be used first to observe the design and software animation, followed by the mechanical development of the system using sensors and motors. Also, the use of OpenSim and AnyBody musculoskeletal system software has been proven to play an essential role in designing the human-exoskeleton by eliminating the high costs and risks of the mechanical designs. Furthermore, these modeling systems can enable rapid optimization of the LEE design by detecting the forces and torques falling on the human muscles

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

Learning Motion Skills for a Humanoid Robot

This thesis investigates the learning of motion skills for humanoid robots. As groundwork, a humanoid robot with integrated fall management was developed as an experimental platform. Then, two different approaches for creating motion skills were investigated. First, one that is based on Cartesian quintic splines with optimized parameters. Second, a reinforcement learning-based approach that utilizes the first approach as a reference motion to guide the learning. Both approaches were tested on the developed robot and on further simulated robots to show their generalization. A special focus was set on the locomotion skill, but a standing-up and kick skill are also discussed. Diese Dissertation beschäftigt sich mit dem Lernen von Bewegungsfähigkeiten für humanoide Roboter. Als Grundlage wurde zunächst ein humanoider Roboter mit integriertem Fall Management entwickelt, welcher als Experimentalplatform dient. Dann wurden zwei verschiedene Ansätze für die Erstellung von Bewegungsfähigkeiten untersucht. Zu erst einer der kartesische quintische Splines mit optimierten Parametern nutzt. Danach wurde ein Ansatz basierend auf bestärkendem Lernen untersucht, welcher den ersten Ansatz als Referenzbewegung benutzt. Beide Ansätze wurden sowohl auf der entwickelten Roboterplatform, als auch auf weiteren simulierten Robotern getestet um die Generalisierbarkeit zu zeigen. Ein besonderer Fokus wurde auf die Fähigkeit des Gehens gelegt, aber auch Aufsteh- und Schussfähigkeiten werden diskutiert

Design and evaluation of a powered prosthetic foot with monoarticular and biarticular actuation

To overcome the limitations of passive prosthetic feet, powered prostheses have been developed, that can provide the range of motion and power of their human counterparts. These devices can equalize spatio-temporal gait parameters and improve the metabolic effort compared to passive prostheses, but asymmetries and compensatory motions between the healthy and impaired leg remain. Unlike their human counter part, existing powered prosthetic feet are fully monoarticular actuating only the prosthetic ankle joint, whereas in the biological counter part, ankle and knee joint are additionally coupled by the biarticular gastrocnemius muscle. The goal of this work is to investigate the benefits of a powered biarticular transtibial prosthesis comprising mono- and biarticular actuators similar to the human example. The contributions of the present work are as follows: A biarticular prosthesis prototype is methodically designed to match the capabilities of the monoarticular muscles at the human ankle joint as well as the biarticular gastrocnemius muscle during level walking. The prototype consists of an existing powered monoarticular prosthetic foot, which is extended with a knee orthoses and a stationary biarticular Bowden cable actuator. Both actuators are modeled as serial elastic actuators (SEA) and the identification of the model parameters is conducted. A model based torque control utilizing the measurements commonly available in SEAs, an impedance control law based on human ankle reference trajectories, and a high level control to enable steady walking in the lab are introduced. The proposed hardware setup and control structure can provide sagittal plane angles and torques similar to the mono- and biarticular muscles at the human ankle, with proper torque tracking performance and a freely adjustable allocation of torque between the monoarticular and biarticular actuator. The biarticular prosthesis is evaluated in the gait lab with three subjects with unilateral transtibial amputation utilizing a continuous sweep experimental protocol to investigate the metabolic effort and spatio-temporal gait parameters. All subjects show a tendency to reduced metabolic effort for medium activity of the artificial gastrocnemius, although noise level and time variation are large. In addition to the reduction in metabolic effort, the artificial gastrocnemius is able to influence spatio temporal gait parameters between the impaired and the intact side, but partially opposing effects are observed among the individual subjects. In conclusion, this thesis describes the implementation of an artificial gastrocnemius following the human example and the systematic investigation of metabolic effort and spatio-temporal gait parameters. It is shown that the addition of the artificial gastrocnemius to a monoarticular prosthesis can positively affect the investigated parameters. The meaningfulness of the results should be improved by increased clinical effort in future work

Avances en la interacción física segura humano-robot y el desarrollo de sistemas elásticos articulares

Los brazos robóticos asistenciales forman parte importante de un grupo de aplicaciones robóticas que requieren una continua interacción física con el usuario. En la actualidad este tipo de robot suele garantizar la seguridad de las personas que comparten espacio con ellos, gracias a la imposición de un conjunto de restricciones mecánicas y de control, que habitualmente entran en conflicto con el rendimiento dinámico de los mismos, al menos en términos de velocidad y carga útil. Esta tesis aborda los problemas implícitos en el diseño de brazos robóticos asistenciales, a fin de garantizar un correcto equilibrio entre seguridad y desempeño. Presenta un conjunto de directrices de diseño y propone métodos adecuados para el modelado dinámico, control y evaluación de la seguridad durante la interacción con los seres humanos. Comienza planteando un nuevo modelo de colisión humano-robot, que toma en cuenta la velocidad relativa, las propiedades elásticas de los materiales y la geometría superficial, tanto del ser humano como del robot. Este modelo ofrece una medida de la seguridad más acorde con el tipo de lesiones que pueden ocurrir en la robótica asistencial. Además, facilita una mejor comprensión de la influencia, que tienen los diferentes parámetros de diseño, en las lesiones producto de colisiones. Posteriormente, se realiza un análisis exhaustivo de la influencia que tiene la elasticidad mecánica articular sobre la seguridad y desempeño de robots asistenciales. Como aporte a los sistemas mecánicos seguros, se controla y ensaya con un novedoso actuador de rigidez variable. Además, se diseña y desarrolla un innovador sistema elástico pasivo, que permite la conveniente programación de los perfiles de rigidez, para maximizar el desempeño y garantizar la seguridad. Estos mecanismos son validados a través de simulaciones y ensayos reales sobre un banco de pruebas. Por último, y con el fin de que los resultados de este trabajo puedan ser utilizados para una futura estandarización de los parámetros de diseño y evaluación de robots asistenciales seguros, se resumen una serie de recomendaciones para el análisis de riesgo, el diseño mecánico y las estrategias de control.Robotic assistance arms are an important part of a group of robotic applications that require continuous physical interaction with the user. At present, this type of robot usually guarantees the safety of people who share space with them, thanks to the imposition of a set of mechanical and control constraints, which usually conflict with their dynamic performance, at least in terms of speed and payload. This thesis addresses the problems implicit in the design of robotic assistance arms, in order to ensure a correct balance between safety and performance. It presents a set of design guidelines and proposes suitable methods for its dynamic modeling, control and evaluation of safety during interaction with humans. It begins by proposing a new model of human-robot collision, which takes into account the relative speed, elastic properties of materials and surface geometry, both human and robot. This model offers a measure of security more in line with the type of injuries that can occur in robotics assistance. In addition, it facilitates a better understanding of the influence of different design parameters have on the lesions produced from collisions. Next, a comprehensive analysis of the influence of mechanical elasticity on the safety and performance of assistance robots is performed. As a contribution to safe mechanical systems, it is controlled and tested with a new variable stiffness actuator. In addition, it designs and develops an innovative passive elastic system, which allows convenient programming of stiffness profiles, to maximize performance and ensure safety. These mechanisms are validated through simulations and actual tests on a test bench. Finally, and in order that the results of this work can be used for a future standardization of the parameters of design and evaluation of safe assistance robots, a series of recommendations for the risk analysis, the mechanical design and the strategies are summarized of control.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Pedro José Sanz Valero.- Secretario: Luis Santiago Garrido Bullón.- Vocal: Francisco de Asís Rodríguez Día