Planar robotic systems for upper-limb . . .

Rehabilitation is the only way to promote recovery of lost function in post

Dynamically Feasible Trajectories of Fully-Constrained Cable-Suspended Parallel Robots

Cable-Driven Parallel Robots employ multiple cables, whose lengths are controlled by winches, to move an end-effector (EE). In addition to the advantages of other parallel robots, such as low moving inertias and the potential for high dynamics, they also provide specific advantages, such as large workspaces and lower costs. Thus, over the last 30 years, they have been the object of academic research; also, they are being employed in industrial applications. The main issue with cable actuation is its unilaterality, as cables must remain in tension: if they become slack, there is a risk of losing control of the EE's pose. This complicates the control of cable-driven robots and is among the most studied topics in this field. Most previous works resort to extra cables or rigid elements pushing on the EE to guarantee that cables remain taut, but this complicates robot design. An alternative is to use the gravitational and inertial forces acting on the EE to keep cables in tension. This thesis shows that the robot's workspace can be greatly increased, by considering two model architectures. Moreover, practical limits to the feasibility of a motion, such as singularities of the kinematic chain and interference between cables, are considered. Even if a motion is feasible, there is no guarantee that it can be performed with an acceptable precision in the end-effector's pose, due to the inevitable errors in the positioning of the actuators and the elastic deflections of the structure. Therefore, a set of indexes are evaluated to measure the sensitivity of the end-effector's pose to actuation errors. Finally, the stiffness of one of the two architectures is modeled and indexes to measure the global compliance of the robot due to the elasticity of the cables are presented.I robot paralleli a cavi impiegano cavi, la cui lunghezza è controllata da argani, per muovere un elemento terminale o end-effector (EE). Oltre ai vantaggi degli altri robot paralleli, come basse inerzie in movimento e la possibilità di raggiungere velocità e accelerazioni elevate, possono anche fornire vantaggi specifici, come ampi spazi di lavoro e costi inferiori. Pertanto, negli ultimi 30 anni, questi robot sono stati oggetto di ricerche accademiche e stanno trovando applicazione anche in campo industriale. Il problema principale dell'azionamento mediante cavi è che è unilaterale, poiché i cavi possono essere tesi ma non compressi: quando diventano laschi, si rischia di perdere il controllo della posa dell'EE. Questo complica il controllo dei robot ed è uno dei temi più studiati nel settore. Gli studi compiuti sinora ricorrono prevalentemente a cavi addizionali o a elementi rigidi che spingono sull'EE per garantire che i cavi rimangano tesi, ma questo complica la progettazione dei robot. Un'alternativa è sfruttare le forze gravitazionali e inerziali che agiscono sull'EE per mantenere i cavi in tensione. Questa tesi dimostra che, in questo caso, lo spazio di lavoro del robot può essere notevolmente aumentato, applicando questo concetto a due architetture modello. Inoltre, vengono considerati i limiti imposti all'effettiva realizzabilità di un movimento, come le singolarità della catena cinematica e l'interferenza tra i cavi. Anche se un movimento è fattibile, non è garantito che si possa eseguire con precisione accettabile, a causa degli inevitabili errori di posizionamento degli attuatori e delle deformazioni elastiche della struttura. Si valutano quindi alcuni indici per misurare la sensibilità della posizione dell'elemento terminale agli errori di azionamento. Infine, è modellata la rigidezza di una delle due architetture proposte e sono presentati indici per misurare la cedevolezza globale del robot dovuta all'elasticità dei cavi

Parallel Manipulators

In recent years, parallel kinematics mechanisms have attracted a lot of attention from the academic and industrial communities due to potential applications not only as robot manipulators but also as machine tools. Generally, the criteria used to compare the performance of traditional serial robots and parallel robots are the workspace, the ratio between the payload and the robot mass, accuracy, and dynamic behaviour. In addition to the reduced coupling effect between joints, parallel robots bring the benefits of much higher payload-robot mass ratios, superior accuracy and greater stiffness; qualities which lead to better dynamic performance. The main drawback with parallel robots is the relatively small workspace. A great deal of research on parallel robots has been carried out worldwide, and a large number of parallel mechanism systems have been built for various applications, such as remote handling, machine tools, medical robots, simulators, micro-robots, and humanoid robots. This book opens a window to exceptional research and development work on parallel mechanisms contributed by authors from around the world. Through this window the reader can get a good view of current parallel robot research and applications

고층빌딩 곤돌라 탑재용 외부 유리창 청소로봇 유닛 개발

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 기계공학과, 2019. 2. 김종원.Walls of high-rise buildings are cleaned manually several times in a year by workers in a gondola. The cleaning work is difficult and extremely dangerous for human workers and there are several ongoing studies to automate this work by means of robotic solutions. To achieve a successful cleaning performance, a cleaning operation has to adapt to the environmental conditions. In this study, we design and assemble a manipulator to be used in wall-cleaning applications. From the design requirements identified by investigating a high-rise building in Korea, we determined the two important degrees-of-freedom (DOF), and a parallel mechanism is designed to achieve the motion. With the parallel configuration, the design parameters are optimized based on a dynamic index to achieve high cleaning performance in a gondola. A prototype is assembled, and the cleaning performance is verified on a test bench. A field test with the developed manipulator will be performed in the near future.빌딩의 빌딩의 벽은 청소 근로자가 근로자가 일 년에 수 차례 직접 곤돌라에 곤돌라에 탑승하여 청소합니다 청소합니다 . 청소 작업은 작업은 단순 노동이지만 노동이지만 고층에서의 고층에서의 고층에서의 작업이므로 작업이므로 매우 위험합니다 위험합니다 . 그리하여 그리하여 로봇을 로봇을 사용하여 사용하여 이 작업을 작업을 자동화하는 자동화하는 지속적인 지속적인 여러 가지 연구가 연구가 있었습니다 있었습니다 . 청소 작업에 가장 중요한 청소 성능을 성능을 높이기 높이기 위해서는 위해서는 청소 조건이 조건이 청소 환경에 환경에 적응해야 적응해야 적응해야 합니다 . 본 연구에서는 연구에서는 연구에서는 외벽 청소작업에 청소작업에 사용할 매니퓰레이터를 매니퓰레이터를 매니퓰레이터를 설계하고 제작 합니다 합니다 . 고층빌딩에 유지보수와 청소작업을 위해 의무 적으로 설치되어있는 곤돌라에 탑재하는 새로운 개념의 청소 로봇입니다 . 한국의 고층 건물을 건물을 조사해서 조사해서 나온 설계 요구 사항에서 사항에서 두 가지 중요한 중요한 매니퓰레이터의 자유도 (DOF)를 결정했습니다 결정했습니다 . 그 후, 모션을 구현하기 위한 병렬 매니퓰레이터 매니퓰레이터 매니퓰레이터 메커니즘을 메커니즘을 설계했습니다 설계했습니다 . 곤돌라에서 곤돌라에서 높은 청소 성능을 성능을 얻기 위해 병렬 매커니즘의 동적 인덱스를 기반으로 기반으로 설계 변수를 최적화 최적화 하였습니다. 그 후, 프로토 타입을 타입을 조립하고 조립하고 세척 성능을 성능을 테스트 벤치에서 벤치에서 확인합니다.1. Introduction . 1 2. Condition for wall-cleaning operation . 4 2.1 63-story building and gondola specification . 4 2.2 Cleaning operation and cleaning performace 4 2.3 Motion and constraints of the gondola motion . 5 3. 2-DOF manipulator for cleaning operation . 7 3.1 Kinematic configuration and modeling 7 3.2 Jacobian matrix . 10 3.3 Dynamic analysis 11 3.4 Mass matrix of the manipulator 12 4. Optimal design . 23 4.1 Dynamic manipulator isotropy index 23 4.2 Workspace constraints 25 4.3 Optimization problem definition . 25 4.4 Optimal design result 25 5. Prototype and experiment . 31 6. Conclusion 31 Reference 32 초록 . 34Maste

Mechatronic design solution for planar overconstrained cable-driven parallel robot

Cable-driven parallel robots (CDPRs) combine the successful features of parallel manipulators with the benefits of cable transmissions. The payload is divided among light extendable cables, resulting in an energy-efficient system that can achieve high end-effector acceleration over a huge workspace. A CDPR is formed by a set of actuation units, and a mobile platform, working as an end-effector (EE). The cables, driven by the actuation units, are guided inside the robot workspace using a guidance system and then connected to the mobile platform. The variation of cable lengths is responsible for the EE displacement throughout the robot workspace. These features result in easily reconfigurable systems where the workspace can be modified by relocating the actuation and guidance units. Nevertheless, the use of CDPRs in industrial environments is still limited, due to the drawbacks of employing flexible cables. Indeed, cables impose unilateral constraints that can only exert tensile forces and, consequently, the EE cannot withstand any arbitrary external action. To enhance the robot’s controllability, CDPRs can be overconstrained by employing a number of cables higher than the degrees of freedom of the EE. This allows cables to pull one against the other and to keep the overall system controllable over a wide range of externally applied loads. In this thesis, an eight-cable, planar, overconstrained CDPR is designed: the robot has the deployable and reconfigurable features required by the task. In particular, this CDPR has its actuation units installed into the EE mobile platform, and the frame anchor points can be rearranged to obtain a discrete reconfiguration. The cable arrangement, location of anchor points and mechanical design have been studied, by implementing a hybrid optimisation procedure. The genetic algorithm is combined with a local minimum optimiser, maximizing the CDPR volume index and deriving a mechanical design for the prototype

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

Appropriate Design of Parallel Manipulators

International audienceAlthough parallel structures have found a niche market in many applications such as machine tools, telescope positioning or food packaging, they are not as successful as expected. The main reason of this relative lack of success is that the study and hardware of parallel structures have clearly not reached the same level of completeness than the one of serial structures. Among the main issues that have to be addressed, the design problem is crucial. Indeed, the performances that can be expected from a parallel robot are heavily dependent upon the choice of the mechanical structure and even more from its dimensioning. In this chapter, we show that classical design methodologies are not appropriate for such closed-loop mechanism and examine what alternatives are possible

The 29th Aerospace Mechanisms Symposium

The proceedings of the 29th Aerospace Mechanisms Symposium, which was hosted by NASA Johnson Space Center and held at the South Shore Harbour Conference Facility on May 17-19, 1995, are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, pointing mechanisms joints, bearings, release devices, booms, robotic mechanisms, and other mechanisms for spacecraft

Advances in Robot Kinematics : Proceedings of the 15th international conference on Advances in Robot Kinematics

International audienceThe motion of mechanisms, kinematics, is one of the most fundamental aspect of robot design, analysis and control but is also relevant to other scientific domains such as biome- chanics, molecular biology, . . . . The series of books on Advances in Robot Kinematics (ARK) report the latest achievement in this field. ARK has a long history as the first book was published in 1991 and since then new issues have been published every 2 years. Each book is the follow-up of a single-track symposium in which the participants exchange their results and opinions in a meeting that bring together the best of world’s researchers and scientists together with young students. Since 1992 the ARK symposia have come under the patronage of the International Federation for the Promotion of Machine Science-IFToMM.This book is the 13th in the series and is the result of peer-review process intended to select the newest and most original achievements in this field. For the first time the articles of this symposium will be published in a green open-access archive to favor free dissemination of the results. However the book will also be o↵ered as a on-demand printed book.The papers proposed in this book show that robot kinematics is an exciting domain with an immense number of research challenges that go well beyond the field of robotics.The last symposium related with this book was organized by the French National Re- search Institute in Computer Science and Control Theory (INRIA) in Grasse, France