Modeling and Control of Flexible Link Manipulators

Autonomous maritime navigation and offshore operations have gained wide attention with the aim of reducing operational costs and increasing reliability and safety. Offshore operations, such as wind farm inspection, sea farm cleaning, and ship mooring, could be carried out autonomously or semi-autonomously by mounting one or more long-reach robots on the ship/vessel. In addition to offshore applications, long-reach manipulators can be used in many other engineering applications such as construction automation, aerospace industry, and space research. Some applications require the design of long and slender mechanical structures, which possess some degrees of flexibility and deflections because of the material used and the length of the links. The link elasticity causes deflection leading to problems in precise position control of the end-effector. So, it is necessary to compensate for the deflection of the long-reach arm to fully utilize the long-reach lightweight flexible manipulators. This thesis aims at presenting a unified understanding of modeling, control, and application of long-reach flexible manipulators. State-of-the-art dynamic modeling techniques and control schemes of the flexible link manipulators (FLMs) are discussed along with their merits, limitations, and challenges. The kinematics and dynamics of a planar multi-link flexible manipulator are presented. The effects of robot configuration and payload on the mode shapes and eigenfrequencies of the flexible links are discussed. A method to estimate and compensate for the static deflection of the multi-link flexible manipulators under gravity is proposed and experimentally validated. The redundant degree of freedom of the planar multi-link flexible manipulator is exploited to minimize vibrations. The application of a long-reach arm in autonomous mooring operation based on sensor fusion using camera and light detection and ranging (LiDAR) data is proposed.publishedVersio

Model-Based Robot Control and Multiprocessor Implementation

Model-based control of robot manipulators has been gaining momentum in recent years. Unfortunately there are very few experimental validations to accompany simulation results and as such majority of conclusions drawn lack the credibility associated with the real control implementation

Projektiranje i implementacija sustava upravljanja robotskim manipulatorom za udaljeno ispitivanje zavara na reaktorskim posudama

In this paper a design and implementation of a remote control system of a manipulator for weld inspection of nuclear reactor vessels are described. Based on the client-server TCP/IP software architecture, the presented control system enables an operator to perform the entire inspection procedure remotely over a network, avoiding exposure to dangerous radiation normally present in nuclear reactor environments. The developed graphical user interface provides tools for planning weld scan trajectories, their verification on a robot and reactor vessel 3D model, and finally, execution of planned trajectories on a remote robot. In addition, the weld inspection process can be monitored in parallel on a virtual robot and reactor vessel model and by watching live video streams captured by two cameras mounted on the robot.U ovom radu opisan je postupak projektiranja i implementacije sustava za udaljeno upravljanje robotskim manipulatorom koji služi za ispitivanje zavara na posudama nuklearnih reaktora. Opisani sustav temelji se na komunikacijskoj arhitekturi tipa TCP/IP klijent-poslužitelj, te omogućuje provedbu cjelokupnog postupka ispitivanja na daljinu, bez potrebe izlaganja opasnoj radijaciji koja je uobičajeno prisutna u okruženju nuklearnog reaktora. Postupak ispitivanja provodi se korištenjem razvijene programske aplikacije, koja putem grafičkog korisničkog sučelja operateru nudi alate za planiranje potrebnih trajektorija, njihovu provjeru na virtualnom 3D modelu posude i manipulatora, te izvršavanje na udaljenom manipulatoru. Operateru je također omogućen uvid u trenutno zbivanje u posudi tijekom cijelog postupka ispitivanja, paralelnim praćenjem virtualne 3D scene, te video slika s dvije specijalne kamere ugrađene na manipulatoru

Human factors in space telepresence

The problems of interfacing a human with a teleoperation system, for work in space are discussed. Much of the information presented here is the result of experience gained by the M.I.T. Space Systems Laboratory during the past two years of work on the ARAMIS (Automation, Robotics, and Machine Intelligence Systems) project. Many factors impact the design of the man-machine interface for a teleoperator. The effects of each are described in turn. An annotated bibliography gives the key references that were used. No conclusions are presented as a best design, since much depends on the particular application desired, and the relevant technology is swiftly changing

A Human-Embodied Drone for Dexterous Aerial Manipulation

Current drones perform a wide variety of tasks in surveillance, photography, agriculture, package delivery, etc. However, these tasks are performed passively without the use of human interaction. Aerial manipulation shifts this paradigm and implements drones with robotic arms that allow interaction with the environment rather than simply sensing it. For example, in construction, aerial manipulation in conjunction with human interaction could allow operators to perform several tasks, such as hosing decks, drill into surfaces, and sealing cracks via a drone. This integration with drones will henceforth be known as dexterous aerial manipulation. Our recent work integrated the worker’s experience into aerial manipulation using haptic technology. The net effect was such a system could enable the worker to leverage drones and complete tasks while utilizing haptics on the task site remotely. However, the tasks were completed within the operator’s line-of-sight. Until now, immersive AR/VR frameworks has rarely been integrated in aerial manipulation. Yet, such a framework allows the drones to embody and transport the operator’s senses, actions, and presence to a remote location in real-time. As a result, the operator can both physically interact with the environment and socially interact with actual workers on the worksite. This dissertation presents a human-embodied drone interface for dexterous aerial manipulation. Using VR/AR technology, the interface allows the operator to leverage their intelligence to collaboratively perform desired tasks anytime, anywhere with a drone that possesses great dexterity

Advanced Strategies for Robot Manipulators

Amongst the robotic systems, robot manipulators have proven themselves to be of increasing importance and are widely adopted to substitute for human in repetitive and/or hazardous tasks. Modern manipulators are designed complicatedly and need to do more precise, crucial and critical tasks. So, the simple traditional control methods cannot be efficient, and advanced control strategies with considering special constraints are needed to establish. In spite of the fact that groundbreaking researches have been carried out in this realm until now, there are still many novel aspects which have to be explored