Human stance in quiet mode, relies on feedback from eyes, skin, muscles and the inner ear and the control produced is a combination of strategies which enable a person to stay standing. This thesis presents the simulation and control of a hip actuated robotic model of human standing posture. / The first part of the thesis is devoted to recalling basic elements of the human balance system and to describe the balance strategies it uses to maintain an upright stance. Of the strategies presented, we consider the hip strategy which motivated the formulation of a hip actuated robot. An investigation into the control of nonlinear underactuated robots by linear controllers is done to verify the range and efficiency of the controlled system. / The second part of the thesis includes the investigation of two simplified models of the robot. Results using linear state feedback control are presented. The two models used are compared to clarify the use of one over the other. / We found that for linear controls, the size of the region of convergence decreased underactuated systems of increasing complexity. For our four degrees of freedom robot, the region of convergence is of 2.3 degrees for the actuated joints and of 1 degree for the unactuated joints. Our system is Lyapunov stable when the fully simplified model is assumed.

The ability of robotic units to navigate various terrains is critical to the advancement of robotic operation in real world environments. Next generation robots will need to adapt to their environment in order to accomplish tasks that are either too hazardous, too time consuming, or physically impossible for human-beings. Such tasks may include accurate and rapid explorations of various planets or potentially dangerous areas on planet Earth. This research investigates a navigation control methodology for a wheel-legged robot based on active vision. The method presented is designed to control the reconfigurability of the robot (i.e. control the usage of the wheels and legs), depending upon the obstacle/terrain, based on perception. Surface estimation for robot reconfigurability is implemented using a region growing method and a characterization and traversability assessment generated from camera data. As a result, a mathematical approach that directs necessary navigation behavior is implemented to control robot mobility. The hybrid wheeled-legged rover possesses a four-legged or six-legged walking system as well as a four-wheeled mobility system.

Thesis (Ph.D)--Computing, Georgia Institute of Technology, 2009. / Committee Chair: Dellaert, Frank; Committee Member: Bobick, Aaron; Committee Member: Christensen, Henrik; Committee Member: Leonard, John; Committee Member: Rehg, James. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2008. / Robot control by TCP/IP communication is investigated in this thesis for existing robots used in tertiary education. The request for newer software for robotic computer control came from the University of Stellenbosch Industrial Engineering department where existing software dating back to 1988 is still in use. A thorough investigation into the research and technologies available is followed by a discussion on the proposed software to adhere to the requirement of compatibility with existing languages in use by the department and provide tools to assist in future research in robotic manipulators and control. The proposed software solution uses a client/server model running over an IP-based network providing online and offline programming with visual feedback by means of video streaming and 3D simulations, developed as separate modules combined into an effective tool for future research and development.

Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: This project, tided An Integrated Control System for the SubsetJ of a Mobile Robot, concerns the integration of subsets for a mobile robotic system developed in the past. It was found that these subsets would not integrate with ease and that integration was not taken into account when the subsets were developed. The complete problem statement is given in chapter one. Before trying to solve the problem the author did a literature review to eqwp her with the necessary knowledge and skills needed to solve the problem. The literature reviewed included topics like Computer Integrated Manufacturing (CIM) and Mobile Robotic. A thorough study of the developed subsets was also completed. The proposed control system is software-based and developed in three programming languages: e TURBO PASCAL, e BORLAND DELPHI, and :> MA1LAB. The DELPHI and MATLAB programs run on the base station. This computer communicates with the MOBile ROBot used in this project (MOBROB) using RF communication hardware and software. This software is part of the DELPHI programs. The DELPHI program is the starting point. This program then calls the MATLAB programs or sends data to the robot. It is important to set the hardware as prompted. The process basically consists of creating path files on the base station. These files are then sent to the robot. The robot then drives to a destination, updates its position and sends the new position back to the base station. The onboard programs used by the robot were developed in TURBO PASCAL. These programs are responsible for the control of the robot's hardware. The control system is discussed in detail in chapters five, sUtand seven. The project was completed successfully and all the objectives set at the beginning of the project were met. These objectives are given in chapter one. This document consists of four sections. The first section is the introduction, the second section the literature review, the third section discusses the control system and the fourth section discusses the results and contains conclusions and recommendations. / AFRIKAANSE OPSOMMING: Die projek, getiteld 'n Geïntegreerde beheerstelselvir die subdek van 'n Mobiele Rabot, handel oor die integrasie van voorafontwikkelde dele vir 'n mobiele robotiese stelsel. Daar is gevind dat die dele nie maklik is om te integreer nie en dat integrasie glad nie in ag geneem is toe die dele ontwikkel is nie. Die volledige probleemstelling word in hoofstuk een gegee. Voordat die probleem aangepak is, is 'n literatuurstudie voltooi om die skrywer toe te rus met die kennis wat nodig is vir die oplos van die probleem. Die literatuurstudie het gehandel oor Rekenaar-geïntegreerde vervaardiging (CIM), mobiele robotte en die verskillende voorafontwikkelde dele van die stelsel. Die literatuurstudie vorm hoofstukke twee, drie en vier van hierdie dokument. Die voorgestelde beheerstelsel is sagteware gebaseer en is in drie rekenaar programmerings-tale ontwikkel: ~ TURBO PASCAL, e BORLAND DELPHI en ~ MA1LAB. Die DELPHI and MA1LAB programme loop op die beheerstasie rekenaar. Die rekenaar kommunikeer met die robot deur middel van RF kommunikasie hardeware en sagteware. Hierdie sagtware vorm deel van die DELPHI sagteware. Daar word begin by die Delphi program. Die program roep dan die MATLAB programme op of stuur data na die robot toe. Dit is belangrik om die apparatuur op te stel soos in die dokument aangeteken is, voor die programme geloop word. Die proses bestaan basies uit die skep van pad-lêers op die beheerstasie. Hierdie lêers word dan na die robot gestuur, wat van sy huidige posisie na 'n bestemming toe beweeg. Wanneer die taak voltooi is, word die nuwe posisie van die robot teruggestuur na die beheerstasie. Op die robot self, loop die PASCAL program, wat verantwoordelik is vir die beheer van die robot hardeware. Die beheerstelsel word deeglik bespreek in hoofstukke vyf, ses en sewe. Die projek is suksesvol afgehandel en daar word aan al die doelstellings wat aan die begin van die projek daar gestel is, voldoen. Hierdie doelstellings word in hoofstuk een gegee. Die verslag bestaan uit vier dele. Die eerste deel is 'n inleiding, die tweede deel 'n literatuurstudie, die derde deel bespreek die beheerstelsel en die vierde deel is 'n samevatting waar die resultate bespreek word en gevolgtrekkings en aanbevelings gemaak word.

Orientadores: Helder Anibal Hermini, Jose Manoel Balthazar / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Meêanica / Made available in DSpace on 2018-08-04T10:09:17Z (GMT). No. of bitstreams: 1 Pires_LeoSantana_M.pdf: 9313372 bytes, checksum: a9469afaba08752e7ef419dc781fe926 (MD5) Previous issue date: 2005 / Resumo: Uma aproximação unificada para projeto e controle de manipuladores robóticos que retenha todas as não linearidades inerentes na dinâmica é desenvolvido para uma configuração robô-motor considerado como um sistema interagente. Este projeto de sistema interagente, baseado no modelo de teoria de controle de desacoplagem não-linear de Beekmann, desacopla a configuração robô-motor para os subsistemas robô, motor e interação cm série. Esta aproximação está em contraste ao tratamento convencional do motor como uma pura fonte dc torque c o negligenciamento da interação dinâmica entre a junta do robô e o motor, e ao desconsiderar a formulação não-linear / Abstract: A unified approach to a robotic controI design, which retains all the nonlinearities inherent in the dynamics, is developed for the motor-robot configuration considered as an imeracting system. This control system design, based on the Beekmann model's nonlinear decoupling control theory with arbitrary pole placement, decouples the motor-robot configuration into robot, motor, and series compliance (interaction) subsystems. This approch is in contrast to the conventional treatment of the motor as apure torque source and the neglect of dynamic interactions between the robot joint and the motor drive mechanism and not consider the nonlinear formulation / Mestrado / Projeto Mecanico e Mecanica dos Solidos / Mestre em Engenharia Mecânica

D.Ing. / A simulation system of an industrial robot, within a manufacturing environment for its intelligent interaction within the cell as well as its control via the Internet is presented. The simulation verification in an experimental cell in which an ABB lRB 2400 robot operates is discussed. Sensors employed throughout the cell to supply the input for robot action through an expert system are described. The robot interacts with several task groups of the cell, production equipment, materials handling and assembly. The cell use of a PC, directly linked to the robot and other equipment and sensors for, cell control is explained. The PC has full on-line control of all equipment while the simulation runs simultaneously with the experimental set-up. The system incorporates robot and cell control via the Internet. To add additional intelligence to the cell a transponder system, tagging each part in the robotic cell, is also implemented. This enables each part to be identified by the robot, as well as for the robot to interact with each transponder.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering in the Control Research Group School of Electrical and Information Engineering, Johannesburg, 2017 / In this research, we observed a torque-related limitation in the swing-up control of underactuated mechanical systems which had been integrated with viscous damping in the unactuated joint. The objective of this research project was thus to develop a practical work-around solution to this limitation. The nth order underactuated robotic system is represented in this research as a collection of compounded pendulums with n-1 actuators placed at each joint with the exception of the first joint. This system is referred to as the PAn-1 robot (Passive first joint, followed by n-1 Active joints), with the Acrobot (PA1 robot) and the PAA robot (or PA2 robot) being among the most well-known examples. A number of friction models exist in literature, which include, and are not exclusive to, the Coulomb and the Stribeck effect models, but the viscous damping model was selected for this research since it is more extensively covered in existing literature. The effectiveness of swing-up control using Lyapunov’s direct method when applied on the undamped PAn-1 robot has been vigorously demonstrated in existing literature, but there is no literature that discusses the swing-up control of viscously damped systems. We show, however, that the application of satisfactory swing-up control using Lyapunov’s direct method is constrained to underactuated systems that are either undamped or actively damped (viscous damping integrated into the actuated joints only). The violation of this constraint results in the derivation of a torque expression that cannot be solved for (invertibility problem, for systems described by n > 2) or a torque expression which contains a conditional singularity (singularity problem, for systems with n = 2). This constraint is formally summarised as the matched damping condition, and highlights a clear limitation in the Lyapunov-related swing-up control of underactuated mechanical systems. This condition has significant implications on the practical realisation of the swing-up control of underactuated mechanical systems, which justifies the investigation into the possibility of a work-around. We thus show that the limitation highlighted by the matched damping condition can be overcome through the implementation of the partial feedback linearisation (PFL) technique. Two key contributions are generated from this research as a result, which iii include the gain selection criterion (for Traditional Collocated PFL), and the convergence algorithm (for noncollocated PFL). The gain selection criterion is an analytical solution that is composed of a set of inequalities that map out a geometric region of appropriate gains in the swing-up gain space. Selecting a gain combination within this region will ensure that the fully-pendent equilibrium point (FPEP) is unstable, which is a necessary condition for swing-up control when the system is initialised near the FPEP. The convergence algorithm is an experimental solution that, once executed, will provide information about the distal pendulum’s angular initial condition that is required to swing-up a robot with a particular angular initial condition for the proximal pendulum, along with the minimum gain that is required to execute the swing-up control in this particular configuration. Significant future contributions on this topic may result from the inclusion of more complex friction models. Additionally, the degree of actuation of the system may be reduced through the implementation of energy storing components, such as torsional springs, at the joint. In summary, we present two contributions in the form of the gain selection criterion and the convergence algorithm which accommodate the circumnavigation of the limitation formalised as the matched damping condition. This condition pertains to the Lyapunov-related swing-up control of underactuated mechanical systems that have been integrated with viscous damping in the unactuated joint. / CK2018

No description available.

This thesis mainly consists of five independent papers concerning the reactive control design of autonomous mobile robots in the context of target tracking and cooperative formation keeping with obstacle avoidance in the static/dynamic environment. Technical contents of this thesis are divided into three parts. The first part consists of the first two papers, which consider the target-tracking and obstacle avoidance in the static environment. Especially, in the static environment, a fundamental issue of reactive control design is the local minima problem(LMP) inherent in the potential field methods(PFMs). Through introducing a state-dependent planned goal, the first paper proposes a switching control strategy to tackle this problem. The control law for the planned goal is presented. When trapped into local minima, the robot can escape from local minima by following the planned goal. The proposed control law also takes into account the presence of possible saturation constraints. In addition, a time-varying continuous control law is proposed in the second paper to tackle this problem. Challenges of finding continuous control solutions of LMP are discussed and explicit design strategies are then proposed. The second part of this thesis deals with target-tracking and obstacle avoidance in the dynamic environment. In the third paper, a reactive control design is presented for omnidirectional mobile robots with limited sensor range to track targets while avoiding static and moving obstacles in a dynamically evolving environment. Towards this end, a multiiii objective control problem is formulated and control is synthesized by generating a potential field force for each objective and combining them through analysis and design. Different from standard potential field methods, the composite potential field described in this paper is time-varying and planned to account for moving obstacles and vehicle motion. In order to accommodate a larger class of mobile robots, the fourth paper proposes a reactive control design for unicycle-type mobile robots. With the relative motion among the mobile robot, targets, and obstacles being formulated in polar coordinates, kinematic control laws achieving target-tracking and obstacle avoidance are synthesized using Lyapunov based technique, and more importantly, the proposed control laws also take into account possible kinematic control saturation constraints. The third part of this thesis investigates the cooperative formation control with collision avoidance. In the fifth paper, firstly, the target tracking and collision avoidance problem for a single agent is studied. Instead of directly extending the single agent controls to the multiagents case, the single agent controls are incorporated with the cooperative control design presented in [1]. The proposed decentralized control is reactive, considers the formation feedback and changes in the communication networks. The proposed control is based on a potential field method, its inherent oscillation problem is also studied to improve group transient performance.