Development of a 6 DOF Parallel Serial Hybrid Manipulator

This thesis focuses on the development of a new modular 6 DOF hybrid manipulator. A hybrid manipulator consists of the synergistic combination of serial and parallel manipulator architectures. It incorporates the good performance characteristics of a serial manipulator (larger work space and dexterity) and a parallel manipulator (higher rigidity and loading capacity/self-weight ratio). The hybrid manipulator under study includes a 3 DOF symmetric planar manipulator as a base platform over which a 3 DOF serial manipulator was placed with an appropriate endeffector. The objective of the thesis was to fabricate the above-described manipulator and develop control algorithm for manipulation. The research work started with kinematic (forward and inverse) and dynamic analysis of parallel and serial manipulators was carried analytically and computationally in MATLAB. The results of which were required for configuration selection, design optimization, motion analysis and simulation of the hybrid manipulator. From the analysis results, the planar base and serial arm manipulator was fabricated. The prototype developed was controlled in real time through MATLAB-Sim Mechanics Arduino Interface. The inverse kinematics was solved by MATLAB and servo control was established via Arduino. The algorithm developed for manipulation was verified alongside computational simulation and experiment

Dynamic modelling of hexarot parallel mechanisms for design and development

In this research, the kinematics, dynamics, and general closed-form dynamic formulation of the centrifugal high-G hexarot-based manipulators have been developed through the different mathematical modeling techniques. The vibrations of the mechanism have also been investigated

Topological analysis of a novel compact omnidirectional three-legged robot with parallel hip structures regarding locomotion capability and load distribution

In this study, a novel design for a compact, lightweight, agile, omnidirectional three-legged robot involving legs with four degrees of freedom, utilizing an spherical parallel mechanism with an additional non-redundant central support joint for the robot hip structure is proposed. The general design and conceptual ideas for the robot are presented, targeting a close match of the well-known SLIP-model. CAD models, 3d-printed prototypes, and proof-of-concept multi-body simulations are shown, investigating the feasibility to employ a geometrically dense spherical parallel manipulator with completely spherically shaped shell-type parts for the highly force-loaded application in the legged robot hip mechanism. Furthermore, in this study, an analytic expression is derived, yielding the calculation of stress forces acting inside the linkage structures, by directly constructing the manipulator hip Jacobian inside the force domain

Mechanical design and analysis of a novel three-legged, compact, lightweight, omnidirectional, serial–parallel robot with compliant agile legs

In this work, the concept and mechanical design of a novel compact, lightweight, omnidirectional three-legged robot, featuring a hybrid serial–parallel topology including leg compliance is proposed. The proposal focusses deeply on the design aspects of the mechanical realisation of the robot based on its 3D-CAD assembly, while also discussing the results of multi-body simulations, exploring the characteristic properties of the mechanical system, regarding the locomotion feasibility of the robot model. Finally, a real-world prototype depicting a single robot leg is presented, which was built by highly leaning into a composite design, combining complex 3D-printed parts with stiff aluminium and polycarbonate parts, allowing for a mechanically dense and slim construction. Eventually, experiments on the prototype leg are demonstrated, showing the mechanical model operating in the real world

A New Classification and Aerial Manipulation Q-PRR Design

International audienceThis paper presents a new designation and classification of system with UAV and robot manipulator where a new nomenclature is recognized as being the first contribution in the bibliography of design and systems. Several papers deal a problem of manipulation with a different unmanned aerial vehicle, robot arms and also with different naming of their systems, where the difficulty for locate and finding items and a good paper with its title or even by keywords, multirotor equipped with n-DoF robotic arm is the expression among the most widely used to describe that system. Aerial manipulation formula is presented and proved with a large example in the literature

Modelling and Interactional Control of a Multi-fingered Robotic Hand for Grasping and Manipulation.

PhDIn this thesis, the synthesis of a grasping and manipulation controller of the Barrett hand, which is an archetypal example of a multi-fingered robotic hand, is investigated in some detail. This synthesis involves not only the dynamic modelling of the robotic hand but also the control of the joint and workspace dynamics as well as the interaction of the hand with object it is grasping and the environment it is operating in. Grasping and manipulation of an object by a robotic hand is always challenging due to the uncertainties, associated with non-linearities of the robot dynamics, unknown location and stiffness parameters of the objects which are not structured in any sense and unknown contact mechanics during the interaction of the hand’s fingers and the object. To address these challenges, the fundamental task is to establish the mathematical model of the robot hand, model the body dynamics of the object and establish the contact mechanics between the hand and the object. A Lagrangian based mathematical model of the Barrett hand is developed for controller implementation. A physical SimMechanics based model of the Barrett hand is also developed in MATLAB/Simulink environment. A computed torque controller and an adaptive sliding model controller are designed for the hand and their performance is assessed both in the joint space and in the workspace. Stability analysis of the controllers are carried out before developing the control laws. The higher order sliding model controllers are developed for the position control assuming that the uncertainties are in place. Also, this controllers enhance the performance by reducing chattering of the control torques applied to the robot hand. A contact model is developed for the Barrett hand as its fingers grasp the object in the operating environment. The contact forces during the simulation of the interaction of the fingers with the object were monitored, for objects with different stiffness values. Position and force based impedance controllers are developed to optimise the contact force. To deal with the unknown stiffness of the environment, adaptation is implemented by identifying the impedance. An evolutionary algorithm is also used to estimate the desired impedance parameters of the dynamics of the coupled robot and compliant object. A Newton-Euler based model is developed for the rigid object body. A grasp map and a hand Jacobian are defined for the Barrett hand grasping an object. A fixed contact model with friction is considered for the grasping and the manipulation control. The compliant dynamics of Barrett hand and object is developed and the control problem is defined in terms of the contact force. An adaptive control framework is developed and implemented for different grasps and manipulation trajectories of the Barrett hand. The adaptive controller is developed in two stages: first, the unknown robot and object dynamics are estimated and second, the contact force is computed from the estimated dynamics. The stability of the controllers is ensured by applying Lyapunov’s direct method

Self-motion control of kinematically redundant robot manipulators

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2012Includes bibliographical references (leaves: 88-92)Text in English; Abstract: Turkish and Englishxvi,92 leavesRedundancy in general provides space for optimization in robotics. Redundancy can be defined as sensor/actuator redundancy or kinematic redundancy. The redundancy considered in this thesis is the kinematic redundancy where the total degrees-of-freedom of the robot is more than the total degrees-of-freedom required for the task to be executed. This provides infinite number of solutions to perform the same task, thus, various subtasks can be carried out during the main-task execution. This work utilizes the property of self-motion for kinematically redundant robot manipulators by designing the general subtask controller that controls the joint motion in the null-space of the Jacobian matrix. The general subtask controller is implemented for various subtasks in this thesis. Minimizing the total joint motion, singularity avoidance, posture optimization for static impact force objectives, which include maximizing/minimizing the static impact force magnitude, and static and moving obstacle (point to point) collision avoidance are the subtasks considered in this thesis. New control architecture is developed to accomplish both the main-task and the previously mentioned subtasks. In this architecture, objective function for each subtask is formed. Then, the gradient of the objective function is used in the subtask controller to execute subtask objective while tracking a given end-effector trajectory. The tracking of the end-effector is called main-task. The SCHUNK LWA4-Arm robot arm with seven degrees-of-freedom is developed first in SolidWorks® as a computer-aided-design (CAD) model. Then, the CAD model is converted to MATLAB® Simulink model using SimMechanics CAD translator to be used in the simulation tests of the controller. Kinematics and dynamics equations of the robot are derived to be used in the controllers. Simulation test results are presented for the kinematically redundant robot manipulator operating in 3D space carrying out the main-task and the selected subtasks for this study. The simulation test results indicate that the developed controller’s performance is successful for all the main-task and subtask objectives

Sistema de aquisição de dados por interface háptica

Mestrado em Engenharia MecânicaNeste trabalho e apresentada uma interface háptica com realimentação de força para a teleoperação de um robô humanoide é que aborda um novo conceito destinado à aprendizagem por demonstração em robôs, denominado de ensino telecinestésico. A interface desenvolvida pretende promover o ensino cinestésico num ambiente de tele-robótica enriquecido pela virtualização háptica do ambiente e restrições do robô. Os dados recolhidos através desta poderão então ser usados em aprendizagem por demonstração, uma abordagem poderosa que permite aprender padrões de movimento sem a necessidade de modelos dinâmicos complexos, mas que geralmente é apresentada com demonstrações que não são fornecidas teleoperando os robôs. Várias experiências são referidas onde o ensino cinestésico em aprendizagem robótica foi utilizado com um sucesso considerável, bem como novas metodologias e aplicações com aparelhos hápticos. Este trabalho foi realizado com base na plataforma proprietária de 27 graus-de-liberdade do Projeto Humanoide da Universidade de Aveiro (PHUA), definindo novas methodologias de comando em tele-operação, uma nova abordagem de software e ainda algumas alterações ao hardware. Um simulador de corpo inteiro do robô em MATLAB SimMechanics é apresentado que é capaz de determinar os requisitos dinâmicos de binário de cada junta para uma dada postura ou movimento, exemplificando com um movimento efectuado para subir um degrau. Ir a mostrar algumas das potencialidades mas também algumas das limitações restritivas do software. Para testar esta nova abordagem tele-cinestésica são dados exemplos onde o utilizador pode desenvolver demonstrações interagindo fisicamente com o robô humanoide através de um joystick háptico PHANToM. Esta metodologia ir a mostrar que permite uma interação natural para o ensino e perceção tele-robóticos, onde o utilizador fornece instruções e correções funcionais estando ciente da dinâmica do sistema e das suas capacidades e limitações físicas. Ser a mostrado que a abordagem consegue atingir um bom desempenho mesmo com operadores inexperientes ou não familiarizados com o sistema. Durante a interação háptica, a informação sensorial e as ordens que guiam a uma tarefa específica podem ser gravados e posteriormente utilizados para efeitos de aprendizagem.In this work an haptic interface using force feedback for the teleoperation of a humanoid robot is presented, that approaches a new concept for robot learning by demonstration known as tele-kinesthethic teaching. This interface aims at promoting kinesthethic teaching in telerobotic environments enriched by the haptic virtualization of the robot's environment and restrictions. The data collected through this interface can later be in robot learning by demonstration, a powerful approach for learning motion patterns without complex dynamical models, but which is usually presented using demonstrations that are not provided by teleoperating the robots. Several experiments are referred where kinesthetic teaching for robot learning was used with considerable success, as well as other new methodologies and applications with haptic devices. This work was conducted on the proprietary 27 DOF University of Aveiro Humanoid Project (PHUA) robot, de ning new wiring and software solutions, as well as a new teleoperation command methodology. A MATLAB Sim- Mechanics full body robot simulator is presented that is able to determine dynamic joint torque requirements for a given robot movement or posture, exempli ed with a step climbing application. It will show some of the potentialities but also some restricting limitations of the software. To test this new tele-kinesthetic approach, examples are shown where the user can provide demonstrations by physically interacting with the humanoid robot through a PHANToM haptic joystick. This methodology will show that it enables a natural interface for telerobotic teaching and sensing, in which the user provides functional guidance and corrections while being aware of the dynamics of the system and its physical capabilities and / or constraints. It will also be shown that the approach can have a good performance even with inexperienced or unfamiliarized operators. During haptic interaction, the sensory information and the commands guiding the execution of a speci c task can be recorded and that data log from the human-robot interaction can be later used for learning purposes

A Design for Proprioceptive Force in 3D Agility Robot Through Use of AI

For robots to be considered effective, they should be able to maneuver through 3D environments. To achieve such mobility, robots needs to be designed in such a way that would span various topographies. So, artificial intelligence algorithms have been developed to ensure agility of the robots when walking on murky topographies. In the current state of the art legged robots, there is still much progress need to be made in research to turn them into automobiles with great agility to be used in the real world utility and provide mobility in rough. GOAT leg as a means of artificial intelligence is still a new phenomenon. There still exists a number of preliminary tests that need to be done in accessing and in the characterization of the leg’s current performance and its implications in the future. This study seeks to develop and agility model which would be useful in ensuring that the robots remain agile in such complex environments. To do this, a simulation has been through Matlab analysis. Results of the current study showed that, 3-RSR was designed to ensure that a high fidelity proprioceptive force control would enable legs with the mechanically spring stiffness. Implications and future recommendations also discussed