Development of an anthropomorphic robot hand and wrist for teleoperation applications

In this work, we are developing an anthropomorphic robot hand and wrist to be teleoperated by a human using a glove input device. The present model of the hand is intended for use in grasping operations, and consists of a palm, two fingers, an opposed thumb, and two wrist joints that provide pitch and roll movements. Each of the three digits of the robot hand has two pitch joints to enable flexion and extension, and incorporates a new passive switching mechanism that allows a single actuator to drive the two joints successively. The hand/wrist system has a total of five independent degrees-of-freedom. It is driven by five remotely located DC motors through servo control, and the drive from the motors is transmitted to the hand and wrist joints through flexible sheathed cables acting as tendons. The work focuses on replicating as closely as possible the shape, size, natural motions and applied forces of the human appendage, while keeping the complexity of the robot hand and wrist to a minimum. The first prototype of the hand has been demonstrated, and is capable of holding a wide variety of objects of different shapes and sizes using both precision-type and power-type grasp configurations.peer-reviewe

Systematic gripper arrangement for a handling device in lightweight production processes

Handhabungsgeräte sind ein integraler Bestandteil automatisierter Produktionsprozesse. Dennoch werden sie in der Regel als nicht wertschöpfend angesehen, weshalb ihre Planung und Projektierung mit geringem Zeit- und Personalaufwand so effektiv wie möglich sein sollte. Gleichzeitig bleiben sie ein wichtiger Teil der Prozesskette und müssen in diesem Zusammenhang bestimmte Bedingungen erfüllen. Um ihre Funktionalität zu gewährleisten und wenig Zeit in die Projektierung zu investieren, sind Handhabungsgeräte oft überdimensioniert. Insbesondere bei flachen Teilen führt dies zu schweren Handhabungslösungen, bei denen das Gewicht des Handhabungsobjekts und des Handhabungsgerätes in einem Missverhältnis zueinander stehen. Ziel der vorliegenden Arbeit ist es, die Projektierung von Handhabungsgeräten so weit wie möglich zu automatisieren. Dieser Prozess wird am Beispiel der Prozesskette zur Herstellung von Leichtbauteilen mit den Verfahren „sheet molding compound“ (SMC) und „resin transfer molding“ (RTM) dargestellt. In einem ersten Schritt wird ein modulares Handhabungsgerät entwickelt und aufgebaut, das eine große Anzahl von Greiferanordnung ermöglicht. Mit diesem Handhabungsgerät kann dann die resultierende Durchbiegung von flachen Bauteilen mit verschiedenen Greiferanordnungen gemessen werden. Um sicherzustellen, dass es nicht immer notwendig ist die Durchbiegungen zu messen, wird mit ABAQUS ein Modell aufgebaut, das eine Simulation der Durchbiegung ermöglicht. Anhand dieses Simulationsmodells wird eine Designlogik für die Anordnung der Greifer entwickelt. Diese Designlogik arbeitet in zwei Schritten und basiert auf dem Ansatz des „growing neural gas“ (GNG), das durch die Implementierung zusätzlicher Regeln an das Problem angepasst wird. Zuerst wird eine erste Greiferkonfiguration basierend auf der Geometrie des Objekts erstellt, die dann durch einen iterativen Prozess aus Simulation und Anpassung verbessert wird. Da die Herstellung von Leichtbauteilen oft mehr als nur einen Zuschnitt erfordert, werden am Ende systematisch verschiedene Lösungen für die verschiedenen Zuschnitte zu einer Greiferanordnung zusammengefasst und ein Verfahren gezeigt, wie dies ,mit dem zuvor entwickelten modularen Handhabungsgerät realisiert, werden kann

Development of a modular reconfigurable machine for reconfigurable manufacturing systems.

M. Sc. Eng. University of KwaZulu-Natal, Durban 2010.The Reconfigurable Manufacturing Systems (RMSs) paradigm has been formulated to encapsulate methodologies that enable manufacturing systems to effectively cope with changes in markets and products. RMSs are systems which are envisioned to be capable of a rapid change in manufacturing layouts, process configurations, machines and control components to provide a quick response to changes in the master production schedule. This research was initiated due to the necessity for new forms of production machinery to be design for RMSs, which can aid manufacturers in the adjustment of system capacity and functionality at lower costs. This thesis presents the development of Modular Reconfigurable Machines (MRMs), as a novel machining solution within the scope of RMSs. MRMs are characterized by modular mechanical structures that enable the flexibility of the machine to be adjusted in response to changes in products. The concept of adjustable flexibility implies that the flexibility of the machines may be balanced to exactly match the requirements of the system when changes in production plans occur. Product changes are managed by a variation of machining processes and Degrees of Freedom (DOF) on a platform. The modular nature of these machines permits this to be done easily and cost effectively. MRMs therefore possess an advantage over traditional machining systems, where an adjustment of system functionality would require the procurement of new machinery. Manufacturers will also have the option to purchase machines with flexibility that may be increased as needed, instead of investing in highly flexible and expensive CNC systems, with features that are often excessive and unused. Main points of this research included the development of mechanical modules for assembly into complete machines. The number and types modules used in an assembly could be changed to provide the kinematic and process optimization of the mechanical hardware according to production requirements. In conjunction to the mechanical development, a suitable Mechatronic control system will be presented. The focus of control development was the facilitation of seamless system integration between modular mechanical hardware and the controller at both hardware and software levels. The control system is modular and distributed and characterised by a “plug-in” approach to control scalability. This is complimented by a software architecture that has been developed with a focus on hardware abstraction for the management of a reconfigurable mechanical and electronic architecture. A static and dynamic analysis of the MRM system is performed for a selected mechanical configuration. The performance of the mechanical and control system is also evaluated for static and dynamic positioning accuracy for different modes of motion control. The implications for MRMs are then analysed, which include system functionality and capacity scaling, manufacturing expansion flexibility and system life spans. The research was concluded with an analysis of the challenges and problems that must be addressed before MRMs become industrially acceptable machines

Design fundamentals of a reconfigurable robotic gripper system

Summarization: Discusses the design and modeling fundamentals of a multi-degree-of-freedom reconfigurable robotic gripper system (RGS), designed to automate the process of limp material handling, reliably and without distortion, deformation, and/or folding. The reconfigurable gripper design draws upon a previously reported flat surfaced, fixed-dimensions gripper system (Kolluru et al., 1998). The design consists of four arms in a cross-bar configuration, with a flat surfaced, fixed dimensions, suction-based gripper unit mounted on each of the arms. The kinematic and dynamic performance of the reconfigurable RGS is analyzed theoretically and then validated using Integrated Design Engineering Analysis Software (I-DEAS) simulation softwarePresented on: IEEE Transactions on Systems, Man and Cybernetics, Part A: Systems and Human