Fabrizio Lotti

Development of UB Hand 3: Early Results

The first part of this paper describes the development of a humanoid robot hand based on an endoskeleton made of rigid links connected with elastic hinges, actuated by sheath routed tendons and covered by continuous compliant pulps. The project is called UB Hand 3 (University of Bologna Hand, 3rd version) and aims to reduce the mechanical complexity of robotic end effectors yet maintaining full anthropomorphic aspect and a good level of dexterity. In the second part this paper focuses on the early experiences of the UB Hand 3 in performing manipulation tasks.

A novel approach to mechanical design of articulated fingers for robotic hands

The paper first discusses the reasons why simplified solutions for the mechanical structure of fingers in robotic hands should be considered a worthy design goal. After a brief discussion about the mechanical solutions proposed so far for robotic fingers, a different design approach is proposed. It considers finger structures made of rigid links connected by flexural hinges, with joint actuation obtained by means of flexures that can be guided inside each finger according to different patterns. A simplified model of one of these structures is then presented, together with preliminary results of simulation, in order to evaluate the feasibility of the concept. Examples of technological implementation are finally presented and the perspective and problems of application are briefly discussed.

UBH 3: an anthropomorphic hand with simplified endo-skeletal structure and soft continuous fingerpads

The paper describes work in progress at the University of Bologna concerning the design of a new anthropomorphic robot hand. The hand is based on the modular assembly of articulated fingers that adopt an original configuration of their structure, made with rigid links connected by elastic hinges that are coaxially crossed by flexible tendons. This innovative design is suitable to host distributed sensory equipment and continuous compliant cover, allowing a high level of anthropomorphism together with great structural simplification, reliability enhancement and cost reduction. Furthermore, the proposed solution is very flexible, as it can be adapted to many different hand configurations and is not dependent on a particular type of actuation, being compatible with future availability of any kind of artificial muscles.

An innovative stand-alone bioreactor for the highly reproducible transfer of cyclic mechanical stretch to stem cells cultured in a 3D scaffold

Much evidence in the literature demonstrates the effect of cyclic mechanical stretch in maintaining, or addressing, a muscle phenotype. Such results were obtained using several technical approaches, useful for the experimental collection of proofs of principle but probably unsuitable for application in clinical regenerative medicine. Here we aimed to design a reliable innovative bioreactor, acting as a stand‐alone cell culture incubator, easy to operate and effective in addressing mesenchymal stem cells (MSCs) seeded onto a 3D bioreabsorbable scaffold, towards a muscle phenotype via the transfer of a controlled and highly‐reproducible cyclic deformation. Electron microscopy, immunohistochemistry and biochemical analysis of the obtained pseudotissue constructs showed that cells ‘trained’ over 1 week: (a) displayed multilayer organization and invaded the 3D mesh of the scaffold; and (b) expressed typical markers of muscle cells. This effect was due only to physical stimulation of the cells, without the need of any other chemical or genetic manipulation. This device is thus proposed as a prototypal instrument to obtain pseudotissue constructs to test in cardiovascular regenerative medicine, using good manufacturing procedures. Copyright

UBH3: investigating alternative design concepts for robotic hands

This paper describes the general guidelines of the development of humanoid robot hands based on design concepts that consider an endoskeleton made of rigid links connected with elastic hinges, actuated by internally routed tendons and covered by continuous compliant pulps. The project is called UBH3 (University of Bologna Hand, 3rd version) and aims to the development of hands with reduced mechanical complexity yet maintaining full anthropomorphic aspect and a good level of actual dexterity. This paper focuses on mechanical design and makes a synthetic overview of work in progress, preliminary results and open problems

Selection of linear motors for high-speed packaging machines

Specific design issues for automatic packaging machines are discussed, concerning the possible application of electric linear motors, the expected benefits and the main drawbacks. A purposely-defined software tool for the selection of these motors is then illustrated. This tool leads the designer to a systematic definition of all the parameters related to the application on high speed packaging machines and allows a step-by-step choice of the proper actuator, by means of a database where the motors available on the market have been classified and parameterized. Two application cases are then presented and discussed, related to a lifting device in a wrapping machine for home paper-products and to a mobile hot-melt glue dispenser in a box-forming machine.

Evaluating the Flexural Stiffness of Compliant Hinges Made With Close-Wound Helical Springs

Advantages and problems related to the use of compliant hinges in articulated robotic structures are briefly discussed. A novel kind of elastic joint made with close-wound helical springs is then described. It is capable of large angular displacement so that it can be conveniently applied in manipulation devices like the humanoid robot hand developed at the University of Bologna. The results of this application encourage a systematic investigation on the properties of this kind of joints, not previously described in the literature, aiming at mechanical characterization and definition of design criteria. To this purpose, the paper outlines a general investigation programme, where theoretical models, Finite Elements analysis and experiments jointly contribute to the evaluation of the hinge stiffness and to the identification of influential design parameters. Preliminary results related to evaluation of the stiffness about the principal bending axis are then examined and discussed, comparing the results obtained from experiments with those achieved by means of a simplified mathematical model and the correspondent FE analysis. An auxiliary parameter is finally introduced in order to define a general criterion for the design of spring-based hinges subjected to large deflection.© 2006 ASME

New Direction on Robotic Hands Design for Space Applications

Abstract Aim of this work is to discuss some possible solutions for the design of robotichands/grippers for space manipulation. The paper first reviews possible alternative approaches for the design of general purpose robotic end-effectors. They can differ in kinematic architecture, sensory equipment, etc. and are solutions for different needs and different application scenarios (e.g. autonomous operation, telemanipulation). Then, three examples (which have been developed at the University of Bologna) are taken into account, namely a medium complexity 3-dof robotic gripper for autonomous tasks in IVA/EVA environments, an anthropomorphic gripper for tele-operated and autonomous operations, and finally a human-like robotic hand based on new design concepts (i.e. compliant mechanisms).