Study of a Three-Groove Kinematic Coupling for Precise Positioning in a Robotized Laser-Cutting Machine

In this work, the positioning accuracy allowed by a three-groove kinematic coupling in a laser-cutting machine is studied. Kinematic couplings are designed to allow for improved accuracy and repeatability as compared to traditional elastic mediated coupling systems. A method for the estimation of positioning accuracy in a three-groove V shaped coupling is reported, and the results of the analysis carried out on a multi-purpose laser-cutting machine are presented. The results confirm that a positioning error lower than 0.02 mm is ensured by the coupling in any tested condition

The Research on Soft Pneumatic Actuators in Italy: Design Solutions and Applications

Interest in soft actuators has increased enormously in the last 10 years. Thanks to their compliance and flexibility, they are suitable to be employed to actuate devices that must safely interact with humans or delicate objects or to actuate bio-inspired robots able to move in hostile environments. This paper reviews the research on soft pneumatic actuators conducted in Italy, focusing on mechanical design, analytical modeling, and possible application. A classification based on the geometry is proposed, since a wide set of architectures and manufacturing solutions are available. This aspect is confirmed by the extent of scenarios in which researchers take advantage of such systems’ improved flexibility and functionality. Several applications regarding bio-robotics, bioengineering, wearable devices, and more are presented and discussed

Float-ram: a new human powered press for earth blocks

The Float-Ram is a novel kind of human-powered press for raw earth blocks. It is able to provide very high performance, while maintaining a limited cost, due to some technical characteristics like: •the adoption of a floating mould, which provides a bi-directional pressing action in simple way; •Optimized kinematic structure, based on a cam-roller transmission system; •General mechanical simplicity, since the node of all kinematic pairs is constituted by a single shaft. Therefore the Float-Ram can be considered as an important media for the diffusion of high-quality raw earth building in developing Countries

Parametric Identification of Postural Control Models in Humans Challenged by Impulse-Controlled Perturbations

The study of postural control system is relevant by academic and clinical points of view, and it can be improved by considering model-based approaches. In this framework, to improve the understanding of the underlying mechanism of balance control, it is often necessary to apply external perturbations to the body of a patient. This work deals with the parametric identification of postural control models by fitting with experimental data collected with a custom-made automated perturbation device. The results of model optimization are discussed and provide a preliminary validation of the methodology

A new methodology for the determination of the workspace of six-DOF redundant parallel structures actuated by nine wires

The WiRo-6.3 is a six-degrees of freedom (six-DOF) robotic parallel structure actuated by nine wires, whose characteristics have been thoroughly analyzed in previous papers in reference. It is thought to be a master device for teleoperation; thus, it is moved by an operator through a handle and can convey a force reflection on the operator's hand. A completely new method for studying the workspace of this device, and of virtually any nine-wire parallel structure actuated by wire is presented and discussed, and its results are given in a graphical for

Use of McKibben muscle in a haptic interface

One of the most relevant issues in the development of a haptic interface is the choice of the actuators that are devoted to generating the reflection forces. This work has been particularly focused on the employment of the McKibben muscle to this aim. A prototype of one finger has been realized that is intended to be part of a haptic glove, and is based on an articulated mechanism driven by a McKibben muscle. A dynamic model of the finger has been created and validated; then, it has been used to define the control algorithm of the device. Experimental tests highlighted the static and dynamic effectiveness of the device and proved that a McKibben muscle can be appropriately used in such an application

Feasibility Study of a Passive Pneumatic Exoskeleton for Upper Limbs Based on a McKibben Artificial Muscle

Exoskeletons are wearable structures or systems designed to enhance human movement and to improve the wearer’s strength or agility, providing auxiliary support aimed at reducing efforts on muscles and joints of the human body. The aim of this work is to discuss on the feasibility of a new passive upper limb exoskeleton, based on the use of pneumatic artificial muscles, and characterized by extreme lightness, cheapness, and ease of use. A broad overview of the state of the art on current exoskeletons is introduced. Then the concept of the new device is presented, and different transmission architectures between pneumatic muscle and limb are discussed. The study demonstrates the potential effectiveness of such a device for supporting an operator in heavy work condition

A passive upper-limb exoskeleton for industrial application based on pneumatic artificial muscles

In recent years, exoskeletons are increasingly spreading into the industrial manufacturing sector to improve productivity and to reduce the incidence of work-related musculoskeletal diseases. The aim of this paper is to present a 2 degrees of freedom (DoF) passive upper-limb exoskeleton, consisting of two McKibben pneumatic artificial muscles (PAMs), and used for assisting workers during activities that require them to keep their hands in a sustained position over the head for a long time. Simulations are performed to test two different commercial PAMs and two different designs of the transmission system used to convey the traction force exerted by the pneumatic muscles to the limb; then the results are discussed. A preliminary assembly of the exoskeleton is also presented. The study confirms that PAMs can be used to realize a passive upper-limb exoskeleton for industrial application and that appropriate working space can be obtained with an accurate design of the transmission system