This paper describes the design, the preliminary evaluation and proposes a control strategy of a novel distributed tactile transducer for finger tip stimulation. The presented study has been conducted for the realization of a compact tactile device aiming at integration with a kinesthetic feedback systems. The transducer is a 5×6 array based on custom electromechanical mini-solenoid designed and optimized for reduced encumbrance and lightweight. The realized actuator has a diameter of 2.4mm and is capable of delivering a maximum force of 73mN. In the first section we present the electro-mechanical design, the optimization and the first experimental test of a prototype for the new transducer. In the second section we show the electronic design and a strategy for controlling arrays of transducers with a reduced number of connectors. This principle is based on active matrix addressing of LCD displays.

The PERCRO laboratory of Scuola Superiore Sant'Anna has recently completed the development and functional assessment of the Body Extender (BE) system, an advanced wearable robot expressly conceived for augmenting the human strength for handling of heavy materials in unstructured environment. The system is composed by four robotic limbs with anthropomorphic kinematics and has a total of 22 independently actuated degrees of freedom. The leg locomotion and the force servo-amplification allow operations in environments that are hardly accessible by the conventional handling systems preserving the force sensibility during the manipulative tasks. Possible applications are handling of military materials in narrow spaces, rescuing of victims in natural and human provoked disasters and handling of heavy parts in the manufacturing of large products. The paper reports the system specifications taken as a reference for the design, the criteria and verification methods, the architectural solutions used for the implementation of mechanics, electronic and control components and the results of the preliminary experimental assessment.

Advanced robotics needs a new breed of actuators, capable to exhibit a large number of desirable features, ranging from high power/torque density, high efficiency, zero backlash and low noise, to low reflected mechanical impedance, high bandwidth and accuracy. Even if it is quite evident that to fully match these requirements new basic actuation principles have to be investigated and developed in the long term, there is still scope now for innovating the field by combining mature components into new actuation schemes. This paper reports the development and the experimental evaluation of a new actuator, aiming at improving the torque density and the mechanical efficiency. The device has shown impressive performances being able to exert up to 500Nm continuous torque and 800Nm peak torque with 85% mechanical efficiency and zero backlash, up to 60°/s maximum output speed for a total weight of just 6Kg, comprising the structural case covering the internal mechanics. The actuator has been expressly conceived as an actuation module to be integrated in a fully powered whole body exoskeleton intended for material handling in tight and unstructured environments (see Fig.1).

This paper deals with the mechanical and control design of an exoskeletric power extender for the whole human body. A critical issue in the design of such kid of devices is granting a sufficient level of transparency. The authors propose two design conditions based on tracking force threshold and equilibrium considerations that should be complied. This methodology has been applied to the specific design of a body extender for material handling that is currently being developed at the PERCRO (PERceptual RObotics) Lab of Scuola Superiore S. Anna of Pisa, Italy.

This paper deals with the mechanical design of a novel haptic hand exoskeleton (HE) that allows exerting controlled forces on the fingertip of the index and thumb of the operator. The proposed device includes several design solutions for optimizing the accuracy and mechanical performances. Remote centers of motion mechanisms have been adopted for delocalizing the encumbrance of linkages of the structure away from the operator's fingers. An improved stiffness of the transmission and reduced requirements for the actuators have been achieved thanks to a novel patent pending principle for integrating speed reduction ratio with the transmission system.

This paper describes the design, the development and the tests of an innovative 6 degrees of freedom (DoFs) mechanical tracker. The new device has a modular structure that exploits three mechanical units each composed of two rotational joints and allows to scale the usable workspace by substituting the connecting links. The sensing principle for the joint angles measurement is based on an innovative hall-effect angle sensor with high resolution, developed and conceived for low cost applications. The system that has been realized and tested is conceived for the tracking of portable haptic devices. Furthermore, the system includes a weight balancing system that allows to exploit the mechanical structure of the tracker for balancing a given weight located at the end-effector of the device.

This paper presents the results of a clinical trial employing the PERCRO L-Exos (Light-Exoskeleton) system, which is a 5-DoF force-feedback exoskeleton for the right arm, for robotic-assisted rehabilitation. The device has demonstrated itself suitable for robotic arm rehabilitation therapy when integrated with a Virtual Reality (VR) system. Three different schemes of therapy in VR have been tested in the clinical evaluation trial, which was conducted at the Santa Chiara Hospital in Pisa with nine chronic stroke patients. The results of this clinical trial, both in terms of patients performance improvements in the proposed exercises and in terms of improvements in the standard clinical scales which have been used to monitor patients progresses will be reported and discussed throughout the paper. It is to be noted that statistically significant improvements have been demonstrated in terms of Fugl-Meyer scores, Ashworth scale and increments of active and passive ROMs on shoulder, elbow and wrist joints of the impaired limb.

The EU funded RTD project "HAPTEX" addresses the challenge of developing a Virtual Reality (VR) system for the realistic and accurate rendering of the physical interactions of humans with textiles, through the real-time generation of artificial visual and haptic stimuli. This challenge concerns the development of both the SW and the HW components of the VR system, as well as it implies a substantial advancement in the understanding of the mechanisms underlying the human haptic perception of fine physical properties like those of textiles. This paper reports some important details relating to the technical implementation of the developed HW and SW components with special emphasis on the issues related to their integration into a single VR system. Furthermore some preliminary results relating to the functional tests carried out on the integrated system are also reported.

This paper presents the synthesis and the analysis of the kinematics of a new robotic parallel wrist for laparoscopic surgery applications. The main properties of this new wrist are the wide singularity free orientation workspace and the capability of making large rotations of the end-effector with small rotation of the actuators. First, it is shown how these features suit the application of minimally invasive surgery. Secondly, the kinematics is described showing its working principle that allows the achievement of rotation multiplication. The forward kinematics problem is solved geometrically. Afterwards, a methodology based on screw theory for the solution of the differential kinematics is proposed. Finally a workspace representation is presented making a comparison with another known parallel wrist

This paper describes the results of the design of the actuation system of the MORIS two-wheeled vehicle simulator for motorcycle design and development. Firstly, a general overview of the simulator is shown. Secondly, the description of the strategy manager and of the software design tool is reported. Finally, the numeric results of the basic design manoeuvres and of the overall simulator are described.

The control of exploratory and manipulative procedures in teleoperation and virtual environments requires the availability of adequate advanced interfaces capable not only of recording the movements of the human hands and arms, but also of replicating sensations of contact and collisions. In this paper the problem of replicating external forces acting against the remote/virtual arm is addressed. The design of an arm exoskeleton system developed in the authors' laboratory is presented. The exoskeleton consists of a 7 DOF actuated and sensorized mechanical structure wrapping up completely the human arm and directly supported by the shoulders and the trunk of the human operator. Emphasis is given to the implemented control procedures and to the description of the transputer-based control architecture.>

A push-pull actuator for commanding the motion of the interphalangeal joints of anthropomorphic robotic hands is proposed. The actuator, based on coil springs, made of the shape-memory alloy Nitinol, is compact enough to be easily incorporated into the phalangeal structure of a robotic finger, thus eliminating the complex routing of the cables and tendons usually adopted for transmitting motion from conventional actuators (e.g. DC servomotors) to the joints. The performance of the SMA actuator is illustrated, and the concepts of temperature, strain, and stress limits for the control of the whole push-pull actuating system are emphasized. The methods adopted to improve the usually limited frequency response of SMA actuators are also described. Finally, the control of the whole system and some experimental results demonstrating promising actuator performance are discussed.>