Andrea Dettori

A new force-feedback arm exoskeleton for haptic interaction in virtual environments

The paper presents the mechanical design of the L-EXOS, a new exoskeleton for the human arm. The exoskeleton is a tendon driven wearable haptic interface with 5 dof 4 actuated ones, and is characterized by a workspace very close to the one of the human arm. The design has been optimized to obtain a solution with reduced mass and high stiffness, by employing special mechanical components and carbon fiber structural parts. The devised exoskeleton is very effective for simulating the touch by hand of large objects or the manipulation within the whole workspace of the arm. The main features of the first prototype that has been developed at PERCRO are presented, together with an indication of the achieved and tested performance.

Mechanical design of a novel Hand Exoskeleton for accurate force displaying

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 operators 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.

Development of a new exoskeleton for upper limb rehabilitation

This paper deals with the development of a novel exoskeleton for the robotic rehabilitation of upper extremities. The system is based on modular custom-designed actuation groups implementing high reduction ratios and redundant position measurement for securing patient safety, and joint torque sensing for guaranteeing system performance and providing application flexibility. Experimental results of the special component prototypes are reported which confirm the validity of the developed actuation groups and the potentials of the proposed exoskeleton architecture.

A versatile large-scale multimodal VR system for cultural heritage visualization

We describe the development and evaluation of a large-scale multimodal virtual reality simulation suitable for the visualization of cultural heritage sites and architectural planning. The system is demonstrated with a reconstruction of an ancient Greek temple in Messene that was created as part of a EU funded cultural heritage project (CREATE). The system utilizes a CAVE-like theatre consisting of head-tracked user localization, a haptic interface with two arms, and 3D sound. The haptic interface was coupled with a realistic physics engine allowing users to experience and fully appreciate the effort involved in the construction of architectural components and their changes through the ages. Initial user-based studies were carried out, to evaluate the usability and performance of the system. A simple task of stacking blocks was used to compare errors and timing in a haptics-enabled system with a haptics-disabled system. In addition, a qualitative study of the final system took place while it was installed in a museum.

Linear-quadratic-Gaussian torque control: Application to a flexible joint of a rehabilitation exoskeleton

A linear-quadratic-Gaussian regulator is proposed for the torque control of flexible robotic joints with built-in torque sensor. The regulator requires the joint-torque sensor information only and features: 1) a Kalman filter that, beside reducing the noise and evaluating the derivative of the torque sensor measure, is able to estimate all the external and internal torques acting on the joint; 2) a controller that optimizes system stability, responsiveness, accuracy and effort. The regulator is implemented on a flexible joint of a rehabilitation exoskeleton. Simulation and experimental results are provided which demonstrate regulator performance and efficacy.