Benedetto Allotta

Robotics for medical applications

The authors review the most important past and ongoing research projects in macro-robotics, micro-robotics and bio-robotics, three general areas of robotics which have the potential to provide significant improvements to the state of the art of medical technology. A brief analysis of the economic potentialities of robotics in medicine is also provided.

Mousebuster: a robot for real-time catching

A control methodology for catching a fast moving object with a robot manipulator, where visual information is employed to track the trajectory of the target, is described here. Sensing, planning, and control are performed in real time to cope with possible unpredictable trajectory changes of the moving target, and prediction techniques are adopted to compensate the time delays introduced by visual processing and by the robot controller. A simple but reliable model of the robot controller has been taken into account in the control architecture for improving the performance of the system. Experimental results have shown that the robot system is capable of tracking and catching an object moving on a plane at velocities of up to 700 mm/s and accelerations of up to 1500 mm/s/sup 2/.<<ETX>>

Image-based visual servoing of nonholonomic mobile robots

In this paper, a novel image-based visual approach for the position control of a nonholonomic mobile robot is presented. The mobile robot is endowed with a fixed camera, and visual feedback is used to control the robot pose with respect to a rigid object of interest. After introducing a three dimensional state space representation of the camera-object visual interaction model fully defined in the image plane, a closed-loop stabilizing control law is designed, based on Lyapunovs direct method. The image-based control scheme, which uses a discontinuous change of coordinates, ensures global asymptotic stability of the closed-loop visual system. Moreover, in the case of known height of the object, global stability is formally proved using an adaptive control law. Experimental results obtained with a tank model validate the framework, both in terms of system convergence and control robustness.

A hand-held drilling tool for orthopedic surgery

A novel hand-held drilling tool devoted to orthopedic surgery is presented in this paper. The starting point of the study is the conjecture that the invasiveness of interventions might be reduced by adding sensing, reasoning, and control capabilities to existing tools, in order to obtain controlled penetration in the patients body and automatic discrimination among layers of different tissues. Due to the particular environment in which the tool is to work, the requirements in terms of human friendliness and safety impose a careful design of the human-machine interface. The proposed approach to the development of a mechatronic tool for surgery is discussed, with emphasis on the functionality and performance of the device and the limited-usage expertise required. New applications for the proposed concepts in nonsurgical environments requiring hand-held tools are foreseen.

Study on a mechatronic tool for drilling in the osteosynthesis of long bones : Tool/bone interaction, modeling and experiments

Among the few motorized procedures used in orthopaedic surgery, drilling is surely the most common. Current drilling tools do not include any means for the control of the penetration and only radiographic control and/or a surgeons manual skill are used to arrest the penetration of the drill when the hole is completed. Late detection of bone/soft tissue breakthroughs can cause unnecessary damage to the patient. New mechatronic drills making use of cutting force information could be used to assist the surgeon during the intervention. The goal of the experimental study reported is to develop and validate experimentally a model for the description of breakthroughs during the penetration of long bones. Such a model can be used for real-time detection of breakthroughs and be included in a mechatronic drill. Experimental results of drilling trials on fresh animal long bones are presented.

Preliminary design and fast prototyping of an Autonomous Underwater Vehicle propulsion system

The Mechatronics and Dynamic Modelling Laboratory of the Department of Industrial Engineering, University of Florence, as a partner of THESAURUS (Italian acronym for ‘TecnicHe per l’Esplorazione Sottomarina Archeologica mediante l’Utilizzo di Robot aUtonomi in Sciami’) project, has developed an innovative low-cost, multirole autonomous underwater vehicle, called Tifone. This article deals with the adopted methodologies for the autonomous underwater vehicle design: in particular, the main focus of this study is related to its propulsion system. According to the expected performances and requirements of THESAURUS project, the vehicle has to maintain good autonomy and efficiency (typical features of an autonomous underwater vehicle), with high manoeuvrability and hovering capabilities, which are more common of remotely operated vehicles. Moreover, cooperative underwater exploration and surveillance involve the use of a swarm of vehicles. In particular, the optimization of costs versus benefits is achieved through the design of a fleet of three multirole vehicles. Each autonomous underwater vehicle has five controlled degrees of freedom, thanks to four thrusters and two propellers: in this article, the preliminary design criteria concerning the vehicle and the design and testing of its actuation system are described.

Robotics in medicine

This paper reports the current state-of-the-art in medical robotics. Three general areas of advanced robotics are identified: macro robotics, micro robotics and bio-robotics. Macro robotics include the development of robots, wheelchairs, manipulators for rehabilitation as well as new more powerful tools and techniques for surgery. Micro robotics could contribute to the field of minimally invasive surgery as well as to the development of a new generation of miniaturised mechatronic tools for conventional surgery. Bio-robotics deals with the problems of modelling and simulating biological systems in order to provide a better understanding of human physiology. According to this classification, a review on the most important past and ongoing research projects in the field is reported. Some commercial products already appeared on the marker are also mentioned, and a brief analysis of the economical potentialities of robotics in medicine is presented.<<ETX>>

Design and Experimental Results of an Active Suspension System for a High-Speed Pantograph

In high-speed trains, current collection from the overhead line is assured by an articulated suspension system called the dasiadasiapantographpsilapsila Contact wires and overhead line are flexible systems that are subjected to oscillations that have to be compensated for a satisfactory quality of current collection. In high-speed railway applications, this technical problem is very important since higher traveling speed involves higher oscillations of the catenary. A feasible solution to improve current collection quality is to optimize the dynamical response of the pantograph suspension system through an active or semiactive suspension system. The authors of this paper have worked and cooperated with a team composed of members of Trenitalia SPA (main Italian railway company), Ital-certifer (an Italian R&D agency), and many Italian Universities (Universita di Firenze, Politecnico di Milano, Universita di Pisa, and Universita di Napoli) to the development of a prototype of an innovative railway pantograph for Italian high-speed lines. The authors have designed the layout of the control system (actuation system, sensors, drive and control algorithm, etc.). The proposed control strategy has been successfully calibrated with experimental tests. Testing procedures and experimental results are shown in order to demonstrate the feasibility of the proposed solution and performances achieved by the first Trenitalia prototype, the T2006 pantograph.

Image-based robot task planning and control using a compact visual representation

We present an approach for the design and control of both reflexive and purposive visual tasks. The approach is based on the bidimensional appearance of the objects in the environment and explicitly takes into account independent object motions. A linear model of camera-object interaction is embedded in the control scheme, which dramatically simplifies visual analysis and control by reducing the size of visual representation. We describe the implementation of three visual tasks of increasing complexity, obtained with the proposed scheme and based on the active contour analysis and polynomial planning of image contour transformations. Both simulations and real-time experiments with a robotic eye-in-hand configuration are discussed, validating the approach in terms of robustness and applicability to visual navigation, active exploration and perception, and human-robot interaction.

Cooperative localization of a team of AUVs by a tetrahedral configuration

This paper investigates the principles of a Cooperative Localization Algorithm for a team of at least three Autonomous Underwater Vehicles (AUVs) with respect to a surface support ship, without the use of Ultra-Short Baseline (USBL). It is assumed that each AUV is equipped with a low-cost Inertial Measurement Unit (IMU), a compass and a depth sensor, but only one of them has a high accuracy navigation sensor such as the Doppler Velocity Log (DVL). The surface boat locates itself by means of Global Positioning System (GPS). Range measurements provided by acoustic modems allow to avoid an unbounded error growth in the position estimate of each AUV. A geometric method, based on a tetrahedral configuration to obtain a deterministic fix for position, is proposed. This method allows to extend the advantages of the use of the DVL to the position estimate of other vehicles not equipped with DVL. The paper addresses also some of the problems related to the limitations of acoustic communication. The algorithm has been implemented and tested in simulations for a fleet of three AUVs and a surface support ship. An innovative cooperative localization algorithm for AUVs has been designed.Acoustic modems for communication are used as sensors of relative distance.The method is based on geometric relationships of a tetrahedral configuration.The algorithm performance are tested through a complete simulation model.A periodic reset of the estimation error is obtained for all the AUVs of the team.