Giovanni Boschetti

A haptic system for robotic assisted spine surgery

This paper deals with the problem of guiding an operator during the execution of a 5 degrees of freedom surgical teleoperation task. The work is focused on the feasibility of a spine surgery telerobotic system, made up of a haptic master, a slave robot, an optical tracking device and a main control unit. With this system, the surgeon performs a drilling operation by using a telerobotic device, being guided by haptic feedback: as soon as the vertebra moves, the tracking device measures vertebra pose and a proper force is exerted on the operators hand to let him/her adjust surgical tool position and orientation. Moreover, the haptic master produces the force feedback related to the teleoperation. The paper is focused on the design and implementation of this haptic system, with particular reference to control system architecture. Finally, some experimental results are presented

Orthostatic Hypotension Does Not Increase Cardiovascular Risk in the Elderly at a Population Level

BACKGROUND The general belief that orthostatic hypotension (OH) predisposes to cardiovascular events is based on sparse and contradictory data, rarely derived from population studies. METHODS A total of 1,016 men and women aged ≥65 years was studied in a 12-year epidemiological population-based study. Cardiovascular events were detected in subjects with and without OH (blood pressure (BP) decrease ≥20mm Hg for systolic or ≥10mm Hg for diastolic), and Cox analysis was performed including OH as an independent variable. RESULTS In univariate analysis, coronary (20.2% vs. 13.1%, P = 0.05), cerebrovascular (13.1% vs. 8.4%, P = 0.05), and heart failure (HF) events (20.2% vs. 13.8%, P = 0.03) were apparently more incidental in subjects with OH than in those without OH. Nevertheless, after adjusting for age, gender, and systolic BP as confounders, OH did not act as a cardiovascular predictor (relative risk for cerebrovascular events 1.33, 95% confidence interval (CI), 0.78-2.2, for coronary events 1.25, CI 0.82-1.88, for HF 1.07, CI 0.71-1.62, for arrhythmias 0.82, CI 0.40-1.37, and for syncope 0.58, CI 0.13-2.71). CONCLUSIONS Although OH seems to be a predictor of coronary, cerebrovascular, and HF events, no predictive role was found in models that include biological confounders. Independent of the cause of OH, age and systolic BP, which are positively associated with OH, fully explain the greater incidence of cardiovascular events and the greater cardiovascular risk observed in subjects with OH.

Cognitive Functions and Cognitive Reserve in Relation to Blood Pressure Components in a Population-Based Cohort Aged 53 to 94 Years

In 288 men and women from general population in a cross-sectional survey, all neuropsychological tests were negatively associated with age; memory and executive function were also positively related with education. The hypertensives (HT) were less efficient than the normotensives (NT) in the test of memory with interference at 10 sec (MI-10) (−33%, P = 0.03), clock drawing test (CLOX) (−28%, P < 0.01), and mini-mental state examination (MMSE) (−6%, P = 0.02). Lower MMSE, MI-10, and CLOX were predicted by higher systolic (odds ratio, OR, 0.97, P = 0.02; OR 0.98, P < 0.005; OR 0.95, P < 0.001) and higher pulse blood pressure (BP) (OR 0.97, P = 0.02; OR 0.97, P < 0.01; and 0.95, P < 0.0001). The cognitive reserve index (CRI) was 6% lower in the HT (P = 0.03) and was predicted by higher pulse BP (OR 0.82, P < 0.001). The BP vectors of lower MMSE, MI-10, and CLOX were directed towards higher values of systolic and diastolic BP, that of low CRI towards higher systolic and lower diastolic. The label of hypertension and higher values of systolic or pulse BP are associated to worse memory and executive functions. Higher diastolic BP, although insufficient to impair cognition, strengthens this association. CRI is predicted by higher systolic BP associated to lower diastolic BP.

Delayed Reference Control Applied to Flexible Link Mechanisms: A Scheme for Effective and Stable Control

This paper extends the use of delayed reference controllers to the simultaneous motion and vibration control of flexible link mechanisms. Vibration damping is achieved by introducing an “equivalent damping force” into the system through the computation of a suitable delayed time. The delayed time, which is based on the measured vibrations, is then employed in the trajectory planner to set the reference input. The stability of the controller is discussed and its effectiveness is proved by applying it to a four-bar planar linkage with flexible links.

Dietary Iron Intake and Cardiovascular Outcome in Italian Women: 10-Year Follow-Up

BACKGROUND Both low and high iron levels have been associated with cardiovascular outcome. The aim of this study was to determine if dietary iron intake is a cardiovascular predictor in women at a population level. METHODS A 138-item food frequency questionnaire (FFQ) was administered to 906 women aged 61.1±17.1 years from an unselected general population followed for 10 years. The mass of dietary items was calculated, and each food was resolved into its chemical components according to food composition tables conceived for Italian food. RESULTS An inverse association between iron intake and cardiovascular morbidity was found. Incident nonfatal cerebrovascular events were 10 of 302 (3.3%), 4 of 302 (1.3%), and 2 of 302 (0.7%) in the first, second, and third tertiles of nonheme iron intake (p for trend <0.01), respectively; fatal cerebrovascular events were 20 of 302 (6.6%), 13 of 302 (4.3%), and 5 of 302 (1.7%), respectively (p<0.01); nonfatal coronary events were 24 of 302 (7.9%), 13 of 302 (4.3%), and 10 of 302 (3.3%), respectively, and fatal coronary events were 20 of 302 (6.6%), 15 of 302 (5.0%), and 10 of 302 (3.3%), respectively (p<0.01). Independenly of confounders, hazard ratios (HR) and 95% confidence intervals (CI) of being the first rather than third tertile of nonheme iron intake were 5.00 (1.08-23.26), 3.18 (1.41-10.12), and 3.25 (1.39-7.59), respectively, for cerebrovascular and 2.48 (1.17-5.25), 2.25 (1.03-4.80), and 2.51 (1.39-4.53), respectively, for coronary events. Heme iron intake was not a predictor. CONCLUSIONS Based on a longitudinal population analysis, low iron intake seems to be an independent predictor of cerebrovascular and coronary morbidity and mortality in women.

Planar Robotic Systems for Upper-Limb Post-Stroke Rehabilitation

Rehabilitation is the only way to promote recovery of lost function in post-stroke hemiplegic subjects, leading to independence and early reintegration into social and domestic life. In particular, upper limb rehabilitation is fundamental to regain ability in Activities of Daily Living (ADLs). Robot-aided rehabilitation is an emerging field seeking to employ leading-edge robotic systems to increase patient recovery in the rehabilitation treatment. Even though the effectiveness of robotic therapy is still being discussed, the use of robotic devices can increase therapists’ efficiency by alleviating the labor-intensive aspects of physical rehabilitation, and can produce a reduction in treatment costs. This paper presents a comparison between different planar robotic devices designed for upper-limb rehabilitation in chronic patients. A planar configuration of the workspace leads to straightforward mechanical and control system design, and allows to define very simple and understandable treatment exercises. Also, the graphical user interface becomes very intuitive for the patient, and a set of Cartesian-based measures of the patient’s performance can be defined easily. In the paper, SCARA (Selective Compliance Assembly Robot Arm) robots such as the MIT-Manus, Cartesian robots and cable-driven robots are considered and compared in terms of inertial properties and force exertion capabilities. Two cable-driven devices, designed at the Robotics Lab of the Department if Innovation In Mechanics and Management, University of Padua, Italy, are presented for the first time. The first robot employs four driven cables to produce a planar force on the end-effector, whereas the second one is based on a three-cable configuration plus a linear actuator to obtain better overall robot performance.© 2008 ASME

The C825T GNB3 polymorphism, independent of blood pressure, predicts cerebrovascular risk at a population level

BACKGROUND The role of C825T polymorphism of the candidate GNB3 gene in predicting cerebrovascular outcome has been poorly explored in longitudinal setting at a population level. METHODS In an epidemiological setting, 1,678 men and women from general population were genotyped for C825T polymorphism of GNB3 gene and follow-up for 10 years to detect nonfatal and fatal cerebrovascular events (CE). Established cerebrovascular risk factors were used to adjust the multivariate Cox analysis for confounders. RESULTS Seventy-three nonfatal and 30 fatal CE were recorded. Incidence of CE was higher in TT than in C-carriers (fatal: 2.6 vs. 1.7%, P < 0.03; nonfatal: 7.8 vs. 3.9%, P < 0.03; fatal recurrences: 1.6 vs. 0.6%, P < 0.03). In Cox analysis, the TT genotype predicted nonfatal (hazard ratio 1.99, 95% confidence interval 1.05-3.79, P = 0.03), fatal (2.91, 1.05-8.12, P = 0.04), and fatal recurrent CE (6.82, 1.50-31.1, P = 0.02) also after adjustment for age, gender, systolic and diastolic blood pressure, body adiposity, atherogenetic blood lipids, serum uric acid, diabetes, calories, caffeine and ethanol intake, and coronary events at baseline. Further adjustment for historical CE made the association between TT genotype and incident fatal CE nonsignificant (hazard ratio 2.72, 95% confidence interval 0.96-7.22, P = 0.06). CONCLUSIONS The TT genotype of GNB3 gene predicts incident CE independent of blood pressure and other established risk factors at a population level. Further studies are needed to clarify the nature and pathways of this association.

Design of a single-dof active hand orthosis for neurorehabilitation

This paper is about the design of an active hand orthosis for hand rehabilitation in the acute and sub-acute phase after stroke. The device presented here was conceived as an add-on for the cable-suspended robots for upper limb rehabilitation developed at the Department of Innovation in Mechanics and Management of University of Padua, Italy. With this improvement, we aim to deliver coordinated distal and proximal robotic active-assistive mobilization in the early days after stroke. The hand orthosis employs one elastic actuator to produce force controlled trajectories of the fingers, keeping a highly compliant interaction with the patient during the assisted training of the paretic hand. This feature is particularly desirable in the rehabilitation treatment of acute and sub-acute patients. In the paper, both medical and engineering issues are addressed, and mechanical and control system design are presented with major details.

A Picking Strategy for Circular Conveyor Tracking

In modern assembly lines, one of the most relevant issues is the automatic part feeding. This task consists in the separation of parts delivered in bulk and their presentation in a certain amount and orientation at the pick-up location. The traditional vibratory bowl feeder can no longer be adopted for the modern plants which require high velocity and increasing flexibility. In this paper, several types of feeders have been indentified and the Ars FlexiBowl has been classified as one of the most innovative. In order to take full advantage from this rotating feeder, a proper path planning technique is proposed for a generic manipulator. Such an approach consists mainly of two algorithms: one for prediction of moving part position, and one for circular conveyor tracking. These algorithms can be implemented into the robot control unit by exploiting the internal trajectory planner. This strategy has been implemented into an Adept robotic workcell, which has been adopted as an experimental setup. Such an application proves the usefulness of the proposed algorithms.

A Non-Time Based Controller for Load Swing Damping and Path-Tracking in Robotic Cranes

This paper proposes the use of the non-time based control strategy named Delayed Reference Control (DRC) to the control of industrial robotic cranes. Such a control scheme has been developed to achieve two relevant objectives in the control of autonomous operated cranes: the active damping of undesired load swing, and the accurate tracking of the planned path through space, with the preservation of the coordinated Cartesian motion of the crane. A paramount advantage of the proposed scheme over traditional ones is its ease of implementation on industrial devices: it can be implemented by just adding an outer control loop (incorporating path planning) to standard position controllers. Experimental performance assessment of the proposed control strategy is provided by applying the DRC to the control of the oscillation of a cable-suspended load moved by a parallel robot mimicking a robotic crane. In order to implement the DRC scheme on such an industrial robot it has been just necessary to manage path planning and the DRC algorithm on a separate real-time hardware computing the delay in the execution of the desired trajectory suitable to reduce load swing. Load swing has been detected by processing the images from two off-the-shelf cameras with a dedicated vision system. No customization of the robot industrial controller has been necessary.